SYNTHETIC DIESEL FUEL COMPOSITIONS, AND SYSTEMS AND METHODS OF MAKING THE SAME

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. Provisional Application No. 63/715,203, filed on Nov. 1, 2024, and U.S. Provisional Application No. 63/687,501, filed on Aug. 27, 2024. The entire contents of each of the foregoing applications is incorporated by reference herein.

BACKGROUND

Development of transportation technologies that afford decreased CO₂ emissions, is a priority. One such means is development of sustainable aviation fuel (SAF) and diesel.

Conventional grade 1 diesel (1-D) is a product from crude oil in the distillation window between 200° C. and 300° C., which includes approximately 75% aliphatic hydrocarbons (C₁₀H₂₀—C₁₅H₂₈) and about 25% aromatic hydrocarbons. Grade 2 diesel (2-D) is a product from crude oil in the distillation window between 150° C. and 400° C. with predominantly C₁₀-C₂₂ hydrocarbons. The production of diesel fuel is analogous to that of gasoline: first distillation, second various conversion steps, and third clean-up. Like gasoline, diesel fuel is mixed with several additives to adjust performance characteristics. Unlike gasoline, however, there are two main performance issues that additives in diesel fuel address. The first is inhibiting fuel injector nozzle deposits and the second is maintaining fuel flowability in cold weather when temperature falls below a certain point.

Since diesel fuel has a broad variety of characteristics, several definitions and various classifications are used in different countries, for example, DIN EN 590 in Europe. Since 2009, ultra-low sulfur diesel may only contain 10 ppm sulfur in Europe, whereas, in the USA, road diesel may contain up to 15 ppm. Since 2010, diesel fuel may contain up to 7 vol. % fatty acid methyl ester (FAME) in Europe to meet biofuels directives. There is a need for technologies that produce synthetic diesel that can be directly substituted for diesel derived from crude oil.

SUMMARY OF THE DISCLOSURE

A CO₂-derived, synthetic diesel fuel composition is disclosed. The composition comprises: 0% to about 20 wt % monocyclic aromatics; less than about 2 wt % polycyclic aromatics; 0% to about 35 wt % cyclo-paraffins; about 5 wt % to about 40 wt % n-paraffins; about 20 wt % to about 80 wt % iso-paraffins; and 0 wt % to about 15 wt % oxygenates. The composition may comprise over about 80 wt % C₉-C₂₀ hydrocarbons; less than about 5 ppm total sulfur; and/or less than about 1 wt % polycyclic aromatics. The composition may comprise: from 0 wt % to about 2 wt % tetralins and indanes; less than about 0.5 wt % polycyclic aromatics; and/or about 5 wt % to about 35 wt % monocyclic aromatics. The composition may meet the requirements of diesel grade 1, diesel grade 2, or ASTM D975. The composition may have a cetane number of at least 40, or about 45 to about 60.

The diesel fuel composition may comprise about 1 wt % to about 25 wt % C_6-9 hydrocarbons, about 55 wt % to about 88 wt % C_10-18 hydrocarbons, and about 2 wt % to about 18 wt % C₁₉₊ hydrocarbons. The diesel fuel composition may comprise about 1 wt % to about 15 wt % C_6-9 hydrocarbons, about 65 wt % to about 88 wt % C_10-18 hydrocarbons, and about 2 wt % to about 20 wt % C₁₉₊ hydrocarbons.

A method for the production of a diesel fuel composition is also disclosed. That method may comprise:

• • i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford: a light hydrocarbon product mixture comprising one or more C_2-4 paraffins and/or olefins; a medium hydrocarbon product mixture comprising one or more C_5-8 paraffins and/or olefins; and a target hydrocarbon product mixture comprising one or more C_9-20 paraffins and/or olefins;
  • ii) contacting a first portion of the light hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with an aromatic catalyst to afford a light aromatic product mixture comprising one or more C_6-8 aromatics;
  • iii) contacting a second portion of the light hydrocarbon product mixture and the light aromatic product mixture with an alkylation catalyst to afford a target alkyl arene product mixture comprising one or more C₉₊ aromatics;
  • iv) contacting the medium hydrocarbon product mixture and/or a third portion of the light hydrocarbon product mixture with an oligomerization catalyst to afford a target oligomerized product mixture comprising one or more C₉₊ olefins and/or paraffins;
  • v) hydrogenating the target hydrocarbon product mixture, the target alkyl arene product mixture, and the target oligomerized product mixture to yield a target paraffin product mixture, a target cycloparaffin product mixture, and a target aromatic product mixture; and
  • vi) blending the target paraffin product mixture, the target cycloparaffin product mixture, and the target aromatic product mixture to afford the diesel fuel.

The step of hydrogenating may include: selective hydrogenating and fully hydrogenating. The method may comprise distilling the target paraffin product mixture, the target cycloparaffin product mixture, and the target aromatic product mixture before blending. The method may comprise a step of removing oxygenates from one or more of the product mixtures before or after steps ii), iii) or iv). The first reduction gas may be hydrogen, CO, and/or hydrocarbons, and the first carbon source gas may be CO₂.

Another Method of Making Diesel Fuel Comprises:

• • (i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford a hydrocarbon product mixture comprising olefins and paraffins;
  • (ii) hydrogenating the hydrocarbon product mixture to yield a target paraffin product mixture;
  • (iii) contacting a second reduction gas and a second carbon source gas with an aromatic catalyst to afford an aromatic product mixture comprising one or more aromatics and/or cyclic paraffins;
  • (iv) hydrogenating a first portion of the aromatic product mixture to yield a target cycloparaffin product mixture;
  • (v) hydrogenating a second portion of the aromatic product mixture to yield a target aromatic product mixture; and
  • (vi) blending the target paraffin product mixture, the target cycloparaffin product mixture and the target aromatic product mixture to afford diesel fuel.

The method may include contacting the target paraffin product mixture with an hydrogenation catalyst before blending. The method may include distilling one or more of the target paraffin product mixture, the target cycloparaffin product mixture and the target aromatic product mixture before blending.

Another Method for the Production of Paraffinic Diesel Fuel Disclosed Herein Comprises:

• • i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford a light hydrocarbon product mixture; a medium hydrocarbon product mixture, and a target hydrocarbon product mixture;
  • ii) removing oxygenates from the light hydrocarbon product mixture and the medium hydrocarbon product mixture to afford a converted light hydrocarbon product mixture and a converted medium hydrocarbon product mixture;
  • (i) contacting the converted light hydrocarbon product mixture and the converted medium hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with an oligomerization catalyst to afford an oligomerization product mixture;
  • (ii) hydrogenating the oligomerization product mixture and the target hydrocarbon product mixture to yield a target paraffin product mixture and a target cycloparaffin product mixture; and
  • (iii) blending the target paraffin product mixture and the target cycloparaffin product mixture to make paraffinic diesel fuel.

Another embodiment is directed to a system for the production of diesel fuel. The system may comprise: a first reduction gas feed; a first carbon source gas feed; a reduction reactor comprising a reduction catalyst; an aromatic reactor comprising an aromatic catalyst; an alkylation reactor comprising an alkylation catalyst, the alkylation reactor being coupled to the aromatic reactor; an oligomerization reactor comprising an oligomerization catalyst; and a blender. The system may further comprise an oxygenate removal system, at least one hydrogenation reactors, and/or a plurality of separators.

BRIEF DESCRIPTION OF THE FIGURE

FIG. 1 is an example of a process flow diagram for the production of fully formulated diesel fuel including steps of carbon conversion, oligomerization, aromatization and alkylation.

FIG. 2 is an example of a similar process flow to that of FIG. 1 but including additional hydrogenation and distillation steps for modification of the final product.

FIG. 3 is an example of a different process flow diagram for the production of fully formulated diesel fuel via direct CO₂ to paraffin and CO₂ to aromatics.

FIG. 4 is an example of a process flow diagram for the production of paraffinic diesel fuel.

FIG. 5 is an example of a process flow diagram incorporating an aromatic reactor comprising a reforming catalyst for the production of fully formulated diesel fuel.

DETAILED DESCRIPTION OF THE DISCLOSURE

A CO₂ derived, synthetic diesel fuel is disclosed herein, as well as methods and systems of making the same. The CO₂ derived, synthetic diesel fuel may comprise: monocyclic aromatics; polycyclic aromatics; cyclo-paraffins; n-paraffins; and iso-paraffins. The diesel fuel composition may be a CO₂ derived fully formulated product. The diesel fuel composition may be a CO₂ derived, synthetic, fully formulated product when it contains monocyclic aromatics. When the diesel fuel contains less than 5 wt % of aromatics and cycloparaffins, it may also be referred to as a paraffinic diesel fuel. The synthetic paraffinic

When not specified otherwise herein, when referring generally to a diesel fuel or diesel fuel composition that is intended to include both diesel fuel compositions containing aromatics in greater than 5 wt % and paraffinic diesel fuel compositions.

The diesel fuel composition herein may be formulated to meet the properties and requirements of diesel fuel grade #1, diesel fuel grade #2, or otherwise modified to meet the properties of any other diesel fuel, as desired and readily understood by one of skill in the art. The diesel fuel composition herein may be formulated to meet the properties and requirements of Winterized D (blend of #1 and #2), ULSD (ultra-low sulfur), or AG-D (red-dyed off road diesel). The diesel fuel composition herein may be formulated to meet the properties of F-76 military diesel.

For diesel fuels the key ASTM specifications are measured by the following tests: flash point, distillation temperature range, viscosity, cetane number, aromatic composition, and copper corrosion test. There are two major grades of diesel fuel, #1 and #2, with the latter being the most commonly used in general commerce, and in particular, the trucking industry. For many of the key specifications, the requirements for #1 diesel fuels are similar to, or somewhat less demanding than, the analogous ASTM specifications for jet fuels. The requirements for #2 diesel fuels reflect the higher average molecular weights and boiling ranges of these fuels.

The diesel fuel composition and properties thereof may be compliant with ASTM D975. The diesel fuel composition may be compliant with ASTM D2880. The diesel fuel composition may be compliant with ISO 4261. The diesel fuel composition may be compliant with ASTM D975, ASTM D2880 and ISO 4261.

The diesel fuel composition and properties thereof may be compliant with European standard, EN 590, as well as any specific country variations thereof. For the more temperate climatic zones, EN 590 defines six classes from A to F. For the colder (aka, polar or arctic) climatic zones, EN 590 defines five classes from 0 to 4. In Scandinavian countries, the winter diesel (Vinterdiesel) must meet Class 2 conditions. The different grades may be commonly differentiated as Winter Diesel (Winterdiesel, diesel d'hiver) and Arctic Diesel (Polardiesel, diesel polaires). The low cloud point (CP) and Cold Filter Plugging Point (CFPP) of EN 590 ensures that wax particles do not precipitate to the bottom of the tank upon standing because daytime temperatures might melt them together. The diesel fuel composition may be formulated to meet the requirements of any one of the classes defined in EN 590. The CFPP values set forth by category in EN 590 are shown in Table 1.

	TABLE 1
	EN 590 Class	CFPP Value	CloudPoint
	Class A (winter)	+5° C.
	Class B (winter)	0° C.
	Class C (winter)	−5° C.
	Class D (winter)	−10° C.
	Class E (winter)	−15° C.
	Class F (winter)	−20° C.
	Class 0 (arctic)	−20° C.	−10° C.
	Class 1 (arctic)	−26° C.	−16° C.
	Class 2 (arctic)	−32° C.	−22° C.
	Class 3 (arctic)	−38° C.	−28° C.
	Class 4 (arctic)	−44° C.	−34° C.

The present disclosure provides systems and methods for producing a diesel fuel composition from a carbon source gas (e.g., CO₂) and a reduction gas (e.g., H₂). The diesel fuel compositions produced by these systems and/or methods, e.g., the compositions described below, exhibit certain unique properties and compositional features. For example, these compositions have low total sulfur content because they (or their major components) are produced synthetically from CO₂. In addition, these compositions have a lower heteroatom content, e.g., phosphorus, nitrogen, arsenic, than conventional diesel fuels. As another example, the systems and processes disclosed herein for preparing the aromatic component heavily favor the creation of monocyclic aromatics, and disfavor the creation of polycyclic aromatics. Because of this low polycyclic aromatic content, these compositions will have less soot and solid residual than conventional diesel. These compositional features (e.g., low sulfur content, lower solids, and low polycyclic aromatic content), arising from the systems and processes described herein, are advantageous compared with conventional (petroleum-derived) fuels.

Furthermore, certain diesel fuel compositions made by the processes disclosed herein have a higher weight percentage of iso-paraffins than conventional diesel fuels due to incorporation of an oligomerization step introduced in the processing, and a lower weight percentage of polycyclic aromatics than conventional petroleum based diesel.

In Some Aspects, Provided Herein are Diesel Fuel Compositions Comprising:

• • 0 wt % to about 20 wt % monocyclic aromatics;
  • less than about 2 wt % polycyclic aromatics;
  • 0% to about 35 wt % cyclo-paraffins;
  • about 5 wt % to about 50 wt % n-paraffins;
  • about 15 wt % to about 80 wt % iso-paraffins; and
  • 0 wt % to about 15 wt % oxygenates.

In an Embodiment, the Diesel Fuel Composition Comprises:

• • 0 wt % to about 20 wt % monocyclic aromatics;
  • less than about 1 wt % polycyclic aromatics;
  • greater than 0% to about 35 wt % cyclo-paraffins;
  • about 5 wt % to about 40 wt % n-paraffins;
  • about 20 wt % to about 60 wt % iso-paraffins; and
  • 0 wt % to about 10 wt % oxygenates.

The diesel fuel composition may comprise C₉-C₂₅ hydrocarbons. The diesel fuel composition may comprise C₉-C₂₀ hydrocarbons. The composition may comprise over about 80 wt %, over about 85 wt %, over about 90 wt %, or over about 92 wt % C₉-C₂₀ hydrocarbons. The composition may comprise over about 80 wt % to about 100 wt %, about 85 wt % to about 99 wt %, about 90 wt % to about 99 wt %, or about 92 wt % to about 99 wt % C₉-C₂₀ hydrocarbons. The diesel fuel composition may comprise about 20 wt % to about 80 wt %, about 40 wt % to about 80 wt %, about 45 wt % to about 80 wt %, about 50 wt % to about 80 wt %, about 50 wt % to about 70 wt %, about 20 wt % to about 60 wt %, about 20 wt % to about 50 wt %, about 25 wt % to about 40 wt %, or about 25 wt % to about 35 wt %, C₁₄-C₂₀ hydrocarbons. The diesel fuel composition may comprise about 40 wt % to about 80 wt %, about 45 wt % to about 80 wt %, about 50 wt % to about 80 wt %, about 55 wt % to about 80 wt %, about 50 wt % to about 70 wt %, or about 55 wt % to about 70 wt % C₁₂-C₁₈ hydrocarbons.

The composition may comprise less than about 5 wt % tetralins and indanes. The composition may comprise less than about 2 wt % or less than about 1 wt % tetralins and indanes. The composition may comprise from 0 wt % to about 5 wt %, or from 0 wt % to about 2 wt % tetralins and indanes. The composition may comprise from 0 wt % to about 1 wt % tetralins and indanes. The composition may comprise essentially no tetralins and indanes.

The composition may comprise more than about 1 wt % to about 40 wt % aromatics, or more than about 5 wt % to about 40 wt % aromatics. The composition may comprise less about 2 wt %, less about 1 wt %, or less about 0.5 wt % polycyclic aromatics. In certain embodiments, the composition comprises from 0 wt % to about 1.5 wt %, about 0.1 wt % to about 1 wt %, or about 0.1 wt % to about 0.5 wt % polycyclic aromatics. In other embodiments, the composition comprises about 0.1 wt % or less, about 0.2 wt % or less, about 0.3 wt % or less, about 0.4 wt % or less, or about 0.5 wt % or less polycyclic aromatics. In still other embodiments, the composition comprises essentially no polycyclic aromatics, e.g., as determined by GC-MS.

In certain preferred embodiments, essentially all of the aromatic compounds present in fuel compositions of the present disclosure are monocyclic aromatics.

In certain embodiments, the composition comprises from about 1 wt % to about 40 wt %, about 5 wt % to about 40 wt %, about 5 wt % to about 35 wt %, about 10 wt % to about 30 wt %, 5 wt % to about 25 wt %, 8 wt % to about 20 wt %, about 20 wt % to about 40 wt %, about 15 wt % to about 35 wt %, about 5 wt % to about 20 wt %, or about 2 wt % to about 15 wt % monocyclic aromatics. In further embodiments, the composition comprises from about 8 wt % to about 15 wt % monocyclic aromatics. In yet further embodiments, the composition comprises about 8 wt %, about 9 wt %, about 10 wt %, about 11 wt %, about 12 wt %, about 13 wt %, or about 14 wt % monocyclic aromatics.

In certain embodiments, the composition comprises from about 0 wt % to about 30 wt %, about 10 wt % to about 30 wt %, about 0.1 wt % to about 25 wt %, about 1 wt % to about 20 wt %, about 1 wt % to about 15 wt %, about 1 wt % to about 10 wt %, or about 1 wt % to about 5 wt % % cyclo-paraffins, wherein the term “cyclo-paraffin” as used herein does not include aromatics. In further embodiments, the composition comprises from about 5 wt % to about 15 wt %, about 1 wt %, about 10 wt %, or about 10 wt % to about 25 wt % cyclo-paraffins.

In certain embodiments, the composition comprises about 15 wt % to about 80 wt %, about 15 wt % to about 60 wt %, about 20 wt % to about 60 wt %, about 25 wt % to about 60 wt %, about 30 wt % to about 60 wt %, about 25 wt % to about 50 wt %, about 15 wt % to about 40 wt %, about 15 wt % to about 35 wt %, about 55 wt % to about 70 wt %, or about 50 wt % to about 60 wt % iso-paraffins. In further embodiments, the composition comprises greater than about 15 wt % iso-paraffins, or greater than about 20 wt % iso-paraffins. In yet further embodiments, the composition comprises about 15 wt %, about 20 wt %, about 30 wt %, about 40 wt %, about 50 wt %, about 55 wt %, or about 60 wt % iso-paraffins.

In certain embodiments, the composition comprises from about 10 wt % to about 40 wt %, about 15 wt % to about 25 wt %, about 11 wt % to about 30 wt %, about 5 wt % to about 25 wt %, about 5 wt % to about 20 wt %, about 10 wt % to about 20 wt %, or about 5 wt % to about 15 wt % n-paraffins. In yet further embodiments, the composition comprises about 11 wt %, about 13 wt %, about 15 wt %, about 20 wt %, about 25 wt % n-paraffins.

In certain embodiments, the composition comprises from about 0 wt % to about 15 wt %, about 0.01 wt % to about 10 wt %, about 0.01 wt % to about 5 wt %, about 0.1 wt % to about 2 wt %, about 0.5 wt % to about 2 wt % or about 1 wt % to about 2 wt % oxygenates. When the composition comprises around 0.5 wt % oxygenates, this equates to about 5000 ppm. The oxygenates may comprise alcohols, such as C_5-18 alcohols, or C_5-12 alcohols. The oxygenates present in the diesel fuel composition may consist of alcohols. The composition may comprise from about 0 wt % to about 15 wt %, about 0.01 wt % to about 15 wt %, about 0.01 wt % to about 10 wt %, about 0.01 wt % to about 5 wt %, about 0.1 wt % to about 2 wt %, about 0.1 wt % to about 1 wt %, or about 0.1 wt % to about 0.5% alcohols. The oxygenates may comprise alcohols, ketones, and acids. The composition may comprise about 0.1 wt % to about 6 wt %, about 0.1 wt % to about 5 wt %, about 0.1 wt % to about 4 wt %. or about 3 wt % to about 4 wt % C_6-20 alcohols. The composition may comprise about 0 wt % to about 2 wt %, about 0.1 wt % to about 2 wt %, about 0.01 wt % to about 1 wt %, about 0.1 wt % to about 1 wt % or about 0.1 wt % to about 0.5 wt % C_7-20 ketones. The composition may comprise about 0 wt % to about 2 wt %, about 0 wt % to about 1 wt %, about 0.1 wt % to about 0.5 wt %, about 0 wt % to about 0.5 wt %, or less than about 0.5 wt % C_4-17 acids.

In an embodiment, the composition comprises about 15 wt % to about 40 wt % n-paraffins, about 15 wt % to about 60 wt % iso-paraffins, about 0 wt % to about 30 wt % aromatics, and about 0 wt % to about 30 wt % cycloparaffins. In an embodiment, the composition comprises about 15 wt % to about 40 wt % n-paraffins, about 15 wt % to about 60 wt % isoparaffins, about 10 wt % to about 30 wt % aromatics, and about 10 wt % to about 30 wt % cycloparaffins. In an embodiment, the composition comprises about 15 wt % to about 30 wt % n-paraffins, about 20 wt % to about 60 wt % isoparaffins, about 10 wt % to about 30 wt % aromatics, and about 10 wt % to about 30 wt % cycloparaffins. In another embodiment, the composition comprises about 5 wt % to about 20 wt % n-paraffins, about 30 wt % to about 35 wt % iso-paraffins, about 20 wt % to about 40 wt % aromatics, about 5 wt % to about 10 wt % cycloparaffins, about 2 wt % to about 4 wt % olefins, and about 6 wt % to about 20 wt % oxygenates.

In an embodiment, the composition comprises about 15 wt % to about 35 wt % aromatic and cycloparaffins, about 15 wt % to about 35 wt % of iso-paraffins, and about 25 wt % to about 40 wt % of n-paraffins.

In another embodiment, the composition comprises about 15 wt % to about 35 wt % of aromatic and cycloparaffins, about 30 wt % to about 60 wt % iso-paraffins, and about 25 wt % to about 40 wt % n-paraffins.

In certain embodiments, when there is less than about 5% monocyclic aromatics present in the diesel fuel composition, the diesel fuel composition may be referred to as a “paraffinic diesel composition” or “paraffinic diesel.” A paraffinic diesel composition may comprise over about 95 wt % of a mixture of iso-paraffins and n-paraffins. The paraffinic diesel composition may comprise over about 95 wt % of a mixture of iso-paraffins and n-paraffins, and less than about 5 wt % of a combination of aromatics, cycloparaffins, oxygenates.

The CO₂-derived paraffinic diesel composition may comprise: about 60 wt % to about 75 wt % of iso-paraffins and about 25 wt % to about 40 wt % of n-paraffins. The paraffinic diesel composition may comprise: about 60 wt % to about 75 wt % of iso-paraffins; about 25 wt % to about 40 wt % of n-paraffins; and less than about 5 wt % of a combination of aromatics, cycloparaffins, oxygenates. The paraffinic diesel composition may comprise: about 60 wt % to about 75 wt % of iso-paraffins; about 25 wt % to about 40 wt % of n-paraffins; and about 0 wt % to about 2 wt % of each of aromatics, cycloparaffins, and oxygenates. One of ordinary skill in the art will understand that the amount of iso-paraffin and n-paraffin may be adjusted as needed.

The paraffinic diesel composition may comprise C₉-C₂₅ isoparaffins and C₉-C₂₅ n-paraffins. The paraffinic diesel composition may comprise C₁₂-C₂₅ isoparaffins and C₁₂-C₂₅ n-paraffins. One of ordinary skill in the art will understand that the range of carbon numbers of the paraffins may be adjusted by modifying the separation, alkylation and/or oligomerization recycle to achieve the desired carbon number.

The process of making the diesel fuel composition includes several steps that can be adjusted to vary the carbon number range of the paraffins in the final product. A fractionation step applied after the initial CO₂ conversion can be used to narrow the carbon number range of the n-paraffins. In the alkylation process, the carbon number range of the olefin feed can significantly affect the carbon number range of the aromatic components, i.e., olefins with a higher carbon number will result in heavier fractions. In the oligomerization process, the carbon number range can be tuned by adjusting the feed composition of olefins, a feed having a higher content of olefins with a higher carbon number will result in a heavier product. However, olefins with a higher carbon number often exhibit lower reactivity, which requires a higher recycle ratio to improve conversion yield to a longer chain olefin in the oligomerization process. The diesel fuel composition disclosed herein may have a cetane number greater than about 40, greater than about 45, greater than about 50, or greater than about 55. The composition may have a cetane number from about 40 to about 65, about 40 to about 60, about 40 to about 55, or about 45 to about 55.

The composition may have a total acidity of less than about 5.0 mg KOH/g. In further embodiments, the composition has a total acidity of from about 0.05 mg KOH/g to about 5.0 mg KOH/g, about 0.1 mg KOH/g to about 5.0 mg KOH/g, about 0.15 mg KOH/g to about 4.5 mg KOH/g, about 0.25 mg KOH/g to about 4.0 mg KOH/g, about 1.0 mg KOH/g to about 4.0 mg KOH/g, about 2.0 mg KOH/g to about 5.0 mg KOH/g, about 0.05 mg KOH/g to about 2.0 mg KOH/g or about 3.0 mg KOH/g to about 4.5 mg KOH/g.

In certain embodiments, the composition comprises less than about 0.3 wt % total sulfur, for example as measured by ASTM D5453. In some embodiments, the composition comprises less than about 1 ppm sulfur-containing impurities. In certain embodiments, the composition comprises essentially no sulfur-containing impurities. In certain embodiments, the composition comprises less than about 0.003 wt % sulfur mercaptan. In certain preferred embodiments, the composition comprises about 0 wt % sulfur mercaptan, for example as measured by ASTM D3227. The composition may comprise less than about 5 ppm, less than about 2 ppm, or less than about 1 ppm total sulfur. The diesel fuel compositions may be referred to as ultra-low sulfur diesel fuel, which is defined as having a sulfur content below 15 ppm.

The composition may comprise less than about 100 ppb, less than about 90 ppb, less than about 80 ppb, less than about 70 ppb, or less than about 1 ppb mercaptan.

The composition may comprise less than about 5 ppm, less than about 2 ppm, or less than about 1 ppm of an additional heteroatom. The additional heteroatom may be a heteroatom other than sulfur. The additional heteroatom may be phosphorus, nitrogen or arsenic. The composition may comprise less than about 5 ppm, less than about 2 ppm, or less than about 1 ppm of any one heteroatom. The composition may comprise less than about 2 ppm, or less than about 1 ppm of each of phosphorus, nitrogen or arsenic. The composition may comprise essentially no phosphorus, nitrogen or arsenic. The composition may comprise essentially no phosphorus, nitrogen and arsenic.

The composition may have a flash point of at least about 38° C. The composition may have a flash point from about 38° C. to about 90° C., or from about 40° C. to about 88° C. In yet further embodiments, the composition has a flash point from about 40° C. to about 70° C., about 40° C. to about 60° C., about 50° C. to about 70° C., about 40° C. to about 50° C., or about 60° C. to about 85° C. In still further embodiments, the composition has a flash point of about 38° C., about 39° C., about 40° C., about 41° C., about 42° C., about 43° C., about 44° C., about 45° C., about 46° C., about 47° C., about 48° C., about 49° C., or about 50° C.

The composition may have a boiling point range from about 125° C. to about 400° C. The composition may have a boiling point from about 150° C. to about 385° C., about 150° C. to about 375° C., about 150° C. to about 350° C., about 170° C. to about 350° C., about 150° C. to about 300° C., about 180° C. to about 300° C., about 180° C. to about 250° C., about 250° C. to about 400° C. or about 150° C. to about 250° C.

The composition may have a density from about 760 kg/m³ to about 900 kg/m³ at 15° C. In certain embodiments, the composition has a density from about 775 kg/m³ to about 880 kg/m³ at 15° C. In certain embodiments, the paraffinic diesel fuel composition has a density from about 760 kg/m³ to about 800 kg/m³ at 15° C. In certain embodiments, the composition has a density of about 775 kg/m³, about 778 kg/m³, about 780 kg/m³, about 782 kg/m³, or about 785 kg/m³ at 15° C.

The composition may have a viscosity of less than about 6.0 mm²/s at 40° C., less than about 5.5 mm²/s at 40° C., less than about 5.0 mm²/s at 40° C., or less than about 4.0 mm²/s at 40° C. The composition may have a viscosity of about 1.0 to about 6.0 mm²/s at 40° C., about 1.0 to about 5.5 mm²/s at 40° C., about 1.0 to about 5.0 mm²/s at 40° C., or about 1.3 to about 4.5 mm²/s at 40° C.

In certain embodiments, the composition has a lubricity of HFRR at 60° C., below about 600 micron, or below about 550 micron. In certain embodiments, the composition has a lubricity of HFRR at 60° C., of about 300 micron to about 550 micron, or about 460 micron. The lubricity may be influenced by the oxygenate levels in the composition. The polar nature of oxygenates creates an affinity for solid surfaces that causes them to plate out to form a friction-reducing film.

In certain embodiments, the composition has a freezing point of less than about −20° C. In further embodiments, the composition has a freezing point of from about −70° C. to about −42° C. In yet further embodiments, the composition has a freezing point of about −70° C., about −65° C., about −60° C., about −55° C., about −50° C., about −45° C., or about −40° C. In certain preferred embodiments, the composition has a freezing point of about −51° C.

In certain embodiments, the composition has a net heat of combustion of at least about 30 MJ/kg. In further embodiments, the composition has a net heat of combustion of about 30 MJ/kg to about 51 MJ/kg, about 30 MJ/kg to about 45 MJ/kg, or about 30 MJ/kg to about 40 MJ/kg. In yet further embodiments, the composition has a net heat of combustion of about 30 MJ/kg, about 33 MJ/kg, about 40 MJ/kg, about 45 MJ/kg, about 49 MJ/kg, or about 51 MJ/kg. In certain preferred embodiments, the composition has a net heat of combustion of about 33 MJ/kg.

In certain embodiments, the composition has a smoke point of at least about 18 mm. In further embodiments, the composition has a smoke point of at least about 25 mm. In yet further embodiments, the composition has a smoke point of from about 25 mm to about 45 mm. In still further embodiments, the composition has a smoke point of about 25 mm, about 30 mm, about 35 mm, about 40 mm, or about 45 mm. In certain preferred embodiments, the composition has a smoke point of about 36 mm.

In some embodiments, the composition gives an ASTM D3241 filter pressure drop of less than about 25 mm Hg. In further embodiments, the composition gives an ASTM D3241 filter pressure drop of from 0 mm Hg to about 25 mm Hg. In certain preferred embodiments, the composition gives an ASTM D3241 filter pressure drop of about 0 mm Hg.

In certain embodiments, the composition gives an ASTM D3241 tube deposit rating of less than about 3, with essentially no peacock or abnormal color deposits. In certain preferred embodiments, the composition gives an ASTM D3241 tube deposit rating of 1 VTR Color Code.

In certain preferred embodiments, the monocyclic aromatics are not petroleum-derived. In some preferred embodiments, the monocyclic aromatics are derived from CO₂. In certain preferred embodiments, the monocyclic aromatics, cyclo-paraffins, n-paraffins, and iso-paraffins are not petroleum-derived. In some preferred embodiments, the monocyclic aromatics, cyclo-paraffins, n-paraffins, and iso-paraffins are derived from CO₂.

In certain embodiments, the composition further comprises at least one fuel additive.

The diesel fuel composition may comprise about 1 wt % to about 30 wt %, about 1 wt % to about 20 wt %, about 1 wt % to about 15 wt %, about 1 wt % to about 10 wt %, or about 1 wt % to about 6 wt % C_6-9 hydrocarbons. The diesel fuel composition may comprise about 35 wt % to about 85 wt %, about 40 wt % to about 85 wt %, about 50 wt % to about 85 wt %, about 20 wt % to about 70 wt %, or about 70 wt % to about 85 wt % C_10-16 hydrocarbons. The diesel fuel composition may comprise about 1 wt % to about 20 wt %, about 1 wt % to about 18 wt %, about 5 wt % to about 18 wt %, about 8 wt % to about 18 wt %, or about 9 wt % to about 15 wt % C₁₇₊ hydrocarbons. The diesel fuel composition may comprise less than about 4 wt %, or less than about 2 wt % C₅₋ hydrocarbons. The diesel fuel composition may comprise about 0.1 wt % to about 10 wt %, about 0.1 wt % to about 5 wt %, about 0.1 wt % to about 3 wt %, or about 1 wt % C₅₋ hydrocarbons.

The diesel fuel composition may comprise about 1 wt % to about 25 wt % C_6-9 hydrocarbons, about 55 wt % to about 88 wt % C_10-18 hydrocarbons, and about 2 wt % to about 20 wt % C₁₉₊ hydrocarbons. The diesel fuel composition may comprise about 1 wt % to about 15 wt % C_6-9 hydrocarbons, about 65 wt % to about 88 wt % C_10-18 hydrocarbons, and about 2 wt % to about 20 wt % C₁₉₊ hydrocarbons. The diesel fuel composition may comprise less than about 4 wt % C₅₋, about 1 wt % to about 10 wt % C_6-9 hydrocarbons, about 60 wt % to about 85 wt % C_10-18 hydrocarbons, and about 5 wt % to about 15 wt % C₁₉₊ hydrocarbons. The diesel fuel composition may comprise less than about 4 wt % C₅₋, about 1 wt % to about 6 wt % C_6-9 hydrocarbons, about 75 wt % to about 85 wt % C_10-18 hydrocarbons, and about 5 wt % to about 15 wt % C₁₉₊ hydrocarbons.

As used herein, certain components, fractions, and feeds are described in terms of the carbon numbers (e.g., C_X-Y) in said component, fraction, feed, etc. These descriptions indicate the possible (non-limiting) carbon numbers of the hydrocarbons present in said component, but do not require the presence of each and every carbon number within the range. For example, a feed described as comprising C_9-15 hydrocarbons must comprise at least one component falling within the range of carbon numbers listed. In another example, a feed described as comprising C₉₊ hydrocarbons must comprise at least one component falling within C₉ or above.

In certain embodiments, the disclosure includes mixtures comprising aromatics. These aromatics may be described in terms of a carbon number e.g., “C_X-Y aromatics.” As will be appreciated by one of skill in the art, this carbon number refers to the total number of carbon atoms in the molecule, and not necessarily to the number of ring atoms. For example, the group of compounds described by the term “C₁₀ aromatics” may include naphthalene (C₁₀H₈), butylbenzene (C₁₀H₁₄), etc.

Methods for Diesel Fuel Production

As described below, the present disclosure provides various methods for conversion of carbon source gases to diesel fuel. The disclosure includes exemplary process conditions (e.g., temperature, pressure, space velocities, etc.) which provide certain advantages in context of the systems and methods disclosed herein. However, any suitable conditions may be used, and the person of ordinary skill in the art will appreciate how to vary the conditions of any particular process described herein to obtain results and tune product distribution as needed for particular applications, as contemplated.

The present disclosure provides numerous catalysts that may be used to prepare paraffins, olefins, and mixtures thereof. The skilled artisan will recognize that any suitable catalyst or mixture of catalysts may be used in the methods and systems of the present disclosure to provide paraffins and olefins in the desirable ratios provided herein.

An embodiment is directed to a method of making synthetic diesel fuel comprising: i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford: a light hydrocarbon product mixture comprising one or more C_2-4 paraffins and/or olefins; a medium hydrocarbon product mixture comprising one or more C_5-8 paraffins and/or olefins; and a target hydrocarbon product mixture comprising one or more C_9-20 paraffins and/or olefins; ii) contacting a first portion of the medium hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas with an aromatic catalyst to afford a target aromatic product mixture comprising one or more C₉₊ aromatics; iii) contacting a second portion of the medium hydrocarbon product mixture, optionally a portion of the light hydrocarbon product mixture, optionally a third reduction gas, and optionally a third carbon source gas with an oligomerization catalyst to afford a target oligomerized product mixture comprising one or more C₉₊ olefins and/or paraffins; v) blending the target hydrocarbon product mixture, the target aromatic product mixture, and the target oligomerized product mixture to afford a crude product mixture; and vi) hydrogenating the crude product mixture to make diesel fuel.

Another Method of Making Synthetic Diesel Fuel May Comprise:

• • i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford: a light hydrocarbon product mixture comprising one or more C_2-4 paraffins and/or olefins; a medium hydrocarbon product mixture comprising one or more C_5-8 paraffins and/or olefins; and a target hydrocarbon product mixture comprising one or more C_9-20 paraffins and/or olefins;
  • ii) contacting a first portion of the light hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with an aromatic catalyst to afford a light aromatic product mixture comprising one or more C_6-8 aromatics;
  • iii) contacting a second portion of the light hydrocarbon product mixture and the light aromatic product mixture with an alkylation catalyst to afford a target alkyl arene product mixture comprising one or more C₉₊ aromatics;
  • iv) contacting the medium hydrocarbon product mixture, and optionally a third portion of the light hydrocarbon product mixture with an oligomerization catalyst to afford a target oligomerized product mixture comprising one or more C₉₊ olefins and/or paraffins;
  • v) hydrogenating the target hydrocarbon product mixture, the target alkyl arene product mixture, and the target oligomerized product mixture to yield a target paraffin product mixture, a target cycloparaffin product mixture, and a target aromatic product mixture; and
  • vi) blending the target paraffin product mixture, the target cycloparaffin product mixture, and the target aromatic product mixture to afford the diesel fuel.

The method may comprise separating the light hydrocarbon product mixture into a first portion and a second portion, and optionally a third portion. The method may further comprise mixing the light hydrocarbon product mixture and the medium hydrocarbon product mixture before the step of contacting with the aromatic catalyst, and/or before the step of contacting with the oligomerization catalyst, such that it a mixture of the light hydrocarbon product mixture and the medium hydrocarbon product mixture that undergoes these processing steps.

The method may further comprise the step of: removing oxygenates from the light hydrocarbon product mixture. The method may further comprise the step of: removing oxygenates from the second hydrocarbon product mixture. The method may further comprise the step of: removing oxygenates from the second light hydrocarbon product mixture and the second hydrocarbon product mixture before steps iii and iv.

The method may further comprise the step of: contacting the first portion of the light hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with the aromatic catalyst to afford the light aromatic product mixture and a target aromatic product mixture.

The step of hydrogenating may be performed in a number of steps with different streams being contacted with one or more hydrogenation catalysts at different operating conditions to obtain selective and full hydrogenation, as desired. The step of hydrogenating may comprise: selectively hydrogenating a first portion of the target alkyl arene product mixture to afford the target aromatic product mixture; and fully hydrogenating the target hydrocarbon product mixture, a second portion of the target alkyl arene product mixture, and the target oligomerized product mixture to afford the target paraffin product mixture, and the target cycloparaffin product mixture. The target paraffin product mixture comprises one or more C_10-16 paraffins, and the target cycloparaffin product mixture comprises C_10-18 cycloparaffins.

Removing oxygenates may be performed by any means known in the art. The oxygenates generated in the reduction reactor may include acids, alcohols, ketones, esters, ethers, phenols, and aldehydes. Removing oxygenates may comprise liquid-liquid base wash extraction, e.g., providing a base wash to remove acids. Removing oxygenates may comprise batch mixing with a molecular sieve. Batch mixing may be performed at room temperature or heated to about 60° C. Removing oxygenates may comprise room temperature batch adsorption on gamma alumina spheres. Removing oxygenates may comprise high temperature fixed bed conversion over gamma alumina spheres. In certain embodiments, removing oxygenates comprises a combination of two of more of the following processes: liquid-liquid base wash extraction; batch mixing with a molecular sieve; room temperature batch adsorption on gamma alumina spheres; and high temperature fixed bed conversion over gamma alumina spheres. High temperature fixed bed conversion over gamma alumina spheres may be performed at 200° C. to 400° C. and the oxygenates may be adsorbed or converted to olefins and paraffins. In the step of providing at least a portion of the light hydrocarbon product mixture and/or the medium hydrocarbon product mixture to an oxygenate removal system, or otherwise contacting at least a portion of the light hydrocarbon product mixture and/or the medium hydrocarbon product mixture with an oxygenate removal catalyst, the oxygenates present in the product mixtures are converted to olefins and paraffins to increase the yield of the process.

The step of removing oxygenates (or contacting a stream with an oxygenate removal catalyst) occurs at an oxygenate temperature from about 200° C. to about 500° C., or about 200° C. to about 450° C. and/or at an oxygenate pressure is from about 50 psi to about 1000 psi, from about 50 psi to about 700 psi, from about 50 psi to about 600 psi, or from about 50 psi to about 550 psi. Oxygenate removal may be carried out at a WHSV of about 1 to about 10 h−1, about 2 to about 6 h−1, or about 1 to about 4 h−1

The step of hydrogenating the crude product mixture, the target oligomerization product mixture, the target aromatic product mixture, and/or the target hydrocarbon product mixture may be performed by any means known in the art to achieve saturation of the hydrocarbons. The step of hydrogenating may comprise contacting the hydrogenating the crude product mixture, the target oligomerization product mixture, the target aromatic product mixture, and/or the target hydrocarbon product mixture with a hydrogenation catalyst in a hydrogenation reactor.

The hydrogenation reactor may be a fixed bed reactor where paraffin isomerization and aromatics hydrogenation occurs. Hydrogen is added to this hydrogenation reactor. The hydrogenation catalyst may be Pd or Pt on zeolite. In this reactor, a portion of the n-paraffins will be converted to iso-paraffins, and a portion of the aromatics will be converted to naphthenes to meet the product ratios required by the intended use, e.g. drop-in diesel fuel. The ratio of aromatics and paraffins entering the reactor is adjusted and fixed by the sizes of the other reactors in the system, and their respective feed rates, which may be adjusted as needed to afford desired product characteristics.

In certain embodiments, more than one hydrogenation reactor will be incorporated in the systems and methods of the disclosure. The hydrogenating step of the process may be before or after blending. When the hydrogenating step is before blending, it may include: selectively hydrogenating a first portion of the target alkyl arene product mixture to yield the target aromatic product mixture; and fully hydrogenating the target hydrocarbon product mixture, a second portion of the target alkyl arene product mixture, and the target oligomerized product mixture to yield the target paraffin product mixture, and the target cycloparaffin product mixture.

For selective (or partial) hydrogenation, only olefins and a portion of aromatics are hydrogenated, preserving a selected amount of aromatics. For full (or complete) hydrogenation, all unsaturation points are hydrogenated. To vary the degree of hydrogenation, the catalysts may be the same or different, and the temperature is higher for full hydrogenation than for partial hydrogenation. The pressure may be higher for full hydrogenation than for partial hydrogenation and/or the space velocity may be lower for full hydrogenation than for partial hydrogenation.

For partial hydrogenation, the hydrogenation reactor may be loaded with a nickel, palladium or platinum based catalyst. Partial hydrogenation may operate at a hydrogenation pressure of about 200 to about 800 psig, about 250 to about 450 psig, 300 to about 400 psig. Partial hydrogenation may operate at a hydrogenation temperature of about 50° C. to about 300° C., or about 100° C. to about 200° C. Partial hydrogenation may operate at a WHSV between about 2/hour to about 5/hour, or about 4/hour.

For full hydrogenation, the hydrogenation reactor may be loaded with a nickel, palladium or platinum based catalyst. Full hydrogenation may operate at a hydrogenation pressure of about 200 to about 800 psig, about 350 to about 600 psig, 400 to about 500 psig. Full hydrogenation may operate at a hydrogenation temperature of about 100° C. to about 300° C., or about 150° C. to about 250° C. Full hydrogenation may operate at a WHSV between about 2/hour to about 5/hour, or about 3/hour.

In certain embodiments, more than one hydrogenation reactor will be incorporated in the systems and methods of the disclosure. The hydrogenating step may occur before or after blending. When the hydrogenating step is before blending, it may include:

• • a. selectively hydrogenating the target alkyl arene product mixture to yield the target cycloparaffin product mixture and the target aromatic product mixture; and
  • b. fully hydrogenating the target hydrocarbon product mixture and the target oligomerized product mixture to yield the target paraffin product mixture.

In this embodiment, selective hydrogenating may be referred to as aromatic hydrogenation and full hydrogenation may be referred to as aliphatic hydrogenation. The processing parameters for aromatic hydrogenation may differ from the parameters for full hydrogenation wherein olefins and paraffins are also fed into the reactor. The selective hydrogenation where the aromatics are fed into the reactor may operate at lower pressure and temperature, where the complete hydrogenation will operate at higher pressure and temperatures.

A product column may be added to obtain the cut for the desired product (e.g., drop-in diesel fuel). Light and medium hydrocarbons generated may be recycled back into the system.

In certain embodiments, contacting the first reduction gas and the first carbon source gas with the reduction catalyst occurs at a paraffin temperature which may be at least 80° C., or at least 100° C., or at least 120° C. The paraffin temperature may be 550° C. or less, or 600° C. or less, or 650° C. or less. The paraffin temperature may be from about 100° C. to about 600° C., about 300° C. to about 600° C., about 200° C. to about 500° C., about 300° C. to about 450° C., about 300° C. to about 400° C., or about 350° C.

In certain embodiments, contacting the first reduction gas and the first carbon source gas with the reduction catalyst occurs at a paraffin pressure from about 50 psi to about 4000 psi. The paraffin pressure may be about 75 psi to about 1000 psi, about 75 psi to about 500 psi, or about 75 psi to about 225 psi. The paraffin pressure may be about 75 psi, about 100 psi, about 125 psi, about 150 psi, about 175 psi, about 200 psi, or about 225 psi.

In certain embodiments, contacting the first reduction gas and the first carbon source gas with the reduction catalyst occurs at a GHSV of about 1,000 to about 8,000 h⁻¹, about 2,000 to about 8,000 h⁻¹.

In certain embodiments, each of the light hydrocarbon product mixture, the medium product mixture, and/or the target hydrocarbon product mixture comprise olefins and paraffins. In further embodiments, the ratio of olefins to paraffins in each of the light hydrocarbon product mixture, the medium product mixture, and/or the target hydrocarbon product mixture is at least about 1:1, with the amount of olefins being about equal to or more than the amount of paraffins present therein. The ratio of olefins to paraffins in each of the light hydrocarbon product mixture, the medium product mixture, and/or the target hydrocarbon product mixture may be at least about 2:1, at least about 3:1, at least about 4:1, at least about 5:1, at least about 6:1, at least about 7:1, at least about 8:1, at least about 9:1, or at least about 10:1. The ratio of olefins to paraffins in each of the light hydrocarbon product mixture, the medium product mixture, and/or the target hydrocarbon product mixture may be about 1:1 to about 20:1, about 5:1 to about 20:1, or about 5:1 to about 15:1.

In certain embodiments, contacting the first reduction gas and the carbon source gas with a reduction catalyst further affords a light hydrocarbon product mixture comprising one or more C_2-4 paraffins and/or olefins. In some embodiments, the ratio of C_2-4 olefins to C_2-4 paraffins in the light hydrocarbon product mixture is at least about 5:1. In further embodiments, the ratio of C_2-4 olefins to C_2-4 paraffins in the light hydrocarbon product mixture is preferably at least about 8:1. In certain embodiments, the ratio of C_2-4 olefins to C_2-4 paraffins in the light hydrocarbon product mixture is about 5:1 to about 15:1, or about 8:1 to about 10:1. In certain embodiments, the ratio of C_2-4 olefins to C_2-4 paraffins in the light hydrocarbon product mixture is about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, or about 10:1.

In some embodiments, the medium hydrocarbon product mixture comprises one or more C_5-8 paraffins and olefins. In certain embodiments, the ratio of C_5-8 olefins to C_5-8 paraffins in the medium hydrocarbon product mixture is at least about 3:1, or at least about 5:1. In certain embodiments, the ratio of C_5-8 olefins to C_5-8 paraffins in the medium hydrocarbon product mixture is about 3:1 to about 12:1. In certain embodiments, the ratio of C_5-8 olefins to C_5-8 paraffins in the medium hydrocarbon product mixture is about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, or about 8:1.

In certain embodiments, methods of the disclosure involve mixtures comprising aromatics. These aromatics may be described in terms of a carbon number e.g., “C_X-Y aromatics.” As will be appreciated by one of skill in the art, this carbon number refers to the total number of carbon atoms in the molecule, and not necessarily to the number of ring atoms. For example, the group of compounds described by the term “C₁₀ aromatics” may include naphthalene (C₁₀H₈), butylbenzene (C₁₀H₁₄), etc.

In some embodiments, contacting the medium hydrocarbon product mixture, optionally the second reduction gas, and optionally the second carbon source gas, with an aromatic catalyst occurs at an aromatic temperature from about 100° C. to about 550° C., about 400° C. to about 550° C., about 400° C. to about 550° C., about 450° C. to about 550° C., about 300° C. to about 500° C., about 300° C. to about 450° C., or about 300° C. to about 400° C.

In some embodiments, contacting the second reduction gas and the second carbon source gas with the aromatic catalyst occurs at an aromatic pressure is from about 50 psi to about 3000 psi, from about 50 psi to about 1000 psi, from about 150 psi to about 1000 psi, or from about 300 psi to about 1000 psi.

In certain embodiments, contacting a second reduction gas and a second carbon source gas with an aromatic catalyst to afford an aromatic product mixture comprising one or more aromatics and/or cyclic paraffins is carried out at an aromatic standard Gas Hourly Space Velocity (aromatic GHSV) of from about 8000 mL/g*h to about 12000 mL/g*h. In further embodiments, the aromatic GHSV is from about 8750 mL/g*h to about 9250 mL/g*h. In still further embodiments, the aromatic GHSV is about 8750 mL/g*h, about 9000 mL/g*h, or about 9250 mL/g*h. In preferred embodiments, the paraffin GHSV is about 9000 mL/g*h.

Methods of the disclosure may further comprise passing the medium hydrocarbon product mixture through an adsorbent bed prior to contacting with the aromatic catalyst.

In certain embodiments, contacting the medium hydrocarbon product mixture with the aromatic catalyst further affords a light aromatic product mixture comprising one or more C_6-8 aromatics.

In certain embodiments, contacting the medium hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with an aromatic catalyst occurs at an aromatic pressure from about 50 psi to about 1000 psi.

Methods of the disclosure may further comprise contacting the light hydrocarbon product mixture and the target aromatic product mixture with an alkylation catalyst to afford a target alkyl arene product mixture comprising one or more alkylated aromatics. In certain such embodiments, contacting the light hydrocarbon product mixture and the target aromatic product mixture with an alkylation catalyst may be performed with any suitable catalyst under any suitable conditions. In certain embodiments, contacting the light hydrocarbon product mixture and the target aromatic product mixture with the alkylation catalyst occurs at an alkylation temperature. The alkylation temperature may be about 50° C. to about 350° C., about 100° C. to about 350° C., about 100° C. to about 300° C., about 100° C. to about 250° C., about 50° C. to about 250° C., or about 80° C. to about 230° C.

In certain embodiments, contacting the light hydrocarbon product mixture and the target aromatic product mixture with an alkylation catalyst occurs at an alkylation pressure. The alkylation pressure may be about 0 psig to about 1000 psig, about 100 psig to about 700 psig, about 200 psig to about 600 psig, about 200 psig to about 500 psig, about 0 psig to about 200 psig, about 10 psig to about 120 psig, or about 20 psig to about 100 psig.

Methods of the disclosure may comprise contacting all or a portion of the medium hydrocarbon product mixture with an oligomerization catalyst to afford a target oligomerized product mixture comprising one or more C_10-16 paraffins and/or olefins. Methods of the disclosure may comprise contacting all or a portion of the light hydrocarbon product mixture, and all or a portion of the medium hydrocarbon product mixture with an oligomerization catalyst to afford a target oligomerized product mixture comprising one or more C_10-16 paraffins and/or olefins. In certain embodiments, the light hydrocarbon product mixture, and the medium hydrocarbon product mixture are combined, and optionally divided into two or more streams, prior to contacting with the oligomerization catalyst.

Because olefins with carbon number C_2-8 will be fed into oligomerization reactor, a target oligomerized product, e.g. C₁₀₊ or C_10-20, having a higher molecular weight branched-aliphatic product will be generated

Methods of the disclosure may further comprise contacting the light hydrocarbon product mixture and the light aromatic product mixture with an alkylation catalyst and an oligomerization catalyst to afford a mixed target product mixture comprising one or more C_9-14 aromatics and one or more C_10-16 paraffins and/or olefins.

In some embodiments, it is desirable to oligomerize the olefins produced from CO₂ by methods of the disclosure in the presence of an oligomerization catalyst to produce a mixture of higher olefins. As used herein, the modifier “higher” with respect to hydrocarbons (e.g., paraffins) or olefins will refer to hydrocarbons (e.g., paraffins) or olefins with a higher number of carbons than a precursor. Exemplary higher hydrocarbons (e.g., paraffins) and olefins include, but are not limited to C₈-C₁₆ hydrocarbons (e.g., paraffins) and/or olefins. Said oligomerization process can be carried out in a fixed bed flow reactor, or any other suitable reactor type.

The temperature at which this oligomerization may be carried out can range from about 50° C. to about 1000° C. as needed to tailor the degree of oligomerization based on the desired product length and distribution. The oligomerization temperature may be about 50° C. to about 400° C., about 50° C. to about 300° C., about 100° C. to about 350° C., about 150° C. to about 300° C., about 100° C. to about 250° C., about 50° C. to about 250° C., or about 80° C. to about 230° C. The oligomerization temperature may be about 50° C., about 150° C., about 250° C., about 350° C., or about 400° C.

Oligomerization may be carried out at a WHSV of about 1 to about 10 h−1, or about 2 to about 6 h⁻¹.

The pressure at which this oligomerization may be carried out can range from about 0 psi to about 1000 psi as needed to tailor the degree of oligomerization based on the desired product length and distribution. The oligomerization pressure may be about 0 psi to about 500 psi, about 0 psi to about 400 psi, about 0 psi to about 300 psi, about 0 psi to about 200 psi, about 10 psi to about 120 psi, or about 20 psi to about 100 psi. The oligomerization pressure may be about 0 psi, about 10 psi, about 20 psi, about 40 psi, about 60 psi, about 80 psi, about 90 psi, about 100 psi, about 120 psi, or about 150 psi.

One of ordinary skill in the art will readily understand that some or all of the products and mixtures from any one or more of the reactors used in the method or systems disclosed herein may be subjected to certain treatments such as hydrogenation and/or absorption for removing impurities before blending.

Methods may further include blending the target hydrocarbon product mixture, the target aromatic product mixture, the target oligomerized product mixture, and/or the target alkyl arene product mixture to produce a crude product mixture. The method may comprise hydrogenating the crude product mixture to make diesel fuel.

The method may further comprise the step of: removing oxygenates from the target oligomerized product mixture before blending.

FIG. 1 is an example of a process for making CO₂-derived synthetic diesel fuel. In this example CO₂ and H₂ are fed into a reduction reactor and undergo CO₂ hydrogenation to yield a target hydrocarbon product stream comprising C₉₊ olefins and a mixed hydrocarbon product stream comprising C_2-8 olefins. The mixed hydrocarbon product stream is divided with a first portion being processed by aromatization followed by alkylation to yield a target aromatization and/or target alkyl arene product comprising C₉₊ aromatics, and a second portion being processed by oligomerization to yield target oligomerization product comprising C₉₊ olefins. The figure also shows the target hydrocarbon product being processed to remove oxygenates. It will be readily envisioned that the process to remove oxygenates may be incorporated into the scheme where shown in FIG. 1 or in other places within the scheme, e.g., i) after hydrogenation and before the product streams are divided, ii) before the medium hydrocarbon mixture contacts the aromatic catalyst and oligomerization catalyst, iii) after oligomerization, and before or after blending, or iv) a combination of the foregoing. The target oligomerization product, the target aromatization and/or target alkyl arene product, and the target hydrocarbon product are blended and then the blended product mixture undergoes hydrogenation to yield diesel fuel. The entirety of the target oligomerization product may be fed directly to the hydrogenation reactor to generate saturated hydrocarbons. Because diesel has no hard requirement on olefinic and oxygenates, hydrogenation and oxygenate removal will not need to run at as harsh conditions as with aviation fuel generation. Thus, the hydrogenation process may operate at milder conditions, and, as a result, the diesel fuel product out of the hydrogenation reactor may have certain amount of olefinic, aromatics and oxygenates (likely alcohols). Polar molecules (e.g., oxygenates, and olefins) will be in the range of about 1000 ppm to about 2000 ppm.

In the embodiment of FIG. 2, CO₂ and H₂ are fed into the reduction reactor for CO₂ hydrogenation, where the effluent is separated into 3 streams: i) a gaseous stream containing a light hydrocarbon product mixture of olefins and paraffins, ii) a medium hydrocarbon product mixture containing short chain oxygenates, and iii) an oil stream comprising the heavy hydrocarbon product mixture. A first separator is configured to provide: a light hydrocarbon product stream comprising C₃-C₅ hydrocarbon which is fed into the aromatization reactor to form aromatics from a mixture of light (C₃-C₅) olefins and paraffins; a medium hydrocarbon product stream comprising C₃-C₉ hydrocarbon which is fed into the oxygenate removal system; and a third target hydrocarbon product mixture comprising C_9-20 hydrocarbon which is fed to a full hydrogenation unit. After conversion in the oxygenate removal system, where oxygenates are converted to hydrocarbons, the product is split into two streams: a converted light hydrocarbon stream comprising C₃-C₅ hydrocarbons, which is fed to an alkylation reactor; and a converted medium hydrocarbon stream comprising C₃-C₉ hydrocarbons, which is fed to an oligomerization reactor to further increase the carbon number. The aromatic product stream from the aromatic reactor is also fed to the alkylation reactor to produce a target alkyl arene product. The target alkyl arene product is split with a first portion being sent for partial hydrogenation and a second portion being sent for full hydrogenation. The target oligomerization product mixture is also sent to for full hydrogenation producing a mixture of a target paraffin product and a target cycloparaffin product. The target paraffin product and target cycloparaffin product and target aromatic product are optionally distilled (not shown) and blended in a desired blend ratio to meet the requirements of the desired diesel fuel.

The diesel fuel compositions disclosed herein may be made by any method or system for making a paraffin product mixture, an aromatic product mixture, or otherwise disclosed in co-owned U.S. Patent Application Publication No. 2024/0124792, published on Apr. 18, 2024, titled: SYNTHETIC FUELS, AND METHODS AND APPARATUS FOR PRODUCTION THEREOF; and in co-owned U.S. Nonprovisional application Ser. No. 18/934,440, filed on Nov. 1, 2024, titled: SYSTEMS, METHODS, AND CATALYSTS FOR THE PRODUCTION OF SUSTAINABLE AVIATION FUEL; the entire contents of the foregoing applications are incorporated by reference herein.

In certain aspects, provided herein are methods for the conversion of carbon source gases and reduction gases to diesel fuel by direct CO₂ to aromatics and direct CO₂ to paraffins and olefins. That method comprises: (i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford a hydrocarbon product mixture comprising olefins and paraffins; (ii) hydrogenating the hydrocarbon product mixture to yield a target paraffin product mixture; (iii) contacting a second reduction gas and a second carbon source gas with an aromatic catalyst to afford an aromatic product mixture comprising one or more aromatics and/or cyclic paraffins; (iv) hydrogenating a first portion of the aromatic product mixture to yield a target cycloparaffin product mixture; (v) hydrogenating a second portion of the aromatic product mixture to yield a target aromatic product mixture; and (vi) blending the target paraffin product mixture, the target cycloparaffin product mixture and the target aromatic product mixture to afford diesel fuel.

Hydrogenation of the aromatics and C_2-9 isoparaffins may be adjusted to alter the ratio of aromatics:isoparaffin:n-paraffins in the final blending of the fuel. By altering the amount of light aromatics and light hydrocarbons vs the amount of medium hydrocarbons that are fed to the hydrogenation reactor, this changes the outcome. Adjusting the feed to the hydrogenation reactor also affects the ratio of aromatics:cycloparaffins in the final blending. Processing parameters (e.g., temperature, pressure and space velocity) may also be adjusted to affect the amount of hydrogenation and products. a. The hydrocarbon product mixture may comprise C_1-30 olefins and paraffins. The effluent from the reduction reactor may include about 15 wt % to about 30 wt % of the hydrocarbon product mixture. The effluent from the reduction reactor may also include unreacted CO₂ and hydrogen (for example, in an amount over about 50 wt %, or about 60 to about 80 wt %), CO (for example, in an amount of about 1 to about 10 wt %). The effluent from the reduction reactor may also include less than about 5 wt % or less than about 2 wt % aromatics and cyclic hydrocarbons, and less than about 5 wt % oxygenates.

The step of hydrogenating the hydrocarbon product mixture is configured to remove the olefinic hydrocarbons and oxygenates from the reduction reactor effluent. The effluent from the hydrogenation reactor may include about 90 to about 99 wt % aliphatic paraffinic hydrocarbons, less than about 1 wt % olefinic hydrocarbons, less than about 2 wt % aromatics and cycloparaffin, and/or less than about 5 wt % oxygenates.

The effluent from the aromatic reactor may include about 10 wt % to about 30 wt %, or about 10 wt % to about 20 wt % of aromatics and cyclic hydrocarbons. The effluent from the aromatic reactor may also include unreacted CO₂ and hydrogen (for example, in an amount over about 50 wt %, or about 60 to about 80 wt %), CO (for example, in an amount of about 1 to about 10 wt %). The effluent from the aromatic reactor may also include less than about 20 wt % of olefinic and paraffinic hydrocarbons.

The method may include contacting the target paraffin product mixture with an hydrogenation catalyst in a hydroisomerization reactor to generate iso-paraffins and increase iso-paraffin content in the target paraffin product mixture.

The method may comprise a step of distilling one or more of the target paraffin product mixture, the target cycloparaffin product mixture and the target aromatic product mixture before blending to remove undesirable light and C₁₇₊ hydrocarbons and achieve the desirable properties of the fuel.

The method may include a step of removing oxygenates from the aromatic product mixture or the hydrocarbon product mixture before hydrogenating.

The method may include contacting the hydrocarbon product mixture with an oligomerization catalyst to make a target oligomerization product, and hydrogenating target oligomerization product. The method may include contacting the aromatic product mixture with an alkylation catalyst before hydrogenating.

Provided herein are methods for the production of paraffinic diesel fuel. That method comprises: (i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford a light hydrocarbon product mixture; a medium hydrocarbon product mixture, and a target hydrocarbon product mixture; (ii) removing oxygenates from the light hydrocarbon product mixture and the medium hydrocarbon product mixture to afford a converted light hydrocarbon product mixture and a converted medium hydrocarbon product mixture; (iii) contacting the converted light hydrocarbon product mixture and the converted medium hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with an oligomerization catalyst to afford an oligomerization product mixture; (iv) hydrogenating the oligomerization product mixture and the target hydrocarbon product mixture to yield a target paraffin product mixture and a target cycloparaffin product mixture; and (v) blending the target paraffin product mixture and the target cycloparaffin product mixture to make paraffinic diesel fuel. The method may include one or more separation steps, optionally before or after blending to arrive at the desired product specifications, e.g., boiling point. In this method, the hydrogenation step may be fully hydrogenating to remove all points of unsaturation.

FIG. 4 is an example of a method and system of production of paraffinic diesel fuel. That figure includes a CO₂ and hydrogen feedstock being provided to a reduction reactor. The product is fed to a separator where the stream is split between a medium hydrocarbon stream comprising C_3-9 hydrocarbons and a target hydrocarbon product stream comprising C₉₊ hydrocarbons. The medium hydrocarbon stream is provided to an oxygenate removal system where the oxygenates in the stream are converted to olefinic and paraffinic hydrocarbons. The converted medium hydrocarbon stream is then processed in the oligomerization reactor to provide a target oligomerization product stream that is then mixed with the target hydrocarbon product stream and provided to a hydrogenation reactor to remove unsaturation in the hydrocarbons and produce target paraffin product and target cycloparaffin product. The target paraffin product and target cycloparaffin product are then blended to the desired specifications to make paraffinic diesel fuel. While not shown, it is readily envisioned that the target paraffin product and target cycloparaffin product may be distilled before or after blending to remove undesirable light and C₁₇₊ hydrocarbons.

Provided herein are methods for the production of diesel fuel incorporating a reforming unit. The methods may comprise: (i) contacting a first reduction gas and a first carbon source gas with a reduction catalyst to afford a light hydrocarbon product mixture; a medium hydrocarbon product mixture; and a target hydrocarbon product mixture; (ii) contacting the medium hydrocarbon product mixture, optionally a second reduction gas, and optionally a second carbon source gas, with an oligomerization catalyst to afford an oligomerization product mixture; (iii) contacting the light hydrocarbon product mixture and a light aromatic product mixture with an alkylation catalyst to afford a target alkyl arene product mixture; (vi) hydrogenating the target alkyl arene product mixture to yield a target aromatic product mixture; (v) hydrogenating the target hydrocarbon product mixture and the oligomerization product mixture to afford a target cycloparaffin product mixture and a hydrogenated paraffin product mixture comprising a light paraffin product mixture comprising one or more C_3-5 paraffins, a medium paraffin product mixture comprising one or more C_6-9 paraffins, and a target paraffin product mixture comprising one or more C_10-16 paraffins; and (vi) contacting the light paraffin product mixture and the medium paraffin product mixture with a reforming catalyst to afford a reformer product mixture comprising a light aromatic product mixture, and optionally a target aromatic product mixture; and (vii) blending the target aromatic product mixture, the target paraffin product mixture, and the target cycloparaffin product mixture to make diesel fuel.

The step of hydrogenating the target alkyl arene product mixture may yield a light paraffin product mixture and a medium paraffin product mixture, which may optionally also be co-fed into the aromatic reactor for contact with the reforming catalyst. The step of hydrogenating the target alkyl arene product mixture may be selective hydrogenation where only olefins are hydrogenated, preserving most aromatics. The step of hydrogenating the target hydrocarbon product mixture and the oligomerization product mixture may be full hydrogenation where all unsaturation points are hydrogenated.

The method may include: removing oxygenates from the light hydrocarbon product mixture before contacting with the alkylation catalyst. The method may include: removing oxygenates from the medium hydrocarbon product mixture before contacting with the oligomerization catalyst. The method may include: removing oxygenates from the light hydrocarbon product mixture and the medium hydrocarbon product mixture before steps ii and iii.

The method may further comprise separating the light hydrocarbon product mixture into a first portion the light hydrocarbon product and a second portion the light hydrocarbon product. Separating may occur before or after oxygenate removal, when present. The first portion of the light hydrocarbon product may come in contact with the alkylation catalyst and the second portion of the light hydrocarbon product may be mixed with the medium hydrocarbon mixture for contacting with the oligomerization catalyst.

The light hydrocarbon product mixture may comprise one or more C_3-5 paraffins and/or olefins. The hydrogenated paraffin product mixture may comprise a light paraffin product mixture comprising one or more C_1-5, a medium paraffin product mixture comprising one or more C_6-9 paraffins, and a target paraffin product mixture comprising one or more C_10-16 paraffins. The method may further comprise the step of alkylating the light aromatic product mixture with the converted medium hydrocarbon product mixture by contacting the light aromatic product mixture and the converted medium hydrocarbon product mixture with an alkylation catalyst to afford a target aromatic product mixture. The method may further comprise the step of hydrogenating at least a portion of the target aromatic product mixture to afford a target cycloparaffin product mixture.

Another step may include blending the target aromatic product mixture and the target paraffin product mixture to make diesel fuel. The method may include combining the target aromatic product mixture, the target cycloparaffin product mixture, and the target paraffin product mixture to make diesel fuel. The medium hydrocarbon product mixture may comprise one or more C_5-8 paraffins and/or olefins. The target hydrocarbon product mixture may comprise one or more C_9-20 paraffins and/or olefins, or one or more C_9-16 paraffins and/or olefins.

FIG. 5 is an example of a method and system of production of diesel fuel incorporating a reforming catalyst CO₂ and H₂ are fed into the reduction reactor for CO₂ hydrogenation, where the effluent is separated into 2 streams: i) a stream containing a light hydrocarbon product mixture of olefins and paraffins, and a medium hydrocarbon product mixture containing short chain oxygenates, and ii) a stream comprising the target hydrocarbon product mixture. The light and medium hydrocarbon product mixtures are contacted with a oxygenate removal catalyst where oxygenates are converted to hydrocarbons, the product is split into two streams: a first portion of converted light hydrocarbon stream comprising C₃-C₅ hydrocarbons, which is fed to an alkylation reactor; and a converted medium hydrocarbon stream comprising C₃-C₉ hydrocarbons, along with a second portion of converted light hydrocarbon stream, which is fed to an oligomerization reactor to further increase the carbon number, and afford a target oligomerization product mixture. The target hydrocarbon product mixture and the target oligomerization product mixture are also sent to for full hydrogenation (HYD-2) producing a mixture of a target paraffin product and a target cycloparaffin product. A portion of the target paraffin product is fed to the aromatic reactor along with a light paraffin product stream from partial hydrogenation. The aromatic product stream from the aromatic reactor is also fed to the alkylation reactor to produce a target alkyl arene product. The target alkyl arene product is split with a first portion being sent for partial hydrogenation and a second portion being sent for full hydrogenation. Partial hydrogenation affords the target aromatic product mixture desired for the diesel fuel composition. The target paraffin product and target cycloparaffin product and target aromatic product are optionally distilled (not shown) and blended in a desired blend ratio to meet the requirements of the desired diesel fuel.

Systems for Diesel Fuel Production

Provided herein are systems for the conversion of carbon source gases and reduction gases to diesel fuel. Certain components of these systems are described as being “coupled” to one another. As will be appreciated, the term “coupled” as used herein describes components that are operationally linked to one another, but does not preclude the presence of intervening components between those said to be coupled to one another. Additionally, as will be appreciated, various system components are described as “having” certain features. For example, in certain embodiments the paraffin reactor is described as having a first reduction gas feed inlet [23], a first carbon source inlet [23], and a paraffin product outlet [27]. Such descriptions do not preclude, and specifically contemplate, the presence of additional features, such as inlets, outlets, valves, control mechanisms, measurement devices, heating and/or cooling systems, etc. Additionally, in the systems of the present disclosure, certain components are described as having one or more outlets or inlets. Such outlets and inlets may represent separate structural elements, or may be combined into a single inlet or outlet as suitable. The person of ordinary skill in the art will recognize that, once the critical features and operating conditions of systems such as those described herein are understood, the detailed design and operation of such systems involved many choices, such as specific reagent flows, separation steps, etc. While the present disclosure provides a number of specific embodiments, any suitable combination of these design choices may be made.

A system for the production of diesel fuel may include: a first reduction gas feed; a first carbon source gas feed; a reduction reactor comprising a reduction catalyst; an aromatic reactor comprising an aromatic catalyst; an alkylation reactor comprising an alkylation catalyst, the alkylation reactor being coupled to the aromatic reactor; and an oligomerization reactor comprising an oligomerization catalyst. In certain embodiments, the system may further comprise: a second reduction gas feed, and a second carbon source gas feed. The system may further include a blender. The system may further include at least one hydrogenation reactor comprising a hydrogenation catalyst. The system may further include an oxygenate removal system coupled to the reduction reactor. A separator may be positioned between the oxygenate removal system and the reduction reactor.

The reduction reactor may have a first reduction gas feed inlet, a first carbon source feed inlet, and a mixed hydrocarbon outlet. In certain embodiments, the reduction reactor has a first reduction gas feed inlet, a first carbon source feed inlet, a target hydrocarbon outlet, and a medium hydrocarbon outlet. The first reduction gas feed inlet may be coupled to the first reduction gas feed. The first carbon source gas feed inlet may be coupled to the first carbon source gas feed. The reduction reactor may comprise a light hydrocarbon outlet, a medium hydrocarbon outlet, and a target hydrocarbon outlet.

The system may include the reduction reactor coupled to a first separator, which may further be coupled to one or more separators (e.g., distillation column or absorber). The first separator may be a three-phase separator. The three-phase separator may be any such separator known for use in the art for separating hydrocarbons based on weight, size or phase (i.e., gas, liquid and wastewater). The first separator may have a light hydrocarbon (e.g., C_2-4 hydrocarbons) outlet, a medium hydrocarbon (e.g., C_3-9 hydrocarbons) outlet, and a target (“C₉₊”) hydrocarbon outlet. It may also have other gas or wastewater outlets.

In an embodiment, the first separator is coupled to an absorber having an inlet coupled to the light hydrocarbon outlet, and the three-phase separator is also coupled to a distillation column having an inlet coupled to the target hydrocarbon outlet.

The aromatic reactor may include a light hydrocarbon inlet, optionally a second reduction gas feed inlet, optionally a second carbon source gas feed inlet, and a light aromatic product outlet. The aromatic reactor may further include a target aromatic product outlet. The light hydrocarbon inlet may be coupled to the light hydrocarbon outlet on the reduction reactor or separator, the second reduction gas feed inlet, when present, may be coupled to the second reduction gas feed, and the second carbon source gas feed inlet, when present, may be coupled to the second carbon source gas feed. The aromatic reactor may include a medium hydrocarbon inlet. The medium hydrocarbon inlet may be coupled to the medium hydrocarbon outlet on the reduction reactor or separator. The aromatic reactor may further comprise a light aromatic product outlet.

The systems of the disclosure may comprise a first adsorbent bed having a medium hydrocarbon inlet and a medium hydrocarbon outlet. The medium hydrocarbon inlet may be coupled to the medium hydrocarbon outlet on the reduction reactor or separator, and the medium hydrocarbon outlet may be coupled to the medium hydrocarbon inlet on the aromatic reactor.

The systems of the disclosure may comprise an alkylation reactor comprising an alkylation catalyst. The alkylation reactor may include a light hydrocarbon inlet, a light aromatic product inlet, and a target alkyl arene product outlet. The light hydrocarbon inlet may be coupled to the light hydrocarbon outlet on the reduction reactor or separator, and the light aromatic product inlet may be coupled to the light aromatic outlet on the aromatic reactor.

In certain embodiments, systems of the disclosure may comprise an oxygenate removal system coupled to the reduction reactor, or separator, when present. The oxygenate removal system may include a medium hydrocarbon inlet, a light hydrocarbon inlet, a converted light hydrocarbon outlet and a converted medium hydrocarbon outlet. The medium hydrocarbon inlet may be coupled to the medium hydrocarbon outlet on the reduction reactor or separator. The light hydrocarbon inlet may be coupled to the light hydrocarbon outlet on the reduction reactor or separator.

The oxygenate removal system may be coupled to the alkylation reactor and the oligomerization reactor.

The oxygenate removal system may comprise: a base wash to remove acids, batch mixing with a molecular sieve; room temperature batch adsorption on gamma alumina spheres; and/or high temperature fixed bed conversion over gamma alumina spheres and/or other metal oxide catalyst.

The oxygenate removal system may include an oxygenate removal reactor. Any reactor known in the art for use in the conversion of byproduct or impurity oxygenates to hydrocarbons may be used in the subject application. The oxygenate removal reactor may be loaded with an oxygenate removal catalyst. The oxygenate removal catalyst may be any known catalyst for use in oxygenate removal. The oxygenate removal catalyst may be a zeolite, such as Y-type zeolites, beta-zeolites, ZSM-type zeolites (e.g., ZSM-5, HZSM-5, ZSM-12, ZSM-22, ZSM-57), SAPO type zeolites (e.g., SAPO11, SAPO31, SAPO41), L zeolite (LTL), mordenite zeolites, MCM-49, MCM-22, DA-114, microcrystalline USY zeolite, microcrystalline USY zeolite, and combinations thereof. The oxygenate removal catalyst may be a SAPO-type zeolite, a ZSM-type zeolite, or MCM-49, MCM-22. The oxygenate removal catalyst may be SAPO11, SAPO31, SAPO41, PSH-3, MCM-49, or MCM-22. In certain embodiments, the oxygenate removal catalyst is SAPO11.

The systems of the disclosure may comprise an oligomerization reactor comprising an oligomerization catalyst. The oligomerization reactor may have a medium hydrocarbon inlet and a target oligomerized product outlet. The medium hydrocarbon inlet may be coupled to the medium hydrocarbon outlet on the reduction reactor, the separator, or the oxygenate removal system.

The systems of the disclosure may comprise an oligo-alkylation reactor comprising an oligomerization catalyst and an alkylation catalyst. The oligo-alkylation reactor may have a medium hydrocarbon inlet, a light aromatic product inlet, and a mixed target product outlet.

The oligomerization reactor and/or the oligo-alkylation reactor may comprise a target oligomerization product outlet. In some embodiments, the target oligomerization product outlet on the oligomerization reactor and/or the oligo-alkylation reactor is coupled to the first carbon source gas feed and/or the second carbon source gas feed.

In some embodiments, the oligomerization reactor, the alkylation reactor, and/or the oligo-alkylation reactor further comprise a medium oligomerized product inlet, wherein the medium oligomerized product inlet is coupled to the medium oligomerized product outlet on the oligomerization reactor and/or the oligo-alkylation reactor.

Systems of the disclosure may further comprise: a blender having a target hydrocarbon product inlet, a target aromatic product inlet, a target alkyl arene product inlet, a target oligomerization product inlet, and/or a mixed target product inlet, and a diesel fuel outlet. The target hydrocarbon inlet, when present, may be coupled to the target hydrocarbon product outlet on the reduction reactor; the target aromatic product inlet may be coupled to the target aromatic product outlet on the aromatic reactor; the alkyl arene product inlet, when present, may be coupled to the target alkyl arene product outlet on the alkylation reactor; the target oligomerization product inlet may be coupled to the target oligomerization product outlet on the oligomerization reactor; and the mixed target product inlet, when present, may be coupled to the mixed target product outlet on the oligo-alkylation reactor.

Systems of the disclosure may further comprise: at least one hydrogenation reactor comprising a hydrogenation catalyst. The at least one hydrogenation reactor may be coupled to the blender, either downstream or upstream from the blender. When the hydrogenation reactor receives a product from the blender, the hydrogenation reactor may comprise a crude product inlet and a diesel fuel outlet. When the blender receives products from the at least one hydrogenation reactor, the system may include a partial hydrogenation reactor comprising a first hydrogenation catalyst and a full hydrogenator comprising a second hydrogenation catalyst. The first and the second hydrogenation catalysts may be the same hydrogenation catalysts or different hydrogenation catalysts. The partial hydrogenation may operate at lower temperature and pressure, with elevated space velocity. The full hydrogenation reactor may operate at a higher hydrogenation temperature and higher hydrogenation pressure, with a reduced hydrogenation space velocity.

The partial hydrogenation reactor may comprise a target alkyl arene product inlet, and a target aromatic product outlet. The full hydrogenation reactor may comprise a target hydrocarbon product inlet, a target alkyl arene product inlet, a target oligomerization product inlet, and/or a mixed target product inlet, and a target paraffin product outlet and a target cycloparaffin product outlet. The target hydrocarbon inlet, when present, may be coupled to the target hydrocarbon product outlet on the reduction reactor or separator, when present; the target aromatic product inlet may be coupled to the target aromatic product outlet on the aromatic reactor; the target alkyl arene product inlet, when present, may be coupled to the target alkyl arene product outlet on the alkylation reactor; the target oligomerization product inlet may be coupled to the target oligomerization product outlet on the oligomerization reactor; and the mixed target product inlet, when present, may be coupled to the mixed target product outlet on the oligo-alkylation reactor.

When the blender is positioned downstream from the partial hydrogenation reactor and the full hydrogenation reactor, the blender includes a target aromatic product inlet, a target paraffin product inlet, a target cycloparaffin product inlet and a diesel fuel outlet. In certain embodiments, the system of the disclosure comprises: a reduction reactor, an aromatic reactor, an oligomerization reactor, an alkylation reactor, and a post-treatment system (e.g., for hydrotreating and fractionation). The system may include recycle streams and a plurality of separators. An example of such a system is depicted in FIG. 1 and in FIG. 2.

In an embodiment, systems for the production of fully formulated diesel via direct CO₂ to paraffin and CO₂ to aromatics are disclosed. That system comprises:

• • a first reduction gas feed;
  • a first carbon source feed;
  • a reduction reactor comprising a reduction catalyst, said reduction reactor having a first reduction gas feed inlet, a first carbon source inlet, and a mixed hydrocarbon outlet, wherein the first reduction gas feed is coupled to the first reduction gas feed inlet, and the first carbon source feed is coupled to the first carbon source feed inlet;
  • a second reduction gas feed;
  • a second carbon source feed;
  • an aromatic reactor comprising an aromatic catalyst, said aromatic reactor having a second reduction gas feed inlet, a second carbon source inlet, and an aromatic product outlet, wherein the second reduction gas feed is coupled to the second reduction gas feed inlet, and the second carbon source feed is coupled to the second carbon source feed inlet; and a blender having a mixed hydrocarbon inlet, an aromatic product inlet, and a blended product outlet, wherein the mixed hydrocarbon outlet from the reduction reactor is coupled to the mixed hydrocarbon inlet of the blender, and the aromatic product outlet from the aromatic reactor is coupled to the aromatic product inlet of the blender.

The system may comprise one or more hydrogenation reactors, which may be loaded with the same or different hydrogenation catalysts and may be operated at different conditions to achieve the desired result. The system may include one or more partial hydrogenation reactors and one or more full hydrogenation reactors.

The system may comprise an oligomerization reactor coupled to the reduction reactor and configured to yield a target oligomerization product. The system may comprise an alkylation reactor coupled to the aromatic reactor and configured to yield a target alkyl arene product.

The aromatic reactor may be coupled to a first hydrogenation reactor and a second hydrogenation reactor. The first hydrogenation reactor may be loaded with a nickel, palladium or platinum based catalyst. The first hydrogenation reactor may operate at a hydrogenation pressure of about 200 to about 800 psig and a hydrogenation temperature of about 180° C. to about 250° C. The first hydrogenation reactor may operate at a WHSV between about 2/hour to about 5/hour. The hydrogen to unsaturation ratio may be between about 1.1 and about 3 mole/mole The effluent from the first hydrogenation reactor may include about <20 wt % aliphatic paraffinic hydrocarbon, about 20 to about 70 wt % cycloparaffin, and about <20 wt % aromatics. The effluent from the first hydrogenation reactor may also include about <10 wt % oxygenate.

A separator, such as a distillation column, may be positioned between the first hydrogenation reactor and the blender to remove trace light fractions produced from hydrotreating, as well as heavy hydrocarbons (C₂₅⁺).

The second hydrogenation reactor may be configured to remove the olefinic product from the aromatic product mixture. The second hydrogenation reactor may be loaded with a nickel, palladium or platinum based catalyst. The second hydrogenation reactor may operate at a hydrogenation pressure of about 100 to about 400 psig and a hydrogenation temperature of about 80° C. to about 150° C. The second hydrogenation reactor may operate at a WHSV between about 3/hour to about 6/hour. The hydrogen to unsaturation ratio may be between about 1.1 and about 2 mole/mole The effluent from the second hydrogenation reactor may include about <20 wt % aliphatic paraffinic hydrocarbons, about <20 wt % cycloparaffins, and about 20 to about 70 wt % aromatics. The effluent from the second hydrogenation reactor may also include about <10 wt % oxygenate. A separator, such as a distillation column, may be positioned between the second hydrogenation reactor and the blender to remove trace light fractions produced from hydrotreating, as well as heavy hydrocarbons (C₂₅⁺).

The reduction reactor may be coupled to a third hydrogenation reactor configured to reduce the olefin and oxygenate content of the mixed hydrocarbon product. The third hydrogenation reactor may be loaded with a nickel, palladium or platinum based catalyst. The third hydrogenation reactor may operate at a hydrogenation pressure of about 300 to about 800 psig and a hydrogenation temperature of about 180° C. to about 250° C. The third hydrogenation reactor may operate at a WHSV between about 2/hour to about 5/hour. The hydrogen to unsaturation ratio may be between about 1.1 and about 5 mole/mole. The effluent of the process may include about 90-99 wt % paraffinic hydrocarbons.

The third hydrogenation reactor may be coupled to a hydroisomerization reactor loaded with a hydrogenation catalyst and configured to generate iso-paraffins. The hydroisomerization reactor may operate at about 120° C. to about 300° C. with a WHSV of about 1/hour to about 4/hour. The hydroisomerization reactor may operate at a pressure of about 100 to about 400 psig. The product may contain about 30 to about 70 wt % iso-paraffins with the remainder of the product being n-paraffins.

When the first, second and third hydrogenation reactors are present, the first hydrogenation reactor includes an aromatic product inlet and a target cycloparaffin product outlet, the second hydrogenation reactor includes an aromatic product inlet and a target aromatic product outlet, and the third hydrogenation reactor includes an mixed hydrocarbon inlet and a target paraffin product outlet. In certain embodiments, the blender includes a target cycloparaffin product inlet coupled to the target cycloparaffin product outlet on the first hydrogenator, a target aromatic product inlet coupled to the target aromatic product outlet on the second hydrogenator, and a target paraffin product inlet coupled to the target paraffin product outlet on the third hydrogenator.

The hydroisomerization reactor may be coupled to the blender. A separator, such as a distillation column, may be positioned between the hydroisomerization reactor and the blender.

FIG. 3 is an example of a method and system of production of fully formulated diesel fuel via direct CO₂ to paraffin and CO₂ to aromatics. That figure includes CO₂ and hydrogen feedstock being provided to a reduction reactor and to an aromatic reactor. The aromatic product stream is split with a first portion being fed into a first hydrogenation reactor and a second portion being fed into a second hydrogenation reactor. Multiple hydrogenation reactors are used to adjust the parameters to achieve varying amounts of hydrogenation and produce a target cycloparaffin product and a target aromatic product. The product from the reduction reactor is provided to a third hydrogenation reactor, then to a hydroisomerization reactor and then to a blender, in which the target paraffin product is mixed with target aromatic product and target cycloparaffin product from the first and second hydrogenation reactors to make a diesel fuel blended to the desired specifications. While not shown, it is readily envisioned that each of the target paraffin product, target aromatic product and target cycloparaffin product may be distilled before blending to remove undesirable light and heavy hydrocarbons.

A system is disclosed herein for making paraffinic diesel fuel including: a first reduction gas feed; a first carbon source gas feed; a reduction reactor comprising a reduction catalyst; optionally an oxygenate removal system; an oligomerization reactor comprising an oligomerization catalyst; at least one hydrogenation reactor comprising a hydrogenation catalyst; and a blender. The system may include one hydrogenation reactor. The system may include one or more separators. A first separator may be coupled to the reduction reactor configured to receive the mixed hydrocarbon product and separate that product into a medium hydrocarbon product comprising C_5-8 hydrocarbons and a target hydrocarbon product comprising C₉₊ hydrocarbons, optionally also a light hydrocarbon product comprising C_2-4 hydrocarbons. The first separator may include a target hydrocarbon outlet, a light hydrocarbon outlet, and a medium hydrocarbon outlet. The target hydrocarbon outlet may be coupled to a target hydrocarbon inlet on the hydrogenation reactor and the medium hydrocarbon outlet may be coupled to a medium hydrocarbon inlet on the oxygenate removal system. The light hydrocarbon outlet may be coupled to a light hydrocarbon inlet on the oxygenate removal system. The oxygenate removal system may include a medium hydrocarbon inlet, a light hydrocarbon inlet and a converted medium hydrocarbon outlet coupled to the converted medium hydrocarbon inlet on the oligomerization reactor. The oligomerization reactor may include a converted medium hydrocarbon inlet and a target oligomerization product outlet. The target oligomerization product outlet may be coupled to a target oligomerization product inlet on the hydrogenation reactor. The hydrogenation reactor may include a target oligomerization product inlet, a target hydrocarbon inlet and a target cycloparaffin outlet and a target paraffin outlet. The target cycloparaffin outlet and the target paraffin outlet may be coupled to a target cycloparaffin inlet and a target paraffin inlet on the blender.

To make fully formulated fuel, the system above may further include an alkylation reactor comprising an alkylation catalyst and an aromatic reactor comprising an aromatic catalyst. The alkylation reactor may include a light hydrocarbon inlet and a target alkyl arene product outlet. The light hydrocarbon inlet mat be coupled to the light hydrocarbon outlet on the first separator. The aromatic reactor may include a light hydrocarbon inlet and a light aromatic outlet. The light hydrocarbon inlet may be coupled to the light hydrocarbon outlet on the first separator; The alkylation reactor may comprise a light aromatic inlet coupled to the light aromatic product outlet on the aromatic reactor.

The system may further include a second hydrogenator having a target alkyl arene product inlet and a target aromatic product outlet. The target alkyl arene product inlet may be coupled to the target alkyl arene product outlet on the alkylation reactor. In this embodiment, the blender comprises a target aromatic product inlet and a target paraffin product outlet.

A system disclosed herein produces aromatics in the diesel fuel by incorporating an aromatic reactor loaded with a reforming catalyst. This aromatic reactor may also be referred to as a reforming unit. This system may include: a first reduction gas feed; a first carbon source gas feed; a reduction reactor comprising a reduction catalyst; an oxygenate removal system; an oligomerization reactor; an alkylation reactor; at least one hydrogenation reactor comprising a hydrogenation catalyst; and an aromatic reactor comprising a reforming catalyst. Between the reduction reactor and oxygenate removal system, and between the alkylation reactor and the hydrogenator may be one or more separators for separating gases, liquids and/or streams of light, medium, target and/or heavy hydrocarbons. The system may include the reduction reactor coupled to a first separator, which may further be coupled to one or more separators (e.g., distillation column or absorber). The first separator may divide the effluent into a target hydrocarbon product and a medium hydrocarbon product. The first separator may comprise a mixed product inlet, a medium hydrocarbon outlet and a target hydrocarbon outlet.

The system may include a blender coupled to the at least one hydrogenation reactor. The system may include a partial hydrogenation reactor comprising a first hydrogenation catalyst and a full hydrogenator comprising a second hydrogenation catalyst. The first and the second hydrogenation catalyst may be the same hydrogenation catalysts or different hydrogenation catalysts.

In this system, the feed to the aromatic reactor is not provided directly from CO₂ hydrogenation and separation, but instead, the mixed hydrocarbon product from CO₂ hydrogenation is processed through the oligomerization reactor and/or the alkylation reactor and hydrogenated (partially and/or fully) before being fed to the aromatic reactor. The alkylation reactor in these systems may include a light hydrocarbon inlet, a light aromatic product inlet, and a target alkyl arene product outlet. The light hydrocarbon inlet may be coupled to the light hydrocarbon outlet on the reduction reactor or separator, and the light aromatic product inlet may be coupled to the aromatic product outlet on the aromatic reactor.

In certain embodiments, systems of the disclosure may comprise an oxygenate removal system coupled to the reduction reactor, or separator, when present. The oxygenate removal system may include a medium hydrocarbon inlet, a converted light hydrocarbon outlet and a converted medium hydrocarbon outlet. The medium hydrocarbon inlet may be coupled to the medium hydrocarbon outlet on the reduction reactor or separator.

The oxygenate removal system may be coupled to the alkylation reactor and the oligomerization reactor.

Catalysts for Conversion of Carbon Sources to Olefins and Paraffins

The systems and methods of the present disclosure may include the use of a reduction catalyst. The conversion of carbon dioxide and carbon dioxide containing mixtures can be achieved through catalytic carbon dioxide transformations, where the reduction catalyst plays the key role in the process. Reduction catalysts, as used herein may also be understood to be carbon dioxide hydrogenation catalysts, which are catalysts that enhance carbon dioxide activation and conversion, and may also control the selectivity of the hydrogenation products. The reduction catalysts are active in the conversion of a carbon source gas, such as CO₂, to hydrocarbons comprising olefins and/or paraffins.

Any known reduction catalyst may be used in accordance with this disclosure.

Transition metal catalysts, especially base metals, are particularly effective as reduction catalysts due to their high electron density, various oxidation states and rich spectrum of metal-ceramic materials, which provides enhanced carbon dioxide activations and flexible tuning of transformation pathways. In addition to the metal elements, the reduction catalyst may contain one or more additional materials, such as a binder, lubricant and/or supporting material, which can be added to optimize the forming catalyst process, metal dispersity and other chemical and physical properties.

Certain commonly known reduction catalysts contain copper, iron, cobalt, or some combination thereof. The reduction catalyst may comprise copper. Copper catalysts are known to be one of the most efficient reduction catalysts producing oxygenates as the major products. These catalysts may include copper as the core metal with various supporting elements including but not limited to zinc, zirconium, aluminum, chromium, alkali metal and alkali earth metals. The supporting element, metal alloy and metal oxide provide electronic and structure support to better tune the reactivity and selectivity of carbon dioxide hydrogenation.

The reduction catalyst may comprise iron and/or cobalt. Iron and cobalt catalysts are widely used in carbon dioxide hydrogenation, and specifically used in the Fischer-Tropsch process, for example, to form longer chain hydrocarbon and oxygenate products. Similar to the copper family, iron and cobalt catalyst may contain additional metal promoters to improve both carbon dioxide adsorption and selectivity of the hydrogenation. The metal promoter may be selected from zinc, manganese, molybdenum, copper, nickel, alkali and alkali earth metals.

Reduction catalysts of the disclosure may comprise and/or be derived from a particular metal oxide, or a combination of multiple metal oxides. One of ordinary skill in the art will appreciate that during the various catalyst preparation and activation methods known in the art, and in those exemplified herein, some or all of the oxygen atoms of the metal oxide may become bonded to other atoms in the catalyst mixture, and/or may be removed from the catalyst mixture partially or entirely during an activation step (e.g., converted to CO₂ and removed). Additionally, one of ordinary skill in the art would appreciate that for such catalysts, e.g., the reduction and/or paraffin catalysts described below, the molar ratio of oxygen relative to the total composition may vary. Further, as will be understood, when defining catalysts made from metal oxides, the molar ratios of one metal to another are defined on a metal (rather than metal oxide) basis.

The reduction catalyst may be a paraffin catalyst or an olefin catalyst. As used herein, the term “paraffin catalyst” refers to a catalyst used for the conversion of carbon sources and reduction gases to paraffins, predominantly, but which catalyst does not necessarily itself comprise paraffins. A paraffin catalyst may be selected when the desired product is paraffins. The paraffin catalyst may be used for the conversion of carbon sources and reduction gases to paraffins predominantly, as well as olefins and/or other hydrocarbons in a minority amount. As used herein, the term “olefin catalyst” refers to a catalyst used for the conversion of carbon sources and reduction gases to olefins, predominantly, but which catalyst does not necessarily itself comprise olefins. An olefin catalyst may be selected when the desired product is olefins. The olefin catalyst may be used for the conversion of carbon sources and reduction gases to olefin predominantly, as well as paraffins and/or other hydrocarbons in a minority amount.

The reduction catalyst may comprise: zinc; one or more first elements selected from iron or cobalt; and oxygen or carbon or nitrogen. The reduction catalyst may comprise: copper; zinc; one or more first elements selected from iron or cobalt; and oxygen or carbon or nitrogen. The reduction catalyst may also include aluminum. The reduction catalyst may also include one or more second elements selected from a Group V, VI, VII, VIII, IX, X, and XI metal (e.g., manganese, chromium, silver, niobium, zirconium, molybdenum, ruthenium, palladium, platinum, or nickel). The reduction catalyst may also include one or more Group IA and IIA metals.

The reduction catalyst may comprise: zinc; one or more first elements selected from iron or cobalt; oxygen or carbon or nitrogen; and aluminum. The reduction catalyst of the disclosure may comprise: zinc; one or more first elements selected from iron or cobalt; oxygen or carbon or nitrogen; aluminum; and one or more second elements selected from a Group V, VI, VII, VIII, IX, X, and XI metal (e.g., manganese, silver, niobium, zirconium, molybdenum, ruthenium, palladium, platinum, or nickel). The reduction catalyst may comprise: zinc; one or more first elements selected from iron or cobalt; oxygen or carbon or nitrogen; aluminum; and one or more Group IA and IIA metals.

The reduction catalyst may comprise: copper; zinc; one or more first elements selected from iron or cobalt; oxygen or carbon or nitrogen; and aluminum. The reduction catalyst may comprise: copper; zinc; one or more first elements selected from iron or cobalt; oxygen or carbon or nitrogen; aluminum; and one or more second elements selected from a Group V, VI, VII, VIII, IX, X, and XI metal (e.g., manganese, silver, niobium, zirconium, molybdenum, ruthenium, palladium, platinum, or nickel). The reduction catalyst may comprise: copper; zinc; one or more first elements selected from iron or cobalt; oxygen or carbon or nitrogen; aluminum; and one or more Group IA and IIA metals.

The one or more first elements may be present in an amount of about 0.5 to about 40 wt. %, about 1 to about 40 wt. %, about 0.5 to about 20 wt. %, about 5 to about 30 wt. %, about 1 to about 10 wt. %, about 10 to about 20 wt. %, about 20 to about 30 wt. %, about 25 to about 40 wt. %, about 25 to about 30 wt. %, about 22 to about 24 wt. %, about 30 to about 40 wt. %, or about 35 to about 40 wt. %, of the total amount of the copper, zinc, cobalt, iron, the optional second element, and the optional Group IA and IIA metal.

The reduction catalyst may comprise a cobalt-embedded interconnected matrix of reduced copper metal nanoparticles and alumina-modified zinc oxide. In some embodiments, the cobalt is present as cobalt oxide. In some embodiments, the copper is present as copper oxide. In some embodiments, the molar ratio of cobalt to copper to zinc (Co:Cu:Zn) is about 0.1-100 in cobalt, 0.05-4 in copper, and 0.05-2 in zinc. In some embodiments, the Co:Cu:Zn ratio is in the range of 1-2 in cobalt, 1-3 in copper, and 0.5-1 in zinc. In some embodiments, the Co:Cu:Zn ratio is approximately 1:2.5:1. In some embodiments, the zinc is preferably 0.3-1 the molar content of the copper. In some embodiments, the cobalt is preferably 0.1-1 the molar content of the copper.

The reduction catalyst may comprise an iron-embedded interconnected matrix of reduced copper metal nanoparticles and alumina-modified zinc oxide. In some embodiments, the iron is present as iron oxide. In certain embodiments, the iron oxide is magnetite (Fe₃O₄), hematite (Fe₂O₃), or a combination thereof. In further embodiments, the iron oxide is magnetite (Fe₃O₄). In yet further embodiments, the iron oxide is a combination of magnetite (Fe₃O₄) and hematite (Fe₂O₃).

In some embodiments, the copper is present as copper oxide. In some embodiments, the molar ratio of iron to copper to zinc (Fe:Cu:Zn) is about 0.1 to about 100 in iron, about 0.05 to about 4 in copper, and about 0.05 to about 4 in zinc. In some embodiments, the Fe:Cu:Zn ratio is in the range of about 0.4 to about 2 in iron, about 1 to about 3 in copper, and about 0.5-3 in zinc. In some embodiments, the Fe:Cu:Zn ratio is approximately 1:2.3:2.3. In some embodiments, the zinc is preferably about 0.3 to about 1 the molar content of the copper. In some embodiments, the iron is about 0.5 to about 5 the molar content of the copper.

The reduction catalyst may comprise one or more elements selected from a transition, or Group VI, VII, VIII, IX, X, or XI metal. In some embodiments, the reduction catalyst comprises one or more second elements selected from a Group VI metal. In some embodiments, the reduction catalyst comprises one or more second elements selected from a Group VII metal. In some embodiments, the reduction catalyst comprises one or more second elements selected from a Group VIII metal. In some embodiments, the reduction catalyst comprises one or more second elements selected from a Group IX metal. In some embodiments, the reduction catalyst comprises one or more second elements selected from a Group X metal. In some embodiments, the reduction catalyst comprises one or more second elements selected from a Group XI metal.

The one or more second elements may comprise manganese, silver, niobium, zirconium, molybdenum, ruthenium, palladium, platinum, or nickel. The one or more second elements may comprise nickel. The one or more second elements comprise silver. The one or more second elements may comprise palladium. The one or more second elements may comprise niobium. The one or more second elements may comprise manganese. The one or more second elements may comprise zirconium. The one or more second elements may comprise molybdenum.

In some embodiments, the reduction catalyst comprises the one or more second elements at a molar ratio of about 0.05 to about 4, about 0.05 to about 3, about 0.05 to about 1, about 0.05 to about 0.75, about 0.05 to about 0.5, or about 0.05 to about 0.25 relative to the one or more first elements.

In some embodiments, the reduction catalyst comprises copper at a molar ratio of about 0.5 to about 10, about 1 to about 10, about 0.5 to about 5, about 0.5 to about 2, about 1 to about 5, about 2 to about 9, about 2 to about 6, about 2 to about 4, or about 2.3 to about 8.4 relative to the one or more first elements.

In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.3 to about 3, about 1 to about 2.5, or about 0.4 to about 1, relative to copper.

The reduction catalyst may comprise the one or more Group IA or IIA metals. In some embodiments, the one or more Group IA or IIA metals comprise magnesium, calcium, potassium, sodium, or cesium. In some embodiments, the one or more Group IA or IIA metals consist of magnesium, calcium, potassium, sodium, or cesium. In certain embodiments, the one or more Group IA or IIA metals comprise or consist of sodium and/or cesium. In some embodiments, the reduction catalyst comprises one or more Group IA metals. The one or more Group IA or IIA metals may comprise potassium, sodium or cesium. In some embodiments, the one or more Group IA or IIA metals consist of potassium, sodium or cesium. In some embodiments, the one or more Group IA or IIA metals comprise potassium. In some embodiments, the one or more Group IA or IIA metals comprise sodium. In some embodiments, the one or more Group IA or IIA metals comprise cesium.

In some embodiments, the reduction catalyst comprises potassium at a molar ratio of about 0.05 to about 0.5, about 0.05 to about 0.1, about 0.09 to about 0.4, about 0.1 to about 0.3, or about 0.08 to about 1.0 relative to copper.

In some embodiments, the reduction catalyst comprises aluminum at a molar ratio of about 0.1 to about 10, about 0.1 to about 1, about 0.1 to about 0.2, about 0.5 to about 1 relative to copper.

The reduction catalyst may comprise one or more metal oxides selected from the group consisting of: zinc oxide, copper oxide, cobalt oxide, iron oxide, nickel oxide, and any combination thereof. The reduction catalyst may comprise alumina.

In some embodiments, the reduction catalyst comprises aluminum oxide (Al₂O₃) wherein the aluminum is present in a molar ratio of about 0.01 to about 100, about 0.1 to about 0.8, about 10 to about 50, about 30 to about 50, about 30 to about 80, about 10 to about 80, or about 5 to about 20 relative to copper. In some embodiments, the alumina can be added as a support to increase the surface area of the copper and zinc, or produced in-situ as a component of the reduction catalyst, e.g. from aluminum nitrate co-precipitation with first element, copper, and zinc precursors.

In some embodiments, the reduction catalyst comprises copper, zinc oxide, cobalt, and alumina. In some embodiments, the reduction catalyst comprises copper, zinc oxide, nickel, and alumina. In some embodiments, the reduction catalyst comprises copper, zinc oxide, iron, and alumina. In some embodiments, the reduction catalyst comprises copper, zinc oxide, cobalt, alumina, and a Group IA metal. In some embodiments, the reduction catalyst comprises copper, zinc oxide, nickel, alumina, and a Group IA metal. In some embodiments, the reduction catalyst comprises copper, zinc oxide, iron, alumina, and a Group IA metal. The molar ratios of the foregoing components may be as described above.

The reduction catalyst may comprise Cu, Zn, Al, and O. The reduction catalyst may comprise Cu, Zn, Al, O, and an alkali metal, and optionally also comprise Ni, Fe, Co, Nb, Mo, In, Se, or any combination thereof.

The elemental composition of the reduction catalyst material may be Cu(ZnO)CoA/Al₂O₃, Cu(ZnO)CoFeA/Al₂O₃, Cu(ZnO)CoNbA/Al₂O₃, Cu(ZnO)CoNiA/Al₂O₃, Cu(ZnO)CoMoA/Al₂O₃ wherein A is an alkali metal and further wherein the relative amounts of the elemental components are as described above. The elemental composition of the reduction catalyst material may be Cu(ZnO)Co/Al₂O₃, Cu(ZnO)CoFe/Al₂O₃, Cu(ZnO)CoNb/Al₂O₃, Cu(ZnO)CoNi/Al₂O₃, Cu(ZnO)CoMo/Al₂O₃, wherein the relative amounts of the elemental components are as described above. The elemental composition of the reduction catalyst material may be CuO(ZnO), Cu(ZnO)Co, Cu(ZnO)CoK, Cu(ZnO)CoFe, Cu(ZnO)CoFeK, Cu(ZnO)CoNi, Cu(ZnO)CoNiK, Cu(ZnO)CoNb, Cu(ZnO)CoNbK, Cu(ZnO)CoMo, Cu(ZnO)CoMoK on Al₂O₃, wherein the relative amounts of the elemental components are as described above.

In further aspects, provided herein are reduction catalysts comprising:

• • one or more metals;
  • optionally one or more second elements selected from copper and zinc;
  • optionally one or more Group VI, VII, VIII, IX, X, or XI metal additives;
  • optionally a Group IA or IIA metal, which acts as a promoter.

The one or more metals may be selected from cobalt, iron, nickel, indium, yttrium, a lanthanide, and combinations thereof. In certain embodiments, the one or more metals is cobalt. In other embodiments, the one or more metals is iron. In still further embodiments, the one or more metals is a combination of iron and cobalt.

The one or more metals may be present in the form of an oxide, nitride, or carbide. In certain embodiments, the one or more metals is present in the form of an iron oxide.

In further embodiments, the one or more second elements is copper. In yet further embodiments, the one or more second elements is zinc. In still further embodiments, the one or more second elements are copper and zinc. In certain embodiments, the one or more second elements is present in the form of an oxide, nitride, or carbide. In yet further embodiments, the one or more second elements is zinc oxide.

In certain embodiments, the one or more Group VI, VII, VIII, IX, X, or XI metal additives, when present, is selected from manganese, silver, niobium, zirconium, molybdenum, ruthenium, palladium, platinum, or nickel. In further embodiments, the Group IA or IIA metal, when present, are Group IA elements. In yet further embodiments, the one or more Group IA or IIA metals, when present, are magnesium, calcium, lithium, sodium, potassium, or cesium. In yet further embodiments, the Group IA or IIA metal, when present, is lithium, sodium, potassium, or cesium. In still further embodiments, the one or more second elements is present in an amount of about 0.5 to about 40 wt. % of the total amount of the one or more metals, the second element, the optional one or more Group VI, VII, VIII, IX, X, or XI metal additives, and the optional Group IA or IIA metal.

In some embodiments, the reduction catalyst comprises one or more Group VI or VII metals, such as manganese (Mn), Chromium (Cr), or a combination thereof. In some embodiments, the reduction catalyst comprises the one or more Group VI or VII metals at a molar ratio from about 0.01 to about 1.0, about 0.05 to about 0.50, about 0.1 to about 0.2, about 0.20 to about 0.50, about 0.30 to about 0.50, about 0.40 to about 0.50 relative to copper or cobalt.

In certain aspects, the reduction catalyst comprises: one or more paraffin metal oxides; optionally a support, and optionally one or more metal additives. The one or more paraffin metal oxides may be selected from cobalt oxide, iron oxide, nickel oxide, indium oxide, yttrium oxide, a lanthanide oxide, and combinations thereof. The support, when present, may comprise carbon, silica, zeolite, alumina, zirconium oxide, titanium oxide, or silica carbide. The one or more metal additives, when present, may be selected from a Group IA or IIA element, palladium, platinum, ruthenium, or combinations thereof.

In certain aspects, the present disclosure provides catalytic compositions, comprising one or more of reduction catalyst and a reduction catalyst support. The reduction catalyst support may be any suitable material that can serve as a catalyst support.

The reduction catalyst support may comprise one or more materials selected from an oxide, nitride, fluoride, silicate, or carbide of an element selected from aluminum, silicon, titanium, zirconium, cerium, magnesium, yttrium, lanthanum, zinc, tungsten, and tin. In some embodiments, the reduction catalyst support comprises γ-alumina. In certain embodiments, the reduction catalyst support is selected from carbon, silica, zeolite, alumina, zirconium oxide, titanium oxide, and silica carbide. In some embodiments, the reduction catalyst support is selected from alumina (e.g., γ-alumina), boehmite, crystalline boehmite, pseudoboehmite, gibbsites, and thermally shocked gibbsites. In some embodiments, the reduction catalyst support is an aluminum oxide that is formed in-situ as part of the reduction catalyst. In some embodiments, the reduction catalyst support is selected from, but not limited to, MgO, Al₂O₃, ZrO₂, SnO₂, SiO₂, ZnO, WO₃, and TiO₂. In some embodiments, the reduction catalyst support is selected from MgO, Al₂O₃, ZrO₂, SnO₂, SiO₂, ZnO, WO₃, silica carbide, and TiO₂.

In some embodiments, the reduction catalyst support comprises one or more carbon-based materials. In some embodiments, the carbon-based material is selected from activated carbon, carbon nanotubes, graphene, and graphene oxide.

In some embodiments, the reduction catalyst support is selected from SiAlO_x, SO₄—ZrO₂, zirconium tungstate, tungstated-titania, and anatases (SiO₂—Al₂O₃, SiO₂—TiO₂). In further embodiments, the reduction catalyst support is an aluminum-based material such as alumina (e.g., γ-alumina), boehmite, crystalline boehmite, pseudoboehmite, gibbsites, and thermally shocked gibbsites.

In some embodiments, the reduction catalyst support is a zeolite such as Y-type zeolites, beta-zeolites, ZSM-type zeolites (e.g., ZSM-5, HZSM-5, ZSM-12, ZSM-22, ZSM-57), SAPO type zeolites (e.g., SAPO11, SAPO31, SAPO41), L zeolite (LTL), mordenite zeolites, MCM-49, MCM-22, DA-114, microcrystalline USY zeolite, microcrystalline USY zeolite, and combinations thereof. In certain embodiments, the reduction catalyst support is MCM-49. In further embodiments, the zeolites comprise additional metals such as Zn, Ga, Fe, or other transition metals. In yet further embodiments, the additional metals are present as zeolite supported metals or as isomorphous substitution in the zeolite framework.

In some embodiments, the reduction catalyst support is modified with molybdenum, chlorine, and/or sulfur.

In some embodiments, the support is a high surface area scaffold. In some embodiments, the support comprises carbon allotropes. In some embodiments, the support comprises mesoporous material, such as mesoporous silica. In such embodiments, as will be appreciated by one of ordinary skill in the art, the physical characteristics of the mesoporous material, e.g., mesopore volume and surface area may be measured using standard gas absorption measurement techniques known in the art including, for example, the Barrett-Joyner-Halenda (BJH) method for determining pore size distributions and pore volumes, and the Brunauer, Emmett and Teller (BET) method for obtaining the specific surface area (hereinafter “surface area”).

In some embodiments, the reduction catalyst support has a mesopore volume from about 0.01 to about 3.0 cc/g.

In some embodiments, the reduction catalyst support has surface area from about 10 m²/g to about 1000 m²/g. In some embodiments, the catalytic composition comprising the reduction catalyst support and a catalyst disclosed herein has a surface area from about 10 m²/g to about 1000 m²/g.

The catalytic composition may be in a form of particles having an average size from about 10 nm to about 5 μm, an average size from about 20 nm to about 5 μm, an average size from about 50 nm to about 1 μm, an average size from about 100 nm to about 500 nm, or an average size from about 50 nm to about 300 nm.

The catalytic composition may comprise about 5 wt. % to about 80 wt. %, about 5 wt. % to about 70 wt. %, about 20 wt. % to about 70 wt. %, or about 30 wt. % to about 70 wt. % of the reduction catalyst.

In some embodiments, the reduction catalyst is a nanoparticle catalyst. The particle sizes of the reduction catalyst on the surface of the scaffold may be about 1 nm to about 5 nm, about 5 nm to about 100 nm, or about 100 to about 500 nm. In some embodiments, the particles not subjected to agglomeration are about 100 nm to about 500 nm in particle size.

The reduction catalyst may comprise: iron; optionally alumina; optionally a first element selected from copper, zinc, cobalt, manganese, chromium, or combinations thereof; and optionally one or more second elements selected from Group IA and IIA metals.

In certain embodiments, the reduction catalyst further comprises an additive mixture comprising potassium, manganese, ruthenium, and MgO. In further embodiments, the reduction catalyst comprises from about 1% to about 10% by weight of the additive mixture.

The reduction catalyst may comprise a first element selected from copper, zinc, cobalt, or combinations thereof. The first element may be copper. The first element may be zinc. The first element may be cobalt. The first element may be a combination of copper, zinc, and/or cobalt.

The reduction catalyst may comprise one or more Group IA or IIA metals. The one or more Group IA or IIA metals may comprise magnesium, calcium, potassium, sodium, or cesium. The one or more Group IA or IIA metals may consist of magnesium, calcium, potassium, sodium or cesium. The one or more Group IA or IIA metals may comprise magnesium. The one or more Group IA or IIA metals may comprise calcium. The one or more Group IA or IIA metals may comprise potassium. The one or more Group IA or IIA metals may comprise sodium. The one or more Group IA or IIA metals may comprise cesium. The one or more Group IA or IIA metals may consist of magnesium. The one or more Group IA or IIA metals may consist of calcium. The one or more Group IA or IIA metals may consist of potassium. The one or more Group IA or IIA metals may consist of sodium. The one or more Group IA or IIA metals may consist of cesium.

The reduction catalyst may comprise: iron; a first element selected from K, Li, Zr, Cs, Mg, Rh, Ca, or a combination thereof; one or more second elements selected from Au, Cu, Na, Cr, Al, Ga, Mn Co, Ru, Ni, or a combination thereof; and optionally alumina.

The reduction catalyst may comprise: iron; K, Li, Zr, Cs, Mg, Rh, Ca, or a combination thereof, at a molar ratio of from 0 to about 0.20 relative to iron; Au, Cu, Na, Cr, Al, Ga, Mn, or a combination thereof, at a molar ratio from 0 to about 0.60 relative to iron; and Zn at a molar ratio from 0 to about 0.50 relative to iron.

In certain embodiments, the catalyst comprises K at a molar ratio of from 0 to about 0.20 relative to iron, and/or Na at a molar ratio from 0 to about 0.60 relative to iron.

In certain embodiments, the reduction catalyst comprises: iron; K, Cs, Mg, Rh, Ca, or a combination thereof, at a molar ratio of from 0 to about 0.20 relative to iron; Na, Cu, Cr, Mn, or a combination thereof, at a molar ratio of from 0 to about 0.60 relative to iron; Co, Ru, Ni, or a combination thereof, at a molar ratio of from 0 to about 0.50 relative to iron.

In some embodiments, the reduction catalyst comprises Co at a molar ratio of from 0 to about 0.50, or about 0.1 to about 0.2 relative to iron. In certain embodiments, the reduction catalyst comprises Co at a molar ratio of about 0.14 relative to iron, and K at a molar ratio of about 0.01 relative to iron.

The iron may be in metal form, in the form of an iron oxide, or a combination thereof. In certain embodiments, the iron is in the iron oxide form. The iron oxide may be FeO, magnetite (Fe₃O₄), hematite (Fe₂O₃), or a combination thereof. In some embodiments, the iron oxide is magnetite (Fe₃O₄). In other embodiments, the iron oxide is a combination of magnetite (Fe₃O₄) and hematite (Fe₂O₃). In other embodiments, the iron oxide is a combination of FeO, magnetite (Fe₃O₄) and hematite (Fe₂O₃).

The reduction catalyst may comprise: iron; a first element selected from copper, zinc, cobalt, or combinations thereof; and optionally one or more second elements selected from Group IA and IIA metals.

The reduction catalyst may also include one or more third elements selected from a Group V, VI, VII, VIII, IX, X, and XI metal (e.g., manganese, chromium, silver, niobium, zirconium, molybdenum, ruthenium, palladium, platinum, or nickel).

The reduction catalyst may include: iron; and the first element being zinc. One or both of the iron and zinc may be present in oxide or carbide forms. The iron oxide may be in the form of FeO, Fe₂O₃ (hematite), Fe₃O₄ (magnetite) or a combination thereof. The iron oxide may be substantially (e.g., over about 80%, or over about 90%) in the form of Fe₂O₃. The iron oxide may be substantially (e.g., over about 80%, or over about 90%) in the form of Fe₃O₄.

The reduction catalyst may comprise zinc at a molar ratio of about 0.2 to about 3 relative to iron, or about 0.3 to about 3 relative to iron. In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.2 to about 1 relative to iron, or about 0.4 to about 1 relative to iron. In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 1.5 relative to iron. In other embodiments, the reduction catalyst comprises zinc at a molar ratio of about 1.0 relative to iron. In certain embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.75 relative to iron, about 0.6 relative to iron, about 0.5 relative to iron, about 0.4 relative to iron, about 0.3 relative to iron, or about 0.25 relative to iron. In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.5 relative to iron.

The reduction catalyst may comprise a molar ratio of iron to zinc of about 1:1 to about 7:1, about 1:1 to about 6:1; about 2:2 to about 6:1, about 1:1 to about 4:1, about 1:1 to about 3:1, or about 2:1 to about 3:1. The reduction catalyst may comprise a molar ratio of iron to zinc of about 1:1 to about 4.5:1, about 1.5:1 to about 3.5:1, about 1.5:1 to about 3:1, or about 1.5:1 to about 2.5:1. The reduction catalyst may comprise a molar ratio of iron to zinc of about 2:1.

In some embodiments, the reduction catalyst comprises: iron; zinc at a molar ratio of about 0.2 to about 3 relative to iron; and one or more Group IA or IIA metals.

The one or more Group IA or IIA metals may be present at a molar ratio from 0 to about 0.60 relative to iron; and Zn at a molar ratio from 0 to about 0.50 relative to iron.

The reduction catalyst may comprise K, Na, Cs, Rh, or a combination thereof at a molar ratio of about 0.01 to about 0.20, about 0.01 to about 0.10, about 0.01 to about 0.08, about 0.01 to about 0.05, or about 0.02 to about 0.4 relative to iron. In other embodiments, the reduction catalyst comprises Na at a molar ratio of about 0.01 to about 0.20, about 0.01 to about 0.10, about 0.01 to about 0.08, about 0.01 to about 0.05, or about 0.02 to about 0.4 relative to iron.

The reduction catalyst may comprise K, Na, Cs, Rh, or a combination thereof in an amount of about 0.2% to about 1.5%, or about 0.5% to about 1.0% of the total weight of iron plus the first element. In certain embodiments, the reduction catalyst comprises Na in an amount of about 0.2% to about 1.5%, or about 0.5% to about 1.0% of the total weight of iron plus the first element. In other embodiments when the first element is zinc, the reduction catalyst may comprise Na in an amount of about 0.2% to about 1.5%, or about 0.5% to about 1.0% of the total weight of iron plus zinc.

The reduction catalyst may afford a product stream having a methane selectivity of less than about 11 carbon mole %, or less than about 10 carbon mole %. The olefin catalyst may afford a product stream having a methane selectivity of about 4 carbon mole % to about 11 carbon mole %, or about 5 carbon mole % to about 10 carbon mole %. Unless specifically identified otherwise, selectivity values disclosed herein are in carbon mole %.

The reduction catalyst may afford a product stream having an olefin to paraffin ratio (O/P) of greater than about 7. The reduction catalyst may afford a product stream having an olefin to paraffin ratio (O/P) of about 7 to about 9, about 8 to about 9, or about 8.

In certain aspects, the reduction catalyst further comprise a reduction catalyst support. The reduction catalyst support may be any suitable material that can serve as a catalyst support, or any reduction catalyst support disclosed above.

In certain embodiments, the reduction catalyst comprising the reduction catalyst support is in a form of particles having an average size from about 10 nm to about 5 μm, about 20 nm to about 5 μm, about 50 nm to about 1 μm, about 100 nm to about 500 nm, or about 50 nm to about 300 nm.

In certain embodiments, the reduction catalyst comprising the reduction catalyst support comprises from about 5 wt. % to about 80 wt. %, about 5 wt. % to about 70 wt. %, about 20 wt. % to about 70 wt. %, or about 30 wt. % to about 70 wt. % of the reduction catalyst.

In certain embodiments, the reduction catalyst support is a high surface area scaffold. In further embodiments, the reduction catalyst support comprises mesoporous silica. In yet further embodiments, the reduction catalyst support comprises carbon allotropes.

In certain embodiments, the reduction catalyst is pretreated with syngas. In yet further embodiments, the reduction catalyst is pretreated with hydrogen. In still further embodiments, the reduction catalyst is heated with inert gas (including but not limited to nitrogen gas, argon) before the production.

Reduction catalysts disclosed herein have improved selectivity for olefins and/or paraffins over methane and improved means for adjusting the olefin to paraffin ratio.

By using a reduction catalyst disclosed herein with carbon conversion, a carbon source gas may be converted into a hydrocarbon mixture comprising olefins and paraffins. The hydrocarbon mixture may have an olefin to paraffin ratio (O/P) of greater than about 7. The reduction catalyst may afford a product stream having an olefin to paraffin ratio (O/P) of about 7 to about 9, about 8 to about 9, or about 8.

Methane is generally an undesirable byproduct of carbon dioxide conversion. Methane production is therefore a factor of the effectiveness of the catalyst, as methane production is undesirable. Accordingly, the lower the methane production (also referred to herein as methane selectivity, SCI, defined in Equation 1), the better the catalyst. Referring to Equation 1, Cmol.CH₄ represents mole fraction of methane in the product stream, Cmol.CO_2feed represents mole fraction of CO₂ in the feed stream, and Cmol.CO_2product represents the mole fraction of CO₂ in the product stream.

Selectivity ⁢ for ⁢ methane ⁢ ( SC 1 ) =  [ Cmol · CH 4 / ( Cmol · CO 2 ⁢ feed - Cmol · CO 2 ⁢ product ) ] Eq . 1

The reduction catalyst disclosed herein may have a methane selectivity (SC₁) of less than about 15, less than about 11, or less than about 10 carbon mole %. The reduction catalyst may have a methane selectivity of about 2 to about 15, about 4 to about 15, about 5 to about 12, about 5 to about 11, about 6 to about 11, or about 8 to about 11 carbon mole %. The reduction catalysts described herein may have a selectivity for C₂ to C₄ hydrocarbons (SC₂—C₄) of greater than about 15, greater than about 20, greater than about 25, greater than about 30, greater than about 35, or greater than about 35 carbon mole %. The reduction catalysts described herein may have a SC₂—C₄ from about 15 to about 50, about 20 to about 45, or about 25 to about 45 carbon mole %. The reduction catalysts described herein may have a SC₂—C₄ of about 28, about 35, about 38, about 39, or about 45 carbon mole %. The selectivity for C_2-4 is determined by adding (selectivity for C₂)+(selectivity for C₃)+(selectivity for C₄), with each selectivity value calculated according to Equation 2. Referring to Equation 2: C_x represents a hydrocarbon having a carbon number of x; Cmol.C_x represents mole fraction of C_x in the product stream; Cmol.CO_2feed represents mole fraction of CO₂ in the feed stream; and Cmol.CO_2product represents the mole fraction of CO₂ in the product stream.

Selectivity ⁢ for ⁢ hydrocarbon ⁢ C x ⁢ ( SC x ) =  [ Cmol · C x / ( Cmol · CO 2 ⁢ feed - Cmol · CO 2 ⁢ product ) ] Eq . 2

The reduction catalysts disclosed herein may have a selectivity for C₅₊ hydrocarbons (SC₅₊, wherein C₅₊ refers to any hydrocarbons with a carbon number of 5 or higher) of greater than about 20, greater than about 22, greater than about 25, greater than about 28, greater than about 30, greater than about 32, or greater than about 34 carbon mole %. The reduction catalysts disclosed herein may have a selectivity for C₅₊ hydrocarbons (SC₅₊) from about 20 to about 45, about 22 to about 43, about 25 to about 43, about 28 to about 43, or about 30 to about 40 carbon mole %. The reduction catalysts disclosed herein may have a selectivity for C₅₊ hydrocarbons (SC₅₊) of about 29, about 31, about 33, about 34, about 35, or about 43 carbon mole %. The higher the selectivity for C₅₊ hydrocarbons, the better the catalyst performance for the processes of carbon dioxide conversion disclosed herein.

Oxygenates are generally an undesirable byproduct of carbon dioxide conversion. The reduction catalyst disclosed herein may have an oxygenate selectivity (Soxy) of less than about 20, less than about 16, less than about 14, or less than about 15 carbon mole %. The reduction catalyst may have an oxygenate selectivity of about 2 to about 20, about 4 to about 18, or about 4 to about 16 carbon mole %.

Metal leaching can be a problem associated with the use of metal-containing catalysts. Metal leaching of the catalysts can cause a number of problems, including: i) Product contamination: metal ions from the catalyst can dissolve into liquids, which can contaminate the product stream, and may require significant downstream processing to remove the metals; ii) System corrosion: metal leaching can cause corrosion in the system; and iii) Catalyst deactivation: metal leaching can cause the loss of active species from the catalyst and loss of efficacy, in terms of activity and selectivity. The higher the rate of leaching, the faster the deactivation of the catalyst.

Reduction catalysts of the disclosure provide significant improvements in metal leaching over other catalysts, including unsupported metal catalysts. The formed reduction catalysts (that is, the catalyst including the binder) disclosed herein have a significant reduction in metal leaching over the powder form of the same catalyst (i.e., without the binder). The amount of metal leaching when comparing the powder catalyst to a formed catalyst may be decreased by over about 50%, over about 70%, over about 80%, or over about 90%.

The amount of total metal leaching in the effluent may be measured once the reaction has reached a steady state by: i) separating the aqueous portion from the oil portion of the effluent; and ii) analyzing a sample of the aqueous portion by ICP-MS to obtain a concentration of metal leached in the aqueous sample. The method of measuring metal leaching may further include: iii) dissolving the oil portion in an acid, such as nitrohydrochloric acid; iv) analyzing a sample of the dissolved oil portion by ICP-MS to obtain a concentration of metal in the oil sample; and v) adding the concentration of metal in the oil sample and the concentration of metal in the aqueous sample to obtain the total metal leaching. After steady state has been reached the oil sample generally includes less than about 1 ppm of leached metal. Before steady state has been reached, the loose powder in the catalyst migrates into the effluent and dissolves in the oil portion of the effluent and may be tested if warranted. As the time on stream continues, the loose powder in the catalyst is eliminated and thus the concentration of metal in the oil portion of the effluent reduces to zero.

Steady state of the reaction may be reached after a time on stream that results in the concentration (ppm) of the second element being about 10 ppm or less, about 8 or less, or about 6 ppm or less. Steady state of the reaction may be reached after a time on stream that results in the concentration (ppm) of the second element being about 0 ppm to about 10 ppm, about 0 ppm to about 8 ppm, about 0 ppm to about 6 ppm, or greater than about 0 ppm to about 6 ppm. Steady state may be reached after about 100 hours to about 1000 hours, about 200 hours to about 800 hours, about 200 hours to about 600 hours time on stream. Steady state of the reaction may be determined by the concentration of the second element because the second element leaches more than the active metals and is in the lower amount in the catalyst than the active metals. a. When the reduction catalyst is contacted with a continuous flow of fluid, the total concentration of iron, zinc, and one or more second elements in the effluent at steady state may be less than about 50 ppm, less than about 40 ppm, less than about 20 ppm, or less than about 15 ppm. The total concentration of iron, zinc, and one or more second elements in the effluent at steady state may be less than about 50 ppm, less than about 40 ppm, less than about 20 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm. The total concentration of iron, zinc, and one or more second elements in the effluent tested at steady state may be about 0 ppm to about 50 ppm, greater than about 0 ppm to about 40 ppm, about 1 ppm to about 30 ppm, or about 1 ppm to about 20 ppm. The total concentration of iron, zinc, and one or more second elements may also be understood as the metal leaching in the reactor effluent stream tested after an amount of time on stream, or at steady state.

The total concentration of the one or more second elements in the effluent at steady state may be less than about 10 ppm, less than about 8 ppm, less than about 6 ppm, less than about 5 ppm, less than about 4 ppm, less than about 3 ppm, or less than about 2 ppm. The total concentration of the one or more second elements in the effluent tested at steady state may be about 0 ppm to about 10 ppm, about 0 ppm to about 8 ppm, about 0 ppm to about 6 ppm, or greater than about 0 ppm to about 6 ppm. When the second element is sodium, the total concentration of sodium, also understood as the concentration of sodium leached from the formed catalyst, in the effluent at steady state may be less than about 6 ppm, less than about 5 ppm, less than about 4 ppm, less than about 3 ppm, or less than about 2 ppm. The total concentration of sodium in the effluent tested at steady state may be about 0 ppm to about 6 ppm, or greater than about 0 ppm to about 6 ppm.

The total concentration of iron, zinc, and one or more second elements in the effluent tested after about 200 hrs to about 400 hrs of time on stream may be less than about 50 ppm, less than about 40 ppm, less than about 20 ppm, or less than about 15 ppm. The total concentration of iron, zinc, and one or more second elements in the effluent tested after about 400 hrs of time on stream may be less than about 50 ppm, less than about 40 ppm, less than about 20 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm. The total concentration of iron, zinc, and one or more second elements in the effluent tested after about 400 hrs of time on stream may be about 0 ppm to about 50 ppm, greater than about 0 ppm to about 40 ppm, about 1 ppm to about 30 ppm, or about 1 ppm to about 20 ppm. The total concentration of iron, zinc, and one or more second elements in the effluent tested after about 200 hrs of time on stream may be less than about 50 ppm, less than about 40 ppm, less than about 20 ppm, or less than about 15 ppm. The total concentration of iron, zinc, and one or more second elements in the effluent tested after about 200 hrs of time on stream may be about 0 ppm to about 50 ppm, about 1 ppm to about 40 ppm, about 1 ppm to about 20 ppm, or about 1 ppm to about 15 ppm. Metal leaching refers to the total amount (i.e., concentration) of iron, zinc and the second element selected from Group IA, IIA, and/or X metal ions present in the effluent tested after an amount of time on stream.

Because there may be less of the second element present in the catalyst than iron or zinc, reducing the leaching of the second element may be especially important in maintaining the life of the catalyst. The amount of leaching of the second element (e.g., Na, K) of the formed catalyst in the effluent tested after about 200 hrs to about 400 hrs of time on stream may be less than about 10 ppm, less than about 8 ppm, less than about 5 ppm, or less than about 2 ppm. The amount of leaching of the second element of the formed catalyst in the effluent tested after about 400 hrs of time on stream may be less than about 10 ppm, less than about 8 ppm, less than about 5 ppm, or less than about 2 ppm. The amount of leaching of the second element of the formed catalyst in the effluent tested after about 400 hrs of time on stream may be about 0 ppm to about 10 ppm, about 0 ppm to about 8 ppm, about 0 ppm to about 6 ppm, about 0.1 ppm to about 5 ppm, or about 1 ppm to about 4 ppm.

The amount of leaching of the second element of the formed catalyst in the effluent tested after about 200 hrs of time on stream may be less than about 10 ppm, less than about 8 ppm, less than about 5 ppm, or less than about 4 ppm. The amount of leaching of the second element of the formed catalyst in the effluent tested after about 200 hrs of time on stream may be about 1 ppm to about 10 ppm, about 1 ppm to about 8 ppm, about 1 ppm to about 5 ppm, or about 1 ppm to about 4 ppm.

The formed reduction catalyst referred to herein contains a binder and shape formed by any known means in the art, for example but not limited to, extrusion, press, powder pressed to pellets, tablets or other shaped forms. The formed catalyst (as extrudate or pellet) may have a crush strength greater than about 20 N/mm, greater than about 25 N/mm, greater than about 30 N/mm or greater than about 40 N/mm. The formed catalyst (as extrudate, pellet, or tablet) may have a crush strength of about 20 N/mm to about 100 N/mm, about 20 N/mm to about 80 N/mm, about 20 N/mm to about 65 N/mm, about 30 N/mm to about 65 N/mm, about 35 N/mm to about 60 N/mm, or about 40 N/mm to about 55 N/mm.

Due to the reduced metal leaching, the reduction catalyst disclosed herein have a longer life (i.e., before deactivation) than other catalysts. The reduction catalyst disclosed herein may maintain activity for over about one year, over about 18 months, over about 20 months, over about 36 months, or over about 48 months. The reduction catalyst disclosed herein may maintain activity for about one year to about 5 years, about two years to about 5 years, about 3 years to about 5 years, or about 4 years to about 5 years. The term “maintain activity” means that the activity of the catalyst in conversion of CO₂ to hydrocarbons remains above about 75% of its initial activity.

The product stream may comprise C₁-C₄₀ hydrocarbons. The C₁-C₄₀ hydrocarbons of the product stream may comprise (1) paraffins (n-paraffins, iso-paraffins, cyclo-paraffins), olefins (n-olefins, iso-olefins), and (2) aromatics. The product stream may also comprise: (3) oxygenates (alcohols, ketones, esters, aldehydes and acids), and (4) water.

The feed stream may comprise a carbon source gas, e.g., CO₂, and a reduction gas, e.g., H₂, IN certain embodiments, the feed stream may further comprise one or more of the following: CO, CH₄, C₂H₄, C₂H₆, C₃H₆, C₃H₈, C₄H₈, C₄H₁₀.

The reduction catalyst may comprise iron and zinc, one or more second elements selected from Group IA, IIA, and X metals, and a binder. When the reduction catalyst includes a binder, it may also be referred to as a formed reduction catalyst. The reduction catalyst may comprise iron and zinc; optionally alumina; optionally a first element selected from copper, cobalt, manganese, chromium, or combinations thereof; optionally one or more second elements selected from Group IA, IIA, and X metals; and a binder

The reduction catalyst may comprise a first element selected from copper, cobalt, or combinations thereof. The first element may be copper. The first element may be cobalt. The first element may be a combination of copper, and/or cobalt. The reduction catalyst may be free of a first element selected from copper, cobalt, or combinations thereof.

The reduction catalyst may comprise the second element selected from one or more Group IA or IIA metals. The one or more Group IA or IIA metals may comprise magnesium, calcium, potassium, sodium, cesium, rubidium, or any combination thereof. The one or more Group IA or IIA metals may consist of magnesium, calcium, potassium, sodium, cesium, or rubidium. The one or more Group IA or IIA metals may comprise magnesium. The one or more Group IA or IIA metals may comprise calcium. The one or more Group IA or IIA metals may comprise potassium. The one or more Group IA or IIA metals may comprise sodium. The one or more Group IA or IIA metals may comprise cesium. The one or more Group IA or IIA metals may comprise rubidium. The one or more Group IA or IIA metals may consist of magnesium. The one or more Group IA or IIA metals may consist of calcium. The one or more Group IA or IIA metals may consist of potassium. The one or more Group IA or IIA metals may consist of sodium. The one or more Group IA or IIA metals may consist of cesium. The one or more Group IA or IIA metals may consist of rubidium.

The reduction catalyst may comprise the second element being a Group X metal. The Group X metal may be selected from palladium, platinum, iridium, nickel, and rhodium. The Group X metal may be platinum. The Group X metal may be palladium. The Group X metal may be nickel.

The reduction catalyst may also include one or more third elements selected from a Group V, VI, VII, VIII, IX, and XI metal (e.g., manganese, chromium, silver, niobium, zirconium, molybdenum, ruthenium). The reduction catalyst may include manganese. The reduction catalyst may include silver. The reduction catalyst may be free of a third element selected from a Group V, VI, VII, VIII, IX, and XI metal

The reduction catalyst may comprise the Group IA, IIA, or X metal at about 0.1 wt % to about 60 wt % of the total weight of iron, zinc, and Group IA, IIA, or X metal. The reduction catalyst may comprise the Group IA, IIA, or X metal at about 0.1 wt % to about 20 wt %, about 0.1 wt % to about 10 wt %, about 0.1 wt % to about 5 wt %, about 0.1 wt % to about 2 wt %, about 0.4 wt % to about 1.5 wt %, or about 0.5 wt % to about 1.5 wt % of the total weight of iron, zinc, and Group IA, IIA, or X metal. The reduction catalyst may comprise a Group IA metal at about 0.1 wt % to about 60 wt % of the total weight of iron, zinc, and Group IA metal. The reduction catalyst may comprise the Group IA metal at about 0.1 wt % to about 20 wt %, about 0.1 wt % to about 10 wt %, about 0.1 wt % to about 5 wt %, about 0.1 wt % to about 2 wt %, about 0.4 wt % to about 1.5 wt %, or about 0.5 wt % to about 1.5 wt % of the total weight of iron, zinc, and Group IA metal.

The reduction catalyst may comprise Na, Mn, K, Cs, Li, Rb at a molar ratio from 0 to about 0.60 relative to iron. In certain embodiments, the reduction catalyst comprises: iron; K, Cs, Mg, Rh, Ca, or a combination thereof, at a molar ratio of from 0 to about 0.20 relative to iron; Na, Cu, Cr, Mn, or a combination thereof, at a molar ratio of from 0 to about 0.60 relative to iron; and/or Co, Ru, Ni, or a combination thereof, at a molar ratio of from 0 to about 0.50 relative to iron.

The iron may be in metal form, in the form of an iron oxide, or a combination thereof. In certain embodiments, the iron is in the iron oxide form. The iron oxide may be FeO, magnetite (Fe₃O₄), hematite (Fe₂O₃), or a combination thereof. In some embodiments, the iron oxide is magnetite (Fe₃O₄). In other embodiments, the iron oxide is a combination of magnetite (Fe₃O₄) and hematite (Fe₂O₃). In other embodiments, the iron oxide is a combination of FeO, magnetite (Fe₃O₄) and hematite (Fe₂O₃).

The reduction catalyst may include: iron and zinc, with one or both of the iron and zinc being present in oxide or carbide forms. The iron oxide may be in the form of FeO, Fe₂O₃ (hematite), Fe₃O₄ (magnetite) or a combination thereof. The iron oxide may be substantially (e.g., over about 80%, or over about 90%) in the form of Fe₂O₃. The iron oxide may be substantially (e.g., over about 80%, or over about 90%) in the form of Fe₃O₄. The reduction catalyst may comprise zinc at a molar ratio of about 0.2 to about 3 relative to iron, or about 0.3 to about 3 relative to iron. In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.2 to about 1 relative to iron, or about 0.4 to about 1 relative to iron. In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 1.5 relative to iron. In other embodiments, the reduction catalyst comprises zinc at a molar ratio of about 1.0 relative to iron. In certain embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.75 relative to iron, about 0.6 relative to iron, about 0.5 relative to iron, about 0.4 relative to iron, about 0.3 relative to iron, or about 0.25 relative to iron. In some embodiments, the reduction catalyst comprises zinc at a molar ratio of about 0.5 relative to iron.

The reduction catalyst may comprise a molar ratio of iron to zinc of about 1:1 to about 7:1, about 1:1 to about 6:1; about 2:2 to about 6:1, about 1:1 to about 4:1, about 1:1 to about 3:1, or about 2:1 to about 3:1. The reduction catalyst may comprise a molar ratio of iron to zinc of about 1:1 to about 4.5:1, about 1.5:1 to about 3.5:1, about 1.5:1 to about 3:1, or about 1.5:1 to about 2.5:1. The reduction catalyst may comprise a molar ratio of iron to zinc of about 2:1.

In some embodiments, the reduction catalyst comprises: iron; zinc at a molar ratio of about 0.2 to about 6 relative to iron; and one or more Group IA and IIA metals. The one or more Group IA and IIA metals may be present at a molar ratio from 0 to about 0.60 relative to iron; and Zn at a molar ratio from 0 to about 0.50 relative to iron. In some embodiments, the reduction catalyst comprises: iron; zinc at a molar ratio of about 0.2 to about 6 relative to iron; and one or more Group IA, IIA, and X metals. The one or more Group IA, IIA, and X metals may be present at a molar ratio from 0 to about 0.60 relative to iron; and Zn at a molar ratio from 0.2 to about 3 relative to iron.

The reduction catalyst may comprise K, Na, Cs, Rh, Rb, Mn, Li, Pt, Pd, Ru, Cu, Mo, Ce, or a combination thereof at a molar ratio of about 0.01 to about 0.20, about 0.01 to about 0.10, about 0.01 to about 0.08, about 0.01 to about 0.05, or about 0.02 to about 0.4 relative to iron. In other embodiments, the reduction catalyst comprises Na or K at a molar ratio of about 0.01 to about 0.20, about 0.01 to about 0.10, about 0.01 to about 0.08, about 0.01 to about 0.05, or about 0.02 to about 0.4 relative to iron.

The reduction catalyst may comprise K, Na, Cs, Rh, Rb, Mn, Li, Pt, Pd, Ru, Cu, Mo, Ce, or a combination thereof in an amount of about 0.1 wt % to about 10 wt %, about 0.2% to about 10%, about 0.1% to about 2%, about 0.5% to about 5%, about 0.2% to about 1.5%, or about 0.5% to about 1.0% of the total weight of iron plus zinc. In certain embodiments, the reduction catalyst comprises Na or K in an amount of about 0.2% to about 10%, about 0.5% to about 5%, about 0.5% to about 3%, about 0.5% to about 1%, or about 1% to about 5% of the total weight of iron plus zinc. In other embodiments the reduction catalyst may comprise Na in an amount of about 0.2% to about 10%, about 0.5% to about 5%, about 0.5% to about 3%, about 0.5% to about 1%, or about 1% to about 5% of the total weight of iron plus zinc.

The reduction catalyst may comprise iron, zinc and one or more Group IA or IIA metals, having a molar ratio of iron to zinc of about 1:1 to about 4.5:1, about 1.5:1 to about 3.5:1, about 1.5:1 to about 3:1, or about 1.5:1 to about 2.5:1; and the one or more Group IA or IIA metals present at about 0.5% to about 1.0% of the total weight of iron plus zinc.

The reduction catalyst may comprise iron, zinc, and the one or more Group IA, IIA or X metals being sodium, lithium, platinum, cesium, rubidium, manganese, or potassium, having a molar ratio of iron to zinc of about 1.5:1 to about 2.5:1; and the Na, Li, Rb, Mn, Cs, Pt, or K present at about 0.5% to about 1.0% of the total weight of iron plus zinc. The reduction catalyst may comprise iron, zinc, and the one or more Group IA or IIA metals being sodium or potassium, having a molar ratio of iron to zinc of about 1.5:1 to about 2.5:1; and the Na or K present at about 0.5% to about 1.0% of the total weight of iron plus zinc.

In certain aspects, the reduction catalysts further comprise a reduction catalyst support. The reduction catalyst support may be any suitable material that can serve as a catalyst support.

In some embodiments, the catalyst support comprises one or more materials selected from an oxide, nitride, fluoride, silicate, or carbide of an element selected from aluminum, silicon, titanium, zirconium, cerium, magnesium, yttrium, lanthanum, zinc, and tin. In further embodiments, the catalyst support comprises one or more materials selected from an oxide, nitride, fluoride, silicate, or carbide of an element selected from aluminum, silicon, titanium, zirconium, cerium, magnesium, yttrium, lanthanum, zinc, iron, and tin. In some preferred embodiments, the catalyst support comprises 7-alumina. In certain embodiments, the catalyst support is selected from carbon, silica, zeolite, alumina, zirconium oxide, titanium oxide, and silica carbide. In certain embodiments, the additional support is selected from carbon, silica, zeolite, alumina, iron oxide, zirconium oxide, titanium oxide, and silica carbide. In some embodiments, the catalyst support is an aluminum oxide that is formed in-situ as part of the catalyst. In some embodiments, the catalyst support is selected from, but not limited to, Al₂O₃, ZrO₂, SnO₂, SiO₂, ZnO, and TiO₂. In some embodiments, the catalyst support is selected from Al₂O₃, ZrO₂, SnO₂, SiO₂, ZnO, and TiO₂. In some embodiments, the catalyst support is selected from Al₂O₃, ZrO₂, SnO₂, SiO₂, ZnO, Fe₂O₃, Fe₃O₄, FeO, and TiO₂.

In some embodiments, the reduction catalyst support comprises one or more carbon-based materials. In some embodiments, the carbon-based material is selected from activated carbon, carbon nanotubes, graphene, and graphene oxide.

In some embodiments, the reduction catalyst support is selected from SiAlO_x, SO₄—ZrO₂, zirconium tungstate, tungstated-titania, and anatases (SiO₂—Al₂O₃, SiO₂—TiO₂). In further embodiments, the reduction catalyst support is an aluminum-based material such as alumina (e.g., γ-alumina), boehmite, crystalline boehmite, pseudoboehmite, gibbsites, and thermally shocked gibbsites.

In some embodiments, the reduction catalyst support is a zeolite such as Y-type zeolites, beta-zeolites, ZSM-type zeolites (e.g., ZSM-5, HZSM-5, ZSM-12, ZSM-22, ZSM-57), SAPO type zeolites (e.g., SAPO11, SAPO31, SAPO41), L zeolite (LTL), mordenite zeolites, MCM-49, MCM-22, DA-114, microcrystalline USY zeolite, microcrystalline USY zeolite, and combinations thereof. In certain embodiments, the reduction catalyst support is MCM-49. In further embodiments, the zeolites comprise a modifier such as Zn, Ga, Fe, or other transition metals. In yet further embodiments, the modifier is present as zeolite supported metals or as isomorphous substitution in the zeolite framework.

In some embodiments, the reduction catalyst support is modified with molybdenum, chlorine, and/or sulfur.

In certain embodiments, the reduction catalyst support is a mesoporous material. In such embodiments, as will be appreciated by one of ordinary skill in the art, the physical characteristics of the mesoporous material, e.g., mesopore volume and surface area may be measured using standard gas absorption measurement techniques known in the art including, for example, the Barrett-Joyner-Halenda (BJH) method for determining pore size distributions and pore volumes, and the Brunauer, Emmett and Teller (BET) method for obtaining the specific surface area (hereinafter “surface area”). In further embodiments, the reduction catalyst support has a mesopore volume from about 0.01 to about 3.0 cc/g.

In certain embodiments, the reduction catalyst support has surface area from about 10 m²/g to about 1000 m²/g. In certain embodiments, the reduction catalyst comprising the reduction catalyst support has a surface area from about 10 m²/g to about 1000 m²/g.

In certain embodiments, the reduction catalyst comprises the reduction catalyst support in a form of particles having an average size from about 10 nm to about 5 μm, about 20 nm to about 5 μm, about 50 nm to about 1 μm, about 100 nm to about 500 nm, or about 50 nm to about 300 nm.

In certain embodiments, the reduction catalyst comprises the reduction catalyst support in an amount from about 5 wt. % to about 80 wt. %, about 5 wt. % to about 70 wt. %, about 20 wt. % to about 70 wt. %, or about 30 wt. % to about 70 wt. % of the reduction catalyst.

In certain embodiments, the reduction catalyst support is a high surface area scaffold. In further embodiments, the reduction catalyst support comprises mesoporous silica. In yet further embodiments, the reduction catalyst support comprises carbon allotropes.

In certain embodiments, the reduction catalyst is a nanoparticle catalyst. In further embodiments, the particle sizes of the reduction catalyst on the surface of the scaffold are about 1 nm to about 5 nm, about 5 nm to about 100 nm, or about 100 to about 500 nm. In certain embodiments, the particles not subjected to agglomeration are 100-500 nm in particle size.

In certain embodiments, the reduction catalyst is pretreated with syngas. In yet further embodiments, the reduction catalyst is pretreated with hydrogen. In still further embodiments, the reduction catalyst is heated with inert gas (including but not limited to nitrogen gas, argon) before the production.

The reduction catalyst may include a binder. The binder may be any binder known for use in the art. The binder may be selected from the group consisting of: boehmite (e.g., PURAL® TH 100, PURAL® TH 80, PURAL® TH 200, PURAL® 200), silica-alumina hydrate (e.g., SIRAL® 1, SIRAL® 5, SIRAL® 10, SIRAL® 20, SIRAL® 40), aluminate (e.g., sodium-aluminate), silica (e.g., silicates, such as potassium-silicate and sodium-silicate, LUDOX®) pseudoboehmite alumina (e.g., VERSAL® V-250), bentonite clay, montmorillonite clay, tungsten, zirconate, or any combination thereof.

The binder may be present in an amount of about 0.1% to about 60% by weight, about 5% to about 40%, or about 10% to about 30% by weight of the total catalyst composition. In certain embodiments, the binder is present in about 0.1% to about 30%, about 0.1% to about 20%, about 1% to about 30%, about 1% to about 20%, about 5% to about 25%, about 5% to about 20%, about 10% to about 20%, about 5% to about 15%, or about 15% to about 25% by weight of the total catalyst composition.

The binder may contain a promoter element selected from Na, K, Cs, Li, Rb, or a combination thereof. It was found that a promoter in the binder improves catalyst performance, e.g., activity, selectivity and stability; by maintaining the promoter level constant on the active metal components. In particular, the benefits of doping the binder include:

• • improves methane selectivity;
  • the acidity improves hydrocarbon yield;
  • creates meso-porosity to the formed catalyst which may improve product selectivity; and
  • reduces metal leaching.

The binder may be heterogeneous, amorphous or micro-porous materials. In certain embodiments, the binder may be selected from the group consisting of: sodium-aluminate, potassium-silicate, sodium-silicate, and any combination thereof. The binder may be selected from Na-aluminate, K-aluminate, Na-silicate, K-silicate, Na-zirconate, K-zirconate, Na-tungsten, K-tungsten or a combination thereof.

When a promoter is added to the binder, performance (e.g., in terms of SC₁ and SC₅₊) of the catalyst improves significantly. When comparing performance of a catalyst having a binder without a promoter to the same catalyst and binder with a promoter, SC₁ may improve (that is, decrease) by about 20% to about 65%, about 30% to about 55%, about 30% to about 40%, or about 45% to about 55%. When comparing performance of a catalyst having a binder without a promoter to the same catalyst and binder with a promoter, SC₅₊ may improve (that is, increase) by about 25% to about 75%, 30% to about 50%, about 50% to about 75%, or about 55% to about 65%. For example, the foregoing comparisons may be between a non-doped silicate binder and a doped (with promoter) silicate binder, or between a non-doped alumina binder and a doped (with promoter) silicate binder.

A binder may be preferably selected that minimizes or does not form any strong metal support interactions with the active metal(s) because forming such interactions would inhibit the catalytic properties of the active metal. A preferred binder may bond the small active metal particles together and form a sizeable extrudate/pellets (1-5 mm). These extrudates/pellets are suited for application in industrial reactors. They also have better handling properties and avoid pressure drops in large scale reactors.

The binder disclosed herein reduces metal leaching which improves the catalyst life span. With a powder, the surface area is very large and so by forming an extrudate with a binder, thermal shock in large scale reactors may be reduced.

In certain embodiments, when the reduction catalyst comprises iron oxide and zinc oxide, and a Group IA or IIA metal, and when the first carbon source gas and first reduction gas are fed into the reduction reactor, the iron oxide reacts to be in an active form selected from the group consisting of: Fe_xO_y, Fe_xC_y, and any combination thereof, where x is 1-3 and y is 0-4. The active form acts to convert CO₂ to hydrocarbons selected from the group consisting of: olefins, paraffins, oxygenates, and any combination thereof.

Catalysts for Conversion of Carbon Sources and Reduction Gas to Aromatics

In certain aspects, the systems and methods of the present disclosure involve the use of aromatic catalysts. As used herein, the term “aromatic catalyst” refers to a catalyst used for the conversion of carbon sources and reduction gases to aromatics, but which does not necessarily itself comprise aromatics. Use of an aromatic catalyst may also produce other hydrocarbons in a lesser amount.

In certain embodiments, the aromatic catalyst comprises a zeolite. In certain embodiments, the zeolite is selected from Y-type zeolites, beta-zeolites, ZSM-type zeolites (e.g., ZSM-5, HZSM-5, ZSM-12, ZSM-22, ZSM-57), SAPO type zeolites (e.g., SAPO11, SAPO31, SAPO41), L zeolite (LTL), mordenite zeolites, a zeolite of the MWW structural type, such as MCM-22, MCM-36, MCM-49, and MCM-56, DA-114, microcrystalline USY zeolite, microcrystalline USY zeolite, and combinations thereof. In certain embodiments, the zeolite is ZSM-5, MCM-49, or MCM-22. The zeolite may be ZSM-5. The ZSM-5 may have a silicon to aluminum ratio (SAR) of about 30 to about 1000, about 30 to about 400, about 80 to about 400, about 80 to about 280, or about 30 to about 280.

The zeolite may comprise a modifier. The modifier may be Ga, Fe, Mn, Zn, P, Pt, or a combination thereof. In certain embodiments, the zeolite comprises from 0 wt % to about 10 wt % of the modifier. In further embodiments, the zeolite comprises from 0.01 wt % to about 10 wt % of the modifier, from 0.01 wt % to about 5 wt % of the modifier, from 0.01 wt % to about 3 wt % of the modifier, from 0.1 wt % to about 1.5 wt % of the modifier, or from 0.5 wt % to about 1 wt % of the modifier. In certain embodiments, the zeolite is ZSM-5 modified with Ga, Fe, Mn, P, Pt, or Zn. The zeolite may be ZSM-5 modified with Zn, optionally in an amount of 0 wt % to about 10 wt % of the total catalyst composition.

Optional features of the invention relating to catalysts for conversion of carbon sources and reduction gas to aromatics described above may also constitute optional features in relation to catalysts for conversion of carbon sources to paraffins or catalysts for conversion of carbon source gases and reduction gases to linear alpha olefins, and vice versa.

The aromatic catalyst may include a binder. The binder may be any binder known for use in the art. In certain embodiments, the binder may be selected from the group consisting of: boehmite (e.g., PURAL® TH 100, PURAL® TH 80, PURAL® TH 200, PURAL® 200), silica-alumina hydrate (e.g., SIRAL® 1, SIRAL® 5, SIRAL® 10, SIRAL® 20, SIRAL® 40), aluminate, silicon, zirconium, silica, pseudoboehmite alumina (e.g., VERSAL® V-250), bentonite, or any combination thereof. The binder may be present in an amount of about 0% to about 60% by weight, or about 0% to about 40% by weight of the total catalyst composition. In certain embodiments, the binder is present in about 0.1% to about 30%, about 0.1% to about 20%, about 1% to about 30%, about 1% to about 20%, about 1% to about 15%, about 5% to about 30%, about 5% to about 20%, about 5% to about 15%, about 0.5% to about 10%, about 0.5% to about 5% by weight of the total catalyst composition. In an embodiment, the aromatic catalyst includes a silica binder in amount of about 15% to about 25%, or about 20% by weight of the total catalyst composition.

In certain embodiments, aromatic catalysts of the disclosure are active in the conversion of a carbon source gas, such as CO₂, to aromatics. In other embodiments, aromatic catalysts of the disclosure are active in the conversion of a carbon source gas, such as CO₂, and an olefin source to aromatics. The olefin source may be a hydrocarbon product mixture, such as a medium hydrocarbon product mixture comprising one or more C_5-8 paraffins and/or olefins, or an olefin product mixture, such as a stream comprising one or more C_5-8 olefins, to aromatics.

The feed stream through the aromatic catalyst may carbon source gas be a mixture of hydrocarbons, including, but not limited to, olefins. Accordingly, the selectivity for the aromatic catalyst refers to conversion of hydrocarbons, including, but not limited to, olefins, to the specified aromatic molecule(s). Optionally, the selectivity for the aromatic catalyst refers to conversion of hydrocarbons, including, but not limited to, olefins, in the presence of a carbon gas source to the specified aromatic molecule(s). The aromatic catalyst used herein may have a selectivity for aromatics of over about 50 carbon mole %, over about 55 carbon mole %, over about 60 carbon mole %, or over about 65 carbon mole %. The aromatic catalyst may have a selectivity for aromatics of about 50 carbon mole % to about 90 carbon mole %, about 55 carbon mole % to about 85 carbon mole %, about 60% to about 85 carbon mole %, or about 65 carbon mole % to about 80 carbon mole %. The aromatic catalyst used herein may have a selectivity for target aromatic of about 5 carbon mole % to about 20 carbon mole %, or about 7 carbon mole % to about 15 carbon mole %. The aromatic catalyst used herein may have a selectivity for methane of less than about 8 carbon mole %, less than about 5 carbon mole %, or less than about 4 carbon mole %. The aromatic catalyst used herein may have a selectivity for methane of about 1 carbon mole % to about 8 carbon mole %, about 2 carbon mole % to about 6 carbon mole %, about 2 carbon mole % to about 5 carbon mole %, or about 3 carbon mole % to about 4 carbon mole % by weight.

Catalysts for Alkylation of Aromatics

The alkylation step may be performed with any suitable catalyst. In certain embodiments, the alkylation catalyst is a liquid acid, such as HF, SPA (solid phosphoric acid), a Friedel-Crafts alkylation catalyst (e.g., HF/AlCl₃), tungsten, platinum, or a zeolite. In further embodiments, the alkylation catalyst is a zeolite, such as an acidic zeolite. In yet further embodiments, the zeolite is selected from Y-type zeolites, beta-zeolites, ZSM-type zeolites (e.g., ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-57), SAPO type zeolites (e.g., SAPO-11, SAPO-5, SAPO-31, SAPO-41), L zeolite (LTL), mordenite zeolite, a zeolite of the MWW structural type, such as MCM-22, MCM-36, MCM-49, PSH-3, and MCM-56, DA-114, USY zeolite, and combinations thereof. In certain embodiments, the zeolite is MCM-22, MCM-49, PSH-3, mordenite zeolite, Y-type zeolite, or beta-zeolite.

The weight-based space velocity is measured as the amount of reactant mass per unit catalyst mass per unit time. The range for the weight-based space velocity for the alkylation catalyst is between about 0.1 g of reactant per g of catalyst per hour (0.1 h−1) and about 50 h−1, or between about 0.5 h−1 to about 20 h⁻¹.

The systems and methods of the present disclosure may include a reforming catalyst to produce aromatics. As used herein, the term “reforming catalyst” refers to a catalyst used for the conversion of carbon sources to aromatics, such as benzene, toluene and xylenes (together referred to as “BTX”), and heavy aromatics, but which does not necessarily itself comprise aromatics. Use of a reforming catalyst may also produce other hydrocarbons in a lesser amount.

Reforming catalysts may convert naphthenes to aromatics. Naphtha feeds contain both five-membered and six-membered naphthene rings (cyclopentane, alkyl-cyclopentanes, cyclohexane, and alkyl-cyclohexanes). The six-carbon ring cyclohexanes, for example, can be directly dehydrogenated to produce aromatics and hydrogen on metallic sites. This is a very fast reaction that produces significant endotherms in the lead reactors due to the large amount of six-carbon ring naphthenes typically in the naphtha feed. Under reforming conditions, this reaction greatly favors aromatics thermodynamically. To convert five-membered ring alkyl cyclopentanes to an aromatic, they are first hydroisomerized to give a cyclohexane intermediate prior to dehydrogenation to aromatics. The conversion of an alkylcyclopentane ring to an aromatic requires both reactions to occur in series and therefore requires both the acid and the metal function of the reforming catalyst. Paraffins are dehydrogenated on the platinum sites to form olefins that can then isomerize over the acid function of the catalyst to provide higher octane branched paraffins. Within a given carbon number, the concentrations of normal paraffins, branched paraffins, and their corresponding olefins tend to be at or near equilibrium at the reactor outlet. Although olefins are normally at relatively low levels in the reformate product, they also contribute positively to the octane compared with paraffins. Another function of the reforming catalyst is for paraffins to cyclize to cyclohexanes and cyclopentanes (dehydrocyclization).

The reforming catalyst may include both metal sites for dehydrogenation reactions and acid sites for isomerization and cyclization reactions. Reforming catalysts may comprise platinum supported on an alumina support, optionally modified, for example, a chlorinated alumina support. The reforming catalyst may also include an additional metal component to modify either the acidic or metallic sites. The reforming catalyst may be modified and used with a fixed bed and be semi-regenerative or cyclic or continuously regenerating reforming. The support used for reforming catalysts may be a high surface area gamma (Y) alumina of the formula Al₂O₃·nH₂O with a porous structure forming a complex network of interconnected channels. Reforming catalysts are explained in detail in Egolf, B., et al., “The Honeywell UOP CCR Platforming™ Process for BTX Production (Case Study),” Industrial Arene Chemistry, Chapter 10, 2023, pp. 269-294 is incorporated by reference herein in its entirety.

The reforming catalyst may comprise a molecular sieve. The reforming catalyst may comprise a zeolite. The reforming catalyst may comprise any such catalysts known for this use in the art, for example those developed and sold by UOP, including but not limited to UOP R-560, UOP R-364, and any combination thereof.

The reforming catalyst may comprise platinum (Pt), palladium (Pd), or a combination thereof. The reforming catalyst may comprise platinum, and an optionally modified support. The reforming catalyst may comprise platinum, an optionally modified alumina support, and an additional metal component. The reforming catalyst may comprise platinum, a chlorinated alumina support, and an additional metal component. The reforming catalyst may comprise a bimetallic formulation of Pt with Iridium or Rhenium supported on alumina (Al₂O₃).

In certain embodiments, reforming catalysts of the disclosure, such as those described above, are active in the conversion of a carbon source gas, such as CO₂ or naphtha, to aromatics, such at BTX.

Catalysts for Oligomerization

The oligomerization catalyst may be a heterogeneous acid catalyst, such as a zeolite or a molecular sieve. The oligomerization catalyst may be an amorphous or crystalline aluminosilicate molecular sieve. The oligomerization catalyst may be a zeolite. The oligomerization catalyst may be an aluminosilicate zeolite. The oligomerization catalyst may be selected from ZSM-5, ZSM-11, ZSM-22, Theta-1, ZSM-23, ZSM-12, ZSM-57, ZSM-35, beta-zeolite, a faujasite, a mordenite, SAPO-5, SAPO-11, a zeolite of the MWW structural type, such as MCM-22, MCM-36, MCM-49, PSH-3, and MCM-56, and any combination thereof. The oligomerization catalyst may be ZSM-5, beta-zeolite, MCM-22, MCM-49, PSH-3, mordenite, SAPO-5, or a combination thereof. The oligomerization catalyst may be selected from ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-35, and any combination thereof. The oligomerization catalyst may be ZSM-5.

The weight-based space velocity is measured as the amount of reactant mass per unit catalyst mass per unit time. The range for the weight-based space velocity for the oligomerization catalyst is between about 0.1 g of reactant per g of catalyst per hour (0.1 h−1) and about 50 h−1, or between about 0.5 h−1 to about 20 h⁻¹.

When the oligo-alkylation reactor is used, a combination of one or more alkylation catalyst and one or more oligomerization catalysts may be combined within the oligo-alkylation reactor. The one or more alkylation catalyst and the one or more oligomerization catalysts may be mixed, layered within the reactor optionally with an intermediate quench. In other embodiments, an oligo-alkylation catalyst may be used. The oligo-alkylation catalyst may be a liquid acid, such as HF, SPA (solid phosphoric acid), a Friedel-Crafts alkylation catalyst (e.g., HF/AlCl₃), an amorphous heterogeneous acid catalyst, such as tungsten/Zr oxide, a heterogeneous acid catalyst, such as a zeolite or a molecular sieve, and a combination thereof. In some embodiments, the oligo-alkylation catalyst is an amorphous or crystalline aluminosilicate molecular sieve. In other embodiments, the oligo-alkylation catalyst is selected from the group consisting of: ZSM-5, ZSM-11, ZSM-22, Theta-1, ZSM-23, ZSM-12, ZSM-57, ZSM-35, zeolite beta, a faujasite, a mordenite, SAPO-5, SAPO-11, a zeolite of the MWW structural type, such as MCM-22, MCM-36, MCM-49, and MCM-56, and any combination thereof. In further embodiments, the oligo-alkylation catalyst is ZSM-5, beta-zeolite, MCM-22, MCM-49, mordenite zeolite, SAPO-5, or any combination thereof.

Catalysts for Hydrogenation

In certain aspects, the systems and methods of the present disclosure involve the use of a hydrogenation catalyst (referred to herein as “hydrogenation catalysts”) for hydrogenating percentages of the hydrocarbons produced. Any suitable hydrogenation catalyst known in the art may be used in these processes. However, the particular embodiments set forth below are provided both to exemplify the use of such catalysts and to identify catalysts particularly well-suited for use in conjunction with the other features of the systems and methods disclosed herein.

In certain embodiments, the hydrogenation catalysts of the present disclosure are aluminosilicate catalysts, such as zeolites. In further embodiments, the hydrogenation catalyst is AlCl3. In yet further embodiments, the hydrogenation catalyst is doped with a transition metal, such as Pt, Pd, etc. In still further embodiments, the hydrogenation catalyst is Pt on beta-zeolite. In certain embodiments, hydrogenation catalysts of the disclosure comprise an hydrogenation metal, and an hydrogenation support. The hydrogenation support may be any suitable material that can serve as a catalyst support.

In some embodiments, the hydrogenation support comprises one or more materials selected from an oxide, nitride, fluoride, silicate, or carbide of an element selected from aluminum, silicon, titanium, zirconium, cerium, magnesium, yttrium, lanthanum, zinc, tungsten, and tin. In some preferred embodiments, the hydrogenation support comprises γ-alumina. In certain embodiments, the hydrogenation support is selected from carbon, silica, zeolite, alumina, zirconium oxide, titanium oxide, and silica carbide. In some embodiments, the hydrogenation support is selected from alumina (e.g., γ-alumina), boehmite, crystalline boehmite, pseudoboehmite, gibbsites, and thermally shocked gibbsites. In some embodiments, the hydrogenation support is an aluminum oxide that is formed in-situ as part of the paraffin catalyst. In some embodiments, the hydrogenation support is selected from, but not limited to, MgO, Al2O3, ZrO2, SnO2, SiO2, ZnO, WO3, and TiO2. In some embodiments, the hydrogenation support is selected from MgO, Al2O3, ZrO2, SnO2, SiO2, ZnO, WO3, silica carbide, and TiO2.

In some embodiments, the hydrogenation support comprises one or more carbon-based materials. In some embodiments, the carbon-based material is selected from activated carbon, carbon nanotubes, graphene, and graphene oxide.

In some embodiments, the hydrogenation support is selected from SiAlOx, SO4-ZrO2, zirconium tungstate, tungstated-titania, and anatases (SiO2—Al2O3, SiO2-TiO2). In further embodiments, the hydrogenation support is an aluminum-based material such as alumina (e.g., γ-alumina), boehmite, crystalline boehmite, pseudoboehmite, gibbsites, and thermally shocked gibbsites.

In some embodiments, the hydrogenation support is a zeolite such as Y-type zeolites, beta-zeolites, ZSM-type zeolites (e.g., ZSM-5, HZSM-5, ZSM-12, ZSM-22, ZSM-57), SAPO type zeolites (e.g., SAPO11, SAPO31, SAPO41), mordenite zeolites, MCM-49, MCM-22, DA-114, microcrystalline USY zeolite, microcrystalline USY zeolite, and combinations thereof. In further embodiments, the zeolites comprise a modifier such as Zn, Ga, Fe, or other transition metals. In yet further embodiments, the modifier is present as a zeolite supported metal or as isomorphous substitution in the zeolite framework.

In some embodiments, the hydrogenation support is modified with molybdenum, chlorine, and/or sulfur.

In further embodiments, the hydrogenation metal is selected from Pd, Pt, Ni—Co, Ni—W, and Ni—Mo. In yet further embodiments, the zeolite support is selected from SiAlO_x, SO₄—ZrO₂, Y-type zeolites, beta-zeolite, ZSM5, ZSM22, SAPO11, SAPO31, SAPO41, MCM-49, MCM-22, TiO2, WO3, zirconium tungstate, tungstated-titania, and anatases (SiO2—Al2O3, SiO2-TiO2). In some embodiments, the zeolite support is selected from TiO2, WO3, zirconium tungstate, tungstated-titania, and anatases (SiO2—Al2O3, SiO2-TiO2). In still further embodiments, the hydrogenation catalyst is selected from Pt/ZrO2/WO3, Pt/ZrWO4, Pt/SiAlOx, Pt/SO4-ZrO2, Pt/ZSM5, Pt/ZSM22, PU/SAPO, Ni—W/SiAlOx, Ni—W/SO4-ZrO2, Ni—W/ZSM5, Ni—W/ZSM22, and Ni—W/SAPO. In certain embodiments, the hydrogenation catalyst is Pt on a zeolite support. In certain embodiments, the hydrogenation catalyst is Pt/ZrO2/WO3. In other preferred embodiments, the hydrogenation catalyst is Pt/SAPO comprising 0.2 wt % Pt.

In certain embodiments, the hydrogenation metal comprises from about 0.5 wt % to about 40 wt % of the hydrogenation catalyst. In further embodiments, the hydrogenation metal comprises about 0.5 wt % of the hydrogenation catalyst. In yet further embodiments, the hydrogenation metal comprises about 1 wt % of the hydrogenation catalyst. In still further embodiments, the hydrogenation metal comprises about 10 wt % of the hydrogenation catalyst. In certain embodiments, the hydrogenation metal comprises about 20 wt % of the hydrogenation catalyst. In further embodiments, the hydrogenation metal comprises about 30 wt % of the hydrogenation catalyst. In yet further embodiments, the hydrogenation metal comprises about 40 wt % of the hydrogenation catalyst.

Optional and preferred features of the invention relating to catalysts for hydrogenation described above may also constitute optional or preferred features in relation to catalysts for conversion of carbon sources to paraffins, catalysts for conversion of carbon source gases and reduction gases to linear alpha olefins or catalysts for conversion of carbon sources and reduction gas to aromatics, and vice versa.

Reduction Gases, Carbon Source Gases, and Ratios Thereof

The systems and methods of the present disclosure can be designed to utilize any combination of suitable reduction gases and suitable carbon source gases. Said carbon source and reduction gases may in certain embodiments be provided into the requisite reaction vessels separately, or they may in certain embodiments be pre-mixed (e.g., the first reduction gas feed and the first carbon source gas feed can, in some embodiments refer to the same physical feature, as can the second reduction as feed and the second carbon source gas feed) to provide a single feed stream comprising both a carbon source gas and a reduction gas, which is coupled to the appropriate reactor.

Additionally, a single gas feed comprising the first reduction gas feed, the first carbon source gas feed, the second reduction gas feed, and the second carbon source gas feed can be pre-mixed to provide a single feed stream comprising both a carbon source gas and a reduction gas, coupled to both the aromatic reactor and the paraffin reactor.

In certain embodiments, the single gas feed may include CO₂, H₂, CO, C₂, C₃, CH₄, and any combination thereof. The feed stream may contain H₂/CO₂, in a range of about 10% to about 95%, and each of CO, C₂, C₃, and CH₄ in the range of about 0% to about 65%. The source of CO, C₂, C₃, and/or CH₄ may be from a recycle stream or may be introduced in the fresh feed stream.

The first reduction gas and/or second reductions gas may be selected from H₂, a hydrocarbon, synthesis gas (CO/H₂), or from a gas that is, or is derived from, flare gas, waste gas, or natural gas. In certain embodiments, the first reduction gas and/or second reductions gas is H₂. In further embodiments, the first reduction gas and/or second reductions gas is synthesis gas. In yet further embodiments, the first reduction gas and/or second reductions gas is a hydrocarbon, such as CH₄, ethane, propane, or butane. In still further embodiments, the first reduction gas and/or second reductions gas is derived from, flare gas, waste gas, or natural gas. In certain embodiments, the first reduction gas and/or second reductions gas is CH₄.

In certain embodiments, the first carbon source gas and/or second carbon gas comprises CO₂. In further embodiments, the first carbon source gas and/or second carbon gas is CO₂. In yet further embodiments, the first carbon source gas and/or second carbon gas comprises CO.

As will be understood by those of skill in the art, the flow rate of carbon source gas and/or reduction gas, or various product mixtures through the paraffin and/or aromatic reactors (or elsewhere in the disclosed systems and methods) can be adjusted as needed to afford the desired product output characteristics.

Additionally, as will be understood by those of skill in the art, the carbon source gases and the reduction gases may be provided in any suitable ratio that affords the desired product output characteristics. In certain embodiments, the molar ratio of the first reduction gas to the first carbon source gas is from about 10:1 to about 1:10. In further embodiments, the molar ratio of the first reduction gas to the first carbon source gas is from about 5:1 to about 0.5:1, or about 1:1 to about 5:1. In yet further embodiments, the molar ratio of the second reduction gas to the second carbon source gas is from about 10:1 to about 1:10. In still further embodiments, the molar ratio of the second reduction gas to the second carbon source gas is from about 5:1 to about 0.5:1.

Definitions

Unless otherwise defined herein, scientific and technical terms used in this application shall have the meanings that are commonly understood by those of ordinary skill in the art. Generally, nomenclature used in connection with, and techniques of, chemistry, cell and tissue culture, molecular biology, cell and cancer biology, neurobiology, neurochemistry, virology, immunology, microbiology, pharmacology, genetics and protein and nucleic acid chemistry, described herein, are those well known and commonly used in the art.

The methods and techniques of the present disclosure are generally performed, unless otherwise indicated, according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout this specification. See, e.g. “Principles of Neural Science”, McGraw-Hill Medical, New York, N.Y. (2000); Motulsky, “Intuitive Biostatistics”, Oxford University Press, Inc. (1995); Lodish et al., “Molecular Cell Biology, 4th ed.”, W. H. Freeman & Co., New York (2000); Griffiths et al., “Introduction to Genetic Analysis, 7th ed.”, W. H. Freeman & Co., N.Y. (1999); and Gilbert et al., “Developmental Biology, 6th ed.”, Sinauer Associates, Inc., Sunderland, MA (2000).

Chemistry terms used herein, unless otherwise defined herein, are used according to conventional usage in the art, as exemplified by “The McGraw-Hill Dictionary of Chemical Terms”, Parker S., Ed., McGraw-Hill, San Francisco, C.A. (1985).

All of the above, and any other publications, patents and published patent applications referred to in this application are specifically incorporated by reference herein. In case of conflict, the present specification, including its specific definitions, will control.

The term “Log of solubility”, “Log S” or “log S” as used herein is used in the art to quantify the aqueous solubility of a compound. The aqueous solubility of a compound significantly affects its absorption and distribution characteristics. A low solubility often goes along with a poor absorption. Log S value is a unit stripped logarithm (base 10) of the solubility measured in mol/liter.

The term “monocyclic aromatic(s)” as used herein refer to compounds comprising only one single aromatic ring, which may be substituted or unsubstituted (e.g., alkylbenzenes), and which may optionally be fused with non-aromatic rings (e.g., tetralins and indanes).

The term “polycyclic aromatic(s)” as used herein refers to compounds comprising at least two aromatic rings, which may be fused (e.g., two distinct rings sharing two adjacent ring atoms). As a non-limiting example, the term “polycyclic aromatics” may be used to refer to a group of compounds comprising naphthalene and/or naphthalene derivatives.

The term “petroleum-derived” as used herein refers to compounds and compositions that are derived by physical and chemical processes from petroleum feedstocks, but does not include compounds and compositions whose carbon is derived from carbon dioxide or carbon monoxide, even if that carbon dioxide or carbon monoxide was produced from petroleum feedstocks (e.g., by combusting petroleum).

When the amount of an impurity is specified at a level of “about 0”, it is understood by those of skill in the art that such a measurement is accurate to a certain number of significant figures based on the relevant detection method used.

As used herein, certain components, fractions, and feeds are described in terms of the carbon numbers (e.g., C_X-Y) in said component, fraction, feed, etc. These descriptions indicate the possible (non-limiting) carbon numbers of the hydrocarbons present in said component, but do not require the presence of each and every carbon number within the range. For example, a feed described as comprising C_9-15 hydrocarbons must comprise at least one component falling within the range of carbon numbers listed.

As used herein, the term “selectivity” and grammatical variants thereof refer to how selective a particular process or catalyst is for producing a particular product. The term refers to an exemplary selectivity value observed for a reaction performed with suitable reagents under conditions that have been selected, by a person of ordinary skill in the art, to maximize or minimize the production of a given product of interest. A value for selectivity may refer to the proportion of product(s) of interest compared to other products produced (which may not be of interest), or may refer to the proportion of other product(s) produced compared to product(s) of interest. Selectivity may be a function of the catalyst used in a process, and/or may be a function of process design or parameters (e.g., temperature, pressure, reagent concentration, GHSV, etc.), as would be understood by a person of ordinary skill in the art. Those of skill in the art are familiar with how to calculate selectivity for a given product. However, where an explicit calculation for selectivity is provided herein, that calculation method controls.

As used herein, the term “oligomerization,” and grammatical variants thereof, will be understood by those of skill in the art to refer to a process that may involve dimerization, trimerization, tetramerization, pentamerization, hexamerization, heptamerization, octamerization, nonamerization, decamerization, higher-order oligomerization, and combinations thereof. The extent of oligomerization in a particular reaction will determine the composition of the product stream, and depends on aspects of the reactant stream, as well as the reaction conditions.

EXAMPLES

The invention now being generally described, it will be more readily understood by reference to the following examples which are included merely for purposes of illustration of certain aspects and embodiments of the present invention, and are not intended to limit the invention.

Example 1

In this pathway, aliphatic hydrocarbons are derived from both CO₂ hydrogenation which converts carbon dioxide to a mixture of hydrocarbons including olefins and paraffins, followed by oligomerization, while aromatics and cycloparaffins are produced via alkylation. This process utilizes the light carbon fractions in alkylation step that are not used in other pathways, such as that in FIG. 3.

(1) CO₂ Hydrogenation (Reduction) and Separation

A feed mixture of CO₂ and hydrogen was fed into a reduction reactor loaded with metal oxide catalysts, operating optionally in recycle mode. In recycle mode, the process effluent undergoes separations involving pressure swing adsorptions, and naphtha wash to separate the H₂, CO₂ and CO, CH₄ from the rest of the hydrocarbon stream. The unreacted H₂ and CO₂ alone with CO and CH₄ are feed back into the reduction reactor. Certain venting is needed to control the level of CH₄ build up in the recycle loop. The hydrogen-to-CO₂ molar ratio in the feed was 3:1, with a GHSV of 4,000 h 1 and a temperature of 300° C. The reactor effluent contained: 60-80 wt % unreacted CO₂ and hydrogen: 2-10 wt % CO: 15-30 wt % aliphatic hydrocarbons (C₁-C₂₅, >80% linear, paraffinic and olefinic): <2 wt % aromatics and cyclic hydrocarbons; and 2-5 wt % oxygenates. The stream was separated into three fractions: (i) C₉₊ fraction (boiling point >150° C.) that was sent to a hydrogenation reactor; (ii) a portion of the C₃-C₅ hydrocarbons was separated and directed to the aromatization reactor; (iii) the remainder of the C₃-C₅ hydrocarbons and C₅-C₉ fraction are combined and sent to the oxygenate removal reactor (details below).

(2) Aromatization (Aromatic Reactor)

A stream of a portion of the C₃-C₅ hydrocarbons was processed in an aromatic reactor loaded with Zn-modified ZSM-5 catalyst, at operating conditions: WHSV: 8 h⁻¹, Temperature: 550° C., Pressure: <150 psig, The resulting effluent included: gaseous products (C₃-C₅ paraffins and minor olefins); and liquid products. The liquid products included: 50-70 wt % benzene, toluene, and xylenes (BTX); 30-40 wt % C₉₊ aromatics, and <10 wt % paraffinic and olefinic hydrocarbons. The aromatics reactor needed regeneration using diluted air or air at 550° C. to remove the coke once the olefin conversion rate drops.

(3) Oxygenate Removal

The remaining C₃-C₅ and C₅-C₉ fractions were combined, forming a feed with: >95 wt % hydrocarbons (≥60% olefinic, remainder paraffinic), and <5 wt % oxygenates. This feed was processed in a reactor loaded with SAPO-11 zeolite catalyst, at operating conditions: WHSV: 3 h⁻¹, Temperature: 350° C., Pressure: 200 psig, The resulting effluent contained: hydrocarbons (C₁-C₁₈) (>70 wt % olefinic, <30 wt % paraffinic), <5 wt % aromatics and cycloparaffins, and <1 wt % oxygenates. The effluent was separated into: C₃-C₅ fraction sent to the alkylation reactor; and C₃-C₉ fraction directed to an oligomerization reactor.

The oxygenate removal reactor needed regeneration using diluted air or air at 600° C. to remove the coke once the oxygenate removal rate drops.

(4) Alkylation

The alkylation reactor receives feed from both the aromatization reactor and the oxygenate removal reactor.

The alkylation reactor was loaded with a MCM-22 catalyst and operated at operating conditions: WHSV: 5 h−1, Pressure: 400 psig, Temperature: 200° C. The feed of the alkylation was also combined with 80 wt % diluent of hydrocarbon to control the process heat. The effluent from the alkylation reactor contained (diluent is emitted): alkyl aromatics, and cyclo-aromatics; and <5 wt % olefinic hydrocarbons. The effluent was distilled to remove the diluent and unreacted light aromatics. After distillation, the product had a boiling range of 150-350° C. and a carbon number range of C₉-C₂₅.

(5) Oligomerization

A part of the C₃-C₉ stream from the oxygenate removal reactor was fed into an oligomerization reactor loaded with MCM-22 catalyst, 80 wt % of diluent hydrocarbon was added to control the process heat, at operating conditions: WHSV of 3 h−1, Temperature 200° C. The effluent contained (diluent is emitted): >85 wt % iso-olefins, with <15 wt % alpha-olefins, <5 wt % paraffins, and <1 wt % oxygenate. The effluent was distilled to remove the diluent and unreacted light olefins. After distillation, the product had a boiling range of 150-350° C. with a carbon number range of C₉-C₂₅.

(6) Selective Hydrogenation (HYD 1)

The effluent from the alkylation reactor was split and one portion was sent to selective hydrogenation (HYD 1) in a hydrogenation reactor loaded with nickel, based catalyst. The feed was diluted with 60% of the hydrocarbon to control the process heat. The process was operated at a WHSV of 4, temperature of 150° C. with a pressure of 300 psig, the hydrogen to olefin mole ratio is at 1.5:1. In this HYD 1, only olefins were hydrogenated, preserving most aromatics. The resulting stream contained (diluent is emitted): aromatics: >85 wt %, cycloparaffins: <10 wt %, and aliphatic paraffins: <5 wt %, and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅.

(7) Full Hydrogenation (HYD 2)

The remaining portion of the effluent from the alkylation reactor was combined with the effluent from the oligomerization reactor and the C₉₊ fraction from the reduction reactor and sent to full hydrogenation (HYD 2) in a second hydrogenation reactor loaded with nickel based catalyst, where all unsaturation are hydrogenated. The feed was combined with 40% of the saturated hydrotreating product to control the process heat. The process was operated at a WHSV of 3, temperature of 200° C. with a pressure of 450 psig, the hydrogen to olefin mole ratio is at 3:1. The resulting stream contained (diluent is emitted): n-Paraffins and iso-paraffins: >60 wt %, Cycloparaffins: <40 wt %, and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅.

(8) Final Blending

The product streams from HYD 1 and HYD 2 were blended to provide a fully formulated diesel fuel containing: 12 wt % aromatic and 24 wt % cycloparaffins, 34 wt % of iso-paraffins and 30 wt % of n-paraffins, and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅.

Example 2

A diesel fuel composition was prepared according to a scheme for making paraffins from CO₂ (CTP) and aromatics from CO₂ (CTA), which are further processed and blended to make fully formulated diesel fuel. That scheme is provided in FIG. 3.

The paraffins produced were distilled to remove wax. The cuts taken were Cut 1 (Ambient to 65° C.), Cut 2 (65 to 125° C.), Cut 3 (125 to 140° C.), and Cut 4 (140 to 300° C.). Cut 3 and 4 were then treated over Pd/C and Pt on alumina catalyst to remove oxygenates and saturate olefins. This process stream was then distilled again to obtain the 140-292° C. fraction and was then taken for blending. The aromatic stream was produced by propylene oligomerization and distilled to obtain the 150-220 fraction. Some of the aromatics were separated and hydrotreated to produce cycloparaffins. A polishing step was used to remove the fraction less than 170° C. Each of components were blended in a ratio of 50:40:10 volume % (paraffin to cycloparaffin to aromatic). The final sample was used for property testing that is in the table below. Further base wash was performed to remove acids resulting in 0.02 acid number measured in mg of KOH/g.

The properties of the diesel sample are shown in Table 2 and 3.

TABLE 2
	Post processing	Distillation	Blend
Component	steps	cut	ratio
Paraffin	Distill, HDO, distill	140-297	50 vol %
	filtering through clay
	and silica gel
Cycloparaffin	Aromatic distillation,	170+	40 vol %
	hydrogenation
	followed by
	polishing to remove
	the <170 cut.
Aromatic	Distillation	150-230	10 vol %

TABLE 3
Method	Test	Min	Max	Result

ASTM D 4176 - 22

Workmanship

Pass

ASTM D 4052 - 22

API Gravity @ 60° F.

Report Only

46.8

ASTM D 6379 - 21e1

Aromatics (% vol)

35

7

ASTM D 4052 - 22

Density @ 15° C. (kg/L)

Report Only

0.793

ASTM D 93 - 20	Flash Point ° C.	38		44
ASTM D 2709 - 22	Water & Sediment (% vol)		0.05	<0.01
ASTM D 86 - 23ae1	Distillation

	Initial Boiling Point (° C.)	Report Only	153
	10% Recovered (° C.)	Report Only	167
	20% Recovered (° C.)	Report Only	171
	30% Recovered (° C.)	Report Only	176
	40% Recovered (° C.)	Report Only	181
	50% Recovered (° C.)	Report Only	188
	60% Recovered (° C.)	Report Only	196
	70% Recovered (° C.)	Report Only	208
	80% Recovered (° C.)	Report Only	225

90% Recovered (° C.)

288

254

End Point (° C.)

Report Only

284

ASTM D 445 - 24	Viscosity @ 40° C.	1.3	2.4	1.2	Fail
	(mm2/s)
ASTM D 482 - 19	Ash (% mass)		0.01	0.00
ASTM D 2622 - 21	Sulfur (ppm)		15	0
ASTM D 130 - 19	Copper Strip Corrosion		3	1a
	(3 h @ 50° C.)
ASTM D 976 - 21e1	Cetane Index, Calculated	40		42

ASTM D 5773 - 21

Cloud Point (° C.)

Report Only

−33

ASTM D 524 - 15	Carbon Residue 10%		0.15	0.01
(2019)	Bottoms (% mass)
ASTM D 7688 - 18	HFRR Lubricity @ 60° C.,		520	306
	Wear Scar Diameter
	(microns)
ASTM D 664 - 18e2	Acid Number (mg KOH/g)			5.5

Example 3 Paraffinic Diesel Fuel

A paraffinic diesel fuel composition was prepared according to a scheme shown in FIG. 4. In this pathway, the main components in the diesel fuel are aliphatic hydrocarbons from the reduction reactor and oligomerization.

(1) CO₂ Hydrogenation (Reduction) and Separation

A mixture of CO₂ and hydrogen was fed into a reduction reactor loaded with metal oxide catalysts, operating optionally in recycle mode. The hydrogen-to-CO₂ molar ratio is at 3:1, with a GHSV of 4000 h−1 and a temperature of 300° C. The reactor effluent contained: 60-80 wt % unreacted CO₂ and hydrogen; 2-10 wt % CO; 15-30 wt % aliphatic hydrocarbons (C₁-C₂₅, >80% linear, paraffinic and olefinic): <2 wt % aromatics and cyclic hydrocarbons; and 2-5 wt % oxygenates. The reactor effluent was separated into two fractions: (i) C₉₊ fraction (boiling point >150° C.) sent to a hydrogenation reactor; and (ii). C₃-C₉ fraction (>95 wt % hydrocarbons (≥60% olefinic, remainder paraffinic), and <5 wt % oxygenates) sent to the oxygenate removal reactor.

(2) Oxygenate Removal

The oxygenate removal reactor was loaded with SAPO-11 zeolite catalyst, and run at operating conditions: WHSV: 3 h−1, Temperature: 350° C., Pressure: 200 psig. The resulting effluent contained: hydrocarbons (C₁-C₁₈) (>70 wt % olefinic, <30 wt % paraffinic), <5 wt % aromatics and cycloparaffins, and <1 wt % oxygenates. The effluent was then fed to anoligomerization reactor. The oxygenate removal reactor needed regeneration using diluted air or air at 600° C. to remove the coke once the oxygenate removal rate drops.

(3) Oligomerization

The C₃-C₉ fraction from the oxygenate removal reactor was fed into a oligomerization reactor loaded with a MCM-22 catalyst, at operating conditions: WHSV of 3 h−1, Temperature at 200° C. The effluent contained: >85 wt % iso-olefins, with <15 wt % alpha-olefins, <5 wt % paraffins, and <1 wt % oxygenate. After distillation, the product had a boiling range of 150-350° C. with a carbon number range of C₉-C₂₅.

(4) Hydrogenation (HYD)

The effluent from the oligomerization reactor and the C₉₊ fraction from the reduction reactor were sent to full hydrogenation (HYD) in a hydrogenation reactor loaded with nickel based catalyst, where all unsaturation are hydrogenated at a WHSV of 3 h−1, temperature of 200° C. with a pressure of 450 psig, the hydrogen-to-olefin ratio is at 2:1. The resulting stream contained: >95 wt % n-paraffins and iso-paraffins; and <5 wt % aromatics and cycloparaffins and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅.

(5) Final Blending

The product stream from HYD was distilled and blended to provide a paraffinic diesel fuel containing: contained 75 wt % of iso-paraffin and 25 wt % of n-paraffin and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅.

Example 4: Process of Making Fully Formulated Diesel Fuel Using a Reforming Catalyst

A fully formulated diesel fuel composition was prepared according to a scheme shown in FIG. 5, which incorporates a reforming catalyst to generate the aromatics in the fuel composition. In this pathway, aliphatic hydrocarbons are derived from both reduction and oligomerization, while aromatics and cycloparaffins are produced via alkylation. This process utilizes the light carbon fractions that are not used in other pathways, which leads to a higher yield.

(1) CO₂ Hydrogenation (Reduction) and Separation

A feed mixture of CO₂ and hydrogen was fed into a reduction reactor loaded with metal oxide catalysts, operating optionally in recycle mode, the process effluent will undergo separations involving pressure swing adsorptions, and naphtha wash to separate the H₂, CO₂ and CO, CH₄ from the rest of the hydrocarbon stream. The unreacted H₂ and CO₂ alone with CO and CH₄ were fed back into the reduction reactor. Certain venting was needed to control the level of CH₄ build up in the recycle loop. The hydrogen-to-CO₂ molar ratio in the feed is at 3:1, with a GHSV of 4000 h−1 and a temperature of 300° C. The reactor effluent contained: 60-80 wt % unreacted CO₂ and hydrogen: 2-10 wt % CO: 15-30 wt % aliphatic hydrocarbons (C₁-C₂₅, >80% linear, paraffinic and olefinic): <2 wt % aromatics and cyclic hydrocarbons; and 2-5 wt % oxygenates. The stream was separated into two fractions: (i) C₉₊ fraction (boiling point >150° C.) that was sent to a hydrogenation reactor; and (ii) C₃-C₉ hydrocarbons sent to the oxygenate removal reactor (details below).

(2) Oxygenate Removal

The C₃-C₉ fraction contained: >95 wt % hydrocarbons (≥60% olefinic, remainder paraffinic), and <5 wt % oxygenates. This feed was processed in an oxygenate removal reactor loaded with SAPO-11 zeolite catalyst, at operating conditions: WHSV: 3 h⁻¹, Temperature: 350° C., Pressure: 200 psig, The resulting effluent contained: hydrocarbons (C₁-C₁₈) (>70 wt % olefinic, <30 wt % paraffinic), <5 wt % aromatics and cycloparaffins, and <1 wt % oxygenates. The effluent was separated into: C₃-C₅ fraction sent to the alkylation reactor; and C₃-C₉ fraction directed to an oligomerization reactor. The oxygenate removal reactor needed regeneration using diluted air or air at over 600° C. to remove the coke once the oxygenate removal rate drops.

(3) Alkylation

The alkylation reactor receives the effluent from the reforming reactor (described below) and the C₃-C₅ fraction from the oxygenate removal reactor. The alkylation reactor was loaded with aMCM-22 catalyst, at operating conditions: WHSV: 5 h−1, Pressure: 500 psig, Temperature: 250° C. The effluent contained: >95 wt % alkyl aromatics and cyclo-aromatics; and <5 wt % olefinic hydrocarbons. After distillation, the product has a boiling range of 150-350° C. and a carbon number range of C₉-C₂₅.

(4) Oligomerization

The C₃-C₉ fraction from the oxygenate removal reactor was fed to an oligomerization reactor. The reactor loaded with a MCM-22 catalyst at operating conditions: WHSV of 3 h⁻¹, Temperature: 250° C. The effluent contained: >85 wt % iso-olefins, with <15 wt % alpha-olefins, <5 wt % paraffins, and <1 wt % oxygenate. After distillation, the product had a boiling range of 150-350° C. with a carbon number range of C₉-C₂₅.

(5) Selective Hydrogenation (HYD 1)

The effluent from the alkylation reactor was split and one portion was sent to selective hydrogenation (HYD 1) in a hydrogenation reactor loaded with nickel, palladium, or platinum based catalyst. In this HYD 1, only olefins were hydrogenated, preserving most aromatics. The process was operated at a WHSV of 4, temperature of 150° C. with a pressure of 300 psig, the hydrogen to olefin mole ratio is at 1.5:1. The resulting stream contained: aromatics: >85 wt %, cycloparaffins: <10 wt %, and aliphatic paraffins: <5 wt %, and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅. Light and medium hydrocarbon paraffins (C₃-C₉) in the effluent were separated and fed to the reforming reactor for aromatization.

(6) Full Hydrogenation (HYD 2)

The remaining portion of the effluent from the alkylation reactor was combined with the effluent from the oligomerization reactor and the C₉₊ fraction from the reduction reactor and sent to full hydrogenation (HYD 2) in a second hydrogenation reactor loaded with nickel based catalyst, where all unsaturation are hydrogenated. The process was operated at a WHSV of 3, temperature of 200° C. with a pressure of 450 psig, the hydrogen to olefin mole ratio is at 3:1. The resulting stream contained: n-Paraffins and iso-paraffins: >60 wt %, Cycloparaffins: <40 wt %, and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅. Medium hydrocarbon paraffins (C₃-C₉) in the effluent were separated and fed to the reforming reactor for aromatization.

(7) Aromatization (Reactor Loaded with Reforming Catalyst)

The paraffinic light hydrocarbon streams from the HYD 1 and HYD 2 processes are combined and fed into a reforming unit loaded with Ga-modified ZSM-5 catalyst, at operating conditions: WHSV: 3 h⁻¹, Temperature: 550° C., Pressure: <150 psig, the resulting effluent included: gaseous products (C₃-C₅ paraffins (which will be recycled) and minor olefins); and liquid products. The liquid products included: 50-70 wt % benzene, toluene, and xylenes (BTX); 30-40 wt % C₉₊ aromatics, and <10 wt % paraffinic and olefinic hydrocarbons. The reforming reactor needed a regeneration cycle using diluted air or air at over 600° C. to remove the coke once the paraffin conversion rate drops

(8) Final Blending

The product streams from HYD 1 and HYD 2 were blended to provide a fully formulated diesel fuel containing: 12 wt % aromatics, 24 wt % cycloparaffins, 34 wt % of iso-paraffins and 30 wt % of n-paraffins, and had a boiling range: 150-350° C., with a carbon number range: C₉-C₂₅.

While specific embodiments of the subject invention have been discussed, the above specification is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this specification and the claims below. The full scope of the invention should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations.