PYROLYSIS REACTOR APPARATUS WITH INJECTION SYSTEM AND METHOD FOR MODIFICATION OF PYROLYZED FEEDSTOCK

Description

FIELD OF THE INVENTION

The present invention relates to an apparatus and method suitable for pyrolysis of alternative feedstocks, such as waste plastics, biomass, waste oils, and the like, wherein the pyrolysis apparatus system includes an injection system that selectively adds injectants to one or more of a headspace or vapor space of the pyrolysis reactor and a feedstream located upstream from the pyrolysis reactor during use that react with or otherwise influence pyrolysis reaction products in the headspace or vapor space in order to produce desirable products and/or control formation of undesirable compounds for example by preventing certain headspace reactions from occurring or reducing the frequency of such reactions.

BACKGROUND OF THE INVENTION

Pyrolysis of alternative feedstocks is challenging in part due to the many reactions that occur in the solid, liquid, and vapor phases, and the many different compounds that can and will be formed at any given pyrolysis condition. Additionally, alternative feedstocks typically contain many compounds, such as catalysts, or elements that can be considered contaminants. This leads to the formation of undesirable compounds or families of compounds that can reduce product quality, make waste products, or lead to operability challenges in the process.

Various prior art documents disclose addition of numerous different substances such as liquids and gases to different portions of a polymer processing system for diverse reasons.

U.S. Pub. 2016/001732 A1 discloses an apparatus and method for pyrolyzing hydro carbonaceous materials to reportedly produce useful vapor and solid products comprising a generally cylindrical, linear reactor having a screw means for transporting hydrocarbonaceous materials through said reactor, means for feeding and heating said hydrocarbonaceous materials whereby they are processed and pyrolyzed to produce vapor and solid products.

To reportedly promote and accelerate vapor movement, and to minimize the tendency for excessive heat to rise in the open headspace of a reactor in declining orientation, thereby potentially over-cracking vapor-phase molecules, a portion of the non-condensable gas discharged from the final condenser can be optionally re-injected into the reactor at injection port 400 and/or steam withdrawn from vent 200 can be optionally re-injected into the reactor at injection port 400.

Optionally, for example, in cases where accelerated evacuation of product vapor from the reactor 10 is desired, and depending upon the product mix desired, a non-condensable carrier gas can be introduced into the coldest portion of Zone 5 501 at purge gas port 500. Such non-condensable carrier gas is comprised of nitrogen and/or a recycled non-condensable gas fraction resulting from operation of the invention and/or methane from natural gas.

In situ derived water, recovered from moisture entering the primary thermal reactor with the raw hydrocarbonaceous material and created by chemical reactions in the primary thermal reactor and elsewhere, can be separately recovered from the bottom of the knockouts 821, 823 and 825 as depicted in FIG. 2, passed over a carbon bed to adsorb dissolved aromatic hydrocarbon compounds, and subsequently vaporized to steam using waste heat from the genset, if deployed, from direct-fired heating of the reactor, and/or from elsewhere. Optionally, some portion of this steam can be returned to the process at injection port 400 located either in Zone 3 (as depicted in FIG. 1) or in Zone 4, or alternatively injected in Zone 5 purge gas port 500 to promote the water-gas shift reaction. Alternatively, it can be routed to the air pollution control system as steam.

U.S. Pub. 2012/0065440 A1 relates to an apparatus and method for thermolysis of waste plastics where reaction residue and carbonization products are removed continuously. The apparatus includes a plastic feeding system (1), the extruder (2), and pyrolysis reactor (3) which is equipped in dual propeller (7) and connected to external circulation loop (4) with flux heating (5), circulation pump (6) and three-way valve (8). A method is disclosed wherein plastic waste is continuously fed to the reactor where at 350-450° C. at mixers' 30-1500 rpm, the thermolysis is carried then molten plastic in volume 4-10 m3/h is pumped to flux heater with heating power 60-120 KW from where with regulated operating temperature reaction mixture of vapors and liquids is fed back to reactor but products vapors are removed continuously from reactor and condensed in another part of system and reaction by-products are returned to main thermolysis reactor and thermolysis leftovers are received continuously through heat exchanger by three-way valve situated before the flux heater to residue tank.

U.S. Pub. 2010/0319255 A1 relates to system(s) and process(es) to produce synthesis gas from feedstock through, in part, multi-phased gasification and steam reformation. In the multi-phased gasification, an amount of feedstock is supplied to a pyrolysis chamber in which high-pressure pyrolysis at a first temperature reforms into gas at least a portion of the amount of feedstock; the gas includes synthesis gas (syngas). An amount of feedstock by-product that results from the high-pressure pyrolysis is conveyed to a solids reactor functionally coupled to the pyrolysis chamber. At least a portion of the amount of feedstock by-product is reformed into syngas at high-pressure and a second temperature within the solids reactor; an amount of disposable solids is ejected from the solids reactor. Gas produced in the pyrolysis chamber or syngas produced in the solids reactor is saturated via steam reformation and cleaned. Clean syngas is reportedly supplied for fuel production.

WO 2005/083041 A1 relates to a reactor for thermal processing of waste from additional materials (6), comprising a closed container (36) for gasifying, pyrolyzing or thermolyzing the additional materials, an essentially gasproof device (4) which is used to guide the additional materials into the container, gas guiding means (32, 34, 38, 40, 42) for the controlled withdrawal of gas from the container, such that pressure in the container can be adjusted to above the atmospheric pressure.

IN 2021310184 A relates to a reactor apparatus for pyrolyzing plastic feedstock, the apparatus including a reactor component comprising a refractory material such as stainless steel, quartz, or any other refractory material able to withstand high temperatures with the refractory material having a melting point above 1450. In some embodiments, the reactor component comprises a single-phase electrical heating mechanism of up to 1200 with a control unit for precise control over various parameters. The reactor component also fitted with a gas supply mechanism and a low-cost water cooling system with an innovative dual-channel cooling mechanism. In other aspects, this method of synthesizing MWCNTs with maximum 44% yield and H2 gas from waste plastic using the pyrolysis reactor system is disclosed. The method comprises the steps of providing a high-temperature environment for pyrolyzing plastic feedstock in the apparatus comprising the above refractory trial. In other aspects, a design within the reactor system to convert toxic gasses to nontoxic emissions, which will otherwise be released during the pyrolysis process, thereby being environmentally compliant.

In view of the above, there is still a need in the art to be able to control the formation of undesirable compounds in the pyrolysis reactor, in particular in the headspace or vapor space of the reactor, above solid and/or melted feedstock and the uppermost extent of the conveyor which transports the feedstock longitudinally through the reactor.

SUMMARY OF THE INVENTION

This need and others is solved by the apparatus and method of the present invention which includes a pyrolysis reactor apparatus with an injection system that selectively adds injectants to one or more of i) the headspace or vapor space of the pyrolysis reactor vessel and ii) a feedstream conduit located outside of and upstream from the pyrolysis reactor during use where the injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock in the reactor vessel.

As utilized herein, the terms “pyrolysis reactor”, “pyrolytic reactor”, “reactor”, and “reactor vessel”, and the like are synonyms.

The terms “headspace” and “vapor space” and the like are also synonyms and define a volume of gas and/or vapor above the solid, melted and/or liquid material derived from feedstock within the pyrolysis reactor.

Addition of injectant materials into the pyrolysis reactor is provided to control the formation of undesirable compounds, e.g. oligomers and/or polymers, in some embodiments or promote the formation of desirable compounds, or both.

The materials injected may or may not be catalytic, but affect the vapor space conditions to promote or inhibit compound formation. It is to be understood that one or more of the feedstream components may contain small trace amounts of a residual catalyst originally used to produce a polymer present in the feedstream. The injectant can be used to prevent certain headspace reactions with the catalyst or at least reduce the frequency of such reactions.

In addition to the chemical reaction, the mechanism may also produce physical effects, such as cooling the reaction or changing the temperature profile in the reaction. It may be thermodynamic such as by changing the partial pressure of components in the vapor space.

The injectant components that are added should not require separation or disposal after the reaction, or reduce the yield of the reaction overall.

The location where the injectants are introduced in the reactor can have other impacts. For example, when one injects the injectant near the downstream end of the reactor, early time phase reactions such as dichlorination have already occurred and those associated compounds will not participate in other reactions or effects. Conversely, when one introduces injectant at the feed end of the reactor, in the vapor space, then you are able to influence one or more of the early time phase reactions and promote cracking reactions earlier.

Examples of impacts that can be had on the product include shifting of the carbon number distribution to be lighter or heavier, or narrower. Certain compounds may be chemically impacted such as decarboxylation of acids, or addition reactions to double bonds, or further cracking of larger molecules. Some added injectants also are able to remove heavy metals, which are undesirable in finished products, or halides and other heteroatoms.

The injected materials can be liquid, vapor, or solids, and may or may not undergo a phase change after being injected into the reactor. Some applications may allow reuse of the injection material.

The injectants can be injected through an injection quill, or a standard pipe nozzle, or solids through an airlock mechanism, by way of nonlimiting example.

In some embodiments, the added injectants can be used to inhibit the release of hydrocarbons from the reactor during addition of feedstock or removal of inert material. For example, nitrogen added to the reactor can help positively pressurize the inlet ensuring that hydrocarbon vapors do not overcome the pressure differential and leak out to the atmosphere from the feedstream conduit.

In further embodiments, the injected materials when reacted with pyrolysis reaction products affect the physical properties of compounds in the product. For example, the injected material make a common foulant less “sticky’ in the downstream sections of the process and lead to less maintenance.

In one embodiment or aspect, a pyrolysis reactor apparatus for polymer feedstock is disclosed and comprises a pyrolytic reactor vessel having a longitudinal length running from a first end to a second end in a longitudinal direction of the vessel; wherein the vessel has a free volume headspace of at least 60% of the total volume of the vessel when the vessel has feedstock therein; a conveyor located in the vessel that agitates at least one portion of the feedstock and transports the at least one portion in the longitudinal direction through the vessel from a first zone to a second zone, wherein the first zone is upstream from the second zone in a process flow direction; an injection system comprises: a first injection port located in the free volume headspace of the vessel that can supply at least one injectant that is one or more of a solid, vapor and liquid into the free volume headspace, whereby the at least one injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock, otherwise influences pyrolysis reaction products in the free volume headspace; a second injection port located in the free volume headspace of the vessel that can supply at least one or more of a solid, vapor or liquid injectant into free volume headspace downstream from the first injection port, whereby the at least one second injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock, otherwise influence pyrolysis reaction products in the free volume headspace; and a conduit system connected to the injection ports wherein the injection system selectively distributes the injectant to the injection ports through the conduit system during pyrolysis of the feedstock.

In a further aspect or embodiment, the injectant is one or more of steam, an alcohol, an acid, a chain terminator, and radical scavenger, and the at least one second injectant is one or more steam, an alcohol, an acid, a chain terminator, and radical scavenger.

In still a further aspect or embodiment, the injectant is one or more of an alcohol, an acid, a chain terminator, and radical scavenger, and the at least one second injectant is one or more of an alcohol, an acid, a chain terminator, and radical scavenger.

In a further aspect or embodiment, the injection system further includes a supply container that houses the at least one injectant, and wherein the conduit system is connected between the supply container and the first injection port.

In yet a further aspect or embodiment, the pressure in the reaction vessel is less than 25 psi, and the first zone and the second zone have a temperature less than 1,200°F.

In a further aspect or embodiment, the headspace extends above an uppermost surface of the conveyor.

In another aspect or embodiment, the pyrolysis reactor vessel includes at least one outlet in the headspace for pyrolytic product gases to exit the pyrolysis reactor vessel located between the first injection port and the second injection port.

In still another aspect or embodiment, at least a second outlet is present in the headspace downstream in the pyrolytic reactor vessel from the second injection port.

In a further aspect or embodiment, the pyrolysis reactor vessel, the at least one injectant and the at least one second injectant are free of a catalyst other than a catalyst inherently present in the feedstock.

In yet another aspect or embodiment, an injection port is located in a feedstream conduit for the feedstock that can supply a third injectant into the feedstream prior to the feedstock entering the vessel.

In another aspect or embodiment, a pyrolysis reactor apparatus for polymer feedstock comprises: a pyrolytic reactor vessel having a longitudinal length running from a first end to a second end in a longitudinal direction of the vessel; wherein the vessel has a free volume headspace of at least 60% of the total volume of the vessel when the vessel has feedstock therein; a conveyor located in the vessel that agitates at least one portion of the feedstock and transports the at least one portion in the longitudinal direction through the vessel from the first zone to the second zone; an injection system comprises: a first injection port located in a feedstream conduit for the feedstock that can supply a first injectant into the feedstream conduit prior to the feedstock entering the vessel from the feedstream conduit; and a second injection port located in the free volume headspace of the vessel that can supply a second injectant into the free volume headspace, whereby the second injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock, or otherwise influence pyrolysis reaction products in the free volume headspace; a conduit system connected to the injection ports, and wherein the injection system selectively distributes the first injectant to the first injection ports and the second injectant to the second injection port through the conduit system during pyrolysis of the feedstock.

In yet a further aspect or embodiment, steam is injected through the first injection port to assist in preventing vapor from the reactor vessel moving upstream towards a feed hopper through the feedstream conduit.

In yet a further aspect or embodiment, the first injectant is one or more of steam, an alcohol, an acid, a chain terminator, and radical scavenger, and the second injectant is one or more of steam, an alcohol, an acid, a chain terminator, and radical scavenger.

In still a further aspect or embodiment, the second injectant is one or more of an alcohol, an acid, a chain terminator, and radical scavenger.

In another aspect or embodiment, a method for influencing pyrolysis reaction products in a headspace of a pyrolysis reactor apparatus comprises the steps of: obtaining a pyrolysis reactor, supplying the at least one injectant into the free volume headspace of the pyrolytic reactor vessel from the first injection port, whereby the injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock, or otherwise influence pyrolysis reaction products in the free volume headspace; supplying at least one second injectant into the free volume headspace of the pyrolytic reactor vessel from the second injection port whereby the injectant participates in a vapor phase chemical reaction product of the feedstock.

In a further aspect or embodiment, the method includes the step of injecting the at least one injectant and the at least one second injectant into the free volume headspace simultaneously.

In another aspect or embodiment, the method includes the step of injecting the at least one injectant and the at least one second injectant into the free volume headspace sequentially.

In another aspect or embodiment, the injection is performed for a period of time greater than 30 seconds but less than 5 minutes, continuously.

In a further embodiment, the period of time ranges from 2 to 4 minutes.

In yet a further embodiment, the feedstock has a residence time in the vessel of at least 40 minutes.

For the avoidance of doubt, it is understood that while various embodiments or aspects of the invention are described individually, it should be clear that two or more embodiments or aspects can be, and often times are, present in a single apparatus or method according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will become apparent to those skilled in the art to which the present disclosure relates upon reading the following description with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a pyrolysis reactor apparatus of the present invention including one embodiment of an injection system; and

FIG. 2 is a schematic view of a further embodiment of a pyrolysis reactor apparatus of the present invention including an injection system.

DETAILED DESCRIPTION OF THE INVENTION

The pyrolysis reactor apparatus of the present invention processes and converts polymer materials, preferably polymer waste or feedstock to useful end products that are petroleum based. Examples of products that can be produced directly or indirectly through further refining include, but are not limited to, waxes, naphtha, distillate, diesel fuel, oil, gasoline, heating oil, natural gas, kerosene, lubricants, and various gas products such as alkanes, e.g. methane, ethane, propane, butane, pentane, and alkenes, as well as isomers thereof.

The pyrolysis reactor apparatus includes a novel injection system that introduces at least one injectant into the reactor vessel during processing of the feedstock, wherein the injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock during the pyrolysis process. Methods of reacting the injectant with a reaction product of the feedstock in a vapor phase within the pyrolytic reactor vessel are disclosed.

The invention thus provides an apparatus and a method for conducting vapor phase reactions between pyrolysis reaction products and one or more injectants which in turn influence final product composition. The injectant-pyrolysis product vapor phase reaction allows for control of the makeup of the resulting vapors, and thus, the final condensed oil. In a preferred embodiment, the injectants do no affect the pyrolysis zone, but the vapor phase, post pyrolysis, namely with pyrolytically-produced hydrocarbons.

The feedstock preferably predominantly includes two or more different polymers and is preferably polymer waste or scrap obtained from post-consumer and/or post-manufacturing that is by way of example only, one or more of not suitable for its intended purpose or has been already used for its intended purpose. The polymer materials can be one or more of thermoplastic polymers, thermoset polymers, and biopolymers.

Examples of suitable feedstock polymer materials include, but are not limited to, polyethylene, polypropylene, polyester, acrylonitrile-butadiene-styrene (ABS) copolymers, polyamide, polyurethane, polyether, polycarbonate, poly(oxide), poly(sulfide), polyarylate, polyetherketone, polyetherimide, polysulfone, polyurethane, polyvinyl alcohol, and polymers produced by polymerization of monomers, such as, for example, dienes, olefins, styrenes, acrylates, acrylonitrile, methacrylates, methacrylonitrile, polymers of diacids and diols, lactones, polymers of diacids and diamines, lactams, vinyl halides, vinyl esters, block copolymers thereof, and alloys thereof. Polymers yielding halogenated material upon pyrolysis, for example, polyvinyl chloride, polytetrafluoroethylene, and other halogenated polymers, can be corrosive but can be tolerated.

Polymer materials can also include thermoset polymers such as, for example, epoxy resins; phenolic resins; melamine resins; alkyd resins; vinyl ester resins; unsaturated polyester resins; crosslinked polyurethanes; polyisocyanurates; crosslinked elastomers, including but not limited to, polyisoprene, polybutadiene, styrene-butadiene, styrene-isoprene, ethylene-propylene-diene monomer polymer; and blends thereof.

Feedstock polymer materials can also include sustainable biomaterials such as biopolymers. Biopolymers can be sustainable, carbon neutral and renewable, because they are made from plant materials which can be grown indefinitely. These plant materials come from agricultural non-food crops. Examples of biopolymers include, but are not limited to, polylactic acid (PLA) and polyhydroxyalkanoate (PHA) which are used in a multi-layer sheet for food packaging applications.

Polymer material found in scrap material can have a combination of thermoplastic and thermoset polymers, for example, tires, paint, adhesive, automotive shredder waste (fluff), etc., and can be used as feedstock for the pyrolytic apparatus and process described herein.

The polymer feedstock often includes one or more of contaminants, processing aids, fillers, pigments, flame retardants, clay, and the like. Generally, the amount thereof is about 2% to about 25% by weight, and preferably less than about 20 or 15 wt. %, based on the total weight of the feedstock. Preferably such compounds are not chemically or physically reacted and therefore pass through the pyrolysis reactor apparatus and are emitted from the reactor vessel at the end of the process, often as a solid inert residue.

Turning now to the drawings, wherein like reference numbers are utilized to designate similar or the same components throughout the several views, FIG. 1 schematically illustrates a pyrolysis reactor apparatus 10 of one embodiment of the invention for carrying out pyrolysis of polymer feedstock 20. The apparatus includes a pyrolytic reactor vessel 30 for conversion of polymer feedstock to useful products. The pyrolytic reactor vessel is a preferably substantially cylindrical, linear, heated vessel having a longitudinal length running from an upstream first or feed end 32 to a second or downstream end 34 and a width perpendicular to the length. The apparatus can operate in a continuous or batch manner as desired by the end user. The pyrolytic reactor vessel thus has a process flow path running from the first end 32 to the second end 34 in the longitudinal direction of the vessel. When loaded with feedstock, for example for a feed hopper 11 located upstream from reactor vessel 30, the reactor vessel has a free volume headspace 60 that may include non-solid materials such as vapors and gases.

Reactor Vessel

In one embodiment, the reactor vessel 30 can be a double-walled apparatus that includes an outer shroud 36 substantially surrounding the reactor vessel 30. The reactor vessel is preferably non-rotatable. The outer shroud is spaced a distance from wall 38 of the vessel. In some embodiments one or more barrier walls 39 are present and extend between the reactor vessel and outer shroud thereof to define fluid channels. When the barrier wall(s) is/are present, the fluid channels permit a heat exchange medium for example a gas, to be circulated or channeled as desired along the exterior wall of the reactor vessel, between the reactor vessel and the outer shroud. Insulation is optionally present on the exterior of the outer shroud to reduce thermal losses and improve thermal efficiency of the process.

Heat is supplied to the vessel via one or more conventional heating units 50. A heating unit can be present in each area to be heated within the vessel or one heating unit 50 may serve multiple areas of the vessel. Heat generated by the heating units 50 generally travels around the circumference of the substantially cylindrical vessel and exits therefrom through heat exhaust channels 52 at the top of the vessel 30. The heat in the different sections of the vessel volatilizes the feedstock, which enters the vapor space or headspace 60 of the vessel 30 and can exit the vessel 30 through outlets 62.

In a preferred embodiment, located within the vessel is a conveyor 70 that agitates at least one portion of the feedstock and transports the feedstock in the longitudinal direction through the vessel towards second end 34. The conveyor can be in the form of one or more of an auger, screw and helical stirrer, by way of non-limiting example. Much of the headspace 60 is located above conveyor 70, as illustrated.

In order to produce desired products, the reactor vessel 30 is preferably operated within pressure range from about 1 psi to less than 25 psi.

During operation, the temperature inside the reactor vessel 30 is controlled in order to exceed the melting temperature or glass transition temperature of the polymers in the feedstock. The temperature inside the reactor vessel will vary from the base of the reactor, which is in contact with the polymer melt and residual solids, to the top of the reactor which includes the free volume headspace 60. The temperature can also vary in different heating zones. That said, the maximum temperature achieved within the vessel at any location is generally less than 1,200°F.

In an important aspect of the present invention, the pyrolysis reactor apparatus 10 does not incorporate any catalyst therein for pyrolysis of the feedstock 20. The reactor vessel is free of any added catalyst. However, it is to be understood that the polymer feedstock may include some catalysts in its composition.

Examples of suitable pyrolysis reactor vessels and conveyors are set forth in U.S. Pat. Nos. 10,711,202; and 11,118,114; and U.S. Patent Application Publication No. 2022/0064533, all herein fully incorporated by reference.

Injection System

The pyrolysis reactor apparatus of the invention advantageously includes an injection system 100 that introduces injectants 110 into the headspace 60 of the pyrolysis reactor vessel 30 during use, where the injectant participates in a vapor phase chemical reaction with a reaction product of the feedstock in the reactor vessel.

In a further embodiment, the injectants 110 can be introduced into the feedstream 22 for feedstock 20 prior to the feedstock 20 entering the reaction vessel 30. It should be understood that the injectants can be both injected into the headspace 60 as well as into feedstream 22 in some embodiments of the invention.

The injectant materials react in the vapor phase to control the formation of undesirable compounds and promote the formation of one or more of desirable compounds.

The injection system 100 includes a plurality of injection ports 120. A first vessel injection port 122 is located in the free volume headspace of the vessel 30 in order to supply an injectant into the headspace 60. At least one second injection port 124 is included and located in the free volume headspace of the vessel downstream from the first injection port 122 and can supply an injectant into the free volume headspace. A third injection port 126 is also illustrated in the figures which is located even further downstream from the second injection port 122 and is suitable for supplying an injectant into the free volume headspace 60.

In one embodiment, for example as illustrated in both FIGS. 1 and 2, an injection port, for example first injection port 122, is located upstream from at least one outlet 62 and preferably all outlets 62 through which pyrolysis product gases can exit vessel 30. Still further, an injection port 120 which is not first injection port 122, is located downstream from one or more outlets 62. Second injection port 124 is also located downstream from additional outlets 62 in vessel 30. Third injection port 126 is preferably located upstream from at least one outlet 62 of vessel 30. In some embodiments, at least two different outlets 62 are located between adjacent injection ports as also illustrated in FIGS. 1 and 2. Thus, it should be clear that the injection system configuration provides a myriad of configurations to influence pyrolysis reaction products in the headspace in order to produce desirable products and/or control formation of undesirable compounds.

Following from the above paragraph, it should also be clear with reference to the drawings that the same or different injectants can be injected through different injection ports both upstream and downstream from a particular outlet 62. Likewise, two or more outlets 62 can be located both upstream and downstream from a particular injection port.

FIG. 1 also illustrates a feedstream injection port 128 which supplies an injectant into feedstream conduit 22 containing feedstock 20. In a process flow direction feedstream conduit 22 and feedstream injection port 128 is located upstream from all injection ports, e.g. 122, 124 and 126 directly connected to the reactor vessel 30.

A conduit system 130 is connected to the injection ports. Depending upon the effect to be achieved, each injection port 120 may or may not be in fluid communication with another injection port. In one embodiment, the first injection port 122 has its own conduit system 130 that is separate and distinct from a second conduit system 130 that is connected to the second injection port 124 and any other additional conduit system present. In this manner, two or more different injectants can be supplied to the headspace 60 of the pyrolytic reactor vessel.

In still other embodiment, for example as shown in FIG. 2, a single conduit system 130 is connected to the first injection port 122 and the second injection port 124, whereby a single injectant can supply both the first injection port and the second injection port. This embodiment is quite useful when simultaneous injection of the injectant is desired in different zones, for example the first zone and the second zone.

In yet a further embodiment, for example as illustrated in FIG. 2, two or more injection ports 122, 124 are connected by a first conduit system 130, and a third injection port 126 is isolated from the first injection port and second injection port and further includes its own conduit system 130.

In a further embodiment of the invention, one or more and preferably all of the injection ports independently contain or are operatively connected to a valve such as a check valve 132 that prevents gas or vapors within the pyrolytic reactor vessel from entering the conduit system upstream from the injection ports.

In one embodiment, the injection system 100 further includes a supply container 140 that houses the at least one injectant. The conduit system 130 is connected between the supply container and the injection system ports. In one embodiment, a first supply container 142 is operatively connected to the first injection port 122 and a second supply container 142 is operatively connected to the second injection port 124. The first and second supply containers can supply the same or a different injectant as desired.

In one embodiment, a controller 150 is utilized to selectively distribute the injectant to the injection ports through the conduit system during pyrolysis of the feedstock. The controller can include one or more of a microprocessor, CPU, and the like.

Injection of the injectant is performed such that there is a suitable period of time in order to facilitate reaction with a reaction product of the feedstock in the vapor phase of the free volume headspace 60. In some embodiments, the injection point allows residence time in the reactor that ranges from about 30 seconds to about 60 minutes, desirably from about 45 seconds to about 10 minutes, and preferably from about 2 minutes to about 4 minutes.

In other embodiments, intermittent or continuous injection can be utilized.

Injectants

Vapor phase reactions are achieved by providing the injectant into the vessel headspace whereby it reacts with a reaction product of the feedstock. Depending upon the chemical reaction desired, different injectants can be utilized, along with different amounts of the injectants. A single injectant can be utilized in a single port or multiple injectants can be introduced simultaneously through the same port. In some embodiments, the injectant lowers the temperature in a localized area of the vapor space 60. In other embodiments, the injectant raises the local temperature in a localized area of the vapor space 60.

In a desired embodiment, injectants are one or more of an alcohol, an acid, a chain terminator, steam, a radical scavenger, and other polar and non-polar additives. Preferably, the injectant is one or more of an alcohol, an acid, a chain terminator, and radical scavenger.

In one embodiment, the injectant is free of steam, especially steam that has been produced by the pyrolysis reactor apparatus. Stated in another manner, in a preferred embodiment there is no recirculation of steam produced in the pyrolytic reactor vessel that is utilized as an injectant and reinjected into the vessel.

While in accordance with the patent statues, the best mode and preferred embodiment have been set forth, the scope of the invention is not limited thereto, but rather by the scope of the attached claims.