METHODS AND SYSTEMS FOR SEPARATING WATER AND HEAVY HYDROCARBONS FROM AN INLET GAS STREAM

Description

BACKGROUND

Field

Embodiments disclosed herein relate generally to separating water and heavy hydrocarbons from an inlet gas stream for Natural Gas Processing and/or Liquefied Natural Gas (LNG) production.

Description of the Related Art

Natural Gas is processed at gas processing and/or LNG liquefaction plants. At these plants, an inlet gas stream goes through a number of processes to ultimately become processed Natural Gas or LNG ready for commercial usage. Occasionally, this inlet gas stream includes an undesirable amount of water and/or heavy hydrocarbons (e.g. hydrocarbons with an exemplary chemical formula C_xH_y where x≥6). The water and heavy hydrocarbons need to be sufficiently removed before subsequent processes, such as the liquefaction process. Water and heavy hydrocarbons can solidify and foul exchangers at cryogenic temperatures experienced in the liquefaction process.

As such, there is a continuous need for systems and methods for removing water and heavy hydrocarbons from an inlet gas stream.

SUMMARY

In one or more embodiments, a mol sieve system comprises a first set of mol sieve vessels and a second set of mol sieve vessels fluidly coupled to and located downstream of the first set of mol sieve vessels. The first set of mol sieve vessels includes a first mol sieve vessel and a second mol sieve vessel. Each of the first mol sieve vessel and the second mol sieve vessel include a first mol sieve bed including a first porosity size configured to remove water from a working fluid and a second mol sieve bed disposed below the first mol sieve bed including a second porosity size configured to remove heavy hydrocarbons from a working fluid. The second set of mol sieve vessels includes a third mol sieve vessel and a fourth mol sieve vessel. Each of the third mol sieve vessel and the fourth mol sieve vessel include a third mol sieve bed including a third porosity size configured to remove water from the working fluid.

In one or more embodiments, a method for removing water and heavy hydrocarbons from an inlet gas stream comprises adsorbing water and heavy hydrocarbons from an inlet gas stream by flowing the inlet gas stream through a first mol sieve vessel, wherein the adsorbed water and heavy hydrocarbons are collected in the first mol sieve vessel; removing water and heavy hydrocarbons from a second mol sieve vessel by flowing a regeneration gas stream through the second mol sieve vessel, wherein the regeneration gas stream comprises at least a portion of the inlet gas stream, and wherein the regeneration gas stream leaving the second mol sieve vessel comprises at least a portion of the water and the heavy hydrocarbons from the second mol sieve vessel; separating out the water from the regeneration gas stream by flowing the regeneration gas stream through a first separation device fluidly coupled to and located downstream of the second mol sieve vessel; and separating out the heavy hydrocarbons from the regeneration gas stream by flowing the regeneration gas stream through a second separation device fluidly coupled to and located downstream of the first separation device.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

FIG. 1 illustrates a schematic view of an exemplary molecular sieve system, according to one or more embodiments.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

Embodiments disclosed herein relate to systems and methods for the removal of water and heavy hydrocarbons from an inlet gas stream for processing, such as Gas Processing and/or liquefied natural gas (LNG) production.

FIG. 1 illustrates a schematic view of an exemplary molecular (mol) sieve system 100 for removing water and heavy hydrocarbons from a working fluid such as an inlet gas stream.

The mol sieve system 100 is configured to receive an inlet gas stream 101 and remove water 102 and heavy hydrocarbons 103 from the inlet gas stream 101 to produce a dry gas stream 104 with a reduced amount of water 102 and heavy hydrocarbons 103. The heavy hydrocarbons 103 include, but are not limited to, hydrocarbons represented by the exemplary chemical formula C_xH_y where x≥6 and y≥6, such as benzene.

The mol sieve system 100 includes, at least, a first set of mol sieve vessels 110 and a second set of mol sieve vessels 120. While each of the first set of mol sieve vessels 110 and the second set of mol sieve vessels 120 is only illustrated as having two mol sieve vessels each (e.g. the first set of mol sieve vessels 110 including a first mol sieve vessel 110a and a second mol sieve vessel 110b, and the second set of mol sieve vessels 120 including a third mol sieve vessel 120a and a fourth mol sieve vessel 120b), it should be understood that any number of mol sieve vessels may be utilized in each of mol sieve vessel sets 110, 120 such as 2, 3, 4, 5, 6, 7, 8, or more mol sieve vessels.

The first set of mol sieve vessels 110 each include one or more mol sieve beds 111 and are configured to remove water 102 and/or heavy hydrocarbons 103 from a working fluid (e.g. inlet gas stream 101). The mol sieve beds 111 adsorb water 102 and/or heavy hydrocarbons 103 from a working fluid (e.g. inlet gas stream 101) passing through them. The mol sieve beds 111 are configured to adsorb water 102 and/or heavy hydrocarbons 103 thus removing the water 102 and/or heavy hydrocarbons 103 from the working fluid such that the adsorbed water 102 and/or heavy hydrocarbons 103 are collected within the first set of mol sieve vessels 110a, 110b.

Molecular (mol) sieve beds (such as mol sieve beds 111 and 112) are porous and are used to adsorb water 102 and/or heavy hydrocarbons 103. Mol sieve beds may include beads or extrudate which are made of a zeolite powder and a binder. Mol sieve beds may be classified into type A zeolite beds and type X zeolite beds. The zeolite powder may include cations. The cations may include, but are not limited to, sodium, potassium, calcium, lithium, and magnesium. The cations used in a mol sieve bed determine the porosity size of the mol sieve bed, which determines the molecules the mol sieve bed can adsorb. In one example, a 3A mol sieve bed includes potassium (K+) cations which produce a porosity size of about 3 angstrom. Due to the porosity size, the 3A mol sieve bed will primarily only adsorb water. In another example, a 4A mol sieve bed includes sodium (Na+) cations which produce a porosity size of about 4 angstrom. Due to the porosity size, the 4A mol sieve bed will adsorb water and other molecules such as nitrogen, carbon dioxide, methanol, and hydrogen sulfide. In another example, a 5A mol sieve bed includes calcium (Ca2+) cations which produce a porosity size of about 5 angstrom. Due to the porosity size, the 5A mol sieve bed will adsorb water, nitrogen, carbon dioxide, methanol, hydrogen sulfide, methyl, and ethyl mercaptains. In another example, a 13× mol sieve bed includes sodium (Na+) cations with a porosity size of about 10 angstrom. Due to the porosity size, the 13× mol sieve bed will adsorb the molecules listed above in addition to heavy hydrocarbons 103, such as propyl and butyl mercaptains, sulfides, and/or BTX (e.g. benzene, ethyl benzene, xylene, toluene). Accordingly all previously mentioned mol sieve beds (e.g. 3A-5A and 13×) will adsorb water, but the larger porosity size molar sieve beds will also adsorb other components. When the mol sieve beds become saturated, the mol sieve beds will begin releasing heavier components (e.g. heavy hydrocarbons 103) and adsorb water in their place.

The mol sieve beds 111 may include 3A mol sieve beds, 4A mol sieve beds, 5A mol sieve beds, 13× mol sieve beds, or any combination thereof. The 3A-5A mol sieve beds are suited for adsorbing water 102 from a working fluid, and the 13× mol sieve beds are suited for adsorbing heavy hydrocarbons 103 from a working fluid. In one or more embodiments, the 13× mol sieve beds are also suited for adsorbing water 102 from the working fluid.

In one or more embodiments, the mol sieve beds 111 adsorb the water 102 and heavy hydrocarbons103, and the water 102 and heavy hydrocarbons are retained (e.g. collected) in the first set of mol sieve vessels 110. Accordingly, The first set of mol sieve vessels 110 may include mol sieve beds 111 sized to adsorb both water 102 and heavy hydrocarbons 103 from a working fluid, such as inlet gas stream 101 or a portion thereof. In one or more embodiments, the first set of mol sieve vessels 110 include a combination of one or more 3A, 4A, and/or 5A mol sieve beds (having a first porosity size), and 13× mol sieve beds (having a second, different porosity size), such as at least one 3A, 4A, and/or 5A mol sieve bed located above at least one 13× mol sieve bed. In such embodiments, the at least one 3A, 4A, and/or 5A mol sieve bed may be separated from the at least one 13× mol sieve bed by a material layer, such as a mesh or screen. In one or more embodiments, the first set of mol sieve vessels 110 include only one type of bed, such as one or more 13× mol sieve beds.

After some time, the mol sieve beds 111 within each of the first set of mol sieve vessels 110a and/or 110b will adsorb an amount of water 102 and/or heavy hydrocarbons 103 such that the mol sieve beds 111 are prevented from sufficiently adsorbing additional water 102 and/or heavy hydrocarbons 103 from the working fluid passing (e.g. flowing) through each of the first set of mol sieve vessels 110a and/or 110b. The mol sieve beds 111 may also begin to release previously adsorbed heavy hydrocarbons 103 back into the working fluid. When this occurs, the water 102 and/or heavy hydrocarbons 103 previously adsorbed (e.g. collected in each of the first set of mol sieve vessels 110a and/or 110b) should be removed from each of the first set of mol sieve vessels 110a and/or 110b to regenerate the mol sieve beds 111. The water 102 and/or heavy hydrocarbons 103 can be removed by heating the mol sieve beds 111 and/or flowing at least a portion of the working fluid, such as regeneration gas stream 106, through the mol sieve beds 111 and each of the first set of mol sieve vessels 110a and/or 110b in a direction typically opposite from flow during adsorption.

Accordingly, each of the first set of mol sieve vessels 110a and/or 110b, may either be in adsorption or regeneration. When in adsorption, the mol sieve beds 111 are used to adsorb water 102 and/or heavy hydrocarbons 103 thus removing the water 102 and/or heavy hydrocarbons 103 from the working fluid passing through the mol sieve vessels 110a and/or 110b. When in regeneration, a regeneration gas stream, such as regeneration gas stream 106, flowing through the mol sieve vessels 110a and/or 110b regenerates the mol sieve beds 111. For example, the regeneration gas stream may be a portion of the inlet gas stream 101 that has had water and/or heavy hydrocarbons removed by the mol sieve vessel 110a when in adsorption. The regeneration gas flowing through the mol sieve vessels 110a and/or 110b removes the water 102 and/or heavy hydrocarbons 103 previously adsorbed by the mol sieve beds 111 and collected in the mol sieve vessels 110a and/or 110b from the mol sieve vessels 110a or 110b. Regeneration may be used to regenerate the mol sieve beds 111 when the mol sieve beds 111 have adsorbed an amount of water 102 and/or heavy hydrocarbons 103 such that the mol sieve beds 111 are prevented from properly adsorbing more water 102 and/or heavy hydrocarbons 103 from the inlet gas stream 101. Each of the mol sieve vessels 110a or 110b may be cycled between adsorption and regeneration. In one or more embodiments, switching between adsorption and regeneration requires switching of flow directions through the mol sieve vessels 110a or 110b. Switching flow direction may be accomplished by, for instance, opening and closing of internal or external valves.

The second set of mol sieve vessels 120 each include one or more mol sieve beds 112. The mol sieve beds 112 adsorb water 102 from a working fluid (e.g. regeneration gas stream 106) passing through them. The mol sieve beds 112 are configured to adsorb water 102 from the working fluid and store the water 102 within the mol sieve vessels 120a, 120b thus removing the water 102 from the working fluid such that the adsorbed water is collected within the second set of mol sieve vessels 120a, 120b.

The mol sieve beds 112 may include 3A mol sieve beds, 4A mol sieve beds, and/or 5A mol sieve beds. The 3A-5A mol sieve beds are suited for adsorbing water 102 from a working fluid while minimizing adsorption of heavy hydrocarbons 103.

The second set of mol sieve vessels 120 are configured to remove water 102 from a working fluid, such as regeneration stream 106 or a portion thereof. In one or more embodiments, the mol sieve beds 112 adsorb the water 102 and the water 102 is retained (e.g. collected) in the second set of mol sieve vessels 120. The second set of mol sieve vessels 120 may be smaller (and/or have a less number of mol sieve beds 112) than the first set of mol sieve vessels 110. In one or more embodiments, the second set of mol sieve vessels 120 are about 5% to about 30% of the size of the first set of mol sieve vessels 110.

After some time, the mol sieve beds 112 within the each of the second set of mol sieve vessels 120a and/or 120b will adsorb an amount of water 102 such that the mol sieve beds 112 are prevented from sufficiently adsorbing additional water 102 from the working fluid passing (e.g. flowing) through each of the second set of mol sieve vessels 120a and/or 120b. The water 102 previously adsorbed (e.g. collected within each of the second set of mol sieve vessels 120a and/or 120b) can then be removed from each of the second set of mol sieve vessels, 120a and/or 120b to regenerate the mol sieve beds 112. The water 102 can be removed by heating the mol sieve beds 112 and/or flowing at least a portion of the working fluid, such as the regeneration gas stream 106, through the mol sieve beds 112 and each of the second set of mol sieve vessels 120a and/or 120b in a direction typically opposite from flow during adsorption.

Accordingly, each of the second set of mol sieve vessels 120a or 120b may either be in adsorption or regeneration. When in adsorption, the mol sieve beds 112 are used to adsorb water 102 thus removing the water 102 from the working fluid passing through the mol sieve vessels 120a or 120b. When in regeneration, a regeneration gas stream, such as regeneration gas stream 106, flowing through the mol sieve vessels 120a and/or 120b regenerates the mol sieve beds 112. The regeneration gas flowing through the mol sieve vessels 120a and/or 120b removes the water 102 previously adsorbed by the mol sieve beds 112 and collected in the mol sieve vessels 120a and/or 120b from the mol sieve vessels 120a and/or 120b. Regeneration may be used to regenerate the mol sieve beds 112 when the mol sieve beds 112 have adsorbed an amount of water 102 such that the mol sieve beds 112 are prevented from properly adsorbing more water 102 from the regeneration gas stream. Each of the second set of mol sieve vessels 120a and/or 120b may be cycled between adsorption and regeneration. In one or more embodiments, switching between adsorption and regeneration requires switching of flow directions through the mol sieve vessels 120a or 120b. Switching flow direction may be accomplished by, for instance, opening and closing of internal or external valves (such as valves 105).

FIG. 1 illustrates an example in which the mol sieve vessels 110a, 120b are in adsorption and the mol sieve vessels 110b, 120a are in regeneration by the notation “A” for adsorption and “R” for regeneration. In one or more embodiments, any of the mol sieve vessels 110a, 110b, 120a, 120b may be in adsorption or regeneration.

The mol sieve system 100 also includes a compressor 130, a regeneration gas heater 140, a regeneration gas cooler 150, a first separation device 160 (e.g. a regeneration gas scrubber, hereinafter referred to as “regeneration gas scrubber 160”), an optional economizing cross exchanger 170, a chiller 180, a second separation device 190 (e.g. a hydrocarbon scrubber, hereinafter referred to as “hydrocarbon scrubber 190”), and a number of valves 105.

The compressor 130 compresses a dry treated working fluid downstream of a vessel (110a or 110b) to increase the pressure of the working fluid. In one or more embodiments, the compressor 130 is used to overcome frictional pressure drop in the mol sieve system 100. The regeneration heater 140 is configured to heat a working fluid passing through the regeneration heater 140. The regeneration gas cooler 150 is configured to cool a working fluid passing through the regeneration gas cooler 150. The regeneration gas scrubber 160 is configured to separate and remove water 102 and/or heavy hydrocarbons 103 from a working fluid passing through the regeneration gas scrubber 160. The economizing cross exchanger 170 acts as a heat exchanger to cool one working fluid passing through the economizing cross exchanger 170 and heat another working fluid passing through the economizing cross exchanger 170. The chiller 180 is configured to cool a working fluid passing through the chiller 180. The hydrocarbon scrubber 190 is configured to separate and remove heavy hydrocarbons 103 from a working fluid passing through the hydrocarbon scrubber 190. That is, the hydrocarbon scrubber 190 is configured to separate out heavy hydrocarbons 103 from the working fluid passing through the heavy hydrocarbon scrubber 190.

A series of valves 105 may define a number of possible flow paths through the system 100. Each valve 105 may be open or closed to alter the flow path of the mol sieve system 100. As a non-limiting example, when the valves 105A are open and the valves 105B are closed, the inlet gas stream 101 flows through valves 105A and is prevented from flowing through valves 105B. For the sake of brevity, the exemplary mode of operation described below is in such a configuration. That is, valves 105A are open and valves 105B are closed. However, it should be understood that any combination of the valves 105 may be open or closed to create any number of flow paths.

According to one mode of operation, the flow of the inlet gas stream 101 flows through the mol sieve system 100 with valves 105A open and valves 105B closed and with mol sieve vessels 110a and 120b in adsorption and mol sieve vessels 110b and 120a in regeneration.

Inlet gas stream 101 is flowed (e.g. compressed) into the mol sieve system 100 at location 1. In one or more embodiments, the inlet gas stream 101 may be within a temperature range of about 40 degrees Fahrenheit (°F.) to about 140° F. and about 100 pounds per square inch gauge (psig) to about 1500 psig, such as about 100° F. and about 700 psig. At location 2, the inlet gas stream 101 enters the first mol sieve vessel 110a. The first mol sieve vessel 110a is in adsorption. From location 2 to location 3, the mol sieve beds 111 in the first mol sieve vessel 110a adsorb water 102 and/or heavy hydrocarbons 103 thus removing the water 102 and heavy hydrocarbons 103 from the inlet gas stream 101. The adsorbed water 102 and/or heavy hydrocarbons 103 are retained (e.g. collected) in the first mol sieve vessel 110a. At location 3, the inlet gas stream 101 leaves the first mol sieve vessel 110a with a reduced amount of heavy hydrocarbons 103 and a reduced amount of water 102. In one or more embodiments, the quantity of heavy hydrocarbons 103 removed by first mol sieve vessel 110a is sufficient so that any of the heavy hydrocarbons 103 remaining in the inlet gas stream 101 do not solidify at the cryogenic conditions of the downstream equipment. In one or more embodiments, the majority of the heavy hydrocarbons (e.g. at least 50% or more) are removed from the inlet gas stream 101 by the first mol sieve vessel 110a. In one or more embodiments, the inlet gas stream 101 may have a composition of about 0.1 parts per million (ppm) water 102 at location 3.

At location 4, the inlet gas stream 101 is split into dry gas stream 104 and regeneration gas stream 106. Dry gas stream 104 exits the mol sieve system 100 (e.g. exits at location 5A). In one or more embodiments, the dry gas stream 104 exits the mol sieve system 100 at about 110° F. and about 680 psig. At location 5, regeneration gas stream 106 is further cycled through the mol sieve system 100. In one or more embodiments, regeneration gas stream 106 is about 5% to about 30% of the inlet gas stream 101. In one or more embodiments, regeneration gas stream 106 is about 10% of the inlet gas stream 101.

Regeneration gas stream 106 enters the compressor 130 at location 5. From location 5 to location 6, the regeneration gas stream 106 is compressed. The compressor 130 compresses the regeneration gas stream 106 to overcome frictional pressure drop through the remainder of the mol sieve system 100 (described below) so that the regeneration gas stream 106 can rejoin the inlet gas stream 101 (e.g. at location 27). In one or more embodiments, the compressor 130 increases the pressure of regeneration gas stream 106 by about 30-40 psig, thereby increasing the pressure of the regeneration gas stream 106 to about 730 psig. In one or more embodiments, the regeneration gas stream 106 at location 6 is at about 730 psig and about 125° F.

At location 7, the regeneration gas stream 106 enters the regeneration gas heater 140. From location 7 to location 8, the regeneration gas stream 106 is heated by the regeneration gas heater 140. In one or more embodiments, the regeneration gas stream 106 is heated to between about 450° F. and about 575° F., such as about 550° F. In one or more embodiments, the regeneration gas stream 106 at location 8 is at about 725 psig and about 550° F.

At location 9, the regeneration gas stream 106 enters the second mol sieve vessel 110b. The second mol sieve vessel 110b is in regeneration. From location 9 to location 10, the regeneration gas stream 106 removes water 102 and heavy hydrocarbons 103 from the second mol sieve vessel 110b. The water 102 and heavy hydrocarbons 103 removed from the second mol sieve vessel 110b were previously adsorbed and removed from a working fluid, such as inlet gas stream 101 or a portion thereof, that passed through the second mol sieve vessel 110b when the second mol sieve vessel 110b was in adsorption.

At location 10, the regeneration gas stream 106 leaves the second mol sieve vessel 110b and includes the water 102 and heavy hydrocarbons 103 from the second mol sieve vessel 110b. In one or more embodiments, the regeneration gas stream 106 including the water 102 and heavy hydrocarbons 103 is at about 540° F. and about 720 psig at location 10.

At location 11, the regeneration gas stream 106 enters the third mol sieve vessel 120a. The third mol sieve vessel 120a is in regeneration. From location 11 to location 12, the regeneration gas stream 106 removes water 102 from the third mol sieve vessel 120a. The water 102 removed from the third mol sieve vessel 120a was previously adsorbed and removed from a working fluid, such as regeneration gas 106 or a portion thereof, that passed through the third mol sieve vessel 120a when the third mol sieve vessel 120a was in adsorption. In one or more embodiments, the regeneration gas stream 106 is at about 530° F. and about 720 psig at location 12.

At location 13, the regeneration gas stream 106 enters the regeneration gas cooler 150. From location 13 to location 14, the regeneration gas cooler 150 cools the regeneration gas stream 106. The regeneration gas cooler 150 cools the regeneration gas stream 106 to a temperature which condenses a large percentage of the water 102, and a small percentage of the heavy hydrocarbons 103, but is above the temperature in which hydrates will form. In one example, hydrates form at a temperature of around 70° F. In one or more embodiments, the regeneration gas cooler 150 cools the regeneration gas stream 106 to about 120° F. In one or more embodiments, the regeneration gas cooler 150 cools the regeneration gas stream 106 by air-cooling, water-cooling, or cooling by another suitable medium. In one or more embodiments, the regeneration gas stream 106 is at about 120° F. and about 715 psig at location 14.

At location 15, the regeneration gas stream 106 enters into the regeneration gas scrubber 160. From location 15 to location 16, the regeneration gas scrubber 160 separates the water 102 in the regeneration gas stream 106 from the regeneration gas stream 106. In one or more embodiments, the water 102 is separated by condensation due to the cooling from the regeneration gas cooler 150. The water 102 that is separated out of the regeneration gas stream 106 by the regeneration gas scrubber 160 may exit the mol sieve system 100 (e.g. at location 16A) and may be disposed of or reused in another process, such as cooling.

At location 17, the regeneration gas stream 106 enters into the fourth mol sieve vessel 120b. The fourth mol sieve vessel 120b is in adsorption. From location 17 to location 18, the mol sieve beds 112 in the fourth mol sieve vessel 120b adsorb water 102 thus removing the water 102 from the regeneration gas stream 106. The adsorbed water is retained (e.g. collected) in the fourth mol sieve vessel 120b. From location 17 to location 18, heavy hydrocarbon removal is minimized. At location 17, the regeneration gas stream 106 leaves the fourth mol sieve vessel 120b with a reduced amount of water 102. The water 102 is removed to prevent hydrates from forming in subsequent processes in the mol sieve system 100. In one or more embodiments, the regeneration gas stream 106 is at about 120° F. and 712 psig with a reduced amount of water at location 18.

From location 19 to location 20 to location 21 and to location 22, the regeneration gas stream 106 is cooled to a desired temperature in order to condense heavy hydrocarbons 103 and reduce heavy hydrocarbon concentration below the freezing point in the downstream process. The chiller 180 and, optionally, the economizing cross exchanger 170 is disposed between locations 19 and 22. The regeneration gas stream 106 flows through the economizing cross exchanger 170 (if included in the mol sieve system 100) and then flows through the chiller 180 to cool the regeneration gas stream 106 below a desired temperature. In one or more embodiments, the desired temperature is a temperature at which at least a portion of the heavy hydrocarbons 103 are condensed and thus can be removed by the hydrocarbon scrubber 190. The portion of the heavy hydrocarbons 103 that are condensed and removed by the hydrocarbon scrubber 190 is sufficient so that any cryogenic processes downstream do not solidify any remaining heavy hydrocarbons such as in the dry gas stream 104 leaving the mole sieve beds 111 at location 5A. In one or more embodiments, the regeneration gas stream 106 is at about 0° F. to about 70° F. at location 21. In one or more embodiments, the regeneration gas stream 106 is at about 0° F. and about 703 psig at location 22.

At location 23, the regeneration gas stream 106 enters the hydrocarbon scrubber 190. From location 23 to location 24, the hydrocarbon scrubber 190 separates at least a portion of the heavy hydrocarbons 103 from the regeneration gas stream 106. The regeneration gas stream 106 leaves the hydrocarbon scrubber 190 with a reduced amount of heavy hydrocarbons 103 at location 24. The separated out heavy hydrocarbons 103 may exit the mol sieve system 100 (e.g. at location 24A) and may be directed to storage, fuel, flare, or another location or used for another purpose.

At location 25, the regeneration gas stream 106 may reenter the economizing cross exchanger 170 (if included in the mol sieve system 100) for reheating from location 25 to location 26. The reheated regeneration gas stream 106 then rejoins the inlet gas stream 101 at location 27.

The process may be repeated until the mol sieve beds 111 in the first mol sieve vessel 110a adsorb an amount of water 102 and/or heavy hydrocarbons 103 such that the mol sieve beds 111 are not efficiently removing any further water 102 and/or hydrocarbons 103 from the inlet gas stream 101. When the first mol sieve beds 111 in first mol sieve vessel 110a adsorb such an amount of water 102 and/or heavy hydrocarbons 103, the first mol sieve vessel 110a can be switched to regeneration, such as by opening and/or closing of valves 105A, 105B. Similarly, the process may be repeated until the mol sieve beds 112 in the fourth mol sieve vessel 120b adsorb an amount of water 102 such that the mol sieve beds 112 are not efficiently removing any further water 102 from the regeneration gas stream 106. When the mol sieve beds 112 in the fourth mol sieve vessel 120b adsorb such an amount of water 102, the fourth mol sieve vessel 120b can be switched to regeneration. In one or more embodiments, the first mol sieve vessel 110a and fourth mol sieve vessel 120b may be switched between adsorption and regeneration independently or simultaneously, such as by opening or closing any of valves 105A or valves 105B.

Similarly, the process may be repeated until the mol sieve beds 111 in the second mol sieve vessel 110b are sufficiently regenerated such that they can efficiently remove water 102 and/or heavy hydrocarbons 103 from the inlet gas stream 101. When the mol sieve beds 111 of the second mol sieve vessel 110b are sufficiently regenerated, the second mol sieve vessel 110b may be switched to adsorption, such as by opening and/or closing of valves 105A, 105B. Similarly, the process may be repeated until the mol sieve beds 112 in the third mol sieve vessel 120b are sufficiently regenerated such that they can efficiently remove water 102 from the regeneration gas stream 106. When the mol sieve beds 112 of the third mol sieve vessel 120a are sufficiently regenerated, the third mol sieve vessel 120a may be switched to adsorption, such as by opening and/or closing of valves 105A, 105B. In one or more embodiments, the second mol sieve vessel 110b and the third mol sieve vessel 120a may be switched between adsorption and regeneration independently or simultaneously, such as by opening or closing any of valves 105A or valves105B.

As stated previously, the orientation of valves 105 may be swapped. As a non-limiting example, valves 105B may be open and valves 105A may be closed. In such a configuration, the inlet gas stream 101 flows through the second mol sieve vessel 110b in adsorption, is split into the dry gas stream 104 and regeneration gas stream 106, the regeneration gas stream 106 flows through the compressor 130, the regeneration gas heater 140, the first mol sieve vessel 110a in regeneration, the fourth mol sieve vessel 120b in regeneration, the regeneration gas cooler 150, the regeneration gas scrubber 160, the third mol sieve vessel 120a in adsorption, optionally the economizing cross exchanger 170, the chiller 180, the hydrocarbon scrubber 190, optionally the economizing cross exchanger 170, and rejoins the inlet gas stream 101.

As another non-limiting example, any of valves 105A or 105B may be opened or closed to swap any of mol sieve vessels 110a, 110b, 120a, 120b between regeneration and adsorption.

Any one or more components of the mol sieve system 100 may be integrally formed together, directly coupled together, and/or indirectly coupled together and are not limited to the specific arrangement of components illustrated in FIG. 1. Any of the one or more embodiments of the mol sieve system 100 may be combined, in whole or in part, with any of the other one or more embodiments of the mol sieve system 100.

It will be appreciated by those skilled in the art that the preceding embodiments are exemplary and not limiting. It is intended that all modifications, permutations, enhancements, equivalents, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the scope of the disclosure. It is therefore intended that the following appended claims may include all such modifications, permutations, enhancements, equivalents, and improvements. The disclosure also contemplates that one or more aspects of the embodiments described herein may be substituted in for one or more of the other aspects described.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.