Hydrocarbon recovery unit with recirculation loop for sorbent bed regeneration

Abstract

Disclosed in certain embodiments are methods for heavy hydrocarbon removal, the method implementing introducing a sorbent into a regeneration loop of a regeneration gas stream; and systems for implementing the method.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 127,876, filed December 18, 2020, the disclosure of which is hereby incorporated herein by reference in its entirety. Background Technology

[0003] Hydrocarbon recovery units (HRUs) typically utilize one or more adsorbent beds during hydrocarbon adsorption, while these beds are simultaneously regenerated via a regeneration loop. The regeneration loop employs a heating step followed by a cooling step using either a gas feed stream or a treated gas stream as the regeneration gas. Contaminants are then removed from the regeneration gas in liquid form via a condenser during cooling, while the separated regeneration gas is recycled to the feed side of one or more adsorbent beds and mixed with the feed gas. The regeneration process can be tailored to specific adsorbent masses and cycle times, allowing for the preferential removal of one or more contaminants. However, if certain contaminants, such as thiols, are not adequately removed through separation, excess contaminants are reintroduced into the feed gas, resulting in higher concentrations of contaminants on the feed side of one or more adsorbent beds. Summary of the Invention

[0004] The following summary presents a simplified overview of various aspects of this disclosure to provide a basic understanding of these aspects. This summary is not an exhaustive summary of this disclosure. It is not intended to identify key or essential elements of this disclosure, nor is it intended to depict any scope of any particular embodiment of this disclosure or any scope of the claims. The sole purpose of the summary is to present some concepts of this disclosure in a simplified form as a prelude to the more detailed description that follows.

[0005] In one aspect of this disclosure, the method includes: introducing a gas feed stream comprising C5+ hydrocarbons or organosulfur species into a first adsorbent bed to generate a treated gas stream; regenerating a second adsorbent bed with a portion of the treated gas stream to generate a regenerated gas stream; introducing an adsorbent into the regenerated gas stream to remove a portion of the C5+ hydrocarbons or organosulfur species; subsequently removing the portion of the C5+ hydrocarbons or organosulfur species from the regenerated gas stream; and subsequently mixing the regenerated gas stream with the gas feed stream.

[0006] In at least one embodiment, the C5+ hydrocarbon or organosulfur species includes thiols.

[0007] In at least one embodiment, the method further includes cooling the regenerated gas stream to below 50°C after the adsorbent is introduced.

[0008] In at least one embodiment, the adsorbent comprises a C7+ hydrocarbon. In at least one embodiment, the C7+ hydrocarbon corresponds to the C7+ hydrocarbon removed from the regeneration stream.

[0009] In at least one embodiment, the adsorbent comprises one or more of polyethylene glycol, alkanes, or aromatic compounds.

[0010] In at least one embodiment, the subsequent removal of the portion of the C5+ hydrocarbons or organosulfur species includes separating the adsorbent and liquid water from the regeneration gas stream using three-phase separation. In at least one embodiment, the separated adsorbent includes the portion of the C5+ hydrocarbons or organosulfur species. In at least one embodiment, the method further includes: flash evaporating the separated adsorbent to remove the portion of the C5+ hydrocarbons or organosulfur species; and subsequently reintroducing the adsorbent into the regeneration gas stream.

[0011] In at least one embodiment, one or more of the first adsorbent bed or the second adsorbent bed include amorphous silica adsorbent and / or amorphous silica-alumina adsorbent, high-silica zeolite, zeolite X, zeolite 5A, or combinations thereof.

[0012] In at least one embodiment, one or more of the first adsorbent bed or the second adsorbent bed include zeolites, said zeolites including zeolite 3A, zeolite 4A, zeolite 5A, or zeolite 13X, or combinations thereof. In at least one embodiment, the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr, or Ba.

[0013] In another aspect of this disclosure, the adsorption system includes: a feed gas inlet; a first adsorbent bed fluidly coupled to the feed gas inlet to receive a gas feed stream comprising C5+ hydrocarbons or organosulfur species; and a regeneration circuit fluidly coupled to the first adsorbent bed. In at least one embodiment, the regeneration circuit includes: a second adsorbent bed configured to receive a treated gas stream from the first adsorbent bed; an adsorbent flow path configured to introduce adsorbent into a regeneration gas stream from the second adsorbent bed to remove at least a portion of the C5+ or organosulfur species from the regeneration gas stream; and a separator fluidly coupled to the first adsorbent bed, configured to separate the adsorbent from the regeneration gas stream before mixing with the gas feed stream.

[0014] In at least one embodiment, the regeneration loop includes a cooler located downstream of the second adsorbent bed and upstream of the separator, the cooler being configured to cool the regeneration gas and the adsorbent.

[0015] In at least one embodiment, the separator is a three-phase separator configured to separate the adsorbent and liquid water from the regenerated gas stream.

[0016] In at least one embodiment, the adsorption system further includes a heater located downstream of the separator to heat the adsorbent and remove the adsorbed C5+ hydrocarbons or organic sulfur species.

[0017] In at least one embodiment, one or more of the first adsorbent bed or the second adsorbent bed include amorphous silica adsorbent and / or amorphous silica-alumina adsorbent.

[0018] In at least one embodiment, one or more of the first adsorbent bed or the second adsorbent bed include amorphous silica adsorbent and / or amorphous silica-alumina adsorbent, high-silica zeolite, zeolite X, zeolite 5A, or combinations thereof.

[0019] In at least one embodiment, one or more of the first adsorbent bed or the second adsorbent bed include zeolites, said zeolites including zeolite 3A, zeolite 4A, zeolite 5A, or zeolite 13X, or combinations thereof. In at least one embodiment, the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr, or Ba.

[0020] In another aspect of this disclosure, the natural gas purification system includes any of the aforementioned adsorption systems. Attached Figure Description

[0021] The disclosure is illustrated by way of example and not limitation in the accompanying drawings, in which:

[0022] Figure 1 An adsorbent bed used according to at least one embodiment of the present disclosure is shown;

[0023] Figure 2A A schematic diagram of an illustrative system for hydrocarbon removal according to a first embodiment of the present disclosure is shown;

[0024] Figure 2B A schematic diagram of an illustrative system for hydrocarbon removal according to a second embodiment of the present disclosure is shown;

[0025] Figure 2C A schematic diagram of an illustrative system for hydrocarbon removal according to a third embodiment of the present disclosure is shown;

[0026] Figure 3 A regeneration process in a system for hydrocarbon removal according to at least one embodiment is shown; and

[0027] Figure 4 A schematic diagram of a system for hydrocarbon removal, based on a comparative example, is shown. Detailed Implementation

[0028] This disclosure generally relates to systems and methods for the removal of heavy hydrocarbons. Specifically, some embodiments include a regeneration loop that introduces adsorbent into a regeneration gas stream to adsorb, for example, C5+ hydrocarbons (e.g., n-heptane) and / or thiols. When reintroduced into the adsorbent bed along with the gas feed stream during the adsorption cycle, the embodiments described herein advantageously reduce the accumulation of heavy hydrocarbons and thiols in the gas stream from the regeneration loop.

[0029] The adsorption process of this disclosure for removing mercaptans, heavy hydrocarbons (e.g., C5+ or C6+ components) and / or water from a gas feed stream (e.g., a natural gas feed stream) can be achieved by temperature-switched adsorption (TSA). TSA processes are generally known in the art for various types of adsorption separations. Typically, a TSA process utilizes process steps of adsorption at a low temperature, regeneration with a hot purge gas at a high temperature, and subsequent cooling to the adsorption temperature. TSA processes are commonly used for drying gases and liquids, and for purification to remove trace impurities. TSA processes are typically employed when the components to be adsorbed are strongly adsorbed onto the adsorbent, thus requiring heat for regeneration. A typical TSA process comprises adsorption cycles and regeneration (desorption) cycles, each cycle potentially containing multiple adsorption and regeneration steps, as well as cooling and heating steps. The regeneration temperature is higher than the adsorption temperature to achieve desorption of water, mercaptans, and heavy hydrocarbons.

[0030] In the regeneration step, a portion of one of the gas streams (e.g., a natural gas stream), the product effluent from the adsorption unit, or the waste stream from a downstream process may be heated, and the heated stream is circulated through the adsorbent to desorb the adsorbed components. In some embodiments, it is advantageous to use a thermal purge stream comprising a heated raw natural gas stream to regenerate the adsorbent.

[0031] In some embodiments, the pressure used during the adsorption and regeneration steps is typically increased to 700 to 1500 psig. Generally, heavy hydrocarbon adsorption is carried out at pressures close to the feed stream pressure, and the regeneration step can be carried out at approximately the adsorption pressure or at reduced pressure. Regeneration can advantageously be carried out at approximately the adsorption pressure when a portion of the adsorption effluent is used as purge gas, particularly when, for example, the waste stream or purge stream is reintroduced into the original natural gas stream.

[0032] As used herein, “thiol” refers to an organic sulfur-containing compound, including but not limited to methyl mercaptan (C1-RSH), ethyl mercaptan (C2-RSH), propyl mercaptan (C3-RSH), butyl mercaptan (C4-RSH), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS).

[0033] Although embodiments of this disclosure are described in relation to natural gas purification processes, those skilled in the art will understand that the embodiments herein can be used or applied to other types of industrial applications requiring hydrocarbon removal.

[0034] Figure 1 An adsorbent bed 100 according to a first embodiment of the present disclosure is shown, which can be adapted for use in a TSA process. The adsorbent bed 100 comprises adsorbent layers 110, 120, and 130, each contained within a container 102. These three adsorbents are merely illustrative, and it should be understood that any suitable number of different adsorbent layers (e.g., single layer, double layer, etc.) can be used. The flow direction indicates the flow of the gas feed stream through the inlet of container 102, through adsorbent layer 110, through adsorbent layer 120, and then through adsorbent layer 130 before reaching the outlet of container 102. Based on this flow direction, adsorbent layer 120 is referred to as being downstream of adsorbent layer 110. Similarly, adsorbent 130 is referred to as being downstream of adsorbent layer 120. In some embodiments, each adsorbent layer may comprise its respective adsorbent in the form of adsorbent beads with a diameter, for example, between about 1 mm and about 5 mm. The relative dimensions of the adsorbent layers are not necessarily drawn to scale, although in some embodiments, the weight percentage (wt.%) of adsorbent layer 110 relative to the total weight of adsorbent bed 100 (i.e., the total weight of adsorbent layer 110, adsorbent layer 120, and adsorbent layer 130) may be greater than 50 wt.%, greater than 60 wt.%, greater than 70 wt.%, greater than 80 wt.%, or greater than 90 wt.%.

[0035] In some embodiments, one or more of adsorbent layers 110, 120, or 130 comprise an adsorbent preferably composed of C5+ or C6+ hydrocarbons. In some embodiments, one or more of adsorbent layers 110, 120, or 130 comprise an adsorbent preferably composed of thiols. As used herein, the terms “preferentially selective for” or “selective for” indicate that the adsorbent adsorbs a particular compound at a greater equilibrium load than methane, further described by the following formula: Selectivity = (load C6+ / concentration C6+) / (load C1 / concentration C1), where C1 is methane, and where the load is defined as the number of moles of the adsorbed component / the number of grams of adsorbent. In some embodiments, the C5+ or C6+ compound may include one or more of pentane, hexane, benzene, heptane, octane, nonane, toluene, ethylbenzene, xylene, or neopentane.

[0036] In some embodiments, one or more of adsorbent layers 110, 120, or 130 comprises one or more of amorphous silica adsorbents, amorphous silica-alumina adsorbents, or high-silica zeolite adsorbents. In some embodiments, one or more of adsorbent layers 110, 120, or 130 comprises amorphous silica adsorbents and / or amorphous silica-alumina adsorbents. The amorphous silica adsorbents and amorphous silica-alumina adsorbents may be at least partially crystalline. In some embodiments, the amorphous silica adsorbents or amorphous silica-alumina adsorbents may be at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or 100% amorphous. In some embodiments, the amorphous silica adsorbents or amorphous silica-alumina adsorbents may additionally contain other components, such as charge-balanced cations. In some embodiments, one or more of the adsorbent layers 110, 120, or 130 comprise a high-silica zeolite adsorbent, such as β-zeolite, ZSM-5, Y-zeolite, or combinations thereof. As used herein, “high-silica zeolite” means a material with a silica:alumina ratio of at least 5, at least 10, at least 20, at least 30, at least 50, at least 100, at least 150, at least 200, at least 250, at least 300, at least 350, at least 400, at least 450, or at least 500 molars. In some embodiments, the silica:alumina ratio is in the range of 20 to 500.

[0037] In some embodiments, one or more of adsorbent layers 110, 120, or 130 include one or more of zeolite A, zeolite X (e.g., zeolite 13X, which is zeolite X that has been exchanged with sodium ions), or zeolite Y. In some embodiments, one or more of adsorbent layers 110, 120, or 130 include one or more of zeolite 3A, zeolite 4A, zeolite 5A, or zeolite X. In some embodiments, the zeolite is exchanged with any element in columns I and II of the periodic table (such as Li, Na, K, Mg, Ca, Sr, or Ba). In some embodiments, one or more of adsorbent layers 110, 120, or 130 include one or more of zeolite 5A or zeolite X. In some embodiments, the zeolite is exchanged with any element in columns I and II of the periodic table (such as Li, Na, K, Mg, Ca, Sr, or Ba). In some embodiments, adsorbent layer 130 includes zeolite X, and zeolite X is zeolite 13X (i.e., zeolite X that has been exchanged with sodium ions).

[0038] An exemplary adsorbent for one or more of adsorbent layers 110, 120, or 130 may contain Durasorb. TM HD, Durasorb TM BTX, Durasorb TMHC, Durasorb TM AR or Durasorb TM One or more of HR4 (available from BASF).

[0039] Figure 2A A schematic diagram of an illustrative system 200 for hydrocarbon removal according to embodiments of the present disclosure is shown. System 200 includes a feed gas source 212 that guides a feed gas (e.g., natural gas) along stream 201. For example, during an adsorption cycle in a TSA process, stream 202 is guided to an adsorbent bed 220. In some embodiments, the gas composition of stream 202 corresponds to the gas composition of stream 201. In some embodiments, the gas composition of stream 202 corresponds to a mixture of streams 201 and 206, which is the regeneration gas stream described in more detail below.

[0040] In some embodiments, the stream 203 exiting the adsorbent bed passes through a filter 226 (e.g., a dust filter) and splits into two paths: a first path that collects the treated gas 213 and a second path that uses a portion of the treated gas 213 as part of a regeneration loop. The second path may be used to heat the treated gas via a heater 225 to promote desorption in the adsorbent bed 221. The regeneration gas stream 204 exiting the adsorbent bed 221 is then directed along stream 205 to a cooler 223 to promote the condensation of water and C5+ hydrocarbons.

[0041] In some embodiments, an adsorbent (e.g., a liquid comprising C7+ hydrocarbons, polyethylene glycol, etc.) from stream 209 (which may be a liquid delivery line) is injected into regeneration gas stream 204 via syringe 230. The adsorbent can be pumped from adsorbent source 214 along stream 210 via pump 231. In some embodiments, syringe 230 includes an injection point followed by a static mixer (which may be located directly downstream of the injection point and before cooler 223). The static mixer provides a method for mixing gas and liquid. A suitable static mixer may contain, for example, an SMV. TM Static mixer (available from SULZER).

[0042] In some embodiments, separator 224 is a three-phase separator adapted to separate the components of stream 205 into a gas phase (stream 206), a liquid aqueous phase (stream 207), and a liquid adsorbent phase. The liquid adsorbent phase passes through heater 232 before reaching separator 234. Heater 232 and separator 234 can be used to flash-evaporate C5+ and organic sulfur species (e.g., thiols) contained in the adsorbent to separate the adsorbent (which is removed by gas treatment 216) from the gaseous stream 208 of C5+ and organic sulfur species. After passing through cooler 233, the separated adsorbent can be recycled as part of stream 209 by mixing with stream 210. In some embodiments, stream 211 is used to remove adsorbent (e.g., adsorbent purging 215).

[0043] The water removed by separator 224 is conveyed along stream 207 for treatment (e.g., water treatment 217), while the separated regenerated gas stream 206 passes through compressor 222 before being reintroduced into adsorbent bed 220 via stream 202.

[0044] Figure 2B A schematic diagram of an illustrative system 250 for hydrocarbon removal according to an embodiment of the present disclosure is shown, which is a variant of system 200. The recirculation loop of system 250 differs from that of system 200 in that, after the adsorbent separated by separator 224 is sent to separator 234, the gas phase of stream 218 is cooled by cooler 236 before being mixed with regeneration gas stream 206. The liquid phase of separator 234 is then cooled by cooler 233 and sent to separator 235 to separate C5+ and organic sulfur species from the adsorbent.

[0045] Figure 2C A schematic diagram of an illustrative system 260 for hydrocarbon removal according to an embodiment of the present disclosure is shown, which is a further variation of system 200. The recirculation loop of system 260 differs from that of system 200 in that, after the adsorbent separated by separator 224 is sent to separator 234, the gas phase of stream 218 is compressed by compressor 237 and cooled by cooler 236 before reaching separator 235. In some embodiments, separator 235 removes thiols (e.g., thiols treatment 219), and the gas phase of stream 208 is mixed with regeneration gas stream 206.

[0046] Figure 3A regeneration method 300 in an HRU system according to at least one embodiment is illustrated. At block 302, a gas feed stream is introduced into a first adsorbent bed (e.g., adsorbent bed 100 or 220) to generate a treated gas stream. In some embodiments, the adsorbent bed comprises one or more adsorbent layers, such as one or more of adsorbent layers 110, 120, or 130. In some embodiments, the first adsorbent bed comprises amorphous silica adsorbent and / or amorphous silica-alumina adsorbent, high-silica zeolite, zeolite X, zeolite 5A, or combinations thereof. In some embodiments, the first adsorbent bed comprises zeolite, the zeolite comprising zeolite 3A, zeolite 4A, zeolite 5A, or zeolite 13X, or combinations thereof. In some embodiments, the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr, or Ba.

[0047] In some embodiments, the gas feed stream comprises C5+ hydrocarbons or organic sulfur species (e.g., thiols). In some embodiments, the gas feed stream (e.g., stream 201) comprises a natural gas feed stream (e.g., feed gas 212). In some embodiments, the gas feed stream 201 is mixed with a regeneration gas stream (e.g., stream 206) before being introduced into the first adsorbent bed (e.g., as stream 202).

[0048] In some embodiments, the feed stream is introduced into the first adsorbent bed as part of the TSA process. The TSA process may have an adsorption cycle time of less than or equal to about 8 hours, about 7 hours, about 6 hours, about 5 hours, about 4 hours, about 3 hours, about 2 hours, or about 1 hour.

[0049] At frame 304, a second adsorbent bed (e.g., adsorbent bed 100 or 221) is regenerated with a portion of the treated gas stream (e.g., stream 203) to produce a regenerated gas stream (e.g., stream 204). In some embodiments, the adsorbent bed comprises one or more adsorbent layers, such as one or more of adsorbent layers 110, 120, or 130. In some embodiments, the second adsorbent bed comprises amorphous silica adsorbent and / or amorphous silica-alumina adsorbent, high-silica zeolite, zeolite X, zeolite 5A, or combinations thereof. In some embodiments, the second adsorbent bed comprises zeolite, including zeolite 3A, zeolite 4A, zeolite 5A, or zeolite 13X, or combinations thereof. In some embodiments, the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr, or Ba.

[0050] At box 306, an adsorbent is introduced (e.g., via syringe 230) into the regeneration gas stream. In some embodiments, the adsorbent is used to remove at least a portion of C5+ hydrocarbons or organic sulfur species from the regeneration gas stream. In some embodiments, the adsorbent is liquid and comprises C7+ hydrocarbons (e.g., C7+ hydrocarbons removed from the regeneration gas stream). In some embodiments, the adsorbent comprises one or more of polyethylene glycol, alkanes (e.g., C8+ hydrocarbons), aromatic compounds (e.g., C7+ hydrocarbons), or other adsorbents that do not substantially accumulate in the recirculation loop. In some embodiments, after the adsorbent is introduced at box 306, the regeneration gas stream is cooled (e.g., via cooler 223) to below 50°C.

[0051] At box 308, C5+ hydrocarbons or organosulfur species are subsequently removed from the regeneration gas stream (e.g., via separator 224). In some embodiments, the removal of C5+ hydrocarbons or organosulfur species is achieved by separating the adsorbent and liquid water from the regeneration gas stream using three-phase separation. In some embodiments, the adsorbent comprises a portion of the C5+ hydrocarbons or organosulfur species. In some embodiments, method 300 further comprises flash evaporation of the separated adsorbent (e.g., via heater 232 and separator 234) to remove a portion of the C5+ hydrocarbons or organosulfur species contained in the adsorbent. In some embodiments, the adsorbent is then reintroduced (via stream 209) into the regeneration gas stream.

[0052] At frame 310, the regenerated gas stream (e.g., stream 206) is then mixed with the gas feed stream 201 and reintroduced into the first adsorbent bed.

[0053] Illustrative Examples

[0054] The following examples, based on simulations, are presented to aid in understanding this disclosure, and should not be construed as specifically limiting the embodiments described and claimed herein. Any variations, changes in formulations, or minor alterations in experimental design of the disclosed embodiments that would be understood by one of those skilled in the art and include substitutions for all now-known or hereafter developed equivalents are considered to fall within the scope of the embodiments incorporated herein.

[0055] Example 1

[0056] When describing this instance, refer to Figure 2ASystem 200 aims to reduce the level of mercaptan in feed gas 212. Feed gas 212, as described in stream 201 of Table 1, is fed into adsorbent bed 220 containing 20,000 kg of adsorbent. The adsorption step is performed for 120 minutes, and after the adsorption step, adsorbent bed 221 is heated, and a portion of the product gas is generated as a stream having an average composition as described in stream 204 of Table 1, which exits adsorbent bed 221 throughout the cycle. This stream is then flashed in a regeneration step with an average composition at a pressure and temperature corresponding to a cooler (e.g., cooler 223). As can be seen from Table 1, stream 208 exiting separator 234 removes most of the methanethiol, resulting in a reduction in the accumulation of methanethiol in the feed to adsorbent bed 220, as shown in the composition in stream 202. This can be achieved by flashing the hydrocarbon liquid exiting separator 224 and recycling liquid stream 209 back to the inlet side of cooler 223. The recirculated heavier thiols or hydrocarbons adsorb lighter thiols, which reduces the concentration returned to the adsorbent bed 220. In some embodiments, the separator 234 can be replaced by a distillation column.

[0057] Table 1: Reference Figure 2A 1 instance of a stream definition

[0058]

[0059]

[0060] Example 2

[0061] When describing this instance, refer again to Figure 2A System 200 aims to reduce the level of n-heptane in feed gas 212. Feed 212, as described in stream 201 of Table 2, is fed into adsorbent bed 220 containing 4,200 kg of adsorbent. The adsorption step is performed for 170 minutes, and after the adsorption step, adsorbent bed 221 is heated, and a portion of the product gas is generated to produce a stream having an average composition as described in stream 204 of Table 2, which exits adsorbent bed 221 throughout the cycle. This stream is then flashed in a regeneration step with an average composition at a pressure and temperature corresponding to a cooler (e.g., cooler 223). As can be seen from Table 2, the gas exiting separator 234 has removed most of the n-heptane, resulting in a reduction in the accumulation of n-heptane in the feed of adsorbent bed 220, as shown in the composition in stream 202. This can be achieved by flashing the hydrocarbon liquid exiting separator 224 and recycling liquid stream 209 back to the inlet side of cooler 223. The heavier hydrocarbons recirculated adsorb the lighter n-heptane, which reduces the concentration returned to the adsorbent bed 220. In some embodiments, the separator 234 can be replaced by a distillation column.

[0062] Additionally, since stream 201 does not contain heavy-end fractions, a separate, small n-C10 stream 210 can be introduced in this case. As can be seen from Table 2, the composition of stream 210 is smaller compared to stream 209. A discharge stream 211 may also exist to allow the removal of heavy hydrocarbons from the recirculation loop; this discharge stream may or may not be necessary if the heavy fractions do not exit via vapor in stream 208.

[0063] Table 2: Reference Figure 2A 2 instances of stream definitions

[0064]

[0065] Comparison Example 1

[0066] Figure 4 A schematic diagram of a system 400 for hydrocarbon removal according to Comparative Examples 1 and 2 is shown. System 400 includes a feed gas source 212 that guides the feed gas along stream 401. For example, during an adsorption cycle in a TSA process, stream 402 is guided to adsorbent bed 420. In some embodiments, the gas composition of stream 402 corresponds to the gas composition of stream 401. In some embodiments, the gas composition of stream 402 corresponds to a mixture of streams 401 and 406, which is a regeneration gas stream. In some embodiments, stream 403 exiting the adsorbent bed passes through filter 426 (e.g., a dust filter) and splits into two paths: a first path that collects treated gas 413 and a second path that uses a portion of the treated gas 413 as part of a regeneration loop. The second path may be used to heat the treated gas via heater 425 to promote desorption in adsorbent bed 421. The regeneration gas stream 404 exiting adsorbent bed 421 is then guided along stream 404 to separator 424 to separate and remove heavy hydrocarbons 407 (e.g., by treatment 417). The separated regenerated gas stream 406 passes through compressor 422 before being mixed with gas stream 401 and reintroduced into adsorbent bed 420.

[0067] When describing this instance, refer to Figure 4System 400 is designed to reduce the level of mercaptan in feed 412. Feed gas 412, as described in stream 401 of Table 3, is fed into adsorbent bed 420 containing 24,000 kg of adsorbent. The adsorption step is performed for 120 minutes, and after the adsorption step, adsorbent bed 421 is heated, producing a portion of the product gas having an average composition as described in stream 404 of Table 3. This stream exits adsorbent bed 421 throughout the cycle. This stream is then flash-evaporated in a regeneration step with an average composition at a pressure and temperature corresponding to a cooler (e.g., cooler 223). As can be seen from Table 3, stream 406 exiting separator 224 does not remove methanethiol to the same extent as in Example 1, which is evidenced by the increased accumulation of methanethiol in the feed to adsorbent bed 420, as shown in the composition of stream 402.

[0068] Table 3: Reference Figure 4 Comparison Example 1 of Stream Definitions

[0069]

[0070] Comparison Example 2

[0071] When describing this instance, refer to Figure 4 System 400 aims to reduce the level of n-heptane in feed 412. Feed gas 412, as described in stream 401 in Table 4, is fed into adsorbent bed 420 containing 4,200 kg of adsorbent. The adsorption step is performed for 170 minutes, and after the adsorption step, adsorbent bed 421 is heated, producing a portion of the product gas with an average composition as described in stream 404, which exits adsorbent bed 421 throughout the cycle. This stream is then flashed in a regeneration step with an average composition at a pressure and temperature corresponding to a cooler (e.g., cooler 223). As can be seen from Table 4, stream 406 exiting separator 424 does not remove n-heptane to the same extent as in Example 2, which is evidenced by the increased accumulation of n-heptane in the feed to adsorbent bed 420, as shown in the composition in stream 402.

[0072] Table 4: Reference Figure 4 Comparison example 2 of stream definitions

[0073]

[0074] The foregoing description has set forth numerous specific details, such as specific materials, dimensions, and process parameters, to provide a thorough understanding of the embodiments of this disclosure. In one or more embodiments, particular features, structures, materials, or properties may be combined in any suitable manner. As used herein, the terms “example” or “exemplary” refer to any aspect or design used as an instance, example, or illustration. Any aspect or design described herein as an “example” or “exemplary” is not necessarily to be construed as superior to or better than other aspects or designs. In fact, the use of the terms “example” or “exemplary” is intended to present concepts in a concrete manner.

[0075] As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise stated or obvious from the context, "X contains A or B" is intended to mean any natural inclusion. That is, if X contains A; X contains B; or X contains both A and B, then "X contains A or B" is satisfied in any of the foregoing cases. Additionally, unless otherwise stated or obvious from the context concerning the singular form, the article "a / an" as used in this application and the appended claims should generally be interpreted as meaning "one or more".

[0076] Throughout this specification, references to "embodiment," "some embodiments," or "one embodiment" mean that at least one embodiment includes a particular feature, structure, or characteristic described in connection with the embodiment. Therefore, the phrases "embodiment," "some embodiments," or "one embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, and such references mean "at least one."

[0077] It should be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the above description. Therefore, the scope of this disclosure should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. A method for removing C5+ hydrocarbons or organic sulfur species from a gas feed stream, comprising: A gas feed stream comprising C5+ hydrocarbons or organic sulfur species is introduced into the first adsorbent bed to produce a treated gas stream. The second adsorbent bed is regenerated using a portion of the treated gas stream to generate a regenerated gas stream; A liquid adsorbent is introduced into the regenerated gas stream to remove a portion of the C5+ hydrocarbons or organic sulfur species. Subsequently, a portion of the C5+ hydrocarbons or organosulfur species are removed from the regenerated gas stream; as well as The regenerated gas stream, from which a portion of the C5+ hydrocarbons or organic sulfur species have been removed, is then mixed with the gas feed stream.

2. The method according to claim 1, wherein the organic sulfur species includes thiols.

3. The method according to claim 1 or claim 2, further comprising cooling the regenerated gas stream to below 50°C after introducing the liquid adsorbent.

4. The method according to claim 1 or 2, wherein the liquid adsorbent comprises a C7+ hydrocarbon.

5. The method of claim 4, wherein the C7+ hydrocarbon corresponds to the C7+ hydrocarbon removed from the regeneration stream.

6. The method according to claim 1 or 2, wherein the liquid adsorbent comprises one or more of polyethylene glycol, alkanes, or aromatic compounds.

7. The method according to claim 1 or 2, wherein subsequent removal of the portion of the C5+ hydrocarbons or organosulfur species comprises separating the liquid adsorbent and liquid water from the regenerated gas stream using three-phase separation, wherein the separated liquid adsorbent comprises the adsorbed portion of the C5+ hydrocarbons or organosulfur species.

8. The method of claim 7, further comprising: The separated liquid adsorbent is flash-evaporated to remove a portion of the C5+ hydrocarbons or organic sulfur species; as well as The liquid adsorbent is then reintroduced into the regenerated gas stream.

9. The method according to claim 1 or 2, wherein one or more of the first adsorbent bed or the second adsorbent bed comprises amorphous silica adsorbent and / or amorphous silica-alumina adsorbent, high-silica zeolite, zeolite X, zeolite 5A or a combination thereof.

10. The method according to claim 1 or 2, wherein one or more of the first adsorbent bed or the second adsorbent bed comprises zeolite, the zeolite comprising zeolite 3A, zeolite 4A, zeolite 5A or zeolite 13X or a combination thereof.

11. The method of claim 9, wherein the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr or Ba.

12. The method of claim 10, wherein the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr or Ba.

13. The method according to claim 1 or 2, wherein the liquid adsorbent comprises polyethylene glycol, or C7+ hydrocarbon and polyethylene glycol.

14. An adsorption system comprising: Feed gas inlet; A first adsorbent bed is fluidly connected to the feed gas inlet to receive a gas feed stream comprising C5+ hydrocarbons or organic sulfur species. as well as A regeneration circuit, which is fluidly connected to the first adsorbent bed, comprises: A second adsorbent bed is configured to receive a processed gas stream from the first adsorbent bed; An adsorbent flow path configured to introduce liquid adsorbent into a regeneration gas stream from the second adsorbent bed to remove at least a portion of the C5+ hydrocarbons or organosulfur species from the regeneration gas stream; and A separator, which is fluidly connected to the first adsorbent bed, is configured to separate the adsorbent from the regeneration gas stream before it is mixed with the gas feed stream.

15. The adsorption system of claim 14, wherein the regeneration loop includes a cooler located downstream of the second adsorbent bed and upstream of the separator, the cooler being configured to cool the regeneration gas and the adsorbent.

16. The adsorption system according to claim 14 or 15, wherein the separator is a three-phase separator configured to separate the adsorbent and liquid water from the regeneration gas stream.

17. The adsorption system according to claim 14 or 15, further comprising a heater located downstream of the separator to heat the adsorbent and remove the adsorbed C5+ hydrocarbons or organosulfur species.

18. The adsorption system according to claim 14 or 15, wherein one or more of the first adsorbent bed or the second adsorbent bed comprises amorphous silica adsorbent and / or amorphous silica-alumina adsorbent.

19. The adsorption system according to claim 14 or 15, wherein one or more of the first adsorbent bed or the second adsorbent bed comprises amorphous silica adsorbent and / or amorphous silica-alumina adsorbent, high-silica zeolite, zeolite X, zeolite 5A or a combination thereof.

20. The adsorption system according to claim 14 or 15, wherein one or more of the first adsorbent bed or the second adsorbent bed comprises zeolite, the zeolite comprising zeolite 3A, zeolite 4A, zeolite 5A or zeolite 13X or a combination thereof.

21. The adsorption system of claim 19, wherein the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr or Ba.

22. The adsorption system of claim 20, wherein the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr or Ba.

23. The adsorption system according to claim 14 or 15, wherein the liquid adsorbent comprises C7+ hydrocarbons and / or polyethylene glycol.

24. A natural gas purification system comprising an adsorption system according to any one of claims 14 to 23.

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