Gas stream composition removal system and method

Abstract

A system for removing a selected component from a gas stream has a heat exchanger including a first cooling passage configured to receive a feed gas stream and provide a cooled feed gas stream. An expander receives at least a portion of the cooled feed gas stream. A separation device receives an expanded fluid stream from the expander and separates the expanded fluid stream into a liquid stream containing the selected component and a purified vapor stream having a purified vapor temperature. A compressor receives the purified vapor stream at approximately the purified vapor temperature and produces a compressed vapor stream that is returned to the heat exchanger.

Description

[0001] Priority requirements

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 034112, filed June 3, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to systems and methods for cooling or liquefying gases, and more specifically, to systems and methods for removing selected components from such gases. Background Technology

[0004] Natural gas is typically liquefied under pressure for storage, use, and transportation. The resulting volume reduction from liquefaction allows for the use of more practical and economical container designs.

[0005] Natural gas is typically obtained from underground reservoirs through drilling or similar operations. The resulting natural gas stream is primarily methane, but may contain components such as heavy hydrocarbons (including, for example, butane, ethane, pentane and propane, benzene, xylene, heptane, octane and heavier components), carbon dioxide, hydrogen, nitrogen and water.

[0006] Liquefaction is typically accomplished by cooling natural gas through indirect heat exchange via one or more refrigeration cycles in one or more heat exchangers. If components such as heavy hydrocarbons are present in the gas stream during liquefaction, these components can freeze and impair the operation of the liquefaction heat exchangers. It is also desirable to recover these components as products. Furthermore, high-purity liquefied natural gas produces fewer greenhouse gases such as carbon dioxide when burned as fuel. Summary of the Invention

[0007] Several aspects of this subject matter may be implemented individually or together in the methods, apparatus, and systems described and claimed below. These aspects may be used alone or in combination with other aspects of the subject matter described herein, and the description of these aspects is not intended to exclude the individual use of these aspects or the individual claims of these aspects or the different combinations set forth in the appended claims.

[0008] In one aspect, a system for removing selected components from a gas stream includes a heat exchanger having a first cooling passage configured to receive and provide a cooled feed gas stream. An expansion mechanism causes the receiving of at least a portion of the cooled feed gas stream. A separation device is configured to receive an expanded fluid stream from an expander and separate the expanded fluid stream into a liquid stream containing the selected components and a purified steam stream having a purified steam temperature. A compression mechanism causes the receiving of the purified steam stream at approximately the purified steam temperature and generates a compressed steam stream returned to the heat exchanger.

[0009] In another aspect, a system for liquefying a feed gas includes a heat exchanger having a first cooling passage and a second cooling passage. The first cooling passage is configured to receive a feed gas flow, thereby forming a cooled feed gas flow. A refrigerant mixing compression system is in communication with the heat exchanger and configured to cool the first and second cooling passages. A liquefied gas outlet line is connected to the outlet of the second cooling passage. An expansion mechanism is configured to receive at least a portion of the cooled feed gas flow from the first cooling passage. A separation device is configured to receive an expansion fluid flow from an expander and separate the expansion fluid flow into a liquid flow containing selected components and a purified vapor flow having a purified vapor temperature. A compression mechanism is configured to receive the purified vapor flow at approximately the purified vapor temperature and generate a compressed vapor flow. The second cooling passage is configured to receive and liquefy the compressed vapor flow.

[0010] In another aspect, a method for removing selected components from a gas stream is provided, the method comprising the steps of: cooling a feed gas stream to provide a cooled feed gas stream, expanding the cooled feed gas stream to provide an expanded gas stream, separating the expanded gas stream into a liquid stream containing the selected components and a purified steam stream having a purified steam temperature; and compressing the purified steam stream to provide a compressed steam stream.

[0011] In another aspect, a method for a liquefied gas feed stream includes the following steps: cooling the gas feed stream to provide a cooled feed gas stream, expanding the cooled feed gas stream to provide an expanded gas stream, separating the expanded gas stream into a liquid stream containing selected components and a purified steam stream having a purified steam temperature, compressing the purified steam stream to provide a compressed steam stream, and cooling the compressed steam stream to form a liquefied gas stream. Attached Figure Description

[0012] Figure 1 This is a process flowchart and schematic diagram illustrating the first embodiment of the system disclosed herein;

[0013] Figure 2 This is a process flowchart and schematic diagram illustrating the second embodiment of the system disclosed herein;

[0014] Figure 3 This is a process flowchart and schematic diagram illustrating the third embodiment of the system disclosed herein;

[0015] Figure 4 This is a process flowchart and schematic diagram illustrating the fourth embodiment of the system disclosed herein;

[0016] Figure 5 This is a flowchart and schematic diagram illustrating the fifth embodiment of the system disclosed herein. Detailed Implementation

[0017] Figure 1-5A mixed refrigerant liquefaction system and method incorporating embodiments of the component removal system of this disclosure are shown. It should be noted that although embodiments are illustrated and described below with reference to a system for removing refrigerant components and liquefying natural gas to produce liquefied natural gas, the techniques of this disclosure can be used with systems for liquefying or cooling other types of gases. Furthermore, the techniques of this disclosure can be used to perform the separation of any selected component that is frozen or condensed at a temperature higher than the ultimately desired liquefied natural gas or other product temperature but lower than the inlet temperature of the gas stream.

[0018] refer to Figure 1 The system generally represented by an embodiment of the component removal system of this disclosure is indicated by 10. The system includes a selected component removal system, generally indicated by 12, integrated into a liquefaction system generally indicated by 14. By way of example only, a basic liquefaction system including a mixed refrigerant compressor system may be described in U.S. Patent No. 9,441,877, jointly owned by Gushanas et al., or U.S. Patent No. 10,480,851, to Ducote, Jr., the contents of which are incorporated herein by reference.

[0019] Overall, referring to Figure 1 The system comprises a multi-stream main heat exchanger, generally designated 16, with a hot-end section 18 and a cold-end section 20. The heat exchanger receives a high-pressure natural gas feed stream 22, which is cooled and liquefied in the main heat exchanger by exchanging heat with a refrigeration stream. As a result, a product stream 24 of liquefied natural gas (LNG) is produced. The multi-stream design of the heat exchanger allows for convenient and energy-efficient integration of multiple streams into a single heat exchanger. Suitable heat exchangers, such as brazed aluminum heat exchangers (BAHX), are available from Chart Energy & Chemicals in Ball Ground, Georgia. Plate-fin multi-stream heat exchangers, also available from Chart Energy & Chemicals, offer the further advantage of physical compactness.

[0020] Alternative designs and types of heat exchangers can replace Figure 1 BAHX as shown in Figure 16.

[0021] Including heat exchanger 16 Figure 1 The system can be configured to perform other gas processing options known in the art. These processing options may require the gas stream to exit and re-enter the heat exchanger one or more times, and may include the removal of selected components and the recovery of liquid natural gas, as described in further detail below.

[0022] Heat removal is accomplished in a heat exchanger using a mixed refrigerant, which is processed and readjusted using a mixed refrigerant compressor system, generally indicated by 26. The mixed refrigerant compressor system includes a high-pressure collector 32 that receives and separates the mixed refrigerant (MR) mixed-phase flow 34 after the final compression and cooling cycle. Although a collector drum 32 is shown, alternative separation devices can be used, including but not limited to another type of vessel, cyclone separator, distillation unit, coalescing separator, or mesh or blade demister. A high-pressure vapor refrigerant flow 36 exits the vapor outlet of the collector 32 and proceeds in parallel to the hot end portion 18 of the heat exchanger 16.

[0023] The high-pressure liquid refrigerant stream 38 exits the liquid outlet of the collector 32 and also flows to the hot end of the heat exchanger. After being cooled in the heat exchanger, it flows as a mixed phase stream 40 to the intermediate-temperature riser 42.

[0024] The high-pressure vapor stream 36 from collector 32 is cooled in heat exchanger 16, and the mixed-phase stream 44 flows to cold vapor separator 46. The resulting vapor refrigerant stream 48 exits the vapor outlet of separator 46, and after being cooled in heat exchanger 16, flows as mixed-phase stream 54 to cryogenic riser 52. The vapor and liquid streams 56 and 58 exit cryogenic riser 52 and enter the main refrigeration channel 62 at the cold end 20 of heat exchanger 16.

[0025] The evaporated mixed refrigerant stream 63 exits the hot end 18 of the heat exchanger and, after passing through an optional suction drum 65, is directed to the inlet of the compressor for the initial compression and cooling cycle.

[0026] Liquid stream 64 exits the cold vapor separator 46, is cooled in the heat exchanger 16, and exits the heat exchanger as a mixed-phase stream 66. The mixed-phase stream 66 is directed to the intermediate-temperature riser 42 and mixes with the mixed-phase stream 40 from the liquid outlet of the collector 32. As shown, vapor and liquid streams 72 and 74 exit the intermediate-temperature riser and enter the primary refrigeration passage 62.

[0027] Following the initial compression and cooling cycles, the interstage separator 76 receives and separates the mixed refrigerant phase flow 78. While a separation drum 76 is shown, alternative separation devices can be used, including, but not limited to, another type of vessel, cyclone separator, distillation unit, coalescing separator, or mesh or blade demister. The liquid flow 82 exits the liquid outlet of the interstage separator, is cooled in the heat exchanger 16, and the resulting flow 84 is expanded and directed to the main refrigeration passage 62. The vapor flow 85 exits the vapor outlet of the interstage separator and proceeds in parallel to the final compression and cooling cycle of the compression system. In alternative embodiments of the system, the interstage separator may consist only of a vapor outlet, or it may be omitted entirely.

[0028] According to this disclosure, the component removal system 12 receives a cooled feed gas stream 86, which is generated by cooling the feed gas stream 22 in a first cooling channel 88a of the main heat exchanger 16.

[0029] The cooled feed gas stream 86, after exiting the main heat exchanger 16, is directed to an optional suction drum 92. A vapor stream 94 from the suction drum travels to an expander 96, preferably an expansion turbine, causing the gas stream pressure to drop below a critical pressure. This results in the condensation of the frozen components and / or other components that would condense in the main heat exchanger, forming a mixed-phase stream 98. This mixed-phase stream 98 travels to a separation unit 102, where a liquid stream 104 containing the condensed frozen components and other selected components is removed from the bottom.

[0030] Although the expansion turbine is illustrated as expander 96, alternative expansion devices may be used, including but not limited to expansion valves or orifices.

[0031] By opening the drain valve 106 in the liquid discharge line 108 leading away from the bottom of the suction drum 92, any liquid collected in the suction drum 92 can be directed to the mixed-phase flow 98 traveling to the separator. This prevents potential damage to the expander 96. Alternatively, liquid from the suction drum can flow directly into the separator 102 after exiting valve 106.

[0032] As described above, the suction drum 92, liquid line 108, and drain valve 106 are optional and can therefore be omitted, with the feed stream taken from the main heat exchanger being directed directly to the inlet of expander 96. Alternatively, in an alternative embodiment, the stream directed to the inlet of expander 96 may be slightly heated (e.g., through a passage through a portion of heat exchanger 16 or a dedicated heat exchanger) to evaporate any liquid in the hot gas bypass of the feed stream or feed gas.

[0033] The purified methane-rich vapor stream 112 exits the top of the separator 102 at the purified vapor temperature and is directed to one or more compressors 114, which may be powered by an expander 96 (in a version of the system where the expander is a turbine) or a motor 115 or a combination of both. The compressor is driven by the expander to recover energy from the high-pressure gas stream received by the expander.

[0034] The ideal pressure (“return pressure”) for optimal efficiency of the flow returning to the heat exchanger for liquefaction is the pressure corresponding to the temperature (“return temperature”), which is approximately equal to the temperature of the flow exiting the suction drum or heat exchanger passage 88a. By receiving a steam flow 112 at the purified steam temperature (or approximately at the purified steam temperature due to possible warming as the purified steam flow travels from separator 102 to the compressor inlet), compressor 114 “cold-compresses” the steam flow 112 to a higher pressure and temperature, where the temperature of the compressed flow is approximately equal to or slightly lower than the temperature of the steam in suction drum 92 or the temperature of the cooled gas flow 86 exiting the main heat exchanger. The return temperature of the steam flow 118 exiting the compressor is ideally close to or lower than the temperature of the gas (or flow 86) in suction drum 92 because the system does not heat the steam exiting separator 102 before it enters compressor 114. Furthermore, by introducing cold steam into compressor 114, the pressure of the steam exiting the compressor is higher and the temperature is lower (for the same compressor power level) than if the steam from separator 102 were heated before entering the compressor. As a result, the refrigeration power required for a given level of LNG production is reduced, or conversely, a higher LNG production is achieved if the refrigeration power is fixed. The compressed vapor stream 118 returns to the second cooling channel 88b of the heat exchanger 16 at the return pressure and temperature to be liquefied, thereby producing the LNG product stream 24.

[0035] Although Figure 1 The first and second cooling channels 88a and 88b are shown as part of a single heat exchanger 16, but in alternative embodiments, channels 88a and 88b may be incorporated into separate heat exchangers arranged in series. Furthermore, channels parallel to channel 88a may be formed in the same or additional heat exchangers. This also applies to channel 88b (and the channels corresponding to channels 88a and 88b in the remaining embodiments).

[0036] The process shown is used in natural gas liquefaction processes; however, the system and process shown in 12 can be used in any other process that requires separation of at least a portion of the feed gas at lower pressures and temperatures and benefits from the return of the feed gas at higher pressures.

[0037] like Figure 2 As shown, Figure 1 The component removal system 12 can be implemented as part of a liquefaction process using a coil-wound heat exchanger (CWHX), generally designated 116. Such heat exchangers are well known in the art and, by way of example only, can be purchased from Linde plc of Dublin, Ireland, or Air Products and Chemicals of Allentown, Pennsylvania.

[0038] like Figure 2 As shown, heat exchanger 116 receives a high-pressure natural gas feed stream 122, which is cooled and liquefied in the main heat exchanger by exchanging heat with a refrigeration stream. As a result, a product stream 124 of liquefied natural gas (LNG) is produced.

[0039] The compression system supplies a mixed refrigerant stream to the heat exchanger 116 and receives a mixed refrigerant stream 128 from the heat exchanger 116, and mixes it with the refrigerant stream 128. Figure 1 The mixed refrigerant is regulated in the same way as the compression system 26.

[0040] As is known in the art, the CWHX heat exchanger 116 includes a housing 132 that receives regulated mixed refrigerant streams 134, 136, 138, and 140. Mixed refrigerant stream 134 is formed by cooling and expanding a vapor stream 142 from a cold vapor separator 144. Mixed refrigerant stream 136 is formed by cooling and expanding a liquid stream 146 from a cold vapor separator 144. Mixed refrigerant stream 138 is formed by cooling and expanding a liquid stream 148 from a high-pressure collector 152. Mixed refrigerant stream 140 is formed by cooling and expanding a liquid stream 154 from an interstage separator 156.

[0041] The cooling passages 188a and 188b of the heat exchanger 116, as well as the passage for cooling the mixed refrigerant, are formed by a tube bundle wound around a core or mandrel and located within the housing 132 of the heat exchanger. As a result, the outer surface of the tube bundle is exposed to the mixed refrigerant flows 134, 136, 138, and 140 entering the housing.

[0042] Similar to Figure 1 The system and process, in which component removal system 12 receives a cooled gas feed stream 186, which is generated by cooling the feed gas stream 122 in the first cooling channel 188a of the main heat exchanger 116. The cooled gas feed stream 186 in component removal system 12 is in accordance with the above-referenced... Figure 1 The same process is performed, and the compressed vapor stream 190 is returned to the second cooling channel 188b of the heat exchanger 116 to be liquefied, thereby producing an LNG product stream 124.

[0043] exist Figure 3 In this context, alternative embodiments of the component removal system are generally indicated by 200. The liquefaction system 14 is associated with... Figure 1 It operates in the same manner as shown, and therefore also includes a main heat exchanger 16, which includes first and second cooling channels 88a and 88b.

[0044] As described below, Figure 3 The component removal system 200 uses stripping gas to remove light components from frozen components and other selected components, so that the light components are added to the LNG product stream.

[0045] refer to Figure 3 Furthermore, as in the preceding embodiments, the natural gas feed stream 202 is cooled and liquefied in the main heat exchanger 16 by removing heat through heat exchange with the refrigeration stream. As a result, a product stream 204 of liquefied natural gas (LNG) is produced.

[0046] The component removal system 200 receives a cooled gas feed stream 206, which is generated by cooling the feed gas stream 202 in the first cooling channel 88a of the main heat exchanger 16.

[0047] The cooled feed gas stream 206, after exiting the main heat exchanger 16, is directed to an optional suction drum 208. The vapor stream 210 from the suction drum travels to an expander 212, preferably an expansion turbine, causing the gas stream pressure to drop below a critical pressure. This results in the condensation of the frozen components and / or other selected components that will condense in the main heat exchanger, thus forming a mixed-phase flow 214. Although the expansion turbine is illustrated as an expander 212, alternative expansion devices, including but not limited to expansion valves or orifices, can be used.

[0048] The mixed-phase flow 214 proceeds to a separation tower, generally designated 216. Tower 216 includes a separation section 218 and a stripping section 220. As is known in the art, the stripping section 220 may include mesh mats, trays, packing, and similar components.

[0049] The mixed phase flow 214 enters the separation section 218 of the tower and is separated into vapor and liquid portions. The liquid portion flows downward into the stripping section 220 directly and / or through internal or external distribution devices, including, for example, distribution lines 224 and distribution devices 226.

[0050] Stripping gas is supplied via stripping gas line 228, which, under the control of valve 230, directs a portion of the feed gas stream 202 to the bottom of stripping section 220. Alternatively, the stripping gas can be extracted from stream 88a at a lower temperature.

[0051] A liquid stream 232 containing condensed freezing components and other selected components is discharged from the bottom of tower 216.

[0052] Any liquid collected in suction drum 208 can be directed to stripping section 220 of tower 216 by opening drain valve 236 in liquid line 234 leading away from the bottom of suction drum 208. This prevents potential damage to expander 212.

[0053] The suction drum 208, liquid line 234, and drain valve 236 are optional and can therefore be omitted. The feed stream taken from the main heat exchanger is directly directed to the inlet of the expander 212.

[0054] The purified, methane-rich vapor stream 238 exits the top of the separation tower 216 and is directed to the compressor 242, which may be powered by an expander 212 (in a version where the expander is a turbine) or a motor 244, or a combination of both. By receiving the vapor stream at the temperature of the separation unit, the compressor 242 “cold-compresses” the vapor stream 238 to a higher pressure and temperature, wherein the temperature of the compressed gas stream is ideally approximately equal to or slightly lower than the temperature of the steam in the suction drum 208 or the temperature of the cooled gas stream 206 taken from the main heat exchanger. The outlet temperature of the vapor stream 246 exiting the compressor is close to or lower than the temperature of the gas (or stream 206) in the suction drum 208 because the system does not heat the vapor leaving the separation tower 216 before it enters the compressor 242. Furthermore, by allowing cold steam to enter the compressor 242, the pressure of the vapor leaving the compressor is higher than if the vapor from the separation tower 216 were heated before entering the compressor (for the same compressor power level). As a result, the refrigeration power required for a given level of LNG production is reduced, or conversely, a higher LNG production is achieved if the refrigeration power is fixed. The compressed vapor stream 246 returns to the second cooling channel 88b of the heat exchanger 16 to be liquefied, thereby producing the LNG product stream 204.

[0055] Figure 3 The system's alternative version is Figure 4 As shown, the stripping section of the separation tower incorporates a reboiler service. More specifically, in Figure 4 The component removal system, generally designated 300, includes a separation tower 302 having a separation section 304 and a stripping section 306. A liquid stream 308 containing condensed frozen components and other selected components is drawn from the bottom of the tower 302. Additionally, a reboiler service, including a reboiler heat exchanger 312, receives a reboiler liquid stream 314 from the stripping section 306 of the tower. The heat exchanger 312 also receives and cools an output gas stream 316 diverted from the main natural gas feed stream 318 entering the liquefaction system. As a result, the liquid stream 314 from the tower is at least partially evaporated, and the resulting vapor stream 322 is returned to the stripping section 306 of the tower as stripped gas. The cooled output gas stream 324 exits the reboiler heat exchanger 312 and is directed to an optional suction drum 326. In embodiments omitting the suction drum 326, the cooled output gas stream 324 may be combined with the vapor stream 328 entering the expander 332. In alternative embodiments, stream 316 may be diverted from stream 88a (… Figure 1 (or any other stream taken from the heating medium)

[0056] Figure 4 The remaining aspects of the contamination system 300, separation tower 302, and liquefaction system 14 are consistent with those described above. Figure 3 Operate in the same way as described above.

[0057] exist Figure 5 In this context, alternative embodiments of the component removal system are generally indicated by 400. The liquefaction system 14 is associated with... Figure 1 It operates in the same manner as shown. Except for the handling of the outlet flow 412 of compressor 414, Figure 5 The rest of the system and Figure 3 The system is the same. Figure 5 The processing of the compressor outlet flow can be used in any of the above embodiments.

[0058] System 400 includes a main heat exchanger 406, which includes a hot end portion 406, a cold end portion 410, and first and second cooling channels 408a and 408b. Figure 5 As shown, the second cooling channel 408b is configured as a high-pressure channel, which at least partially passes through the hot end portion 406 and the cold end portion 410 of the heat exchanger.

[0059] exist Figure 5 In this embodiment, the compressor intake is maintained at approximately the purge steam temperature, where, as in the previous embodiment, the purge steam temperature is the temperature of the steam stream 416 exiting the top of the separator 418. The compressor discharge pressure and the pressure of stream 412 increase (relative to the above embodiment) to a point where stream 412 is at a higher temperature than stream 422 entering expander 424 (or optional suction drum 426). As a result, gas stream 412 is hotter than in the previous embodiment, and therefore gas stream 412 is directed to high-pressure gas passage 408b. In this embodiment, it may be necessary to power the compressor via an optional motor 428 (either by itself or in addition to the power provided by the expander turbine 424). Furthermore, an optional compressor discharge regulating heat exchanger 430 may be provided to regulate (either cooling or heating) stream 412 and provide thermal integration with liquefaction, condensation systems, or other processes before entering the heat exchanger.

[0060] The component removal system embodiment described above recompresses the gas from the separation unit, where selected components are removed from the gas without heating it, resulting in cold compressor suction, i.e., at the temperature of the separation unit. The power required for compression and the compressor discharge temperature are proportional to the suction temperature. Therefore, with a fixed available power and the desired return temperature and pressure of the main heat exchanger, cold compression allows for a higher compressor discharge pressure and a lower temperature than when the suction first warms up. As a result, the refrigeration power required for a given level of liquefied natural gas production is reduced, or conversely, a higher liquefied natural gas production is obtained if the refrigeration power is fixed.

[0061] While preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications can be made thereto without departing from the spirit of the invention, the scope of which is defined by the appended claims.

Claims

1. A system for removing selected components from a gas stream, comprising: a. A heat exchanger including a first cooling passage configured to receive a feed gas flow and provide a cooled feed gas flow; b. An expander configured to receive at least a portion of a cooled feed gas stream; c. A separation device having a separation device steam outlet, the separation device being configured to receive an expanding fluid flow from an expander and separate the expanding fluid flow into a liquid flow containing selected components and a purified steam flow having a purified steam temperature; and d. A compressor configured to receive a purified steam stream at the purified steam temperature directly from the steam outlet of the separation unit and generate a compressed steam stream that returns to the heat exchanger, wherein the compressed steam stream is compressed to a pressure corresponding to a temperature equal to the temperature of the cooling gas stream.

2. The system of claim 1, further comprising a second cooling passage configured to receive the compressed steam flow, wherein, The heat exchanger includes a single main heat exchanger, which includes the first and second cooling channels.

3. The system of claim 1, further comprising a second cooling passage configured to receive the compressed steam flow, wherein, The heat exchanger includes a first heat exchanger containing the first cooling channel and a second heat exchanger containing the second cooling channel.

4. The system according to claim 1, further comprising: A second cooling channel is configured to receive the compressed steam flow; A third cooling channel, arranged parallel to the first cooling channel, such that the first and third cooling channels receive the feed gas flow and provide a cooled feed gas flow to the expander; and a fourth cooling channel, arranged parallel to the second cooling channel, such that the second and fourth cooling channels receive a compressed steam flow.

5. The system according to claim 4, wherein, The first and second cooling channels are located in the first heat exchanger, and the third and fourth cooling channels are located in the second heat exchanger.

6. The system of claim 1 further includes a regulating heat exchanger configured to receive compressed steam from the compressor and direct regulated compressed steam to the heat exchanger.

7. The system of claim 1 further includes a suction drum configured to receive a cooled feed gas stream from the first cooling passage of the heat exchanger, the suction drum having a suction steam outlet configured to direct at least a portion of the cooled feed gas stream to the expander.

8. The system according to claim 7, wherein, The suction drum has a suction liquid outlet and also includes a liquid discharge line configured to guide the fluid flow to the separation device.

9. The system according to claim 8, wherein, The liquid discharge line includes a discharge valve.

10. The system according to claim 1, wherein, The expander is an expansion turbine.

11. The system according to claim 10, wherein, The compressor is powered by the expansion turbine.

12. The system according to claim 11, wherein, The compressor is powered by the expansion turbine and the motor.

13. The system according to claim 1, wherein, The expander is powered by a motor.

14. The system according to claim 1, wherein, The separation device includes a separation tower having a separation section and a stripping section, wherein the separation section is configured to receive an expanded fluid flow from the expander, direct the liquid to the stripping section, direct the purified steam flow to the compressor, and the contaminated liquid flow exits the stripping section; It also includes a stripping gas pipeline, which is configured to receive a portion of the feed gas flow and direct that portion of the feed gas flow to the stripping section for use as stripping gas.

15. The system according to claim 14, wherein, The stripping gas line includes an inlet configured to receive fluid from a first cooling passage of the heat exchanger.

16. The system of claim 14, further comprising a suction drum configured to receive a cooled feed gas flow from a first cooling passage of the heat exchanger, the suction drum having a suction drum steam outlet configured to direct at least a portion of the cooled feed gas flow to the expander and a suction drum liquid outlet configured to direct a fluid flow to the stripping section.

17. The system according to claim 1, wherein, The separation device includes a separation tower having a separation section and a stripping section, wherein the separation section is configured to receive an expanded fluid flow from the expander, direct the liquid to the stripping section, direct the purified steam flow to the compressor, and the liquid flow containing the selected components exits the stripping section; And also includes: A reboiler heat exchanger configured to receive a reboiler liquid stream from a stripping section to at least partially evaporate the reboiler liquid stream and to direct the resulting stripping gas stream to the stripping section.

18. The system of claim 17, further comprising an output gas line configured to receive a portion of the feed gas stream and direct said portion of the feed gas stream to the reboiler heat exchanger, wherein, The portion of the feed gas stream is cooled as the reboiler liquid stream is heated and evaporated, and wherein the reboiler heat exchanger is configured to direct at least a portion of the cooled portion of the feed gas stream to the expander.

19. The system of claim 1, further comprising a second cooling passage configured to receive the compressed steam flow, wherein, The first and second cooling channels are positioned in parallel within the heat exchanger.

20. The system according to claim 19, wherein, The heat exchanger includes a hot end portion and a cold end portion, the second cooling channel forms a high-pressure channel that at least partially passes through the hot end portion and the cold end portion of the heat exchanger, and wherein the first cooling channel passes through at least a portion of the hot end portion of the heat exchanger.

21. The system of claim 20 further includes a regulating heat exchanger configured to receive compressed steam from the compressor and direct the regulated compressed steam to the high-pressure passage.

22. A system for liquefying feed gas, comprising: a. A heat exchanger having a first cooling channel and a second cooling channel, the first cooling channel being configured to receive a feed gas flow, thereby forming a cooled feed gas flow; b. A mixed refrigerant compression system, which is connected to a heat exchanger and configured to cool first and second cooling channels; c. A liquefied gas outlet pipeline that connects to the outlet of the second cooling passage; d. An expander configured to receive at least a portion of a cooled feed gas stream from a first cooling passage; e. A separation device having a separation device steam outlet, the separation device being configured to receive an expansion fluid flow from an expander and separate the expansion fluid flow into a liquid flow containing selected components and a purified steam flow having a purified steam temperature; f. A compressor configured to receive a purified steam stream at the purified steam temperature directly from the steam outlet of the separation device and to generate a compressed steam stream, wherein the compressed steam stream is compressed to a pressure corresponding to a temperature equal to the temperature of the cooling gas stream. g. The second cooling channel is configured to receive and liquefy compressed vapor flow; h. Wherein, the separation device includes a separation tower having a separation section and a stripping section, wherein the separation section is configured to receive an expanded fluid flow from the expander, direct the liquid to the stripping section, and direct the purified steam flow to the compressor, and a liquid flow containing selected components exits the stripping section; and i. A stripping gas line configured to receive a steam portion of a feed gas stream at the feed gas stream temperature and to direct the steam portion of the feed gas stream to a stripping section for use as stripping gas.

23. The system according to claim 22, wherein, The heat exchanger includes a single main heat exchanger, which includes the first and second cooling channels.

24. The system according to claim 22, wherein, The heat exchanger includes a first heat exchanger containing the first cooling channel and a second heat exchanger containing the second cooling channel.

25. The system according to claim 22, further comprising: A third cooling channel is arranged parallel to the first cooling channel, such that the first and third cooling channels receive the feed gas flow and provide a cooled feed gas flow to the expander; And a fourth cooling channel, which is arranged parallel to the second cooling channel, such that the second and fourth cooling channels receive and liquefy the compressed vapor flow.

26. The system according to claim 25, wherein, The first and second cooling channels are located in the first heat exchanger, and the third and fourth cooling channels are located in the second heat exchanger.

27. The system of claim 22 further includes a regulating heat exchanger configured to receive compressed steam from the compressor and direct regulated compressed steam to the heat exchanger.

28. The system of claim 22 further includes a suction drum configured to receive a cooled feed gas stream from the first cooling passage of the heat exchanger, the suction drum having a suction steam outlet configured to direct at least a portion of the cooled feed gas stream to the expander.

29. The system according to claim 28, wherein, The suction drum has a suction liquid outlet and also includes a liquid discharge line configured to guide the fluid flow to the separation device.

30. The system according to claim 29, wherein, The liquid discharge line includes a discharge valve.

31. The system according to claim 22, wherein, The expander is an expansion turbine.

32. The system according to claim 31, wherein, The compressor is powered by the expansion turbine.

33. The system according to claim 31, wherein, The compressor is powered by the expansion turbine and the motor.

34. The system according to claim 22, wherein, The compressor is powered by a motor.

35. The system according to claim 22, wherein, The separation device includes a separation tower having a separation section and a stripping section, wherein the separation section is configured to receive an expanded fluid flow from the expander, direct the liquid to the stripping section, direct the purified steam flow to the compressor, and the liquid flow containing selected components exits the stripping section; It also includes a stripping gas pipeline configured to receive a portion of the feed gas flow and direct the portion of the feed gas flow to the stripping section for use as stripping gas.

36. The system according to claim 35, wherein, The stripping gas line includes an inlet configured to receive fluid from a first cooling passage of the heat exchanger.

37. The system of claim 35 further includes a suction drum configured to receive a cooled feed gas flow from a first cooling passage of the heat exchanger, the suction drum having a suction drum steam outlet configured to direct at least a portion of the cooled feed gas flow to the expander and a suction drum liquid outlet configured to direct a fluid flow to the stripping section.

38. The system according to claim 22, wherein, The separation device includes a separation tower having a separation section and a stripping section, wherein the separation section is configured to receive an expanded fluid flow from the expander, direct the liquid to the stripping section, direct the purified steam flow to the compressor, and the liquid flow containing the components exits the stripping section; And also includes: A reboiler heat exchanger configured to receive a reboiler liquid stream from a stripping section to heat and at least partially evaporate the reboiler liquid stream, and to direct the resulting stripping gas stream to the stripping section.

39. The system of claim 38, further comprising an output gas line configured to receive a portion of the feed gas stream and direct said portion of the feed gas stream to the reboiler heat exchanger, wherein, The portion of the feed gas stream is cooled as the reboiler liquid stream is heated and partially evaporated, and wherein the reboiler heat exchanger is configured to direct at least a portion of the cooled portion of the feed gas stream to the expander.

40. The system according to claim 22, wherein, The heat exchanger includes a hot end portion and a cold end portion, the second cooling channel forms a high-pressure channel that at least partially passes through the hot end portion and the cold end portion of the heat exchanger, and wherein the first cooling channel passes through at least a portion of the hot end portion of the heat exchanger.

41. The system of claim 40 further includes a regulating heat exchanger configured to receive compressed steam from the compressor and direct the regulated compressed steam to a high-pressure passage.

42. A method for removing selected components from a gas stream, comprising the following steps: a. Cooling the feed gas stream to provide a cooled feed gas stream; b. An expansion-cooled feed gas flow to provide an expansion gas flow; c. Using a separation device with a steam outlet, the expanded gas stream is separated into a liquid stream containing selected components and a purified steam stream with purified steam temperature; and d. After the compressor receives the purified steam stream at the purified steam temperature directly from the steam outlet of the separator, the compressor is used to compress the purified steam stream to provide a compressed steam stream, wherein the compressed steam stream is compressed to a pressure corresponding to a temperature equal to the temperature of the cooling gas stream.

43. The method according to claim 42, wherein, The gas flow is a natural gas flow.

44. A method for feeding a liquefied gas stream, comprising the following steps: a. Cooling the feed gas stream to provide a cooled feed gas stream; b. An expansion-cooled feed gas flow to provide an expansion gas flow; c. Using a separation device with a steam outlet, the expanded gas stream is separated into a liquid stream containing selected components and a purified steam stream with purified steam temperature; d. After the compressor receives the purified steam stream at the purified steam temperature directly from the steam outlet of the separator, the compressor compresses the purified steam stream to provide a compressed steam stream, wherein the compressed steam stream is compressed to a pressure corresponding to a temperature equal to the temperature of the cooling gas stream; and e. Cooling and compressing the vapor stream to form a liquefied gas stream.

45. The method according to claim 44, wherein, The gas flow is a natural gas flow.

Images