Coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process integrating dehydrogenation
By integrating coalbed methane helium extraction and high-purity methane co-production processes through dehydrogenation, and employing cryogenic distillation and two-stage membrane-PSA technology combined with nitrogen expansion refrigeration, the problems of lengthy coalbed methane helium extraction processes and safety risks in existing technologies have been solved. This has enabled the efficient production of high-purity helium and methane products, while reducing energy consumption and equipment investment.
Patent Information
- Application Number
- CN202511406048.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-24
- Publication Date
- 2025-12-30
AI Technical Summary
Existing coalbed methane helium extraction technologies suffer from problems such as lengthy process flow, high safety risks in hydrogen removal processes, failure to efficiently co-produce high-value methane products, and poor overall economic efficiency.
A process for recovering methane by cryogenic distillation coupled with a two-stage membrane-PSA integrated helium extraction process is adopted. Combined with an integrated dehydrogenation PSA unit, hydrogen and other impurities are removed simultaneously and deeply to produce high-purity liquefied natural gas and high-purity helium. Nitrogen expansion cycle refrigeration is used to achieve cascade utilization of cooling capacity.
It achieves efficient production of high-purity helium and high-purity methane products. The process is safe and reliable, with low overall energy consumption, low equipment investment, strong adaptability, and is suitable for low-grade coalbed methane resources.
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Figure CN121230366A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical separation technology and relates to helium extraction from coalbed methane, specifically to an integrated dehydrogenation process for the co-production of helium from coalbed methane with high-purity methane and / or liquefied natural gas (LNG). Background Technology
[0002] Helium, a colorless, odorless, non-toxic, and non-flammable inert light gas, is widely used in cryogenic engineering, biomedicine, semiconductor manufacturing, and scientific research due to its extremely low boiling point, high diffusivity, poor water solubility, and good thermal conductivity. Currently, extraction from helium-containing natural gas remains the primary industrial method for obtaining helium.
[0003] Coalbed methane (CBM), as an unconventional natural gas resource, contains low concentrations of helium (typically between 0.1% and 0.5%) in some producing areas, representing a potential helium resource. However, extracting helium from low-grade CBM faces the following technical challenges: traditional catalytic oxidation dehydrogenation processes pose safety risks due to the introduction of oxygen, and are lengthy and energy-intensive; conventional pressure swing adsorption (PSA) or membrane separation technologies struggle to efficiently extract helium while simultaneously removing hydrogen impurities to obtain high-purity helium; furthermore, existing processes primarily focus on helium extraction, failing to efficiently recover methane, the main component of CBM, resulting in poor overall system energy efficiency and economic viability.
[0004] Therefore, developing a comprehensive coalbed methane utilization process that can efficiently produce high-purity helium while simultaneously recovering and utilizing high-purity methane, and which is safe and energy-efficient, has significant application value. Based on this, this invention proposes an integrated dehydrogenation process for the co-production of helium from coalbed methane with high-purity methane and / or liquefied natural gas (LNG). Summary of the Invention
[0005] To address the problems of lengthy process flows, safety risks in hydrogen removal processes, inefficient co-production of high-value methane, and poor overall economic efficiency in existing coalbed methane helium extraction technologies, this invention aims to provide an integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process. This process employs cryogenic distillation to recover methane coupled with a two-stage membrane-PSA integrated helium extraction system. It innovatively utilizes an integrated dehydrogenation PSA unit to simultaneously and deeply remove hydrogen and other impurities, simultaneously producing both high-purity LNG and high-purity helium. The main component of the high-purity LNG is methane, with a methane purity exceeding 99.5%. Under the same conditions, this process offers advantages such as high helium recovery rate, safe and reliable process flow, high methane product purity, low overall energy consumption, and lower equipment investment compared to other processes.
[0006] To achieve the above objectives, this invention provides an integrated dehydrogenation process for the co-production of helium from coalbed methane and high-purity methane and / or liquefied natural gas (LNG), comprising a pretreatment unit, a decarbonization unit, a recompression and precooling unit, a methane purification and light hydrocarbon recovery unit, a two-stage membrane helium extraction unit, an integrated purification unit, and a nitrogen expansion cycle refrigeration unit.
[0007] The pretreatment unit includes separators S-1, S-2, and S-3, mixer M-1, compressor K-1, cooler E-1 and E-2, filter F-1, molecular sieve dryer D-1-A / B, heater H-1, throttle valve VLV-1, and waste liquid collection tank V-1; the decarbonization unit includes a five-tower pressure swing adsorption decarbonization system PSA-1-A to E; the recompression and precooling unit includes compressor K-2, cooler E-3, and heat exchanger HX-1; the methane purification and light hydrocarbon recovery unit includes a cryogenic separator S-4. The system includes a mixer M-2, a demethanizer T-1, a cryogenic pressurization pump P-1, a subcooler E-4, a heat exchanger HX-2, a reflux tank V-2, and a reflux pump P-2; the two-stage membrane helium extraction unit includes a heater H-2, a first-stage membrane separator OP-1, and a second-stage membrane separator OP-2; the integrated purification unit includes a five-tower integrated dehydrogenation pressure swing adsorption system PSA-2-A~E and a temperature swing adsorber TSA-1; the nitrogen expansion cycle refrigeration unit includes a heat exchanger HX-1, a heat exchanger HX-2, an expander EXP-1, a compressor K-3, and a cooler E-5;
[0008] The pretreatment unit has a coalbed methane inlet pipe connected to the inlet of separator S-1; separator S-1 separates the gas into two streams, a gas phase and a liquid phase, with the liquid phase outlet connected to the inlet of waste liquid collection tank V-1; the gas phase outlet of separator S-1 is sequentially connected to mixer M-1, compressor K-1, cooler E-1, and the inlet of separator S-2; separator S-2 separates the gas into two streams, a gas phase and a liquid phase, with the liquid phase outlet connected to the inlet of waste liquid collection tank V-1; the gas phase outlet of separator S-2 is connected to filter F-1 and molecular sieve dryer D-1-A / The top inlet of B is connected sequentially; a branch line branches off from the bottom outlet main pipe of molecular sieve dryer D-1-A / B, which is connected sequentially to throttle valve VLV-1, heater H-1, and the bottom inlet of molecular sieve dryer D-1-A / B; the top outlet of molecular sieve dryer D-1-A / B is connected sequentially to cooler E-2 and separator S-3 inlet; separator S-3 separates into gas and liquid phases, with the liquid phase being condensate; the gas phase outlet of separator S-3 is connected to mixer M-1 and returns to compressor K-101 inlet;
[0009] The decarbonization unit has a bottom outlet manifold of molecular sieve dryer D-1-A / B connected to the inlet of pressure swing adsorption decarbonization system PSA-1-A~B; the top outlet of pressure swing adsorption decarbonization system PSA-1-A~B is connected to compressor K-2, and desorption gas flows out from the bottom outlet, separating high-concentration CO2.
[0010] The recompression and precooling unit is connected in sequence to compressor K-2, cooler E-3, heat exchanger HX-1, and inlet of cryogenic separator S-4. Cryogenic separator S-4 separates gas and liquid phases. The liquid phase outlet is connected to mixer M-2 and top inlet of demethanizer T-1. The gas phase outlet of cryogenic separator S-4 is connected to the middle inlet of demethanizer T-1.
[0011] The methane purification and light hydrocarbon recovery unit has its bottom outlet of the demethanizer T-1 connected in sequence to the cryogenic pressurization pump P-1 and the subcooler E-4, separating methane and / or liquefied natural gas (LNG); the top outlet of the demethanizer T-1 is connected in sequence to the heat exchanger HX-2 and the inlet of the reflux tank V-2; the liquid phase outlet of the reflux tank V-2 is connected in sequence to the reflux pump P-2, the mixer M-2, and the top inlet of the demethanizer.
[0012] The two-stage membrane helium extraction unit has its reflux tank V-2 gas phase outlet connected sequentially to heater H-2, primary membrane separator OP-1, and secondary membrane separator OP-2 inlet to extract crude helium; the residual gas outlet of primary membrane separator OP-1 is connected to mixer M-1 and returns to compressor K-1 inlet; the residual gas outlet of secondary membrane separator OP-2 is connected to primary membrane separator OP-1 inlet.
[0013] The integrated purification unit has its permeate outlet of the secondary membrane separator OP-2 connected in sequence to the integrated dehydrogenation pressure swing adsorption system PSA-2-A~E and the inlet of the temperature swing adsorber TSA-1, separating out refined helium.
[0014] The nitrogen expansion cycle refrigeration unit is connected in sequence with the compressor K-3 outlet to the cooler E-5, the refrigerant channel of the heat exchanger HX-1, and the inlet of the expander EXP-1; the expander EXP-1 outlet is connected in sequence with the refrigerant channel of the heat exchanger HX-2 and the inlet of the refrigerant channel of the heat exchanger HX-1, and returns to the compressor K-3 inlet, forming a closed loop cycle.
[0015] The above-mentioned integrated dehydrogenation coalbed methane helium extraction and co-production process with high-purity methane and / or liquefied natural gas (LNG) can use helium-containing coalbed methane at room temperature and different pressures (atmospheric to medium pressure) as feed gas. It is especially suitable for processing low-grade coalbed methane resources with helium concentration as low as 0.1% and carbon dioxide concentration as high as 30%. It has a wide range of applicable process conditions and strong adaptability.
[0016] The aforementioned integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process utilizes heat exchangers HX-1 and HX-2, whose main function is to achieve heat exchange and transfer during the production process. These are conventional devices in the field. In this invention, heat exchanger HX-1 is provided with a first heat exchange channel, a second heat exchange channel, and a third heat exchange channel.
[0017] The first heat exchange channel is connected to the compressor K-3 via a pipe at its beginning and to the heat exchanger HX-2 via a pipe at its end. The second heat exchange channel is connected to the expander EXP-1 via a pipe at its beginning and to the cooler E-5 via a pipe at its end. The cooler E-3 is connected to the first end of the third heat exchange channel via a pipe at its end and to the cryogenic separator S-4 via a pipe at its end.
[0018] In this invention, the heat exchanger HX-2 is provided with a fourth heat exchange channel and a fifth heat exchange channel;
[0019] The first end of the fourth heat exchange channel is connected to the end of the first heat exchange channel of heat exchanger HX-1 via a pipe, and the end of the fourth heat exchange channel is connected to the expander EXP-1 via a pipe; the first end of the fifth heat exchange channel is connected to the demethanizer T-1 via a pipe, and the end of the fifth heat exchange channel is connected to the reflux tank V-2 via a pipe.
[0020] The aforementioned integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process comprises a high-purity liquid methane production loop consisting of separator S-1, mixer M-1, compressor K-1, cooler E-1, separator S-2, filter F-1, molecular sieve dryer D-1-A / B, pressure swing adsorption decarbonization system PSA-1, A~E, compressor K-2, cooler E-3, heat exchanger HX-1, cryogenic separator S-4, demethanizer T-1, cryogenic pressurization pump P-1, subcooler E-4, and connecting pipelines between adjacent components; and a high-purity helium production loop consisting of the top of demethanizer T-1, heat exchanger HX-2, reflux tank V-2, heater H-2, primary membrane separator OP-1, secondary membrane separator OP-1, integrated dehydrogenation pressure swing adsorption system PSA-2-A~E, temperature swing adsorber TSA-1, and connecting pipelines between adjacent components.
[0021] The aforementioned integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process includes an integrated refrigeration system. This system employs a nitrogen expansion refrigeration cycle, utilizing heat exchangers HX-1 and HX-2 to provide cooling for the feed precooling and top condensation of the demethanizer tower T-1. This achieves cascaded utilization and efficient integration of cooling capacity within the system, significantly reducing overall energy consumption.
[0022] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:
[0023] (1) The integrated dehydrogenation process for coalbed methane helium extraction and co-production of high-purity methane and / or liquefied natural gas (LNG) provided by this invention purifies and concentrates helium in the raw coalbed methane through a demethanizer, membrane separation system, and integrated dehydrogenation pressure swing adsorption system to obtain high-purity helium; simultaneously, high-purity liquefied methane is obtained through deep separation in the demethanizer. This invention innovatively integrates and optimizes traditional coalbed methane liquefaction and helium extraction processes. The process integration enables equipment sharing and cascaded energy utilization, reduces resource waste, and simultaneously produces two high-value-added products: high-purity helium and high-purity liquefied methane.
[0024] (2) The integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process provided by the present invention adopts an integrated dehydrogenation pressure swing adsorption system to simultaneously and deeply remove impurities such as hydrogen and nitrogen. The helium product produced has high purity, low overall energy consumption of the equipment, safe and reliable process flow and low equipment investment.
[0025] (3) The process of this invention has wide adaptability and can efficiently process low-quality coalbed methane with high carbon dioxide and low helium concentration, and achieve extremely high methane recovery rate, providing an effective technical solution for the clean, efficient and high-value utilization of such resources. Attached Figure Description
[0026] Figure 1 This is a process flow diagram of the integrated dehydrogenation coalbed methane helium extraction and co-production of high-purity methane and / or liquefied natural gas (LNG) according to the present invention.
[0027] Explanation of reference numerals in the attached diagram: S-1-Separator; M-1-Mixer; E-1-Cooler; V-1-Waste liquid collection tank; F-1-Filter; D-1-A / B-Molecular sieve dryer; E-2-Cooler; S-3-Separator; VLV-1-Throttle valve; H-1-Heater; PSA-1-A~E-Pressure swing adsorption decarbonization system for five towers; K-2-Compressor; E-3-Cooler; HX-1-Heat exchanger; S-4-Cryogenic separation tank M-4 - Mixer; T-1 - Demethanizer; P-1 - Cryogenic pressurization pump; E-4 - Subcooler; HX-2 - Heat exchanger; V-2 - Reflux tank; P-2 - Reflux pump; H-2 - Heater; OP-1 - Primary membrane separator; OP-2 - Secondary membrane separator; PSA-2 - Integrated dehydrogenation pressure swing adsorption system for five towers (A to E); TSA-1 - Temperature swing adsorber; K-3 - Compressor; E-5 - Cooler; EXP-1 - Expander. Detailed Implementation
[0028] The following will be combined with the appendix Figure 1The integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process technology provided by the present invention is clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention.
[0029] This embodiment provides an integrated dehydrogenation process for helium extraction from coalbed methane and co-production of high-purity methane and / or liquefied natural gas (LNG), such as... Figure 1 As shown, it includes a pretreatment unit, a decarbonization unit, a recompression and precooling unit, a methane purification and light hydrocarbon recovery unit, a two-stage membrane helium extraction unit, an integrated purification unit, and a nitrogen expansion cycle refrigeration unit connected by pipelines.
[0030] The pretreatment unit includes separator S-1, separator S-2, separator S-3, mixer M-1, compressor K-1, cooler E-1, cooler E-2, filter F-1, molecular sieve dryer D-1-A / B, heater H-1, throttle valve VLV-1, and waste liquid collection tank V-1.
[0031] The decarbonization unit includes a five-tower process pressure swing adsorption decarbonization system PSA-1-A~E.
[0032] The recompression and precooling unit includes compressor K-2, cooler E-3, and heat exchanger HX-1. Heat exchanger HX-1 is provided with a first heat exchange channel, a second heat exchange channel, and a third heat exchange channel.
[0033] The methane purification and light hydrocarbon recovery unit includes a cryogenic separator S-4, a mixer M-2, a demethanizer T-1, a cryogenic pressurization pump P-1, a subcooler E-4, a heat exchanger HX-2, a reflux tank V-2, and a reflux pump P-2. The heat exchanger HX-2 is equipped with a fourth heat exchange channel and a fifth heat exchange channel.
[0034] The two-stage membrane helium extraction unit includes heater H-2, primary membrane separator OP-1, and secondary membrane separator OP-2.
[0035] The integrated purification unit includes an integrated dehydrogenation pressure swing adsorption system PSA-2-A~E and a temperature swing adsorber TSA-1.
[0036] The nitrogen expansion cycle refrigeration unit includes heat exchanger HX-1, heat exchanger HX-2, expander EXP-1, compressor K-3, and cooler E-5.
[0037] The first heat exchange channel is connected to the compressor K-3 via a pipe at its beginning and to the heat exchanger HX-2 via a pipe at its end. The second heat exchange channel is connected to the expander EXP-1 via a pipe at its beginning and to the cooler E-5 via a pipe at its end. The cooler E-3 is connected to the first end of the third heat exchange channel via a pipe at its end and to the cryogenic separator S-4 via a pipe at its end.
[0038] The first end of the fourth heat exchange channel is connected to the end of the first heat exchange channel of heat exchanger HX-1 via a pipe, and the end of the fourth heat exchange channel is connected to the expander EXP-1 via a pipe; the first end of the fifth heat exchange channel is connected to the demethanizer T-1 via a pipe, and the end of the fifth heat exchange channel is connected to the reflux tank V-2 via a pipe.
[0039] The aforementioned integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process comprises separator S-1, mixer M-1, compressor K-1, cooler E-1, separator S-2, filter F-1, molecular sieve dryer D-1-A / B, pressure swing adsorption decarbonization system PSA-1-A~E, compressor K-2, cooler E-3, heat exchanger HX-1, cryogenic separator S-4, demethanizer T-1, cryogenic pressurization pump P-1, and a filter... The cooler E-4 and the connecting pipes between adjacent components together constitute the high-purity liquid methane and / or liquefied natural gas (LNG) production circuit; the demethanizer T-1 top, heat exchanger HX-2, reflux tank V-2, heater H-2, primary membrane separator OP-1, secondary membrane separator OP-1, integrated dehydrogenation pressure swing adsorption system PSA-2-A~E, temperature swing adsorber TSA-1, and the connecting pipes between adjacent components together constitute the high-purity helium production circuit.
[0040] The aforementioned integrated dehydrogenation coalbed methane helium extraction and high-purity methane and / or liquefied natural gas (LNG) co-production process includes an integrated refrigeration system. This system employs a nitrogen expansion refrigeration cycle, utilizing heat exchangers HX-1 and HX-2 to provide cooling for the feed precooling and top condensation of the demethanizer tower T-1. This achieves cascaded utilization and efficient integration of cooling capacity within the system, significantly reducing overall energy consumption.
[0041] The integrated dehydrogenation process for coalbed methane helium extraction and co-production of high-purity methane and / or liquefied natural gas (LNG) provided by this invention can use helium-containing coalbed methane at ambient temperature and different pressures (atmospheric to medium pressure). It is particularly suitable for processing low-grade coalbed methane resources with helium concentrations as low as 0.1% and carbon dioxide concentrations as high as 30%. It has a wide range of applicable process conditions and strong adaptability.
[0042] The above description is intended to help readers understand the principles of the present invention, and the scope of protection of the present invention is not limited to such specific statements and embodiments. For those skilled in the art, several combinations and modifications can be made without departing from the principles of the present invention, and these combinations and modifications are also within the scope of protection of the present invention.
Claims
1. A process for the co-production of helium from coalbed methane with high-purity methane and / or liquefied natural gas (LNG) through integrated dehydrogenation, characterized in that: It includes a pretreatment unit, a decarbonization unit, a recompression and precooling unit, a methane purification and light hydrocarbon recovery unit, a two-stage membrane helium extraction unit, an integrated purification unit, and a nitrogen expansion cycle refrigeration unit; The pretreatment unit includes separators S-1, S-2, and S-3, mixer M-1, compressor K-1, cooler E-1 and E-2, filter F-1, molecular sieve dryer D-1-A / B, heater H-1, throttle valve VLV-1, and waste liquid collection tank V-1; the decarbonization unit includes a five-tower pressure swing adsorption decarbonization system PSA-1-A to E; the recompression and precooling unit includes compressor K-2, cooler E-3, and heat exchanger HX-1; the methane purification and light hydrocarbon recovery unit includes a cryogenic separator S-4. The system includes a mixer M-2, a demethanizer T-1, a cryogenic pressurization pump P-1, a subcooler E-4, a heat exchanger HX-2, a reflux tank V-2, and a reflux pump P-2; the two-stage membrane helium extraction unit includes a heater H-2, a first-stage membrane separator OP-1, and a second-stage membrane separator OP-2; the integrated purification unit includes a five-tower integrated dehydrogenation pressure swing adsorption system PSA-2-A~E and a temperature swing adsorber TSA-1; the nitrogen expansion cycle refrigeration unit includes a heat exchanger HX-1, a heat exchanger HX-2, an expander EXP-1, a compressor K-3, and a cooler E-5; The pretreatment unit has a coalbed methane inlet pipe connected to the inlet of feed separator S-1; separator S-1 separates the gas into two streams, a gas phase and a liquid phase, with the liquid phase outlet connected to the inlet of waste liquid collection tank V-1; the gas phase outlet of separator S-1 is sequentially connected to mixer M-1, compressor K-1, cooler E-1, and the inlet of separator S-2; separator S-2 separates the gas into two streams, a gas phase and a liquid phase, with the liquid phase outlet connected to the inlet of waste liquid collection tank V-1; the gas phase outlet of separator S-2 is connected to filter F-1 and molecular sieve dryer D-1-A. The top inlet of the molecular sieve dryer D-1-A / B is connected in sequence; a branch line is branched off from the bottom outlet main pipe of the molecular sieve dryer D-1-A / B, and the branch line is connected in sequence to the throttle valve VLV-1, heater H-1, and the bottom inlet of the molecular sieve dryer D-1-A / B; the top outlet of the molecular sieve dryer D-1-A / B is connected in sequence to the inlet of the cooler E-2 and the separator S-3; the separator S-3 separates two streams, a gas phase and a liquid phase, with the liquid phase being condensate; the gas phase outlet of the separator S-3 is connected to the mixer M-1 and returns to the inlet of the compressor K-101; The decarbonization unit has a bottom outlet manifold of molecular sieve dryer D-1-A / B connected to the inlet of pressure swing adsorption system PSA-1-A~B; the top outlet of pressure swing adsorption system PSA-1-A~B is connected to compressor K-2, and desorbed gas flows out from the bottom outlet, separating high-concentration CO2. The recompression and precooling unit is connected in sequence to compressor K-2, cooler E-3, heat exchanger HX-1, and inlet of cryogenic separator S-4. Cryogenic separator S-4 separates gas and liquid phases. The liquid phase outlet is connected to mixer M-2 and top inlet of demethanizer T-1. The gas phase outlet of cryogenic separator S-4 is connected to the middle inlet of demethanizer T-1. The methane purification and light hydrocarbon recovery unit has its bottom outlet of the demethanizer T-1 connected in sequence to the cryogenic pressurization pump P-1 and the subcooler E-4, separating liquid methane and / or liquefied natural gas (LNG); the top outlet of the demethanizer T-1 is connected in sequence to the heat exchanger HX-2 and the inlet of the reflux tank V-2; the liquid phase outlet of the reflux tank V-2 is connected in sequence to the reflux pump P-2, the mixer M-2, and the top inlet of the demethanizer. The two-stage membrane helium extraction unit has its reflux tank V-2 gas phase outlet connected sequentially to heater H-2, primary membrane separator OP-1, and secondary membrane separator OP-2 inlet to extract crude helium; the residual gas outlet of primary membrane separator OP-1 is connected to mixer M-1 and returns to compressor K-1 inlet; the residual gas outlet of secondary membrane separator OP-2 is connected to primary membrane separator OP-1 inlet. The integrated purification unit has its permeate outlet of the secondary membrane separator OP-2 connected in sequence to the pressure swing adsorption system PSA-2-A~E and the inlet of the temperature swing adsorber TSA-1, separating out refined helium. The nitrogen expansion cycle refrigeration unit has compressor K-3 outlet connected in sequence to cooler E-5, heat exchanger HX-1 refrigerant channel, and expander EXP-1 inlet; expander EXP-1 outlet is connected in sequence to heat exchanger HX-2 refrigerant channel and heat exchanger HX-1 refrigerant channel inlet, and returns to compressor K-3 inlet, forming a closed loop cycle.
2. The integrated dehydrogenation process for coalbed methane helium extraction and co-production of high-purity methane and / or liquefied natural gas (LNG) according to claim 1, characterized in that: The heat exchanger HX-1 is provided with a first heat exchange channel, a second heat exchange channel, and a third heat exchange channel. The first heat exchange channel is connected to the compressor K-3 via a pipe at its beginning and to the heat exchanger HX-2 via a pipe at its end. The second heat exchange channel is connected to the expander EXP-1 via a pipe at its beginning and to the cooler E-5 via a pipe at its end. The cooler E-3 is connected to the first end of the third heat exchange channel via a pipe at its end and to the cryogenic separator S-4 via a pipe at its end.
3. The integrated dehydrogenation process for coalbed methane helium extraction and co-production of high-purity methane and / or liquefied natural gas (LNG) according to claim 2, characterized in that: The heat exchanger HX-2 is provided with a fourth heat exchange channel and a fifth heat exchange channel; The first end of the fourth heat exchange channel is connected to the end of the first heat exchange channel of heat exchanger HX-1 via a pipe, and the end of the fourth heat exchange channel is connected to the expander EXP-1 via a pipe; the first end of the fifth heat exchange channel is connected to the demethanizer T-1 via a pipe, and the end of the fifth heat exchange channel is connected to the reflux tank V-2 via a pipe.
4. The integrated dehydrogenation process for coalbed methane helium extraction and co-production of high-purity methane and / or liquefied natural gas (LNG) according to any one of claims 1-3, characterized in that: The process includes an integrated refrigeration system that employs a nitrogen expansion refrigeration cycle. The system utilizes heat exchangers HX-1 and HX-2 to provide cooling for the feed precooling and top condensation of the demethanizer T-1, achieving cascaded utilization and efficient integration of cooling capacity within the system and significantly reducing overall energy consumption.