A polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle

Abstract

The present invention discloses a polygeneration system utilizing LNG cold energy and an oxygen-enriched combustion power generation cycle. The Allam cycle power generation subsystem comprises a combustion chamber configured to perform oxygen-enriched combustion of vaporized LNG fuel and oxygen produced as a byproduct of the PEM water electrolysis hydrogen production subsystem. Supercritical CO2 gas (supercritical CO2) serves as the working fluid, driving a turbine to generate electricity. After generating work, the supercritical CO2 gas returns to the combustion front and participates in the cycle, where the combustion increment is captured. The PEM water electrolysis hydrogen production subsystem employs an electrolyzer that electrolyzes water to generate hydrogen and oxygen. The oxygen is supplied to the combustion chamber, and the hydrogen is supplied to the hydrogen liquefaction subsystem. The hydrogen liquefaction subsystem utilizes cold energy from the LNG vaporization process to liquefy hydrogen, which is then collected and stored. The ORC power generation subsystem utilizes the waste heat from the Allam cycle power generation subsystem as a high-temperature heat source and the cold energy from the LNG vaporization process as a low-temperature heat source, generating electricity via an organic Rankine cycle. This system achieves efficient and green cogeneration of at least electricity and liquid hydrogen.

Description

Technical Field

[0001] The present invention relates to the technical field of polygeneration, and in particular to a polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle. Background Art

[0002] With the advancement of energy structure transformation and carbon neutrality goals, liquefied natural gas (LNG) cold energy recovery, hydrogen energy production and low-carbon power generation technologies have become research hotspots.

[0003] LNG releases a large amount of cold energy during the gasification process, but the existing technology for utilizing cold energy has problems of low efficiency and single use.

[0004] Although water electrolysis hydrogen production technology can achieve green hydrogen production, its high energy consumption characteristics seriously restrict its economic feasibility, and the hydrogen liquefaction process consumes huge energy, and urgently needs the coordinated optimization of cold energy.

[0005] In the field of power generation, the Allam cycle of oxygen-enriched combustion is The efficiency and carbon capture capacity of the working fluid have attracted much attention, but its dependence on high-purity oxygen (which requires high-energy air separation equipment) and high equipment costs remain unresolved.

[0006] Existing solutions mostly focus on single-function optimization and lack system design for cascade utilization of cold energy, resource recycling, and multi-product co-production, resulting in low energy utilization and insufficient economy. The present invention aims to break through the above bottlenecks through deep coupling of multiple technologies and resource recycling design to achieve efficient, low-carbon, and economical multi-product co-production. Summary of the Invention

[0007] The purpose of the present invention is to provide a polygeneration system that utilizes LNG cold energy and oxygen-enriched combustion power generation cycle, and to solve the technical problem of fully utilizing LNG cold energy to achieve efficient and green cogeneration of electricity and liquid hydrogen.

[0008] To achieve the above objectives, the solution of the present invention is: a polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle, comprising an Allam cycle power generation subsystem, a PEM water electrolysis hydrogen production subsystem, a hydrogen liquefaction subsystem, and an ORC power generation subsystem;

[0009] The Allam cycle power generation subsystem includes a combustion chamber, a turbine, and a carbon dioxide compression device. The combustion chamber is configured to receive gasified LNG fuel and oxygen produced as a byproduct of the PEM water electrolysis hydrogen production subsystem for oxygen-enriched combustion. The supercritical carbon dioxide is used as the working fluid, which expands and generates work to drive the turbine to generate electricity. After being compressed by the carbon dioxide compression device, it re-enters the combustion cycle, and the incremental carbon dioxide after combustion is captured.

[0010] PEM water electrolysis hydrogen production subsystem: includes an electrolyzer, which electrolyzes water to generate hydrogen and oxygen, wherein the oxygen is supplied to the combustion chamber of the Allam cycle power generation subsystem, and the hydrogen is supplied to the hydrogen liquefaction subsystem;

[0011] Hydrogen liquefaction subsystem: Utilizes the cold energy from the LNG gasification process to liquefy the hydrogen supplied by the PEM water electrolysis hydrogen production subsystem, and collects and stores the liquefied hydrogen;

[0012] ORC power generation subsystem: Utilizes the waste heat from combustion in the Allam cycle power generation subsystem as a high-temperature heat source, and utilizes the cold energy from the LNG gasification process as a low-temperature heat source to generate electricity through an organic Rankine cycle.

[0013] Furthermore, the Allam cycle power generation subsystem also includes a regenerator, and the high-temperature gas released after the turbine performs work, the low-temperature carbon dioxide before entering the combustion chamber and the turbine, and the low-temperature oxygen before entering the combustion chamber all pass through the regenerator to perform heat exchange.

[0014] Furthermore, the ORC power generation subsystem includes an ORC pump, an ORC evaporator, an ORC turbine and an ORC condenser connected in sequence to form a cycle. LNG releases cold energy to the ORC power generation subsystem through the ORC condenser as a low-temperature heat source, and the high-temperature gas discharged from the combustion chamber releases heat energy to the ORC power generation subsystem through the ORC evaporator as a high-temperature heat source.

[0015] Furthermore, it also includes a carbon dioxide gas-water separator. After the high-temperature gas discharged from the combustion chamber releases heat through the ORC power generation subsystem, it passes through the carbon dioxide gas-water separator to separate water and then enters the carbon dioxide compression device. The separated water is used to supply the PEM water electrolysis hydrogen production subsystem as electrolysis raw material.

[0016] Furthermore, the hydrogen liquefaction subsystem includes an LNG heat exchanger and a hydrogen liquefaction turbine. The hydrogen supplied by the PEM water electrolysis hydrogen production subsystem first passes through the LNG heat exchanger and exchanges heat with the LNG before being supplied to the Allam cycle power generation subsystem to achieve pre-cooling of the hydrogen. The pre-cooled hydrogen is then deep-cooled by the hydrogen liquefaction turbine, and the deep-cooled liquid hydrogen is then collected and stored.

[0017] Furthermore, the hydrogen liquefaction subsystem also includes a hydrogen gas-water separator and a hydrogen reflux heat exchanger. The deep-cooled hydrogen enters the hydrogen gas-water separator to separate the gaseous hydrogen from the liquid hydrogen. The separated gaseous hydrogen is refluxed to the front of the LNG heat exchanger, mixed with the hydrogen supplied from the PEM water electrolysis hydrogen production subsystem, and re-circulated. During the reflux process, the separated gaseous hydrogen passes through the hydrogen reflux heat exchanger and the LNG heat exchanger in turn to exchange heat with the hydrogen flowing to the hydrogen gas-water separator.

[0018] Furthermore, the gaseous hydrogen separated from the hydrogen gas-water separator is compressed by the hydrogen compressor and then mixed with the hydrogen supplied by the PEM water electrolysis hydrogen production subsystem.

[0019] Furthermore, the cold energy of LNG is used in turn as a low-temperature heat source for hydrogen liquefaction and ORC power generation, and is supplied to the combustion chamber after gasification.

[0020] Furthermore, the combustion chamber also receives high-purity oxygen from an air separation unit to participate in oxygen-enriched combustion.

[0021] Furthermore, in the Allam cycle power generation system, the incremental carbon dioxide after combustion is captured and stored.

[0022] After adopting the above scheme, the beneficial effects of the present invention are: the Allam cycle power generation subsystem utilizes the oxygen produced as a by-product of the PEM water electrolysis hydrogen production subsystem, uses the gasified LNG as fuel, and supercritical carbon dioxide as the circulating working fluid, and performs oxygen-enriched combustion to perform green power generation; at the same time, the hydrogen mainly produced by the PEM water electrolysis hydrogen production subsystem utilizes the cold energy of LNG in the liquefaction process to carry out efficient co-production of liquid hydrogen; then, the waste heat of the Allam cycle power generation subsystem is utilized as a heat source, and the cold energy of LNG is utilized as a cold source to generate electricity through the ORC power generation subsystem, and the remaining energy is efficiently utilized; thus, the subsystems are linked together and cooperate with each other to at least achieve efficient and green co-production of electricity and liquid hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the system structure of the present invention.

[0024] Description of labels:

[0025] 100-Allam cycle power generation subsystem, 101-combustion chamber, 102-turbine, 103-CO2 compression device, 104-regenerator, 105-oxygen interface, 106-natural gas compressor, 107-oxygen CO2 compressor, 108-CO2 pump;

[0026] 200-PEM water electrolysis hydrogen production subsystem, 201-electrolyzer, 202-water pump, 203-oxygen gas-water separator;

[0027] 300-Hydrogen liquefaction subsystem, 301-LNG heat exchanger, 302-Hydrogen liquefaction turbine, 303-Hydrogen gas-water separator, 304-Hydrogen reflux heat exchanger, 305-Hydrogen compressor, 306-LNG pump;

[0028] 400-ORC generator subsystem, 401-ORC pump, 402-ORC evaporator, 403-ORC turbine, 404-ORC condenser, 405-CO2 gas-water separator. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The following is a comprehensive description of embodiments of the present invention with reference to the accompanying drawings. It should be noted that the present invention may be embodied in various forms and is not limited to the embodiments described herein. These embodiments are provided to make this disclosure thorough and complete and to fully convey the scope of the invention to those skilled in the art.

[0031] The present invention provides a polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle, comprising an Allam cycle power generation subsystem 100, a PEM water electrolysis hydrogen production subsystem 200, a hydrogen liquefaction subsystem 300, and an ORC power generation subsystem 400;

[0032] Allam cycle power generation subsystem 100: includes a combustion chamber 101, a turbine 102 and a carbon dioxide compression device 103, wherein the combustion chamber 101 is configured to receive gasified LNG fuel and oxygen produced as a by-product of the PEM water electrolysis hydrogen production subsystem 200 for oxygen-enriched combustion. To ensure sufficient oxygen supply, specifically in this embodiment, the combustion chamber 101 also receives high-purity oxygen from an air separation device. The air separation device is not shown in the accompanying drawings and is any existing device capable of separating oxygen from air. The oxygen outlet of the air separation device is connected to the oxygen interface 105. The Allam cycle power generation subsystem 100 uses supercritical carbon dioxide as a working fluid. The gasified natural gas is compressed by a natural gas compressor 106, and oxygen and carbon dioxide are compressed by an oxygen and carbon dioxide compressor 107, and then enter the combustion chamber 101. The gasified natural gas is reacted with oxygen in the combustion chamber 101. Oxygen-rich combustion causes the supercritical carbon dioxide of the working medium to expand and work to drive the turbine 102 (a machine that converts the energy contained in the fluid medium into mechanical work) to generate electricity. After the natural gas is burned, water and carbon dioxide are generated. The working medium carbon dioxide is compressed to the combustion pressure (the pressure set to be suitable for entering the combustion chamber 101 and the turbine 102) by the compression device 103, and then pumped back to the combustion chamber and the turbine by the carbon dioxide pump 108 to participate in the cycle again. Preferably, it also passes through the regenerator 104 before entering the combustion chamber and the turbine. The role of the regenerator will be explained in detail later. Specifically, since a certain amount of carbon dioxide is generated during each combustion, it is compressed into high-pressure carbon dioxide by the carbon dioxide compression device 103 and then discharged and stored, so that the system can achieve the output of high-pressure carbon dioxide. Of course, the combustion products water and carbon dioxide also need to be separated before entering the carbon dioxide compression device 103, which will be explained in detail later.

[0033] The PEM water electrolysis hydrogen production subsystem 200 includes an electrolyzer 201, which electrolyzes water to generate hydrogen and oxygen. The oxygen is supplied to the combustion chamber 101 of the Allam cycle power generation subsystem 100, and the hydrogen is supplied to the hydrogen liquefaction subsystem 300. More specifically, it also includes a water pump 202 and an oxygen gas-water separator 203. The water pump 202 is used to pump water as an electrolysis raw material to the electrolyzer 201. The oxygen generated by electrolysis in the electrolyzer 201 is dehydrated by the oxygen gas-water separator 203 and then supplied to the Allam cycle power generation subsystem. The dehydrated water is then returned to the electrolyzer 201 to fully utilize water resources.

[0034] Hydrogen liquefaction subsystem 300: Utilizes the cold energy in the LNG gasification process to liquefy the hydrogen supplied by the PEM water electrolysis hydrogen production subsystem 200, and collects and stores the liquefied hydrogen to achieve the output of liquid hydrogen; In a preferred specific embodiment, the hydrogen liquefaction subsystem 300 includes an LNG heat exchanger 301 and a hydrogen liquefaction turbine 302. The hydrogen supplied by the PEM water electrolysis hydrogen production subsystem 200 first passes through the LNG heat exchanger 301 and exchanges heat with the LNG before being supplied to the Allam cycle power generation subsystem 100 to achieve pre-cooling of the hydrogen. The LNG heat exchanger 301 can be set to multiple stages, specifically two stages in this embodiment. The pre-cooled hydrogen is then deep-cooled through the hydrogen liquefaction turbine 302. The hydrogen liquefaction turbine 302 can also be set to multiple stages, three stages in this embodiment, and finally the deep-cooled liquid hydrogen is collected and stored. More preferably, the hydrogen liquefaction subsystem 300 further includes a hydrogen gas-water separator 303 and a hydrogen reflux heat exchanger 304. The cryogenically cooled hydrogen enters the hydrogen gas-water separator 303 to separate the gaseous hydrogen from the liquid hydrogen. The separated gaseous hydrogen is refluxed to the LNG heat exchanger 301, compressed by the hydrogen compressor 305, and then mixed with the hydrogen supplied from the PEM water electrolysis hydrogen production subsystem 200 to recirculate. During the reflux process, the separated gaseous hydrogen passes through each hydrogen reflux heat exchanger 304 and each LNG heat exchanger 301 in sequence to exchange heat with the hydrogen flowing to the hydrogen gas-water separator 303, thereby efficiently utilizing the cold energy of the reflux hydrogen.

[0035] ORC power generation subsystem 400: utilizes the waste heat from combustion of the Allam cycle power generation subsystem 100 as a high-temperature heat source and utilizes the cold energy during the LNG vaporization process as a low-temperature heat source to generate electricity through an organic Rankine cycle. Specifically, the ORC power generation subsystem 400 includes an ORC pump 401, an ORC evaporator 402, an ORC turbine 403, and an ORC condenser 404, which are sequentially connected to form a cycle (enabling the working fluid to circulate). LNG releases cold energy to the ORC power generation subsystem 400 through the ORC condenser 404 as a low-temperature heat source. The high-temperature gas (a mixture of water vapor and carbon dioxide) discharged from the combustion chamber 101 releases heat energy to the ORC power generation subsystem 400 through the ORC evaporator 402 as a high-temperature heat source, thereby enabling the working fluid to generate electricity through the ORC turbine 403, thereby fully utilizing the Allam cycle power generation subsystem 100 and the cold energy during the LNG vaporization process.

[0036] In a preferred embodiment, in order to achieve cascaded energy utilization in the LNG gasification process, LNG cold energy is sequentially used as a low-temperature heat source for hydrogen liquefaction and ORC power generation, and is supplied to the combustion chamber 101 after gasification. When the amount of gasified natural gas exceeds the demand of the Allam cycle power generation subsystem, the excess gasified natural gas is discharged and stored. Specifically, LNG (liquefied natural gas) supplied from the outside is pumped into the system through the LNG pump 306, passes through each LNG heat exchanger 301 and the ORC condenser in sequence to release cold energy and achieve gasification at the same time. The gasified natural gas (NG) after passing through the ORC condenser is split, with a portion flowing to the combustion chamber 101 and the excess portion discharged and stored, thereby achieving the output of gasified natural gas.

[0037] In a preferred embodiment, the Allam cycle power generation subsystem 100 further includes a regenerator 104. The high-temperature gas (a mixture of water vapor and carbon dioxide) released after the turbine 102 performs work, the low-temperature carbon dioxide before entering the combustion chamber 101 and the turbine 102, and the low-temperature oxygen before entering the combustion chamber 101 all pass through the regenerator 104 to perform heat exchange, thereby fully utilizing the waste heat of the Allam cycle power generation subsystem 100.

[0038] In a more specific embodiment, a carbon dioxide gas-water separator 405 is further included. After the high-temperature gas discharged from the combustion chamber 101 releases heat through the ORC evaporator 402 of the ORC power generation subsystem, it passes through the carbon dioxide gas-water separator 405 to separate water, and then enters the carbon dioxide compression device 103. The separated water is used to supply the PEM water electrolysis hydrogen production subsystem 200 as an electrolysis raw material, thereby realizing efficient self-sufficient utilization of water in the system.

[0039] Through the above structure, efficient multi-generation of liquid hydrogen, gasified natural gas, high-pressure carbon dioxide, water and electricity is achieved.

[0040] The following is a specific case to illustrate the effects of the present invention:

[0041] Taking a coastal area with an LNG receiving station, equipped with wind power generation, and a certain proportion of wind power curtailment as an example, a thermodynamic simulation model of the Allam cycle power generation subsystem, PEM water electrolysis hydrogen production subsystem, hydrogen liquefaction subsystem, and ORC power generation subsystem was first established. Secondly, the thermodynamic performance of the polygeneration system of the present invention was simulated, and its performance was evaluated by selecting comprehensive energy utilization efficiency, exergy efficiency, and primary energy saving rate as indicators. The system performance characteristics under the designed operating conditions were studied, and the advantages of the polygeneration system in energy conservation and environmental benefits were quantified.

[0042] The thermodynamic performance of the polygeneration system proposed in the present invention is shown in Table 1:

[0043] Table 1 Thermodynamic performance of polygeneration system

[0044]

[0045] Thermodynamic performance calculation results are shown in Table 1. This polygeneration system consumes 200 MW of renewable electricity and 25 kg / s of LNG cooling energy while combusting 15 kg / s of LNG, 11.04 kg / s of oxygen from the PEM, and 51.8 kg / s of oxygen from the ASU for power generation. This system can produce 384.17 MW of stable electricity, 1.39 kg / s of liquid hydrogen (1.4 bar, -251°C), 17.59 kg / s of medium-pressure water (30 bar, 25°C), and 44.87 kg / s of high-pressure carbon dioxide (120 bar, 25°C), while also vaporizing the LNG (30 bar, 25°C). In terms of power output, the Allam cycle provided 631.10 MW of electricity, and the cold energy ORC provided 1.32 MW of electricity, for a total system power consumption of 225.96 MW. Of this, 23.63% of power losses were due to the hydrogen liquefaction process, and 87.01% of power consumption was due to the Allam cycle itself. In the Allam cycle, the greatest power consumption comes primarily from the pressurization process after the circulating fluid performs work and from the air separation unit. Overall, the polygeneration system's comprehensive energy utilization efficiency and exergy efficiency were 85.52% and 63.34%, respectively. The specific energy consumption of the hydrogen liquefaction process was 9.43 kWh / kgH2, and the liquefaction rate was 16.28%.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the design of this case. Any equivalent changes made based on the key design of this case shall fall within the scope of protection of this case.

Claims

1. A polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle, characterized by: It includes an Allam cycle power generation subsystem (100), a PEM water electrolysis hydrogen production subsystem (200), a hydrogen liquefaction subsystem (300), and an ORC power generation subsystem (400); An Allam cycle power generation subsystem (100) comprises a combustion chamber (101), a turbine (102) and a carbon dioxide compression device (103), wherein the combustion chamber (101) is configured to receive gasified LNG fuel and oxygen produced as a by-product of the PEM water electrolysis hydrogen production subsystem (200) for oxygen-enriched combustion, and to use supercritical carbon dioxide as a working fluid to expand and generate power by driving the turbine (102), which is then compressed by the carbon dioxide compression device (103) and re-enters the combustion cycle; PEM water electrolysis hydrogen production subsystem (200): comprising an electrolyzer (201), wherein the electrolyzer (201) electrolyzes water to generate hydrogen and oxygen, wherein the oxygen is supplied to the combustion chamber (101) of the Allam cycle power generation subsystem (100), and the hydrogen is supplied to the hydrogen liquefaction subsystem (300); The hydrogen liquefaction subsystem (300) utilizes the cold energy in the LNG gasification process to liquefy the hydrogen supplied by the PEM water electrolysis hydrogen production subsystem (200), and collects and stores the liquefied hydrogen; ORC power generation subsystem (400): utilizes the combustion waste heat of the Allam cycle power generation subsystem (100) as a high-temperature heat source, utilizes the cold energy in the LNG gasification process as a low-temperature heat source, and generates electricity through an organic Rankine cycle.

2. The polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle according to claim 1, characterized in that: The Allam cycle power generation subsystem (100) further includes a regenerator (104), wherein high-temperature gas released after the turbine (102) performs work, low-temperature carbon dioxide before entering the combustion chamber (101) and the turbine (102), and low-temperature oxygen before entering the combustion chamber (101) all pass through the regenerator (104) to perform heat exchange.

3. The polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in claim 1, characterized in that: The ORC power generation subsystem (400) includes an ORC pump (401), an ORC evaporator (402), an ORC turbine (403), and an ORC condenser (404) that are sequentially connected to form a circulation. LNG releases cold energy to the ORC power generation subsystem (400) through the ORC condenser (404) as a low-temperature heat source. High-temperature gas discharged from the combustion chamber (101) releases heat energy to the ORC power generation subsystem (400) through the ORC evaporator (402) as a high-temperature heat source.

4. A polygeneration system utilizing LNG cold energy and an oxygen-enriched combustion power generation cycle as claimed in claim 3, characterized in that: It also includes a carbon dioxide gas-water separator (405). After the high-temperature gas discharged from the combustion chamber (101) releases heat through the ORC power generation subsystem, it passes through the carbon dioxide gas-water separator (405) to separate water, and then enters the carbon dioxide compression device (103). The separated water is used to supply the PEM water electrolysis hydrogen production subsystem (200) as an electrolysis raw material.

5. The polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in claim 1, characterized in that: The hydrogen liquefaction subsystem (300) includes an LNG heat exchanger (301) and a hydrogen liquefaction turbine (302). The hydrogen supplied by the PEM water electrolysis hydrogen production subsystem (200) first passes through the LNG heat exchanger (301) to exchange heat with the LNG before being supplied to the Allam cycle power generation subsystem (100), thereby achieving pre-cooling of the hydrogen. The pre-cooled hydrogen is then deep-cooled by the hydrogen liquefaction turbine (302), and the deep-cooled liquid hydrogen is then collected and stored.

6. A polygeneration system utilizing LNG cold energy and an oxygen-enriched combustion power generation cycle as claimed in claim 5, characterized in that: The hydrogen liquefaction subsystem (300) further includes a hydrogen gas-water separator (303) and a hydrogen reflux heat exchanger (304). The cryogenically cooled hydrogen enters the hydrogen gas-water separator (303) to separate the gaseous hydrogen from the liquid hydrogen. The separated gaseous hydrogen is refluxed to the front of the LNG heat exchanger (301) to be mixed with the hydrogen supplied from the PEM water electrolysis hydrogen production subsystem (200) and to participate in the circulation again. In the reflux process, the separated gaseous hydrogen passes through the hydrogen reflux heat exchanger (304) and the LNG heat exchanger (301) in sequence to exchange heat with the hydrogen flowing to the hydrogen gas-water separator (303).

7. A polygeneration system utilizing LNG cold energy and an oxygen-enriched combustion power generation cycle as claimed in claim 6, characterized in that: The gaseous hydrogen separated from the hydrogen gas-water separator (303) is compressed by the hydrogen compressor (305) and then mixed with the hydrogen supplied by the PEM water electrolysis hydrogen production subsystem (200).

8. The polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in claim 1, characterized in that: The LNG cold energy is used in turn as a low-temperature heat source for hydrogen liquefaction and ORC power generation, and is supplied to the combustion chamber (101) after gasification.

9. The polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in claim 1, characterized in that: The combustion chamber (101) also receives high-purity oxygen from an air separation unit to participate in oxygen-enriched combustion.

10. The polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in claim 1, characterized in that: In the Allam cycle power generation subsystem (100), a predetermined amount of carbon dioxide is used as a working fluid to participate in the cycle, and the incremental carbon dioxide after combustion is captured and stored.

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