Poly-generation system utilizing LNG (Liquefied Natural Gas) cold energy and oxygen-enriched combustion power generation circulation

Abstract

The invention discloses a poly-generation system utilizing LNG (Liquefied Natural Gas) cold energy and oxygen-enriched combustion power generation circulation, which is characterized in that an Alam circulation power generation subsystem is characterized in that a combustion chamber is configured to perform oxygen-enriched combustion on gasified LNG fuel and oxygen by-produced by a PEM water electrolysis hydrogen production subsystem, supercritical # imgabs0 # is used as a working medium to drive a turbine to generate power, and the power returns to a combustion front end to participate in circulation after doing work; the combustion increment is captured; according to the PEM water electrolysis hydrogen production subsystem, water is electrolyzed through an electrolytic tank to generate hydrogen and oxygen, the oxygen is supplied to a combustion chamber, and the hydrogen is supplied to the hydrogen liquefaction subsystem; the hydrogen liquefaction subsystem is used for liquefying hydrogen by utilizing cold energy in the LNG gasification process and collecting and storing the liquefied hydrogen; according to the ORC power generation subsystem, combustion waste heat of the Allam cycle power generation subsystem is used as a high-temperature heat source, cold energy in the LNG gasification process is used as a low-temperature heat source, and power is generated through organic Rankine cycle. And efficient and green co-production of electric energy and liquid hydrogen is at least achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of polygeneration, and particularly relates to a polygeneration system that utilizes the cold energy of LNG and an oxy-fuel combustion power generation cycle. Background Art

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

[0003] A large amount of cold energy is released during the gasification process of LNG. However, the existing technologies have problems of low efficiency and single use in the utilization of cold energy.

[0004] Although the electrolytic water hydrogen production technology can achieve the production of green hydrogen, its high energy consumption characteristics seriously restrict the economy, and the energy consumption during the hydrogen liquefaction process is huge. There is an urgent need for collaborative optimization of cold energy.

[0005] In the field of power generation, the Allam cycle of oxy-fuel combustion has attracted much attention due to the high efficiency of the supercritical working fluid and its carbon capture ability. However, the problems of its dependence on high-purity oxygen (requiring a high-energy-consuming air separation unit) and high equipment costs have not been solved.

[0006] Existing solutions mostly focus on the optimization of single functions, lacking a systematic design for the cascaded utilization of cold energy, resource recycling, and multi-product polygeneration, resulting in low energy utilization efficiency and insufficient economy. The purpose of the present invention is to break through the above bottlenecks and achieve efficient, low-carbon, and economic polygeneration through the deep coupling of multiple technologies and resource recycling design. Summary of the Invention

[0007] The purpose of the present invention is to provide a polygeneration system that utilizes the cold energy of LNG and an oxy-fuel combustion power generation cycle, and the technical problem to be solved is to make full use of the cold energy of LNG to achieve the efficient and green co-production of electric energy and liquid hydrogen.

[0008] To achieve the above purpose, the solution of the present invention is: a polygeneration system that utilizes the cold energy of LNG and an oxy-fuel combustion power generation cycle, including an Allam cycle power generation subsystem, a PEM electrolytic water hydrogen production subsystem, a hydrogen liquefaction subsystem, and an ORC power generation subsystem; Allam cycle power generation subsystem: including a combustion chamber, a turbine, and a carbon dioxide compression device. The combustion chamber is configured to receive the gasified LNG fuel and the oxygen by-produced by the PEM electrolytic water hydrogen production subsystem for oxy-fuel combustion, and use supercritical carbon dioxide as the working fluid to expand and do work to drive the turbine to generate electricity. After being compressed by the carbon dioxide compression device, it re-participates in the combustion cycle, and the increased carbon dioxide after combustion is captured; PEM electrolytic water hydrogen production subsystem: It includes an electrolytic cell that electrolyzes water to generate hydrogen and oxygen, where 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; Hydrogen liquefaction subsystem: Utilize the cold energy during the gasification of LNG to liquefy the hydrogen supplied by the PEM electrolytic water hydrogen production subsystem, and collect and store the liquefied hydrogen; ORC power generation subsystem: Use the combustion waste heat of the Allam cycle power generation subsystem as the high-temperature heat source, and use the cold energy during the gasification of LNG as the low-temperature heat source to generate electricity through the organic Rankine cycle.

[0009] Furthermore, the Allam cycle power generation subsystem also includes a regenerator. The high-temperature gas released after the turbine does 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 for heat exchange through the regenerator.

[0010] 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 the 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 the high-temperature heat source.

[0011] Furthermore, it also includes a carbon dioxide gas-water separator. The high-temperature gas discharged from the combustion chamber, after releasing heat through the ORC power generation subsystem, passes through the carbon dioxide gas-water separator to separate out water, and then enters the carbon dioxide compression device. The separated water is used to supply the PEM electrolytic water hydrogen production subsystem as electrolysis raw materials.

[0012] Furthermore, the hydrogen liquefaction subsystem includes an LNG heat exchanger and a hydrogen liquefaction turbine. The hydrogen supplied by the PEM electrolytic water hydrogen production subsystem first passes through the LNG heat exchanger to exchange 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 then undergoes cryogenic cooling through the hydrogen liquefaction turbine, and then the cryogenic liquid hydrogen is collected and stored.

[0013] Furthermore, the hydrogen liquefaction subsystem also includes a hydrogen gas-water separator and a hydrogen reflux heat exchanger. The cryogenic hydrogen enters the hydrogen gas-water separator to separate the gaseous hydrogen from the liquid hydrogen, and the separated gaseous hydrogen is refluxed to before the LNG heat exchanger to mix with the hydrogen supplied by the PEM electrolytic water hydrogen production subsystem and re-participate in the cycle. During the reflux process, the separated gaseous hydrogen sequentially passes through the hydrogen reflux heat exchanger and the LNG heat exchanger to exchange heat with the hydrogen flowing towards the hydrogen gas-water separator.

[0014] Further, the gaseous hydrogen separated from the hydrogen gas-water separator is compressed by a hydrogen compressor and then mixed with the hydrogen supplied by the PEM water electrolysis hydrogen production subsystem.

[0015] Further, the LNG cold energy is successively used as the low-temperature heat source for hydrogen liquefaction and ORC power generation, and is supplied to the combustion chamber after gasification.

[0016] Further, the combustion chamber also receives high-purity oxygen from an air separation unit to participate in oxygen-enriched combustion.

[0017] Further, in the Allam cycle power generation subsystem, the increased carbon dioxide after combustion is captured and stored.

[0018] After adopting the above scheme, the beneficial effects of the present invention are as follows: The Allam cycle power generation subsystem utilizes the oxygen by-produced by the PEM water electrolysis hydrogen production subsystem, uses gasified LNG as fuel, supercritical carbon dioxide as the circulating working fluid, and conducts oxygen-enriched combustion for 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 during the liquefaction process for efficient co-production of liquid hydrogen; then, the waste heat of the Allam cycle power generation subsystem is used as the heat source, the cold energy of LNG is used as the cold source, and power generation is carried out through the ORC power generation subsystem to efficiently utilize the remaining energy; thus, the subsystems are closely linked and cooperate with each other to at least achieve efficient and green co-production of electric energy and liquid hydrogen. Description of the Drawings

[0019] Figure 1 Schematic diagram of the system structure of the present invention.

[0020] Reference Numeral Description: 100 - Allam cycle power generation subsystem, 101 - combustion chamber, 102 - turbine, 103 - carbon dioxide compression device, 104 - recuperator, 105 - oxygen interface, 106 - natural gas compressor, 107 - oxygen-carbon dioxide compressor, 108 - carbon dioxide pump; 200 - PEM water electrolysis hydrogen production subsystem, 201 - electrolytic cell, 202 - water pump, 203 - oxygen gas-water separator; 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; 400 - ORC power generation subsystem, 401 - ORC pump, 402 - ORC evaporator, 403 - ORC turbine, 404 - ORC condenser, 405 - carbon dioxide gas-water separator. Detailed Description of the Invention

[0021] The following describes the present invention in detail with reference to the drawings and specific embodiments.

[0022] Embodiments of the present invention will be described comprehensively below with reference to the accompanying drawings. It should be noted that the present invention can be implemented in different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0023] The present invention provides a polygeneration system using LNG cold energy and oxy-fuel combustion power generation cycle, including an Allam cycle power generation subsystem 100, a PEM electrolytic water hydrogen production subsystem 200, a hydrogen liquefaction subsystem 300, and an ORC power generation subsystem 400; Allam cycle power generation subsystem 100: It includes a combustion chamber 101, a turbine 102, and a carbon dioxide compression device 103. The combustion chamber 101 is configured to receive the gasified LNG fuel and the oxygen by-produced by the PEM electrolytic water hydrogen production subsystem 200 for oxy-fuel combustion. To ensure sufficient oxygen supply, specifically in this embodiment, the combustion chamber 101 also receives high-purity oxygen from an air separation device (not shown in the drawings, which 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 the working fluid. The gasified natural gas is compressed by a natural gas compressor 106, and the oxygen and carbon dioxide are compressed by an oxygen-carbon dioxide compressor 107, and then enter the combustion chamber 101. The gasified natural gas undergoes oxy-fuel combustion with oxygen in the combustion chamber 101, causing the working fluid supercritical carbon dioxide to expand and do work to drive the turbine 102 (a machine that converts the energy contained in a fluid medium into mechanical work) to generate electricity. After the natural gas burns, water and carbon dioxide are generated. The working fluid carbon dioxide is compressed by the compression device 103 to the combustion pressure (the set pressure suitable for entering the combustion chamber 101 and the turbine 102), and then is pumped back to the combustion chamber and the turbine by a carbon dioxide pump 108 to participate in the cycle again. Preferably, it also passes through a recuperator 104 before entering the combustion chamber and the turbine. The function of the recuperator will be elaborated 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 for storage, enabling the system to produce high-pressure carbon dioxide. Of course, it is also necessary to separate the combustion products water and carbon dioxide before entering the carbon dioxide compression device 103, which will be elaborated later; PEM electrolysis hydrogen production subsystem 200: It includes an electrolytic cell 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 to the electrolytic cell 201 as the electrolysis raw material. The oxygen generated by the electrolysis of the electrolytic cell 201 is dehydrated by the oxygen gas-water separator 203 and then supplied to the Allam cycle power generation subsystem, and the separated water is re-circulated to the electrolytic cell 201 to make full use of water resources; Hydrogen liquefaction subsystem 300: Utilize the cold energy during the gasification process of LNG to liquefy the hydrogen supplied by the PEM electrolysis hydrogen production subsystem 200, and collect and store the liquefied hydrogen to achieve the production 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 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 to achieve pre-cooling of the hydrogen. The LNG heat exchanger 301 can be set in multiple stages. Specifically, two stages are set in this embodiment. The pre-cooled hydrogen then undergoes deep cooling through the hydrogen liquefaction turbine 302. The hydrogen liquefaction turbine 302 can also be set in multiple stages. It is three stages in this embodiment. Finally, the deep-cooled liquid hydrogen is collected and stored. More preferably, the hydrogen liquefaction subsystem 300 also includes a hydrogen gas-water separator 303 and a hydrogen reflux heat exchanger 304. The deep-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 before the LNG heat exchanger 301, compressed by a hydrogen compressor 305, and then mixed with the hydrogen supplied by the PEM electrolysis hydrogen production subsystem 200 to re-participate in the cycle. During the reflux process, the separated gaseous hydrogen sequentially passes through each hydrogen reflux heat exchanger 304 and each LNG heat exchanger 301 to exchange heat with the hydrogen flowing towards the hydrogen gas-water separator 303, and efficiently utilize the cold energy of the reflux hydrogen; ORC Power Generation System 400: Using the combustion waste heat of the Allam cycle power generation system 100 as a high-temperature heat source and the cold energy during the LNG gasification process as a low-temperature heat source, electricity is generated through an organic Rankine cycle. Specifically, the ORC power generation system 400 includes an ORC pump 401, an ORC evaporator 402, an ORC turbine 403, and an ORC condenser 404 that are connected in sequence to form a cycle (enabling the working fluid to circulate). LNG releases cold energy to the ORC power generation system 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 system 400 through the ORC evaporator 402 as a high-temperature heat source, thereby enabling the working fluid to do work and generate electricity through the ORC turbine 403, achieving the full utilization of the Allam cycle power generation system 100 and the cold energy during the LNG gasification process.

[0024] In a preferred embodiment, in order to achieve the cascaded utilization of energy during the LNG gasification process, the cold energy of LNG is sequentially used as the 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 is greater than the demand of the Allam cycle power generation system, the excess gasified natural gas is discharged and stored. Specifically, the externally supplied LNG (liquefied natural gas) is pumped into the system by an LNG pump 306, and sequentially passes through each LNG heat exchanger 301 and the ORC condenser to release cold energy while achieving gasification. The gasified natural gas (NG) after passing through the ORC condenser is split, a part flows to the combustion chamber 101, and the excess part is discharged and stored, realizing the output of gasified natural gas.

[0025] In a preferred embodiment, the Allam cycle power generation system 100 further includes a recuperator 104. The high-temperature gas (a mixture of water vapor and carbon dioxide) released after the turbine 102 does 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 recuperator 104 for heat exchange through the recuperator 104 to fully utilize the waste heat of the Allam cycle power generation system 100.

[0026] In a more specific embodiment, it further includes a carbon dioxide gas-water separator 405. After the high-temperature gas discharged from the combustion chamber 101 releases heat through the ORC evaporator 402 of the ORC power generation system, water is separated through the carbon dioxide gas-water separator 405 and then enters the carbon dioxide compression device 103. The separated water is used as electrolysis raw material for supply to the PEM electrolytic water hydrogen production subsystem 200, realizing the efficient self-supply utilization of water within the system.

[0027] Through the above structure, the efficient co-production of liquid hydrogen, gasified natural gas, high-pressure carbon dioxide, water, and electric energy is achieved.

[0028] The effects of the present invention will be described below in conjunction with a specific case: Taking a coastal area with an LNG receiving terminal, equipped with wind power generation, and having a certain proportion of curtailed wind as an example, first, a thermodynamic simulation model of the Allam cycle power generation subsystem, PEM electrolysis hydrogen production subsystem, hydrogen liquefaction subsystem, and ORC power generation subsystem is established; secondly, the thermodynamic performance simulation of the polygeneration system of the present invention is carried out, and the energy comprehensive utilization efficiency, exergy efficiency, and primary energy savings rate are selected as indicators to evaluate its performance, study the system performance characteristics under the design conditions, and quantify the advantages of the polygeneration system in terms of energy conservation and environmental benefits.

[0029] The thermodynamic performance of the polygeneration system proposed by the present invention is shown in Table 1: Table 1 Thermodynamic Performance of the Polygeneration System

[0030] As can be seen from the calculation results of the thermodynamic performance in Table 1, while the polygeneration system absorbs 200 MW of renewable power and 25 kg / s of LNG cold energy, 15 kg / s of LNG, 11.04 kg / s of oxygen from PEM, and 51.8 kg / s of oxygen from ASU are used for combustion power generation, and 384.17 MW of stable power, 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) can be produced, and the gasification of LNG (30 bar, 25 °C) is achieved. In terms of power output, the Allam cycle provides 631.10 MW of electric power, the cold energy ORC provides 1.32 MW of electric power, the total power consumption of the system is 225.96 MW, of which 23.63% of the power loss comes from the hydrogen liquefaction process, and 87.01% of the power consumption comes from the Allam cycle itself. In the Allam cycle, the maximum power consumption mainly comes from the pressure boost process after the cycle working fluid does work and the air separation device. Overall, the energy comprehensive utilization efficiency and exergy efficiency of the polygeneration system are 85.52% and 63.34% respectively, the specific energy consumption of the hydrogen liquefaction process is 9.43 kWh / kgH2, and the liquefaction rate is 16.28%.

[0031] The above is only the preferred embodiment of the present invention, and it does not limit the design of this case. All equivalent changes made according to the key design of this case fall within the protection scope of this case.

Claims

1. A polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle, characterized in that: 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); The 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 byproduct 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 perform work to drive the turbine (102) to generate electricity, and then re-participate in the combustion cycle after being compressed by the carbon dioxide compression device (103); The PEM water electrolysis hydrogen production subsystem (200) comprises 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 waste heat from combustion 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. A polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in 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. A 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) comprises 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. LNG releases cold energy to the ORC power generation subsystem (400) via the ORC condenser (404) as a low-temperature heat source, and high-temperature gas discharged from the combustion chamber (101) releases heat energy to the ORC power generation subsystem (400) via the ORC evaporator (402) as a high-temperature heat source.

4. A polygeneration system utilizing LNG cold energy and 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. A 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) comprises 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 oxygen-enriched combustion power generation cycle as claimed in claim 5, characterized in that: The hydrogen liquefaction subsystem (300) further comprises a hydrogen gas-water separator (303) and a hydrogen reflux heat exchanger (304). The deep-cooled hydrogen enters the hydrogen gas-water separator (303) to separate gaseous hydrogen from 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 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. A polygeneration system utilizing LNG cold energy and oxygen-enriched combustion power generation cycle as claimed in claim 1, characterized in that: 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 (101) after gasification.

9. A 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. A 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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