Coal gasification pure oxygen combustion power generation system

Abstract

The invention provides a coal gasification pure oxygen combustion power generation system, which relates to the technical field of oxygen-enriched combustion supercritical carbon dioxide power cycle power generation, and comprises a gasification furnace, a steam generator, a hydrogen separator, a combustion chamber and a turbine, a synthesis gas outlet of the gasification furnace is communicated with the combustion chamber through a high-temperature pipeline of the high-temperature synthesis gas regenerator, a high-temperature pipeline of the low-temperature synthesis gas regenerator, the first cooler and the hydrogen separator in sequence; an exhaust port of the turbine is communicated with the second cooler through a high-temperature pipeline of the high-temperature flue gas regenerator and a high-temperature pipeline of the low-temperature flue gas regenerator in sequence, and an exhaust port of the second cooler is communicated with a low-temperature pipeline exhaust port of the low-temperature flue gas regenerator and an exhaust port of the gasification furnace. A low-temperature pipeline exhaust port of the high-temperature synthesis gas regenerator is communicated with the gasification furnace and the combustion chamber; water vapor and carbon dioxide are introduced into the gasification furnace to participate in gasification, flexibility of water gasification and high efficiency of carbon dioxide gasification are both considered, and heat in the system is fully utilized.

Description

Technical Field

[0001] The invention relates to the technical field of oxygen-enriched combustion supercritical carbon dioxide power cycle power generation, and in particular to a coal gasification pure oxygen combustion power generation system. Background Art

[0002] Coal has an irreplaceable fundamental position in the energy structure and is an important guarantee for energy security. Coal-fired power generation is the most representative industry of coal utilization in my country, accounting for more than half of the total coal consumption. It is the main power source for my country's electricity supply and the main source of greenhouse gases such as carbon dioxide. Coal-fired power generation will continue to play an important role in ensuring my country's energy and power security and flexible peak regulation for a considerable period of time. Against this background, future coal-fired power generation will not only develop towards high efficiency, cleanliness and low carbonization, but also towards safety, flexibility and multi-functional transformation. Traditional coal-fired power plants are often difficult to achieve high efficiency, low carbonization and flexibility due to factors such as combustion, heat and mass transfer, and working fluid properties.

[0003] The supercritical carbon dioxide power cycle with direct heating by oxygen-enriched combustion is considered to be a very promising technical means for efficient zero-emission power generation of carbon-based fuels. In this power cycle, carbon-containing fuels burn with oxygen to directly heat high-pressure supercritical carbon dioxide, and the high-temperature and high-pressure flue gas produced enters the turbine to generate power. Since the operating fluid and combustion products of this cycle are both carbon dioxide, the carbon dioxide produced by combustion can be easily separated from the turbine exhaust without the need for complex carbon capture equipment; at the same time, the low power consumption of supercritical carbon dioxide near the critical point and the use of heat recovery methods can achieve efficient power generation.

[0004] The fuel for the oxygen-enriched combustion supercritical CO2 power cycle is generally natural gas. At the same time, solid fuels such as coal can also be converted into gas fuels to drive the cycle through gasification. The gasification medium for coal gasification can be selected from water vapor or CO2. The synthesis gas produced by CO2 gasification has a low H2 content, low moisture content after combustion, and less heat waste caused by the latent heat of water vaporization; however, CO2 comes from inside the unit, and when the load changes, the circulating CO2 has no time to change, which may cause a mismatch in the CO2 supply of the gasifier; the H2 content produced by water vapor gasification is high, and there is a lot of moisture after combustion, which leads to a lot of heat waste. At the same time, high-moisture flue gas is not conducive to the operation of key equipment such as turbines and regenerators; but the water input comes from the outside and can be adjusted in real time with load changes.

[0005] In the gasification combined with oxy-fuel combustion scheme, since the syngas needs to be purified (dehydrated and desulfurized) at a relatively low temperature and heat recovery of the syngas is required, the traditional heat recovery scheme fails to utilize the large amount of heat carried by the syngas at the outlet of the gasifier in a cascaded and efficient manner, resulting in some heat loss and a decrease in the overall efficiency. In addition, to ensure high gasification efficiency, the gasification temperature is relatively high, and the syngas needs to be quenched before heat exchange. The traditional scheme uses the purified syngas after cooling for quenching, leading to a large difference in the flow rates of the cold and hot streams during the heat recovery process of the syngas, making it difficult to reduce the temperature of the raw syngas and further increasing the heat loss. Summary of the Invention

[0006] The object of the present invention is to provide a gasification oxy-fuel combustion power generation system to solve the problems existing in the above-mentioned prior art, introduce steam and carbon dioxide into the gasifier to participate in gasification, taking into account the flexibility of water gasification and the high efficiency of carbon dioxide gasification, and making full use of the heat in the system.

[0007] To achieve the above object, the present invention provides the following solution:

[0008] A gasification oxy-fuel combustion power generation system includes a gasifier, a steam generator, a hydrogen separator, a combustion chamber, and a turbine; the gasifier is used for gasifying coal to generate syngas, the steam generator is used to supply gasification steam to the gasifier; the hydrogen separator is used to separate hydrogen from the syngas; the combustion chamber is used for burning the syngas; the intake port of the turbine is connected to the exhaust port of the combustion chamber and is used to drive a generator to generate electricity using the high-temperature flue gas of the combustion chamber; the syngas outlet of the gasifier is sequentially connected to the syngas intake port of the hydrogen separator through the high-temperature pipeline of the high-temperature syngas recuperator, the high-temperature pipeline of the low-temperature syngas recuperator, and a first cooler; the first hydrogen exhaust port of the hydrogen separator is used to connect to a hydrogen capture device; the syngas exhaust port of the hydrogen separator is sequentially connected to the combustion chamber through a second multi-stage intercooling compressor and the low-temperature pipeline of the low-temperature syngas recuperator; the exhaust port of the turbine is sequentially connected to a second cooler through the high-temperature pipeline of the high-temperature flue gas recuperator and the high-temperature pipeline of the low-temperature flue gas recuperator; the exhaust port of the second cooler is connected to a third multi-stage intercooling compressor and a fourth multi-stage intercooling compressor arranged in parallel; the exhaust port of the third multi-stage intercooling compressor is connected to a carbon dioxide capture device and the low-temperature pipeline of the low-temperature flue gas recuperator in parallel; the exhaust port of the low-temperature pipeline of the low-temperature flue gas recuperator is connected to the intake port of the low-temperature pipeline of the high-temperature syngas recuperator through the low-temperature pipeline of the high-temperature flue gas recuperator; the exhaust port of the low-temperature pipeline of the high-temperature syngas recuperator is connected to the gasifier and the combustion chamber; the exhaust port of the fourth multi-stage intercooling compressor is connected to the exhaust port of the gasifier.

[0009] As an embodiment, it further includes an electrolytic water device, and the second hydrogen exhaust port of the electrolytic water device is used to communicate with a hydrogen capture device; the oxygen exhaust port of the electrolytic water device is communicated with the gasifier and the combustion chamber.

[0010] As an embodiment, it further includes a hydrogen capture device, and the second hydrogen exhaust port is communicated with the first hydrogen exhaust port through a seventh intercooled compressor and is communicated with the hydrogen capture device through a first multi-stage intercooled compressor.

[0011] As an embodiment, it further includes a fifth multi-stage intercooled compressor, the intake port of the fifth multi-stage intercooled compressor is communicated with the oxygen exhaust port, and the exhaust port of the fifth multi-stage intercooled compressor is communicated with the gasifier and the combustion chamber.

[0012] As an embodiment, it further includes a sixth multi-stage intercooled compressor, the intake port of the sixth multi-stage intercooled compressor is communicated with the exhaust port of the fifth multi-stage intercooled compressor, and the exhaust port of the sixth multi-stage intercooled compressor is communicated with the combustion chamber.

[0013] As an embodiment, it further includes an adiabatic compressor, the intake port of the adiabatic compressor is communicated with the exhaust port of the second cooler, and the exhaust port of the adiabatic compressor is communicated with the exhaust port of the low-temperature pipeline of the low-temperature flue gas regenerator and the intake port of the low-temperature pipeline of the high-temperature flue gas regenerator through a three-way joint.

[0014] As an embodiment, the exhaust port of the adiabatic compressor is further communicated with the turbine and serves as a cooling flow for the turbine.

[0015] As an embodiment, the exhaust port of the gasifier is communicated with the steam generator for gasifying water.

[0016] As an embodiment, the exhaust port of the low-temperature pipeline of the high-temperature syngas regenerator is communicated with the gasifier through a throttle valve; a water separator and a sulfur separator are sequentially connected in series between the first cooler and the hydrogen separator.

[0017] As an embodiment, it further includes a methanol synthesis device, and both the hydrogen capture device and the carbon dioxide capture device are communicated with the methanol synthesis device to supply hydrogen and carbon dioxide to the methanol synthesis device.

[0018] The present invention has the following technical effects compared with the prior art:

[0019] 1. In the present invention, water vapor and carbon dioxide are introduced into the gasifier to participate in gasification, taking into account the flexibility of water gasification and the high efficiency of carbon dioxide gasification. While ensuring the cycle efficiency, the change of the unit load can be quickly responded by adjusting the flow rate of water vapor.

[0020] 2. The present invention utilizes circulating carbon dioxide at low temperature to quench syngas. The mass flow rate of carbon dioxide is relatively large, which overcomes the heat loss caused by the excessive deviation of the mass flow rates of the hot and cold fluid streams in the traditional syngas quenching scheme on the premise of reducing the outlet temperature of the syngas.

[0021] 3. The present invention makes full use of carbon dioxide, without external carbon dioxide emissions. Carbon capture does not require additional energy consumption, realizing the construction of a new low-carbon and high-efficiency coal-fired power generation system.

[0022] Other technical solutions of the present invention have the following technical effects compared with the prior art:

[0023] In the present invention, the power source of the water electrolysis device is renewable power. By combining the electrolysis of water with renewable power to produce hydrogen and pure oxygen combustion power generation, and applying the by-product oxygen to the coal gasification and pure oxygen combustion processes of the coal gasification pure oxygen combustion power generation system, the present invention realizes the full utilization of the electrolysis water products and improves the comprehensive consumption and utilization efficiency of renewable power. Thus, the present invention combines the electrolysis of water to produce hydrogen and pure oxygen power generation, makes full use of the by-product oxygen in the hydrogen production process with renewable energy consumption, and further synthesizes the captured carbon dioxide and hydrogen into methanol, realizing the co-production of "electricity-hydrogen-alcohol", and constructing a poly-generation system that can realize the consumption of renewable energy and efficient power generation for hydrogen production and carbon capture.

[0024] In the flue gas recuperation process of the present invention, a recompression retrofit measure is introduced. A part of the flue gas that has not been intercooled and compressed is adiabatically pressurized and directly mixed with the main circulation flow, reducing the heat loss caused by the mismatch of heat capacity due to the excessive pressure difference between the hot and cold fluid streams in the flue gas recuperation process, and effectively improving the energy utilization efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic structural diagram of a coal gasification pure oxygen combustion power generation system in an embodiment of the present invention.

[0027] Description of the reference numerals:

[0028] 1. Gasifier; 2. Steam generator; 3. High-temperature syngas recuperator; 4. Low-temperature syngas recuperator; 5. First cooler; 6. Water separator; 7. Sulfur separator; 8. Hydrogen separator; 9. First multi-stage intercooled compressor; 10. Hydrogen capture device; 11. Second multi-stage intercooled compressor; 12. Combustion chamber; 13. Turbine; 14. Generator; 15. High-temperature flue gas recuperator; 16. Low-temperature flue gas recuperator; 17. Second cooler; 18. Third multi-stage intercooled compressor; 19. Carbon dioxide capture device; 20. Pump; 21. Adiabatic compressor; 22. Fourth multi-stage intercooled compressor; 23. Throttle valve; 24. Water electrolysis device; 25. Fifth multi-stage intercooled compressor; 26. Sixth multi-stage intercooled compressor; 27. Seventh multi-stage intercooled compressor; 28. Methanol synthesis device. Detailed implementation manners

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The object of the present invention is to provide a coal gasification pure oxygen combustion power generation system to solve the problems existing in the prior art, introduce water vapor and carbon dioxide into the gasifier to participate in gasification, taking into account the flexibility of water gasification and the high efficiency of carbon dioxide gasification, and making full use of the heat in the system.

[0031] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0032] As Figure 1As shown in the figure, this embodiment provides a coal gasification pure oxygen combustion power generation system, which includes a gasifier 1, a steam generator 2, a hydrogen separator 8, a combustion chamber 12, and a turbine 13. Among them, the gasifier 1 is used for coal gasification to generate syngas and has a slag discharge port; the steam generator 2 is used to supply gasification water steam to the gasifier 1; the hydrogen separator 8 is used to separate hydrogen in the syngas; the combustion chamber 12 is used to burn the syngas; the intake port of the turbine 13 is connected to the exhaust port of the combustion chamber 12 and is used to drive the generator 14 to generate electricity by using the high-temperature flue gas of the combustion chamber 12; the syngas outlet of the gasifier 1 is sequentially connected to the syngas intake port of the hydrogen separator 8 through the high-temperature pipeline of the high-temperature syngas recuperator 3, the high-temperature pipeline of the low-temperature syngas recuperator 4, and the first cooler 5. The first hydrogen exhaust port of the hydrogen separator 8 is used to connect to the hydrogen capture device 10. The syngas exhaust port of the hydrogen separator 8 is sequentially connected to the combustion chamber 12 through the second multi-stage intercooling compressor 11 and the low-temperature pipeline of the low-temperature syngas recuperator 4; the exhaust port of the turbine 13 is sequentially connected to the second cooler 17 through the high-temperature pipeline of the high-temperature flue gas recuperator 15 and the high-temperature pipeline of the low-temperature flue gas recuperator 16. The exhaust port of the second cooler 17 is connected to the third multi-stage intercooling compressor 18 and the fourth multi-stage intercooling compressor 22 arranged in parallel. The exhaust port of the third multi-stage intercooling compressor 18 is connected to the carbon dioxide capture device 19 and the low-temperature pipeline of the low-temperature flue gas recuperator 16 arranged in parallel. The exhaust port of the low-temperature pipeline of the low-temperature flue gas recuperator 16 is connected to the intake port of the low-temperature pipeline of the high-temperature syngas recuperator 3 through the low-temperature pipeline of the high-temperature flue gas recuperator 15. The exhaust port of the low-temperature pipeline of the high-temperature syngas recuperator 3 is connected to the gasifier 1 and the combustion chamber 12. The exhaust port of the fourth multi-stage intercooling compressor 22 is connected to the exhaust port of the gasifier 1.

[0033] During operation, the steam generator 2 supplies steam to the gasifier 1, which can respond quickly during load adjustment to ensure the supply of gasifying agent. Coal generates high-temperature raw syngas through the gasifier 1. After the high-temperature raw syngas recovers heat through the high-temperature synthesizer recuperator and the low-temperature syngas recuperator 4, it is cooled by the first cooler 5 and then enters the hydrogen separator 8 to separate hydrogen in the syngas. The purified syngas after dehydrogenation is compressed by the second multi-stage intercooled compressor 11 and then enters the low-temperature syngas recuperator 4 to be preheated by the raw syngas, and finally is introduced into the combustion chamber 12 for combustion. The high-temperature flue gas generated after the combustion in the combustion chamber 12 does work on the turbine 13, and the turbine 13 drives the connected generator 14 to generate electricity. The exhausted steam after doing work sequentially recovers heat through the high-temperature flue gas recuperator 15 and the low-temperature flue gas recuperator 16 and heats the circulating carbon dioxide. The flue gas after heat recovery is further cooled by the second cooler 17 and then divided into two streams. One stream of flue gas is compressed by the fourth multi-stage intercooled compressor 22 and then mixed and quenched with the high-temperature raw syngas at the outlet of the gasifier 1 to reduce the temperature of the raw syngas and ensure the safety of the subsequent heat exchange process. The remaining flue gas is pressurized by the third multi-stage intercooled compressor 18. Part of it is separated and introduced into the carbon capture device 19 for carbon capture, and the other part, as the main circulating carbon dioxide, is pressurized by the pump 20 and then sequentially passes through the low-temperature flue gas recuperator 16, the high-temperature flue gas recuperator 15, and the high-temperature syngas recuperator 3 to be preheated by the low-temperature flue gas, the high-temperature flue gas, and the high-temperature raw syngas. The carbon dioxide at the outlet of the high-temperature syngas recuperator 3 is divided into two streams. One stream enters the gasifier 1 to participate in gasification, and the other stream is introduced into the combustion chamber 12 to absorb the combustion heat of the syngas.

[0034] Thus, in this embodiment, steam and carbon dioxide are introduced into the gasifier 1 to participate in gasification, taking into account the flexibility of water gasification and the high efficiency of carbon dioxide gasification. While ensuring the cycle efficiency, the change of the unit load can be quickly responded to by adjusting the flow rate of steam. Moreover, in this embodiment, the circulating carbon dioxide at low temperature is used to quench the syngas. The mass flow rate of carbon dioxide is relatively large, and heat loss caused by the too large mass flow rate deviation between the cold and hot fluid streams in the traditional syngas quenching scheme is overcome on the premise of reducing the outlet temperature of the syngas. In addition, carbon dioxide is fully utilized in this embodiment, and there is no carbon dioxide emission externally. Carbon capture does not require additional energy consumption, realizing the construction of a new low-carbon and high-efficiency coal-fired power generation system.

[0035] In this embodiment, the disassembly and layout of the flue gas recuperator can flexibly adjust the heat load of the flue gas heat exchanger, reduce the heat deviation, and ensure the safe operation during load change.

[0036] In this embodiment, the exhaust port of the gasifier 1 is connected to the steam generator 2 for gasifying water. The syngas discharged from the steam generator 2 then enters the high-temperature syngas recuperator 3 and the low-temperature syngas recuperator 4 in sequence to conduct heat exchange on the syngas, and the heat of the syngas can be fully recovered and utilized.

[0037] As an embodiment, this example further includes an electrolytic water device 24. The second hydrogen exhaust port of the electrolytic water device 24 is used to communicate with the hydrogen capture device 10; the oxygen exhaust port of the electrolytic water device 24 is communicated with the gasifier 1 and the combustion chamber 12. This example further includes a hydrogen capture device 10. The hydrogen discharged from the second hydrogen exhaust port converges with the hydrogen discharged from the first hydrogen exhaust port after passing through the seventh multi-stage intercooled compressor 27, and is then captured by the hydrogen capture device 10 after being compressed by the first multi-stage intercooled compressor 9. The hydrogen is separated from the low-temperature syngas and captured together with the by-product hydrogen produced by electrolytic water for oxygen production, realizing the co-production of electricity and hydrogen, and avoiding the safety operation and efficiency problems caused by too high hydrogen content in the syngas. Moreover, the syngas produced by water gasification is the main fuel for the system's power production, and the hydrogen in the syngas is one of the main sources for the co-production of hydrogen in the system. The production ratio of hydrogen and electricity can be adjusted by adjusting the ratio of water and carbon dioxide, realizing the flexible operation of electricity-hydrogen co-production.

[0038] In this example, the power source of the electrolytic water device 24 is renewable power. By combining the electrolysis of water to produce hydrogen from renewable power with pure oxygen combustion power generation in this example, the by-product oxygen is applied to the gasification and pure oxygen combustion processes of the pure oxygen combustion power generation system for coal gasification, realizing the full utilization of the electrolytic water products and improving the comprehensive consumption and utilization efficiency of renewable power.

[0039] As an embodiment, this example further includes a methanol synthesis device 28. The methanol synthesis device 28 is respectively communicated with the hydrogen capture device 10 and the carbon dioxide capture device 19, and is used to produce methanol by using the captured hydrogen and carbon dioxide. Thus, this example combines the electrolysis of water to produce hydrogen with pure oxygen power generation, fully utilizes the by-product oxygen in the process of hydrogen production by consuming renewable energy, and further synthesizes the captured carbon dioxide and hydrogen into methanol, realizing the co-production of "electricity-hydrogen-alcohol", and constructing a poly-generation system for realizing the consumption of renewable energy and efficient power generation for hydrogen production and carbon capture.

[0040] As an embodiment, this example further includes a fifth multi-stage intercooled compressor 25. The intake port of the fifth multi-stage intercooled compressor 25 is communicated with the oxygen exhaust port, and the exhaust port of the fifth multi-stage intercooled compressor 25 is communicated with the gasifier 1 and the combustion chamber 12.

[0041] As an embodiment, this example further includes a sixth multi-stage intercooled compressor 26. The intake port of the sixth multi-stage intercooled compressor 26 is communicated with the exhaust port of the fifth multi-stage intercooled compressor 25, and the exhaust port of the sixth multi-stage intercooled compressor 26 is communicated with the combustion chamber 12.

[0042] As an embodiment, this example further includes an adiabatic compressor 21. The inlet of the adiabatic compressor 21 is communicated with the exhaust port of the second cooler 17. That is, in this example, the low-temperature flue gas discharged from the second cooler 17 is divided into three streams. The above content has explained two of them. This stream of flue gas is further divided into two parts after being compressed (heated and pressurized) by the adiabatic compressor 21. One part enters the turbine 13 as the cooling flow of the turbine 13 to ensure the safe operation of the turbine 13, and the other part serves as the recompression flow and is mixed with the flue gas flow at the exhaust port of the low-temperature pipeline in the low-temperature flue gas recuperator 16. On the one hand, it is pressure-matched with the low-temperature flue gas compressed by the third multi-stage intercooled compressor 18, alleviates the heat capacity mismatch caused by the excessive pressure difference between the cold and hot fluid streams, reduces the average heat transfer temperature difference in the flue gas heat recovery process, reduces the heat loss in the heat recovery process, and improves the utilization rate of flue gas waste heat. By setting the adiabatic compressor 21 in this example, the heat transfer temperature difference in the flue gas heat recovery process can be reduced, and the utilization efficiency of flue gas waste heat can be improved.

[0043] In order to be able to adjust the amount of carbon dioxide introduced into the gasifier 1, in this example, the exhaust port of the low-temperature pipeline of the high-temperature syngas recuperator 3 is communicated with the gasifier 1 through a throttle valve 23.

[0044] In this example, a water separator 6 and a sulfur separator 7 are sequentially connected in series between the first cooler 5 and the hydrogen separator 8 to improve the cleanliness of the syngas entering the hydrogen separator 8.

[0045] Adaptations made according to actual needs are all within the protection scope of the present invention.

[0046] Specific examples are used in the present invention to elaborate on the principles and implementation manners of the present invention. The descriptions of the above examples are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A coal gasification pure oxygen combustion power generation system, characterized in that: include: A gasifier, wherein the gasifier is used to gasify coal to generate synthesis gas; A steam generator, the steam generator is used to provide gasification water vapor to the gasifier; A hydrogen separator for separating hydrogen from synthesis gas; a combustion chamber for burning the synthesis gas; and a turbine, the air inlet of the turbine being in communication with the exhaust port of the combustion chamber, for utilizing the high temperature flue gas of the combustion chamber to drive the generator to generate electricity; The synthesis gas outlet of the gasifier is connected to the synthesis gas inlet of the hydrogen separator through the high-temperature pipeline of the high-temperature synthesis gas regenerator, the high-temperature pipeline of the low-temperature synthesis gas regenerator, and the first cooler in sequence. The first hydrogen exhaust port of the hydrogen separator is used to connect the hydrogen capture device. The synthesis gas exhaust port of the hydrogen separator is connected to the combustion chamber through the second multi-stage intercooling compressor and the low-temperature pipeline of the low-temperature synthesis gas regenerator in sequence. The exhaust port of the turbine is connected to the second cooler through the high-temperature pipeline of the high-temperature flue gas reheater and the high-temperature pipeline of the low-temperature flue gas reheater in sequence. The exhaust port of the second cooler is connected to the third multi-stage interstage cold compressor and the fourth multi-stage interstage cold compressor arranged in parallel. The exhaust port of the third multi-stage interstage cold compressor is connected to the parallel carbon dioxide capture device and the low-temperature pipeline of the low-temperature flue gas reheater. The low-temperature pipeline exhaust port of the low-temperature flue gas reheater is connected to the low-temperature pipeline air inlet of the high-temperature synthesis gas reheater through the low-temperature pipeline of the high-temperature flue gas reheater. The low-temperature pipeline exhaust port of the high-temperature synthesis gas reheater is connected to the gasifier and the combustion chamber. The exhaust port of the fourth multi-stage interstage cold compressor is connected to the exhaust port of the gasifier.

2. The coal gasification pure oxygen combustion power generation system according to claim 1, characterized in that: It also includes a water electrolysis device, wherein the second hydrogen exhaust port of the water electrolysis device is used to communicate with the hydrogen capture device; and the oxygen exhaust port of the water electrolysis device is communicated with the gasifier and the combustion chamber.

3. The coal gasification pure oxygen combustion power generation system according to claim 2, characterized in that: It also includes a hydrogen capture device, and the second hydrogen exhaust port is connected to the first hydrogen exhaust port through a seventh inter-stage cold compressor, and is connected to the hydrogen capture device through a first multi-stage inter-stage cold compressor.

4. The coal gasification pure oxygen combustion power generation system according to claim 2, characterized in that: It also includes a fifth multi-stage inter-stage cold compressor, the air inlet of the fifth multi-stage inter-stage cold compressor is connected to the oxygen exhaust port, and the exhaust port of the fifth multi-stage inter-stage cold compressor is connected to the gasifier and the combustion chamber.

5. The coal gasification pure oxygen combustion power generation system according to claim 4, characterized in that: It also includes a sixth multi-stage inter-stage cold compressor, the air inlet of the sixth multi-stage inter-stage cold compressor is connected to the exhaust port of the fifth multi-stage inter-stage cold compressor, and the exhaust port of the sixth multi-stage inter-stage cold compressor is connected to the combustion chamber.

6. The coal gasification pure oxygen combustion power generation system according to claim 1, characterized in that: It also includes an adiabatic compressor, the air inlet of the adiabatic compressor is connected to the exhaust port of the second cooler, and the exhaust port of the adiabatic compressor is connected to the low-temperature pipeline exhaust port of the low-temperature flue gas regenerator and the low-temperature pipeline air inlet of the high-temperature flue gas regenerator through a three-way joint.

7. The coal gasification pure oxygen combustion power generation system according to claim 6, characterized in that: The exhaust port of the adiabatic compressor is also connected to the turbine to serve as a cooling flow for the turbine.

8. The coal gasification pure oxygen combustion power generation system according to claim 1, characterized in that: The exhaust port of the gasifier is connected to the steam generator for gasifying water; the low-temperature pipeline exhaust port of the high-temperature synthesis gas regenerator is connected to the gasifier through a throttle valve.

9. The coal gasification pure oxygen combustion power generation system according to claim 1, characterized in that: A water separator and a sulfur separator are sequentially arranged in series between the first cooler and the hydrogen separator.

10. The coal gasification pure oxygen combustion power generation system according to claim 3, characterized in that: It also includes a methanol synthesis device. The hydrogen capture device and the carbon dioxide capture device are both connected to the methanol synthesis device and are used to supply hydrogen and carbon dioxide to the methanol synthesis device.

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