CN109372636B - Three-cycle integrated coal gasification fuel cell power generation system and method with zero carbon emission - Google Patents

Abstract

The invention provides a three-cycle integrated coal gasification fuel cell power generation system and a method with zero carbon emission, wherein the three-cycle integrated coal gasification fuel cell power generation system comprises a coal preparation unit, a gasification furnace, a waste heat boiler, a circulating gas compressor, a first gas heater, a water scrubber, a second gas heater, a carbonyl sulfide hydrolysis reactor, a desulfurization unit, a humidifier, an ejector, a fuel cell, a pure oxygen combustor, a gas turbine, an air compressor, a cathode regenerator, an air turbine, a waste heat boiler, a steam turbine, a first carbon dioxide compressor, a second carbon dioxide compressor, a cryogenic air separation unit and an oxygen compressor, wherein the first fuel cell power generation system generates power, the second fuel cell power generation system generates power by the gas turbine, the third fuel cell power generation system generates power by the steam engine, and the step utilization of energy is realized to the greatest extent in two aspects of chemical energy and physical energy.

Description

A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system and method

Technical field

The invention belongs to the technical field of clean coal power generation, and specifically relates to a zero-carbon emission three-cycle integral coal gasification fuel cell power generation system and method.

Background technique

Coal is my country's most important basic energy source, and its status will not change for a long time to come. my country's coal-fired power generation technology has made great progress after more than ten years of hard work. The coal consumption of one million kilowatt twice-reheated ultra-supercritical coal-fired generating units can reach 265 g/kWh, which is an international leader. The emission indicators continue to improve, and ultra-low emission pollutant control technology can control the main pollutants of coal-fired units to the emission levels of natural gas combined cycle power generation. In 2012, my country completed and put into operation the first 250,000-kilowatt integrated coal gasification combined cycle IGCC demonstration power station. Its net efficiency is designed to be 41%. The actual environmental performance of the power station can reach or even exceed the emission level of natural gas combined cycle power generation. Nearly zero emissions of conventional pollutants can be achieved.

The U.S. Environmental Protection Agency recently announced that the carbon dioxide emission standard for power generation technology is 636 grams CO ₂ /kWh. After calculation, it is difficult for ultra-supercritical coal-fired power generation units and IGCC to achieve this carbon emission target under the current technical level. This means that coal-based power generation technology still needs to further improve net efficiency or capture carbon dioxide. 700℃ advanced ultra-supercritical coal-fired units and high-parameter IGCC can significantly improve the net efficiency of coal-based power generation technology, but there is still a bottleneck problem before the 700℃ advanced ultra-supercritical coal-fired units can achieve commercial demonstration. Carbon dioxide capture using existing technologies or technologies that are feasible in the near future will not only significantly increase equipment investment, but also significantly reduce power generation efficiency.

The integrated coal gasification fuel cell power generation system IGFC is a power generation system that combines IGCC with high-temperature fuel cells. Its energy conversion efficiency is not limited by the Carnot cycle efficiency. It can greatly improve the efficiency of coal power and easily achieve near-zero emissions of pollutants and carbon dioxide. It is an important development direction of clean coal power generation technology.

Contents of the invention

The purpose of the present invention is to provide a zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system and method, which solves the shortcomings of existing ultra-supercritical coal-fired generating units and IGCCs that are difficult to achieve carbon emission indicators. The present invention It can further improve the net power generation efficiency of coal-based power generation systems.

In order to achieve the above objects, the technical solution adopted by the present invention is:

The invention provides a zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system, which includes a coal preparation unit, a gasifier, a waste heat boiler, a circulating gas compressor, a first gas heater, a water washing tower, a second gas Gas heater, carbonyl sulfide hydrolysis reactor, desulfurization unit, humidifier, ejector, fuel cell, pure oxygen burner, gas turbine, air compressor, cathode regenerator, air turbine, waste heat boiler, steam turbine , a first carbon dioxide compressor, a second carbon dioxide compressor, a cryogenic air separation unit and an oxygen compressor, wherein the outlet of the coal preparation unit is connected to the pulverized coal inlet of the gasifier, and the high-temperature rough syngas outlet at the top of the gasifier Connect the inlet of the waste heat boiler, the saturated steam outlet of the waste heat boiler is connected to the inlet of the waste heat boiler, the crude synthesis gas outlet of the waste heat boiler is connected to the inlet of the circulating gas compressor and the hot side inlet of the first gas heater, and the low-temperature synthesis of the circulating gas compressor The gas outlet is connected to the inlet of the waste heat boiler;

The hot side outlet of the first gas heater is connected to the hot side inlet of the second gas heater through the water washing tower, and the hot side outlet of the second gas heater is connected to the cold side of the second gas heater through the carbonyl sulfide hydrolysis reactor. Side inlet, the cold side outlet of the second gas heater is connected to the inlet of the desulfurization unit, the outlet of the desulfurization unit is connected to the cold side inlet of the first gas heater through the humidifier, and the cold side outlet of the first gas heater passes through The ejector is connected to the anode inlet of the fuel cell, and the anode tail gas outlet of the fuel cell is connected to the inlet of the ejector and the inlet of the pure oxygen burner;

The pure oxygen inlet of the pure oxygen burner is connected to the oxygen outlet of the oxygen compressor, the outlet of the pure oxygen burner is connected to the gas turbine, and the tail gas outlet of the gas turbine is connected to the waste heat boiler;

The outlet of the air compressor is connected to the cold side inlet of the cathode regenerator, the cold side outlet of the cathode regenerator is connected to the cathode inlet of the fuel cell, the cathode outlet of the fuel cell is connected to the hot side inlet of the cathode regenerator, and the cathode regenerator's The hot side outlet is connected to the inlet of the air turbine, and the tail gas outlet of the air turbine is connected to the waste heat boiler;

The outlet of the air compressor is also connected to the inlet of the cryogenic air separation unit, the oxygen outlet of the cryogenic air separation unit is connected to the inlet of the oxygen compressor; the pure oxygen outlet of the oxygen compressor is connected to the oxygen inlet of the gasifier;

The high-pressure superheated steam outlet of the waste heat boiler is connected to the steam turbine, and part of the medium-pressure steam outlet of the steam turbine is connected to the inlet of the gasification furnace.

Preferably, a second carbon dioxide compressor is disposed between the combustion exhaust gas outlet of the waste heat boiler and the ejector, and the inlet of the ejector is also connected to part of the medium-pressure steam outlet of the steam turbine.

Preferably, a first carbon dioxide compressor is disposed between the combustion exhaust gas outlet of the waste heat boiler and the gasification furnace.

Preferably, the combustion tail gas outlet of the waste heat boiler is also connected to the inlet of the first waste heat recovery heat exchanger, the outlet of the first waste heat recovery heat exchanger is connected to the inlet of the multi-stage compressor; the outlet of the multi-stage compressor is connected to the liquid carbon dioxide Reservoir tank.

Preferably, the crude syngas outlet of the waste heat boiler is connected to a dust removal unit, and the dust removal unit is connected to the inlet of the circulating gas compressor and the hot side inlet of the first gas-gas heater.

Preferably, the desulfurization unit is provided with a wastewater outlet and an exhaust gas outlet, wherein the wastewater outlet and the exhaust gas outlet are respectively connected to a water treatment unit and a sulfur recovery unit.

Preferably, the cold side outlet of the second gas heater is connected to a low-temperature waste heat recovery unit and a syngas cooler in sequence, wherein the outlet of the syngas cooler is connected to the inlet of the desulfurization unit.

Preferably, a second waste heat recovery heat exchanger is disposed between the outlet of the air compressor and the inlet of the cryogenic air separation unit.

A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation method, based on a zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system, includes the following steps:

Raw coal is ground and dried in the coal preparation unit to form dry coal powder, which is then transported to the gasifier. Part of the pure oxygen from the outlet of the oxygen compressor and a small amount of medium-pressure steam extracted from the middle of the turbine are simultaneously sent to the gasifier for reaction, and gasification The high-temperature crude syngas produced at the top of the furnace is mixed with the low-temperature syngas at the outlet of the circulating gas compressor and quenched before being sent to the waste heat boiler; the saturated steam generated by the waste heat boiler is sent to the waste heat boiler for further heating;

Part of the crude syngas after recovering waste heat from the waste heat boiler is sent to the inlet of the circulating gas compressor, and the other part of the syngas enters the hot side inlet of the first gas heater for cooling. The cooled syngas is sent to the water washing tower, and the synthesis gas is synthesized at the outlet of the water washing tower. The gas is sent to the hot side inlet of the second gas heater, and after further cooling, it is sent to the carbonyl sulfide hydrolysis reactor, and then enters the cold side inlet of the second gas heater. After the synthesis gas is reheated, it enters the desulfurization unit, and the desulfurization unit generates The clean syngas is sent to the humidifier for humidification and then enters the cold side of the first gas heater;

The cold side outlet of the first gas heater is connected to the inlet of the ejector, the ejector ejector part of the exhaust gas from the anode outlet of the fuel cell, and the syngas from the ejector outlet enters the fuel cell anode for reaction;

The remaining exhaust gas from the anode outlet of the fuel cell enters the pure oxygen burner and undergoes a catalytic combustion reaction with part of the pure oxygen from the oxygen compressor outlet to produce combustion exhaust gas. After the combustion exhaust gas undergoes work in the gas turbine, it is sent to the waste heat boiler;

After a stream of air is pressurized by the cathode air compressor, part of it is sent to the cold side inlet of the cathode regenerator. The high-temperature air from the cold side outlet is sent to the cathode inlet of the fuel cell. After reacting in the fuel cell, it is sent to the cathode regenerator to heat The side inlet is used to cool down and send the air to the turbine. After the air turbine is driven to rotate and perform work, it is sent to the waste heat boiler;

The other part of the air from the outlet of the cathode air compressor is sent to the cryogenic air separation unit. An argon gas separation process is set up in the cryogenic air separation unit. The high-purity oxygen produced by the cryogenic air separation unit is sent to the inlet of the oxygen compressor;

The waste heat boiler recovers the recuperation of the exhaust gas from the gas turbine and the air turbine, and at the same time superheats the saturated steam generated by the waste heat boiler. The waste heat boiler generates high-pressure superheated steam and sends it to the steam turbine to perform work.

Preferably, the zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system includes a first carbon dioxide compressor, a second carbon dioxide compressor, a carbon dioxide multi-stage compressor and a first waste heat recovery heat exchanger, wherein,

The combustion exhaust gas from the waste heat boiler is divided into three streams after being cooled. The first stream is sent to the gasifier through the first carbon dioxide compressor; the second stream is sent to the ejector through the second carbon dioxide compressor; the third stream is sent to the first The waste heat recovery heat exchanger performs condensation, cooling and moisture removal, and then is sent to the carbon dioxide multi-stage compressor to form high-purity liquid carbon dioxide.

Compared with the prior art, the beneficial effects of the present invention are:

The invention provides a zero-carbon emission three-cycle integral coal gasification fuel cell power generation system, which is provided with a three-cycle power generation system, one of which is fuel cell power generation, the second is gas turbine power generation, and the third is steam engine power generation. It maximizes the cascade utilization of energy in terms of energy and physical energy; at the same time, the system eliminates the CO water vapor shift reaction unit, simplifies the power generation system process, and avoids the heating value of the synthesis gas caused by the CO water vapor shift reaction process. It is greatly reduced and the net power generation efficiency of the system is improved; because the system uses CO ₂ gas and pure oxygen to transport pulverized coal, and apart from water, CO ₂ gas and pure oxygen contain very few other components, so the combustion exhaust gas of the fuel cell Except for water vapor, most of the remaining gas is _CO2 gas. After expansion and cooling, high-purity _CO2 products can be produced without using a purification device.

A three-cycle integral coal gasification fuel cell power generation method with zero carbon emissions. A three-cycle power generation method is set up. One is fuel cell power generation, the other is gas turbine power generation, and the third is steam engine power generation. It combines chemical energy and physical energy. In two aspects, the cascade utilization of energy is maximized; at the same time, the system eliminates the CO water vapor shift reaction unit, simplifies the power generation system process, and avoids the significant reduction in the calorific value of the syngas caused by the CO water vapor shift reaction process, improving the The net power generation efficiency of the system is improved; because the system uses CO ₂ gas and pure oxygen to transport pulverized coal, and apart from water, CO ₂ gas and pure oxygen contain very few other components, so the combustion exhaust of the fuel cell contains only water vapor. Most of the rest is _CO2 gas. After expansion and cooling, high-purity _CO2 products can be produced without using a purification device.

Furthermore, the pure oxygen produced by the air separation unit is also of high purity due to the argon separation process.

Description of drawings

Figure 1 is a schematic structural diagram of the three-cycle integrated coal gasification fuel cell power generation system of the present invention;

Among them, 1. Coal preparation unit 2, gasifier 3, waste heat boiler 4, dust removal unit 5, circulating gas compressor 6, first gas heater 7, water washing tower 8, second gas heater 9, carbonyl sulfide Hydrolysis reactor 10, waste heat recovery unit 11, syngas cooler 12, desulfurization unit 13, humidifier 14, water treatment unit 15, sulfur recovery unit 16, ejector 17, fuel cell 18, pure oxygen burner 19, Gas turbine 20, air compressor 21, first heat recovery heat exchanger 22, cathode regenerator 23, air turbine 24, waste heat boiler 25, steam turbine 26, first carbon dioxide compressor 27, second carbon dioxide compressor 28 , second waste heat recovery heat exchanger 29, carbon dioxide multi-stage compressor 30, cryogenic air separation unit 31, oxygen compressor

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the invention provides a zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system, including a coal preparation unit 1, a gasification furnace 2, a waste heat boiler 3, a dust removal unit 4, and a circulating gas compressor 5 , first gas heater 6, water washing tower 7, second gas heater 8, carbonyl sulfide hydrolysis reactor 9, waste heat recovery unit 10, syngas cooler 11, desulfurization unit 12, humidifier 13, water treatment Unit 14, sulfur recovery unit 15, ejector 16, fuel cell 17, pure oxygen burner 18, gas turbine 19, air compressor 20, first heat recovery heat exchanger 21, cathode recuperator 22, air ventilation Level 23, waste heat boiler 24, steam turbine 25, first carbon dioxide compressor 26, second carbon dioxide compressor 27, second waste heat recovery heat exchanger 28, third compressor 29, cryogenic air separation unit 30 and oxygen compressor 31. Among them, the outlet of the coal preparation unit 1 is connected to the pulverized coal inlet of the gasifier 2, the high-temperature rough syngas outlet on the top of the gasifier 2 is connected to the inlet of the waste heat boiler 3, and the saturated steam outlet of the waste heat boiler 3 is connected to the waste heat boiler 24. The inlet and the crude syngas outlet of the waste heat boiler 3 are respectively connected to the inlet of the circulating gas compressor 5 and the hot side inlet of the first gas heater 6 through the dust removal unit 4, and the low-temperature syngas outlet of the circulating gas compressor 5 is connected to the waste heat boiler 3 entrance;

The hot side outlet of the first gas heater 6 is connected to the hot side inlet of the second gas heater 8 through the water washing tower 7, and the hot side outlet of the second gas heater 8 is connected to the inlet of the carbonyl sulfide hydrolysis reactor 9. The outlet of the sulfur hydrolysis reactor 9 is connected to the cold side inlet of the second gas heater 8, the cold side outlet of the second gas heater 8 is connected to the inlet of the low temperature waste heat recovery unit 10, and the outlet of the low temperature waste heat recovery unit 10 is connected to the synthesis gas. The inlet of the cooler 11 and the outlet of the syngas cooler 11 are connected to the inlet of the desulfurization unit 12. The outlet of the desulfurization unit 12 is connected to the cold side inlet of the first gas heater 6 through the humidifier 13. The first gas heater 6 The cold side outlet is connected to the anode inlet of the fuel cell 17 through the ejector 16, and the anode outlet of the fuel cell 17 is connected to the inlet of the ejector 16 and the inlet of the pure oxygen burner 18 respectively;

The pure oxygen inlet of the pure oxygen burner 18 is connected to the oxygen outlet of the oxygen compressor 31, the outlet of the pure oxygen burner 18 is connected to the gas turbine 19, and the tail gas outlet of the gas turbine 19 is connected to the waste heat boiler 24;

The outlet of the air compressor 20 is connected to the cold side inlet of the cathode regenerator 22, the cold side outlet of the cathode regenerator 22 is connected to the cathode inlet of the fuel cell 17, and the cathode outlet of the fuel cell 17 is connected to the hot side inlet of the cathode regenerator 22. , the hot side outlet of the cathode regenerator 22 is connected to the inlet of the air turbine 23, and the outlet of the air turbine 23 is connected to the waste heat boiler 24;

The outlet of the air compressor 20 is also connected to the inlet of the second waste heat recovery heat exchanger 21, the outlet of the second waste heat recovery heat exchanger 21 is connected to the inlet of the cryogenic air separation unit 30, and the oxygen outlet of the cryogenic air separation unit 30 Connected to the inlet of the oxygen compressor 31; the pure oxygen outlet of the oxygen compressor 31 is also connected to the inlet of the pure oxygen burner 18;

The high-pressure superheated steam outlet of the waste heat boiler 24 is connected to the steam turbine 25, and part of the medium-pressure steam outlet of the steam turbine 25 is connected to the inlet of the gasification furnace 2;

The combustion tail gas outlet of the waste heat boiler 24 is respectively connected to the inlet of the first carbon dioxide compressor 26, the inlet of the second carbon dioxide compressor 27 and the inlet of the first waste heat recovery heat exchanger 28; the outlet of the first carbon dioxide compressor 26 is connected to the ejector. The inlet of the reactor 16; the outlet of the second carbon dioxide compressor 27 is connected to the inlet of the gasification furnace 2;

The outlet of the first waste heat recovery heat exchanger 28 is connected to the inlet of the multi-stage compressor 29; the outlet of the multi-stage compressor 29 is connected to the liquid carbon dioxide storage tank.

Power generation system process:

The raw coal is ground and dried in the coal preparation unit 1 to form dry coal powder. The high-pressure carbon dioxide gas generated by the second carbon dioxide compressor 27 is transported to the gasifier 2. Part of the pure oxygen at the outlet of the oxygen compressor 31 is mixed with a small amount in the middle of the steam turbine 25 The extracted medium-pressure steam is sent to the gasifier 2 for reaction at the same time. Slag is produced at the bottom of the gasifier 2. The high-temperature crude syngas generated at the top is mixed with the low-temperature syngas from the outlet of the circulating gas compressor 5 and is quenched before being sent to the waste heat boiler. 3; The waste heat boiler 3 generates saturated steam and sends it to the waste heat boiler 24 for further heating. The crude syngas after recovering the waste heat in the waste heat boiler is sent to the dust removal unit 4. A part of the syngas after cooling and dust removal is circulated to the inlet of the circulating gas compressor 5. Another part of the syngas enters the hot side inlet of the first gas heater 6, and is sent to the water washing tower 7 after cooling. The syngas at the outlet of the water washing tower 7 is sent to the hot side inlet of the second gas heater 8, and is further cooled and sent to carbonyl sulfide. The hydrolysis reactor 9 then enters the cold side inlet of the second gas heater 8. After reheating, the syngas enters the low-temperature waste heat recovery unit 10 and then enters the syngas cooler 11 to reduce the syngas to the required temperature for the desulfurization process. After temperature, it enters the desulfurization unit 12. The clean syngas generated by the desulfurization unit is sent to the humidifier 13 for humidification and then enters the cold side of the first gas heater 6. The waste water and waste gas generated by the desulfurization unit 12 enter the water treatment unit 14 and the sulfur gas respectively. The recovery unit 15 forms solid salt and sulfur respectively;

After the syngas at the cold side outlet of the first gas heater 6 is mixed with the medium-pressure steam extracted from the middle of the steam turbine 25 and the high-pressure carbon dioxide gas generated by the first carbon dioxide compressor 26, the carbon monoxide gas in the syngas is diluted and then sent to the injector. The ejector 16 ejector part of the exhaust gas from the anode outlet of the fuel cell 17, and the syngas from the ejector 16 outlet enters the anode of the fuel cell 17 for reaction;

The remaining tail gas from the anode outlet of the fuel cell 17 enters the pure oxygen burner 18 and performs a catalytic combustion reaction with part of the pure oxygen from the outlet of the oxygen compressor 31 to produce combustion tail gas, the main components of which are water vapor and carbon dioxide. After the gas turbine 19 performs work, It is sent to the waste heat boiler 24. The combustion exhaust gas of the waste heat boiler 24 is divided into three streams after being cooled. The first stream is sent to the inlet of the second carbon dioxide compressor 27, the second stream is sent to the inlet of the first carbon dioxide compressor 26, and the third stream is sent to the inlet of the first carbon dioxide compressor 26. The first waste heat recovery heat exchanger 28 condenses, cools, and removes moisture before sending it to the carbon dioxide multi-stage compressor 29 to finally form high-purity liquid carbon dioxide;

After a stream of air is pressurized by the cathode air compressor 20, part of it is sent to the cold side inlet of the cathode regenerator 22. The high-temperature air from the cold side outlet is sent to the cathode inlet of the fuel cell 17, reacts in the fuel cell 17, and is then sent to the cathode. The hot side inlet of the regenerator 22 is cooled and sent to the air turbine 23. After the air turbine 23 is driven to rotate and perform work, it is sent to the waste heat boiler 24, and the waste heat is recovered and discharged into the atmosphere;

Another part of the air from the outlet of the cathode air compressor 20 is sent to the second waste heat recovery heat exchanger 21, and then sent to the cryogenic air separation unit 30. An argon gas separation process is installed in the cryogenic air separation unit 30. The cryogenic air separation unit The polluted nitrogen generated in 30 is discharged into the atmosphere, and the pure argon gas generated can be used as a product to generate high-purity oxygen and send it to the inlet of the oxygen compressor 31;

The waste heat boiler 24 recovers the recuperation of the exhaust gas from the gas turbine 19 and the air turbine 23, and at the same time superheats the saturated steam generated by the waste heat boiler 3. The waste heat boiler 24 generates high-pressure superheated steam and sends it to the steam turbine 25. The electric energy generated by the system is generated by the fuel cell 17 , the gas turbine 19 , the air turbine 23 , and the steam turbine 25 .

Claims (10)

1. A three-cycle integrated coal gasification fuel cell power generation system with zero carbon emissions, which is characterized by including a coal preparation unit (1), a gasifier (2), a waste heat boiler (3), and a circulating gas compressor (5) , first gas heater (6), water washing tower (7), second gas heater (8), carbonyl sulfide hydrolysis reactor (9), desulfurization unit (12), humidifier (13), pilot Injector (16), fuel cell (17), pure oxygen burner (18), gas turbine (19), air compressor (20), cathode regenerator (22), air turbine (23), waste heat Boiler (24), steam turbine (25), first carbon dioxide compressor (26), second carbon dioxide compressor (27), cryogenic air separation unit (30) and oxygen compressor (31), among which the coal preparation unit ( The outlet of 1) is connected to the pulverized coal inlet of the gasifier (2), the high-temperature crude syngas outlet on the top of the gasifier (2) is connected to the inlet of the waste heat boiler (3), and the saturated steam outlet of the waste heat boiler (3) is connected to the waste heat boiler. The inlet of (24), the crude syngas outlet of the waste heat boiler (3) are connected to the inlet of the circulating gas compressor (5) and the hot side inlet of the first gas heater (6), and the low temperature of the circulating gas compressor (5) The syngas outlet is connected to the inlet of the waste heat boiler (3); The hot side outlet of the first gas heater (6) is connected to the hot side inlet of the second gas heater (8) through the water washing tower (7), and the hot side outlet of the second gas heater (8) passes through the carbonyl sulfide The hydrolysis reactor (9) is connected to the cold side inlet of the second gas heater (8), the cold side outlet of the second gas heater (8) is connected to the inlet of the desulfurization unit (12), and the outlet of the desulfurization unit (12) The humidifier (13) is connected to the cold side inlet of the first gas heater (6), and the cold side outlet of the first gas heater (6) is connected to the anode of the fuel cell (17) through the ejector (16). Inlet, the anode tail gas outlet of the fuel cell (17) is connected to the inlet of the ejector (16) and the inlet of the pure oxygen burner (18); The pure oxygen inlet of the pure oxygen burner (18) is connected to the oxygen outlet of the oxygen compressor (31), the outlet of the pure oxygen burner (18) is connected to the gas turbine (19), and the tail gas outlet of the gas turbine (19) is connected to the waste heat. boiler(24); The outlet of the air compressor (20) is connected to the cold side inlet of the cathode regenerator (22), the cold side outlet of the cathode regenerator (22) is connected to the cathode inlet of the fuel cell (17), and the cathode outlet of the fuel cell (17) Connect the hot side inlet of the cathode regenerator (22), the hot side outlet of the cathode regenerator (22) is connected to the inlet of the air turbine (23), and the tail gas outlet of the air turbine (23) is connected to the waste heat boiler (24); The outlet of the air compressor (20) is also connected to the inlet of the cryogenic air separation unit (30), and the oxygen outlet of the cryogenic air separation unit (30) is connected to the inlet of the oxygen compressor (31); the pure oxygen outlet of the oxygen compressor (31) The oxygen outlet is connected to the oxygen inlet of the gasification furnace (2); The high-pressure superheated steam outlet of the waste heat boiler (24) is connected to the steam turbine (25), and part of the medium-pressure steam outlet of the steam turbine (25) is connected to the inlet of the gasification furnace (2). 2. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to claim 1, characterized in that a third gas outlet is provided between the combustion exhaust gas outlet of the waste heat boiler (24) and the ejector (16). A carbon dioxide compressor (26), the inlet of the ejector (16) is also connected with part of the medium-pressure steam outlet of the steam turbine (25). 3. A zero-carbon emission three-cycle integral coal gasification fuel cell power generation system according to claim 1, characterized in that a third gasket is provided between the combustion tail gas outlet of the waste heat boiler (24) and the gasification furnace (2). Two carbon dioxide compressors (27). 4. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to claim 1, characterized in that the combustion tail gas outlet of the waste heat boiler (24) is also connected to a first waste heat recovery heat exchanger ( 28), and the outlet of the first waste heat recovery heat exchanger (28) is connected to the inlet of the multi-stage compressor (29); the outlet of the multi-stage compressor (29) is connected to the liquid carbon dioxide storage tank. 5. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to claim 1, characterized in that the crude syngas outlet of the waste heat boiler (3) is connected to a dust removal unit (4), and the dust removal unit (4) The unit (4) connects the inlet of the circulating gas compressor (5) and the hot side inlet of the first gas heater (6). 6. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to claim 1, characterized in that the desulfurization unit (12) is provided with a waste water outlet and a waste gas outlet, wherein the waste water outlet and the waste gas outlet A water treatment unit (14) and a sulfur recovery unit (15) are respectively connected. 7. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to claim 1, characterized in that the cold side outlet of the second gas heater (8) is connected to a low-temperature waste heat recovery unit ( 10) and a syngas cooler (11), wherein the outlet of the syngas cooler (11) is connected to the inlet of the desulfurization unit (12). 8. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to claim 1, characterized in that, between the outlet of the air compressor (20) and the inlet of the cryogenic air separation unit (30) A second waste heat recovery heat exchanger (21) is provided. 9. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation method, characterized in that it is based on a zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system according to any one of claims 1-8 , including the following steps: Raw coal is ground and dried in the coal preparation unit (1) to form dry coal powder, which is then transported to the gasifier (2). Part of the pure oxygen at the outlet of the oxygen compressor (31) is mixed with a small amount of oxygen extracted from the middle of the steam turbine (25). The high-temperature crude syngas generated at the top of the gasifier (2) is mixed with the low-temperature syngas from the outlet of the circulating gas compressor (5) and quenched, and then sent to the waste heat boiler (3 ); the waste heat boiler (3) generates saturated steam and sends it to the waste heat boiler (24) for further heating; Part of the crude syngas after recovering waste heat in the waste heat boiler is sent to the inlet of the circulating gas compressor (5), and the other part of the syngas enters the hot side inlet of the first gas heater (6) for cooling, and the cooled syngas is sent to the water washing The syngas at the outlet of tower (7) and water washing tower (7) is sent to the hot side inlet of the second gas heater (8). After further cooling, it is sent to the carbonyl sulfide hydrolysis reactor (9), and then enters the second gas heater. (8) Cold side inlet. After reheating, the syngas enters the desulfurization unit (12). The clean syngas generated by the desulfurization unit (12) is sent to the humidifier (13) for humidification and then enters the first gas heater (6 ) cold side; The cold side outlet of the first gas heater (6) is connected to the inlet of the ejector (16), the ejector (16) ejector part of the exhaust gas from the anode outlet of the fuel cell (17), the synthesis of the outlet of the ejector (16) The gas enters the anode of the fuel cell (17) and reacts; The remaining exhaust gas from the anode outlet of the fuel cell (17) enters the pure oxygen burner (18) and undergoes a catalytic combustion reaction with part of the pure oxygen at the outlet of the oxygen compressor (31) to produce combustion exhaust gas. The combustion exhaust gas undergoes work through the gas turbine (19) , sent to the waste heat boiler (24); After a stream of air is pressurized by the cathode air compressor (20), part of it is sent to the cold side inlet of the cathode regenerator (22). The high-temperature air from the cold side outlet is sent to the cathode inlet of the fuel cell (17). ) and then sent to the hot side inlet of the cathode regenerator (22). After cooling, it is sent to the air turbine (23). After the air turbine (23) is driven to rotate and perform work, it is sent to the waste heat boiler (24); Another part of the air from the outlet of the cathode air compressor (20) is sent to the cryogenic air separation unit (30). An argon gas separation process is set up in the cryogenic air separation unit (30). The high-purity air produced by the cryogenic air separation unit (30) Oxygen is fed into the inlet of the oxygen compressor (31); The waste heat boiler (24) recovers the recuperation of the gas turbine (19) and the air turbine (23) to eliminate the exhaust gas, and at the same time superheats the saturated steam generated by the waste heat boiler (3). The waste heat boiler (24) generates high-pressure superheated steam and sends it to The steam turbine (25) does work. 10. A zero-carbon emission three-cycle integrated coal gasification fuel cell power generation method according to claim 9, characterized in that the zero-carbon emission three-cycle integrated coal gasification fuel cell power generation system includes a second carbon dioxide compressor (27 ), the first carbon dioxide compressor (26), the carbon dioxide multi-stage compressor (29) and the first waste heat recovery heat exchanger (28), wherein, The combustion tail gas of the waste heat boiler (24) is divided into three streams after being cooled. The first stream is sent to the gasifier (2) through the second carbon dioxide compressor (27); the second stream is sent to the gasifier (2) through the first carbon dioxide compressor (26). to the ejector (16); the third stream is sent to the first waste heat recovery heat exchanger (28) for condensation, cooling, and moisture removal, and then is sent to the carbon dioxide multi-stage compressor (29) to form high-purity liquid carbon dioxide.