A hydrogen and electricity cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semicoke

Abstract

The application discloses a hydrogen and electricity cogeneration system coupled with coal partial gasification and semi-coke pressurized oxygen-enriched combustion. Compared with the prior art, the semi-coke combustion generally adopts normal pressure air combustion, and the existing gasification atmosphere generally selects air and steam. In the application, a pressurized circulating fluidized bed is used as a reactor for coal partial gasification and semi-coke pressurized oxygen-enriched combustion, pure oxygen and circulating flue gas carbon dioxide are used as the gasification atmosphere. The semi-coke oxygen-enriched combustion can burn the semi-coke as much as possible, enriches CO2 in the combustion products, makes the system capture CO2 easier, more easily realizes 0 carbon emission of the system operation, and improves the overall operation efficiency of the system. The pure oxygen is provided by an air separation oxygen production unit, the carbon dioxide is provided by a carbon dioxide capture unit, and reasonable utilization of waste gas in the system is realized.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy production, specifically to a hydrogen-electricity cogeneration system that couples partial coal gasification with pressurized oxygen-enriched combustion of semi-coke. Background Technology

[0002] Compared with traditional fossil fuels, hydrogen energy, as a green energy source, has broad application prospects. Hydrogen production systems, as a crucial link in hydrogen energy generation, play a vital role in the application and development of hydrogen energy.

[0003] Currently, hydrogen production worldwide still primarily relies on fossil fuels, and China, as a major coal producer, primarily uses coal as its raw material. Traditional coal gasification hydrogen production processes convert coal into hydrogen and other gases (such as carbon monoxide and carbon dioxide) through a series of reactions, without utilizing the chemical energy of these other gases. Therefore, coal-to-hydrogen production suffers from high carbon emissions, high energy consumption, and significant pollutant emissions, limiting its further development and application.

[0004] Current hydrogen production systems mostly employ integrated gasification, which places high demands on equipment operation. Cogeneration systems primarily use air and steam as gasification agents, and the combustion section uses atmospheric pressure air combustion, resulting in a pressure difference between the gasification and combustion sections, leading to energy loss. Furthermore, atmospheric pressure air combustion increases pollutants and is not conducive to carbon dioxide capture. Moreover, current cogeneration systems are mainly used for power cycles, with a low overall hydrogen-to-electricity ratio, primarily used for power generation rather than using hydrogen as a major byproduct. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies and provide a hydrogen cogeneration system that couples coal partial gasification with pressurized oxygen-enriched combustion of semi-coke to achieve efficient coal-to-hydrogen cogeneration while simultaneously achieving zero emissions of pollutants such as sulfur oxides and nitrogen oxides, as well as carbon dioxide greenhouse gases.

[0006] To solve the above-mentioned technical problems, the technical method adopted by the present invention is as follows: The present invention discloses a hydrogen-power cogeneration system that couples coal partial gasification with semi-coke pressurized oxygen-enriched combustion, including an air separation oxygen production unit, a coal partial gasification unit, a semi-coke pressurized oxygen-enriched combustion unit, a gasification product purification and reforming unit, a pressure swing adsorption unit, a steam Rankine cycle power generation unit, and a CO2 capture unit. The air separation oxygen production unit supplies oxygen to the coal partial gasification unit and the semi-coke pressurized oxygen-enriched combustion unit. The coal partial gasification unit performs a coal partial gasification reaction, and sends the crude syngas to the gasification product purification and reforming unit, and sends the solid product semi-coke to the semi-coke combustion unit. The semi-coke pressurized oxygen-enriched combustion unit obtains pure oxygen, semi-coke, and recirculated flue gas from the air separation oxygen production unit, the coal partial gasification unit, and the steam Rankine cycle power generation unit, respectively, carries out combustion reactions, and performs gas-solid separation on the combustion products. The pressurized oxygen-enriched semi-coke combustion unit provides high-temperature steam to the steam Rankine cycle power generation unit, and the steam Rankine cycle power generation unit provides low-temperature steam to the pressurized oxygen-enriched semi-coke combustion unit, thereby realizing steam circulation. The gasification product purification and reforming unit sends the clean syngas that has undergone reforming and change reactions into the pressure swing adsorption unit. The pressure swing adsorption unit separates and stores hydrogen from the clean syngas, and sends the hydrogen-free syngas waste gas to the CO2 capture unit.

[0007] Furthermore, the coal partial gasification unit includes a pressurized circulating fluidized bed gasifier, a coal drying and purification device, and a gas-solid separation device; After being dried and purified by the coal drying and purification device, the pulverized coal is fed into the pressurized circulating fluidized bed gasifier; oxygen is supplied to the pressurized circulating fluidized bed gasifier by the oxygen heater; the carbon dioxide heat exchanger in the CO2 capture unit provides CO2 to the pressurized circulating fluidized bed gasifier, and a partial coal gasification reaction occurs in the pressurized circulating fluidized bed gasifier. The reaction products of the pressurized circulating fluidized bed gasifier are fed into the gas-solid separation device for separation. The gas-solid separation device sends the crude syngas into the waste heat recovery heat exchanger in the gasification product purification and reforming unit, and sends the solid product semi-coke into the pressurized circulating fluidized bed combustion furnace in the semi-coke combustion unit for combustion.

[0008] Furthermore, the semi-coke pressurized oxygen-enriched combustion unit includes a pressurized circulating fluidized bed combustion furnace and a cyclone separator; The feed inlet of the pressurized circulating fluidized bed combustion furnace is connected to the oxygen heater in the air separation oxygen production unit, the gas-solid separation device in the coal partial gasification unit, and the economizer in the steam Rankine cycle power generation unit, so as to obtain pure oxygen, semi-coke, and recirculated flue gas for combustion reaction respectively. The pressurized circulating fluidized bed combustion furnace outputs all water vapor to the low-temperature superheater in the steam Rankine cycle power generation unit and outputs all combustion reaction products to the cyclone separator in the semi-coke pressurized oxygen-enriched combustion unit. The cyclone separator performs gas-solid separation on the combustion products in the pressurized circulating fluidized bed combustion furnace, thereby separating the gaseous flue gas from the solid waste. The cyclone separator sends the solid waste to the medium-temperature superheater in the steam Rankine cycle power generation unit and sends the gaseous flue gas to the high-temperature superheater in the steam Rankine cycle power generation unit.

[0009] Furthermore, the gasification product purification and reforming unit includes a waste heat recovery heat exchanger, a purification device, a reforming reactor, and a syngas heat exchanger. The waste heat recovery heat exchanger recovers the waste heat from the crude gasification products output by the gas-solid separation device and uses the heat as a heat source for the reforming reactor. The outlet of the waste heat recovery heat exchanger is connected to the inlet of the impurity removal device. The impurity removal device desulfurizes the gasification products, removes acidic gases from the crude syngas, and then transports it to the reforming reactor. The high-temperature heat exchanger in the steam Rankine cycle power generation unit supplies steam to the reforming reactor as a reactant in the reforming reaction. The outlet of the reforming reactor is connected to the syngas heat exchanger, which sends the clean syngas that has undergone the reforming and change reactions into the pressure swing adsorption device in the pressure swing adsorption unit.

[0010] Furthermore, the steam Rankine cycle power generation unit includes a low-temperature superheater, a medium-temperature superheater, a high-temperature superheater, a high-pressure steam turbine, a medium-pressure steam turbine, a low-pressure steam turbine, a condenser, a high-temperature heat exchanger, a low-temperature heat exchanger, a water pump, an economizer, a low-temperature reheater, and a high-temperature reheater. The intermediate-temperature superheater receives the high-temperature solid waste output from the cyclone separator and the water vapor discharged from the low-temperature superheater; in the intermediate-temperature superheater, the solid waste heats the water vapor to make the water vapor superheated, and then the intermediate-temperature superheater sends high-temperature water vapor to the high-temperature superheater and outputs solid waste to the low-temperature superheater; the solid waste is sent to the pressurized circulating fluidized bed combustion furnace via the low-temperature superheater. The high-temperature superheater uses the high-temperature gaseous flue gas provided by the cyclone separator to further superheat the high-temperature steam input to the medium-temperature superheater, outputs high-temperature steam to the high-pressure steam turbine, and provides gaseous flue gas to the high-temperature reheater. The high-pressure steam turbine supplies high-temperature steam to the high-temperature heat exchanger and the low-temperature reheater. The low-temperature reheater uses the high-temperature gaseous flue gas supplied by the high-temperature reheater to further heat the high-temperature water vapor passing through the low-temperature reheater, and then supplies the high-temperature water vapor to the high-temperature reheater. The high-temperature reheater provides reheated steam to the medium-pressure steam turbine and outputs gaseous flue gas to the low-temperature reheater. The medium-pressure steam turbine is connected to the low-temperature heat exchanger, and the other is connected to the low-pressure steam turbine. The outlet of the low-pressure steam turbine is connected to the inlet of the condenser. Water vapor is cooled into liquid in the condenser and then pumped into the low-temperature heat exchanger by a water pump to form a water vapor cycle; the water pump can also directly supply water to the low-temperature heat exchanger.

[0011] Furthermore, the steam expands in the high-pressure steam turbine to do work and output electricity, and the steam pressure at the outlet of the high-pressure steam turbine is 4 MPa; Inside the high-temperature reheater, the gaseous flue gas reheats the water vapor, and the water vapor outlet temperature of the high-temperature reheater is 560°C and 4MPa. Steam expands in a medium-pressure steam turbine to generate electricity, and the steam pressure at the outlet of the medium-pressure steam turbine is 2 MPa. Steam expands in a low-pressure steam turbine to generate electricity, and the steam pressure at the outlet is 0.75 MPa.

[0012] Furthermore, the pressure swing adsorption unit includes a pressure swing adsorption device, a hydrogen compressor, a hydrogen storage device, and a waste gas heat exchanger. The pressure swing adsorption device separates hydrogen from the clean synthesis gas and sends it to a hydrogen compressor for pressurization. The pressurized hydrogen is then sent to a hydrogen storage device for storage. The synthesis gas waste gas after hydrogen removal is sent to a waste gas heat exchanger.

[0013] Furthermore, the CO2 capture unit includes a flash reactor, a multi-stage exhaust gas compressor, an exhaust gas purification device, a carbon dioxide heat exchanger, an exhaust gas distillation tower, a carbon dioxide compressor, and a carbon dioxide storage device. The pressure swing adsorption device separates hydrogen from the clean synthesis gas and sends it to a hydrogen compressor for pressurization. The pressurized hydrogen is then sent to a hydrogen storage device for storage. The synthesis gas waste gas after hydrogen removal is sent to a waste gas heat exchanger. The waste gas heat exchanger sends the waste gas into the flash reactor; after the flash reactor discharges the moisture in the waste gas, the dried waste gas is sent to the waste gas multi-stage compressor for pressurization and then passed into the waste gas purification device. After washing, NO is converted into HNO3 in the NOx removal process, and carbon dioxide is separated from the remaining acidic solution. The waste gas purification device sends the washed waste gas into a carbon dioxide heat exchanger, which then transports it to a waste gas distillation tower. The waste gas distillation tower separates the input waste gas into CO and other gases, which are then sent back into the carbon dioxide heat exchanger.

[0014] The carbon dioxide heat exchanger pressurizes a portion of the carbon dioxide and sends it to a carbon dioxide storage device for storage; the other portion of the carbon dioxide is sent to the pressurized circulating fluidized bed gasifier.

[0015] Furthermore, the air separation oxygen production unit includes an air compressor, an air heat exchanger, a low-pressure air distillation tower, a high-pressure air distillation tower, and an oxygen heater; After being cooled by the air compressor, the air is sent to the air heat exchanger and then to the low-pressure distillation tower and the high-pressure air distillation tower respectively. The air is distilled into O2 and N2 in the distillation tower. The high-pressure air distillation tower outputs oxygen and nitrogen to the low-pressure distillation tower; the low-pressure distillation tower supplies oxygen and nitrogen to the air heat exchanger respectively. The air heat exchanger uses air to separate nitrogen and cool and separate oxygen to obtain high-purity oxygen, which is then sent to the oxygen heater. After the oxygen heater heats the oxygen, it is sent to the coal partial gasification unit and the semi-coke pressurized oxygen-enriched combustion unit, respectively.

[0016] Furthermore, the operating temperature of the pressurized circulating fluidized bed gasifier is controlled at 750℃-1150℃, and the operating pressure is controlled at 1-3MPa. Beneficial effects

[0017] 1. Compared to existing technologies that generally use atmospheric pressure air for semi-coke combustion and air and steam for gasification atmospheres, this invention employs a pressurized circulating fluidized bed as the reactor for coal partial gasification and pressurized oxygen-enriched combustion of semi-coke, using pure oxygen and circulating flue gas carbon dioxide as the gasification atmosphere. Oxygen-enriched combustion of semi-coke maximizes combustion of the semi-coke, enriching the CO2 in the combustion products, making CO2 capture easier and achieving zero carbon emissions, thus improving overall system efficiency. The pure oxygen is provided by the air separation oxygen production unit, and the carbon dioxide is provided by the carbon dioxide capture unit, achieving rational utilization of waste gas within the system.

[0018] 2. Compared to existing technologies that directly feed syngas from partial coal gasification into gas turbines for power generation without using a reforming reactor to utilize CO change reactions, resulting in a lower proportion of hydrogen in the products, this invention prioritizes hydrogen production from the syngas products of partial coal gasification to increase hydrogen yield. It includes a gasification product purification and reforming unit that employs steam-methane reforming and CO change reactions to react steam with methane to generate CO, H2, and CO2. Furthermore, the ratio of CO to H2 in the syngas after reforming is adjusted to increase the proportion of H2 and thus improve hydrogen yield.

[0019] 3. Compared to existing technologies that obtain the steam required for the reforming reaction from external sources, this invention connects the outlet of the high-temperature heat exchanger in the steam Rankine cycle power generation unit to the reforming reactor in the gasification product purification and reforming unit, providing it with high-temperature steam as the reaction gas. Furthermore, the heat source for heating the steam participating in the reforming reaction is the waste heat from the syngas in the waste heat recovery heat exchanger. This achieves efficient utilization of steam and heat, improving the system's thermal efficiency. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the hydrogen-electricity cogeneration system of the present invention, which couples partial coal gasification with pressurized oxygen-enriched combustion of semi-coke. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the embodiments. The following embodiments are illustrative and not limiting, and should not be used to limit the scope of protection of the present invention.

[0022] This invention provides a hydrogen-power cogeneration system that utilizes pressurized fluidized bed coal partial gasification and pressurized circulating fluidized bed combustion furnace for semi-pressurized oxygen-enriched combustion, and uses circulating flue gas and pure oxygen as the gasification atmosphere. The cogeneration system includes: an air separation oxygen production unit, a coal partial gasification unit, a semi-coke pressurized oxygen-enriched combustion unit, a gasification product purification and reforming unit, a pressure swing adsorption unit, a steam Rankine cycle power generation unit, and a CO2 capture unit.

[0023] The air separation oxygen production unit includes an air compressor 1, an air heat exchanger 2, an air low-pressure distillation tower 3, an air high-pressure distillation tower 4, and an oxygen heater 5. The coal gasification unit includes a pressurized circulating fluidized bed gasifier 6, a coal drying and purification device 7, and a gas-solid separation device 8; The semi-coke pressurized oxygen-enriched combustion unit includes a pressurized circulating fluidized bed combustion furnace 24 and a cyclone separator 38; The gasification product purification and reforming unit includes a waste heat recovery heat exchanger 9, a purification device 10, a reforming reactor 11, and a syngas heat exchanger 12. The pressure swing adsorption unit includes a pressure swing adsorption device 13, a hydrogen compressor 14, a hydrogen storage device 15, and a waste gas heat exchanger 16. The CO2 capture unit includes a flash reactor 17, a multi-stage exhaust gas compressor 18, an exhaust gas purification device 19, a carbon dioxide heat exchanger 20, an exhaust gas distillation tower 21, a carbon dioxide compressor 22, and a carbon dioxide storage device 23. The steam Rankine cycle power generation unit includes a low-temperature superheater 25, an intermediate-temperature superheater 26, a high-temperature superheater 27, a high-pressure steam turbine 28, an intermediate-pressure steam turbine 29, a low-pressure steam turbine 30, a condenser 31, a high-temperature heat exchanger 32, a low-temperature heat exchanger 33, a water pump 34, an economizer 35, a low-temperature reheater 36, and a high-temperature reheater 37. Air is sent to air heat exchanger 2 by air compressor 1 for cooling, and then sent to low-pressure distillation column 3 and high-pressure distillation column 4 respectively by air heat exchanger 2; the air is distilled into O2 and N2 in the distillation column; High-pressure distillation column 4 outputs oxygen and nitrogen to low-pressure distillation column 3; low-pressure distillation column 3 supplies oxygen and nitrogen to air heat exchanger 2 respectively. Air heat exchanger 2 uses air to separate nitrogen and cool and separate oxygen to obtain oxygen with 99% purity, which is then sent to oxygen heater 5. After the oxygen heater 5 heats the oxygen, it is sent to the coal gasification unit and the semi-coke pressurized oxygen-enriched combustion unit respectively. The oxygen-enriched outlet of the high-pressure distillation column 4 is connected to the inlet of the low-pressure distillation column 3, the oxygen outlet of the low-pressure distillation column 3 is connected to the oxygen inlet of the air heat exchanger 2, and the nitrogen outlet of the low-pressure distillation column 3 is connected to the nitrogen inlet of the air heat exchanger 2. Among them, the air compressor 1 pressurizes to 1MPa, the low-pressure distillation tower 3 and the high-pressure distillation tower 4 have pressures of 0.25MPa and 1MPa respectively, and the oxygen heater 5 heats to 400℃.

[0024] After being dried and purified by the coal drying and purification device 7, the pulverized coal is fed into the pressurized circulating fluidized bed gasifier 6; the oxygen heater 5 supplies oxygen to the pressurized circulating fluidized bed gasifier 6; the carbon dioxide heat exchanger 20 in the CO2 capture unit provides CO2 to the pressurized circulating fluidized bed gasifier 6, and partial coal gasification reaction occurs inside the pressurized circulating fluidized bed gasifier 6; the operating temperature of the pressurized circulating fluidized bed gasifier 6 is controlled at 750℃-1150℃, and the operating pressure is controlled at 1-3 MPa.

[0025] The reaction products of the pressurized circulating fluidized bed gasifier 6 are sent to the gas-solid separation device 8 for separation treatment; the gas-solid separation device 8 sends the crude syngas to the waste heat recovery heat exchanger 9 in the gasification product purification and reforming unit, and sends the solid product semi-coke to the pressurized circulating fluidized bed combustion furnace 24 in the semi-coke combustion unit for combustion. The feed inlet of the pressurized circulating fluidized bed combustion furnace 24 is connected to the oxygen heater 5 in the air separation oxygen production unit, the gas-solid separation device 8 in the coal partial gasification unit, and the economizer 35 in the steam Rankine cycle power generation unit, respectively to obtain pure oxygen, semi-coke, and recirculated flue gas for combustion reaction. The pressurized circulating fluidized bed combustion furnace 24 outputs all water vapor to the low-temperature superheater 25 and all combustion reaction products to the cyclone separator 38; Cyclone separator 38 performs gas-solid separation on the combustion products in pressurized circulating fluidized bed combustion furnace 24, realizing the separation of gaseous flue gas and solid waste; cyclone separator 38 sends solid waste into medium temperature superheater 26 and gaseous flue gas into high temperature superheater 27. The waste heat recovery heat exchanger 9 recovers the waste heat of the crude gasification product output from the gas-solid separation device 8 and uses the heat as the heat source for the reforming reactor 11. The outlet of the waste heat recovery heat exchanger 9 is connected to the inlet of the impurity removal device 10; The impurity removal device 10 uses Selexol technology to desulfurize the gasification products, removes acidic gases from the crude syngas, and then transports it to the reforming reactor 11. High-temperature heat exchanger 32 inputs steam into reforming reactor 11, which is used as a reactant in the reforming reaction. The outlet of the reforming reactor 11 is connected to the syngas heat exchanger 12. The syngas heat exchanger 12 sends the clean syngas that has undergone the reforming reaction and the change reaction into the pressure swing adsorption unit 13. This unit is used to cool the crude syngas product from the coal partial gasification unit, remove acidic gases and liquids from the syngas, and successively use steam methane reforming reaction and CO change reaction to make steam react with methane to generate CO, H2 and CO2, and adjust the ratio of CO and H2 in the syngas after the reforming reaction to increase the H2 yield.

[0026] The reforming reactor operates at a temperature of 780℃ and a pressure of 3.69 MPa. The pressure swing adsorption unit utilizes the difference in adsorption rate of the gasifying agent for different gases under different pressures to separate hydrogen from polluting gases such as carbon dioxide and methane.

[0027] The pressure swing adsorption unit operates at a temperature of 35℃ and a pressure of 2MPa to obtain hydrogen with a purity of 99%. The hydrogen compressor pressurizes the hydrogen to 6MPa for easy storage.

[0028] The pressure swing adsorption unit includes a pressure swing adsorption device 13, a hydrogen compressor 14, a hydrogen storage device 15, and a waste gas heat exchanger 16, and is connected to the gas product purification and reforming unit and the CO2 capture unit.

[0029] After separating hydrogen from the clean synthesis gas by the pressure swing adsorption device 13, the hydrogen is sent to the hydrogen compressor 14 for pressurization. The pressurized hydrogen is then sent to the hydrogen storage device 15 for storage. The synthesis gas waste gas after removing hydrogen is sent to the waste gas heat exchanger 16. The waste gas heat exchanger 16 sends the waste gas into the flash reactor 17; after the flash reactor 17 discharges the moisture in the waste gas, the dried waste gas is sent into the waste gas multi-stage compressor 18 for pressurization and then passed into the waste gas purification device 19. After washing, NO is converted into HNO3 in the NOx removal process, and carbon dioxide is separated from the remaining acidic solution. The waste gas purification device 19 sends the washed waste gas into the carbon dioxide heat exchanger 20, and then through the carbon dioxide heat exchanger 20 it is transported to the waste gas distillation tower 21; the waste gas distillation tower 21 separates the input waste gas into CO2 and other gases, and then sends them into the carbon dioxide heat exchanger 20.

[0030] The carbon dioxide heat exchanger 20 pressurizes a portion of the carbon dioxide via the carbon dioxide compressor 22 and sends it to the carbon dioxide storage device 23 for storage; the other portion of the carbon dioxide is sent to the pressurized circulating fluidized bed gasifier 6. After the high-temperature steam from the medium-pressure steam turbine 29 exchanges heat with the water from the water pump 34 in the low-temperature heat exchanger 33, it is sent to the high-temperature heat exchanger 32 through the low-temperature heat exchanger 33. The high-temperature heat exchanger 32 receives steam from the low-temperature heat exchanger 33 and high-temperature steam from the high-pressure steam turbine 28. After mixing, part of the mixture is sent to the economizer 35 and part is sent to the reformer 11. Economizer 35 exchanges heat between steam from high-temperature heat exchanger 32 and high-temperature flue gas from low-temperature reheater 36, heating the steam to 290°C.

[0031] Economizer 35 transports the heat-exchanged flue gas to waste gas heat exchanger 16 and the heat-exchanged steam to pressurized circulating fluidized bed combustion furnace 24; together with pressurized circulating fluidized bed combustion furnace 24, steam is output to low-temperature superheater 25 to realize steam circulation.

[0032] The intermediate-temperature superheater 26 receives high-temperature solid waste output from the cyclone separator 38 and water vapor discharged from the low-temperature superheater 25. In the intermediate-temperature superheater 26, the solid waste heats the water vapor to make the water vapor superheated. The intermediate-temperature superheater 26 then supplies high-temperature water vapor to the high-temperature superheater 27 and outputs solid waste to the low-temperature superheater 25. The solid waste is then fed into the pressurized circulating fluidized bed combustion furnace 24 via the low-temperature superheater 25. Specifically, the inlet of the low-temperature superheater 25 is connected to the water-cooled wall of the pressurized circulating fluidized bed combustion furnace 24 in the semi-coke combustion unit to obtain water vapor, which is then connected to the intermediate-temperature superheater to obtain solid waste. The outlet of the low-temperature superheater 25 is connected to the inlet of the pressurized circulating fluidized bed combustion furnace 24 to transport the circulating solid waste.

[0033] The high-temperature superheater 27 uses the high-temperature gaseous flue gas provided by the cyclone separator 38 to further superheat the high-temperature steam input to the medium-temperature superheater 26 to 560°C and 24.2 MPa, and outputs high-temperature steam to the high-pressure steam turbine 28. The steam expands in the high-pressure steam turbine to do work and output electricity. The steam at the outlet is at 4 MPa and provides gaseous flue gas to the high-temperature reheater 37. The high-pressure steam turbine 28 supplies high-temperature steam to the high-temperature heat exchanger 32 and the low-temperature reheater 36. The low-temperature reheater 36 uses the high-temperature gaseous flue gas transported by the high-temperature reheater 37 to further heat the high-temperature steam passing through the low-temperature reheater 36, and then transports the high-temperature steam to the high-temperature reheater 37; inside the high-temperature reheater 37, the gaseous flue gas reheats the steam, and the steam outlet temperature is 560℃ and 4MPa.

[0034] The high-temperature reheater 37 provides reheated steam to the medium-pressure steam turbine 29 and outputs gaseous flue gas to the low-temperature reheater 36; the steam expands in the medium-pressure steam turbine 29 to do work and output electricity, and the steam state at the outlet of the medium-pressure steam turbine is 2MPa. One intermediate-pressure steam turbine 29 is connected to the low-temperature heat exchanger 33, and the other is connected to the low-pressure steam turbine 30. The outlet of the low-pressure steam turbine 30 is connected to the inlet of the condenser 31. Steam expands in the intermediate-pressure steam turbine, performing work to generate electricity; the steam pressure at the outlet is 2 MPa. Steam expands in the low-pressure steam turbine 30, performing work to generate electricity; the steam pressure at the outlet is 0.75 MPa.

[0035] Water vapor is cooled into liquid in condenser 31 and sent to low-temperature heat exchanger 33 by water pump 34 to form a water vapor cycle; water pump 34 can also directly supply water to low-temperature heat exchanger 33. Example

[0036] like Figure 1 As shown, pulverized coal enters the pressurized circulating fluidized bed gasifier 6 after passing through the coal drying and purification device 7 and undergoes a partial gasification reaction with the selected gasifying agent (oxygen / circulating flue gas carbon dioxide). The partial gasification products include crude syngas and ungasified semi-coke. The product from the pressurized circulating fluidized bed gasifier 6 passes through the gas-solid separation device 8 to separate the gaseous product from the solid product. The syngas undergoes sensible heat recovery through the waste heat recovery heat exchanger 9, and after cooling, it enters the impurity removal device 10. The crude syngas is desulfurized using Selexol technology to remove acidic gases such as H2S from the crude syngas, preventing corrosion of subsequent equipment and obtaining clean syngas. The syngas then passes through reforming reactor 11, where the reforming reaction and CO change reaction are used to react steam with methane to produce CO, H2 and CO2. The ratio of CO and H2 in the syngas after the reforming reaction is adjusted to increase the H2 yield.

[0037] Syngas is fed into a pressure swing adsorption (PSA) unit 13 to separate gases such as CH4, H2, and CO2, purifying H2. The resulting H2 is then pressurized in a hydrogen compressor 14 and stored in a hydrogen storage device 15 to obtain 99% H2. The waste gas separated by the PSA unit 13 is combined with the flue gas from the economizer 35 and then passes through a flash reactor 17 to remove water vapor. After being pressurized by a multi-stage waste gas compressor 18, it passes through a waste gas purification device 19 to remove acidic solutions. Then, it passes through a waste gas heat exchanger 20 and a waste gas distillation tower 21 to separate carbon dioxide from the remaining nitrogen oxides, obtaining high-purity carbon dioxide. After being pressurized by a carbon dioxide compressor 22, it is sent to a carbon dioxide storage device 23.

[0038] The high-purity oxygen required by the pressurized circulating fluidized bed gasifier 6 and the pressurized circulating fluidized bed combustion furnace 24 comes from the air separation oxygen production unit. Air enters the air compressor 1, then passes through the air heat exchanger 2, and then enters the air low-pressure distillation tower 3 and the air high-pressure distillation tower 4 respectively to separate the oxygen from nitrogen and other waste gases in the air. The oxygen then enters the air heat exchanger 2 to cool and separate it. Finally, the oxygen enters the pressurized circulating fluidized bed gasifier 6 and the pressurized circulating fluidized bed combustion furnace 24 through the oxygen heater 5 to preheat the oxygen.

[0039] Semi-coke from some of the gasification products is separated by a gas-solid separation device and then sent to a pressurized circulating fluidized bed combustion furnace 24 for pressurized oxygen-enriched combustion. The combustion pressure is consistent with that of the gasifier. The generated high-temperature flue gas passes through a cyclone separator 38 to separate the combustion waste from the high-temperature flue gas. The high-temperature solid waste is then heated by a medium-temperature superheater 26 and a low-temperature superheater 25, and then cooled by high-temperature steam before being sent back to the pressurized circulating fluidized bed combustion furnace 24.

[0040] The high-temperature flue gas passes through the high-temperature superheater 27, high-temperature reheater 37, low-temperature reheater 36 and economizer 35 in sequence to heat the high-temperature steam. After being cooled, part of it is sent to the CO2 capture unit to merge with the waste gas separated by pressure swing adsorption for carbon capture. The other part is sent back to the pressurized circulating fluidized bed combustion furnace 24 for carbon dioxide recycling.

[0041] The working medium for coal partial gasification is recycled CO2. In the CO2 capture unit, after drying, compression, cleaning and distillation, the partially purified CO2 is sent back to the pressurized circulating fluidized bed gasifier 6 via the carbon dioxide heat exchanger 20 as a recycled working medium to participate in the partial gasification reaction. Using steam as the working fluid in the steam Rankine cycle power generation unit, water is pressurized to 22.4 MPa by water pump 34 at normal temperature and pressure and enters the circulation system. It passes through low temperature heat exchanger 33 and high temperature heat exchanger 32 respectively and is mixed with exhaust from medium pressure steam turbine 29 and high pressure steam turbine 28. It then passes through economizer 35 and water-cooled wall for heating to become high temperature and high pressure steam. After passing through low temperature superheater 25, medium temperature superheater 26 and high temperature superheater 27, it becomes high pressure superheated steam. The high pressure superheated steam enters high pressure steam turbine 28 to drive the turbine blades to generate electricity. The exhaust passes through low temperature reheater 36 and high temperature reheater 37 to become superheated steam again. Superheated steam passes through the intermediate-pressure steam turbine 29 and the low-pressure steam turbine 30 in sequence to generate electricity. After exhausting, it passes through the condenser 31 to be cooled into liquid water, which is then combined with the feedwater and repressurized by the water pump 34 before entering the steam cycle power generation unit.

[0042] The steam reactants required for the reforming reactor 11 in the gasification product purification and reforming unit are exhaust gases from one of the outlet ports of the high-temperature heat exchanger 32 in the steam Rankine cycle power generation unit.

[0043] This invention employs a pressurized circulating fluidized bed as the reactor for partial coal gasification and pressurized oxygen-enriched combustion of semi-coke. It uses pure oxygen and circulating flue gas carbon dioxide as the gasification atmosphere, featuring a moderate carbon conversion rate in the gasification reaction, high system energy utilization efficiency, high hydrogen production efficiency, and a high hydrogen-to-electricity ratio. The hydrogen and electricity produced by the system are ideal green energy carriers that can be directly supplied to meet production and daily life needs. Powdered coal is fed into the gasifier and undergoes a partial gasification reaction with the gasifying agent, generating syngas and semi-coke products. These are then sent to a gasification product purification and reforming unit for purification and reforming, and to a pressurized oxygen-enriched combustion unit for combustion of the semi-coke, respectively.

[0044] Pure oxygen is provided by the air separation oxygen production unit, and carbon dioxide is provided by the carbon dioxide capture unit. The semi-coke combustion adopts pressurized circulating fluidized bed with pressurized oxygen-enriched combustion technology. The carbon dioxide capture cost produced by semi-coke combustion is low. Carbon dioxide is separated from hydrogen to obtain high-purity carbon dioxide, which is easy to achieve zero carbon dioxide emissions.

[0045] Secondly, the gasification product purification and reforming unit adopts steam methane reforming reaction and CO change reaction to make steam react with methane to generate CO, H2 and CO2, and adjusts the ratio of CO and H2 in the syngas after the reforming reaction to increase the H2 yield.

[0046] Finally, the outlet branch of the high-temperature heat exchanger in the steam Rankine cycle power generation unit is connected to the reforming reactor in the gasification product purification and reforming unit, providing it with high-temperature steam as the reaction gas, and using the waste heat of the syngas as the heat source to heat the steam participating in the reforming reaction.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A hydrogen-power cogeneration system coupling partial coal gasification and pressurized oxygen-enriched combustion of semi-coke, characterized in that, It includes an air separation oxygen production unit, a coal partial gasification unit, a semi-coke pressurized oxygen-enriched combustion unit, a gasification product purification and reforming unit, a pressure swing adsorption unit, a steam Rankine cycle power generation unit, and a CO2 capture unit. The air separation oxygen production unit supplies oxygen to the coal partial gasification unit and the semi-coke pressurized oxygen-enriched combustion unit. The coal partial gasification unit includes a pressurized circulating fluidized bed gasifier (6) and a gas-solid separation device (8). The coal partial gasification reaction occurs in the pressurized circulating fluidized bed gasifier (6). The reaction products of the pressurized circulating fluidized bed gasifier (6) are sent to the gas-solid separation device (8) for separation. The gas-solid separation device (8) sends the crude syngas to the waste heat recovery heat exchanger (9) in the gasification product purification and reforming unit, and sends the solid product semi-coke to the pressurized circulating fluidized bed combustion furnace (24) in the semi-coke pressurized oxygen-enriched combustion unit for combustion. The pressurized oxygen-enriched combustion unit for semi-coke also includes a cyclone separator (38). The pressurized circulating fluidized bed combustion furnace (24) obtains pure oxygen, semi-coke and recirculated flue gas for combustion reaction, and sends the combustion reaction products to the cyclone separator (38) for gas-solid separation. The cyclone separator (38) sends the separated solid waste to the medium-temperature superheater (26) in the steam Rankine cycle power generation unit, and sends the separated gaseous flue gas to the high-temperature superheater (27) in the steam Rankine cycle power generation unit. The pressurized oxygen-enriched semi-coke combustion unit provides high-temperature steam to the steam Rankine cycle power generation unit, and the steam Rankine cycle power generation unit provides low-temperature steam to the pressurized oxygen-enriched semi-coke combustion unit, thereby realizing steam circulation. The gasification product purification and reforming unit includes the waste heat recovery heat exchanger (9) and the reforming reactor (11). The waste heat recovery heat exchanger (9) recovers the waste heat from the crude syngas output by the gas-solid separation device (8) and uses the heat as the heat source for the reforming reactor (11). The high-temperature heat exchanger (32) in the steam Rankine cycle power generation unit inputs steam into the reforming reactor (11) as a reactant for the reforming reaction. The gasification product purification and reforming unit sends the clean syngas that has undergone reforming and change reactions to the pressure swing adsorption unit. The pressure swing adsorption unit separates and stores the hydrogen in the clean syngas and sends the syngas waste gas after removing the hydrogen to the CO2 capture unit. The CO2 capture unit includes a carbon dioxide heat exchanger (20), a carbon dioxide compressor (22), and a carbon dioxide storage device (23). The carbon dioxide heat exchanger (20) pressurizes a portion of the carbon dioxide and sends it to the carbon dioxide storage device (23) for storage, while sending another portion of the carbon dioxide to the pressurized circulating fluidized bed gasifier (6).

2. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 1, characterized in that, The coal gasification unit also includes a coal drying and purification device (7). After being dried and purified by the coal drying and purification device (7), the coal powder is sent to the pressurized circulating fluidized bed gasifier (6), and oxygen is supplied to the pressurized circulating fluidized bed gasifier (6) by the oxygen heater (5).

3. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 1, characterized in that, The feed inlet of the pressurized circulating fluidized bed combustion furnace (24) is connected to the oxygen heater (5) in the air separation oxygen production unit, the gas-solid separation device (8) in the coal partial gasification unit, and the economizer (35) in the steam Rankine cycle power generation unit, respectively, to obtain pure oxygen, semi-coke and recirculated flue gas for combustion reaction; The pressurized circulating fluidized bed combustion furnace (24) outputs all water vapor to the low-temperature superheater (25) in the steam Rankine cycle power generation unit and outputs all combustion reaction products to the cyclone separator (38).

4. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 3, characterized in that, The gasification product purification and reforming unit also includes a purification device (10) and a syngas heat exchanger (12). The outlet of the waste heat recovery heat exchanger (9) is connected to the inlet of the impurity removal device (10); The impurity removal device (10) desulfurizes the crude syngas, removes acidic gases from the crude syngas, and then transports the crude syngas to the reforming reactor (11). The outlet of the reforming reactor (11) is connected to the syngas heat exchanger (12), and the syngas heat exchanger (12) sends the clean syngas that has undergone the reforming reaction and the change reaction into the pressure swing adsorption device (13) in the pressure swing adsorption unit.

5. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 3, characterized in that, The steam Rankine cycle power generation unit also includes a high-pressure steam turbine (28), a medium-pressure steam turbine (29), a low-pressure steam turbine (30), a condenser (31), a low-temperature heat exchanger (33), a water pump (34), a low-temperature reheater (36), and a high-temperature reheater (37). The intermediate-temperature superheater (26) receives the high-temperature solid waste output from the cyclone separator (38) and the water vapor discharged from the low-temperature superheater (25); in the intermediate-temperature superheater (26), the solid waste heats the water vapor to make the water vapor superheated, and then the intermediate-temperature superheater (26) delivers high-temperature water vapor to the high-temperature superheater (27) and outputs solid waste to the low-temperature superheater (25); the solid waste is sent to the pressurized circulating fluidized bed combustion furnace (24) through the low-temperature superheater (25). The high-temperature superheater (27) uses the high-temperature gaseous flue gas provided by the cyclone separator (38) to further superheat the high-temperature steam input to the medium-temperature superheater (26), outputs high-temperature steam to the high-pressure steam turbine (28), and provides gaseous flue gas to the high-temperature reheater (37); The high-pressure steam turbine (28) supplies high-temperature steam to the high-temperature heat exchanger (32) and the low-temperature reheater (36); The low-temperature reheater (36) uses the high-temperature gaseous flue gas transported by the high-temperature reheater (37) to further heat the high-temperature steam passing through the low-temperature reheater (36), and transports the high-temperature steam to the high-temperature reheater (37). The high-temperature reheater (37) provides reheated steam to the medium-pressure steam turbine (29) and outputs gaseous flue gas to the low-temperature reheater (36); One branch of the medium-pressure steam turbine (29) is connected to the low-temperature heat exchanger (33), and the other branch is connected to the low-pressure steam turbine (30). The outlet of the low-pressure steam turbine (30) is connected to the inlet of the condenser (31). Water vapor is cooled into liquid in the condenser (31) and sent to the low-temperature heat exchanger (33) by the water pump (34) to form a water vapor cycle; the water pump (34) can also directly supply water to the low-temperature heat exchanger (33).

6. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 5, characterized in that, The steam expands in the high-pressure steam turbine (28) to do work and output electricity. The steam pressure at the outlet of the high-pressure steam turbine (28) is 4 MPa. Inside the high-temperature reheater (37), the gaseous flue gas reheats the water vapor, and the water vapor outlet of the high-temperature reheater (37) is at 560°C and 4MPa. The steam expands in the medium-pressure steam turbine (29) to do work and output electricity. The steam pressure at the outlet of the medium-pressure steam turbine (29) is 2 MPa. Water vapor expands in the low-pressure steam turbine (30) to do work and output electricity. The water vapor state at the outlet of the low-pressure steam turbine (30) is 0.75 MPa.

7. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 4, characterized in that, The pressure swing adsorption unit also includes a hydrogen compressor (14), a hydrogen storage device (15), and a waste gas heat exchanger (16). The pressure swing adsorption device (13) separates hydrogen from the clean synthesis gas and sends it to the hydrogen compressor (14) for pressurization. The hydrogen compressor (14) then sends the pressurized hydrogen to the hydrogen storage device (15) for storage. The synthesis gas waste gas after hydrogen removal is sent to the waste gas heat exchanger (16).

8. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 7, characterized in that, The CO2 capture unit also includes a flash reactor (17), a multi-stage exhaust gas compressor (18), an exhaust gas purification device (19), and an exhaust gas distillation tower (21). The waste gas heat exchanger (16) sends the waste gas into the flash reactor (17). After the flash reactor (17) discharges the moisture in the waste gas, the dry waste gas is sent to the waste gas multi-stage compressor (18). The waste gas multi-stage compressor (18) pressurizes the dry waste gas and sends it to the waste gas purification device (19). After washing, NO is converted into HNO3 in the NOx removal process, and carbon dioxide is separated from the remaining acidic solution. The waste gas purification device (19) sends the washed waste gas into the carbon dioxide heat exchanger (20), and then through the carbon dioxide heat exchanger (20) it is transported to the waste gas distillation tower (21). The waste gas distillation tower (21) separates the input waste gas into CO2 and other gases, which are then sent into the carbon dioxide heat exchanger (20).

9. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 1, characterized in that, The air separation oxygen production unit includes an air compressor (1), an air heat exchanger (2), an air low-pressure distillation tower (3), an air high-pressure distillation tower (4), and an oxygen heater (5). After being cooled by the air compressor (1), the air is sent to the air heat exchanger (2) and then sent to the low-pressure air distillation tower (3) and the high-pressure air distillation tower (4) respectively. The air is distilled into O2 and N2 in the distillation tower. The high-pressure air distillation tower (4) outputs oxygen and nitrogen to the low-pressure air distillation tower (3); the low-pressure air distillation tower (3) supplies oxygen and nitrogen to the air heat exchanger (2) respectively; The air heat exchanger (2) uses air to separate nitrogen and cool and separate oxygen to obtain high-purity oxygen, which is then sent to the oxygen heater (5). After the oxygen heater (5) heats the oxygen, it is sent to the coal partial gasification unit and the semi-coke pressurized oxygen-enriched combustion unit, respectively.

10. The hydrogen-power cogeneration system coupled with partial coal gasification and pressurized oxygen-enriched combustion of semi-coke according to claim 2, characterized in that, The operating temperature of the pressurized circulating fluidized bed gasifier (6) is controlled between 750°C and 1150°C, and the operating pressure is controlled between 1MPa and 3MPa.

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