IGCC (integrated gasification combined cycle) system coupled with biomass near-zero emission high-purity CO2 trapping and working method thereof

Abstract

The invention discloses an IGCC (integrated gasification combined cycle) system coupled with biomass near-zero emission and high-purity CO2 capture and a working method thereof, belongs to the field of coal gasification combined cycle power generation coupled with biomass, and particularly relates to the IGCC system coupled with biomass near-zero emission and high-purity CO2 capture and the working method thereof. The problems that in an existing IGCC system, the carbon dioxide capture rate is low, the power generation efficiency is reduced due to large energy consumption, and a large amount of nitrogen generated in the oxygen taking process is difficult to effectively utilize are solved. The system comprises an air separation device, a gasification furnace, a sensible heat recovery device, a purification device, a gas power generation unit, a waste heat recovery unit, a steam power generation unit, a biomass fermentation device, a methane reforming unit, an adsorption separation unit and an ammonia synthesis tower. According to the integrated coal gasification combined cycle power generation system based on CO2 trapping after combustion and an oxygen-enriched combustion technology, a biomass ammonia synthesis process is introduced, H2 and CO are generated through biomass fermentation and reforming, and the system efficiency is improved while N2 is utilized.

Description

Technical Field

[0001] The present invention belongs to the field of biomass-coupled coal gasification combined cycle power generation, and specifically relates to an IGCC system coupled with biomass near-zero emission high-purity CO2 capture and a working method thereof. Background Art

[0002] my country's energy resource endowment is characterized by low oil and limited natural gas resources, and abundant coal. Coal has long dominated my country's energy consumption structure, making the efficient and clean utilization of coal resources crucial for ensuring a secure and stable energy supply. Coal resources are abundant and will remain an indispensable component of my country's energy system, both now and for a long time to come. However, traditional coal utilization is often accompanied by numerous issues, including low energy efficiency and high pollutant emissions. This is neither in line with my country's "dual carbon" goals nor conducive to ecological and environmental protection.

[0003] The emergence of integrated gasification combined cycle (IGCC) technology offers a promising solution to these challenges. It innovatively combines clean coal gasification with gas-steam combined cycle power generation. Gasification converts coal into syngas (primarily containing carbon monoxide and hydrogen), achieving clean coal conversion and providing a suitable fuel for subsequent power generation. Furthermore, the IGCC utilizes the high-temperature combustion gas generated by the syngas combustion to drive a gas turbine for power generation. The high-temperature exhaust from the gas turbine is then used to generate steam, which in turn drives a steam turbine for further power generation. This combined cycle significantly improves power generation efficiency, producing more electricity with the same coal resource input compared to traditional coal-fired power generation. Furthermore, by employing a series of advanced pollution control technologies in both the gasification and power generation stages, IGCC effectively reduces emissions of pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter, mitigating environmental pollution at the source. This approach, while meeting energy supply needs, also balances environmental protection and plays a significant role in optimizing my country's energy structure and promoting low-carbon development.

[0004] In the quest for low-carbon or even zero-carbon power generation, existing near-zero or zero-emission IGCC systems employ different process approaches for CO2 capture and address their respective challenges. One common approach involves introducing a shift process, utilizing a specific chemical reaction to convert carbon monoxide (CO) produced by coal gasification into carbon dioxide (CO2), which is then captured. This approach can achieve a CO2 capture rate of approximately 90%, which, to a certain extent, helps reduce the amount of CO2 emitted into the atmosphere and promotes the development of a low-carbon power generation process.

[0005] Another method is to use an oxygen-enriched combustion method based on cryogenic air separation. The principle of this method is to produce high-purity oxygen through cryogenic air separation technology, so that coal can be burned in an oxygen-rich environment to produce flue gas rich in carbon dioxide, which is more conducive to the capture of carbon dioxide and can theoretically achieve a higher carbon dioxide capture rate. However, this method is not perfect and has obvious disadvantages. In order to produce a large amount of high-purity oxygen, the cryogenic air separation unit needs to consume a lot of energy, which significantly increases the energy consumption of the entire IGCC system, thereby reducing the power generation efficiency of the system. Moreover, in the process of producing oxygen, a large amount of nitrogen (N2) will be produced. These nitrogen gases are often difficult to find effective ways to utilize in the current process links. They can only be discharged as useless gases or require additional treatment measures, further increasing the complexity and cost of the system. Summary of the Invention

[0006] The present invention aims to solve the problems in existing IGCC systems of low carbon dioxide capture rate, high energy consumption leading to reduced power generation efficiency, and the large amount of nitrogen generated during oxygen extraction that is difficult to effectively utilize. The present invention provides an IGCC system coupled with biomass near-zero emission high-purity CO2 capture and its operating method.

[0007] An IGCC system coupled with biomass near-zero emission high-purity CO2 capture includes an air separation unit, a gasifier, a sensible heat recovery unit, a purification unit, a gas power generation unit, a waste heat recovery unit, a steam power generation unit, a biomass fermentation unit, a methane reforming unit, an adsorption separation unit, and an ammonia synthesis tower;

[0008] The first oxygen outlet of the air separation unit is connected to the oxygen inlet of the gasifier, the second oxygen outlet of the air separation unit is connected to the oxygen inlet of the gas-fired power generation unit, and the nitrogen outlet of the air separation unit is connected to the nitrogen inlet of the ammonia synthesis tower; the gasifier is provided with a pulverized coal input pipeline, the raw coal gas outlet of the gasifier is connected to the raw coal gas inlet of the sensible heat recovery unit; the high-temperature steam outlet of the sensible heat recovery unit is connected to the first high-temperature steam inlet of the steam power generation unit, and the raw coal gas outlet of the sensible heat recovery unit is connected to the raw coal gas inlet of the purification device; the purified gas outlet of the purification device is connected to the purified gas inlet of the gas-fired power generation unit; the high-temperature mixed gas outlet of the gas-fired power generation unit is connected to the high-temperature mixed gas inlet of the waste heat recovery unit; the carbon dioxide produced by the waste heat recovery unit It is divided into three routes, one is connected to the pulverized coal input pipeline, one is reinjected into the oxygen inlet of the gas-fired power generation unit, and one is stored and recovered; the first high-temperature steam outlet of the waste heat recovery unit is connected to the high-temperature steam inlet of the methane reforming unit, and the second high-temperature steam outlet of the waste heat recovery unit is connected to the second high-temperature steam inlet of the steam power generation unit; the water supply outlet of the steam power generation unit is connected to the water supply inlet of the waste heat recovery unit; the methane outlet of the biomass fermentation device is connected to the methane inlet of the methane reforming unit; the mixed gas outlet of the methane reforming unit is connected to the mixed gas inlet of the adsorption separation unit; the carbon monoxide outlet of the adsorption separation unit is connected to the carbon monoxide inlet of the gas-fired power generation unit, and the hydrogen outlet of the adsorption separation unit is connected to the hydrogen inlet of the ammonia synthesis tower.

[0009] A method for operating an IGCC system coupled with biomass near-zero emission high-purity CO2 capture is carried out in the following steps:

[0010] The oxygen produced by the air separation unit is output in two ways, one to the gasifier and the other to the gas power generation unit. The nitrogen produced by the air separation unit enters the ammonia synthesis tower.

[0011] The carbon dioxide produced by the waste heat recovery unit is divided into three paths: one is connected to the pulverized coal input pipeline, one is reinjected into the oxygen inlet of the gas-fired power generation unit, and one is stored and recovered;

[0012] The steam from the waste heat recovery unit is divided into two paths, one entering the methane reforming unit and the other entering the steam power generation unit;

[0013] The raw coal gas generated by the gasifier enters the sensible heat recovery device for heat exchange. The high-temperature steam generated by the sensible heat recovery device is passed into the steam power generation unit to generate electricity. The raw coal gas output by the sensible heat recovery device enters the purification device for dust removal, desulfurization, and denitrification. The purified H2 and CO mixture enters the gas power generation unit.

[0014] The high-temperature exhaust CO2 and high-temperature steam mixture generated by the gas-fired power generation unit enters the waste heat recovery unit, and the electricity generated by the gas-fired power generation unit is integrated into the power grid;

[0015] The CH4 produced by the biomass fermentation device enters the methane reforming unit, the H2 and CO mixture produced by the methane reforming unit enters the adsorption separation unit, the CO produced by the adsorption separation unit enters the gas power generation unit for combustion, the H2 produced by the adsorption separation unit enters the ammonia synthesis tower, and the NH3 produced by the ammonia synthesis tower is stored and recovered.

[0016] Advantages of the present invention:

[0017] The present invention uses CO2 to transport pulverized coal to the gasifier and simultaneously uses CO2 to reinject into the gas-fired power generation unit. Compared with N2 or air transportation, this greatly reduces the generation of nitrogen oxides during the gasification and combustion processes and can also seal part of the CO2 within the system.

[0018] The biomass ammonia synthesis process is coupled to utilize the N2 produced in the air separation process. The CO produced in the biomass ammonia synthesis process can be used for gas-fired power generation. The high-temperature gas generated by the gas-fired power generation unit is passed through the waste heat recovery device to produce high-temperature steam that can be used for methane reforming in the biomass ammonia synthesis process, thereby improving the material utilization rate of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the IGCC system coupled with biomass near-zero emission high-purity CO2 capture. DETAILED DESCRIPTION

[0020] Specific embodiment 1: This embodiment is described with reference to the accompanying drawings. In this embodiment, an IGCC system coupled with biomass near-zero emission high-purity CO2 capture includes an air separation unit 1, a gasifier 2, a sensible heat recovery unit 3, a purification unit 4, a gas power generation unit 5, a waste heat recovery unit 6, a steam power generation unit 7, a biomass fermentation unit 8, a methane reforming unit 9, an adsorption separation unit 10 and an ammonia synthesis tower 11;

[0021] The first oxygen outlet of the air separation unit 1 is connected to the oxygen inlet of the gasifier 2, the second oxygen outlet of the air separation unit 1 is connected to the oxygen inlet of the gas power generation unit 5, and the nitrogen outlet of the air separation unit 1 is connected to the nitrogen inlet of the ammonia synthesis tower 11; the gasifier 2 is provided with a pulverized coal input pipeline, the raw gas outlet of the gasifier 2 is connected to the raw gas inlet of the sensible heat recovery device 3; the high-temperature steam outlet of the sensible heat recovery device 3 is connected to the first high-temperature steam inlet of the steam power generation unit 7, and the raw gas outlet of the sensible heat recovery device 3 is connected to the raw gas inlet of the purification device 4; the purified gas outlet of the purification device 4 is connected to the purified gas inlet of the gas power generation unit 5; the high-temperature mixed gas outlet of the gas power generation unit 5 is connected to the high-temperature mixed gas inlet of the waste heat recovery unit 6; the carbon dioxide produced by the waste heat recovery unit 6 It is divided into three routes, one is connected to the pulverized coal input pipeline, one is reinjected into the oxygen inlet of the gas-fired power generation unit 5, and one is stored and recovered; the first high-temperature steam outlet of the waste heat recovery unit 6 is connected to the high-temperature steam inlet of the methane reforming unit 9, and the second high-temperature steam outlet of the waste heat recovery unit 6 is connected to the second high-temperature steam inlet of the steam power generation unit 7; the water supply outlet of the steam power generation unit 7 is connected to the water supply inlet of the waste heat recovery unit 6; the methane outlet of the biomass fermentation device 8 is connected to the methane inlet of the methane reforming unit 9; the mixed gas outlet of the methane reforming unit 9 is connected to the mixed gas inlet of the adsorption separation unit 10; the carbon monoxide outlet of the adsorption separation unit 10 is connected to the carbon monoxide inlet of the gas-fired power generation unit 5, and the hydrogen outlet of the adsorption separation unit 10 is connected to the hydrogen inlet of the ammonia synthesis tower 11.

[0022] This embodiment is based on an integrated coal gasification combined cycle power generation system with post-combustion CO2 capture and oxygen-enriched combustion technology, and introduces a biomass ammonia synthesis process to produce H2 and CO through biomass fermentation and reforming. The H2 and N2 produced by air separation enter the ammonia synthesis tower to synthesize NH3, and the CO is injected into the gas turbine for combustion and power generation, thereby utilizing part of the N2 while improving the system efficiency.

[0023] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the electric energy generated by the gas power generation unit 5 is fed into the power grid. Other aspects are the same as specific embodiment 1.

[0024] Specific embodiment 3: This embodiment differs from specific embodiment 1 in that the electric energy generated by the steam power generation unit 7 is fed into the power grid. Other aspects are the same as specific embodiment 1.

[0025] Specific embodiment 4: This embodiment differs from specific embodiment 1 in that the ammonia gas produced by the ammonia synthesis tower 11 is stored and recovered. Other aspects are the same as specific embodiment 1.

[0026] Specific embodiment 5: A working method of an IGCC system coupled with biomass near-zero emission high-purity CO2 capture, which is carried out in the following steps:

[0027] The oxygen produced by the air separation unit 1 is output in two ways, one way enters the gasifier 2 and the other way enters the gas power generation unit 5. The nitrogen produced by the air separation unit 1 enters the ammonia synthesis tower 11;

[0028] The carbon dioxide produced by the waste heat recovery unit 6 is divided into three paths: one path is connected to the pulverized coal input pipeline, one path is reinjected into the oxygen inlet of the gas-fired power generation unit 5, and one path is stored and recovered;

[0029] The steam from the waste heat recovery unit 6 is divided into two paths, one path enters the methane reforming unit 9, and the other path enters the steam power generation unit 7;

[0030] The raw coal gas generated by the gasifier 2 enters the sensible heat recovery device 3 for heat exchange. The high-temperature steam generated by the sensible heat recovery device 3 is passed into the steam power generation unit 7 to generate electricity. The raw coal gas output by the sensible heat recovery device 3 enters the purification device 4 for dust removal, desulfurization, and denitrification. The purified H2 and CO mixture enters the gas power generation unit 5.

[0031] The high-temperature exhaust CO2 and high-temperature steam mixture generated by the gas-fired power generation unit 5 enters the waste heat recovery unit 6, and the electricity generated by the gas-fired power generation unit 5 is integrated into the power grid;

[0032] The CH4 produced by the biomass fermentation device 8 enters the methane reforming unit 9, the H2 and CO mixture produced by the methane reforming unit 9 enters the adsorption separation unit 10, the CO produced by the adsorption separation unit 10 enters the gas power generation unit for combustion, the H2 produced by the adsorption separation unit 10 enters the ammonia synthesis tower 11, and the NH3 produced by the ammonia synthesis tower 11 is stored and recovered.

[0033] Specific embodiment 6: This embodiment differs from specific embodiment 5 in that the ammonia produced by the ammonia synthesis tower 11 is stored and recovered. The crude coal gas output by the sensible heat recovery device 3 has a composition of 55% CO, 25% H2, 7% CO2, and 13% impurity components. All other aspects are the same as specific embodiment 5.

[0034] Specific embodiment 7: This embodiment differs from specific embodiment 6 in that the impurity gas components are N2, H2S, COS, and CH4. Other aspects are the same as specific embodiment 6.

[0035] Specific embodiment eight: This embodiment differs from specific embodiment five in that the purified H2 and CO mixture comprises 62% CO, 28% H2, 8% CO2, 0.5% N2, and 1.5% CH4. Other aspects are the same as specific embodiment five.

[0036] Specific embodiment 9: This embodiment differs from specific embodiment 5 in that, based on the calculation that the adsorption separation unit 10 provides 20% CO, the purity of CO2 output by the waste heat recovery unit 6 can reach 99.56%. Other aspects are the same as specific embodiment 5.

[0037] The following examples are used to verify the technical effects of the present invention:

[0038] Example: A method for operating an IGCC system coupled with biomass near-zero emission high-purity CO2 capture is carried out in the following steps:

[0039] The oxygen produced by the air separation unit 1 is output in two ways, one way enters the gasifier 2 and the other way enters the gas power generation unit 5. The nitrogen produced by the air separation unit 1 enters the ammonia synthesis tower 11;

[0040] The carbon dioxide produced by the waste heat recovery unit 6 is divided into three paths: one path is connected to the pulverized coal input pipeline, one path is reinjected into the oxygen inlet of the gas-fired power generation unit 5, and one path is stored and recovered;

[0041] The steam from the waste heat recovery unit 6 is divided into two paths, one path enters the methane reforming unit 9, and the other path enters the steam power generation unit 7;

[0042] The raw coal gas generated by the gasifier 2 enters the sensible heat recovery device 3 for heat exchange. The high-temperature steam generated by the sensible heat recovery device 3 is passed into the steam power generation unit 7 to generate electricity. The raw coal gas output by the sensible heat recovery device 3 enters the purification device 4 for dust removal, desulfurization, and denitrification. The purified H2 and CO mixture enters the gas power generation unit 5.

[0043] The high-temperature exhaust CO2 and high-temperature steam mixture generated by the gas-fired power generation unit 5 enters the waste heat recovery unit 6, and the electricity generated by the gas-fired power generation unit 5 is integrated into the power grid;

[0044] The CH4 produced by the biomass fermentation device 8 enters the methane reforming unit 9, the H2 and CO mixture produced by the methane reforming unit 9 enters the adsorption separation unit 10, the CO produced by the adsorption separation unit 10 enters the gas power generation unit for combustion, the H2 produced by the adsorption separation unit 10 enters the ammonia synthesis tower 11, and the NH3 produced by the ammonia synthesis tower 11 is stored and recovered.

[0045] The ammonia produced by the ammonia synthesis tower 11 is stored and recovered. The raw coal gas output by the sensible heat recovery device 3 has a composition of 55% CO, 25% H2, 7% CO2, and 13% impurity gas.

[0046] The impurity gas components are N2, H2S, COS, and CH4.

[0047] The purified H2 and CO mixture consists of 62% CO, 28% H2, 8% CO2, 0.5% N2, and 1.5% CH4. Based on the adsorption separation unit 10 providing 20% ​​CO, the CO2 output by the waste heat recovery unit 6 has a purity of up to 99.56%.

[0048] This embodiment uses CO2 to transport pulverized coal to the gasifier and simultaneously uses CO2 to be reinjected into the gas-fired power generation unit. Compared with N2 or air transportation, this greatly reduces the generation of nitrogen oxides during the gasification and combustion processes and can also seal some CO2 within the system.

[0049] The biomass ammonia synthesis process is coupled to utilize the N2 produced in the air separation process. The CO produced in the biomass ammonia synthesis process can be used for gas-fired power generation. The high-temperature gas generated by the gas-fired power generation unit is passed through the waste heat recovery device to produce high-temperature steam that can be used for methane reforming in the biomass ammonia synthesis process, thereby improving the material utilization rate of the system.

Claims

1. An IGCC system coupled with zero-emission biomass high-purity CO2 capture, characterized in that The IGCC system coupled with biomass zero-emission high-purity CO2 capture includes an air separation unit (1), a gasifier (2), a sensible heat recovery unit (3), a purification unit (4), a gas power generation unit (5), a waste heat recovery unit (6), a steam power generation unit (7), a biomass fermentation unit (8), a methane reforming unit (9), an adsorption separation unit (10) and an ammonia synthesis tower (11); The first oxygen outlet of the air separation device (1) is connected to the oxygen inlet of the gasifier (2), the second oxygen outlet of the air separation device (1) is connected to the oxygen inlet of the gas power generation unit (5), and the nitrogen outlet of the air separation device (1) is connected to the nitrogen inlet of the ammonia synthesis tower (11); the gasifier (2) is provided with a pulverized coal input pipeline, the raw coal gas outlet of the gasifier (2) is connected to the raw coal gas inlet of the sensible heat recovery device (3); the high-temperature steam outlet of the sensible heat recovery device (3) is connected to the first high-temperature steam inlet of the steam power generation unit (7), and the raw coal gas outlet of the sensible heat recovery device (3) is connected to the raw coal gas inlet of the purification device (4); the purified gas outlet of the purification device (4) is connected to the purified gas inlet of the gas power generation unit (5); the high-temperature mixed gas outlet of the gas power generation unit (5) is connected to the high-temperature mixed gas inlet of the waste heat recovery unit (6); the two gases produced by the waste heat recovery unit (6) are The carbon monoxide is divided into three paths, one path is connected to the coal powder input pipeline, one path is reinjected into the oxygen inlet of the gas power generation unit (5), and one path is stored and recovered; the first high-temperature steam outlet of the waste heat recovery unit (6) is connected to the high-temperature steam inlet of the methane reforming unit (9), and the second high-temperature steam outlet of the waste heat recovery unit (6) is connected to the second high-temperature steam inlet of the steam power generation unit (7); the water supply outlet of the steam power generation unit (7) is connected to the water supply inlet of the waste heat recovery unit (6); the methane outlet of the biomass fermentation device (8) is connected to the methane inlet of the methane reforming unit (9); the mixed gas outlet of the methane reforming unit (9) is connected to the mixed gas inlet of the adsorption separation unit (10); the carbon monoxide outlet of the adsorption separation unit (10) is connected to the carbon monoxide inlet of the gas power generation unit (5), and the hydrogen outlet of the adsorption separation unit (10) is connected to the hydrogen inlet of the ammonia synthesis tower (11).

2. The IGCC system coupled with biomass zero emission high purity CO2 capture according to claim 1 is characterized in that The electric energy generated by the gas power generation unit (5) is fed into the power grid.

3. The IGCC system coupled with biomass zero emission high purity CO2 capture according to claim 1 is characterized in that The electric energy generated by the steam power generation unit (7) is fed into the power grid.

4. The IGCC system coupled with biomass zero-emission high-purity CO2 capture according to claim 1 is characterized in that The ammonia gas produced by the ammonia synthesis tower (11) is stored and recovered.

5. The method for operating an IGCC system coupled with biomass zero-emission high-purity CO2 capture as claimed in claim 1, characterized in that It is carried out in the following steps: The oxygen generated by the air separation device (1) is output in two ways, one way enters the gasification furnace (2), and the other way enters the gas power generation unit (5); the nitrogen generated by the air separation device (1) enters the ammonia synthesis tower (11); The carbon dioxide produced by the waste heat recovery unit (6) is divided into three paths, one path is connected to the coal powder input pipeline, one path is reinjected into the oxygen inlet of the gas power generation unit (5), and one path is stored and recovered; The steam from the waste heat recovery unit (6) is divided into two paths, one path entering the methane reforming unit (9) and the other path entering the steam power generation unit (7); The raw coal gas generated by the gasifier (2) enters the sensible heat recovery device (3) for heat exchange, the high-temperature steam generated by the sensible heat recovery device (3) is passed into the steam power generation unit (7) to generate electric energy, the raw coal gas output by the sensible heat recovery device (3) enters the purification device (4) for dust removal, desulfurization and denitrification, and the purified H2 and CO mixture enters the gas power generation unit (5); The high-temperature tail gas CO2 and high-temperature steam mixture generated by the gas power generation unit (5) enters the waste heat recovery unit (6), and the electric energy generated by the gas power generation unit (5) is connected to the power grid; The CH4 generated by the biomass fermentation device (8) enters the methane reforming unit (9), the H2 and CO mixture generated by the methane reforming unit (9) enters the adsorption separation unit (10), the CO generated by the adsorption separation unit (10) enters the gas power generation unit for combustion, the H2 generated by the adsorption separation unit (10) enters the ammonia synthesis tower (11), and the NH3 generated by the ammonia synthesis tower (11) is stored and recovered.

6. The method of claim 5 for operating an IGCC system coupled with zero-emission biomass high-purity CO2 capture, characterized in that The raw coal gas outputted by the sensible heat recovery device (3) has components of 55% CO, 25% H2, 7% CO2, and 13% impurity gas components.

7. The method of claim 6 for operating an IGCC system coupled with zero-emission high-purity CO2 capture from biomass, characterized in that The impurity gas components are N2, H2S, COS, and CH4.

8. The method of claim 5 for operating an IGCC system coupled with zero-emission biomass high-purity CO2 capture, characterized in that The purified H2 and CO mixture consists of 62% CO, 28% H2, 8% CO2, 0.5% N2 and 1.5% CH4.

9. The method of claim 5 for operating an IGCC system coupled with zero-emission biomass high-purity CO2 capture, characterized in that Based on the calculation that the adsorption separation unit (10) provides 20% of CO, the purity of CO2 output by the waste heat recovery unit (6) can reach 99.56%.

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