An IGCC system coupled with near-zero emission high-purity CO2 capture from biomass and its working method

Abstract

The application relates to an IGCC system coupled with biomass and near-zero emission high-purity CO2 capture and a working method thereof, and belongs to the field of coal gasification combined cycle power generation coupled with biomass, in particular to an IGCC system coupled with biomass and near-zero emission high-purity CO2 capture and a working method thereof. The application is used for solving the problems that the existing IGCC system has low CO2 capture rate, high energy consumption, low power generation efficiency, and a large amount of nitrogen generated in the oxygen taking process and difficult to effectively utilize. The application 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. The application is based on the overall coal gasification combined cycle power generation system of post-combustion CO2 capture and oxygen-enriched combustion technology, introduces a biomass ammonia synthesis process, generates H2 and CO through biomass fermentation and reforming, utilizes N2, and improves the system efficiency.

Description

Technical Field

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

[0002] my country's energy resources are characterized by being poor in oil and gas but abundant in coal. For a long time, coal has dominated my country's energy consumption structure, making the efficient and clean utilization of coal resources crucial to ensuring a secure and stable energy supply. Coal resources are plentiful and will remain an indispensable and important component of my country's energy system for the foreseeable future. However, traditional coal utilization methods often involve low energy efficiency and high pollutant emissions, which are 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) power generation technology offers a highly promising approach to solving the aforementioned problems. It innovatively combines clean coal gasification technology with gas-steam combined cycle power generation. On one hand, coal gasification converts coal into syngas (primarily containing carbon monoxide and hydrogen), achieving clean coal conversion and providing suitable fuel for subsequent power generation. On the other hand, gas-steam combined cycle power generation fully utilizes the high-temperature gas produced by syngas combustion to drive a gas turbine for power generation, and then uses the high-temperature exhaust gas from the gas turbine 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. Simultaneously, the adoption of advanced pollution control technologies in both the gasification and power generation stages effectively reduces emissions of pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter, reducing environmental pollution at its source. This approach balances energy supply needs with environmental protection, holding significant importance for optimizing my country's energy structure and promoting low-carbon development.

[0004] In the exploration of achieving low-carbon or even zero-carbon power generation, existing near-zero or zero-emission IGCC systems employ different technological approaches and face corresponding challenges in carbon dioxide capture. One common approach is to introduce a shift conversion process, utilizing specific chemical reactions to convert carbon monoxide (CO) produced during coal gasification into carbon dioxide (CO2), thereby achieving carbon dioxide capture. This method can achieve a carbon dioxide capture rate of approximately 90%, which helps reduce the amount of carbon dioxide emitted into the atmosphere and promotes the development of low-carbon power generation processes.

[0005] Another method is oxy-fuel combustion based on cryogenic air separation. This method uses cryogenic air separation technology to produce high-purity oxygen, which is then burned in an oxygen-rich environment to generate carbon dioxide-rich flue gas, thus improving carbon dioxide capture and theoretically achieving a higher capture rate. However, this method is not without its drawbacks. To produce large quantities of high-purity oxygen, the cryogenic air separation unit consumes a significant amount of energy, significantly increasing the energy consumption of the entire IGCC system and consequently reducing its power generation efficiency. Furthermore, the oxygen production process generates large amounts of nitrogen (N2), which is often difficult to utilize effectively in current processes and must either be emitted as waste gas or require additional treatment, further increasing the system's complexity and cost. Summary of the Invention

[0006] This invention addresses the problems of low carbon dioxide capture rate, high energy consumption leading to reduced power generation efficiency, and the difficulty in effectively utilizing the large amount of nitrogen generated during oxygen extraction in existing IGCC systems. It provides an IGCC system coupled with near-zero emission high-purity CO2 capture from biomass and its operating method.

[0007] An IGCC system coupled with near-zero emission high-purity CO2 capture from biomass includes an air separation unit, a gasifier, a sensible heat recovery unit, a purification unit, a gas-fired 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 equipped with a pulverized coal input pipeline, and the crude gas outlet of the gasifier is connected to the crude 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 crude gas outlet of the sensible heat recovery unit is connected to the crude gas inlet of the purification unit. The purified gas outlet of the purification unit 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 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, and one path 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 feedwater outlet of the steam power generation unit is connected to the feedwater 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 near-zero emission high-purity CO2 capture from biomass, comprising the following steps:

[0010] The oxygen produced by the air separation unit is output in two ways: one goes into the gasifier and the other goes into the gasification power generation unit. The nitrogen produced by the air separation unit goes into the ammonia synthesis tower.

[0011] The carbon dioxide produced by the waste heat recovery unit 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, and the other path is stored and recovered.

[0012] The steam from the waste heat recovery unit is split into two paths: one path goes into the methane reforming unit, and the other path goes into the steam power generation unit.

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

[0014] The high-temperature exhaust gas 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 fed into the power grid.

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

[0016] Advantages of this invention:

[0017] This invention uses CO2 to transport pulverized coal to the gasifier and CO2 is 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 at the same time, it can keep some of the CO2 within the system.

[0018] The system is coupled with a biomass ammonia synthesis process to utilize the N2 generated during the air separation process. The CO generated during 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, after passing through a waste heat recovery device, produces high-temperature steam that can be used for methane reforming during the biomass ammonia synthesis process, thereby improving the system's material utilization rate. Attached Figure Description

[0019] Figure 1 A schematic diagram of the IGCC system for capturing near-zero emission high-purity CO2 from biomass. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method is described in conjunction with the accompanying drawings. This implementation method is an IGCC system coupled with near-zero emission high-purity CO2 capture of biomass, which includes an air separation unit 1, a gasifier 2, a sensible heat recovery unit 3, a purification unit 4, a gas-fired 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-fired 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 equipped with a pulverized coal input pipeline, and the crude gas outlet of the gasifier 2 is connected to the crude 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 crude gas outlet of the sensible heat recovery device 3 is connected to the crude 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-fired power generation unit 5. The high-temperature mixed gas outlet of the gas-fired 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 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; 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 implementation method is based on a combined cycle gasification power generation system using post-combustion CO2 capture and oxygen-enriched combustion technology. It introduces a biomass ammonia synthesis process, which produces 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 to generate electricity. This method utilizes some of the N2 while improving system efficiency.

[0023] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the electrical energy generated by the gas-fired power generation unit 5 is fed into the power grid. Everything else is the same as in Specific Implementation Method One.

[0024] Specific Implementation Method Three: The difference between this implementation method and Specific Implementation Method One is that the electrical energy generated by the steam power generation unit 7 is fed into the power grid. Everything else is the same as in Specific Implementation Method One.

[0025] Specific Implementation Method Four: The difference between this implementation method and Specific Implementation Method One is that the ammonia gas produced by the ammonia synthesis tower 11 is stored and recovered. Everything else is the same as in Specific Implementation Method One.

[0026] Specific Implementation Method 5: A working method for an IGCC system coupled with near-zero emission high-purity CO2 capture from biomass, which is carried out according to the following steps:

[0027] The oxygen produced by the air separation unit 1 is output in two ways: one goes into the gasifier 2 and the other goes into the gasification power generation unit 5. The nitrogen produced by the air separation unit 1 goes into 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 the other path is stored and recovered.

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

[0030] The crude coal gas produced by gasifier 2 enters the sensible heat recovery device 3 for heat exchange. The high-temperature steam produced by the sensible heat recovery device 3 is fed into the steam power generation unit 7 to generate electricity. The crude coal gas output from 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-fired power generation unit 5.

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

[0032] The CH4 produced by the biomass fermentation unit 8 enters the methane reforming unit 9. The mixture of H2 and CO 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. The NH3 produced by the ammonia synthesis tower 11 is stored and recovered.

[0033] Specific Implementation Method Six: The difference between this implementation method and Specific Implementation Method Five is that the ammonia gas 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% impurities. Everything else is the same as in Specific Implementation Method Five.

[0034] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Method Six is ​​that the impurity gas components are N2, H2S, COS, and CH4. Everything else is the same as in Specific Implementation Method Six.

[0035] Specific Implementation Method Eight: The difference between this implementation method and Specific Implementation Method Five is that the purified H2 and CO mixture consists of 62% CO, 28% H2, 8% CO2, 0.5% N2, and 1.5% CH4. Everything else is the same as in Specific Implementation Method Five.

[0036] Specific Implementation Method Nine: The difference between this implementation method and Specific Implementation Method Five is that, based on the adsorption separation unit 10 providing 20% ​​CO, the purity of CO2 output by the waste heat recovery unit 6 can reach 99.56%. Everything else is the same as in Specific Implementation Method Five.

[0037] The technical effects of the present invention are verified using the following embodiments:

[0038] Example: A method for operating an IGCC system coupled with near-zero emission high-purity CO2 capture from biomass, comprising the following steps:

[0039] The oxygen produced by the air separation unit 1 is output in two ways: one goes into the gasifier 2 and the other goes into the gasification power generation unit 5. The nitrogen produced by the air separation unit 1 goes into 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 the other path is stored and recovered.

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

[0042] The crude coal gas produced by gasifier 2 enters the sensible heat recovery device 3 for heat exchange. The high-temperature steam produced by the sensible heat recovery device 3 is fed into the steam power generation unit 7 to generate electricity. The crude coal gas output from 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-fired power generation unit 5.

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

[0044] The CH4 produced by the biomass fermentation unit 8 enters the methane reforming unit 9. The mixture of H2 and CO 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. 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 crude coal gas output by the sensible heat recovery unit 3 has a composition of 55% CO, 25% H2, 7% CO2, and 13% impurities.

[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 purity output from the waste heat recovery unit 6 can reach 99.56%.

[0048] This embodiment uses CO2 to transport pulverized coal to the gasifier and CO2 is 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 at the same time, it can keep some of the CO2 within the system.

[0049] The system is coupled with a biomass ammonia synthesis process to utilize the N2 generated during the air separation process. The CO generated during 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, after passing through a waste heat recovery device, produces high-temperature steam that can be used for methane reforming during the biomass ammonia synthesis process, thereby improving the system's material utilization rate.

Claims

1. An IGCC system coupled with zero-emission high-purity CO2 capture from biomass, 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-fired 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 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-fired 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 equipped with a pulverized coal input pipeline, and the crude coal gas outlet of the gasifier (2) is connected to the crude 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 crude coal gas outlet of the sensible heat recovery device (3) is connected to the crude 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-fired power generation unit (5). The high-temperature mixed gas outlet of the gas-fired power generation unit (5) is connected to the high-temperature mixed gas inlet of the waste heat recovery unit (6). The waste heat recovery unit (6) produces a secondary... Carbon monoxide 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. 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 feedwater outlet of the steam power generation unit (7) is connected to the feedwater 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).

2. The IGCC system coupled with zero-emission high-purity CO2 capture from biomass as described in claim 1, characterized in that... The electrical energy generated by the gas-fired power generation unit (5) is fed into the power grid.

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

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

5. The working method of the IGCC system coupled with zero-emission high-purity CO2 capture from biomass as described in claim 1, characterized in that... It is done in the following steps: The oxygen produced by the air separation unit (1) is output in two ways: one goes into the gasifier (2) and the other goes into the gasification power generation unit (5); the nitrogen produced by the air separation unit (1) goes into 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 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. 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). The crude 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 fed into the steam power generation unit (7) to generate electricity. The crude 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). The high-temperature exhaust gas CO2 and high-temperature steam mixture generated by the gas-fired power generation unit (5) enters the waste heat recovery unit (6), and the electrical energy generated by the gas-fired power generation unit (5) is connected to the power grid. CH4 produced by the biomass fermentation unit (8) enters the methane reforming unit (9). The mixture of H2 and CO produced by the methane reforming unit (9) enters the adsorption separation unit (10). CO produced by the adsorption separation unit (10) enters the gas power generation unit for combustion. H2 produced by the adsorption separation unit (10) enters the ammonia synthesis tower (11). NH3 produced by the ammonia synthesis tower (11) is stored and recovered.

6. The working method of an IGCC system coupled with zero-emission high-purity CO2 capture from biomass according to claim 5, characterized in that... The crude gas output by the sensible heat recovery device (3) consists of 55% CO, 25% H2, 7% CO2, and 13% impurities.

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

8. The working method of an IGCC system coupled with zero-emission high-purity CO2 capture from biomass according to claim 5, 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 working method of an IGCC system coupled with zero-emission high-purity CO2 capture from biomass according to claim 5, characterized in that... Based on the adsorption separation unit (10) providing 20% ​​CO, the CO2 purity output by the waste heat recovery unit (6) can reach 99.56%.

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