A Compressed Air Deep Refrigeration Energy Storage and Oxygen-Enriched Combustion Carbon Capture System for Thermal Power Plants

Abstract

The present invention discloses a deep cryogenic energy storage and oxy-fuel combustion carbon capture system for compressed air in a thermal power plant, which includes a low-pressure compressor, a high-pressure compressor, a solid particle heat storage system and a molten rock heat storage system. The low-pressure compressor and the high-pressure compressor are driven by an electric motor or a steam turbine. When the power consumption load of the power grid is small or the power plant has surplus electricity, the surplus electric energy drives the low-pressure compressor and the high-pressure compressor to compress the air inhaled from the atmosphere. Compression causes the air temperature to rise, and the heat generated during the compression process is stored through the molten rock heat storage system and the solid particle heat storage system. The present invention solves the problems of low efficiency of existing compressed air energy storage and large loss of exhaust residual energy, effectively utilizes the internal energy of the exhaust gas, increases the concentration of carbon dioxide in the exhaust gas, and effectively reduces the operating cost of carbon capture.

Description

Technical Field

[0001] The present invention relates to the field of thermal power generation, and more specifically, to a cryogenic energy storage of compressed air and oxy-fuel combustion carbon capture system for a thermal power plant. Background Art

[0002] New energy power represented by wind power and solar energy has the characteristics of instability and volatility. When large-scale grid connection occurs, it will cause a certain impact on the power grid, and higher requirements are put forward for peak shaving, valley filling, and safe and stable regulation of the power grid. In the current power structure of our country, thermal power still occupies a large proportion. Against the background of the rapid development of new energy power in the next decade, further exploring the flexibility of thermal power plants and performing flexible peak shaving through energy storage and other means can make up for the deficiencies of new energy power and balance power supply fluctuations. From the perspective of the power consumption side, the power consumption load will also peak and valley within a day, forming a mismatch with the power generation side. Developing combined thermal energy storage peak shaving can also obtain high electricity price benefits. The method of developing thermal power plus energy storage is not only beneficial to power grid dispatching, but also can improve the income of power generation enterprises, so it has great development potential.

[0003] Among the national carbon dioxide emissions, energy production and conversion account for 47%, and thermal power generation is the main source of carbon emissions from energy conversion. Developing CCUS in thermal power plants is one of the ways to reduce carbon emissions. However, the operating cost of carbon capture has a high correlation with the concentration of carbon dioxide in flue gas. Increasing the concentration of carbon dioxide can reduce the carbon capture cost. Oxy-fuel combustion can effectively increase the concentration of carbon dioxide in flue gas and reduce the carbon capture cost. Separating oxygen and nitrogen after cryogenic cooling of compressed air can simultaneously achieve the functions of energy storage and oxy-fuel combustion.

[0004] Currently, the more widely used energy storage methods mainly include: electrochemical energy storage, pumped-storage energy storage, compressed air energy storage, etc. Electrochemical energy storage has high efficiency, fast start-up speed, and short construction period, but it has high price, small capacity, poor consistency after battery grouping, short cycle life, and large battery manufacturing pollution. Currently, it is in the early stage of development. Pumped-storage energy storage is the earliest large-scale developed energy storage method, with mature technology and low cost, suitable for large-scale energy storage, but it is greatly restricted by geographical conditions. Compressed air energy storage has low cost, long life, and is easy to achieve large-scale application.

[0005] The existing compressed air energy storage power generation technology mainly stores compressed air, and the heat released by compression is used to heat heat-conducting oil or water to heat the compressed air for expansion work. The exhaust air energy loss of this system is very large, and the compressor efficiency and turbine efficiency affect each other, resulting in low efficiency of the overall energy storage power generation system. The existing liquid air energy storage technology fails to effectively utilize the exhaust energy and is also difficult to achieve the high efficiency of the whole plant. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of the prior art and provide a compressed air cryogenic energy storage and oxy-fuel combustion carbon capture system for thermal power plants, so as to solve the problems of low efficiency of existing compressed air energy storage and large exhaust energy loss. By cryogenically separating nitrogen and oxygen from compressed air, the compression process and the expansion work process are decoupled. That is, the liquid gas can be vaporized and absorb the compressed heat storage to enter the turbine for power generation. The produced liquid oxygen and liquid nitrogen can also be used as industrial products. The turbine exhaust gas is mixed with the boiler flue gas and enters the boiler in this cycle, effectively utilizing the exhaust internal energy while increasing the carbon dioxide concentration in the exhaust gas and effectively reducing the operating cost of carbon capture.

[0007] The object of the present invention is achieved through the following solutions:

[0008] A compressed air cryogenic energy storage and oxy-fuel combustion carbon capture system for a thermal power plant includes a low-pressure compressor, a high-pressure compressor, a solid particle heat storage system, and a molten rock heat storage system. The low-pressure compressor and the high-pressure compressor are driven by an electric motor or a steam turbine driven by the motor. When the power grid load is small or the power plant has surplus electricity, the surplus electric energy drives the low-pressure compressor and the high-pressure compressor to compress the air inhaled from the atmosphere. The compression causes the air temperature to rise, and the heat generated during the compression process is stored through the molten rock heat storage system and the solid particle heat storage system.

[0009] Furthermore, the solid particle heat storage system includes a first-stage solid particle heat absorption heat exchanger, an expansion-section solid particle heat release heat exchanger, a solid particle heat storage tank, and a second-stage solid particle heat absorption heat exchanger. The solid heat storage particles are transported from the solid particle heat storage tank to the first-stage solid particle heat absorption heat exchanger by compressed air for heat absorption, and then return to the solid particle heat storage tank. The solid heat storage particles are transported from the solid particle heat storage tank to the first-stage solid particle heat absorption heat exchanger by compressed air for heat absorption, and then return to the solid particle heat storage tank. The air is compressed by the low-pressure compressor to above 450 °C and cooled to about 220 °C after passing through the first-stage solid particle heat absorption heat exchanger.

[0010] Furthermore, the air coming out of the first-stage solid particle heat absorption heat exchanger enters the high-pressure compressor for compression. After compression, the temperature rises to above 650 °C and is stored through the molten rock heat storage system.

[0011] Furthermore, the lava heat storage system includes a compression section lava heat absorption heat exchanger, a high-temperature lava storage tank, a compression section lava pump, an expansion section lava pump and an expansion section lava heat release heat exchanger; the high-temperature lava in the high-temperature lava storage tank is transported by the compression section lava pump into the compression section lava heat absorption heat exchanger to absorb heat, and the lava after heat absorption flows back to the high-temperature lava storage tank; the high-pressure mixed gas preliminarily heated by the expansion section solid particle heat release heat exchanger enters the expansion section lava heat release heat exchanger and is further heated by the high-temperature lava extracted from the high-temperature lava storage tank by the expansion section lava pump, the heated high-temperature and high-pressure gas enters the gas power generation turbine to generate electricity, and the lava after heat exchange flows back into the high-temperature lava storage tank under the residual pressure of the expansion section lava pump; the high-temperature air at the outlet of the high-pressure compressor enters the compression section lava heat absorption heat exchanger to cool down to about 560°C, and then enters the second-stage solid particle heat absorption heat exchanger to heat the solid particles.

[0012] Furthermore, the solid heat storage particles are transported from the solid particle heat storage tank by compressed air to the second-stage solid particle heat absorption heat exchanger and the compression section lava heat absorption heat exchanger outlet air for heat exchange, and the high-pressure air temperature is cooled to about 320°C. The solid particles after heat exchange are returned to the solid particle heat storage tank.

[0013] Furthermore, the high-pressure air enters the expander after passing through the particle heat exchanger. The high-pressure air expands and does work to drive the engine to generate electricity and be connected to the power grid. The temperature of the compressed air is reduced to about 80°C. After passing through the cooler 15, the temperature is reduced to about 20°C.

[0014] Furthermore, the air at the cooler outlet enters the distillation tower for fractionation, and the liquid oxygen enters the liquid oxygen storage tank; most of the fractionated liquid nitrogen is bottled and sold as a by-product, and the liquid oxygen can be bottled and sold according to actual conditions or used for power generation through the back-end system.

[0015] Furthermore, during peak hours of electricity consumption or when the power grid needs to shave peak loads, liquid oxygen is pumped to a liquid oxygen vaporizer for gasification through a liquid oxygen pump, and enters a high-pressure gas buffer tank after the gasification pressure reaches about 4.6 MPa; liquid nitrogen is pumped to a liquid nitrogen vaporizer for gasification through a liquid nitrogen pump, and enters a high-pressure gas buffer tank 22 for gasification after the gasification pressure reaches about 4.6 MPa, and is mixed with high-pressure oxygen. The oxygen mixing ratio can be adjusted to 30-80% according to the peak shaving demand.

[0016] Furthermore, the mixed high-pressure mixed gas enters the solid particle exothermic heat exchanger of the expansion section to absorb heat, and the high-pressure mixed gas is heated to about 260°C, and then enters the lava heat exchange system for heating, and the temperature rises to about 550°C after passing through the lava exothermic heat exchanger of the expansion section.

[0017] Furthermore, the high-pressure and high-temperature mixed gas heated by lava enters the gas power generation turbine to expand and do work, driving the generator to generate electricity and integrating into the power grid. The magnitude of the peak shaving power generation is adjusted by the demand on the power grid side, and by controlling the gasification amounts of liquid oxygen and liquid nitrogen, the amount of high-pressure air entering the gas power generation turbine to do work is regulated.

[0018] Furthermore, the exhaust gas at the outlet of the gas power generation turbine has a certain internal energy, and direct emission results in relatively large losses. This part of the oxygen-rich gas and the boiler flue gas enter the flue gas oxygen-rich mixer for mixing, and a certain proportion of high-temperature oxygen-rich gas is configured to enter the boiler for combustion. After flue gas recirculation, the carbon dioxide concentration in the boiler exhaust gas increases, and the carbon dioxide is recovered by the CCUS system for utilization or landfill. By adjusting the oxygen proportion entering the high-pressure gas buffer tank and the gas volume entering the flue gas oxygen-rich mixer at the CCUS outlet, the oxygen-rich proportion of the gas entering the boiler can be controlled.

[0019] Advantages of the present invention:

[0020] The compressed air cryogenic energy storage system for thermal power plants of the present invention decouples the compression process and the expansion process of the gas. Through two-stage compression and inter-stage cooling, the compressor can reach the maximum efficiency. By heating the expanding and working gas through the heat storage system, the efficiency of the gas power generation turbine is improved, thereby enhancing the overall system efficiency.

[0021] The compressed air cryogenic energy storage system for thermal power plants of the present invention designs a lava heat exchange system and a solid particle heat storage system. These two heat storage methods have the characteristics of large heat storage capacity and high medium temperature, which can significantly increase the gas temperature before entering the gas power generation turbine. Moreover, through the liquid oxygen pump and the liquid nitrogen pump, the pressure of the gas after gasification can be significantly increased, raising the total temperature and total pressure of the gas at the inlet of the power generation turbine, thereby effectively improving the efficiency of the gas power generation turbine.

[0022] The compressed air cryogenic energy storage system for thermal power plants of the present invention is provided with a cryogenic unit, which can achieve product diversification. The liquid oxygen and liquid nitrogen after rectification can be sold as by-products or flexibly connected to the system for power generation according to the peak shaving situation; when a large amount of electricity is required during the peak shaving process, the liquid oxygen and liquid nitrogen can quickly enter the turbine to do work and generate electricity through the processes of rapid gasification and reheating. The system has a fast response speed and high adjustment flexibility.

[0023] The compressed air cryogenic energy storage system for thermal power plants of the present invention is provided with a cryogenic unit. The storage amounts of the liquid oxygen and liquid nitrogen after rectification are large, and the heat storage amounts of the lava heat storage and the solid heat storage are also larger than those of the conventional heat storage methods. The heat storage medium temperature is high, which is easy to increase the temperature and pressure of the gas used for power generation in large quantities, facilitating the large-scale realization of the entire energy storage system.

[0024] The deep cryogenic energy storage of compressed air and oxy-fuel combustion carbon capture system of the present invention can effectively utilize the exhaust heat of the power generation turbine; the oxygen-rich exhaust gas is mixed with the flue gas and then enters the boiler to achieve oxy-fuel combustion, and the oxygen-rich ratio can be flexibly adjusted by the mixing ratio of liquid oxygen and liquid nitrogen, with a wide adjustment range; the oxy-fuel combustion coupled with flue gas recirculation can reduce the operating cost of CCUS. Brief Description of the Drawings

[0025] The drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic structural diagram of the present invention;

[0027] In the figure, 1 - low-pressure compressor, 2 - high-pressure compressor, 3 - first-stage solid particle heat absorption heat exchanger, 4 - compressed section molten lava heat absorption heat exchanger, 5 - molten lava storage tank, 6 - compressed section molten lava pump, 7 - expansion section molten lava pump, 8 - expansion section molten lava heat release heat exchanger, 9 - expansion section solid particle heat release heat exchanger, 10 - solid particle heat storage tank, 11 - second-stage solid particle heat absorption heat exchanger, 12 - expander, 13 - gas power generation turbine, 14 - rectification tower, 15 - cooler, 16 - liquid oxygen storage tank, 17 - liquid oxygen pump, 18 - liquid oxygen vaporizer, 19 - flue gas oxygen-rich mixer, 20 - liquid nitrogen pump, 21 - liquid nitrogen vaporizer, 22 - high-pressure gas buffer tank. Detailed Embodiments

[0028] All the features disclosed in all the embodiments in this specification, or all the steps in the methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined or replaced in any way.

[0029] The detailed structure, application principle, function and efficacy of the present invention, such as Figure 1 , are described in detail through the following embodiments:

[0030] A deep cryogenic energy storage of compressed air and oxy-fuel combustion carbon capture system of the present invention includes a low-pressure compressor 1, a high-pressure compressor 2, a first-stage solid particle heat absorption heat exchanger 3, a compressed section molten lava heat absorption heat exchanger 4, a high-temperature molten lava storage tank 5, a compressed section molten lava pump 6, an expansion section molten lava pump 7, an expansion section molten lava heat release heat exchanger 8, an expansion section solid particle heat release heat exchanger 9, a solid particle heat storage tank 10, a second-stage solid particle heat absorption heat exchanger 11, an expander 12, a gas power generation turbine 13, a rectification tower 14, a cooler 15, a liquid oxygen storage tank 16, a liquid oxygen pump 17, a liquid oxygen vaporizer 18, a flue gas oxygen-rich mixer 19, a liquid nitrogen pump 20, a liquid nitrogen vaporizer 21 and a high-pressure gas buffer tank 22.

[0031] Working principle of the present invention: The compressor is driven by the valley computer of the power plant or surplus electric energy to compress air for storing electric energy. During the compression process, the efficiency of the compressor is improved through intercooling heat exchange. After compression, the air drives the generator to generate electricity through the turbine expander, and the temperature of the air exhausted from the turbine expander decreases. Then it enters the rectification tower to realize air liquefaction. When the power grid needs electricity, the stored liquid oxygen and liquid nitrogen are released and heated by the molten rock heat storage and solid particle heat storage systems at the front end of the system to obtain high-temperature and high-pressure compressed gas, which enters the turbine for power generation. The system increases the total temperature and total pressure of the gas entering the power generation turbine, thus improving the power generation efficiency. The exhaust of the turbine has a certain amount of heat energy, and the oxygen content can be adjusted by the ratio of liquid oxygen to liquid nitrogen. After mixing with the boiler flue gas, it enters the boiler to realize oxygen-enriched combustion. By increasing the proportion of oxygen entering the boiler, the carbon dioxide concentration in the flue gas can be increased, and the CCUS operation cost can be reduced.

[0032] The following further illustrates the present invention through specific embodiments.

[0033] Embodiment 1: A compressed air cryogenic energy storage and oxygen-enriched combustion carbon capture system for a thermal power plant, including a low-pressure compressor, a high-pressure compressor, a solid particle heat storage system, and a molten rock heat storage system. The low-pressure compressor and the high-pressure compressor are driven by an electric motor or driven by a steam turbine. When the power consumption load of the power grid is small or the power plant has surplus electricity, the surplus electric energy drives the low-pressure compressor and the high-pressure compressor to compress the air inhaled from the atmosphere. Compression increases the air temperature, and the heat generated during the compression process is stored through the molten rock heat storage system and the solid particle heat storage system.

[0034] Embodiment 2: On the basis of Embodiment 1, as Figure 1 , it is a schematic diagram of a compressed air cryogenic energy storage and oxygen-enriched combustion carbon capture system for a thermal power plant of the present invention. When the power consumption load of the power grid is small or the power plant has surplus electricity, the surplus electric energy drives the low-pressure compressor 1 and the high-pressure compressor 2 to inhale and compress the air from the atmosphere. During the compression process, the air temperature gradually increases. A heat exchanger is arranged between the two-stage compressors to absorb the heat generated during the compression process, aiming to improve the compression process efficiency and reduce heat loss. The air is compressed by the low-pressure compressor 1 to 2.0 MPa and above 450 °C, and then enters the solid particle heat storage system for heat exchange. After cooling to about 220 °C through the first-stage solid particle heat absorption heat exchanger 3, it then enters the high-pressure compressor 2 for further compression. After compression, the temperature rises to above 650 °C and the pressure is 4.6 MPa. The gas at the outlet of the high-pressure compressor enters the compression section molten rock heat absorption heat exchanger 4 to cool to about 560 °C, and then enters the second-stage solid particle heat absorption heat exchanger 11 to heat the solid particles. The high-pressure air temperature drops to about 320 °C.

[0035] The high-pressure air enters the expander 12 after passing through the particle heat exchanger. The high-pressure air expands to do work, driving the engine to generate electricity and feed it into the power grid. The temperature of the compressed air drops to about 80 °C. After passing through the cooler 15, the temperature drops to about 20 °C.

[0036] The air at the outlet of the cooler 15 enters the distillation column 14 for fractionation. The liquid oxygen enters the liquid oxygen storage tank 16. Most of the fractionated liquid nitrogen is mainly bottled and sold as a by-product. The liquid oxygen can be bottled and sold according to the actual situation or used for power generation through the backend system.

[0037] During the peak electricity consumption period or when the power grid needs to adjust the peak load, the liquid oxygen is transported to the liquid oxygen vaporizer 18 by the liquid oxygen pump 17 for vaporization. After the vaporization pressure reaches about 4.6 MPa, it enters the high-pressure gas buffer tank 22. The liquid nitrogen is transported to the liquid nitrogen vaporizer 21 by the liquid nitrogen pump 20 for vaporization. After the vaporization pressure reaches about 4.6 MPa, it enters the high-pressure gas buffer tank 22 and mixes with the high-pressure oxygen. According to the peak load adjustment demand, the oxygen mixing ratio can be adjusted to 30-80%.

[0038] The mixed high-pressure gas mixture enters the expansion section solid particle heat exchanger 9 to absorb heat. The high-pressure gas mixture is heated to about 260 °C, and then enters the molten rock heat exchange system for heating. After passing through the expansion section molten rock heat exchanger 8, the temperature rises to about 550 °C.

[0039] The high-pressure and high-temperature mixed gas heated by the molten rock enters the gas power generation turbine 13 to expand and do work, driving the generator to generate electricity and feed it into the power grid. The amount of peak load adjustment power generation is adjusted by the demand on the power grid side, and by controlling the amount of high-pressure air entering the gas power generation turbine 13 to do work through the vaporization amounts of liquid oxygen and liquid nitrogen.

[0040] The exhaust gas at the outlet of the gas power generation turbine 13 has a certain internal energy, and direct emission causes relatively large losses. This part of the oxygen-rich gas and the boiler flue gas enter the flue gas oxygen-rich mixer 19 for mixing, and a certain proportion of high-temperature oxygen-rich gas is configured to enter the boiler for combustion. After flue gas recirculation, the carbon dioxide concentration in the boiler exhaust gas increases. The carbon dioxide is recovered through the CCUS system for utilization or landfill. By adjusting the oxygen ratio entering the high-pressure gas buffer tank 22 and the gas volume entering the flue gas oxygen-rich mixer 19 at the CCUS outlet, the oxygen-rich ratio of the gas entering the boiler can be controlled. Oxygen-rich combustion can increase the carbon dioxide ratio in the flue gas and reduce the operating cost of CCUS.

[0041] Except for the above examples, those skilled in the art can obtain inspiration according to the above disclosure or make modifications by using the knowledge or technology in related fields to obtain other embodiments. The features of each embodiment can be interchanged or replaced. As long as the modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, they should all be within the protection scope of the appended claims of the present invention.

Claims

1. A cryogenic energy storage of compressed air and oxy-fuel combustion carbon capture system for thermal power plants, characterized in that It includes a low-pressure compressor (1), a high-pressure compressor (2), a solid particle heat storage system and a molten lava heat storage system. The low-pressure compressor (1) and the high-pressure compressor (2) are driven by an electric motor or a steam turbine. When the electricity load of the power grid is small or the power plant has surplus electricity, the surplus electric energy drives the low-pressure compressor (1) and the high-pressure compressor (2) to compress the air inhaled from the atmosphere. The temperature of the compressed air rises, and the heat of the compression process is stored through the molten lava heat storage system and the solid particle heat storage system. The molten lava heat storage system includes: a compression-section molten lava heat absorption heat exchanger (4), a high-temperature molten lava storage tank (5), a compression-section molten lava pump (6), an expansion-section molten lava pump (7), and an expansion-section molten lava heat release heat exchanger (8). The high-temperature air at the outlet of the high-pressure compressor (2) enters the compression-section molten lava heat absorption heat exchanger (4) to be cooled and then enters the solid particle heat storage system. The high-temperature molten lava in the high-temperature molten lava storage tank (5) is transported by the compression-section molten lava pump (6) into the compression-section molten lava heat absorption heat exchanger (4) to absorb heat, and the molten lava after heat absorption flows back to the high-temperature molten lava storage tank (5). The high-pressure mixed gas preliminarily heated by the expansion-section solid particle heat release heat exchanger (9) enters the expansion-section molten lava heat release heat exchanger (8) and is further heated by the high-temperature molten lava pumped out of the high-temperature molten lava storage tank (5) by the expansion-section molten lava pump (7). The heated high-temperature and high-pressure gas enters the gas power generation turbine (13) to generate electricity, and the molten lava after heat exchange flows back into the high-temperature molten lava storage tank (5) under the residual pressure of the expansion-section molten lava pump (7). The solid particle heat storage system includes a first-stage solid particle heat absorption heat exchanger (3), an expansion-section solid particle heat release heat exchanger (9), a solid particle heat storage tank (10), and a second-stage solid particle heat absorption heat exchanger (11). The high-temperature air at the outlet of the high-pressure compressor (2) enters the second-stage solid particle heat absorption heat exchanger (11) of the solid particle heat storage system to heat the solid particles after being cooled in the compression-section molten lava heat absorption heat exchanger (4). The solid heat storage particles are transported from the solid particle heat storage tank (10) by compressed air to the first-stage solid particle heat absorption heat exchanger (3) to absorb heat and then return to the solid particle heat storage tank (10). The solid heat storage particles are transported from the solid particle heat storage tank (10) by compressed air to the second-stage solid particle heat absorption heat exchanger (11) to exchange heat with the air at the outlet of the compression-section molten lava heat absorption heat exchanger (4), and the solid particles after heat exchange return to the solid particle heat storage tank (10). The mixed high-pressure mixed gas enters the expansion-section solid particle heat release heat exchanger (9) to absorb heat. It includes an expander (12) and a cooler (15). The high-pressure air enters the expander 12 after passing through the second-stage solid particle heat absorption heat exchanger (11). The high-pressure air expands to do work to drive the engine to generate electricity and is incorporated into the power grid. After the temperature of the compressed air drops, it passes through the cooler (15). It includes a rectification column (14) and a liquid oxygen storage tank (16). The air at the outlet of the cooler (15) enters the rectification column (14) for fractionation, and the liquid oxygen enters the liquid oxygen storage tank (16). During peak electricity consumption periods or when the power grid needs to adjust its peak load, liquid oxygen is transported to the liquid oxygen vaporizer (18) by the liquid oxygen pump (17) for vaporization. After vaporization, it enters the high-pressure gas buffer tank (22); liquid nitrogen is transported to the liquid nitrogen vaporizer (21) by the liquid nitrogen pump (20) for vaporization. After vaporization, it enters the high-pressure gas buffer tank (22) and mixes with high-pressure oxygen. According to the peak load adjustment requirements, the oxygen mixing ratio is adjusted to 30% - 80%. It includes a gas power generation turbine (13). The high-pressure and high-temperature mixed gas heated by lava enters the gas power generation turbine (13) for expansion work, driving the generator to generate electricity and connecting to the power grid. Part of the oxygen-rich gas at the outlet of the gas power generation turbine (13) and the boiler flue gas enter the flue gas oxygen-rich mixer (19) for mixing, which can adjust the oxygen ratio entering the high-pressure gas buffer tank (22) and the gas volume entering the flue gas oxygen-rich mixer (19) from the CCUS outlet.

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