A system and a method for regulating combustion of coal powder mixed with hydrogen in a coal-fired furnace

Abstract

This invention discloses a system and control method based on the combustion of pulverized coal with hydrogen in a coal-fired boiler. The system consists of a fuel preparation section, a furnace combustion section, and a tail gas treatment section. The fuel preparation section includes a liquid hydrogen passage, a gas-liquid heat exchanger, an air passage, and a coal mill. The furnace combustion section includes a gas-solid burner nozzle, a pulverized coal burner nozzle, a burnout air nozzle, a hydrogen-coal co-combustion zone, a pulverized coal main combustion zone, a burnout zone, a heat exchanger, and a steam turbine. The tail gas treatment section includes purification equipment, a carbon dioxide collection device, a chimney, a regulating valve, and a carbon dioxide storage device. The control method of this invention improves upon the sources of heat loss in coal-fired power plants and addresses the clean and pollution-free characteristics of hydrogen combustion. Simultaneously, by blending hydrogen, it achieves the conservation and complete combustion of fossil fuels. This method is environmentally friendly, efficient, and fully utilizes energy, meeting peak-shaving requirements while also enhancing the utilization of greenhouse gases to a certain extent, thus achieving a low-carbon goal.

Description

Technical Field

[0001] This invention relates to a method for clean combustion by blending and its combustion and control under varying operating loads. Specifically, it relates to a system and control method for combustion of pulverized coal mixed with hydrogen in a coal-fired boiler. Background Technology

[0002] To build an ecological civilization system, my country is striving to construct a clean, low-carbon, safe, and efficient energy system. However, it cannot be ignored that coal still accounts for a large share of power generation and related industries. Therefore, research on the combustion and control of coal-fired power plants remains of great significance. Developing a method that uses traditional fossil fuels while blending them with clean energy is of practical significance in order to reduce dependence on and consumption of coal during combustion and to achieve operation under high and variable conditions. This can also achieve low-carbon goals to a certain extent and meet the current overall demand for grid-connected peak shaving of thermal power plants.

[0003] Stable combustion remains a problem to be solved under the changing operating conditions of boilers in order to adapt to peak-shaving demands. Therefore, meeting the flexible peak-shaving requirements of the unit has become the core and key issue that urgently needs to be addressed. Summary of the Invention

[0004] Considering the non-renewable nature and significant pollution of pulverized coal combustion, as well as the difficulties in stabilizing and regulating combustion with hydrogen blending, the purpose of this invention is to provide a system and control method based on the combustion of pulverized coal with hydrogen blending in a coal-fired boiler. This system and method are environmentally friendly, efficient, and make full use of energy. They can control the co-combustion of hydrogen and pulverized coal to achieve stable combustion, meeting peak-shaving requirements while also enhancing the utilization of greenhouse gases to a certain extent, thus achieving a low-carbon goal.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace, the system comprising a fuel preparation section, a furnace combustion section and an exhaust gas treatment section;

[0007] The fuel preparation section includes a liquid hydrogen passage 1, a gas-liquid heat exchanger 2, an air passage 3, and a coal mill 4; the liquid hydrogen passage 1 is connected to the tube-side inlet of the gas-liquid heat exchanger 2, the tube-side outlet of the gas-liquid heat exchanger 2 is connected to the mixed fuel inlet of the coal mill 4, and the air passage 3 is connected to the air inlet of the coal mill 4.

[0008] The furnace combustion section includes multiple alternating hydrogen-coal co-combustion zones and pulverized coal main combustion zones. The upper and lower parts of the furnace combustion section are hydrogen-coal co-combustion zones, forming a structure of hydrogen-coal co-combustion zone-pulverized coal main combustion zone-hydrogen-coal co-combustion zone. Above the upper hydrogen-coal co-combustion zone is the burnout zone 10. The hydrogen-coal co-combustion zone, pulverized coal main combustion zone, and burnout zone 10 are respectively provided with gas-solid burner nozzles, pulverized coal burner nozzles, and burnout air nozzles 7. It also includes a heat exchanger 11 and a steam turbine 12. The heat exchanger 11 is located at the tail of the furnace. The high-temperature steam outlet of the heat exchanger 11 is connected to the inlet of the steam turbine 12. The steam outlet of the steam turbine 12 is connected to the shell-side inlet of the gas-liquid heat exchanger 2.

[0009] The exhaust gas treatment section includes a purification device 13, a carbon dioxide collection device 14, and a chimney 15, which are sequentially connected to the flue gas outlet of the heat exchanger 11. The carbon dioxide outlet of the carbon dioxide collection device 14 is divided into two paths by a first regulating valve 16. One path is connected to the carbon dioxide storage device 17, and the other path is divided into two paths by a second regulating valve 18. One path is connected to the tube side outlet of the gas-liquid heat exchanger 2, and the other path is further divided into two paths by a third regulating valve 19. One path is connected to the shell side of the gas-liquid heat exchanger 2, and the other path is connected to the liquid hydrogen passage 1.

[0010] The coal mill 4 is equipped with an air inlet 4-1, an adjusting plate 4-2, a coarse powder outlet 4-3, a mixed fuel inlet 4-4, and a mixed fuel outlet 4-5. Air enters through the air inlet 4-1 and drives the coal powder to flow. The coarse and fine powders are separated at the adjusting plate 4-2, causing the fine coal powder to fall below and the coarse coal powder to flow out from the coarse powder outlet 4-3. A mixture of hydrogen and carbon dioxide gas drives the fine coal powder to circulate around the coal drop pipe and be blown out from the mixed fuel outlet 4-5 through the mixed fuel inlet 4-4.

[0011] The combustion section of the furnace is also equipped with several secondary air nozzles and igniters, arranged in a tangential pattern on each wall of the furnace.

[0012] When carbon dioxide and hydrogen are mixed in the gas-liquid heat exchanger 2, the deflagration pressure and combustion intensity of hydrogen are effectively suppressed, and when mixed with pulverized coal, the purpose of low carbon emissions can be achieved.

[0013] The structure of the gas-liquid heat exchanger 2 connected to the liquid hydrogen passage 1 is designed to utilize the heat from the cold source at the tail end of the steam turbine, thereby improving the overall thermal efficiency and reducing the need for geographical restrictions on coal-fired units.

[0014] The coal mill 4 separates coal powder of different fineness into two streams. Air drives the coarse coal powder, while a mixed airflow of hydrogen and carbon dioxide drives the fine coal powder. The fully combusted hydrogen and fine coal powder airflow drive the coarse coal powder airflow to burn, further achieving the goal of saving metal consumables in the coal mill.

[0015] The exhaust gas treatment section is equipped with a carbon dioxide collection device 14 and a carbon dioxide storage device 17, which provide the carbon dioxide required in the pipeline during the initial start-up process, provide the carbon dioxide flow required to regulate the hydrogen flow, and provide the initial heat for liquid hydrogen heat exchange in the gas-liquid heat exchanger 2.

[0016] The exhaust gas treatment section utilizes the heat-insulating properties of carbon dioxide to encapsulate the carbon dioxide in the liquid hydrogen pipeline 1, thereby providing a good temperature space for the liquid hydrogen, making its heat exchange more stable, achieving the purpose of utilizing carbon dioxide and meeting the low-carbon requirements.

[0017] The aforementioned method for controlling a system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired boiler includes the following steps:

[0018] Step 1, fuel introduction: Liquid hydrogen fuel is supplied by liquid hydrogen passage 1 into gas-liquid heat exchanger 2, where the steam after work is provided with heat to turn the liquid hydrogen into gas; the gaseous hydrogen is mixed with carbon dioxide provided by carbon dioxide storage device 17 and then introduced into coal mill 4.

[0019] Cold air is supplied by air passage 3 and enters coal mill 4 through air inlet 4-1, driving the coal powder to flow. The coarse and fine powders are separated by regulating plate 4-2. The coarse coal powder is discharged through coarse powder outlet 4-3, while the fine coal powder falls down. A mixed gas flow of hydrogen and carbon dioxide is sent into coal mill 4 through mixed fuel inlet 4-4, driving the fine coal powder that meets the conditions to enter the pipeline from mixed fuel outlet 4-5.

[0020] The mixed fuel of hydrogen and fine coal powder is fed into the furnace through the gas-solid burner nozzle, and the mixed fuel of air and coarse coal powder is fed into the furnace through the pulverized coal burner nozzle.

[0021] Step 2, Combustion in the furnace area: The furnace is divided into a hydrogen-coal co-combustion zone, a pulverized coal main combustion zone, and a burnout zone 10. The mixed fuel of hydrogen and fine pulverized coal is fed into the furnace through the gas-solid burner nozzle and burned in the hydrogen-coal co-combustion zone. The mixed fuel of air and coarse pulverized coal is fed into the furnace through the pulverized coal burner nozzle and burned in the pulverized coal main combustion zone. The remaining fuel is fully burned in the burnout zone 10. After the high-temperature flue gas is heat-exchanged by the heat exchanger 11, the high-temperature steam flows into the steam turbine 12 to do work. The steam after doing work enters the gas-liquid heat exchanger 2 for heat exchange.

[0022] Step 3, storage and utilization of carbon dioxide: After heat exchange, the flue gas passes through the purification equipment 13 for dust removal, desulfurization and denitrification to meet the standards; the purified flue gas flows through the carbon dioxide collection device 14, causing the carbon dioxide in the flue gas to be diverted and then pass through the first regulating valve 16, while the remaining gas is discharged through the chimney 15; the carbon dioxide passing through the first regulating valve 16 is divided into two paths, one of which enters the carbon dioxide storage device 17 to reach its maximum capacity, and the other path leads to the second regulating valve 18, which controls the carbon dioxide diversion. One path enters the liquid hydrogen passage 1 for heat preservation, and the other path enters the gaseous hydrogen pipeline.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] This invention employs the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace, fully utilizing the characteristics of hydrogen—high calorific value, vigorous combustion, and clean, pollution-free combustion. This system and method can achieve the goal of co-combustion of pulverized coal and hydrogen, and can also utilize carbon dioxide to a certain extent, thus generally meeting the requirements of cleanliness, high efficiency, energy saving, and environmental protection. Attached Figure Description

[0025] Figure 1 This is a diagram of a system for blending hydrogen with pulverized coal in a coal-fired boiler.

[0026] Figure 2 This is a simplified structural diagram of a coal mill. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, this embodiment is a system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace. The system consists of a fuel preparation section, a furnace combustion section, and a tail gas treatment section. The fuel preparation section includes a liquid hydrogen passage 1, a gas-liquid heat exchanger 2, an air passage 3, and a coal mill 4. The liquid hydrogen passage (1) is connected to the tube-side inlet of the gas-liquid heat exchanger (2), the tube-side outlet of the gas-liquid heat exchanger (2) is connected to the mixed fuel inlet of the coal mill (4), and the air passage (3) is connected to the air inlet of the coal mill (4).

[0029] The furnace combustion section includes, from bottom to top, a lower hydrogen-coal co-combustion zone 8-1, a lower pulverized coal main combustion zone 9-1, a middle hydrogen-coal co-combustion zone 8-2, an upper pulverized coal main combustion zone 9-2, an upper hydrogen-coal co-combustion zone 8-3, and a burnout zone 10. The lower hydrogen-coal co-combustion zone 8-1, the lower pulverized coal main combustion zone 9-1, the middle hydrogen-coal co-combustion zone 8-2, the upper pulverized coal main combustion zone 9-2, the upper hydrogen-coal co-combustion zone 8-3, and the burnout zone 10 are respectively equipped with a lower gas-solid burner nozzle 5-1, a lower pulverized coal burner nozzle 6-1, a middle gas-solid burner nozzle 5-2, an upper pulverized coal burner nozzle 6-2, an upper gas-solid burner nozzle 5-3, and a burnout air nozzle 7. It also includes a heat exchanger (11) and a steam turbine (12). The heat exchanger (11) is located at the tail end of the furnace. The high-temperature steam outlet of the heat exchanger (11) is connected to the inlet of the steam turbine (12), and the steam outlet of the steam turbine (12) is connected to the shell-side inlet of the gas-liquid heat exchanger (2). In addition to the nozzles, the furnace wall also has several secondary air nozzles, igniters, etc., arranged in a tangential pattern on each wall of the furnace.

[0030] The exhaust gas treatment section includes a purification device (13), a carbon dioxide collection device (14), and a chimney (15) that are sequentially connected to the flue gas outlet of the heat exchanger (11). The carbon dioxide outlet of the carbon dioxide collection device (14) is divided into two paths through a first regulating valve (16). One path is connected to the carbon dioxide storage device (17), and the other path is divided into two paths through a second regulating valve (18). One path is connected to the tube side outlet of the gas-liquid heat exchanger (2), and the other path is divided into two paths again through a third regulating valve (19). One path is connected to the shell side of the gas-liquid heat exchanger (2), and the other path is connected to the liquid hydrogen passage (1).

[0031] like Figure 2 As shown, the coal mill 4 is equipped with an air inlet 4-1, an adjusting plate 4-2, a coarse powder outlet 4-3, a mixed fuel inlet 4-4, and a mixed fuel outlet 4-5. The adjusting plate 4-2 separates the coarse and fine coal powders. Air enters through the air inlet 4-1, driving the coal powder flow. The adjusting plate 4-2 separates the coarse and fine coal powders, causing the fine coal powder to fall below, while the coarse coal powder flows out from the coarse powder outlet 4-3. A mixture of hydrogen and carbon dioxide gas enters through the mixed fuel inlet 4-4, driving the fine coal powder to circulate around the coal chute and exit from the mixed fuel outlet 4-5.

[0032] Example 1: Initial Ignition

[0033] (1) As Figure 1As shown, the fuel supply is as follows: The first regulating valve 16 is adjusted to disconnect the carbon dioxide collection device 14 and the carbon dioxide storage device 17. The carbon dioxide storage device 17 is activated to initially supply the required carbon dioxide to the pipeline, bringing the flow rate to 350 kg / h. This carbon dioxide then flows to the second regulating valve 18, splitting the carbon dioxide flow into two paths: one path enters the hydrogen pipeline after the gas-liquid heat exchanger 2, and the other flows into the liquid hydrogen path. The third regulating valve 19 is activated to supply carbon dioxide to the gas-liquid heat exchanger 2, providing initial heat exchange. The liquid hydrogen path 1 is activated to supply 250 kg / h of liquid hydrogen fuel into the gas-liquid heat exchanger 2, where the steam after work provides heat, causing the liquid hydrogen to turn into a gaseous state. The gaseous hydrogen and carbon dioxide are then mixed and fed into the coal mill 4.

[0034] Cool air at 20 m / s is supplied by air passage 3 and enters the coal mill 4 through air inlet 4-1, causing the pulverized coal to flow. The coarse and fine pulverized coal are separated by regulating plate 4-2, with the coarse pulverized coal discharged through coarse powder outlet 4-3 and the fine pulverized coal falling down. A mixed gas flow of hydrogen and carbon dioxide is sent into the coal mill 4 through mixed fuel inlet 4-4, causing the qualified fine pulverized coal to enter the pipeline through mixed fuel outlet 4-5.

[0035] The mixed fuel of hydrogen and fine coal powder is fed into the furnace through three gas-solid burner nozzles 5-1, 5-2, and 5-3, while the mixed fuel of air and coarse coal powder is fed into the furnace through two pulverized coal burner nozzles 6-1 and 6-2.

[0036] (2) Figure 1 As shown, combustion in the furnace area: The openings of the three gas-solid burner nozzles 5-1, 5-2, and 5-3 are increased to 90%, and the mixed fuel of hydrogen and fine pulverized coal is fed into the furnace through the gas-solid burner nozzles and burned in the three hydrogen-coal co-combustion zones 8-1, 8-2, and 8-3 respectively. The openings of the two pulverized coal burner nozzles 6-1 and 6-2 are decreased to 40%, and the mixed fuel of air and coarse pulverized coal is fed into the furnace through the pulverized coal burner nozzles and burned in the two pulverized coal main combustion zones 9-1 and 9-2 respectively. The high heat generated by the combustion of hydrogen and light pulverized coal ignites the air and heavy pulverized coal flow. The remaining fuel is fully burned in the burnout zone 10. After heat exchange in the heat exchanger 11, the high-temperature flue gas flows into the steam turbine 12 to do work. The steam after doing work enters the gas-liquid heat exchanger 2 for further heat exchange.

[0037] (3) Figure 1As shown, carbon dioxide storage and utilization: After heat exchange, the flue gas undergoes dust removal, desulfurization, and denitrification in purification equipment 13 to meet standards. The purified flue gas flows through carbon dioxide collection device 14, where carbon dioxide is diverted and passes through the first regulating valve 16, while the remaining gas is discharged through chimney 15. The first regulating valve 16 is connected to the carbon dioxide storage device 17 to replenish consumed carbon dioxide, adjusting it to the normal flow path after reaching its maximum capacity. Once the boiler is operating normally and the steam from the turbine is sufficient to provide the required heat, the third regulating valve 19 is disconnected.

[0038] Example 2: Reduced load combustion

[0039] (1) As Figure 1 As shown, the fuel supply is as follows: The first regulating valve 16 is switched to the normal flow path, activating the carbon dioxide storage device 17 to provide more carbon dioxide from the pipeline, increasing its total flow rate to 300 kg / h. This carbon dioxide then flows to the second regulating valve 18, allowing a larger amount of carbon dioxide to flow into the hydrogen pipeline. The opening of the liquid hydrogen passage 1 is reduced, adjusting the supplied liquid hydrogen fuel flow rate to 180 kg / h. After the gaseous hydrogen and carbon dioxide are mixed, they are introduced into the coal mill 4. Cold air at 15 m / s is supplied by the air passage 3 and enters the coal mill 4 through the air inlet 4-1, reducing the amount of coal in the coal mill 4 to 70% of the original pulverized coal amount. The mixed fuel of hydrogen and fine pulverized coal is fed into the furnace through the three gas-solid burner nozzles 5-1, 5-2, and 5-3, while the mixed fuel of air and coarse pulverized coal is fed into the furnace through the two pulverized coal burner nozzles 6-1 and 6-2.

[0040] (2) Figure 1 As shown, combustion in the furnace area: The openings of the three gas-solid burner nozzles 5-1, 5-2, and 5-3 are reduced to 80% of their full opening. The mixed fuel of hydrogen and fine pulverized coal is fed into the furnace through the gas-solid burner nozzles and burned in the three hydrogen-coal co-combustion zones 8-1, 8-2, and 8-3 respectively. The openings of the two pulverized coal burner nozzles 6-1 and 6-2 are adjusted to 80% of their full opening, reducing the secondary air volume in the boiler. The remaining fuel is fully burned in the burnout zone 10. After heat exchange in the heat exchanger 11, the high-temperature flue gas flows into the steam turbine 12 to perform work. The steam after performing work then enters the gas-liquid heat exchanger 2 for further heat exchange.

[0041] (3) Figure 1As shown, the storage and utilization of carbon dioxide are as follows: After heat exchange, the flue gas undergoes dust removal, desulfurization, and denitrification in purification equipment 13 to meet standards. The purified flue gas flows through carbon dioxide collection device 14, where the carbon dioxide in the flue gas is diverted and passes through the first regulating valve 16, while the remaining gas is discharged through chimney 15. The first regulating valve 16 is controlled to the normal passage to introduce carbon dioxide. After combustion stabilizes and the overall operating conditions are reduced, the passage to carbon dioxide storage device 17 is connected to replenish the consumed carbon dioxide until it reaches its maximum capacity, after which it is adjusted back to the normal passage.

Claims

1. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace, characterized in that: The system includes a fuel preparation section, a furnace combustion section, and an exhaust gas treatment section; The fuel preparation section includes a liquid hydrogen passage (1), a gas-liquid heat exchanger (2), an air passage (3), and a coal mill (4); the liquid hydrogen passage (1) is connected to the tube-side inlet of the gas-liquid heat exchanger (2), the tube-side outlet of the gas-liquid heat exchanger (2) is connected to the mixed fuel inlet of the coal mill (4), and the air passage (3) is connected to the air inlet of the coal mill (4); The furnace combustion section includes multiple alternating hydrogen-coal co-combustion zones and pulverized coal main combustion zones. The upper and lower parts of the furnace combustion section are hydrogen-coal co-combustion zones, forming a structure of hydrogen-coal co-combustion zone-pulverized coal main combustion zone-hydrogen-coal co-combustion zone. Above the upper hydrogen-coal co-combustion zone is the burnout zone (10). The hydrogen-coal co-combustion zone, pulverized coal main combustion zone and burnout zone (10) are respectively provided with gas-solid burner nozzles, pulverized coal burner nozzles and burnout air nozzles (7). It also includes a heat exchanger (11) and a steam turbine (12). The heat exchanger (11) is located at the tail of the furnace. The high-temperature steam outlet of the heat exchanger (11) is connected to the inlet of the steam turbine (12). The steam outlet of the steam turbine (12) is connected to the shell-side inlet of the gas-liquid heat exchanger (2). The exhaust gas treatment section includes a purification device (13), a carbon dioxide collection device (14), and a chimney (15) that are sequentially connected to the flue gas outlet of the heat exchanger (11). The carbon dioxide outlet of the carbon dioxide collection device (14) is divided into two paths through the first regulating valve (16). One path is connected to the carbon dioxide storage device (17), and the other path is divided into two paths through the second regulating valve (18). One path is connected to the tube side outlet of the gas-liquid heat exchanger (2), and the other path is divided into two paths again through the third regulating valve (19). One path is connected to the shell side of the gas-liquid heat exchanger (2), and the other path is connected to the liquid hydrogen passage (1).

2. The system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: The coal mill (4) is equipped with an air inlet (4-1), an adjusting plate (4-2), a coarse powder outlet (4-3), a mixed fuel inlet (4-4), and a mixed fuel outlet (4-5). Air enters through the air inlet (4-1) and drives the coal powder to flow. The coarse and fine powders are separated at the adjusting plate (4-2), so that the fine coal powder falls below and the coarse coal powder flows out from the coarse powder outlet (4-3). The mixed gas of hydrogen and carbon dioxide drives the fine coal powder to circulate around the coal drop pipe and is blown out from the mixed fuel outlet (4-5) through the mixed fuel inlet (4-4).

3. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: The combustion section of the furnace is also equipped with several secondary air nozzles and igniters, arranged in a tangential pattern on each wall of the furnace.

4. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: When carbon dioxide and hydrogen are mixed in the gas-liquid heat exchanger (2), the deflagration pressure and combustion intensity of hydrogen are effectively suppressed, and at the same time, mixing with pulverized coal can achieve the purpose of low carbon emissions.

5. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: The structure of the gas-liquid heat exchanger (2) connected to the liquid hydrogen passage (1) is designed to utilize the heat from the cold source at the tail end of the steam turbine, thereby improving the overall thermal efficiency and reducing the need for geographical restrictions on coal-fired units.

6. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: In the coal mill (4), coal powder of different fineness is divided into two streams. Air drives the coarse coal powder, and a mixed airflow of hydrogen and carbon dioxide drives the fine coal powder. The coarse coal powder airflow is driven by the fully combusted hydrogen and fine coal powder airflow, thereby further saving metal consumables in the coal mill.

7. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: The exhaust gas treatment section is equipped with a carbon dioxide collection device (14) and a carbon dioxide storage device (17) to provide the carbon dioxide required in the pipeline during the initial start-up process, to provide the carbon dioxide flow required to regulate the hydrogen flow, and to provide the initial heat for liquid hydrogen heat exchange in the gas-liquid heat exchanger (2).

8. A system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace according to claim 1, characterized in that: The exhaust gas treatment section utilizes the heat-insulating properties of carbon dioxide to encapsulate the carbon dioxide in the liquid hydrogen pipeline (1), thereby providing a good temperature space for the liquid hydrogen, making its heat exchange more stable, achieving the purpose of utilizing carbon dioxide and meeting the low-carbon requirements.

9. A control method for a system based on the combustion of pulverized coal mixed with hydrogen in a coal-fired furnace, as described in any one of claims 1 to 8, characterized in that: Includes the following steps: Step 1, fuel introduction: Liquid hydrogen fuel is supplied by liquid hydrogen passage (1) into gas-liquid heat exchanger (2), and the steam after work is provided with heat to turn liquid hydrogen into gas; gaseous hydrogen is mixed with carbon dioxide provided by carbon dioxide storage device (17) and then introduced into coal mill (4). Cold air is supplied by the air passage (3) and enters the coal mill (4) through the air inlet (4-1), driving the coal powder to flow. The coarse and fine powders are separated by the regulating plate (4-2), with the coarse coal powder being discharged through the coarse powder outlet (4-3) and the fine coal powder falling down. A mixed flow of hydrogen and carbon dioxide is sent into the coal mill (4) through the mixed fuel inlet (4-4), driving the fine coal powder that meets the conditions to enter the pipeline from the mixed fuel outlet (4-5). The mixed fuel of hydrogen and fine coal powder is fed into the furnace through the gas-solid burner nozzle, and the mixed fuel of air and coarse coal powder is fed into the furnace through the pulverized coal burner nozzle. Step 2, combustion in the furnace area: The furnace is divided into a hydrogen-coal co-combustion zone, a pulverized coal main combustion zone, and a burnout zone (10); the mixed fuel of hydrogen and fine pulverized coal is fed into the furnace through the gas-solid burner nozzle and burned in the hydrogen-coal co-combustion zone, and the mixed fuel of air and coarse pulverized coal is fed into the furnace through the pulverized coal burner nozzle and burned in the pulverized coal main combustion zone. The remaining fuel is fully burned in the burnout zone (10); after the high-temperature flue gas is heated by the heat exchanger (11), the high-temperature steam flows into the steam turbine (12) to do work, and the steam after doing work enters the gas-liquid heat exchanger (2) for heat exchange; Step 3, storage and utilization of carbon dioxide: After heat exchange, the flue gas is purified by the purification equipment (13) to remove dust, desulfurize and denitrify to meet the standards; the purified flue gas flows through the carbon dioxide collection device (14), so that the carbon dioxide in the flue gas is diverted and passes through the first regulating valve (16), while the remaining gas is discharged through the chimney (15); the carbon dioxide passing through the first regulating valve (16) is divided into two paths, one of which enters the carbon dioxide storage device (17) to reach its maximum capacity, and the other path goes to the second regulating valve (18). The second regulating valve (18) controls the diversion of carbon dioxide, one of which goes into the liquid hydrogen passage (1) to play a heat preservation role, and the other path goes into the gaseous hydrogen pipeline.

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