Power station boiler oxygen-enriched hydrogen-ammonia system and working method thereof

Abstract

The present application belongs to the field of flexible peak regulation and carbon reduction of thermal power units, and discloses a power station boiler oxygen-rich hydrogen-ammonia system and a working method thereof, which comprises a boiler, two burners at the lower part of the boiler are micro-hydrogen burners; the combustion outlet of the micro-hydrogen burner is connected with the lower furnace of the boiler, a hydrogen main gun is obliquely inserted into the inner side of the pulverized coal air chamber of the micro-hydrogen burner, a hydrogen ignition gun is located in the middle of the pulverized coal air chamber of the micro-hydrogen burner, and the hydrogen main gun and the hydrogen ignition gun are connected with a hydrogen supply system; the boiler is provided with secondary air nozzles above and below each burner, wherein the secondary air nozzle below the lowermost micro-hydrogen burner is set as a lower secondary air nozzle, the secondary air nozzle above is set as an ammonia-doped secondary air nozzle, the secondary air nozzles above and below the uppermost micro-hydrogen burner are both set as ammonia-doped secondary air nozzles, and the ammonia gas inlet of the ammonia-doped secondary air nozzle is connected with an ammonia supply system. The present application can combine hydrogen-ammonia combustion and air oxygen-rich combustion to solve the problem of unstable combustion under low load.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of flexible peak regulation and carbon reduction of thermal power units, and particularly relates to an oxygen-rich hydrogen-ammonia system for a power plant boiler and a working method thereof. BACKGROUND

[0002] Currently, three reconstruction construction methods are proposed in the action plan for low-carbon reconstruction and construction of coal-fired power plants: one is biomass blending combustion; two is green ammonia blending combustion, which uses surplus electricity from renewable energy sources such as wind power and solar power to produce green hydrogen through water electrolysis and synthesize green ammonia, and implements green ammonia blending combustion in coal-fired units; three is carbon capture, utilization and storage.

[0003] Currently, there are NH3 fuel power generation projects that use renewable green NH3 for power generation.

[0004] However, when ammonia fuel is blended with coal for combustion, the combustion characteristics are not as good as conventional gas fuels, and blending ammonia combustion reduces the adiabatic flame temperature in the furnace. According to relevant research, blending ammonia with hydrogen, which has better combustion performance, can effectively improve the combustion characteristics of the fuel and meet the low-carbon demand. At the same time, compared with green ammonia blending combustion, direct green hydrogen blending combustion has low cost and reduces the synthesis of ammonia, but hydrogen is difficult to store and transport, and is chemically active, flammable and explosive, so it is necessary to carry out preliminary technical research on coal-fired unit blending hydrogen. Air-rich combustion can enhance the combustion process of ammonia, has the advantages of strong combustion and high combustion efficiency, and has significant application value from a technical point of view.

[0005] When a coal-fired boiler is deeply regulated, unstable combustion problems occur at low load, and excess electricity occurs when the boiler is flexibly operated, which also results in waste of this part of electricity. Therefore, how to combine hydrogen-ammonia blending combustion with air-rich combustion to solve the problem of unstable combustion at low load, and use this part of electricity to generate green ammonia and green hydrogen to meet the low-carbon operation requirements of the boiler, etc. has great significance for the deep peak regulation and carbon reduction operation of the boiler. SUMMARY

[0006] To solve the problems in the prior art, the present application aims to provide an oxygen-rich hydrogen-ammonia system for a power plant boiler and a working method thereof, which can combine hydrogen-ammonia blending combustion with air-rich combustion to solve the problem of unstable combustion at low load, and use this part of electricity to generate green ammonia and green hydrogen to meet the low-carbon operation requirements of the boiler, which has great significance for the deep peak regulation and carbon reduction operation of the boiler.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0008] The oxygen-rich hydrogen-ammonia mixing system of a power plant boiler comprises a boiler, an electrolytic water system, a hydrogen supply system, an oxygen supply system and an ammonia supply system, the hydrogen outlet of the electrolytic water system is connected with the hydrogen supply system and the ammonia supply system, the oxygen outlet of the electrolytic water system is connected with the oxygen supply system, the boiler is provided with five burners from top to bottom, wherein the upper three burners are coal powder burners and the lower two burners are micro hydrogen burners, the micro hydrogen burners replace the original coal powder burners, hydrogen is injected when the micro hydrogen burners are ignited, and the micro hydrogen burners are used as coal powder burners in normal operation; the combustion outlet of the micro hydrogen burner is connected with the lower furnace of the boiler, the hydrogen main gun is obliquely inserted into the inner side of the coal powder air chamber of the micro hydrogen burner, the hydrogen ignition gun is located in the middle of the coal powder air chamber of the micro hydrogen burner, the hydrogen main gun and the hydrogen ignition gun are connected with the hydrogen supply system, and the oxygen inlet of the micro hydrogen burner is connected with the oxygen supply system; the boiler is provided with secondary air injection ports above and below each burner, wherein the secondary air injection port below the lowermost micro hydrogen burner is set as a lower secondary air injection port, the secondary air injection port above the lowermost micro hydrogen burner is set as an ammonia-mixed secondary air injection port, the secondary air injection ports above and below the uppermost micro hydrogen burner are both set as ammonia-mixed secondary air injection ports, and the ammonia inlet of the ammonia-mixed secondary air injection port is connected with the ammonia supply system.

[0009] Preferably, the micro hydrogen burner comprises a hydrogen ignition gun, a hydrogen main gun, a first coal powder burner, an inlet air bellow and a hydrogen gas collecting ring; the combustion ends of the hydrogen ignition gun and the hydrogen main gun both extend to the combustion end of the first coal powder burner, the hydrogen main gun is connected with the hydrogen supply system through the hydrogen gas collecting ring; the hydrogen ignition gun is connected with the hydrogen supply system; the inlet air bellow is connected with the oxygen supply system and a high-pressure air supply system, and the outlet of the inlet air bellow is connected with the combustion-supporting gas inlet of the first coal powder burner.

[0010] Preferably, the high-pressure air supply system adopts a high-pressure fan, and the outlet of the high-pressure fan is connected with the air inlet of the inlet air bellow through a high-pressure air pipeline system.

[0011] Preferably, the ammonia-mixed secondary air injection port comprises an ammonia gas injection port and an outer secondary air injection port, the ammonia gas injection port comprises an ammonia gas cyclone nozzle, the outer secondary air injection port is connected with a secondary air pipeline system, and the ammonia gas cyclone nozzle is connected with the ammonia supply system.

[0012] Preferably, the hydrogen supply system comprises a hydrogen storage tank and a hydrogen main pipeline system, the hydrogen storage tank is connected with the electrolytic water system and the hydrogen main gun through the hydrogen main pipeline system, a hydrogen ignition branch pipeline system is connected on the hydrogen main pipeline system, and the hydrogen ignition branch pipeline system is connected with the hydrogen ignition gun.

[0013] Preferably, the hydrogen main pipeline system is sequentially provided with a first filter, a first pressure gauge, a first pressure regulating valve, a first flow meter, a first hand ball valve, a first cut-off valve, a second cut-off valve, a first flow regulating valve and a flame arrester downstream of the hydrogen storage tank, a first differential pressure transmitter is arranged at the first pressure regulating valve of the hydrogen main pipeline system, the hydrogen ignition branch system is connected to the hydrogen main pipeline system between the first cut-off valve and the second cut-off valve, and the hydrogen ignition branch system is sequentially provided with a second hand ball valve, an electromagnetic valve and an ignition electromagnetic valve.

[0014] Preferably, the oxygen supply system comprises an oxygen storage tank and an oxygen pipeline system, the oxygen storage tank is connected to the electrolytic water system and the micro hydrogen burner through the oxygen pipeline system, the oxygen pipeline system is sequentially provided with a second filter, a second pressure gauge, a second pressure regulating valve, a second flow meter, a third hand ball valve, a third cut-off valve and a second flow regulating valve downstream of the oxygen storage tank, and a second differential pressure transmitter is arranged at the second pressure regulating valve of the oxygen pipeline system.

[0015] Preferably, the ammonia supply system comprises an ammonia synthesis system, an ammonia storage tank and an ammonia pipeline system, the ammonia synthesis system is connected to the hydrogen outlet of the electrolytic water system, the ammonia storage tank is connected to the ammonia synthesis system and the ammonia-doped secondary air nozzle through the ammonia pipeline system, the ammonia pipeline system is sequentially provided with a third filter, a third pressure gauge, a third pressure regulating valve, a third flow meter, a fourth hand ball valve, a fourth cut-off valve and a third flow regulating valve downstream of the ammonia storage tank, and a third differential pressure transmitter is arranged at the third pressure regulating valve of the ammonia pipeline system.

[0016] Preferably, the boiler is a four-corner combustion type,

[0017] The working method of the power station boiler oxygen-enriched hydrogen-ammonia system according to the application has the following processes:

[0018] When the boiler is in flexible peak regulation, the surplus electricity is used to electrolyze water by the electrolytic water system to generate green hydrogen and green oxygen, part of the hydrogen is provided to the hydrogen supply system, and the other part of the hydrogen is provided to the ammonia supply system for synthesizing ammonia;

[0019] When the boiler is in low-load operation, the hydrogen of the hydrogen supply system is divided into two paths to provide hydrogen to the hydrogen main gun and the hydrogen ignition gun, respectively, and the hydrogen entering the hydrogen main gun is mixed with ammonia in the furnace;

[0020] The ammonia provided by the ammonia supply system is mixed with the secondary air and enters the furnace through the ammonia-doped secondary air nozzle to burn in the furnace;

[0021] The oxygen provided by the ammonia supply system enters the micro hydrogen burner and is mixed with high-pressure air to enter the furnace, so that the lower part of the furnace is in an oxygen-rich environment, and the hydrogen-ammonia combustion is assisted.

[0022] The application has the following beneficial effects:

[0023] The present application produces green hydrogen and green oxygen by utilizing the surplus electricity during the flexible peak regulation of the boiler. Green ammonia produced by part of the green hydrogen is mixed and burned in the furnace, and another part of the green hydrogen directly enters the furnace to participate in the ammonia / coal blending combustion. Through hydrogen-ammonia blending combustion, the combustion characteristics of the fuel are improved. Since the adiabatic flame temperature is low when ammonia gas is burned, green oxygen produced by electrolysis of water using surplus electricity is used to enter the furnace, so that the content of nitrogen in the flue gas that does not participate in the reaction is reduced, the flame temperature is increased and the free radical concentration is increased, and the combustion process of ammonia is enhanced. Through hydrogen-ammonia blending combustion in an oxygen-rich environment, the flame combustion stability is effectively improved, the flame temperature is maintained, and the problem of unstable combustion during low-load operation of the boiler is solved. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0025] Figure 1 is a burner arrangement diagram of oxygen-enriched hydrogen-ammonia combustion in a single-angle burner in the embodiment of the present application.

[0026] Figure 2 is a PID diagram of the combustion system of oxygen-enriched hydrogen-ammonia combustion in a single-angle burner in the embodiment of the present application.

[0027] Wherein, 1-electrolysis water device, 2-hydrogen storage tank, 3-2-second filter, 3-3-third filter, 3-4-first filter, 4-1-first pressure gauge, 4-2-second pressure gauge, 4-3-third pressure gauge, 5-1-first differential pressure transmitter, 5-2-second differential pressure transmitter, 5-3-third differential pressure transmitter, 6-1-first pressure regulating valve, 6-2-second pressure regulating valve, 6-3-third pressure regulating valve, 7-1-first flow meter, 7-2-second flow meter, 7-3-third flow meter, 8-1-first manual ball valve, 8-2-fifth manual ball valve, 8-3-sixth manual ball valve, 8-4-third manual ball valve, 8-5-fourth manual ball valve, 8-6-seventh manual ball valve, 8-7-eighth manual ball valve, 8-8-second manual ball valve, 9-1-first cut-off valve, 9-2-second cut-off valve, 9-3-third cut-off valve, 9-4-fourth cut-off valve, 10-1-hydrogen release solenoid valve, 10-2-ammonia release solenoid valve, 10-3-oxygen release solenoid valve, 10-5-solenoid valve, 10-6-ignition solenoid valve, 11-1-first flow regulating valve, 11-2-second flow regulating valve, 11-3-third flow regulating valve, 12-purging system, 13-fire damper, 14-pulverized coal burner, 15-micro hydrogen burner, 16-ammonia nozzle, 17-high pressure fan, 18-boiler, 19-secondary air nozzle, 19-1-ammonia mixed secondary air nozzle, 19-2-lower secondary air nozzle, 20-hydrogen main pipeline system, 21-hydrogen ignition branch pipeline system, 22-oxygen pipeline system, 23-high pressure air pipeline system, 24-ammonia pipeline system, 25-ammonia storage tank, 26-oxygen storage tank. DETAILED DESCRIPTION

[0028] According to the technical solution of the present application, those skilled in the art can propose various alternative structures and implementations without changing the spirit of the present application. Therefore, the following detailed description and drawings are only exemplary descriptions of the technical solution of the present application, and should not be considered as the whole or limitation of the technical solution of the present application.

[0029] The present application is suitable for flexible peak regulation of thermal power generating units, and provides an oxygen-rich ammonia system for a power plant boiler, which is used for preparing green hydrogen and green oxygen by electrolyzing water with surplus electricity when the coal-fired boiler is flexibly regulated, a part of the green hydrogen is used to prepare green ammonia, and the other part of the hydrogen and ammonia is mixed and burned under the condition of oxygen enrichment. Not only the surplus electricity is utilized, but also the problem of unstable combustion during low load operation of the boiler is improved. The system meets the low-carbon requirement and is conducive to low-carbon development. Figure 1 , Figure 1The single-angle combustor oxygen-enriched ammonia-doped combustor arrangement schematic diagram for the embodiment is shown, taking a 300MW unit as an example, the boiler is four-angle combustion mode, and five layers of pulverized coal burners are arranged, and each layer of burner is provided with two secondary air nozzles above and below. The original secondary air nozzle is replaced by the ammonia-doped secondary air nozzle 19-1 in the lower two layers of the original pulverized coal burner, and the lower pulverized coal burner is replaced by the micro-hydrogen burner 15. The micro-hydrogen burner 15 replaces the original pulverized coal burner 14, hydrogen is put into the micro-hydrogen burner 15 during ignition and combustion support, and the micro-hydrogen burner 15 can be used as a pulverized coal burner during normal operation. The combustion outlet of the micro-hydrogen burner 15 is connected with the lower furnace of the boiler, the hydrogen main gun is obliquely inserted into the inner side of the pulverized coal burner pulverized coal air chamber to ensure the heat required for early combustion; the hydrogen ignition gun is located in the middle of the pulverized coal burner pulverized coal air chamber to ensure the early ignition heat of hydrogen.

[0030] Reference Figure 2The power station boiler oxygen-enriched hydrogen-ammonia system comprises a micro-hydrogen burner 15, an electrolytic water system, a hydrogen main pipeline system 20, a hydrogen ignition branch system 21, an oxygen pipeline system 22 and an ammonia pipeline system 24. The hydrogen main pipeline system 20 is sequentially provided with a first filter 3-4, a first pressure gauge 4-1, a first pressure regulating valve 6-1, a first flowmeter 7-1, a first manual ball valve 8-1, a first cut-off valve 9-1, a second cut-off valve 9-2, a first flow regulating valve 11-1 and a flame arrester 13 downstream of a hydrogen storage tank 2. The hydrogen main pipeline system 20 is provided with a first differential pressure transmitter 5-1 at the first pressure regulating valve 6-1. The hydrogen ignition branch system 21 is connected to the hydrogen main pipeline system 20 between the first cut-off valve 9-1 and the second cut-off valve 9-2. The hydrogen ignition branch system 21 is sequentially provided with a second manual ball valve 8-8, an electromagnetic valve 10-5 and an ignition electromagnetic valve. The oxygen supply system comprises an oxygen storage tank 26 and the oxygen pipeline system 22. The oxygen storage tank 26 is connected to the electrolytic water system and the micro-hydrogen burner 15 through the oxygen pipeline system 22. The oxygen pipeline system 22 is sequentially provided with a second filter 3-2, a second pressure gauge 4-2, a second pressure regulating valve 6-2, a second flowmeter 7-2, a third manual ball valve 8-4, a third cut-off valve 9-3 and a second flow regulating valve 11-2 downstream of the oxygen storage tank 26. The oxygen pipeline system 22 is provided with a second differential pressure transmitter 5-2 at the second pressure regulating valve 6-2. The ammonia supply system comprises an ammonia synthesis system, an ammonia storage tank 25 and the ammonia pipeline system 24. The ammonia synthesis system is connected to a hydrogen outlet of the electrolytic water system. The ammonia storage tank 25 is connected to the ammonia synthesis system and an ammonia-doped secondary air nozzle 19-1 through the ammonia pipeline system 24. The ammonia pipeline system 24 is sequentially provided with a third filter 3-3, a third pressure gauge 4-3, a third pressure regulating valve 6-3, a third flowmeter 7-3, a fourth manual ball valve 8-5, a fourth cut-off valve 9-4 and a third flow regulating valve 11-3 downstream of the ammonia storage tank 25. The ammonia pipeline system 24 is provided with a third differential pressure transmitter 5-3 at the third pressure regulating valve 6-3. The micro-hydrogen burner 15 comprises a hydrogen ignition lance 15-1, a hydrogen main lance 15-2, a first pulverized coal burner 15-3, an inlet air box 15-4 and a hydrogen gas collecting ring 15-5. The combustion ends of the hydrogen ignition lance 15-1 and the hydrogen main lance 15-2 extend to the combustion end of the first pulverized coal burner 15-3. The hydrogen main lance 15-2 is connected to the outlet of the hydrogen main pipeline system 20 through the hydrogen gas collecting ring 15-5. The hydrogen ignition lance 15-1 is connected to the outlet of the hydrogen ignition branch system 21. The inlet air box 15-4 is connected to the outlet of the oxygen pipeline system 22 and a high-pressure air supply system. The outlet of the inlet air box 15-4 is connected to the combustion gas inlet of the first pulverized coal burner 15-3. The high-pressure air supply system adopts a high-pressure fan 17. The outlet of the high-pressure fan 17 is connected to the air inlet of the inlet air box 15-4 through a high-pressure air pipeline system 23.The ammonia-doped secondary air injection port 19-1 includes an ammonia gas injection port 16 and an outer secondary air injection port 16-2, the ammonia gas injection port 16 comprising an ammonia gas swirl nozzle 16-1, the outer secondary air injection port 16-2 being connected with a secondary air pipeline system, and the ammonia gas swirl nozzle 16-1 being connected with an ammonia supply system. The electrolytic water system comprises an electrolytic water device 1.

[0031] The present application firstly proposes that oxygen and hydrogen generated by electrolysis of surplus electricity are used to burn in the furnace, which can enhance the deep peak shaving capacity, part of the pulverized coal is ignited by hydrogen in the burner, and can burn quickly after entering the furnace, which can effectively improve the furnace temperature and furnace heat load, realize the ultra-low load peak shaving of the boiler, and enhance the deep peak shaving capacity of the thermal power unit; enhance the fuel flexibility, use hydrogen to ignite the pulverized coal, and enrich the oxygen to strengthen the combustion of the pulverized coal, which can effectively improve the adaptability of the boiler to coal types.

[0032] When the boiler is in flexible peak shaving, green hydrogen and green oxygen generated by electrolysis of water are used to meet the gas consumption of the boiler in low load operation. Part of the hydrogen enters the hydrogen main pipeline system 20 and enters the hydrogen storage tank 2, another part of the hydrogen and nitrogen are synthesized into green ammonia, enter the ammonia pipeline system 24, and enter the ammonia storage tank 25; the oxygen enters the oxygen storage tank 26.

[0033] When the boiler is in low load operation, in order to solve the problem of unstable combustion, the operation mode of the present combustion system is as follows:

[0034] The hydrogen is discharged from the hydrogen storage tank 2, passes through the first filter 3-4, the first pressure gauge 4-1, the first differential pressure transmitter 5-1, the first pressure regulating valve 6-1, the first flow meter 7-1, the first manual ball valve 8-1, and the first shut-off valve 9-1, and is divided into two paths, one path enters the second shut-off valve 9-2, the first flow regulating valve 11-1 and the flame arrester 13, and then enters the hydrogen gas collecting ring 15-5; the other path enters the hydrogen ignition branch system 21, passes through the second manual ball valve 8-8, the electromagnetic valve 10-5, the ignition electromagnetic valve 10-6, and finally enters the hydrogen ignition gun 15-1, and finally enters the furnace to be mixed with ammonia gas.

[0035] The ammonia gas is discharged from the ammonia storage tank 25, passes through the third filter 3-3, the third pressure gauge 4-3, the third differential pressure transmitter 5-3, the third pressure regulating valve 6-3, the third flow meter 7-3, the fourth manual ball valve 8-5, the fourth shut-off valve 9-4, and the third flow regulating valve 11-3, enters the ammonia gas injection port 16, is mixed with secondary air, enters the furnace through the ammonia-doped secondary air injection port, and is burned.

[0036] The oxygen is output from the oxygen storage tank 26, passes through the second filter 3-2, the second pressure gauge 4-2, the second differential pressure transmitter 5-2, the second pressure regulating valve 6-2, the second flow meter 7-2, the sixth manual ball valve 8-3, the third shut-off valve 9-3, the second flow regulating valve 11-2, and finally enters the micro-hydrogen burner 15, is mixed with high-pressure air, enters the furnace, and makes the lower part of the burner an oxygen-rich environment, thereby assisting the hydrogen-ammonia combustion.

[0037] The present application produces green hydrogen and green oxygen by utilizing the surplus electricity during flexible peak regulation of the boiler. A part of the green hydrogen is used to produce green ammonia which is mixed and burned in the furnace, and another part of the green hydrogen is directly introduced into the furnace to participate in the ammonia / coal mixed combustion. Through hydrogen-ammonia mixed combustion, the combustion characteristics of the fuel are improved. Since the adiabatic flame temperature is low when ammonia gas is burned, the green oxygen produced by electrolysis of water using surplus electricity is introduced into the furnace, so that the content of nitrogen gas which does not participate in the reaction in the flue gas is reduced, the flame temperature is increased, the free radical concentration is increased, and the combustion process of ammonia is enhanced. Through hydrogen-ammonia mixed combustion in an oxygen-rich environment, the flame combustion stability is effectively improved, the flame temperature is maintained, and the problem of unstable combustion during low-load operation of the boiler is solved.

[0038] In order to ensure the safe operation of the system, referring to Figure 2 The present application also provides a purging system 12 and a diffusion system. The purging system 12 is connected with the hydrogen main pipeline system 20, the hydrogen ignition branch pipeline system 21 and the oxygen pipeline system 22, respectively. The pipeline connected with the hydrogen main pipeline system 20, the pipeline connected with the hydrogen ignition branch pipeline system 21 and the pipeline connected with the oxygen pipeline system 22 are respectively provided with a manual ball valve and an electromagnetic valve for controlling the purging. The purging system is used to replace the air in the pipeline with nitrogen in an emergency to reduce the possibility of hydrogen explosion.

[0039] The diffusion system comprises a diffusion pipeline, wherein: the ammonia pipeline system 24 of the ammonia supply system is connected with the diffusion pipeline between the fourth cut-off valve 9-4 and the third flow regulating valve 11-3, the diffusion pipeline is provided with the eighth manual ball valve 8-7 and the ammonia diffusion electromagnetic valve 10-2; in the hydrogen supply system, the hydrogen main pipeline system 20 is connected with the diffusion pipeline in parallel upstream and downstream of the first cut-off valve 9-1, one end of the diffusion pipeline is communicated with the inlet of the first cut-off valve 9-1, the other end of the diffusion pipeline is communicated with the inlet of the second cut-off valve 9-2 and the inlet of the second manual ball valve 8-8, the diffusion pipeline is provided with the hydrogen diffusion electromagnetic valve 10-1, and both ends of the diffusion pipeline are provided with manual ball valves; in the oxygen supply system, the oxygen pipeline system 22 is provided with the diffusion pipeline between the third cut-off valve 9-3 and the second flow regulating valve 11-2, the diffusion pipeline is provided with the fourth manual ball valve 8-5 and the oxygen diffusion electromagnetic valve 10-3 in sequence. In an emergency, the fifth manual ball valve 8-2, the fourth manual ball valve 8-5, the eighth manual ball valve 8-7, the hydrogen diffusion electromagnetic valve 10-1, the ammonia diffusion electromagnetic valve 10-2 and the oxygen diffusion electromagnetic valve 10-3 can be opened, so that the hydrogen, ammonia or oxygen in the pipeline can be effectively discharged, and the system safety can be ensured.

[0040] The system comprises hydrogen, ammonia and oxygen-rich systems, and safety measures are set according to the "Technical Regulations for Boiler Furnace Explosion Prevention of Power Station", such as pressure regulating valves to ensure working pressure, quick cut-off valves to ensure timely closing of fuel in case of accidents, regulating valves to ensure matching of gas required by each load of the boiler, high-pressure fans to ensure high-pressure air required for hydrogen combustion, and automatic protection programs connected to DCS, so as to ensure stable operation of the oxygen-rich hydrogen-doped ammonia system.

[0041] Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0042] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A power station boiler oxygen-enriched hydrogen-ammonia system, characterized in that: The invention comprises a boiler (18), a water electrolysis system, a hydrogen supply system, an oxygen supply system and an ammonia supply system. The hydrogen outlet of the water electrolysis system is connected to the hydrogen supply system and the ammonia supply system, and the oxygen outlet of the water electrolysis system is connected to the oxygen supply system. The boiler (18) is provided with five burners from top to bottom, wherein the three upper burners adopt pulverized coal burners (14), and the two lower burners adopt micro hydrogen burners (15). The micro hydrogen burners (15) replace the original pulverized coal burners. When the micro hydrogen burners (15) are ignited and combustion-supported, hydrogen is added and the micro hydrogen burners (15) are used as pulverized coal burners in normal operation. The combustion outlet of the micro hydrogen burners (15) is connected to the lower furnace of the boiler, and the main hydrogen gun is obliquely inserted into the micro hydrogen burners (15). Inside the pulverized coal air chamber, a hydrogen ignition gun is located in the middle of the pulverized coal air chamber of the micro hydrogen burner (15), the hydrogen main gun and the hydrogen ignition gun are both connected to the hydrogen supply system, and the oxygen inlet of the micro hydrogen burner (15) is connected to the oxygen supply system; the boiler (18) is provided with secondary air nozzles above and below each burner, wherein the secondary air nozzle below the lowest micro hydrogen burner (15) is set as the lower secondary air nozzle, and the upper secondary air nozzle is set as the ammonia-doped secondary air nozzle (19-1), and the upper and lower secondary air nozzles of the uppermost micro hydrogen burner (15) are both set as ammonia-doped secondary air nozzles (19-1), and the ammonia inlet of the ammonia-doped secondary air nozzle (19-1) is connected to the ammonia supply system.

2. The power station boiler oxygen-enriched hydrogen-ammonia system according to claim 1, characterized in that: The micro hydrogen burner (15) comprises a hydrogen ignition gun (15-1), a main hydrogen gun (15-2), a first pulverized coal burner (15-3), an inlet wind box (15-4) and a hydrogen gas collecting ring (15-5); the combustion ends of the hydrogen ignition gun (15-1) and the main hydrogen gun (15-2) both extend to the combustion end of the first pulverized coal burner (15-3); the main hydrogen gun (15-2) is connected to a hydrogen supply system via a hydrogen gas collecting ring (15-5); the hydrogen ignition gun (15-1) is connected to the hydrogen supply system; the inlet wind box (15-4) is connected to an oxygen supply system and a high-pressure air supply system; and the outlet of the inlet wind box (15-4) is connected to a combustion-supporting gas inlet of the first pulverized coal burner (15-3).

3. The oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 2, characterized in that: The high-pressure air supply system adopts a high-pressure blower (17), and the outlet of the high-pressure blower (17) is connected to the air inlet of the inlet wind box (15-4) through a high-pressure air duct system (23).

4. The oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 1, characterized in that: The ammonia-doped secondary air nozzle (19-1) includes an ammonia nozzle (16) and an external secondary air nozzle (16-2), the ammonia nozzle (16) includes an ammonia cyclone nozzle (16-1), the external secondary air nozzle (16-2) is connected to the secondary air piping system, and the ammonia cyclone nozzle (16-1) is connected to the ammonia supply system.

5. The oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 1, characterized in that: The hydrogen supply system comprises a hydrogen storage tank (2) and a hydrogen main line system (20); the hydrogen storage tank (2) is connected to the water electrolysis system and the hydrogen main gun via the hydrogen main line system (20); the hydrogen main line system (20) is connected to a hydrogen ignition branch line system (21); and the hydrogen ignition branch line system (21) is connected to the hydrogen ignition gun.

6. The oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 5, characterized in that: The hydrogen main line system (20) is provided with a first filter (3-4), a first pressure gauge (4-1), a first pressure regulating valve (6-1), a first flow meter (7-1), a first manual ball valve (8-1), a first shut-off valve (9-1), a second shut-off valve (9-2), a first flow regulating valve (11-1) and a flame arrester (13) in sequence downstream of the hydrogen storage tank (2). A first differential pressure transmitter (5-1) is provided at the first pressure regulating valve (6-1) on the hydrogen main line system (20). The connection point between the hydrogen ignition branch line system (21) and the hydrogen main line system (20) is between the first shut-off valve (9-1) and the second shut-off valve (9-2). The hydrogen ignition branch line system (21) is provided with a second manual ball valve (8-8), a solenoid valve (10-5) and an ignition solenoid valve in sequence.

7. The oxygen-enriched hydrogen-doped ammonia system for power station boilers according to claim 1, characterized in that: The oxygen supply system includes an oxygen storage tank (26) and an oxygen pipeline system (22). The oxygen storage tank (26) is connected to the water electrolysis system and the micro-hydrogen burner (15) through the oxygen pipeline system (22). The oxygen pipeline system (22) is provided with a second filter (3-2), a second pressure gauge (4-2), a second pressure regulating valve (6-2), a second flow meter (7-2), a third manual ball valve (8-4), a third shut-off valve (9-3), and a second flow regulating valve (11-2) in sequence downstream of the oxygen storage tank (26). The oxygen pipeline system (22) is provided with a second differential pressure transmitter (5-2) at the second pressure regulating valve (6-2).

8. The oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 1, characterized in that: The ammonia supply system includes an ammonia synthesis system, an ammonia storage tank (25) and an ammonia pipeline system (24). The ammonia synthesis system is connected to the hydrogen outlet of the water electrolysis system. The ammonia storage tank (25) is connected to the ammonia synthesis system and the ammonia-doped secondary air nozzle (19-1) through the ammonia pipeline system (24). A third filter (3-3), a third pressure gauge (4-3), a third pressure regulating valve (6-3), a third flow meter (7-3), a fourth manual ball valve (8-5), a fourth shut-off valve (9-4) and a third flow regulating valve (11-3) are sequentially provided on the ammonia pipeline system (24) downstream of the ammonia storage tank (25). A third differential pressure transmitter (5-3) is provided on the ammonia pipeline system (24) at the third pressure regulating valve (6-3).

9. The oxygen-enriched hydrogen-doped ammonia system for power station boilers according to claim 1, characterized in that: The boiler (18) is a four-corner combustion method.

10. The operating method of the oxygen-enriched hydrogen-doped ammonia system for a power station boiler according to any one of claims 1 to 9, characterized in that: The process includes the following: When the boiler is in a flexible peak-shaving mode, the excess electricity is used to electrolyze water through the water electrolysis system to produce green hydrogen and green oxygen. Part of the hydrogen is provided to the hydrogen supply system, and the other part is provided to the ammonia supply system for ammonia synthesis. When the boiler is running at low load, the hydrogen in the hydrogen supply system is divided into two routes, supplying hydrogen to the hydrogen main gun and the hydrogen ignition gun respectively. The hydrogen entering the hydrogen main gun is mixed with ammonia in the furnace; Ammonia gas provided by the ammonia supply system is mixed with secondary air and enters the furnace through the ammonia-mixed secondary air nozzle (19-1) for combustion; The oxygen provided by the ammonia supply system enters the micro hydrogen burner (15), is mixed with the high pressure air, and enters the furnace, so that the lower part of the furnace is an oxygen-rich environment, which assists the combustion of hydrogen and ammonia.

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