Power station boiler oxygen enrichment and hydrogen ammonia doping system and working method thereof

Abstract

The invention belongs to the field of flexible peak regulation and carbon reduction of thermal power generating units, and discloses a power station boiler oxygen-enriched hydrogen-ammonia-doped system and a working method thereof.The power station boiler oxygen-enriched hydrogen-ammonia-doped system comprises a boiler, and two combustors on the lower portion of the boiler are micro-hydrogen combustors; a combustion outlet of the micro-hydrogen combustor is connected with a lower hearth of the boiler, the hydrogen main gun is obliquely inserted into the inner side of a pulverized coal air chamber of the micro-hydrogen combustor, the hydrogen ignition gun is located in the middle of the pulverized coal air chamber of the micro-hydrogen combustor, and the hydrogen main gun and the hydrogen ignition gun are both connected with the hydrogen supply system. The boiler is provided with secondary air nozzles above and below each burner, the secondary air nozzle below the lowermost micro-hydrogen burner is arranged as a lower secondary air nozzle, the secondary air nozzle above the lowermost micro-hydrogen burner is arranged as an ammonia-doped secondary air nozzle, and the secondary air nozzle below the lowermost micro-hydrogen burner is arranged as an ammonia-doped secondary air nozzle. The secondary air nozzles above and below the uppermost micro-hydrogen burner are ammonia-doped secondary air nozzles, and ammonia gas inlets of the ammonia-doped secondary air nozzles are connected with an ammonia supply system. The problem of unstable combustion under low load can be solved by combining hydrogen-doped ammonia combustion and air oxygen-enriched combustion supporting.

Description

Technical Field

[0001] The present invention belongs to the field of flexible peak regulation and carbon reduction of thermal power units, and specifically relates to an oxygen-enriched hydrogen-ammonia system for a power station boiler and a working method thereof. Background Art

[0002] At present, the action plan for the low-carbon transformation and construction of coal-fired power has proposed three transformation and construction methods: one is biomass co-firing; the second is green ammonia co-firing, which uses surplus electricity from renewable energy sources such as wind power and solar power generation to produce green hydrogen and synthesize green ammonia through water electrolysis, and implements coal-fired units to burn green ammonia for power generation; the third is carbon capture, utilization and storage.

[0003] At present, NH3 fuel power generation projects have been deployed, using renewable green NH3 for power generation.

[0004] However, when ammonia fuel is mixed with coal for combustion, its combustion characteristics are not as good as those of conventional gas fuel, and the combustion of ammonia will reduce the adiabatic flame temperature in the furnace. According to relevant research, the combustion of ammonia and hydrogen with better combustion performance can effectively improve the combustion characteristics of the fuel and meet the low-carbon demand. At the same time, compared with the combustion of green ammonia, the direct combustion of green hydrogen has a lower cost and reduces the link of synthetic ammonia. However, the storage and transportation of hydrogen is more difficult, and its chemical properties are active, easy to burn and explode. Therefore, it is necessary to carry out preliminary technical research on the hydrogen blending of coal-fired power units. Air oxygen-enriched combustion can enhance the combustion process of ammonia, and has the advantages of significant intense combustion and high combustion efficiency. From a technical perspective, it has significant application value.

[0005] When coal-fired boilers are deeply peak-shifted, unstable combustion will occur under low loads, and there will be surplus electricity when the boiler is flexibly operated, which will also be wasted. Therefore, how to combine hydrogen-ammonia combustion with air-enriched oxygen combustion to solve the problem of unstable combustion under low loads, and use this part of electricity to generate green ammonia and green hydrogen to meet the requirements of low-carbon operation of boilers is of great significance to the deep peak-shifting and carbon-reducing operation of boilers. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide an oxygen-enriched hydrogen-ammonia system for power station boilers and a working method thereof. The present invention can combine hydrogen-enriched ammonia combustion with air oxygen-enriched combustion to solve the problem of unstable combustion under 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 is of great significance to the deep peak regulation and carbon reduction operation of the boiler.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A power station boiler oxygen-enriched hydrogen-ammonia system comprises a boiler, 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 is provided with five burners from top to bottom, wherein the three upper burners are pulverized coal burners, and the two lower burners are micro-hydrogen burners. The micro-hydrogen burners replace the original pulverized coal burners. Hydrogen is added when the micro-hydrogen burners are ignited and combustion-supported, and the micro-hydrogen burners are used as pulverized coal burners in normal operation. The combustion outlet of the micro-hydrogen burner is connected to the lower furnace of the boiler, and the hydrogen is added to the lower furnace. The main gun is inserted obliquely into the inner side of the pulverized coal air chamber of the micro hydrogen burner, the hydrogen ignition gun is located in the middle of the pulverized coal air chamber of the micro hydrogen burner, 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 is connected to the oxygen supply system; the boiler is provided with secondary air nozzles above and below each burner, wherein the secondary air nozzle below the lowest micro hydrogen burner is set as the lower secondary air nozzle, and the upper secondary air nozzle is set as the ammonia-doped secondary air nozzle, and the upper and lower secondary air nozzles of the uppermost micro hydrogen burner are both set as ammonia-doped secondary air nozzles, and the ammonia inlet of the ammonia-doped secondary air nozzle is connected to the ammonia supply system.

[0008] Preferably, the micro hydrogen burner includes a hydrogen ignition gun, a hydrogen main gun, a first pulverized coal burner, an inlet bellows 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 pulverized coal burner, and the hydrogen main gun is connected to the hydrogen supply system through the hydrogen gas collecting ring; the hydrogen ignition gun is connected to the hydrogen supply system; the inlet bellows is connected to the oxygen supply system and the high-pressure air supply system, and the outlet of the inlet bellows is connected to the combustion-supporting gas inlet of the first pulverized coal burner.

[0009] Preferably, the high-pressure air supply system adopts a high-pressure blower, and the outlet of the high-pressure blower is connected to the air inlet of the inlet wind box through a high-pressure air duct system.

[0010] Preferably, the ammonia-doped secondary air nozzle includes an ammonia nozzle and an external secondary air nozzle, the ammonia nozzle includes an ammonia cyclone nozzle, the external secondary air nozzle is connected to the secondary air duct system, and the ammonia cyclone nozzle is connected to the ammonia supply system.

[0011] Preferably, the hydrogen supply system includes a hydrogen storage tank and a hydrogen main line system, the hydrogen storage tank is connected to the water electrolysis system and the hydrogen main gun through the hydrogen main line system, the hydrogen main line system is connected to a hydrogen ignition branch system, and the hydrogen ignition branch system is connected to the hydrogen ignition gun.

[0012] Preferably, the hydrogen main line system is provided with a first filter, a first pressure gauge, a first pressure regulating valve, a first flow meter, a first manual ball valve, a first cut-off valve, a second cut-off valve, a first flow regulating valve and a flame arrester in sequence downstream of the hydrogen storage tank; a first differential pressure transmitter is provided at the first pressure regulating valve on the hydrogen main line system; the connection point between the hydrogen ignition branch system and the hydrogen main line system is between the first cut-off valve and the second cut-off valve; and a second manual ball valve, a solenoid valve and an ignition solenoid valve are provided in sequence on the hydrogen ignition branch system.

[0013] Preferably, the oxygen supply system includes an oxygen storage tank and an oxygen pipeline system, the oxygen storage tank is connected to the water electrolysis system and the micro-hydrogen burner through the oxygen pipeline system, the oxygen pipeline system is provided with a second filter, a second pressure gauge, a second pressure regulating valve, a second flow meter, a third manual ball valve, a third shut-off valve, and a second flow regulating valve in sequence downstream of the oxygen storage tank, and the oxygen pipeline system is provided with a second differential pressure transmitter at the second pressure regulating valve.

[0014] Preferably, the ammonia supply system includes 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 water electrolysis system. The ammonia storage tank is connected to the ammonia synthesis system and the ammonia-doped secondary air nozzle through the ammonia pipeline system. A third filter, a third pressure gauge, a third pressure regulating valve, a third flow meter, a fourth manual ball valve, a fourth shut-off valve and a third flow regulating valve are sequentially provided on the ammonia pipeline system downstream of the ammonia storage tank. A third differential pressure transmitter is provided on the ammonia pipeline system at the third pressure regulating valve.

[0015] Preferably, the boiler is a four-corner combustion type. The working method of the oxygen-enriched hydrogen-ammonia system for power station boilers of the present invention comprises the following steps: When the boiler is in the flexible peak load regulation mode, the surplus electricity is used to electrolyze water through the water electrolysis system to produce green hydrogen and green oxygen, of which part of the hydrogen is provided to the hydrogen supply system and the other part is provided to the ammonia supply system for synthesizing ammonia. When the boiler is running at low load, the hydrogen in the hydrogen supply system is divided into two routes, which provide 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 for combustion; The oxygen provided by the ammonia supply system enters the micro-hydrogen burner, mixes with the high-pressure air, and enters the furnace, making the lower part of the furnace an oxygen-rich environment to assist the combustion of hydrogen and ammonia.

[0016] The present invention has the following beneficial effects: The present invention produces green hydrogen and green oxygen by utilizing the surplus electricity during the flexible peak-shaving of the boiler. A portion of the green hydrogen is used to produce green ammonia which enters the furnace for blending, and the other portion of the green hydrogen directly enters the furnace to participate in the ammonia / coal blending. The combustion characteristics of the fuel are improved by blending hydrogen and ammonia. Since ammonia combustion will have the problem of low adiabatic flame temperature, the green oxygen produced by the electrolysis of water using surplus electricity enters the furnace, which reduces the nitrogen content in the flue gas that does not participate in the reaction, increases the flame temperature and the concentration of free radicals, and enhances the combustion process of ammonia. By blending hydrogen and ammonia in an oxygen-rich environment, the flame combustion stability is effectively improved, a good flame temperature is maintained, and the problem of unstable combustion when the boiler is running at low load is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a schematic diagram of the burner arrangement of a single-angle burner for oxygen-enriched hydrogen-doped ammonia in an embodiment of the present invention.

[0019] Figure 2 It is the PID diagram of the combustion system of oxygen-enriched hydrogen-ammonia mixed with a single-angle burner in an embodiment of the present invention.

[0020] Among them, 1- water electrolysis 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 Valve, 9-3-third shut-off valve, 9-4-fourth shut-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-purge system, 13-flame arrester, 14-coal powder burner, 15-micro hydrogen burner, 16-ammonia nozzle, 17-high pressure fan, 18-boiler, 19-secondary air nozzle, 19-1-ammonia-doped secondary air nozzle, 19-2-lower secondary air nozzle, 20-hydrogen main pipeline system, 21-hydrogen ignition branch 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

[0021] According to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structures and implementations. Therefore, the following specific implementation methods and drawings are only examples of the technical solution of the present invention and should not be regarded as the entirety of the present invention or the limitation of its technical solution.

[0022] The present invention is applicable to the flexible peak-shaving of thermal power units and provides an oxygen-enriched hydrogen-ammonia system for power station boilers. When the coal-fired boiler is flexible and peak-shaving, the system uses surplus electricity to electrolyze water to prepare green hydrogen and green oxygen. A part of the green hydrogen is used to prepare green ammonia, and the other part of hydrogen and ammonia are mixed and burned. Under oxygen-enriched conditions, not only is the surplus electricity utilized, but the problem of unstable combustion when the boiler is running at low load is also improved. This system meets low-carbon requirements and is conducive to low-carbon development. Figure 1 , Figure 1This is a schematic diagram of the burner arrangement of the single-angle burner oxygen-enriched hydrogen-ammonia in this embodiment. Taking the 300MW unit as an example, the boiler is a four-corner combustion mode, and five layers of pulverized coal burners are arranged. There are secondary air nozzles above and below each layer of burners. The present invention mainly replaces the original secondary air nozzles with ammonia-doped secondary air nozzles 19-1 in the lower two layers of burners of the original pulverized coal burner, and replaces the lower pulverized coal burner with a micro-hydrogen burner 15. The micro-hydrogen burner 15 replaces the original pulverized coal burner 14. Hydrogen is added when the micro-hydrogen burner 15 is ignited and combustion-assisted. It can be used as a pulverized coal burner during normal operation. Among them, the combustion outlet of the micro-hydrogen burner 15 is connected to the lower furnace of the boiler, and the main hydrogen gun is obliquely inserted into the inner side of the pulverized coal burner pulverized wind chamber to ensure the heat required for the early combustion; the hydrogen ignition gun is located in the middle of the pulverized coal burner pulverized wind chamber to ensure the early ignition heat of hydrogen.

[0023] refer to Figure 2The oxygen-enriched hydrogen-ammonia system for power station boilers in this embodiment includes a micro-hydrogen burner 15, a water electrolysis 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 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. The hydrogen main line system 20 is provided with a first differential pressure transmitter 5-1 at the first pressure regulating valve 6-1. The connection point between the hydrogen ignition branch 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 system 21 is provided with a second manual ball valve 8-8, a solenoid valve 10-5 and an ignition solenoid valve in sequence. 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 A 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. 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 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 electrolytic water 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. The ammonia pipeline system 24 is provided with 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 in sequence 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 gun 15-1, a hydrogen main 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 hydrogen main gun 15-2 both extend to the combustion end of the first pulverized coal burner 15-3, and the hydrogen main gun 15-2 is connected to the outlet of the hydrogen main line system 20 through the hydrogen gas collecting ring 15-5; the hydrogen ignition gun 15-1 is connected to the outlet of the hydrogen ignition branch line system 21; the inlet wind box 15-4 is connected to the outlet of the oxygen pipeline system 22 and the high-pressure air supply system, and the outlet of the inlet wind box 15-4 is connected to the combustion-supporting gas inlet of the first pulverized coal burner 15-3, wherein the high-pressure air supply system adopts a high-pressure fan 17, and the outlet of the high-pressure fan 17 is connected to the air inlet of the inlet wind box 15-4 through the high-pressure air pipeline system 23.The ammonia-doped secondary air nozzle 19-1 includes an ammonia nozzle 16 and an external secondary air nozzle 16-2, wherein the ammonia nozzle 16 includes an ammonia cyclone nozzle 16-1, the external secondary air nozzle 16-2 is connected to the secondary air pipeline system, and the ammonia cyclone nozzle 16-1 is connected to the ammonia supply system. The electrolysis water system includes an electrolysis water device 1.

[0024] The present invention proposes for the first time to use the oxygen and hydrogen electrolyzed by surplus electricity to enter the furnace for combustion, which can enhance the deep peak-shaving capability - part of the pulverized coal has been ignited by hydrogen in the burner and can burn quickly after entering the furnace, which can effectively increase the furnace temperature and furnace heat load, realize ultra-low load peak-shaving of the boiler, and enhance the deep peak-shaving capability of the thermal power unit; enhance fuel flexibility - use hydrogen to ignite pulverized coal, enrich the pulverized coal with oxygen to intensify its combustion, and effectively improve the adaptability of boiler coal types.

[0025] When the boiler is in the flexible peak load regulation mode, the surplus electricity is used to electrolyze water to produce green hydrogen and green oxygen to meet the gas consumption when the boiler is running at low load. Among them, part of the hydrogen enters the hydrogen main pipeline system 20 and enters the hydrogen storage tank 2, and the other part of the hydrogen and nitrogen are synthesized into green ammonia, enter the ammonia pipeline system 24, and enter the ammonia storage tank 25; oxygen enters the oxygen storage tank 26.

[0026] When the boiler is running at low load, in order to solve the problem of unstable combustion, the operation mode of this combustion system is as follows: Hydrogen comes out of 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 then 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 solenoid valve 10-5, and the ignition solenoid valve 10-6, and finally enters the hydrogen ignition gun 15-1, and finally enters the furnace to mix and burn with ammonia.

[0027] Ammonia comes out of 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 nozzle 16, mixes with the secondary air, and enters the furnace through the ammonia-mixed secondary air nozzle for combustion.

[0028] Oxygen comes out 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, mixes with the high pressure wind, and enters the furnace, making the lower part of the burner an oxygen-rich environment to assist the combustion of hydrogen and ammonia.

[0029] The present invention produces green hydrogen and green oxygen by utilizing the surplus electricity during the flexible peak-shaving of the boiler. A portion of the green hydrogen is used to produce green ammonia which enters the furnace for blending, and the other portion of the green hydrogen directly enters the furnace to participate in the ammonia / coal blending. The combustion characteristics of the fuel are improved by blending hydrogen and ammonia. Since ammonia combustion will have the problem of low adiabatic flame temperature, the green oxygen produced by the electrolysis of water using surplus electricity enters the furnace, which reduces the nitrogen content in the flue gas that does not participate in the reaction, increases the flame temperature and the concentration of free radicals, and enhances the combustion process of ammonia. By blending hydrogen and ammonia in an oxygen-rich environment, the flame combustion stability is effectively improved, a good flame temperature is maintained, and the problem of unstable combustion when the boiler is running at low load is solved.

[0030] For safe operation of the system, see Figure 2 The present invention also provides a purge system 12 and a venting system. The purge system 12 is respectively connected to the hydrogen main line 20, the hydrogen ignition branch system 21 and the oxygen pipeline system 22. The purge system 12 is respectively provided with manual ball valves and solenoid valves on the pipelines connected to the hydrogen main line 20, the pipelines connected to the hydrogen ignition branch system 21 and the pipelines connected to the oxygen pipeline system 22 for controlling the purge. The purge system is designed to replace the air in the pipeline with nitrogen in an emergency to reduce the possibility of hydrogen explosion; The release system includes a release pipeline, wherein: on the ammonia pipeline system 24 of the ammonia supply system, a release pipeline is connected at a position between the fourth shut-off valve 9-4 and the third flow regulating valve 11-3, and an eighth manual ball valve 8-7 and an ammonia release solenoid valve 10-2 are provided on the release pipeline; in the hydrogen supply system, a release pipeline is connected in parallel upstream and downstream of the first shut-off valve 9-1 on the hydrogen main pipeline system 20, one end of the release pipeline is connected to the inlet of the first shut-off valve 9-1, and the other end of the release pipeline is connected to the inlet of the second shut-off valve 9-2 and the inlet of the second manual ball valve 8-8, a hydrogen release solenoid valve 10-1 is provided on the release pipeline, and manual ball valves are provided at both ends of the release pipeline; in the oxygen supply system, a release pipeline is set between the third shut-off valve 9-3 and the second flow regulating valve 11-2 on the oxygen pipeline system 22, and a fourth manual ball valve 8-5 and an oxygen release solenoid valve 10-3 are provided on the release pipeline 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 release solenoid valve 10-1, the ammonia release solenoid valve 10-2 and the oxygen release solenoid valve 10-3 can be opened to effectively remove the hydrogen, ammonia or oxygen in the pipeline to ensure the safety of the system.

[0031] This system includes hydrogen, ammonia, and oxygen-enriched systems, all of which are equipped with safety measures in accordance with the "Technical Regulations for Explosion-proof Furnaces of Power Plant Boilers", such as a pressure regulating valve to ensure working pressure, a quick shut-off valve to ensure timely fuel shutdown in the event of an accident, a regulating valve to ensure matching of the gas volume required for each boiler load, a high-pressure fan to ensure the high-pressure air volume required for hydrogen combustion, and an automatic protection program connected to the DCS, etc., to ensure stable operation of the oxygen-enriched hydrogen-ammonia system.

[0032] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

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 are pulverized coal burners (14), and the two lower burners are micro hydrogen burners (15). The micro hydrogen burners (15) replace the original pulverized coal burners. Hydrogen is added to the micro hydrogen burners (15) during ignition and combustion assistance, and the micro hydrogen burners (15) are used as pulverized coal burners during normal operation. The combustion outlet of the micro hydrogen burners (15) is connected to the lower furnace of the boiler, and the hydrogen main 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 a lower secondary air nozzle, and the secondary air nozzle above is set as an ammonia-doped secondary air nozzle (19-1), and the secondary air nozzles above and below the highest 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 oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 1, characterized in that: The micro hydrogen burner (15) comprises a hydrogen ignition gun (15-1), a hydrogen main 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 hydrogen main gun (15-2) both extend to the combustion end of the first pulverized coal burner (15-3); the hydrogen main 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 fan (17), and the outlet of the high-pressure fan (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) comprises an ammonia nozzle (16) and an external secondary air nozzle (16-2), the ammonia nozzle (16) comprises an ammonia cyclone nozzle (16-1), the external secondary air nozzle (16-2) is connected to the secondary air pipeline 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); a 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); and a second manual ball valve (8-8), a solenoid valve (10-5) and an ignition solenoid valve are provided in sequence on the hydrogen ignition branch line system (21).

7. The oxygen-enriched hydrogen-ammonia system for power station boilers according to claim 1, characterized in that: The oxygen supply system comprises 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 comprises 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 arranged on the ammonia pipeline system (24) downstream of the ammonia storage tank (25); and a third differential pressure transmitter (5-3) is arranged on the ammonia pipeline system (24) at the third pressure regulating valve (6-3).

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

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 the flexible peak load regulation mode, the surplus electricity is used to electrolyze water through the water electrolysis system to produce green hydrogen and green oxygen, of which part of the hydrogen is provided to the hydrogen supply system and the other part is provided to the ammonia supply system for synthesizing ammonia. When the boiler is running at low load, the hydrogen in the hydrogen supply system is divided into two routes, which provide 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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