Ammonia-hydrogen-oxygen-water efficient low-nitrogen combustion power generation system and working method thereof

Abstract

The invention discloses an ammonia-hydrogen-oxygen-water efficient low-nitrogen combustion power generation system and a working method thereof. The system comprises a flexible fuel combustor, a liquid ammonia evaporator, an ammonia part catalytic cracking device, a device for preparing hydrogen and oxygen through water electrolysis, a water evaporation device and an electric energy distributor. Long-distance transported liquid ammonia is subjected to ammonia cracking through a liquid ammonia evaporator and an ammonia part catalytic cracking device to obtain ammonia-hydrogen-nitrogen mixed gas; the water electrolysis hydrogen production device is used for producing hydrogen and oxygen; ammonia-hydrogen-nitrogen mixed gas, hydrogen, oxygen, water vapor and air passing through an air compressor are introduced into the flexible fuel combustor, so that chemical energy is converted into heat work; the waste heat is supplied to the liquid ammonia evaporator, the ammonia part catalytic cracking device and the selective catalytic reduction device through the waste gas heat exchanger, so that the system efficiency is improved; the electricity storage and electric energy distributor distributes electric energy to each power consumption device, and stable electric energy is connected to a grid. Hydrogen, oxygen and the like are adopted for combustion enhancement of ammonia fuel, water vapor is adopted for solving the problem of nitrogen oxide emission, and efficient and stable low-nitrogen combustion power generation can be achieved.

Description

Technical Field

[0001] The present invention relates to a combustion power generation system, and particularly to an ammonia-hydrogen-oxygen-water high-efficiency and low-nitrogen combustion power generation system and its working method. Background Art

[0002] In the field of gas turbine power generation, the requirement for decarbonization is getting higher and higher. Due to the characteristics that ammonia fuel can be synthesized from hydrogen as a raw material, and has low storage and transportation pressure and temperature parameters, low cost, and is easy to store and transport, ammonia fuel gas turbines have become a new research hotspot.

[0003] However, on the one hand, the laminar flame speed of ammonia is low, the flame temperature is low, and the minimum ignition energy is high, making stable ammonia combustion very difficult. If the combustion organization is unreasonable, combustion instability is more likely to occur when encountering flow fluctuations. At this time, the combustion efficiency drops sharply, and the unburned ammonia emissions increase sharply. On the other hand, since ammonia fuel itself contains nitrogen elements, the fuel-type nitrogen oxides generated by combustion are very high, which cannot meet the requirements of emission regulations. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an ammonia-hydrogen-oxygen-water high-efficiency and low-nitrogen combustion power generation system and its working method. The technical route of selecting liquid ammonia vaporization coupled with on-line partial cracking to produce ammonia-hydrogen-nitrogen mixture gas, and electrolyzing water to produce hydrogen and oxygen to supply hydrogen and oxygen to strengthen ammonia combustion is adopted. A water evaporation device is selected to provide water vapor to be introduced into the burner to reduce the problems of local high temperature and high nitrogen oxide emissions caused by hydrogen blending. On the first hand, the stability problem of ammonia combustion is solved. On the second hand, the problem of high nitrogen oxide raw emissions after hydrogen blending is solved. On the third hand, water vapor blending is coupled with a selective catalytic reduction device and a catalytic oxidation device to solve the emissions of nitrogen oxides and unburned ammonia and hydrogen in the combustion exhaust gas of the system. On the fourth hand, an exhaust gas heat exchanger is used to supply the heat in the combustion exhaust gas to the liquid ammonia evaporator, the ammonia partial catalytic cracking device and the selective catalytic reduction device to improve the system efficiency. And, the present invention can also control the ammonia cracking volume fraction, the hydrogen and oxygen blending volume fraction, and the water vapor blending volume fraction through a central control unit, intelligently control stable combustion, nitrogen oxide and unburned ammonia and hydrogen emissions, achieve zero carbon emissions, and simultaneously reach the optimal operating efficiency state.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] An ammonia-hydrogen-oxygen-water high-efficiency and low-nitrogen combustion power generation system, comprising a flexible fuel burner, an electrolytic water hydrogen production device, a liquid ammonia evaporator, an ammonia partial catalytic cracking device and a water evaporation device.

[0007] The flexible fuel burner has two fuel inlets, one oxygen inlet, one air inlet, one water vapor inlet and one waste gas outlet. The two fuel inlets are respectively connected to an ammonia-hydrogen-nitrogen mixture and hydrogen; air is provided by an air compressor. The flexible fuel burner enhances the combustion of ammonia fuel by using hydrogen and oxygen, etc., and solves the nitrogen oxide emissions through water vapor, so as to achieve efficient, stable and low-nitrogen combustion power generation.

[0008] The liquid ammonia evaporator vaporizes the liquid ammonia transported over long distances stored in the liquid ammonia storage tank, and the obtained ammonia gas is input into the ammonia partial catalytic cracking device and cracked therein to obtain the ammonia-hydrogen-nitrogen mixture.

[0009] The electrolytic water hydrogen production device electrolyzes the liquid water passing through the water purification storage tank into hydrogen and oxygen. After separation by the hydrogen-oxygen separation device, the hydrogen is transported to the hydrogen storage tank and the oxygen is transported to the oxygen storage tank. The hydrogen and oxygen are respectively introduced into the flexible fuel burner to enhance the combustion of ammonia fuel;

[0010] The water evaporation device vaporizes the liquid water into water vapor and introduces it into the flexible fuel burner to inhibit nitrogen oxide emissions.

[0011] In one embodiment, the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes an exhaust gas heat exchanger and an electric heating device. The combustion waste heat is transported to the liquid ammonia evaporator, the ammonia partial catalytic cracking device and the selective catalytic reduction device through the exhaust gas heat exchanger to provide heat for the three, thereby improving the system thermal efficiency; the electric heating device heats the liquid ammonia evaporator, the ammonia partial catalytic cracking device and the selective catalytic reduction device to make up for the shortage of waste heat.

[0012] In one embodiment, the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes a selective catalytic reduction device and a catalytic oxidation device; nitrogen oxides are reduced by the selective catalytic reduction device, and unburned ammonia gas and hydrogen are oxidized by the catalytic oxidation device to realize a zero-emission system with only nitrogen and water in the tail gas.

[0013] In one embodiment, the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes: a power storage and power distributor; the power storage and power distributor distributes the electric energy input from the power grid when the system starts to drive each power-consuming component of the system; when the system generates electricity, it integrates and distributes the electric energy generated by the combusted gas pushing the turbine and the generator, and in addition to driving each power-consuming component of the system, it connects the electric energy to the grid; the power storage and power distributor also has a power storage function to provide electric energy for subsequent system startup.

[0014] In one embodiment, the high-efficiency, low-nitrogen combustion power generation system for ammonia-hydrogen-oxygen-water further includes a central control unit, which uniformly controls each fuel supply component, valve, sensor, each heat transfer, and detects the components and contents of emissions in the tail gas.

[0015] In one embodiment, control the fuel and air supply amounts of the flexible fuel burner, control the equivalence ratio to be 1.15, control the cracking rate of the ammonia partial catalytic cracking device to be 0-30%. When the cracking rate is 0, it is pure gaseous ammonia combustion. The cracking rate is the proportion of cracked ammonia in the total ammonia; control the hydrogen gas volume at the hydrogen inlet to account for 0-50% of the total fuel gas volume fraction. When the hydrogen gas volume fraction is 0, no hydrogen is introduced at the hydrogen inlet; control the oxygen gas amount at the oxygen inlet so that the volume fraction of oxygen in the total oxidant (the oxygen gas amount at the oxygen inlet + the air amount at the air inlet) is 21-60% (when it is 21%, there is only air and no oxygen is introduced at the oxygen inlet); control the volume fraction of water vapor in the total oxidant to be 0-30%. When the water vapor volume fraction is 0, no water vapor is added.

[0016] In one embodiment, the two fuel inlets of the flexible fuel burner are respectively an ammonia-hydrogen-nitrogen mixed gas inlet and a hydrogen inlet. A contraction section is arranged upstream of the ammonia-hydrogen-nitrogen mixed gas inlet, and a diffusion section is arranged downstream of the ammonia-hydrogen-nitrogen mixed gas inlet.

[0017] The contraction section is connected to a chamber, and the oxygen inlet, air inlet, and vapor inlet are all connected to this chamber.

[0018] The diffusion section is connected to a long straight pipe as a mixing section. The end of the mixing section is connected to the combustion chamber, and the hydrogen inlet is arranged downstream of the mixing section.

[0019] The working method of the ammonia-hydrogen-oxygen-water high-efficiency, low-nitrogen combustion power generation system of the present invention includes:

[0020] When the system starts, grid electric energy is transmitted to each power-consuming device to realize the operation of the device. Specifically, it can be transmitted by using a battery storage and power distributor. At this time, the cracking rate of the ammonia partial catalytic cracking device is relatively low due to the start-up temperature limitation, generally below 10%. At this time, the hydrogen and oxygen generated by the electrolytic water hydrogen production device are mixed and introduced into the flexible fuel burner to achieve a stable flame. The heat of heat-consuming devices such as the liquid ammonia evaporator, ammonia partial catalytic cracking device, and selective catalytic reduction device mainly comes from the electric heating device. Specifically, in this step, it can be controlled that the hydrogen and oxygen generated by the electrolytic water hydrogen production device are respectively introduced from the hydrogen inlet and oxygen inlet of the flexible fuel burner. The introduced hydrogen ratio is up to 50% of the total fuel volume fraction at most. After introducing oxygen, the oxygen ratio in the total oxidant is up to 60% of the volume fraction at most to achieve system ignition.

[0021] After operating stably for a period of time, gradually reduce the volume mixing ratio of hydrogen and oxygen generated by the electrolytic water hydrogen production device. Generally, reduce the volume fractions of hydrogen and oxygen introduced from the hydrogen inlet and oxygen inlet of the flexible fuel burner. The introduced hydrogen ratio is reduced to 20 - 30% of the total fuel volume fraction, and the introduced oxygen is reduced to 21 - 30% of the total oxidant volume fraction. At the same time, increase the cracking rate of the ammonia partial catalytic cracking device, which can generally be increased to 30%, and this can be achieved through the control of the central control unit. Through this part of the operation, while ensuring stable flame combustion, the electrolytic water ratio can be reduced, thereby reducing the system energy consumption and improving the system efficiency.

[0022] When the central control unit detects that the unburned ammonia in the tail gas exceeds the standard and exceeds the capacity of the catalytic oxidation device, the by-product oxygen from the electrolytic water hydrogen production in the oxygen storage tank is introduced into the flexible fuel burner to strengthen the oxygen addition to the ammonia combustion process, improve the ammonia combustion efficiency, and reduce the amount of unburned ammonia; in this step, control the amount of oxygen introduced from the oxygen inlet of the flexible fuel burner so that after introducing oxygen, the oxygen ratio in the total oxidant is 21 - 60% by volume fraction.

[0023] When the central control unit detects combustion instability phenomena such as temperature fluctuations and emission value fluctuations, according to the received unstable combustion signal, control the ammonia partial catalytic cracking device to increase the ammonia cracking rate, thereby increasing the hydrogen ratio in the ammonia - hydrogen - nitrogen mixed gas, and control the hydrogen and oxygen generated by the electrolytic water hydrogen production device to be introduced from the hydrogen inlet and oxygen inlet of the flexible fuel burner respectively. The introduced hydrogen ratio is up to 50% of the total fuel volume fraction at most. After introducing oxygen, the oxygen ratio in the total oxidant is up to 60% by volume fraction at most, to improve the combustion stability.

[0024] When the central control unit detects that the temperature and nitrogen oxides exceed the standard (generally referring to exceeding the treatment capacity of the selective catalytic reduction device), the water evaporation device vaporizes the liquid water into water vapor and introduces it into the flexible fuel burner to reduce the temperature of the combusted gas and reduce the nitrogen oxide emissions;

[0025] During stable operation, the system drives the generator to generate electricity through the turbine, and through the energy storage and power distribution device, part of the electric energy is stored, part is distributed to drive each power-consuming device, and the remaining electric energy is put into the grid.

[0026] In one embodiment, the thermal efficiency of the ammonia - hydrogen - oxygen - water high - efficiency, stable, and low - nitrogen combustion power generation system is 45 - 60%.

[0027] Compared with the prior art, in the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system of the present invention, liquid ammonia transported over long distances is cracked by a liquid ammonia evaporator and an ammonia partial catalytic cracking device to obtain an ammonia-hydrogen-nitrogen mixed gas, and a hydrogen production device by electrolyzing water produces hydrogen and oxygen, thereby solving the problem of stable ammonia combustion. A water evaporation device generates water vapor, and a selective catalytic reduction device and a catalytic oxidation device are used in combination to reduce the emissions of nitrogen oxides and unburned ammonia and hydrogen in the tail gas. Waste heat is supplied to the liquid ammonia evaporator, the ammonia partial catalytic cracking device and the selective catalytic reduction device through an exhaust gas heat exchanger to improve the system efficiency. The present invention can also control the volume fraction of ammonia cracking, the volume fraction of hydrogen and oxygen mixed, and the volume fraction of water vapor mixed through a central control unit, intelligently control stable combustion, the emissions of nitrogen oxides and unburned ammonia and hydrogen, achieve zero carbon emissions, and simultaneously reach the optimal operating efficiency state. The present invention can realize combustion enhancement of ammonia fuel by using hydrogen and oxygen, etc., and solve the problem of nitrogen oxide emissions by using water vapor, so as to achieve high-efficiency, stable and low-nitrogen combustion power generation. Brief Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the system of the present invention.

[0029] Figure 2 It is a schematic structural diagram of the flexible fuel burner in the present invention. Detailed Description of the Embodiment

[0030] The following will describe in detail the embodiments of the present invention with reference to the drawings and embodiments.

[0031] When using ammonia fuel in a gas turbine, there are problems such as poor combustion stability, low overall system efficiency, and high nitrogen oxide emissions. For this reason, the present invention provides an ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system, adopting the idea of "ammonia-hydrogen co-combustion" to regulate the ammonia flame with hydrogen. On the one hand, hydrogen is obtained by cracking ammonia, and on the other hand, hydrogen is obtained by electrolyzing water; adopting the idea of oxygen-enriched combustion, the by-product oxygen from hydrogen production by electrolyzing water is used to oxygenate and strengthen the ammonia flame to improve the combustion efficiency; adopting the idea of combustion, water vapor is mixed into the flame after oxygen addition and hydrogen addition to reduce the flame temperature and reduce nitrogen oxide emissions. Finally, high-efficiency, stable and low-nitrogen combustion power generation of the system is realized.

[0032] As Figure 1 shown, an ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system of the present invention mainly includes a flexible fuel burner 1, a hydrogen production device by electrolyzing water 7, a liquid ammonia evaporator 3, an ammonia partial catalytic cracking device 4 and a water evaporation device 11; the flexible fuel burner 1 can realize combustion enhancement of ammonia fuel by using hydrogen and oxygen, etc., and solve the problem of nitrogen oxide emissions by using water vapor, so as to achieve high-efficiency, stable and low-nitrogen combustion power generation.

[0033] As Figure 2The flexible fuel burner 1 of the present invention shown has two fuel inlets, an air inlet 30 (with four-way air intake), an oxygen inlet 29 (with four-way air intake), a water vapor inlet 31 and an exhaust gas outlet. The two fuel inlets are respectively an ammonia-hydrogen-nitrogen mixture inlet 26 (with four-way air intake) and a hydrogen inlet 23. Correspondingly, each fuel inlet (for those with four-way air intake, the pipelines are connected together) is respectively controlled by a flow valve to achieve different volume fraction conditions of ammonia-hydrogen-nitrogen mixture, hydrogen, oxygen and water vapor. Among them, the ammonia-hydrogen-nitrogen mixture is the main fuel supply, and other fuels are used for combustion support.

[0034] As Figure 2 As shown, the flexible fuel burner 1 of the present invention is connected to the combustion chamber 12. Hydrogen passes through the hydrogen inlet 23 and is introduced into the combustion chamber through the hydrogen injection holes 25. A swirler 24 is placed upstream of the combustion chamber 12 to form a swirling flow field in the combustion chamber 12. A contraction section 27 and an expansion section 28 are respectively arranged adjacent to the upstream and downstream of the ammonia-hydrogen-nitrogen mixture inlet 26 to achieve full mixing of water vapor, oxygen and air with the ammonia-hydrogen-nitrogen mixture introduced by the ammonia-hydrogen-nitrogen mixture inlet 26. A mixing section 22 is formed in the middle of the burner through a long straight pipe to further mix the premixed gas of ammonia-hydrogen-nitrogen mixture, water vapor, oxygen and air to form a fully developed turbulent flow.

[0035] The present invention provides the main ammonia-hydrogen-nitrogen mixture fuel through the liquid ammonia evaporator 3 and the ammonia partial catalytic cracking device 4. Based on the characteristics of easy storage and transportation of liquid ammonia, the liquid ammonia generated by the upstream fluctuating energy source is transported long-distance to the liquid ammonia storage tank 2 of the system equipment, vaporized into gaseous ammonia through the liquid ammonia evaporator 3, and converted into ammonia-hydrogen-nitrogen mixture through the ammonia partial catalytic cracking device, thereby increasing the laminar flame speed and flame temperature and reducing the minimum ignition energy compared with pure ammonia gas.

[0036] The electrolytic water hydrogen production device 7 of the present invention electrolyzes the liquid water passing through the water purification storage tank 6 into hydrogen and oxygen, and transports the hydrogen to the hydrogen storage tank 9 and the oxygen to the oxygen storage tank 10 respectively through the hydrogen-oxygen separation device 8. The hydrogen and oxygen are respectively introduced into the flexible fuel burner 1 to strengthen the combustion of ammonia fuel.

[0037] The water evaporation device 11 of the present invention vaporizes the liquid water into water vapor and introduces it into the flexible fuel burner 1 to reduce the flame temperature and nitrogen oxides after mixing with hydrogen and oxygen and solve the nitrogen oxide emissions.

[0038] In the embodiment of the present invention, with continued reference to Figure 1 , the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes an exhaust gas heat exchanger 16 to utilize the waste heat in the combusted exhaust gas.

[0039] Specifically, the waste gas heat exchanger 16 includes a heat inlet and three heat outlets. The heat inlet is connected to the combustion chamber 12 to extract the waste heat in the exhaust gas. The three heat outlets are respectively connected to the liquid ammonia evaporator 3, the ammonia partial catalytic cracking device 4, and the selective catalytic reduction device 14.

[0040] In an embodiment of the present invention, with continued reference to Figure 1 , the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes an electric heating device 17 to achieve the cold start of the devices that require heat.

[0041] Specifically, the electric heating device 17 includes an electric energy inlet and three heat outlets. The electric energy inlet is connected to the electricity storage and power distribution device 19. The three heat outlets are respectively connected to the liquid ammonia evaporator 3, the ammonia partial catalytic cracking device 4, and the selective catalytic reduction device 14.

[0042] Therefore, there are two ways for the heat source of the present invention, which are respectively: during cold start, the heat required by the liquid ammonia evaporator 3, the ammonia partial catalytic cracking device 4, and the selective catalytic reduction device 14 mainly comes from the electric energy input by the electricity storage and power distribution device 19 to the electric heating device 17, and the electric energy is converted into heat in the electric heating device 17. After startup, the waste gas heat exchange device 16 starts to work, and uses the waste heat of the exhaust gas from the combustion chamber 12 to heat the liquid ammonia evaporator 3, the ammonia partial catalytic cracking device 4, and the selective catalytic reduction device 14. At this time, the power of the electric heating device 17 decreases, and the generated heat is used to supplement the insufficient heat supplied by the waste gas heat exchange device 16.

[0043] In an embodiment of the present invention, with continued reference to Figure 1 , the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes a selective catalytic reduction device 14 and a catalytic oxidation device 15.

[0044] Specifically, the selective catalytic reduction device 14 converts the nitrogen oxides contained in the waste gas into nitrogen, and the catalytic oxidation device 15 oxidizes the unburned ammonia and hydrogen in the waste gas into nitrogen and water. The main components of the final emissions are nitrogen and water vapor, achieving pollution-free emissions.

[0045] In an embodiment of the present invention, with continued reference to Figure 1 , the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system further includes: an electricity storage and power distribution device 19;

[0046] Specifically, the electricity storage and power distribution device 19 distributes the electric energy input from the power grid during system startup to drive the power-consuming components of the system. During system power generation, it integrates and distributes the electric energy generated by the combustible gas pushing the turbine 13 and the generator 18 through the combustion chamber 12. In addition to driving the power-consuming components of the system, it also connects the electric energy to the grid. The electricity storage and power distribution device 19 also has an electricity storage function to provide electric energy for subsequent system startup.

[0047] In an embodiment of the present invention, with continued reference to Figure 1 , the ammonia-hydrogen-oxygen-water high-efficiency and low-nitrogen combustion power generation system further includes: a central control unit 20. The central control unit 20 is the overall control part, which can uniformly control each fuel supply component, valve, sensor, each heat transfer, and detect the composition and content of the emissions in the exhaust gas. In this embodiment, automatic control is added, that is, the central control unit 20. The central control unit 20 detects the composition and content of the exhaust gas, and then adjusts the supply amount of each fuel, the supply amount of water vapor, and the supply amount of air, so that the combustion power generation system is in a better performance and the emissions are at a lower level.

[0048] Exemplarily, the central control unit 20 controls the fuel and air supply amounts of the flexible fuel burner 1, controls the equivalence ratio to be 1.15, controls the cracking rate of the ammonia partial catalytic cracking device 4 to be 0-30%, and when the cracking rate is 0, it is pure gaseous ammonia combustion, and the cracking rate is the proportion of cracked ammonia in the total ammonia; controls the hydrogen gas volume fraction at the hydrogen inlet of the flexible fuel burner 1 to be 0-50% of the total fuel gas volume, and when the hydrogen gas volume fraction is 0, no hydrogen is introduced at the hydrogen inlet; controls the oxygen amount at the oxygen inlet of the flexible fuel burner 1 so that the volume fraction of oxygen in the total oxidant (the oxygen amount at the oxygen inlet + the air amount at the air inlet) is 21-60% (when it is 21%, there is only air and no oxygen is introduced at the oxygen inlet); controls the volume fraction of water vapor in the total oxidant of the flexible fuel burner 1 to be 0-30%, and when the water vapor volume fraction is 0, no water vapor is added.

[0049] A working method of the ammonia-hydrogen-oxygen-water high-efficiency and low-nitrogen combustion power generation system of the present invention includes:

[0050] When the system starts, the electricity storage and power distributor 19 delivers grid electricity to each power-consuming device to enable the operation of the devices. Liquid ammonia is pumped from the liquid ammonia storage tank 2 into the liquid ammonia evaporator 3, where it is heated and vaporized to form gaseous ammonia. The gaseous ammonia is introduced into the ammonia partial catalytic cracking device 4, where it undergoes partial cracking under high temperature and in the presence of a catalyst to produce an ammonia-hydrogen-nitrogen mixture, which is then introduced into the flexible fuel burner 1 and ignited in the combustion chamber 12 to form a flame. At this time, due to the start-up temperature limitation, the cracking rate of the ammonia partial catalytic cracking device 4 is relatively low, below 10%. At this time, the heat of the liquid ammonia evaporator 3, the ammonia partial catalytic cracking device 4, and the selective catalytic reduction device 14 mainly comes from the electric heating device 17. The electrolytic water hydrogen production device 7, driven by the electric energy input from the electricity storage and power distributor 19, electrolyzes the water supplied from the water purification storage tank 6 into hydrogen and oxygen, which enter the hydrogen storage tank 9 and the oxygen storage tank 10 respectively. The hydrogen and oxygen are further introduced into the flexible fuel burner 1 to improve the flame stability. At this time, it is controlled that the hydrogen and oxygen produced by the electrolytic water hydrogen production device 7 are introduced from the hydrogen inlet and the oxygen inlet of the flexible fuel burner 1 respectively, and the highest proportion of the introduced hydrogen is up to 50% of the volume fraction of the total fuel. After introducing oxygen, the highest proportion of oxygen in the total oxidant is up to 60% of the volume fraction, achieving a stable flame.

[0051] After stable operation for a period of time, the system temperature rises. The central control unit 20 gradually reduces the volume fractions of the hydrogen and oxygen produced by the electrolytic water hydrogen production device 7 entering the flexible fuel burner 1, and reduces the volume fractions of the hydrogen and oxygen introduced from the hydrogen inlet and the oxygen inlet of the flexible fuel burner 1. The proportion of the introduced hydrogen is reduced to 20 - 30% of the volume fraction of the total fuel, and the introduced oxygen is reduced to 21 - 30% of the volume fraction of the total oxidant. The cracking rate of the ammonia partial catalytic cracking device 4 is increased to 30%, ensuring stable flame combustion while reducing the electrolytic water ratio, thereby reducing the system energy consumption and improving the system efficiency.

[0052] When the central control unit 20 detects that the unburned ammonia in the tail gas exceeds the standard and exceeds the capacity of the catalytic oxidation device 15, the by-product oxygen from the electrolytic water hydrogen production in the oxygen storage tank 10 is introduced into the flexible fuel burner 1 to strengthen the oxygen addition to the ammonia combustion process. It is controlled that the oxygen is introduced from the oxygen inlet of the flexible fuel burner 1. After introducing oxygen, the volume fraction of oxygen in the total oxidant is 21 - 60%, improving the ammonia combustion efficiency and reducing the amount of unburned ammonia.

[0053] When the central control unit 20 detects combustion instability phenomena such as temperature fluctuations and emission value fluctuations, according to the received unstable combustion signal, it controls the ammonia partial catalytic cracking device 4 to increase the ammonia cracking rate, thereby increasing the hydrogen proportion in the ammonia-hydrogen-nitrogen mixed gas. It controls the hydrogen and oxygen generated by the electrolytic water hydrogen production device 7 to be introduced from the hydrogen inlet and oxygen inlet of the flexible fuel burner 1 respectively. The introduced hydrogen proportion is up to 50% of the total fuel by volume fraction. After introducing oxygen, the oxygen proportion in the total oxidant is up to 60% by volume fraction, improving combustion stability;

[0054] When the central control unit 20 detects that the temperature and nitrogen oxides exceed the processing capacity of the selective catalytic reduction device 14, the water evaporation device 11 vaporizes the liquid water into water vapor and introduces it into the flexible fuel burner 1 to reduce the temperature of the combusted gas and reduce nitrogen oxide emissions.

[0055] During stable operation, the system drives the generator 18 to generate electricity through the turbine 13. Through the energy storage and power distribution device 19, part of the electric energy is stored, part is distributed to drive each power-consuming device, and the remaining electric energy is grid-connected.

[0056] In summary, this system can gasify liquid ammonia and partially crack ammonia online through the ammonia catalytic cracking device to form an ammonia-hydrogen mixed gas, thereby improving combustion stability. The electrolytic water hydrogen production device provides hydrogen and oxygen for combustion, thereby strengthening ammonia combustion and improving combustion efficiency. The water evaporation device provides water vapor to reduce the temperature of the tail gas after combustion intensification and the original nitrogen oxide emissions. By coupling the energy storage and power distribution device and the electric heating device, the cold start of the system is realized. The waste gas heat exchanger is used to utilize the waste heat of the tail gas and improve the system efficiency. The selective catalytic reduction device is coupled with the catalytic oxidation device to solve the emissions of nitrogen oxides and unburned hydrogen and ammonia. The present invention can also select the operation mode through the central control unit and control the flow rate and cracking volume fraction of ammonia cracking, intelligently control stable combustion, the emissions of nitrogen oxides and unburned ammonia and hydrogen, achieve zero carbon emissions, and simultaneously reach a better operation state.

[0057] The above are only preferred embodiments of the present invention for the patent, but the protection scope of the present invention for the patent is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention for the patent, according to the technical solution of the present invention for the patent and its inventive concept, makes equivalent substitutions or changes, all belong to the protection scope of the present invention for the patent.

Claims

1. An ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system, characterized in that: It comprises a flexible fuel burner (1), a water electrolysis hydrogen production device (7), a liquid ammonia evaporator (3), an ammonia partial catalytic cracking device (4) and a water evaporation device (11); The flexible fuel burner (1) has two fuel inlets, an oxygen inlet (29), an air inlet (30), a water vapor inlet (31) and an exhaust gas outlet, wherein the two fuel inlets are connected to the ammonia-hydrogen-nitrogen mixed gas and the hydrogen respectively; The liquid ammonia evaporator (3) vaporizes the long-distance transported liquid ammonia stored in the liquid ammonia storage tank (2), and the obtained ammonia gas is input into the ammonia partial catalytic cracking device (4) and cracked therein to obtain the ammonia hydrogen nitrogen mixed gas; The water electrolysis hydrogen production device (7) electrolyzes the liquid water passing through the water purification tank (6) into hydrogen and oxygen, and after separation through the hydrogen and oxygen separation device (8), they are respectively introduced into the flexible fuel burner (1) to enhance the combustion of the ammonia fuel; The water evaporation device (11) vaporizes liquid water into water vapor, which is introduced into the flexible fuel burner (1) to suppress nitrogen oxide emissions.

2. The ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to claim 1 is characterized in that: The system also includes an exhaust gas heat exchanger (16) and an electric heating device (17). The waste heat from combustion is transported to the liquid ammonia evaporator (3), the ammonia partial catalytic cracking device (4) and the selective catalytic reduction device (14) through the exhaust gas heat exchanger (16), providing heat for the three, thereby improving the thermal efficiency of the system; the electric heating device (17) heats the liquid ammonia evaporator (3), the ammonia partial catalytic cracking device (4) and the selective catalytic reduction device (14), thereby supplementing the shortage of waste heat.

3. The ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to claim 2 is characterized in that: It also includes a selective catalytic reduction device (14) and a catalytic oxidation device (15); Nitrogen oxides are reduced by the selective catalytic reduction device (14), and unburned ammonia and hydrogen are oxidized by the catalytic oxidation device (15), thereby realizing a zero-emission system in which the tail gas contains only nitrogen and water.

4. The ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to claim 3 is characterized in that: Also includes: Power storage and energy distributor (19); The power storage and power distributor (19) distributes the electric energy input from the power grid when the system is started, and drives the various power-consuming components of the system; when the system is generating electricity, the combustion gas passes through the combustion chamber (12) to drive the turbine (13) and the generator (18) to integrate and distribute the electric energy, in addition to driving the various power-consuming components of the system, and connecting the electric energy to the grid; the power storage and power distributor (19) also has a power storage function, and provides electric energy for subsequent system startup.

5. The ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to claim 4 is characterized in that: Also includes: Central control unit (20); The central control unit (20) centrally controls various fuel supply components, valves, sensors, various heat transmissions, and detects the composition and content of emissions in the tail gas.

6. The ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to claim 1, characterized in that: The fuel and air supply amounts of the flexible fuel burner (1) are controlled to control the equivalent ratio to 1.15, and the cracking rate of the ammonia partial catalytic cracking device (4) is controlled to be 0-30%; the hydrogen amount at the hydrogen inlet is controlled to account for 0-50% of the total fuel gas volume fraction, and no hydrogen is introduced into the hydrogen inlet when the hydrogen volume fraction is 0; the oxygen amount at the oxygen inlet is controlled so that the volume fraction of oxygen in the total oxidant is 21-60%; and the volume fraction of water vapor in the total oxidant is controlled to be 0-30%.

7. The ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to any one of claims 1 to 6, characterized in that: The two fuel inlets of the flexible fuel burner (1) are respectively an ammonia-hydrogen-nitrogen mixed gas inlet (26) and a hydrogen inlet (23); a contraction section (27) is arranged immediately upstream of the ammonia-hydrogen-nitrogen mixed gas inlet (26); and an expansion section (28) is arranged immediately downstream of the ammonia-hydrogen-nitrogen mixed gas inlet (26); The contraction section (27) is connected to a chamber, and the oxygen inlet (29), the air inlet (30) and the steam inlet (31) are all connected to the chamber; The expansion section (28) is connected to a long straight pipe (22) as a mixing section, the end of the mixing section is connected to the combustion chamber (12), and the hydrogen inlet (23) is arranged downstream of the mixing section.

8. The working method of the ammonia-hydrogen-oxygen-water high-efficiency low-nitrogen combustion power generation system according to any one of claims 1 to 7, characterized in that: When the system is started, the grid electricity is transmitted to each power-consuming device to realize the operation of the device. At this time, the ammonia partial catalytic cracking device (4) is limited by the starting temperature, and the cracking rate is below 10%. The hydrogen and oxygen produced by the water electrolysis hydrogen production device (7) are mixed and enter the flexible fuel burner (1) to realize a stable flame. The heat of the heat-consuming device mainly comes from the electric heating device (17); After a period of stable operation, the volume mixing ratio of hydrogen and oxygen produced by the water electrolysis hydrogen production device (7) is reduced, the cracking ratio of the ammonia partial catalytic cracking device (4) is increased, and while ensuring stable flame combustion, the electrolysis water ratio is reduced to reduce system energy consumption; When the central control unit (20) detects that the unburned ammonia in the tail gas exceeds the standard and exceeds the capacity of the catalytic oxidation device (15), the by-product oxygen from the electrolysis of water to produce hydrogen in the oxygen storage tank (10) is introduced into the flexible fuel burner (1) at a volume fraction of 21-60% of the total oxidant to enhance the ammonia combustion process by oxygen addition; When the central control unit (20) detects that combustion instability has occurred, the ammonia partial catalytic cracking device (4) is controlled to increase the ammonia cracking rate so as to increase the hydrogen ratio in the ammonia-hydrogen-nitrogen mixed gas, and the hydrogen and oxygen generated by the water electrolysis hydrogen production device (7) are controlled to be introduced from the hydrogen inlet and the oxygen inlet of the flexible fuel burner (1) respectively, and the hydrogen ratio introduced is up to 50% by volume of the total fuel. After the oxygen is introduced, the oxygen ratio in the total oxidant is up to 60% by volume, thereby improving combustion stability; When the central control unit (20) detects that the temperature and nitrogen oxides exceed the standard, the water evaporation device (11) vaporizes the liquid water into water vapor and introduces it into the flexible fuel burner (1), thereby lowering the temperature of the combustion gas and reducing the emission of nitrogen oxides; During stable operation, the system drives the generator (18) to generate electricity through the turbine (13), stores part of the electric energy, distributes part of the electric energy to drive various power-consuming devices, and connects the remaining electric energy to the grid.

9. The working method according to claim 8, characterized in that: The thermal efficiency of the ammonia-hydrogen-oxygen-water high-efficiency stable low-nitrogen combustion power generation system is 45-60%.

10. The working method according to claim 8, characterized in that: When the system is started, the hydrogen and oxygen generated by the water electrolysis hydrogen production device (7) are controlled to be introduced from the hydrogen inlet and oxygen inlet of the flexible fuel burner (1) respectively, and the proportion of hydrogen introduced is up to 50% by volume of the total fuel. After the oxygen is introduced, the proportion of oxygen in the total oxidant is up to 60% by volume, so as to achieve system ignition; After a period of stable operation, the volume fractions of hydrogen and oxygen introduced from the hydrogen inlet and the oxygen inlet of the flexible fuel burner (1) are reduced, the ratio of introduced hydrogen is reduced to 20-30% of the volume fraction of the total fuel, and the ratio of introduced oxygen is reduced to 21-30% of the volume fraction of the total oxidant, thereby increasing the cracking rate of the ammonia partial catalytic cracking unit (4) to 30%.

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