Ammonia fuel system with carbon capture and method of processing thereof

Abstract

This invention provides an ammonia fuel system with carbon capture, comprising a main unit, a fuel tank, a capture tank, a denitrification tank, an ash tank, a carbon capture device, a neutralization tank, a spray tower, an inert gas storage tank, a supply pipe, a return pipe, and an exhaust pipe. The main unit is connected to the fuel tank via the supply and return pipes. A low-pressure pump is installed at the inlet end of the supply pipe. Along the direction of the main unit, the supply pipe sequentially includes a first heat exchanger, a high-pressure pump, and a first control valve group. Along the direction of the fuel tank, the return pipe sequentially includes a second control valve group, a pressure reducing valve, and a second heat exchanger. A safety valve is installed on the supply pipe. The main unit is equipped with an exhaust pipe connected to the denitrification tank. This invention enables controllable flow processing of ammonia vapor, suitable for various scenarios such as denitrification, ammonium bicarbonate generation, and boiler combustion, improving ammonia treatment efficiency and reducing environmental pollution.

Description

Technical Field

[0001] This invention discloses an ammonia fuel system with carbon capture and its treatment method, relating to the field of ammonia fuel tail gas treatment technology. Background Technology

[0002] In 2018, the International Maritime Organization adopted a preliminary strategy for reducing greenhouse gas emissions from ships, proposing the vision of achieving zero greenhouse gas emissions in the international maritime industry by the end of this century. The main engines of large ships have begun to be converted from traditional diesel and heavy oil to use various clean and low-carbon energy sources as fuel. NH3 fuel has stood out because it is carbon-free and has become an ideal fuel that meets the requirements of zero carbon emissions.

[0003] Ammonia liquefies at atmospheric pressure at -33°C, and enters the main engine at approximately 80 bar. Ammonia fuel storage typically employs three design methods: full-pressure, semi-cooled / semi-pressurized, or full-cooled. The semi-cooled / semi-pressurized and full-cooled designs operate at low temperatures (<5°C). While ammonia fuel is a viable alternative fuel solution, it is extremely toxic; levels above 30 ppm can cause harm to humans, and its vapor can form explosive mixtures with air. Therefore, the design of marine ammonia fuel supply systems must address the issues of ammonia capture and leakage collection and treatment. Common system designs generally present the following problems and drawbacks:

[0004] 1. Leaked or purged nitrogen-ammonia-air mixtures cannot be handled and are not easily liquefied and separated.

[0005] 2. If ammonia is absorbed by water mist to form an ammonia monohydrate solution, a large amount of space is required for storage.

[0006] 3. If water mist is used to absorb ammonia to form an ammonia monohydrate solution, the ammonia will evaporate when the temperature rises, and toxic gas will be formed again.

[0007] Ammonia fuel produces NOx after combustion in the main engine. According to existing technology, the ammonia vapor in the fuel tank can enter the flue pipe for NOx denitrification treatment. However, this only consumes a portion of the vapor, and the excess ammonia vapor cannot be treated in a timely manner. Summary of the Invention

[0008] The first objective of this invention is to provide an ammonia fuel system with carbon capture, which has the advantage of using water mist to absorb ammonia gas, forming an ammonia monohydrate solution, and then reacting it with carbon dioxide to generate ammonium bicarbonate crystals, greatly reducing the storage space required.

[0009] The second objective of this invention is to provide an ammonia treatment method that employs the aforementioned ammonia fuel system with carbon capture. Its advantages are: controllable flow rate processing of ammonia vaporization, and assistance from a carbon capture device, making it suitable for various application scenarios such as denitrification, generation of ammonium bicarbonate, and combustion in boilers.

[0010] To achieve the first objective mentioned above, the present invention is implemented through the following technical solution:

[0011] A carbon capture ammonia fuel system includes a main unit, a fuel tank, a capture tank, a denitrification tank, an ash tank, a carbon capture device, a neutralization tank, a spray tower, an inert gas storage tank, a supply pipe, a return pipe, a flue pipe, a gas phase pipe, a safety valve, a pressure reducing valve, a first ammonia pipe, a second ammonia pipe, and a third ammonia pipe. The main unit is connected to the fuel tank via the supply pipe and the return pipe. A low-pressure pump is installed at the inlet end of the supply pipe. Along the direction of the main unit, the supply pipe is sequentially equipped with a first heat exchanger, a high-pressure pump, and a first control valve assembly. Along the direction of the fuel tank, the return pipe is sequentially equipped with a second control valve assembly, a pressure reducing valve, and a second heat exchanger. A safety valve is installed on the supply pipe. The main unit is equipped with a flue pipe, which is connected to the denitrification tank. The liquid supply pipe and return pipe are both connected to the capture tank. A safety valve is provided between the liquid supply pipe and the capture tank. The capture tank is connected to the spray tower via a gas phase pipe. The spray tower is connected to the neutralization tank. The neutralization tank is connected to the carbon capture device. The neutralization tank is connected to the ash tank. The ash tank is connected to the denitrification tank via an ash conveying pipe. The first ammonia gas pipe passes through the neutralization tank and the ash tank in sequence and then connects to the second ammonia gas pipe. The second ammonia gas pipe is connected to the gas phase pipe. The second ammonia gas pipe is connected to the spray tower via the gas phase pipe. The second ammonia gas pipe is connected to the denitrification tank via a third ammonia gas pipe.

[0012] The present invention is further configured such that: a concentration detector is provided inside the spray tower, a first control valve is provided between the spray tower and the neutralization tank, and a second control valve is provided between the neutralization tank and the ash tank.

[0013] The present invention is further configured such that: the denitrification tank has a hexagonal prism structure, and a hexagonal prism baffle is provided inside the denitrification tank; after the ash conveying pipe enters the denitrification tank, several branches are symmetrically arranged, and nozzles are installed at the ends of the branches; the nozzles are arranged symmetrically around the hexagonal prism baffle; and a proportional valve is installed on the ash conveying pipe.

[0014] The present invention is further configured such that: an air intake pipe is provided at the end of the exhaust pipe, and a high-temperature fan, a third heat exchanger, and a compressor are sequentially provided on the air intake pipe, and an inert gas storage tank is connected to the end of the air intake pipe. An inert gas pipeline is provided on the inert gas storage tank, and the inert gas pipeline is simultaneously connected to an ash tank, an ash conveying pipe, and a liquid supply pipe. A second valve is provided at the connection between the inert gas pipeline and the ash tank, a first valve is provided at the connection between the inert gas pipeline and the ash conveying pipe, and a third valve is provided at the connection between the inert gas pipeline and the liquid supply pipe.

[0015] The present invention is further configured such that the first valve, the second valve, and the third valve are all one-way control valves.

[0016] The invention is further configured such that: a liquid ammonia pipe is provided at the bottom of the fuel tank, the liquid ammonia pipe is connected to a fourth heat exchanger, the fourth heat exchanger is connected to a third heat exchanger through a first pipe and a second pipe, the medium of the first pipe and the second pipe is an ethylene glycol solution; the ethylene glycol solution absorbs the heat of the inert gas entering through the intake pipe through the third heat exchanger, and after being heated, it enters the fourth heat exchanger to heat the liquid ammonia entering through the liquid ammonia pipe, so that the liquid ammonia vaporizes into ammonia vapor gas, which enters the pipe; through the above cycle, the cold energy of liquid ammonia and the heat energy of exhaust pipe are exchanged and utilized, and the ammonia vapor gas at the outlet of the fourth heat exchanger enters the neutralization tank through the pipe, so that the cold energy of the ammonia vapor gas is used to cool ammonium bicarbonate, so as to form ammonium bicarbonate crystals and maintain the low temperature in the ash tank so that the ammonium bicarbonate is stored stably and does not volatilize.

[0017] The present invention is further configured such that: the second ammonia pipe is connected to a boiler via a fourth ammonia pipe.

[0018] The invention also includes a control panel.

[0019] Through the above technical solution, the present invention allows liquid ammonia fuel to enter the main unit for combustion and work via a supply pipe, and the exhaust gas is discharged through a flue pipe into a denitrification tank. The NOx contained in the exhaust gas reacts with the incoming ammonium bicarbonate and ammonia in the denitrification tank to generate nitrogen, which is then discharged. Alternatively, either ammonium bicarbonate or ammonia can enter the denitrification tank to react with NOx and generate nitrogen, which is then discharged. This achieves the capture of NOx contained in the exhaust gas generated in the main unit in a more efficient, environmentally friendly, and economical way.

[0020] The second objective of this invention is achieved through the following technical solution: an ammonia treatment method, which employs the aforementioned ammonia nitrogen wastewater treatment system, comprising the following steps:

[0021] S1 ammonia fuel is stored in a fuel tank. The lower layer of the fuel tank contains liquid ammonia, and the upper layer contains ammonia vapor. The liquid ammonia passes through a low-pressure pump, a liquid supply pipe, a first heat exchanger, a high-pressure pump, and a first control valve group in sequence. After being regulated and pressurized, it enters the main engine for combustion and power generation.

[0022] S2 surplus fuel flows back into the fuel tank via the second control valve group, pressure reducing valve, second heat exchanger, and return pipe for reuse.

[0023] Liquid ammonia in the S3 pipeline enters the capture tank for vaporization; the vaporized ammonia gas enters the spray tower through the gas phase pipe and combines with water to form an ammonia hydrate solution.

[0024] Another method is: the ammonia vapor in the fuel tank enters the spray tower through the first ammonia pipe, the second ammonia pipe, and the gas phase pipe to generate a hydrated ammonia solution;

[0025] Once the S4 ammonia monohydrate reaches the preset concentration, it enters the neutralization tank. Simultaneously, carbon dioxide from the carbon capture device also enters the neutralization tank. The ammonia monohydrate solution reacts with the carbon dioxide to produce ammonium bicarbonate.

[0026] The reaction equation is: NH3·H2O + CO2 = NH4HCO3;

[0027] After dehydration, ammonium bicarbonate is stored in an ash container.

[0028] The low-temperature ammonia vapor enters the neutralization tank and ash tank sequentially through the first ammonia gas pipe for cooling, so as to form ammonium bicarbonate crystals and maintain the low temperature in the ash tank so that the ammonium bicarbonate can be stored stably without volatilization;

[0029] The S5 inert gas pipeline assists in blowing the ash tank through the second valve, and blows the ammonium bicarbonate in the tank into the denitrification tank through the ash conveying pipe.

[0030] Another method is: the ammonia vapor in the fuel tank enters the denitrification tank through the second ammonia pipe and the third ammonia pipe;

[0031] After the S6 liquid ammonia fuel enters the main unit through the supply pipe and performs work, the exhaust gas is discharged through the flue pipe and enters the denitrification tank. The NOx contained in the exhaust gas reacts with the incoming ammonium bicarbonate and ammonia in the denitrification tank to generate nitrogen gas, which is then discharged. Alternatively, according to the S5 method, either ammonium bicarbonate or ammonia gas enters the denitrification tank to react with NOx and generate nitrogen gas, which is then discharged.

[0032] After the S7 denitrification tank reacts, the discharged inert gas becomes nitrogen-based. Part of the inert gas is drawn in by a high-temperature fan through the intake pipe, cooled by the third heat exchanger, pressurized by the compressor, and then stored in the inert gas storage tank. The inert gas is distributed through pipelines. Opening the second valve allows the inert gas to enter the ash tank and blow ammonium bicarbonate into the ash conveying pipe. Opening the first valve allows the inert gas to enter the ash conveying pipe and blow ammonium bicarbonate into the denitrification tank. Opening the third valve allows the inert gas to enter the liquid supply pipe, the main unit, and the return pipe for inerting and purging.

[0033] The present invention is further configured such that: in step S6, when ammonium bicarbonate is stored in the ash tank, the ammonium bicarbonate enters the denitrification tank to remove NO. X When there is no ammonium bicarbonate in the ash tank, the ammonia vapor enters the denitrification tank sequentially through the first ammonia pipe, the second ammonia pipe, and the third ammonia pipe to react and remove NO. X .

[0034] One or more embodiments of the present invention can bring at least the following beneficial effects:

[0035] The beneficial effects of this invention are as follows:

[0036] 1. A capture system is provided that firstly absorbs ammonia gas using water mist to form an ammonia monohydrate solution, and then reacts with carbon dioxide to generate ammonium bicarbonate crystals, greatly reducing the storage space required.

[0037] 2. After dehydration, ammonium bicarbonate is in a solid state. It is then cooled by low-temperature ammonia vapor to maintain its stable state before being stored in an ash hopper for convenient use as needed.

[0038] 3. Ammonium bicarbonate and ammonia in the ash tank enter the denitrification tank to denitrify NOx in the flue gas pipe, purify the gas discharged from the main unit, and then collect and reuse it for harmless treatment.

[0039] 4. The main component of the discharged inert gas is nitrogen, which is recovered, compressed, and used for inerting and purging.

[0040] 5. The production of ammonium bicarbonate from ammonia is simple, has no explosive hazard, and is harmless to the human body, greatly reducing the harm caused by ammonia leaks on ships.

[0041] 6. The cold energy of ammonia vapor and the heat energy of flue gas are utilized in a closed loop to avoid heat waste. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a block diagram of an ammonia fuel system with carbon capture provided in an embodiment of the present invention.

[0044] The following are the labels shown in the diagram: 101. Main unit; 102. Fuel tank; 103. Low-pressure pump; 104. High-pressure pump; 105. First control valve assembly; 106. Second control valve assembly; 107. Capture tank; 108. Denitrification tank; 109. Ash tank; 1081. Hexagonal baffle; 1082. Nozzle; 111. First heat exchanger; 112. Second heat exchanger; 113. Third heat exchanger; 114. Fourth heat exchanger; 121. Carbon capture device; 122. Neutralization tank; 123. Spray tower; 124. Inert gas storage tank; 125. Compressor; 126. High-temperature fan; 27. Boiler; 201. Liquid supply unit. Pipe; 202, return pipe; 203, exhaust pipe; 204, gas phase pipe; 205, inert gas pipeline; 206, intake pipeline; 207, first pipeline; 208, second pipeline; 209, ash conveying pipe; 231, first control valve; 232, second control valve; 233, proportional valve; 241, first valve; 242, second valve; 243, third valve; 244, safety valve; 245, pressure reducing valve; 2011, liquid ammonia pipe; 2041, first ammonia pipe; 2042, second ammonia pipe; 2043, fourth ammonia pipe; 2044, third ammonia pipe; 301, concentration detector; 400, control panel. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0046] A carbon capture ammonia fuel system includes a main unit 101, a fuel tank 102, a capture tank 107, a denitrification tank 108, an ash tank 109, a carbon capture device 121, a neutralization tank 122, a spray tower 123, an inert gas storage tank 124, a liquid supply pipe 201, a liquid return pipe 202, a flue gas exhaust pipe 203, a gas phase pipe 204, a safety valve 244, a pressure reducing valve 245, a first ammonia gas pipe 2041, a second ammonia gas pipe 2042, and a third ammonia gas pipe 2044. The fuel tank 102 is semi-cooled and semi-pressurized or... The design is fully refrigerated, with a design temperature below 5℃. The main unit 101 is connected to the fuel tank 102 via a liquid supply pipe 201 and a liquid return pipe 202. A low-pressure pump 103 is installed at the inlet end of the liquid supply pipe 201. Along the direction of the main unit 101, the liquid supply pipe 201 sequentially includes a first heat exchanger 111, a high-pressure pump 104, and a first control valve group 105. Along the direction of the fuel tank 102, the liquid return pipe 202 sequentially includes a second control valve group 106, a pressure reducing valve 245, and a second heat exchanger 112. A safety valve 244 is installed on the liquid supply pipe 201. The main unit 101 is equipped with a flue pipe 203, which is connected to the denitrification tank 108. Both the liquid supply pipe 201 and the return pipe 202 are connected to the capture tank 107. A safety valve 244 is installed between the liquid supply pipe 201 and the capture tank 107. The capture tank 107 is connected to the spray tower 123 via a gas phase pipe 204. The spray tower 123 is connected to the neutralization tank 122. The neutralization tank 122 is connected to the carbon capture device 12. The neutralization tank 122 is connected to the ash tank 109, and the ash tank 109 is connected to the denitrification tank 108 through the ash conveying pipe 209. The first ammonia pipe 2041 passes through the neutralization tank 122 and the ash tank 109 in sequence and then connects to the second ammonia pipe 2042. The second ammonia pipe 2042 is connected to the gas phase pipe 204. The second ammonia pipe 2042 is connected to the spray tower 123 through the gas phase pipe 204. The second ammonia pipe 2042 is connected to the denitrification tank 108 through the third ammonia pipe 2044.

[0047] The spray tower 123 is equipped with a concentration detector 301. A first control valve 231 is provided between the spray tower 123 and the neutralization tank 122, and a second control valve 232 is provided between the neutralization tank 122 and the ash tank 109. Low-temperature ammonia vapor enters the neutralization tank 122 and the ash tank 109 sequentially through the first ammonia gas pipe 2041 to cool the media inside the tanks, thereby forming ammonium bicarbonate crystals and maintaining a low temperature inside the ash tank 109 to ensure stable storage and prevent volatilization of ammonium bicarbonate. When the concentration detector 301 controls the concentration of the ammonia monohydrate solution to be between 16% and 18%, the control valve 231 is opened to allow the ammonia monohydrate solution to enter the neutralization tank and react with carbon dioxide to generate ammonium bicarbonate. After further dehydration and cooling in the neutralization tank, ammonium bicarbonate crystals are formed. Opening the second control valve 232 allows the ammonium bicarbonate crystals to enter the ash tank 109.

[0048] The denitrification tank 108 has a hexagonal prism structure, and a hexagonal prism baffle 1081 is provided inside the denitrification tank 108. After the ash conveying pipe 209 enters the denitrification tank 108, it is symmetrically arranged with several branches. Each branch end is equipped with a nozzle 1082. The nozzles 1082 are symmetrically arranged around the hexagonal prism baffle 1081. A proportional valve 233 is installed on the ash conveying pipe 209. Ammonium bicarbonate enters through the ash conveying pipe 209 and is sprayed as a mist powder through the nozzle 1082. After the NOx-containing exhaust gas enters the denitrification tank 108 through the exhaust pipe 203, its vertical direction of travel is blocked by the hexagonal baffle 1081, changing the flow direction and slowing down the flow rate. This allows the sodium bicarbonate mist powder sprayed from the nozzle 1082 and the ammonia gas entering through the pipeline 2044 to mix and react fully, so that the NOx in the exhaust gas is converted into nitrogen gas. The ash conveying pipe 209 is equipped with a proportional valve 233, which adjusts the opening ratio to control the flow rate entering the denitrification tank 108, so as to match the NOx exhaust volume that changes due to the load of the main unit.

[0049] The exhaust pipe 203 is provided with an intake pipe 206 at its end. The intake pipe 206 is provided with a high-temperature fan 126, a third heat exchanger 113, and a compressor 125 in sequence. The intake pipe 206 is connected to an inert gas storage tank 124 at its end. The inert gas storage tank 124 is provided with an inert gas pipe 205. The inert gas pipe 205 is connected to the ash tank 109, the ash conveying pipe 209, and the liquid supply pipe 201. A second valve 242 is provided at the connection between the inert gas pipe 205 and the ash tank 109. A first valve 241 is provided at the connection between the inert gas pipe 205 and the ash conveying pipe 209. A third valve 243 is provided at the connection between the inert gas pipe 205 and the liquid supply pipe 201. After being processed by the denitrification tank 108, the discharged inert gas becomes nitrogen-based. Part of the inert gas is drawn in by the high-temperature fan 126 through the suction pipe 206, cooled by the third heat exchanger 113, pressurized by the compressor 125, and then stored in the inert gas storage tank 124. The inert gas is distributed through the inert gas pipe 205. The second valve 242 is opened, and the inert gas enters the ash tank 109 to blow ammonium bicarbonate into the ash conveying pipe 209. The first valve 241 is opened, and the inert gas enters the ash conveying pipe 209 to blow ammonium bicarbonate into the denitrification tank 108. The third valve 243 is opened, and the inert gas enters the liquid supply pipe 201, the main unit 101, and the return pipe 202 for inerting and purging.

[0050] The first valve 241, the second valve 242, and the third valve 243 are all one-way control valves. This structural design can effectively prevent the backflow of the purging medium.

[0051] The fuel tank 102 is equipped with a liquid ammonia pipe 2011 at its bottom. The liquid ammonia pipe 2011 is connected to a fourth heat exchanger 114. The fourth heat exchanger 114 is connected to a third heat exchanger 113 via a first pipe 207 and a second pipe 208. The medium in the first pipe 207 and the second pipe 208 is an ethylene glycol solution. The ethylene glycol solution absorbs the heat of the inert gas entering through the intake pipe 206 through the third heat exchanger 113. After being heated, it enters the fourth heat exchanger 114 to heat the liquid ammonia entering through the liquid ammonia pipe 2011, causing the liquid ammonia to vaporize into ammonia vapor gas. The ammonia vapor gas enters pipe 2041. Through the above cycle, the cold energy of the liquid ammonia is exchanged and utilized with the heat energy of the exhaust pipe. The ammonia vapor gas from the outlet of the fourth heat exchanger 114 also enters the neutralization tank 122 through pipe 2041, so that the cold energy of the ammonia vapor gas can be used to cool the ammonium bicarbonate.

[0052] The second ammonia pipe 2042 is connected to the boiler 127 via the fourth ammonia pipe 2043. When the ammonia evaporation rate in the fuel tank 102 is high, i.e., when there is a lot of evaporated gas causing the pressure inside the tank to rise, the ammonia gas can either enter the boiler 127 through the fourth ammonia pipe 2043 for combustion to produce steam, or enter the spray tower 123 through the second ammonia pipe 2042 and the gas phase pipe 204 to further produce ammonium bicarbonate.

[0053] It also includes a control panel 400. The control panel 400 is used for the control of all equipment and the on / off of valves, and is not limited to manual control, remote control, or automatic control.

[0054] An ammonia treatment method includes the following steps:

[0055] S1 Ammonia fuel is stored in fuel tank 102. The lower layer of fuel tank 102 is liquid ammonia and the upper layer is ammonia vapor. The liquid ammonia passes through low-pressure pump 103, liquid supply pipe 201, first heat exchanger 111, high-pressure pump 104, and first control valve group 105 in sequence for temperature and pressure adjustment before entering the main unit 101 for combustion and power generation.

[0056] The surplus fuel in S2 flows back into the fuel tank 102 via the second control valve group 106, pressure reducing valve 245, second heat exchanger 112, and return pipe 202 for reuse.

[0057] Liquid ammonia in pipeline S3 enters capture tank 107 for vaporization; the vaporized ammonia gas enters spray tower 123 through gas phase pipe 204 and combines with water to form ammonia hydrate solution.

[0058] Another method is: the ammonia vapor in the fuel tank 102 enters the spray tower 123 through the first ammonia pipe 2041, the second ammonia pipe 2042, and the gas phase pipe 204 to generate a hydrated ammonia solution;

[0059] After the S4 ammonia monohydrate reaches the preset concentration, it enters the neutralization tank 122. At the same time, carbon dioxide from the carbon capture device 121 also enters the neutralization tank 122. The ammonia monohydrate solution reacts with the carbon dioxide to produce ammonium bicarbonate.

[0060] The reaction equation is: NH3·H2O + CO2 = NH4HCO3;

[0061] After dehydration, ammonium bicarbonate is stored in an ash container.

[0062] Low-temperature ammonia vapor enters the neutralization tank 122 and the ash tank 109 sequentially through the first ammonia gas pipe 2041 for cooling, so as to form ammonium bicarbonate crystals and maintain the low temperature in the ash tank 109 so that the ammonium bicarbonate can be stored stably without volatilization.

[0063] S5 inert gas pipeline 205 provides purging to ash tank 109 through second valve 242, and blows ammonium bicarbonate in the tank into denitrification tank 108 through ash conveying pipe 209.

[0064] Another method is that the ammonia vapor in fuel tank 102 enters denitrification tank 108 through the second ammonia pipe 2042 and the third ammonia pipe 2044;

[0065] S6 liquid ammonia fuel enters the main unit through the liquid supply pipe 201 for combustion and power generation. The exhaust gas is discharged through the flue pipe 203 and enters the denitrification tank 108. The NOx contained in the exhaust gas reacts with the entering ammonium bicarbonate and ammonia in the denitrification tank to generate nitrogen gas, which is then discharged. Alternatively, according to the S5 method, either ammonium bicarbonate or ammonia gas enters the denitrification tank 108 to react with NOx and generate nitrogen gas, which is then discharged.

[0066] After being processed by the denitrification tank 108, the inert gas discharged from S7 becomes nitrogen-based. Part of the inert gas is drawn in by the high-temperature fan 126 through the suction pipe 206, cooled by the third heat exchanger 113, pressurized by the compressor 125, and then stored in the inert gas storage tank 124. The inert gas is distributed through the pipe 205. The second valve 242 is opened, and the inert gas enters the ash tank 109 to blow ammonium bicarbonate into the ash conveying pipe 209. The first valve 241 is opened, and the inert gas enters the ash conveying pipe 209 to blow ammonium bicarbonate into the denitrification tank 108. The third valve 243 is opened, and the inert gas enters the liquid supply pipe 201, the main unit 101, and the return pipe 202 for inerting and purging.

[0067] In step S6, when ammonium bicarbonate is stored in the ash tank, it enters the denitrification tank 108 to remove NO. X When there is no ammonium bicarbonate in the ash tank 109, the ammonia vapor enters the denitrification tank sequentially through the first ammonia pipe 2041, the second ammonia pipe 2042, and the third ammonia pipe 2044 to react and remove NO. X .

[0068] Example 1: Fuel tank 102 is designed as a semi-cooled, semi-pressurized system. Liquid ammonia is stored in the tank at -5°C and 8 bar, with a loading rate of 80%. The remaining 20% ​​is ammonia vapor. The liquid ammonia is pressurized to 80 bar by high-pressure pump 104 via supply pipe 201, heated to 35°C by first heat exchanger 111, and then enters the main unit 101 for combustion. After combustion, the exhaust gas enters the flue pipe, passes through denitrification tank 108, and generates inert gas, mainly composed of nitrogen, at a temperature of 100°C. This inert gas is drawn into intake pipe 206 by high-temperature fan 126 and undergoes heat exchange with water-glycol solution in third heat exchanger 113. The outlet inert gas temperature is 20°C, and the inlet temperature of water-glycol is 38°C. The outlet temperature is 45℃; water glycol circulates into the fourth heat exchanger 114 to exchange heat with liquid ammonia. The inlet temperature of water glycol is 45℃ and the outlet temperature is 38℃. The inlet temperature of liquid ammonia is -5℃ and the outlet temperature of ammonia vapor is 3℃. The inert gas from the outlet of the third heat exchanger 113 is pressurized by the compressor 125 and stored in the inert gas storage tank 124 at 10 bar, and then distributed for use through the inert gas pipeline 205. The surplus fuel in the main unit 101 is depressurized to 8 bar by the control valve group 106 and the pressure reducing valve 245, cooled to -5℃ by the second heat exchanger 112, and then returned to the fuel tank 102 through the return pipe 202 for reuse.

[0069] Example 2: The temperature of the ammonia vapor gas at the outlet of the fourth heat exchanger 114 is 3°C. The ammonia vapor gas enters the neutralization tank 122 to lower the temperature inside the tank to 18°C ​​so that ammonium bicarbonate crystallizes out. Then it enters the ash tank 109 to lower the temperature of the ammonium bicarbonate inside the tank to 12°C and maintain it in a stable state.

[0070] Example 3: The temperature of the ammonia vapor gas in the upper layer of fuel tank 102 is -3°C; the ammonia vapor gas enters neutralization tank 122 to lower the temperature inside the tank to 16°C to allow ammonium bicarbonate to crystallize and precipitate, and then enters ash tank 109 to lower the temperature of the ammonium bicarbonate inside the tank to 11°C, maintaining it in a stable state. In the several embodiments provided in this invention, it should be understood that the disclosed systems and methods can also be implemented in other ways. The system and method embodiments described above are merely illustrative.

[0071] It should be noted that, in this document, the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0072] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An ammonia fuel system with carbon capture, characterized in that, The system includes a main unit, a fuel tank, a capture tank, a denitrification tank, an ash tank, a carbon capture device, a neutralization tank, a spray tower, an inert gas storage tank, a liquid supply pipe, a liquid return pipe, a flue gas pipe, a gas phase pipe, a safety valve, a pressure reducing valve, a first ammonia pipe, a second ammonia pipe, and a third ammonia pipe. The main unit is connected to the fuel tank via the liquid supply pipe and the liquid return pipe. A low-pressure pump is installed at the inlet end of the liquid supply pipe. Along the direction of the main unit, the liquid supply pipe sequentially includes a first heat exchanger, a high-pressure pump, and a first control valve assembly. Along the direction of the fuel tank, the liquid return pipe sequentially includes a second control valve assembly, a pressure reducing valve, and a second heat exchanger. A safety valve is installed on the liquid supply pipe. The main unit has a flue gas pipe connected to the denitrification tank. Both the liquid supply pipe and the liquid return pipe are connected to the capture tank. The liquid supply pipe and the capture tank are connected... A safety valve is provided. The capture tank is connected to the spray tower via a gas phase pipe. The spray tower is connected to the neutralization tank. The neutralization tank is connected to the carbon capture device. The neutralization tank is connected to the ash tank. The ash tank is connected to the denitrification tank via an ash conveying pipe. The first ammonia pipe is used to receive ammonia vapor from the fuel tank. The first ammonia pipe passes through the neutralization tank and the ash tank in sequence and then connects to the second ammonia pipe. The second ammonia pipe is connected to the gas phase pipe. The second ammonia pipe is connected to the spray tower via the gas phase pipe. The second ammonia pipe is connected to the denitrification tank via a third ammonia pipe. The end of the exhaust pipe is provided with an intake pipe. The end of the intake pipe is connected to the inert gas storage tank. The inert gas storage tank is provided with an inert gas pipe. The inert gas pipe is simultaneously connected to the ash tank, the ash conveying pipe, and the liquid supply pipe.

2. The ammonia fuel system with carbon capture according to claim 1, characterized in that, The spray tower is equipped with a concentration detector, which controls the concentration of the ammonia monohydrate solution within a preset range. A first control valve is provided between the spray tower and the neutralization tank, and a second control valve is provided between the neutralization tank and the ash tank.

3. The ammonia fuel system with carbon capture according to claim 1, characterized in that, The denitrification tank has a hexagonal prism structure and is equipped with a hexagonal prism baffle inside. After the ash conveying pipe enters the denitrification tank, it has several branches symmetrically arranged. Each branch end is equipped with a nozzle. The nozzles are arranged symmetrically around the hexagonal prism baffle. The ash conveying pipe is equipped with a proportional valve.

4. The ammonia fuel system with carbon capture according to claim 1, characterized in that, The exhaust pipe is equipped with an intake pipe at its end. A high-temperature fan, a third heat exchanger, and a compressor are sequentially installed on the intake pipe. The end of the intake pipe is connected to an inert gas storage tank. An inert gas pipeline is installed on the inert gas storage tank. The inert gas pipeline is connected to an ash tank, an ash conveying pipe, and a liquid supply pipe. A second valve is installed at the connection between the inert gas pipeline and the ash tank. A first valve is installed at the connection between the inert gas pipeline and the ash conveying pipe. A third valve is installed at the connection between the inert gas pipeline and the liquid supply pipe.

5. An ammonia fuel system with carbon capture according to claim 4, characterized in that, The first valve, the second valve, and the third valve are all one-way control valves.

6. An ammonia fuel system with carbon capture according to claim 1, characterized in that, The bottom of the fuel tank is equipped with a liquid ammonia pipe, which is connected to a fourth heat exchanger. The fourth heat exchanger is connected to a third heat exchanger through a first pipe and a second pipe. The medium in the first pipe and the second pipe is a water-glycol solution. The aqueous glycol solution absorbs heat from the inert gas entering through the suction pipe via the third heat exchanger. After being heated, it enters the fourth heat exchanger, where it heats the liquid ammonia entering through the liquid ammonia pipe, causing the liquid ammonia to vaporize into ammonia vapor gas. The ammonia vapor gas then enters the first ammonia pipe, thus realizing the exchange and utilization of the cold energy of the liquid ammonia with the heat energy of the exhaust pipe. This also allows the ammonia vapor gas from the outlet of the fourth heat exchanger to enter the neutralization tank through the first ammonia pipe. The low-temperature ammonia vapor gas then enters the neutralization tank and the ash tank sequentially through the first ammonia pipe to cool the media inside the tanks, forming ammonium bicarbonate crystals and maintaining the low temperature inside the ash tank to ensure stable storage of ammonium bicarbonate without volatilization.

7. An ammonia fuel system with carbon capture according to claim 1, characterized in that, The second ammonia pipe is connected to the boiler via the fourth ammonia pipe.

8. An ammonia fuel system with carbon capture according to any one of claims 1-7, characterized in that: It also includes the control panel.

9. A method for processing an ammonia fuel system with carbon capture, implemented using the ammonia fuel system with carbon capture as described in claim 8, characterized in that, Includes the following steps: S1 ammonia fuel is stored in a fuel tank. The lower layer of the fuel tank contains liquid ammonia, and the upper layer contains ammonia vapor. The liquid ammonia passes through a low-pressure pump, a liquid supply pipe, a first heat exchanger, a high-pressure pump, and a first control valve group in sequence. After being regulated and pressurized, it enters the main engine for combustion and power generation. S2 surplus fuel flows back into the fuel tank via the second control valve group, pressure reducing valve, second heat exchanger, and return pipe for reuse. Liquid ammonia in the S3 pipeline enters the capture tank for vaporization; the vaporized ammonia gas enters the spray tower through the gas phase pipe and combines with water to form an ammonia hydrate solution. Another method is: the ammonia vapor in the fuel tank enters the spray tower through the first ammonia pipe, the second ammonia pipe, and the gas phase pipe to generate a hydrated ammonia solution; Once the S4 ammonia monohydrate reaches the preset concentration, it enters the neutralization tank. Simultaneously, carbon dioxide from the carbon capture device also enters the neutralization tank. The ammonia monohydrate solution reacts with the carbon dioxide to produce ammonium bicarbonate. The reaction equation is: NH3·H2O + CO2 = NH4HCO3; After dehydration, ammonium bicarbonate is stored in an ash container. The low-temperature ammonia vapor enters the neutralization tank and ash tank sequentially through the first ammonia gas pipe for cooling, so as to form ammonium bicarbonate crystals and maintain the low temperature in the ash tank so that the ammonium bicarbonate can be stored stably without volatilization; The S5 inert gas pipeline assists in blowing the ash tank through the second valve, and blows the ammonium bicarbonate in the tank into the denitrification tank through the ash conveying pipe. Another method is: the ammonia vapor in the fuel tank enters the denitrification tank through the second ammonia pipe and the third ammonia pipe; S6 liquid ammonia fuel enters the main engine for combustion via the supply pipe, and the exhaust gas is discharged through the flue pipe into the denitrification tank; the exhaust gas contains NO. x The nitrogen gas reacts with the incoming ammonium bicarbonate and ammonia gas in the denitrification tank, and is then discharged after generating nitrogen gas; another method is as described in S5, where either ammonium bicarbonate or ammonia gas enters the denitrification tank and reacts with NO. x The reaction proceeds, producing nitrogen gas which is then released. After the S7 is processed by the denitrification tank, the discharged inert gas becomes nitrogen as the main component. Part of the inert gas is drawn in by the high-temperature fan through the intake pipe, cooled by the third heat exchanger, pressurized by the compressor, and then stored in the inert gas storage tank. The inert gas is distributed through the pipeline. The second valve is opened and the inert gas enters the ash tank to blow ammonium bicarbonate into the ash conveying pipe. Open the first valve, and inert gas enters the ash conveying pipe to blow ammonium bicarbonate into the denitrification tank; open the third valve, and inert gas enters the liquid supply pipe, main unit, and return pipe for inerting and purging.

10. A method for processing an ammonia fuel system with carbon capture according to claim 9, characterized in that... In step S6, when ammonium bicarbonate is stored in the ash tank, it enters the denitrification tank to remove NO. x When there is no ammonium bicarbonate in the ash tank, the ammonia vapor enters the denitrification tank sequentially through the first ammonia pipe, the second ammonia pipe, and the third ammonia pipe to react and remove NO. x .

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