Ship ammonia fuel supply and exhaust gas treatment system

Abstract

This invention provides a marine ammonia fuel supply and exhaust gas treatment system, comprising an ammonia fuel supply unit, an exhaust gas treatment unit, an ammonia fuel engine using liquid ammonia as fuel, fuel oil equipment using oil as fuel, and an SCR denitrification device. The ammonia fuel supply unit includes a liquid ammonia storage tank, a low-pressure supply pump, a buffer tank, a high-pressure pump, and a heating device. The exhaust gas treatment unit includes a freshwater supply device, an ammonia water tank, an ammonia water pump, an absorption tower, a discharge pipeline, a pretreatment tower, and a seawater supply device. This marine ammonia fuel supply and exhaust gas treatment system can simultaneously treat BOG gas in the liquid ammonia storage tank and the exhaust gas from the ammonia fuel engine and fuel oil equipment. It not only achieves near-zero CO2 emissions from the exhaust gas but also enables the recovery and reuse of BOG gas and CO2, improving economic efficiency.

Description

Technical Field

[0001] This invention relates to the field of marine fuel supply technology, and in particular to a marine ammonia fuel supply and exhaust gas treatment system. Background Technology

[0002] With increasing awareness of marine environmental protection, requirements for ship emissions are becoming increasingly stringent. The International Maritime Organization (IMO) has issued a series of pollution prevention conventions concerning ship emissions, establishing detailed emission standards for pollutants such as nitrogen oxides (NOx) and sulfur oxides (SOx). According to Annex VI of MARPOL 73 / 78 issued by the IMO, after 2020, for marine low-speed engines, the emission limits for NOx in non-controlled emission areas are 14.4 g / kW·h, and for SOx are 0.5% m / m; in ECA areas (Emission Restricted Areas), the emission limits for NOx are 3.4 g / kW·h, and for SOx are 0.1% m / m. Regarding carbon oxide emissions, the IMO has also established the latest EEDI standard, which sets higher requirements for ship design, ship equipment, and the application of new energy technologies. Conventional oil-fired ships emit large amounts of carbon dioxide, sulfur oxides, and nitrogen oxides in their exhaust, causing severe greenhouse gas effects, photochemical smog, acid rain, and other pollution that endangers global climate and human health. Developing a clean fuel for ships has become a pressing issue for ship equipment manufacturers. After experimenting with clean energy sources such as natural gas and methanol, attention has turned to ammonia fuel. Ammonia fuel contains only nitrogen and hydrogen atoms in its molecular formula, and under ideal conditions, it burns to produce nitrogen and water, eliminating carbon and sulfur emissions. It is a clean energy source with significant development potential.

[0003] However, in practical applications, ammonia fuel still produces nitrogen oxide emissions (i.e., nitrogen oxides are present in the exhaust gas of ammonia-fueled engines). For dual-fuel ships using ammonia as fuel, there are problems such as difficulty in handling BOG (bottlenecks from ammonia fuel are supplied in the form of liquid ammonia, and some of the liquid ammonia in the storage tank will evaporate to produce ammonia gas. This ammonia gas is generally processed into liquid ammonia by reliquefaction equipment and then returned to the storage tank; however, the equipment cost of reliquefaction equipment is relatively high). In addition, the boilers and generators on board still rely on fuel oil as a power source, which poses carbon emission problems. Summary of the Invention

[0004] The purpose of this invention is to provide a ship ammonia fuel supply and exhaust gas treatment system that can simultaneously treat BOG gas in liquid ammonia storage tanks and exhaust gas from ammonia fuel main engines and fuel equipment. This system not only achieves near-zero CO2 emissions from exhaust gas, but also enables the recovery and reuse of BOG gas and CO2, thereby improving economic efficiency.

[0005] This invention provides a ship ammonia fuel supply and exhaust gas treatment system, including an ammonia fuel supply unit, an exhaust gas treatment unit, an ammonia fuel main engine using liquid ammonia as fuel, fuel oil equipment using fuel oil as fuel, and an SCR denitrification device; the ammonia fuel supply unit includes a liquid ammonia storage tank, a low-pressure supply pump, a buffer tank, a high-pressure pump, and a heating device; the exhaust gas treatment unit includes a freshwater supply device, an ammonia water tank, an ammonia water pump, an absorption tower, a discharge pipeline, a pretreatment tower, and a seawater supply device;

[0006] The inlet of the low-pressure supply pump is connected to the liquid ammonia storage tank, the outlet of the low-pressure supply pump is connected to the inlet of the buffer tank, the outlet of the buffer tank is connected to the inlet of the high-pressure pump, the outlet of the high-pressure pump is connected to the inlet of the heating device, and the outlet of the heating device is connected to the ammonia fuel main unit.

[0007] The exhaust outlet of the ammonia fuel main unit and the exhaust outlet of the fuel oil equipment are both connected to the inlet of the SCR denitrification device, and the outlet of the SCR denitrification device is connected to the top inlet of the pretreatment tower; a first spray device is provided at the top of the pretreatment tower, and the seawater supply device is connected to the first spray device; the bottom outlet of the pretreatment tower is connected to the bottom inlet of the absorption tower.

[0008] The ammonia outlet of the liquid ammonia storage tank and the fresh water supply device are both connected to the inlet of the ammonia tank, and the outlet of the ammonia tank is connected to the inlet of the ammonia pump; a second spray device is provided at the top of the absorption tower, the outlet of the ammonia pump is connected to the second spray device, and the drain pipe is connected to the bottom outlet of the absorption tower.

[0009] Furthermore, the ammonia fuel supply unit also includes a liquid ammonia supply pipeline, one end of which is connected to the pipeline between the outlet of the low-pressure supply pump and the inlet of the buffer tank, and the other end of which is connected to the inlet of the ammonia water tank.

[0010] Furthermore, a BOG supply regulating valve is installed on the pipeline between the ammonia outlet of the liquid ammonia storage tank and the inlet of the ammonia water tank, a liquid ammonia supply regulating valve is installed on the liquid ammonia supply pipeline, and a freshwater regulating valve is installed on the pipeline between the freshwater supply device and the inlet of the ammonia water tank; a pressure sensor is installed on the liquid ammonia storage tank, and a first level gauge and a first pH meter are installed on the ammonia water tank; the ship ammonia fuel supply and exhaust gas treatment system also includes a control module, which is electrically connected to the BOG supply regulating valve, the liquid ammonia supply regulating valve, the freshwater regulating valve, the first level gauge, the first pH meter, and the pressure sensor, respectively.

[0011] Furthermore, the ammonia fuel supply unit also includes a liquid ammonia reflux pipeline, one end of which is connected to the pipeline between the outlet of the low-pressure supply pump and the inlet of the buffer tank, and the other end of which is connected to the liquid ammonia storage tank; one end of the liquid ammonia supply pipeline is connected to the liquid ammonia reflux pipeline, and the other end of which is connected to the pipeline between the ammonia outlet of the liquid ammonia storage tank and the inlet of the ammonia water tank.

[0012] Furthermore, a packing material is provided in the middle of the absorption tower, and the packing material is located between the second spray device and the bottom inlet of the absorption tower.

[0013] Furthermore, a temperature sensor is installed on the pipeline between the bottom outlet of the pretreatment tower and the bottom inlet of the absorption tower; the ship ammonia fuel supply and exhaust gas treatment system also includes a control module, which is electrically connected to the temperature sensor and the seawater supply device respectively.

[0014] Furthermore, the exhaust gas treatment unit also includes a water tank, which is connected to the top outlet of the absorption tower.

[0015] Furthermore, the exhaust gas treatment unit also includes a post-processor, and the drain pipe is connected to the post-processor, which is used to process the ammonium bicarbonate solution into solid ammonium bicarbonate.

[0016] Furthermore, the fuel-fired equipment includes a fuel-fired boiler and a fuel-fired generator, and the exhaust outlets of the fuel-fired boiler and the fuel-fired generator are both connected to the inlet of the SCR denitrification device.

[0017] Furthermore, a second pH meter is installed on the absorption tower, which is used to detect the pH value of the ammonium bicarbonate solution generated in the reaction within the absorption tower. The ship's ammonia fuel supply and exhaust gas treatment system also includes a control module, which is electrically connected to the second pH meter, the ammonia pump, and the fuel equipment. The control module is used to control the flow rate of the ammonia pump based on the pH value measured by the second pH meter and the current total power of the fuel equipment. The set flow rate of the ammonia pump meets the following conditions:

[0018] F 设定 = k*P / α; where, F 设定 Here, P is the set flow rate of the ammonia pump, P is the current total power of the fuel system, k is the correlation coefficient between the flow rate of the ammonia pump and the power of the fuel system, and α is the fine-tuning coefficient related to the pH value; where α = pH 测量值 / PH 饱和碳酸氢铵溶液 PH 测量值 The pH value measured by the second pH meter. 饱和碳酸氢铵溶液This represents the pH value of the saturated ammonium bicarbonate solution at the current temperature.

[0019] The present invention provides a marine ammonia fuel supply and exhaust gas treatment system. The ammonia fuel engine uses liquid ammonia as fuel, and its exhaust gas contains nitrogen oxides. The fuel oil equipment uses fuel oil as fuel, and its exhaust gas contains nitrogen oxides, sulfur oxides, and carbon dioxide. After nitrogen oxides are removed from the exhaust gas of the ammonia fuel engine and the fuel oil equipment, the exhaust gas is cooled by seawater spraying in the pretreatment tower to remove sulfur oxides. The remaining exhaust gas enters the absorption tower. BOG in the liquid ammonia storage tank enters the ammonia water tank and mixes with fresh water to form ammonia water. The ammonia water is pumped to the absorption tower and sprayed out by the second spray device. The sprayed ammonia water reacts countercurrently with carbon dioxide in the exhaust gas to generate ammonium bicarbonate solution. The ammonium bicarbonate solution can be discharged outside the absorption tower through the drain pipe. This system uses BOG gas from a liquid ammonia storage tank as a CO2 absorbent to absorb CO2 emitted by fuel equipment. It not only achieves near-zero CO2 emissions for the entire system, but also consumes and reuses the BOG gas in the liquid ammonia storage tank to maintain stable pressure in the tank. This solves the problem of difficult-to-handle BOG from ammonia fuel, while also generating commercially valuable chemical fertilizers. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the ship ammonia fuel supply and exhaust gas treatment system in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the control logic of the control module in an embodiment of the present invention. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0024] The directional terms such as "up," "down," "left," "right," "front," "back," "top," and "bottom" (if present) used in the specification and claims of this invention are defined by the position of the structures in the drawings and the relative positions of the structures, and are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of directional terms should not limit the scope of protection claimed in this application.

[0025] like Figure 1As shown, the ship ammonia fuel supply and exhaust gas treatment system provided in this embodiment of the invention includes an ammonia fuel supply unit 1, an exhaust gas treatment unit 2, an ammonia fuel engine 3 using liquid ammonia as fuel, a fuel oil equipment 4 using fuel oil (specifically, an equipment using low-sulfur fuel oil as fuel), and an SCR denitrification device 5. The ammonia fuel supply unit 1 includes a liquid ammonia storage tank 11, a low-pressure supply pump 12, a buffer tank 13, a high-pressure pump 14, and a heating device 15. The exhaust gas treatment unit 2 includes a freshwater supply device 21, an ammonia water tank 22, an ammonia water pump 23, an absorption tower 24, a discharge pipeline 25, a pretreatment tower 26, and a seawater supply device 27.

[0026] Liquid ammonia storage tank 11 is used to store liquid ammonia. The inlet of low-pressure supply pump 12 is connected to liquid ammonia storage tank 11, the outlet of low-pressure supply pump 12 is connected to the inlet of buffer tank 13, the outlet of buffer tank 13 is connected to the inlet of high-pressure pump 14, the outlet of high-pressure pump 14 is connected to the inlet of heating device 15, and the outlet of heating device 15 is connected to ammonia fuel main unit 3. Liquid ammonia in liquid ammonia storage tank 11 is pumped to buffer tank 13 by low-pressure supply pump 12, and then pressurized and temperature-regulated by high-pressure pump 14 and heating device 15 before being supplied to ammonia fuel main unit 3 for combustion.

[0027] The exhaust outlets of the ammonia fuel main unit 3 and the fuel oil equipment 4 are both connected to the inlet of the SCR denitrification device 5. The outlet of the SCR denitrification device 5 is connected to the top inlet of the pretreatment tower 26. A first spray device 261 is provided at the top of the pretreatment tower 26. The outlet of the seawater supply device 27 is connected to the first spray device 261 (the first spray device 261 may include a spray pipeline and nozzles installed on the spray pipeline). The bottom outlet of the pretreatment tower 26 is connected to the bottom inlet of the absorption tower 24. The exhaust gas from the ammonia fuel main unit 3 contains nitrogen oxides, and the exhaust gas from the fuel equipment 4 contains nitrogen oxides, sulfur oxides, and carbon dioxide. The exhaust gas from the ammonia fuel main unit 3 and the fuel equipment 4 enter the SCR denitrification unit 5 to remove nitrogen oxides, and then the exhaust gas enters the pretreatment tower 26. Seawater from the seawater supply unit 27 is sprayed out of the pretreatment tower 26 through the first spray device 261. The sprayed seawater and the exhaust gas are mixed and reacted in the pretreatment tower 26, which can cool the exhaust gas (the exhaust gas temperature should not be too high; if the exhaust gas temperature is too high, the ammonia in the ammonia water will escape, which is not conducive to the reaction between the ammonia water and the carbon dioxide in the exhaust gas) and remove sulfur oxides from the exhaust gas. The exhaust gas after seawater treatment enters the absorption tower 24 through the bottom inlet of the absorption tower 24.

[0028] The ammonia outlet (i.e., BOG outlet) of the liquid ammonia storage tank 11 and the outlet of the fresh water supply device 21 are both connected to the inlet of the ammonia water tank 22. The outlet of the ammonia water tank 22 is connected to the inlet of the ammonia water pump 23. A second spray device 241 is provided at the top of the absorption tower 24 (the second spray device 241 may include a spray pipeline and nozzles installed on the spray pipeline, etc.). The outlet of the ammonia water pump 23 is connected to the second spray device 241. The drain pipeline 25 is connected to the bottom outlet of the absorption tower 24. The ammonia gas (BOG) generated by the evaporation of liquid ammonia in the liquid ammonia storage tank 11 and the fresh water supplied by the fresh water supply device 21 enter the ammonia water tank 22 and mix to form ammonia water of a certain concentration. The ammonia water in the ammonia water tank 22 is transported to the absorption tower 24 by the ammonia water pump 23 and sprayed from top to bottom by the second spray device 241. The sprayed ammonia water reacts with the carbon dioxide in the tail gas in a countercurrent manner to generate ammonium bicarbonate solution. The ammonium bicarbonate solution can be discharged to the outside of the absorption tower 24 through the drain pipe 25.

[0029] The ship ammonia fuel supply and exhaust gas treatment system provided in this embodiment of the invention uses liquid ammonia as fuel in the ammonia fuel main engine 3, and its exhaust gas contains nitrogen oxides; the fuel oil equipment 4 uses fuel oil as fuel, and its exhaust gas contains nitrogen oxides, sulfur oxides and carbon dioxide and other gases; after nitrogen oxides are removed from the exhaust gas of the ammonia fuel main engine 3 and the exhaust gas of the fuel oil equipment 4, the exhaust gas is cooled by seawater spraying in the pretreatment tower 26 and sulfur oxides are removed, and the remaining exhaust gas enters the absorption tower 24; the BOG in the liquid ammonia storage tank 11 enters the ammonia water tank 22 and mixes with fresh water to form ammonia water, the ammonia water is transported to the absorption tower 24 by the ammonia water pump 23 and sprayed out by the second spray device 241, the sprayed ammonia water reacts countercurrently with the carbon dioxide in the exhaust gas to generate ammonium bicarbonate solution, the ammonium bicarbonate solution can be discharged to the outside of the absorption tower 24 through the drain pipe 25. The system uses BOG gas in the liquid ammonia storage tank 11 as a CO2 absorbent to absorb CO2 emitted by the fuel equipment 4. This not only achieves near-zero CO2 emissions for the entire system, but also consumes and reuses the BOG gas in the liquid ammonia storage tank 11 to maintain stable pressure. This solves the problem of difficult-to-handle BOG from ammonia fuel, while also generating commercially valuable chemical fertilizer.

[0030] Furthermore, such as Figure 1 As shown, in this embodiment, the heating device 15 is a heat exchanger. A fuel supply main valve 66 is also provided between the outlet of the heating device 15 and the ammonia fuel main unit 3. The return port of the ammonia fuel main unit 3 is connected to the buffer tank 13 through the main unit return pipeline 18 to realize the return of part of the liquid ammonia (due to the characteristics of the ammonia fuel main unit 3, some unburned liquid ammonia will return during its operation).

[0031] Furthermore, such as Figure 1As shown, in this embodiment, the ammonia fuel supply unit 1 further includes a liquid ammonia supply pipeline 16. One end of the liquid ammonia supply pipeline 16 is connected to the pipeline between the outlet of the low-pressure supply pump 12 and the inlet of the buffer tank 13, and the other end of the liquid ammonia supply pipeline 16 is connected to the inlet of the ammonia water tank 22. When the ammonia water in the ammonia water tank 22 is insufficient and there is no sufficient ammonia gas in the liquid ammonia storage tank 11, some liquid ammonia can be pumped into the ammonia water tank 22 through the low-pressure supply pump 12 and the liquid ammonia supply pipeline 16 to supplement the ammonia water generated from fresh water.

[0032] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, a BOG supply regulating valve 61 is installed on the pipeline between the ammonia outlet of the liquid ammonia storage tank 11 and the inlet of the ammonia water tank 22; a liquid ammonia supply regulating valve 62 is installed on the liquid ammonia supply pipeline 16; and a freshwater regulating valve 63 is installed on the pipeline between the freshwater supply device 21 and the inlet of the ammonia water tank 22. A pressure sensor 111 is installed on the liquid ammonia storage tank 11 to detect the pressure value inside the liquid ammonia storage tank 11. A first level gauge 221 and a first pH meter 222 are installed on the ammonia water tank 22 to detect the liquid level and pH value of the ammonia water inside the ammonia water tank 22, respectively. The ship's ammonia fuel supply and exhaust gas treatment system also includes a control module 7, which is electrically connected to the BOG supply regulating valve 61, the liquid ammonia supply regulating valve 62, the freshwater regulating valve 63, the first level gauge 221, the first pH meter 222, and the pressure sensor 111. Specifically, in this embodiment, the freshwater supply device 21 includes a freshwater storage tank (not shown) and a freshwater supply pump (not shown). The freshwater storage tank is connected to the inlet of the freshwater supply pump, and the outlet of the freshwater supply pump is connected to the inlet of the ammonia tank 22. A freshwater regulating valve 63 is installed on the pipeline between the outlet of the freshwater supply pump and the inlet of the ammonia tank 22. The control module 7 is also electrically connected to the freshwater supply pump to control its operation. Of course, the freshwater supply device 21 can also be of other types.

[0033] Specifically, the ammonia in the ammonia tank 22 originates from BOG gas and liquid ammonia in the liquid ammonia storage tank 11. After a period of accumulation, when the pressure sensor 111 detects that the pressure in the liquid ammonia storage tank 11 has reached the discharge pressure, the control module 7 controls the BOG supply regulating valve 61 to open, and simultaneously controls the desalination regulating valve 63 to open, allowing the BOG gas in the liquid ammonia storage tank 11 and the desalination water in the desalination supply device 21 to simultaneously enter the ammonia tank 22. By monitoring the value of the first pH meter 222, a certain concentration of ammonia water is formed in the ammonia tank 22. When the pressure in the liquid ammonia storage tank 11 drops to a reasonable range, the control module 7 controls the BOG supply regulating valve 61 and the desalination regulating valve 63 to close.

[0034] When the first level gauge 221 detects that the ammonia level in the ammonia tank 22 has dropped to the set value, but the pressure in the liquid ammonia storage tank 11 has not yet reached the discharge pressure, the control module 7 controls the liquid ammonia supply regulating valve 62 and the fresh water regulating valve 63 to open, so that a portion of the liquid ammonia in the liquid ammonia storage tank 11 is pumped into the ammonia tank 22 by the low-pressure supply pump 12. By monitoring the value of the first pH meter 222, a certain concentration of ammonia water is formed in the ammonia tank 22.

[0035] Furthermore, such as Figure 1 As shown, in this embodiment, the ammonia fuel supply unit 1 further includes a liquid ammonia reflux pipeline 17. One end of the liquid ammonia reflux pipeline 17 is connected to the pipeline between the outlet of the low-pressure supply pump 12 and the inlet of the buffer tank 13, and the other end of the liquid ammonia reflux pipeline 17 is connected to the liquid ammonia storage tank 11. The liquid ammonia reflux pipeline 17 is used to regulate the flow rate of liquid ammonia pumped by the low-pressure supply pump 12 to the buffer tank 13. A reflux regulating valve 65 is provided on the liquid ammonia reflux pipeline 17 (for example, when the ammonia fuel main unit 3 is under low load, its liquid ammonia supply flow rate is reduced, and at this time the reflux regulating valve 65 is opened to allow a portion of the liquid ammonia to be pumped back to the liquid ammonia storage tank 11). One end of the liquid ammonia supply pipeline 16 is connected to the liquid ammonia return pipeline 17 (i.e., the liquid ammonia supply pipeline 16 is connected to the outlet of the low-pressure supply pump 12 through the liquid ammonia return pipeline 17), and the other end of the liquid ammonia supply pipeline 16 is connected to the pipeline between the ammonia outlet of the liquid ammonia storage tank 11 and the inlet of the ammonia water tank 22 (i.e., the liquid ammonia supply pipeline 16 is connected to the ammonia water tank 22 through the pipeline between the ammonia outlet of the liquid ammonia storage tank 11 and the inlet of the ammonia water tank 22), thereby saving pipeline space.

[0036] Furthermore, such as Figure 1 As shown, in this embodiment, a packing material 242 is provided in the middle of the absorption tower 24, located between the second spray device 241 and the bottom inlet of the absorption tower 24. The packing material 242 is used to increase the contact reaction time between ammonia and carbon dioxide in the tail gas, thereby enabling them to react more fully and improving the absorption efficiency.

[0037] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, a temperature sensor 64 is installed on the pipeline between the bottom outlet of the pretreatment tower 26 and the bottom inlet of the absorption tower 24; the control module 7 is also electrically connected to the temperature sensor 64 and the seawater supply device 27 respectively.

[0038] Specifically, since the temperature of the exhaust gas should not be too high, it is necessary to control the temperature of the exhaust gas entering the absorption tower 24. When the temperature sensor 64 detects that the temperature of the exhaust gas is too high, the control module 7 controls the seawater supply device 27 to increase the seawater supply flow rate, that is, to increase the seawater spray flow rate of the first spray device 261 in the pretreatment tower 26, thereby cooling the exhaust gas and reducing its temperature to a suitable level.

[0039] Specifically, in this embodiment, the seawater supply device 27 includes a seawater storage tank (not shown) and a seawater pump (not shown). The seawater storage tank is connected to the inlet of the seawater pump, and the outlet of the seawater pump is connected to the first spray device 261. The control module 7 is electrically connected to the seawater pump to control the flow rate of the seawater pump, thereby controlling the seawater supply flow rate of the seawater supply device 27.

[0040] Furthermore, such as Figure 1 As shown, in this embodiment, the exhaust gas treatment unit 2 further includes a water tank 28, which is connected to the top outlet of the absorption tower 24. The water tank 28 stores fresh water. When the remaining flue gas in the absorption tower 24 is discharged from the top of the tower into the water tank 28, the fresh water in the water tank 28 can absorb some of the ammonia carried in the flue gas, thereby preventing unreacted ammonia from being emitted into the atmosphere.

[0041] Furthermore, such as Figure 1 As shown, in this embodiment, the exhaust gas treatment unit 2 further includes a post-processor 29, and the drain pipe 25 is connected to the post-processor 29. The post-processor 29 is used to process the ammonium bicarbonate solution into solid ammonium bicarbonate. Specifically, in this embodiment, the post-processor 29 can perform cooling, crystallization, and dehydration treatment on the ammonium bicarbonate solution, thereby converting the ammonium bicarbonate solution into solid ammonium bicarbonate, which facilitates storage and transportation.

[0042] Furthermore, such as Figure 1 As shown, in this embodiment, the fuel-fired equipment 4 includes a fuel-fired boiler 41 and a fuel-fired generator 42. The exhaust outlets of both the fuel-fired boiler 41 and the fuel-fired generator 42 are connected to the inlet of the SCR denitrification device 5. Of course, in other embodiments, the fuel-fired equipment 4 can also be other equipment that uses fuel oil as fuel.

[0043] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, a second pH meter 243 is provided on the absorption tower 24. The second pH meter 243 is used to detect the pH value of the ammonium bicarbonate solution generated in the absorption tower 24. The control module 7 is also electrically connected to the second pH meter 243, the ammonia pump 23, and the fuel equipment 4 (including the fuel boiler 41 and the fuel generator 42). The pH value signal measured by the second pH meter 243 and the power signal of the fuel equipment 4 can be transmitted to the control module 7. The control module 7 is used to control the flow rate of the ammonia pump 23 according to the pH value measured by the second pH meter 243 and the current total power of the fuel equipment 4, so as to ensure that the ammonia water reacts fully with the carbon dioxide in the exhaust gas (i.e., the supply of ammonia water can be controlled as much as possible to react completely with the carbon dioxide in the exhaust gas). The set flow rate of the ammonia pump 23 satisfies the following conditions:

[0044] F 设定= k*P / α; where, F 设定 For the set flow rate of ammonia pump 23, F 设定 The control module 7 regulates and controls the ammonia pump 23; P is the current total power of the fuel equipment 4, k is the correlation coefficient between the flow rate of the ammonia pump 23 and the power of the fuel equipment 4 (the value of k is related to factors such as the type of fuel equipment 4 / combustion efficiency, reaction efficiency, and the concentration of ammonia in the ammonia tank 22, and the value of k can be obtained through actual empirical data. For example, when the concentration of ammonia in the ammonia tank 22 is kept constant, if the power of the fuel equipment 4 is 10KW, and the flow rate of the ammonia pump 23 is 5L / h, the ammonia just reacts completely with the carbon dioxide in the exhaust gas, then the value of k can be 2 (the unit of k is adaptively adjusted according to the power unit of the fuel equipment 4 and the flow rate unit of the ammonia pump 23). In actual operation, a data table related to the value of k can be established based on empirical data, and the value of k is obtained by looking up the table), α is the fine-tuning coefficient related to the pH value. Wherein, α = pH 测量值 / PH 饱和碳酸氢铵溶液 PH 测量值 The pH value measured by the second pH meter 243. 饱和碳酸氢铵溶液 This refers to the pH value of the saturated ammonium bicarbonate solution at the current temperature. (When ammonia reacts completely with carbon dioxide, the concentration of the resulting ammonium bicarbonate solution is exactly the same as the concentration of the saturated ammonium bicarbonate solution, and their pH values ​​are also the same. Therefore, the pH value of the saturated ammonium bicarbonate solution at the current temperature can be used as a reference to determine whether the ammonia has reacted completely with carbon dioxide. If there is too much ammonia, the excess ammonia will mix with the ammonium bicarbonate solution, resulting in a higher measured pH value; if there is too little ammonia, some unreacted carbon dioxide will dissolve in the water, resulting in a lower measured pH value.)

[0045] Specifically, since the exhaust gas emissions are mainly related to the power of the fuel system 4 (i.e., the carbon dioxide production is mainly related to the power of the fuel system 4), the set flow rate of the ammonia pump 23 can be coarsely adjusted based on the total power of the fuel system 4; then, based on the pH value measured by the second pH meter 243 on the absorption tower 24, the set flow rate of the ammonia pump 23 is precisely adjusted, so that the ammonia spray volume is precisely matched with the amount of carbon dioxide in the flue gas. The ammonia pump 23 is adjusted using PID control technology. The specific flow rate setting of the ammonia pump 23 is as follows:

[0046] (1) The current total power of the fuel system 4 is directly proportional to the set flow rate of the ammonia pump 23 (that is, the greater the current total power of the fuel system 4, the more carbon dioxide is produced, and the greater the set flow rate of the ammonia pump 23), thus yielding: F 设定 =k*P. The set flow rate of ammonia pump 23 is initially determined from the current total power of fuel equipment 4.

[0047] (2) The pH value measured by the second pH meter 243 is directly proportional to the set flow rate of the ammonia pump 23 (that is, the larger the pH value measured by the second pH meter 243, the more ammonia is in excess, and the smaller the set flow rate of the ammonia pump 23 should be), thus yielding: F 设定 =k*P / α, α=PH 测量值 / PH 饱和碳酸氢铵溶液 If the pH value measured by the second pH meter 243 is higher than the pH value of the saturated ammonium bicarbonate solution at the current temperature, it indicates that there is an excess of ammonia, and the set flow rate of the ammonia pump 23 is reduced; if the pH value measured by the second pH meter 243 is lower than the pH value of the saturated ammonium bicarbonate solution at the current temperature, it indicates that there is an insufficient amount of ammonia, and the set flow rate of the ammonia pump 23 is increased.

[0048] (3) Set the flow rate F of ammonia pump 23 to... 设定 The flow rate of the ammonia pump 23 is compared with the actual flow rate of the ammonia pump 23 (a flow meter can be installed at the outlet of the ammonia pump 23 for monitoring). After PID adjustment, the frequency of the ammonia pump 23 is controlled, thereby achieving precise control of the flow rate of the ammonia pump 23.

[0049] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, the absorption tower 24 is equipped with a second level gauge 244, which is used to detect the liquid level of the solution in the absorption tower 24. The control module 7 is also electrically connected to the second level gauge 244.

[0050] Furthermore, in this embodiment, each pipeline is also equipped with a corresponding control valve (not shown) to control the opening and closing of the corresponding pipeline.

[0051] like Figure 1 and Figure 2 As shown, the main working process of the ship ammonia fuel supply and exhaust gas treatment system in this embodiment of the invention is as follows:

[0052] 1. Liquid ammonia is stored in liquid ammonia storage tank 11. The liquid ammonia in liquid ammonia storage tank 11 is pumped to buffer tank 13 by low-pressure supply pump 12, and then pressurized and temperature-regulated by high-pressure pump 14 and heating device 15 before being supplied to ammonia fuel main unit 3 through fuel supply main valve 66 for combustion in ammonia fuel main unit 3. When the load of ammonia fuel main unit 3 decreases, excess liquid ammonia is pumped back to liquid ammonia storage tank 11 through liquid ammonia return pipeline 17.

[0053] 2. The exhaust gas from the ammonia-fueled main unit 3 contains nitrogen oxides, and the exhaust gas from the fuel-fired equipment 4 (including the fuel-fired boiler 41 and the fuel-fired generator 42) contains nitrogen oxides, sulfur oxides, and carbon dioxide. The exhaust gas from the ammonia-fueled main unit 3 and the fuel-fired equipment 4 are combined and then enter the SCR denitrification unit 5 to remove nitrogen oxides. The exhaust gas then enters the pretreatment tower 26. Seawater from the seawater supply unit 27 is sprayed into the pretreatment tower 26 through the first spray device 261. The sprayed seawater mixes and reacts with the exhaust gas in the pretreatment tower 26, which cools the exhaust gas and removes sulfur oxides. The exhaust gas treated with seawater enters the absorption tower 24 through the bottom inlet. The seawater sprayed in the pretreatment tower 26 is discharged from the bottom of the pretreatment tower 26.

[0054] 3. Fresh water supplied by the fresh water supply device 21 enters the ammonia tank 22, where it is mixed with BOG gas or liquid ammonia from the liquid ammonia storage tank 11 to form ammonia water of a certain concentration. The ammonia tank 22 is equipped with a first level gauge 221 and a first pH meter 222 to monitor the liquid level and ammonia concentration within the tank. The ammonia water in the ammonia tank 22 is pumped to the absorption tower 24 by the ammonia pump 23 and sprayed from top to bottom by the second spray device 241. The sprayed ammonia water comes into countercurrent contact with the tail gas from the pretreatment tower 26; that is, ammonia water is sprayed at the top of the absorption tower 24, while tail gas is introduced at the bottom. Simultaneously, the packing material 242 increases the contact reaction time between the two, allowing the ammonia water and carbon dioxide in the tail gas to fully mix and react to generate ammonium bicarbonate solution. The absorption tower 24 is equipped with a second pH meter 243 and a second level gauge 244 to monitor the liquid level and carbon dioxide absorption status within the tower. The ammonium bicarbonate solution generated in the absorption tower 24 enters the post-processor 29 through the drain pipe 25. After being cooled, crystallized and dehydrated by the post-processor 29, it forms solid ammonium bicarbonate.

[0055] 4. The water tank 28 stores fresh water. When the remaining flue gas in the absorption tower 24 is discharged from the top of the tower into the water tank 28, the fresh water in the water tank 28 can absorb some of the ammonia carried in the flue gas, thereby preventing unreacted ammonia from being emitted into the atmosphere. After the above-mentioned denitrification, desulfurization and decarbonization treatment, the ship's exhaust gas achieves near-zero emissions.

[0056] The marine ammonia fuel supply and exhaust gas treatment system provided in this invention aims to achieve zero pollution emissions from ships and solve the problem of difficult-to-treat BOG gas in ammonia fuel supply systems. This system uses BOG gas and / or liquid ammonia in liquid ammonia storage tank 11 as a CO2 absorbent to absorb CO2 emitted from the fuel equipment 4. This not only achieves near-zero CO2 emissions for the entire system but also consumes and reuses the BOG gas in liquid ammonia storage tank 11 to maintain stable pressure. This solves the problem of difficult-to-treat BOG from ammonia fuel while simultaneously generating commercially valuable chemical fertilizers.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A ship ammonia fuel supply and exhaust gas treatment system, characterized in that, It includes an ammonia fuel supply unit (1), a tail gas treatment unit (2), an ammonia fuel main unit (3) using liquid ammonia as fuel, a fuel oil equipment (4) using fuel oil as fuel, an SCR denitrification device (5), and a control module (7); the ammonia fuel supply unit (1) includes a liquid ammonia storage tank (11), a low-pressure supply pump (12), a buffer tank (13), a high-pressure pump (14), and a heating device (15); the tail gas treatment unit (2) includes a fresh water supply device (21), an ammonia water tank (22), an ammonia water pump (23), an absorption tower (24), a drain pipeline (25), a pretreatment tower (26), and a seawater supply device (27); The inlet of the low-pressure supply pump (12) is connected to the liquid ammonia storage tank (11), the outlet of the low-pressure supply pump (12) is connected to the inlet of the buffer tank (13), the outlet of the buffer tank (13) is connected to the inlet of the high-pressure pump (14), the outlet of the high-pressure pump (14) is connected to the inlet of the heating device (15), and the outlet of the heating device (15) is connected to the ammonia fuel main unit (3). The exhaust outlets of the ammonia fuel main unit (3) and the fuel oil equipment (4) are both connected to the inlet of the SCR denitrification device (5), and the outlet of the SCR denitrification device (5) is connected to the top inlet of the pretreatment tower (26); a first spray device (261) is provided at the top of the pretreatment tower (26), and the seawater supply device (27) is connected to the first spray device (261); the bottom outlet of the pretreatment tower (26) is connected to the bottom inlet of the absorption tower (24); The ammonia outlet of the liquid ammonia storage tank (11) and the fresh water supply device (21) are both connected to the inlet of the ammonia water tank (22), and the outlet of the ammonia water tank (22) is connected to the inlet of the ammonia water pump (23); a second spray device (241) is provided at the top of the absorption tower (24), the outlet of the ammonia water pump (23) is connected to the second spray device (241), and the drain pipe (25) is connected to the bottom outlet of the absorption tower (24); The absorption tower (24) is equipped with a second pH meter (243), which is used to detect the pH value of the ammonium bicarbonate solution generated in the absorption tower (24). The control module (7) is electrically connected to the second pH meter (243), the ammonia pump (23), and the fuel equipment (4). The control module (7) is used to control the flow rate of the ammonia pump (23) according to the pH value measured by the second pH meter (243) and the current total power of the fuel equipment (4). The set flow rate of the ammonia pump (23) meets the following conditions: F 设定 =k P / α; where F 设定 Let P be the set flow rate of the ammonia pump (23), P be the current total power of the fuel equipment (4), k be the correlation coefficient between the flow rate of the ammonia pump (23) and the power of the fuel equipment (4), and α be the fine-tuning coefficient related to the pH value; where α = pH 测量值 / PH 饱和碳酸氢铵溶液 PH 测量值 The pH value measured by the second pH meter (243) is PH. 饱和碳酸氢铵溶液 This represents the pH value of the saturated ammonium bicarbonate solution at the current temperature.

2. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 1, characterized in that, The ammonia fuel supply unit (1) also includes a liquid ammonia supply pipeline (16), one end of which is connected to the pipeline between the outlet of the low-pressure supply pump (12) and the inlet of the buffer tank (13), and the other end of which is connected to the inlet of the ammonia water tank (22).

3. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 2, characterized in that, A BOG supply regulating valve (61) is provided on the pipeline between the ammonia outlet of the liquid ammonia storage tank (11) and the inlet of the ammonia water tank (22). A liquid ammonia supply regulating valve (62) is provided on the liquid ammonia supply pipeline (16). A fresh water regulating valve (63) is provided on the pipeline between the fresh water supply device (21) and the inlet of the ammonia water tank (22). A pressure sensor (111) is provided on the liquid ammonia storage tank (11). A first level gauge (221) and a first pH meter (222) are provided on the ammonia water tank (22). The control module (7) is electrically connected to the BOG supply regulating valve (61), the liquid ammonia supply regulating valve (62), the fresh water regulating valve (63), the first level gauge (221), the first pH meter (222), and the pressure sensor (111), respectively.

4. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 2, characterized in that, The ammonia fuel supply unit (1) further includes a liquid ammonia reflux pipeline (17), one end of which is connected to the pipeline between the outlet of the low-pressure supply pump (12) and the inlet of the buffer tank (13), and the other end of which is connected to the liquid ammonia storage tank (11); one end of the liquid ammonia supply pipeline (16) is connected to the liquid ammonia reflux pipeline (17), and the other end of which is connected to the pipeline between the ammonia outlet of the liquid ammonia storage tank (11) and the inlet of the ammonia water tank (22).

5. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 1, characterized in that, The absorption tower (24) is provided with packing material (242) in the middle position, and the packing material (242) is located between the second spray device (241) and the bottom inlet of the absorption tower (24).

6. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 1, characterized in that, A temperature sensor (64) is installed on the pipeline between the bottom outlet of the pretreatment tower (26) and the bottom inlet of the absorption tower (24); the control module (7) is electrically connected to the temperature sensor (64) and the seawater supply device (27) respectively.

7. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 1, characterized in that, The exhaust gas treatment unit (2) also includes a water tank (28), which is connected to the top outlet of the absorption tower (24).

8. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 1, characterized in that, The exhaust gas treatment unit (2) further includes a post-processor (29), the drain pipe (25) is connected to the post-processor (29), and the post-processor (29) is used to process ammonium bicarbonate solution into ammonium bicarbonate solid.

9. The ship ammonia fuel supply and exhaust gas treatment system as described in claim 1, characterized in that, The fuel equipment (4) includes a fuel boiler (41) and a fuel generator (42), and the exhaust outlets of the fuel boiler (41) and the fuel generator (42) are both connected to the inlet of the SCR denitrification device (5).

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