Ammonia fuel supply system

Abstract

The application discloses an ammonia fuel supply system, comprising a fuel storage tank, a primary booster pump, a full-liquid buffer tank, a diaphragm pump, a temperature regulating unit, a valve group unit and a main engine, wherein the full-liquid buffer tank comprises a front buffer tank and a rear buffer tank; the fuel storage tank is used for storing liquid ammonia, an inlet pipe of the primary booster pump extends into the fuel storage tank, an outlet of the primary booster pump is connected with an inlet of the front buffer tank, an outlet of the front buffer tank is connected with an inlet of the diaphragm pump, an outlet of the diaphragm pump is connected with an inlet of the rear buffer tank, and an outlet of the rear buffer tank is connected with an inlet of the temperature regulating unit, and the temperature regulating unit is sequentially connected with the valve group unit and the main engine. The stable and reliable operation of the ammonia fuel supply system buffer process is realized by adopting the full-liquid buffer tank.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fuel supply systems, and particularly relates to an ammonia fuel supply system. BACKGROUND

[0002] With the aggravation of global warming, reducing greenhouse gas emissions has become an important task facing the world today. Increasing the proportion of zero-carbon or low-carbon energy in the world's energy consumption structure helps to reduce greenhouse gas emissions and promote the realization of the global carbon cycle system “carbon neutralization”. In the field of ship navigation, ammonia as a zero-carbon fuel has attracted widespread attention. As a fuel for ship engines, ammonia is usually stored in the form of normal-pressure liquid ammonia at -33 DEG C in a fuel storage tank, and needs to be pressurized and temperature-adjusted before being supplied for combustion. The supply pressure of a large two-stroke ammonia fuel main engine is about 84 bar, and usually needs two-stage pressurization, that is, first, a primary pressurization pump is used to pump liquid ammonia out of the fuel tank, and then a high-pressure pump is used for secondary pressurization.

[0003] The ammonia fuel supply flow is generally less than 20 m 3 / h, and the high-pressure pump in this flow range is usually a leak-free diaphragm pump. The diaphragm pump produces periodic flow fluctuations during operation, which further causes supply pressure fluctuations, and needs to be used with a buffer device in the application process. The current commonly used buffer device is a gas-liquid contact type or a gas bag type buffer, and the gas-liquid contact type buffer needs to consider the control of the inert gas inlet and outlet, and the operation is complex; the gas bag type buffer is prone to fatigue failure due to periodic movement of the gas bag. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide an ammonia fuel supply system, which aims to solve the problems in the background art, and realizes stable and reliable operation of the ammonia fuel supply system buffer process by using a full-liquid buffer tank to solve the problems of complex operation of the gas-liquid contact type buffer and fatigue failure caused by periodic movement of the gas bag type buffer.

[0005] The present application provides an ammonia fuel supply system, comprising: a fuel storage tank, a primary pressurization pump, a full-liquid buffer tank, a diaphragm pump, a temperature-adjusting unit, a valve group unit and a main engine, wherein the full-liquid buffer tank comprises a pre-buffer tank and a post-buffer tank; the fuel storage tank is used for storing liquid ammonia, the inlet pipe of the primary pressurization pump extends into the fuel storage tank, the outlet of the primary pressurization pump is in communication with the inlet of the pre-buffer tank, the outlet of the pre-buffer tank is in communication with the inlet of the diaphragm pump, the outlet of the diaphragm pump is in communication with the inlet of the post-buffer tank, and the outlet of the post-buffer tank is in communication with the inlet of the temperature-adjusting unit, and the temperature-adjusting unit is in communication with the valve group unit and the main engine in sequence.

[0006] Further, the volume of the full liquid buffer tank is V, the maximum fluctuation volume generated in a single cycle of the diaphragm pump is determined according to the number of pump heads, the motor shaft speed, and the fuel supply flow, and is calculated by the following formula:

[0007]

[0008] wherein Q is the fuel flow, g r is the gear reduction ratio, n1 is the motor shaft speed of the pump; k is the flow unevenness coefficient, and n2 is the number of flow fluctuation cycles, both of which are determined by the number of pump heads; the volume V of the required full liquid buffer tank is determined according to the maximum fluctuation volume, the maximum pressure fluctuation degree required by the fuel supply, and the fuel density property at the port near the end of the diaphragm pump close to the full liquid buffer tank, and is calculated by the following formula:

[0009]

[0010] wherein AV is the maximum fluctuation volume in a single cycle of the diaphragm pump; p is the density value corresponding to the average fuel supply pressure at the port near the end of the diaphragm pump close to the full liquid buffer tank at the supply temperature; p ± is the density value corresponding to the upper and lower limits of the pressure fluctuation required by the fuel supply at the port near the end of the diaphragm pump close to the full liquid buffer tank at the supply temperature, and the maximum value calculated from the upper and lower limits of the pressure fluctuation is taken as the volume V of the full liquid buffer tank.

[0011] Further, the volume of the front buffer tank is V1, and the volume V1 of the required front buffer tank is determined according to the maximum fluctuation volume, the maximum pressure fluctuation degree required by the fuel supply, and the fuel density property at the inlet near the end of the diaphragm pump close to the front buffer tank, and is calculated by the following formula:

[0012]

[0013] wherein p1 is the density value corresponding to the average fuel supply pressure at the inlet near the end of the diaphragm pump close to the front buffer tank at the supply temperature; p 1± is the density value corresponding to the upper and lower limits of the pressure fluctuation required by the fuel supply at the inlet near the end of the diaphragm pump close to the front buffer tank at the supply temperature, and the maximum value calculated from the upper and lower limits of the pressure fluctuation is taken as the volume V1 of the front buffer tank.

[0014] Further, the volume of the rear buffer tank is V2, and the volume V2 of the required rear buffer tank is determined according to the maximum fluctuation volume, the maximum pressure fluctuation degree required by the fuel supply, and the fuel density property at the outlet near the end of the diaphragm pump close to the rear buffer tank, and is calculated by the following formula:

[0015]

[0016] Wherein, ρ2 is the density value corresponding to the average value of the fuel supply pressure at the outlet of the diaphragm pump close to the one end of the post-buffer tank at the supply temperature; ρ 2± is the density value corresponding to the upper limit and lower limit of the pressure fluctuation required for the fuel supply at the outlet of the diaphragm pump close to the one end of the post-buffer tank at the supply temperature, and the maximum value calculated by the upper limit and lower limit of the pressure fluctuation is taken as the volume V2 of the post-buffer tank.

[0017] Further, the primary booster pump is a sliding vane pump, and the sliding vane pump is arranged at the top of the fuel tank, and an inlet pipe of the sliding vane pump penetrates into the bottom of the fuel tank.

[0018] Further, the ammonia fuel supply system further comprises a fuel filter, and the fuel filter is arranged on the pipeline between the primary booster pump and the diaphragm pump.

[0019] Further, the front-buffer tank is provided with a first pressure sensor, and the first pressure sensor is interlocked with the primary booster pump; and the post-buffer tank is provided with a second pressure sensor, and the second pressure sensor is interlocked with the diaphragm pump.

[0020] Further, a first check valve is arranged on the pipeline between the primary booster pump and the front-buffer tank, and a second check valve is arranged on the pipeline between the diaphragm pump and the post-buffer tank.

[0021] Further, the top and bottom of the front-buffer tank are respectively provided with a first safety valve and a first relief valve; and the top and bottom of the post-buffer tank are respectively provided with a second safety valve and a second relief valve.

[0022] Further, the ammonia fuel supply system further comprises an ammonia treatment unit, and the outlets of the first safety valve, the first relief valve, the second safety valve and the second relief valve are connected to the ammonia treatment unit.

[0023] Further, a first pneumatic stop valve is arranged on the pipeline between the front-buffer tank and the diaphragm pump, and a second pneumatic stop valve is arranged on the pipeline between the post-buffer tank and the temperature regulating unit.

[0024] Further, the control method of the ammonia fuel supply system comprises the following steps:

[0025] The liquid ammonia is pumped from the fuel tank to the front-buffer tank by the primary booster pump and is subjected to primary pressure boosting;

[0026] The liquid ammonia in the front-buffer tank is further boosted to the required pressure of the host engine by the diaphragm pump and is pumped to the post-buffer tank;

[0027] The liquid ammonia subjected to secondary pressure boosting is heated to the required temperature by the temperature regulating unit and is delivered to the host engine for combustion by the valve group unit.

[0028] The ammonia fuel supply system provided by the present application solves the problems of complex operation of the common gas-liquid contact type buffer and fatigue failure of the periodic movement of the air bag type buffer by setting full liquid buffer tanks before the inlet and after the outlet of the diaphragm pump respectively, and uses the compressibility of the liquid at a specific volume to keep the periodic fluctuation of the inlet and outlet pressures of the diaphragm pump within the allowable range, thereby realizing stable and reliable operation of the buffer process of the ammonia fuel supply system. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The figure is a structural schematic diagram of the ammonia fuel supply system of the embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will describe in detail the specific embodiments of the present application in combination with the drawings. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the description of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] The terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer" and the like in the specification and claims of the present application indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of description and simplification of description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0033] The terms "first", "second", "third" and the like in the specification and claims of the present application are only for distinguishing similar attributes of elements, and do not indicate or imply relative importance or a particular order.

[0034] The terms "include", "contain" or any other variants thereof in the specification and claims of the present application are intended to cover non-exclusive inclusion, in addition to the listed elements, and can also include other elements not explicitly listed.

[0035] The present application provides an ammonia fuel supply system, as shown inFigure 1 As shown, it comprises a fuel tank 1, a primary booster pump 3, a full liquid buffer tank, a diaphragm pump 6, a temperature regulating unit 9, a valve group unit 10 and a main engine 11. The fuel tank 1 is used for storing liquid ammonia, the inlet pipe of the primary booster pump 3 extends into the fuel tank 1, the primary booster pump 3 pumps out liquid ammonia from the fuel tank 1 and performs primary boosting. The full liquid buffer tank comprises a front buffer tank 4 and a rear buffer tank 8. The outlet of the primary booster pump 3 is communicated with the inlet of the front buffer tank 4, the outlet of the front buffer tank 4 is communicated with the inlet of the diaphragm pump 6, the outlet of the diaphragm pump 6 is communicated with the inlet of the rear buffer tank 8, the outlet of the rear buffer tank 8 is communicated with the inlet of the temperature regulating unit 9, the temperature regulating unit 9 is communicated with the valve group unit 10 and the main engine 11 in sequence. The liquid ammonia after primary boosting enters the front buffer tank 4 for the first time, then enters the diaphragm pump 6 for secondary boosting, then enters the rear buffer tank 8 for the second time, and then enters the temperature regulating unit 9 for temperature regulation. The temperature regulating unit 9 is communicated with the valve group unit 10 and the main engine 11 in sequence, that is, the liquid ammonia after temperature regulation by the temperature regulating unit 9 enters the main engine 11 for combustion through the valve group unit 10. The devices are connected by pipelines. The ammonia fuel supply system provided by the application solves the problems of complex operation of the commonly used gas-liquid contact type buffer and fatigue failure of the gas bag type buffer due to periodic movement by arranging the full liquid buffer tank before the inlet and after the outlet of the diaphragm pump 6, and the periodic fluctuation of the inlet and outlet pressures of the diaphragm pump 6 is kept within the allowable range by using the compressibility of the liquid in a specific volume, so that the stable and reliable operation of the ammonia fuel supply system in the buffering process is realized.

[0036] As an embodiment, the volume of the full liquid buffer tank is V, the maximum fluctuation volume generated by the diaphragm pump 6 in a single cycle is determined according to the number of pump heads, the motor shaft speed and the fuel supply flow, and is calculated by the following formula:

[0037]

[0038] Wherein, Q is the fuel flow, g r is the gear reduction ratio, n1 is the motor shaft speed of the pump; k is the flow unevenness coefficient, n2 is the number of flow fluctuation cycles, both of which are determined by the number of pump heads; Table 1 shows the relationship between the flow unevenness coefficient k and the number of flow fluctuation cycles n2 and the number of liquid cylinders z of the reciprocating pump, wherein k takes the value with larger absolute value in k1 and k2; wherein the diaphragm pump 6 belongs to the reciprocating pump.

[0039] Table 1 Flow unevenness coefficient and flow fluctuation cycle number of single-acting reciprocating pump with different cylinder numbers

[0040] Number of liquid cylinders z [n2] ​ [ k2 ] 1 1 2.14 -1.0 2 2 0.57 -1.0 3 6 0.05 -0.09 4 4 0.11 -0.21 5 / 0.02 -0.04

[0041] The volume V of the full-liquid buffer tank required is determined according to the maximum fluctuation volume, the maximum pressure fluctuation required for fuel supply, and the density properties of the fuel at the port of the diaphragm pump 6 close to one end of the full-liquid buffer tank, and is calculated by the following formula:

[0042]

[0043] wherein ΔV is the maximum fluctuation volume in one cycle of the diaphragm pump 6; ρ is the density value corresponding to the average value of the fuel supply pressure at the port of the diaphragm pump 6 close to one end of the full-liquid buffer tank at the supply temperature; ρ ± is the density value corresponding to the upper and lower limits of the pressure fluctuation required for the fuel supply at the port of the diaphragm pump 6 close to one end of the full-liquid buffer tank at the supply temperature, and the maximum value calculated from the upper and lower limits of the pressure fluctuation is taken as the volume V of the full-liquid buffer tank. In this embodiment, the volume of the full-liquid buffer tank required can be calculated through the above calculation process, and stable and reliable operation of the buffer process can be achieved by providing a full-liquid buffer tank with a specific volume, thereby improving the stability of the ammonia fuel supply system.

[0044] As an embodiment, the volume of the pre-buffer tank 4 is V1, and the volume V1 of the pre-buffer tank 4 required is determined according to the maximum fluctuation volume, the maximum pressure fluctuation required for fuel supply, and the density properties of the fuel at the inlet of the diaphragm pump 6 close to one end of the pre-buffer tank 4, and is calculated by the following formula:

[0045]

[0046] wherein ρ1 is the density value corresponding to the average value of the fuel supply pressure at the inlet of the diaphragm pump 6 close to one end of the pre-buffer tank 4 at the supply temperature; ρ 1± is the density value corresponding to the upper and lower limits of the pressure fluctuation required for the fuel supply at the inlet of the diaphragm pump 6 close to one end of the pre-buffer tank 4 at the supply temperature, and the maximum value calculated from the upper and lower limits of the pressure fluctuation is taken as the volume V1 of the pre-buffer tank 4.

[0047] As an embodiment, the volume of the post-buffer tank 8 is V2, and the volume V2 of the post-buffer tank 8 required is determined according to the maximum fluctuation volume, the maximum pressure fluctuation required for fuel supply, and the density properties of the fuel at the outlet of the diaphragm pump 6 close to one end of the post-buffer tank 8, and is calculated by the following formula:

[0048]

[0049] wherein ρ2 is the density value corresponding to the average value of the fuel supply pressure at the outlet of the diaphragm pump 6 close to one end of the post-buffer tank 8 at the supply temperature; ρ 2±The density value corresponding to the upper limit and the lower limit of the pressure fluctuation required for the fuel supply at the outlet of the diaphragm pump 6 close to one end of the post-buffer tank 8 is taken as the maximum value calculated by the upper limit and the lower limit of the pressure fluctuation, and the volume V2 of the post-buffer tank 8 is taken as the maximum value.

[0050] As an embodiment, the primary booster pump 3 is a sliding vane pump, which is arranged at the top of the fuel tank 1, and the inlet pipe of the sliding vane pump is deep into the bottom of the fuel tank 1. The supply pressure of a large two-stroke ammonia fuel main engine is about 84 bar, and generally two-stage boosting is required, that is, the liquid ammonia is first pumped out of the fuel tank 1 by the primary booster pump 3, and then the high-pressure pump is used for secondary boosting. The single-layer C-type tank is commonly used as the fuel tank, and the liquid cargo inlet and outlet of the tank are generally opened at the top to prevent leakage. To meet the lift requirement, the primary booster pump used for the single-layer C-type tank is generally a centrifugal deep-well pump. The centrifugal deep-well pump has good continuity, but its cost is relatively high and its operating efficiency is relatively low. The sliding vane pump is a positive displacement pump with good continuity, which can realize top liquid delivery, and has the advantages of high operating efficiency, stable flow, convenient maintenance, and relatively low cost compared with the centrifugal deep-well pump, and has high cost performance.

[0051] As an embodiment, as shown in Figure 1 the ammonia fuel supply system further comprises a fuel filter 2 arranged on the pipeline between the primary booster pump 3 and the diaphragm pump 6. In this embodiment, by arranging the fuel filter 2 before the high-pressure pump, that is, before the diaphragm pump 6, the allowable pressure of the filter can be reduced, and the equipment cost can be reduced. The design pressure of the fuel filter 2 is referred to the outlet pressure value of the primary booster pump 3. Further, the fuel filter 2 is arranged between the primary booster pump 3 and the pre-buffer tank 4.

[0052] As an embodiment, as shown in Figure 1 the pre-buffer tank 4 is provided with a first pressure sensor 5, and the first pressure sensor 5 is interlocked with the primary booster pump 3. The flow of the primary booster pump 3 is controlled by the first pressure sensor 5, so as to maintain the stable pressure of the pre-buffer tank 4. The post-buffer tank 8 is provided with a second pressure sensor 7, and the second pressure sensor 7 is interlocked with the diaphragm pump 6. The flow of the diaphragm pump 6 is controlled by the second pressure sensor 7, so as to maintain the stable pressure of the post-buffer tank 8.

[0053] As an embodiment, as shown in Figure 1 the pipeline between the primary booster pump 3 and the pre-buffer tank 4 is provided with a first check valve V1, so that the liquid ammonia can only flow from the primary booster pump 3 to the pre-buffer tank 4, and the backflow of the liquid ammonia can be prevented. The pipeline between the diaphragm pump 6 and the post-buffer tank 8 is provided with a second check valve V5, so that the liquid ammonia can only flow from the diaphragm pump 6 to the post-buffer tank 8, and the backflow of the liquid ammonia can be prevented.

[0054] As an embodiment, as shown in Figure 1As shown, the top of the front buffer tank 4 is provided with a first safety valve V2, and the bottom of the front buffer tank 4 is provided with a first relief valve V3. The top of the rear buffer tank 8 is provided with a second safety valve V6, and the bottom of the rear buffer tank 8 is provided with a second relief valve V7. During the transportation of liquid ammonia, when the gas pressure in the front buffer tank 4 is greater than the set value, the first safety valve V2 is opened to discharge ammonia gas, preventing the front buffer tank 4 from abnormally increasing in pressure and improving the safety of the front buffer tank 4; when the gas pressure in the rear buffer tank 8 is greater than the set value, the second safety valve V6 is opened to discharge ammonia gas, preventing the rear buffer tank 8 from abnormally increasing in pressure and improving the safety of the rear buffer tank 8. When the ammonia fuel supply system needs to be shut down for maintenance or is abnormal, the first relief valve V3 and the second safety valve V6 can be opened to discharge the liquid ammonia in the front buffer tank 4 and the rear buffer tank 8.

[0055] As an embodiment, as shown in the figure, Figure 1 As shown, the ammonia fuel supply system further comprises an ammonia gas treatment unit 12, and the outlets of the first safety valve V2, the first relief valve V3, the second safety valve V6 and the second relief valve V7 are connected to the ammonia gas treatment unit 12, and the discharged ammonia gas or the discharged liquid ammonia is treated by the ammonia gas treatment unit 12.

[0056] As an embodiment, as shown in the figure, Figure 1 As shown, a first pneumatic stop valve V4 is arranged on the pipeline between the front buffer tank 4 and the diaphragm pump 6, and a second pneumatic stop valve V8 is arranged on the pipeline between the rear buffer tank 8 and the temperature regulating unit 9.

[0057] As an embodiment, the control method of the ammonia fuel supply system comprises the following steps:

[0058] The liquid ammonia is pumped from the fuel tank 1 to the front buffer tank 4 by the primary booster pump 3 and is subjected to primary boosting, and the liquid ammonia is subjected to first buffering in the front buffer tank 4;

[0059] The liquid ammonia in the front buffer tank 4 is further boosted to the required pressure of the main engine 11 by the diaphragm pump 6 and is pumped to the rear buffer tank 8 for second buffering;

[0060] The liquid ammonia in the rear buffer tank 8 after being boosted again is heated to the required temperature of the main engine 11 by the temperature regulating unit 9 and is delivered to the main engine 11 for combustion by the valve group unit 10.

[0061] The beneficial effects of the embodiment of the present application are:

[0062] (1) The present application uses a sliding vane pump as a low-pressure pump, which can realize liquid delivery at the top of the tank, and has high efficiency, stable flow and convenient maintenance.

[0063] (2) The fuel filter of the present application is arranged in front of the high-pressure pump, which can reduce the allowable pressure of the filter and reduce the equipment cost.

[0064] (3) The application adopts full-liquid buffer tank as front and back buffers of high-pressure pump, and uses compressibility of liquid under specific volume to keep periodic fluctuation of inlet and outlet pressure of diaphragm pump 6 within allowable range. The buffer scheme is simple, stable and reliable.

[0065] The above is only the preferred embodiment of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the technical solution range of the present application, and the equivalent embodiments with equivalent changes are obtained. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solution content of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. An ammonia fuel supply system characterized by comprising: The ammonia fuel supply system comprises a fuel tank (1), a primary booster pump (3), a full liquid buffer tank, a diaphragm pump (6), a temperature regulating unit (9), a valve group unit (10) and a main engine (11), wherein the full liquid buffer tank comprises a front buffer tank (4) and a rear buffer tank (8); the fuel tank (1) is used for storing liquid ammonia; an inlet pipe of the primary booster pump (3) extends into the fuel tank (1); an outlet of the primary booster pump (3) is communicated with an inlet of the front buffer tank (4); an outlet of the front buffer tank (4) is communicated with an inlet of the diaphragm pump (6); an outlet of the diaphragm pump (6) is communicated with an inlet of the rear buffer tank (8); an outlet of the rear buffer tank (8) is communicated with an inlet of the temperature regulating unit (9); the temperature regulating unit (9) is sequentially communicated with the valve group unit (10) and the main engine (11). The primary booster pump (3) is a sliding vane pump, which is arranged on the top of the fuel tank (1), and an inlet pipe of the sliding vane pump extends to the bottom of the fuel tank (1). The full-liquid buffer tank has a volume of V The maximum fluctuation volume generated by the diaphragm pump (6) in a single cycle is determined according to the number of pump heads, the motor shaft rotation speed, and the fuel supply flow rate of the diaphragm pump (6) and is calculated by the following formula: wherein, Q is the fuel flow rate, g r is the gear reduction ratio, n 1 is the motor shaft speed of the pump; k is the flow rate unevenness coefficient, n 2 is the number of flow rate fluctuation cycles, both of which are determined by the number of pump heads; the volume of the full liquid buffer tank is determined according to the maximum fluctuation volume, the maximum pressure fluctuation degree required by fuel supply, and the fuel density physical property at the port of the diaphragm pump (6) close to one end of the full liquid buffer tank V , which is calculated by the following formula: wherein, △V is the maximum fluctuation volume in a single cycle of the diaphragm pump (6); The ammonia fuel supply system further comprises a fuel filter (2), which is arranged on a pipeline between the primary booster pump (3) and the diaphragm pump (6). is the density value corresponding to the average value of the fuel supply pressure at the port of the diaphragm pump (6) near the full liquid buffer tank end at the supply temperature; A first pressure sensor (5) is arranged on the front buffer tank (4) and is interlocked with the primary booster pump (3); a second pressure sensor (7) is arranged on the rear buffer tank (8) and is interlocked with the diaphragm pump (6). ± is the density value corresponding to the upper limit and lower limit of the pressure fluctuation required for the fuel supply at the port of the diaphragm pump (6) near the full liquid buffer tank end at the supply temperature, and the maximum value calculated from the upper limit and lower limit of the pressure fluctuation is taken as the volume of the full liquid buffer tank V .

2. The ammonia fuel supply system according to claim 1, characterized by The volume of the pre-buffer tank (4) is V 1. The volume of the pre-buffer tank (4) is determined by the maximum fluctuation volume, the maximum pressure fluctuation degree required for fuel supply, and the fuel density physical property at the inlet of the diaphragm pump (6) near one end of the pre-buffer tank (4) V 1. Calculated from the following equation: wherein, A first check valve (V1) is arranged on a pipeline between the primary booster pump (3) and the front buffer tank (4); a second check valve (V5) is arranged on a pipeline between the diaphragm pump (6) and the rear buffer tank (8). 1 is the density value corresponding to the average value of the fuel supply pressure at the inlet of the diaphragm pump (6) near one end of the pre-buffer tank (4) at the supply temperature; A first safety valve (V2) and a first relief valve (V3) are respectively arranged on the top and the bottom of the front buffer tank (4); a second safety valve (V6) and a second relief valve (V7) are respectively arranged on the top and the bottom of the rear buffer tank (8). 1± 1± is the density value corresponding to the upper limit and lower limit of the pressure fluctuation required for fuel supply at the inlet of the diaphragm pump (6) near one end of the pre-buffer tank (4) at the supply temperature, and the maximum value calculated from the upper limit and lower limit of the pressure fluctuation is taken as the volume of the pre-buffer tank (4) V 1.

3. The ammonia fuel supply system according to claim 1, wherein The volume of the post-buffer tank (8) is V 2, the volume of the post-buffer tank (8) is determined from the maximum fluctuation volume, the maximum pressure fluctuation degree required for fuel supply, and the fuel density physical property at the outlet of the diaphragm pump (6) near one end of the post-buffer tank (8) V 2, calculated from the following equation: wherein, The ammonia fuel supply system further comprises an ammonia gas treatment unit (12), and outlets of the first safety valve (V2), the first relief valve (V3), the second safety valve (V6) and the second relief valve (V7) are connected to the ammonia gas treatment unit (12). 2 is the density value corresponding to the upper limit and lower limit of the pressure fluctuation required for fuel supply at the outlet of the diaphragm pump (6) near one end of the post-buffer tank (8) at the supply temperature, and the maximum value calculated from the upper limit and lower limit of the pressure fluctuation is taken as the volume of the post-buffer tank (8) A first pneumatic stop valve (V4) is arranged on a pipeline between the front buffer tank (4) and the diaphragm pump (6); a second pneumatic stop valve (V8) is arranged on a pipeline between the rear buffer tank (8) and the temperature regulating unit (9). 2± 2 is the density value corresponding to the upper limit and lower limit of the pressure fluctuation required for fuel supply at the outlet of the diaphragm pump (6) near one end of the post-buffer tank (8) at the supply temperature, and the maximum value calculated from the upper limit and lower limit of the pressure fluctuation is taken as the volume of the post-buffer tank (8) V 2.

4. The ammonia fuel supply system according to claim 1, wherein The control method of the ammonia fuel supply system comprises the following steps:

5. The ammonia fuel supply system according to claim 1, wherein The primary booster pump (3) is used for pumping liquid ammonia from the fuel tank (1) to the front buffer tank (4) and performing primary boosting; 6. The ammonia fuel supply system according to claim 1, wherein The liquid ammonia in the front buffer tank (4) is further boosted to a required pressure of the main engine (11) by the diaphragm pump (6) and is pumped to the rear buffer tank (8); 7. The ammonia fuel supply system according to claim 1, wherein The temperature regulating unit (9) is used for heating the liquid ammonia after secondary boosting to a required temperature, and the liquid ammonia is delivered to the main engine (11) for combustion through the valve group unit (10).

8. The ammonia fuel supply system according to claim 1, wherein ​ 9. The ammonia fuel supply system according to claim 8, characterized by ​ 10. The ammonia fuel supply system according to claim 1, wherein ​ 11. The ammonia fuel supply system according to claim 1, wherein ​ ​ ​ ​

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