A marine liquefied petroleum gas fuel supply system

Abstract

This invention relates to the field of marine engineering technology, and in particular to a marine liquefied petroleum gas (LPG) fuel supply system. The system includes an LPG storage tank, a refueling module, a low-pressure pump, a high-pressure pump, a heat exchanger, a valve assembly, an engine, a recirculation tank, a dual pressure relief system, and a nitrogen system. The refueling module achieves safe LPG refueling and gas-phase reflux through dual interfaces; the low-pressure and high-pressure pumps work together in the reflux pipeline to stabilize fuel pressure, and the water-glycol circulation system, in conjunction with the heat exchanger, precisely regulates fuel temperature; unconsumed fuel is recovered to the storage tank for recycling via the return valve assembly and recirculation tank; the dual independent pressure relief system, combined with a gas-liquid separator, intercepts liquid LPG, and the nitrogen system performs pipeline replacement and purging. This system solves the problems of unstable pressure, fuel waste, emission pollution, and insufficient safety protection inherent in traditional technologies. It provides stable fuel supply, high utilization rate, and is safe and environmentally friendly, meeting the operational requirements of marine LPG dual-fuel engines.

Description

Technical Field

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

[0002] As the International Maritime Organization (IMO) tightens its restrictions on sulfur oxide emissions from ships, liquefied petroleum gas (LPG), a net-zero sulfur emission fuel, is increasingly being used in marine fuels. Compared to traditional fuels, LPG as a marine fuel can almost completely eliminate sulfur oxide emissions while reducing carbon emissions by about 15%, offering significant environmental advantages. Therefore, more and more ships are adopting LPG dual-fuel engines.

[0003] To meet the requirements of LPG dual-fuel engines, ships need to be equipped with dedicated LPG fuel storage and supply systems. However, the inherent characteristics of LPG and the engine's stringent fuel supply requirements present numerous technical challenges to the system design.

[0004] On the one hand, LPG differs from traditional marine diesel fuel. It is a flammable, explosive, and volatile low-flash-point fuel, mainly composed of propane and butane (with a small amount of pentane added). Under ISO environmental conditions, it is a colorless gas with a density higher than air, and its explosion limit is 1.5% to 9.5%. When mixed with air, it is prone to combustion and explosion when exposed to open flames or high heat. This places extremely high demands on the safety design of LPG refueling, storage, transportation, and recycling on ships, requiring the system to be as safe as traditional fuel systems.

[0005] On the other hand, LPG dual-fuel engines have strict limitations on fuel supply parameters, requiring the LPG supply pressure to be stable within the range of 53 bar ± 2 bar and the supply temperature to be controlled between 25°C and 45°C. If the pressure or temperature parameters do not meet the above requirements, the engine will stop operating in LPG mode and switch to fuel mode, affecting the ship's environmental operating efficiency and navigation stability.

[0006] In addition, the storage form of LPG directly affects the space utilization efficiency on board: propane has a boiling point of -42℃, and it can be stored in liquid form in the ship's storage tank by lowering the temperature or applying pressure. Compared with gaseous storage, liquid storage can significantly improve space utilization, which also puts forward specific requirements for the storage structure design of the system.

[0007] In summary, there is a lack of existing technologies for a marine LPG fuel supply system that can meet the stringent supply parameter requirements of LPG dual-fuel engines while balancing storage efficiency and operational safety. Therefore, developing a marine liquefied petroleum gas fuel supply system that meets the above technical requirements is of great practical significance. Summary of the Invention

[0008] In view of this, the present invention provides a marine liquefied petroleum gas fuel supply system.

[0009] Therefore, the present invention provides the following technical solution:

[0010] A marine liquefied petroleum gas fuel supply system includes:

[0011] LPG storage tank, refueling module, low-pressure pump, high-pressure pump, heat exchanger, fuel supply valve group SVT, LPG dual-fuel engine, recirculation tank, water glycol circulation system, fuel return valve group RVT, first gas-liquid separator, first vent pipe, second gas-liquid separator, second vent pipe and nitrogen system, first pressure relief system and second pressure relief system;

[0012] The filling module is equipped with a liquid phase interface and a gas phase interface. One end of the liquid phase interface is connected to an external LPG source, and the other end is connected to the liquid phase inlet of the LPG storage tank. One end of the gas phase interface is connected to the gas phase outlet of the LPG storage tank, and the other end is connected to an external LPG source.

[0013] The LPG storage tank is equipped with a low-pressure pump. The outlet of the low-pressure pump is divided into two branches via pipelines: one branch is connected to the inlet of the high-pressure pump, and the other branch is connected to the LPG storage tank via a pipeline through a first adjustable valve.

[0014] The outlet of the high-pressure pump is divided into two pipelines: one is connected to the LPG inlet of the heat exchanger, and the other is connected to the LPG storage tank via a pipeline through a second adjustable valve.

[0015] The water outlet pipe of the water-ethylene glycol circulation system is connected to the heat medium inlet of the heat exchanger through the heat medium inlet pipe, and the water return pipe of the water-ethylene glycol circulation system is connected to the heat medium outlet of the heat exchanger through the heat medium outlet pipe. A third adjustable valve is connected in parallel between the heat medium inlet pipe and the heat medium outlet pipe of the heat exchanger.

[0016] The LPG outlet of the heat exchanger is connected to the inlet of the fuel supply valve group SVT, and the outlet of the fuel supply valve group SVT is connected to the fuel inlet of the LPG dual-fuel engine.

[0017] The inlet of the fuel return valve assembly (RVT) is connected to the fuel return port of the LPG dual-fuel engine, and the outlet is connected to the recirculation tank.

[0018] The recirculation tank is connected to the LPG storage tank via a fourth adjustable valve;

[0019] The nitrogen system is connected to the main pipeline inside the fuel supply valve group SVT.

[0020] The first pressure relief system is connected to the LPG storage tank and the recirculation tank; the second pressure relief system is connected to the main pipeline inside the fuel return valve group (RVT).

[0021] Furthermore, the first pressure relief system includes a first pressure monitoring device, a first pressure relief valve, a first gas-liquid separator, and a first vent pipe; both the LPG storage tank and the recirculation tank are equipped with a first pressure monitoring device and a first pressure relief valve, the inlet of the first pressure relief valve on the LPG storage tank is connected to the LPG storage tank, the inlet of the first pressure relief valve on the recirculation tank is connected to the recirculation tank, the outlets of both first pressure relief valves are connected to the first gas-liquid separator, and the outlet of the first gas-liquid separator is connected to the first vent pipe;

[0022] The second pressure relief system includes a second pressure monitoring device, a second pressure relief valve, a second gas-liquid separator, and a second vent pipe; the second pressure monitoring device and the second pressure relief valve are arranged on the main pipeline inside the fuel return valve group RVT. The inlet of the second pressure relief valve is connected to the main pipeline of the fuel return valve group RVT, the outlet of the second pressure relief valve is connected to the second gas-liquid separator, and the outlet of the second gas-liquid separator is connected to the second vent pipe.

[0023] Furthermore, it also includes a back pressure regulating valve, which is arranged in series on the pipeline between the fuel return valve assembly (RVT) and the recirculation tank.

[0024] Furthermore, it also includes a liquid level sensor, which is arranged inside the recirculation tank, and the signal output terminal of the liquid level sensor is electrically connected to the control terminal of the fourth adjustable valve.

[0025] Furthermore, it also includes an LPG flow meter, which is arranged in series on the pipeline between the LPG outlet of the heat exchanger and the inlet of the fuel supply valve assembly SVT.

[0026] Furthermore, the first adjustable valve, the second adjustable valve, the third adjustable valve, and the fourth adjustable valve are all frequency conversion regulating valves; the low-pressure pump is a submersible centrifugal pump; and the high-pressure pump is a gear pump or a plunger pump.

[0027] Furthermore, the heat transfer medium in the water-ethylene glycol circulation system is a mixed solution of water and ethylene glycol with a volume ratio of 50:50.

[0028] Furthermore, both the first gas-liquid separator and the second gas-liquid separator are equipped with a water mist collection device.

[0029] Furthermore, the fuel return valve assembly RVT is equipped with a level switch.

[0030] Advantages and positive effects of the present invention:

[0031] By arranging low-pressure and high-pressure pumps separately, and providing pipelines for returning to the LPG storage tank at both the low-pressure and high-pressure pump outlets, pressure fluctuations under different operating conditions are effectively offset, making the fuel supply more stable and solving the problem of unstable pressure in traditional pressurization systems.

[0032] By connecting the fuel return valve assembly, recirculation tank, and LPG storage tank in sequence, unconsumed LPG can be recycled and reused through this path, improving fuel utilization and solving the waste problem of direct emission of unconsumed fuel in traditional technologies.

[0033] By setting up independent first and second pressure relief systems, each equipped with a corresponding gas-liquid separator and vent pipe with a built-in water mist collection device, cross-contamination between different pressure relief channels is avoided during pressure relief. The water mist collection device intercepts liquid LPG in the emitted gas, preventing direct discharge of liquid phase and pollution of the deck and marine environment. This complies with ship pollution prevention regulations and solves the problem of direct discharge of liquid phase and environmental pollution in traditional technologies.

[0034] By connecting the nitrogen system with the fuel supply valve assembly, the air and residual LPG in the pipeline can be completely replaced during system start-up and shutdown, eliminating the risk of explosion caused by gas-liquid mixing; the independent setting of the dual pressure relief system can quickly respond to overpressure conditions and ensure that the system pressure is stable within a safe range, solving the problem of insufficient safety protection in traditional systems. Attached Figure Description

[0035] 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.

[0036] Figure 1 A schematic diagram of a marine liquefied petroleum gas fuel supply system provided by the present invention.

[0037] In the diagram: 001, LPG storage tank; 002, refueling module; 003, low-pressure pump; 004, recirculation tank; 005, high-pressure pump; 006, heat exchanger; 007, LPG flow meter; 008, fuel supply valve assembly (SVT); 009, LPG dual-fuel engine; 010, first gas-liquid separator; 011, fourth adjustable valve; 012, second gas-liquid separator; 013, water mist collection device; 014, nitrogen system; 015, water-glycol circulation system; 016, first adjustable valve; 017, back pressure regulating valve; 018, level sensor; 019, third adjustable valve; 020, second adjustable valve; 021, fuel return valve assembly (RVT); 022, level switch. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] This invention provides a marine liquefied petroleum gas fuel supply system, such as... Figure 1 As shown, it includes:

[0041] LPG storage tank 001, filling module 002, low-pressure pump 003, high-pressure pump 005, heat exchanger 006, fuel supply valve group SVT 008, LPG dual-fuel engine 009, recirculation tank 004, water glycol circulation system 015, fuel return valve group RVT 021, first gas-liquid separator 010, first vent pipe, second gas-liquid separator 012, second vent pipe and nitrogen system 014, first pressure relief system and second pressure relief system.

[0042] The filling module 002 is equipped with a liquid phase interface L and a gas phase interface V. One end of the liquid phase interface L is connected to an external LPG source, and the other end is connected to the liquid phase inlet of the LPG storage tank 001. One end of the gas phase interface V is connected to the gas phase outlet of the LPG storage tank 001, and the other end is connected to an external LPG source.

[0043] The LPG storage tank 001 is equipped with a low-pressure pump 003. The outlet of the low-pressure pump 003 is divided into two pipelines: one is connected to the inlet of the high-pressure pump 005, and the other is connected to the LPG storage tank 001 via the first adjustable valve 016.

[0044] The outlet of the high-pressure pump 005 is connected to two pipelines: one is connected to the LPG inlet of the heat exchanger 006, and the other is connected to the LPG storage tank 001 via the second adjustable valve 020.

[0045] The outlet pipe of the water-ethylene glycol circulation system 015 is connected to the heat medium inlet of heat exchanger 006 via the heat medium inlet pipe, and the return pipe of the water-ethylene glycol circulation system 015 is connected to the heat medium outlet of heat exchanger 006 via the heat medium outlet pipe. A third adjustable valve 019 is connected in parallel between the heat medium inlet pipe and the heat medium outlet pipe of heat exchanger 006. The heat medium in the water-ethylene glycol circulation system 015 is a mixed solution of water and ethylene glycol with a volume ratio of 50:50.

[0046] The first adjustable valve 016, the second adjustable valve 020, and the third adjustable valve 019 are all frequency conversion regulating valves; the low-pressure pump 003 is a submersible centrifugal pump; and the high-pressure pump 005 is a gear pump or a plunger pump.

[0047] The LPG outlet of heat exchanger 006 is connected to the inlet of fuel supply valve group SVT008, and the outlet of fuel supply valve group SVT008 is connected to the fuel inlet of LPG dual-fuel engine 009; it also includes LPG flow meter 007, which is arranged in series on the pipeline between the LPG outlet of heat exchanger 006 and the inlet of fuel supply valve group SVT008.

[0048] The inlet of the fuel return valve assembly RVT021 is connected to the fuel return port of the LPG dual-fuel engine 009, and the outlet is connected to the recirculation tank 004. It also includes a back pressure regulating valve 017, which is connected in series on the pipeline between the fuel return valve assembly RVT021 and the recirculation tank 004. A level switch 022 is installed inside the fuel return valve assembly RVT021.

[0049] The recirculation tank 004 is connected to the LPG storage tank 001 via the fourth adjustable valve 011; it also includes a level sensor 018, which is arranged inside the recirculation tank 004 and the signal output terminal of the level sensor 018 is electrically connected to the control terminal of the fourth adjustable valve 011.

[0050] The nitrogen system 014 is connected to the main pipeline inside the fuel supply valve group SVT008;

[0051] The first pressure relief system is connected to LPG storage tank 001 and recirculation tank 004; the second pressure relief system is connected to the main pipeline inside fuel return valve group RVT021.

[0052] The first pressure relief system includes a first pressure monitoring device, a first pressure relief valve, a first gas-liquid separator 010, and a first vent pipe; the first pressure monitoring device and the first pressure relief valve are arranged on both the LPG storage tank 001 and the recirculation tank 004. The inlet of the first pressure relief valve on the LPG storage tank 001 is connected to the LPG storage tank 001, and the inlet of the first pressure relief valve on the recirculation tank 004 is connected to the recirculation tank 004. The outlets of both first pressure relief valves are connected to the first gas-liquid separator 010, and the outlet of the first gas-liquid separator 010 is connected to the first vent pipe.

[0053] The second pressure relief system includes a second pressure monitoring device, a second pressure relief valve, a second gas-liquid separator 012, and a second vent pipe. The second pressure monitoring device and the second pressure relief valve are arranged on the main pipeline inside the fuel return valve assembly RVT021. The inlet of the second pressure relief valve is connected to the main pipeline of the fuel return valve assembly RVT021, and the outlet of the second pressure relief valve is connected to the second gas-liquid separator 012. The outlet of the second gas-liquid separator 012 is connected to the second vent pipe. Both the first gas-liquid separator 010 and the second gas-liquid separator 012 are equipped with water mist collection devices 013.

[0054] Working principle:

[0055] When a ship needs to refuel with LPG, an external LPG source is connected through the liquid phase interface L of the refueling module 002, and LPG is injected into the LPG storage tank 001 in liquid form. During the refueling process, the gas phase space inside the LPG storage tank 001 is compressed, and the pressure increases. The original gas inside the tank flows back to the external LPG source through the gas phase interface V of the refueling module 002, which maintains the pressure inside the tank and reduces LPG emissions. LPG is stored in the LPG storage tank 001 in liquid form. The LPG storage tanks can be of full pressure, cryogenic, or cryogenic full pressure type, and the number and installation position can be flexibly arranged according to the needs of the ship.

[0056] When the LPG dual-fuel engine 009 switches to LPG operation mode, the system starts the supply process: the low-pressure pump 003 in the LPG storage tank 001 runs first, extracts liquid LPG and initially pressurizes it before delivering it to the high-pressure pump 005; the redundant LPG output by the low-pressure pump 003 flows back to the LPG storage tank 001 through the first adjustable valve 016. The first adjustable valve 016 adjusts its opening according to the inlet pressure of the high-pressure pump 005 to ensure stable inlet pressure.

[0057] High-pressure pump 005, employing either a gear pump or a plunger pump, pressurizes LPG to the engine's required pressure of 53 bar ± 2 bar upon startup. Simultaneously, it adapts to the engine load and adjusts the supply flow rate via frequency conversion. During sudden changes in engine load, excess LPG output from high-pressure pump 005 flows back to LPG storage tank 001 through the second adjustable valve 020. The second adjustable valve 020 adjusts based on the outlet pressure of high-pressure pump 005 to maintain system pressure stability. The pressurized LPG enters heat exchanger 006, where a 50:50 volume ratio water-ethylene glycol mixture is supplied by the water-ethylene glycol circulation system 015 to heat the LPG. The third adjustable valve 019 adjusts its opening based on the LPG temperature at the outlet of heat exchanger 006, altering the flow rate of the heat medium through the heat exchanger and precisely controlling the LPG temperature within the engine-suitable range of 25℃-45℃.

[0058] After temperature and pressure regulation, the LPG flows through the LPG flow meter 007 to measure the quality of fuel supplied to the engine. The measured LPG is then delivered to the fuel inlet of the LPG dual-fuel engine 009 through the fuel supply valve group SVT008 to provide power for engine combustion.

[0059] LPG not fully consumed by the engine flows out through the fuel return valve assembly RVT021, is depressurized by the back pressure regulating valve 017, and then introduced into the recirculation tank 004. The liquid level sensor 018 in the recirculation tank 004 monitors the liquid level in real time. When the liquid level reaches a preset value, the liquid level sensor 018 sends a signal to control the fourth adjustable valve 011 to open, guiding the recovered LPG back to the LPG storage tank 001 for recycling. The liquid level switch 022 inside the fuel return valve assembly RVT021 monitors in real time whether there is any liquid residue in the pipeline, ensuring the stable operation of the recovery chain.

[0060] The first pressure monitoring device on LPG storage tank 001 and recirculation tank 004 monitors the tank pressure in real time. When the pressure is over-pressurized, it triggers the corresponding first pressure relief valve to introduce the gas into the first gas-liquid separator 010. The second pressure monitoring device in the fuel return valve group RVT021 monitors the pipeline pressure. When the pressure is over-pressurized, it triggers the second pressure relief valve to introduce the gas into the second gas-liquid separator 012. The water mist collection device 013 in the two gas-liquid separators intercepts the liquid phase LPG in the gas. The separated gas is safely discharged through its respective vent pipe to avoid pollution and cross-contamination risks.

[0061] Before the system starts, nitrogen system 014 introduces nitrogen into the main pipeline of fuel supply valve group SVT008 to replace the air and moisture in the pipeline; when the system stops running and is not restarted for a short time, nitrogen first blows the residual LPG in the pipeline into recirculation tank 004, and then blows the residual gas into gas-liquid separator to completely remove flammable and explosive media and eliminate safety hazards.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A marine liquefied petroleum gas fuel supply system, characterized in that, include: LPG storage tank (001), filling module (002), low-pressure pump (003), high-pressure pump (005), heat exchanger (006), fuel supply valve group SVT (008), LPG dual-fuel engine (009), recirculation tank (004), water glycol circulation system (015), fuel return valve group RVT (021), first gas-liquid separator (010), first vent pipe, second gas-liquid separator (012), second vent pipe and nitrogen system (014), first pressure relief system and second pressure relief system; The filling module (002) is provided with a liquid phase interface and a gas phase interface. One end of the liquid phase interface is connected to an external LPG source, and the other end is connected to the liquid phase inlet of the LPG storage tank (001). One end of the gas phase interface is connected to the gas phase outlet of the LPG storage tank (001), and the other end is connected to an external LPG source. The LPG storage tank (001) is equipped with a low-pressure pump (003). The outlet of the low-pressure pump (003) is divided into two paths through pipelines: one path is connected to the inlet of the high-pressure pump (005), and the other path is connected to the LPG storage tank (001) through the first adjustable valve (016) via pipeline. The outlet of the high-pressure pump (005) is set in two directions through pipelines: one direction is connected to the LPG inlet of the heat exchanger (006), and the other direction is connected to the LPG storage tank (001) through the pipeline via the second adjustable valve (020). The outlet pipe of the water-ethylene glycol circulation system (015) is connected to the heat medium inlet of the heat exchanger (006) through the heat medium inlet pipe, and the return pipe of the water-ethylene glycol circulation system (015) is connected to the heat medium outlet of the heat exchanger (006) through the heat medium outlet pipe. A third adjustable valve (019) is connected in parallel between the heat medium inlet pipe and the heat medium outlet pipe of the heat exchanger (006). The LPG outlet of the heat exchanger (006) is connected to the inlet of the fuel supply valve group SVT (008), and the outlet of the fuel supply valve group SVT (008) is connected to the fuel inlet of the LPG dual-fuel engine (009). The inlet of the fuel return valve assembly RVT (021) is connected to the fuel return port of the LPG dual-fuel engine (009), and the outlet is connected to the recirculation tank (004). The recirculation tank (004) is connected to the LPG storage tank (001) via a fourth adjustable valve (011); The nitrogen system (014) is connected to the main pipeline inside the fuel supply valve group SVT (008); The first pressure relief system is connected to the LPG storage tank (001) and the recirculation tank (004); the second pressure relief system is connected to the main pipeline inside the fuel return valve group RVT (021); The first pressure relief system includes a first pressure monitoring device, a first pressure relief valve, a first gas-liquid separator (010), and a first vent pipe; the LPG storage tank (001) and the recirculation tank (004) are each equipped with a first pressure monitoring device and a first pressure relief valve. The inlet of the first pressure relief valve on the LPG storage tank (001) is connected to the LPG storage tank (001), and the inlet of the first pressure relief valve on the recirculation tank (004) is connected to the recirculation tank (004). The outlets of both first pressure relief valves are connected to the first gas-liquid separator (010), and the outlet of the first gas-liquid separator (010) is connected to the first vent pipe. The second pressure relief system includes a second pressure monitoring device, a second pressure relief valve, a second gas-liquid separator (012), and a second vent pipe; the second pressure monitoring device and the second pressure relief valve are arranged on the main pipeline inside the fuel return valve group RVT (021), the inlet of the second pressure relief valve is connected to the main pipeline of the fuel return valve group RVT (021), the outlet of the second pressure relief valve is connected to the second gas-liquid separator (012), and the outlet of the second gas-liquid separator (012) is connected to the second vent pipe; Both the first gas-liquid separator (010) and the second gas-liquid separator (012) are equipped with a water mist collection device (013).

2. A marine liquefied petroleum gas fuel supply system according to claim 1, characterized in that, It also includes a back pressure regulating valve (017), which is arranged in series on the pipeline between the fuel return valve group RVT (021) and the recirculation tank (004).

3. A marine liquefied petroleum gas fuel supply system according to claim 1, characterized in that, It also includes a level sensor (018), which is arranged inside the recirculation tank (004), and the signal output terminal of the level sensor (018) is electrically connected to the control terminal of the fourth adjustable valve (011).

4. A marine liquefied petroleum gas fuel supply system according to claim 1, characterized in that, It also includes an LPG flow meter (007), which is arranged in series on the pipeline between the LPG outlet of the heat exchanger (006) and the inlet of the fuel supply valve assembly SVT (008).

5. A marine liquefied petroleum gas fuel supply system according to claim 1, characterized in that, The first adjustable valve (016), the second adjustable valve (020), the third adjustable valve (019) and the fourth adjustable valve (011) are all frequency conversion regulating valves; the low-pressure pump (003) is a submersible centrifugal pump; the high-pressure pump (005) is a gear pump or a plunger pump.

6. A marine liquefied petroleum gas fuel supply system according to claim 1, characterized in that, The heat transfer medium in the water-ethylene glycol circulation system (015) is a mixed solution of water and ethylene glycol with a volume ratio of 50:

50.

7. A marine liquefied petroleum gas fuel supply system according to claim 1, characterized in that, The fuel return valve assembly RVT (021) is equipped with a level switch (022).

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