Fuel gas supply system suitable for LEG diesel engine

Abstract

The invention discloses a fuel gas supply system suitable for an LEG diesel engine. The fuel gas supply system comprises an air temperature gasifier, an LEG fuel storage tank, a low-pressure immersed pump, a filter, a high-pressure fuel pump, a high-temperature heat exchanger and a valve group control unit. According to the system, tank car pressurization is achieved through the air temperature vaporizer, liquid ethane is stored in the storage tank, then pressurized and conveyed through the low-pressure immersed pump, the filter and the high-pressure fuel pump in sequence and finally gasified into high-pressure fuel gas in the high-temperature heat exchanger, and the high-pressure fuel gas is supplied to a diesel engine through the valve set control unit. The system adopts the design of a double-layer vacuum heat insulation storage tank and a heat preservation pipeline, pressure and temperature sensors are arranged for real-time monitoring, and stable pressure control is achieved through a bypass backflow pipeline and frequency conversion adjustment. The technical problems of low-temperature storage, high-pressure gasification and long-distance conveying of LEG fuel are solved, and the system has the advantages of being stable in gas supply, safe, reliable, energy-saving, environment-friendly and the like, and is suitable for clean energy transformation of ships and land diesel engines.

Description

Technical Field

[0001] This invention relates to the field of marine propulsion systems and clean energy application technology, specifically to a gas supply system suitable for LEG (liquefied ethane) diesel engines. This system optimizes fuel storage, transportation, and gasification processes to provide a stable supply of high-pressure ethane gas to dual-fuel diesel engines, enabling partial replacement of traditional diesel fuel with clean energy. It is applicable to energy-saving and emission-reduction retrofits of marine and land-based diesel engines. Background Technology

[0002] Against the backdrop of the current global energy transition and increasingly stringent environmental requirements, traditional diesel engines face severe challenges due to their high emissions (such as sulfur oxides, nitrogen oxides, and particulate matter). Liquefied natural gas (LNG), as a transitional clean energy source, has been widely used, but its supply chain and infrastructure constraints have prompted the industry to explore alternatives. Liquefied ethane gas (LEG), as a high-calorific-value clean energy source, has gradually gained more attention. From the perspectives of acquisition methods, transportation, storage, and economic development, it is widely accepted as a supplement or alternative to LNG, thereby better supporting the transformation of maritime transport and partially replacing the use of gasoline or diesel.

[0003] However, the cryogenic storage (-88°C) and high-pressure gasification characteristics of LEG place special demands on the fuel supply system:

[0004] Storage and vaporization: LEG needs to be kept in a liquid state in an insulated storage tank, and efficient heat exchange is required during vaporization to avoid temperature fluctuations affecting engine performance.

[0005] Transportation safety: Long-distance pipeline transportation requires addressing insulation and pressure stability issues to prevent gas phase change or temperature loss.

[0006] System flexibility: It needs to support multi-tank switching, redundancy design and dynamic pressure regulation to adapt to the complex operating conditions of ships.

[0007] Existing fuel oil or LNG supply systems are insufficient to meet these requirements, particularly in terms of high-pressure vaporization and precise temperature control. Therefore, there is an urgent need for a dedicated gas supply system for LEG diesel engines, integrating cryogenic storage, high-pressure pumping, staged heating, and intelligent control functions to ensure stable gas supply and improve energy efficiency. Summary of the Invention

[0008] The purpose of this invention is to provide a gas supply system suitable for LEG diesel engines for dual-fuel diesel engines, aiming to solve the technical problems of low temperature preservation, pressure stability and system flexibility in the storage, transportation and gasification process of LEG fuel in the prior art, so as to meet the stable and continuous operation of diesel engines under specific conditions and realize the partial replacement of diesel by clean energy.

[0009] The technical solution adopted by the present invention to solve the above problems is as follows:

[0010] A gas supply system for LEG diesel engines, characterized in that it includes:

[0011] The ambient temperature vaporizer is connected to the tank truck through gas phase pipelines and liquid phase pipelines. It is used to initially vaporize the liquid ethane transported by the tank truck to pressurize the tank truck.

[0012] Two LEG fuel storage tanks are connected in parallel to an ambient air vaporizer via liquid phase pipelines;

[0013] A low-pressure submersible pump is connected to the liquid phase outlet of the LEG fuel storage tank via a first vacuum-insulated pipe.

[0014] The filter's inlet is connected to the outlet of the low-pressure submersible pump.

[0015] A high-pressure fuel pump, with its input end connected to the output end of the filter;

[0016] The high-temperature heat exchanger has its inlet connected to the outlet of the high-pressure fuel pump.

[0017] The valve group control unit is connected to the output end of the high-temperature heat exchanger via insulated pipes;

[0018] The LEG fuel storage tank adopts a double-layer vacuum insulation structure and is equipped with a top spray filling port and a bottom filling port. A tank switching valve is provided between the two storage tanks.

[0019] Furthermore, both the low-pressure submersible pump and the high-pressure fuel pump are equipped with bypass return pipes at their outlets. These bypass return pipes are connected to the liquid phase inlet of the LEG fuel storage tank to regulate system pressure and flow rate.

[0020] Furthermore, the high-temperature heat exchanger is connected to a water-glycol circulation system.

[0021] Furthermore, the air-temperature vaporizer is used to pressurize the tanker through gas phase and liquid phase pipelines, and then the fuel is injected into the LEG storage tank through the liquid phase pipeline. The fuel flows into the low-pressure submersible pump through the vacuum insulated pipeline by its own gravity. After being pressurized, it flows through the filter and is stably delivered to the high-pressure pump. After the pressure is regulated by frequency conversion, it is stably delivered to the high-temperature vaporizer. After absorbing the heat of water glycol, it is vaporized into high-pressure ethane gas. The high-pressure gas is then delivered to the valve unit outside the workshop through a long-distance gas supply pipeline.

[0022] The test run operator controls the valve unit according to the commands of the diesel engine to determine when and how the gas enters and stops entering the diesel engine's gas pipeline.

[0023] The system has two LEG fuel storage tanks, each with two filling modes: top filling and bottom filling. Top filling is a spray injection method. During use, single or double tanks can be used, and tank switching can also be achieved to ensure the stability of the system's liquid supply.

[0024] The liquid phase pipeline, gas phase pipeline, and liquid phase pipeline are all insulated against cold, and the gas transmission pipeline is insulated. Pressure sensors and temperature sensors are installed in the pipeline as needed to detect the pressure and temperature of fuel at different points to ensure safe and stable gas supply.

[0025] Due to its special structure, the LEG fuel storage tank has excellent cold insulation properties. In engineering applications, it can achieve single-tank and dual-tank liquid supply, and can also realize tank switching function to ensure the stability of the system liquid supply.

[0026] All fuel filling pipelines are insulated to reduce the cold loss of LEG during filling, and the insulation covers prevent operators from getting frostbite from contact with low-temperature liquids; the protection and gas delivery pipelines are insulated to ensure that the gas temperature does not drop significantly as it travels through long pipelines, thus meeting the diesel engine's temperature requirements for gas.

[0027] Pressure and temperature sensors are installed in the pipeline to detect the pressure and temperature at the corresponding locations, ensuring the safety and stability of the gas supply process.

[0028] Both the low-pressure submersible pump and the high-pressure pump are equipped with bypass return lines at their outlets to send a portion of the pumped LEG back to the storage tank, thereby balancing the pressure and flow required for the liquid supply.

[0029] The heat source for LEG is divided into two stages, as follows: Hot water, heated by electric heating, is pumped to a heat exchanger to raise the temperature of water-glycol to the required level. The heated water-glycol then enters a high-temperature vaporizer to transfer heat to the LEG, causing it to absorb heat and change into a gaseous state. Two pumps are provided for both the hot water circulation pump and the water-glycol pump; under normal circumstances, one is in operation and the other is on standby to ensure the stability of the system heating.

[0030] The working principle of this invention is as follows:

[0031] Fueling phase:

[0032] The tank truck transports liquid ethane to the ambient temperature vaporizer via a liquid phase pipeline. The vaporized ethane is then returned to the tank truck via a gas phase pipeline, thus pressurizing the tank truck.

[0033] The pressurized liquid ethane is injected into the storage tank through a liquid phase pipeline, and either top spray injection or bottom injection mode can be selected.

[0034] Fuel delivery phase:

[0035] Liquid ethane in the storage tank flows into the low-pressure submersible pump by gravity, and after initial pressurization, it passes through a filter and enters the high-pressure fuel pump.

[0036] A high-pressure fuel pump pressurizes liquid ethane to the required pressure and vaporizes it into high-pressure fuel gas through a high-temperature heat exchanger.

[0037] The high-pressure gas after vaporization is delivered to the diesel engine through the valve group control unit.

[0038] Pressure and temperature regulation:

[0039] The bypass return lines (sixth and seventh lines) for the low-pressure submersible pump and the high-pressure fuel pump can regulate system pressure and flow.

[0040] The water-glycol circulation system provides a stable heat source for the high-temperature heat exchanger, ensuring a constant temperature during the gasification process.

[0041] Pressure and temperature sensors installed in the pipeline monitor the system status in real time to ensure safe operation.

[0042] Compared with the prior art, the advantages of the present invention are:

[0043] The double-walled vacuum insulated storage tank provides a guarantee for the cryogenic storage of LEG, and the different usage methods of single tank, double tank and inverted tank improve the stability and reliability of system operation.

[0044] Using ethane gas as diesel engine fuel, replacing traditional diesel, or as a substitute for liquefied natural gas, has significant energy-saving and emission-reduction effects. It not only promotes environmental protection but also helps improve ship energy efficiency.

[0045] The fuel supply system can stably deliver fuel gas in specific conditions to the diesel engine, ensuring its stable and continuous operation and guaranteeing the various navigation needs of LEG fuel-powered vessels.

[0046] The fuel system has a simple structure, is easy to operate, requires few devices and is easy to maintain, making it suitable for widespread use on land and ships. Attached Figure Description

[0047] Figure 1 A schematic diagram of a gas supply system suitable for LEG diesel engines.

[0048] Wherein: L1 - Liquid phase injection pipeline, L2 - Gas phase injection pipeline, L3 - Liquid phase injection pipeline, 1 - Ambient air vaporizer, 2 and 3 - LEG fuel tanks, 4 - Low-pressure submersible pump, 5 - Filter, 6 - High-pressure pump, 7 - High-temperature vaporizer, 8 - Valve assembly unit Detailed Implementation

[0049] The following detailed description of a gas supply system for LEG diesel engines according to the present invention, with reference to the accompanying drawings and specific embodiments, will be further elaborated.

[0050] like Figure 1 As shown, a gas supply system suitable for LEG diesel engines includes an ambient air vaporizer 1, dual LEG fuel tanks 2 and 3, a low-pressure submersible pump 4, a filter 5, a high-pressure fuel pump 6, and a high-temperature heat exchanger 7.

[0051] After pressurizing the tank truck using the ambient temperature vaporizer (1), liquid phase injection pipeline L3 and gas phase injection pipeline L2, the liquid phase injection pipeline L1 is used to inject the liquid into the storage tank. The injection can be divided into top injection and bottom injection, with top injection being a spray injection.

[0052] After refueling, the fuel in the LEG tank flows under its own weight through a vacuum double-walled pipe into the low-pressure submersible pump. After being pressurized, it flows through a filter and is stably delivered to the high-pressure pump. Through frequency converter regulation, the pressure is regulated and the fuel is stably delivered to the high-temperature carburetor. There, it absorbs heat from the water glycol (heated by hot water) and vaporizes into high-pressure ethane gas. This high-pressure gas is then transported through a long-distance gas supply pipeline to the valve unit outside the workshop. The test run operators control the valve unit according to commands from the diesel engine to determine when and how much gas enters and exits the diesel engine's gas pipeline.

[0053] Both the low-pressure submersible pump and the high-pressure pump are equipped with bypass return lines at their outlets to send a portion of the pumped LEG back to the storage tank, thereby balancing the pressure and flow required for the liquid supply.

[0054] In the heating module, two hot water circulation pumps and two water glycol pumps are installed. Under normal circumstances, one is used and the other is on standby.

[0055] All fuel filling pipelines are insulated to reduce the loss of cold energy from the LEG during filling, and the insulation covers prevent operators from getting frostbite from contact with the low-temperature liquid; the protection and gas transmission pipelines are also insulated.

[0056] Pressure and temperature sensors are installed in the pipeline to detect the pressure and temperature at the corresponding locations, ensuring the safety and stability of the gas supply process.

Claims

1. A gas supply system suitable for LEG diesel engines, characterized in that, include: The ambient temperature vaporizer (1) is connected to the tank truck through the gas phase pipeline (L2) and the liquid phase pipeline (L3) to initially vaporize the liquid ethane transported by the tank truck and pressurize the tank truck. Two LEG fuel storage tanks (2, 3) are connected in parallel to an ambient air vaporizer (1) via a liquid phase pipeline (L1); The low-pressure submersible pump (4) is connected to the liquid phase outlet of the LEG fuel storage tank (2, 3) through the first vacuum insulated pipe; The filter (5) is connected at its input end to the output end of the low-pressure submersible pump (4); The input end of the high-pressure fuel pump (6) is connected to the output end of the filter (5); The high-temperature heat exchanger (7) is connected at its input end to the output end of the high-pressure fuel pump (6); The valve group control unit (8) is connected to the output end of the high-temperature heat exchanger (7) through an insulated pipe; The LEG fuel storage tanks (2 and 3) adopt a double-layer vacuum insulation structure and are equipped with a top spray filling port and a bottom filling port. A tank switching valve is provided between the two storage tanks.

2. The gas supply system for LEG diesel engines according to claim 1, characterized in that, The outlets of the low-pressure submersible pump (4) and the high-pressure fuel pump (6) are equipped with bypass return pipes, which are respectively connected to the liquid phase inlet of the LEG fuel storage tanks (2, 3) for regulating system pressure and flow rate.

3. The gas supply system for LEG diesel engines according to claim 1, characterized in that, The high-temperature heat exchanger (7) is connected to a water-glycol circulation system.

4. The gas supply system for LEG diesel engines according to claim 1, characterized in that, Using an ambient temperature vaporizer (1), the tank truck is pressurized through a gas phase pipeline (L2) and a liquid phase pipeline (L3), and then fuel is injected into the LEG storage tanks (2, 3) through a liquid phase pipeline (L1). The fuel flows into the low-pressure submersible pump (4) through a vacuum insulated pipeline by its own gravity. After being pressurized, it flows through a filter (5) and is stably delivered to the high-pressure pump (6). After being pressure-regulated by frequency conversion, it is stably delivered to the high-temperature vaporizer (7). After absorbing the heat of water glycol, it is vaporized into high-pressure ethane gas. The high-pressure gas is then delivered to the valve group unit (8) outside the workshop through a long-distance gas supply pipeline.

5. The gas supply system for LEG diesel engines according to claim 1, characterized in that, The test run operator controls the valve unit according to the commands of the diesel engine to determine when and how the gas enters and stops entering the diesel engine's gas pipeline.

6. A gas supply system for a LEG diesel engine according to claim 1, characterized in that, The system has two LEG fuel storage tanks, each with two filling modes: top filling and bottom filling. Top filling is a spray injection method. During use, single or double tanks can be used, and tank switching can also be achieved to ensure the stability of the system's liquid supply.

7. A gas supply system for a LEG diesel engine according to claim 1, characterized in that, The liquid phase pipeline (L1), gas phase pipeline (L2), and liquid phase pipeline (L3) are all insulated against cold, and the gas transmission pipeline is insulated. Pressure sensors and temperature sensors are installed in the pipelines as needed to detect the pressure and temperature of fuel at different points to ensure safe and stable gas supply.

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