Ship fuel supply system

Abstract

This invention provides a ship fuel supply system, comprising two fuel tanks, a fuel pump assembly, a BOG compressor, fuel equipment, a balance control module, a fuel filling inlet pipeline, and a fuel filling return gas pipeline. The fuel pump assembly includes low-pressure fuel pumps respectively installed in the two fuel tanks. The fuel filling inlet pipelines are connected to the two fuel tanks via liquid phase filling valves, and the fuel filling return gas pipelines are connected to the two fuel tanks via return gas valves. The balance control module is electrically connected to the low-pressure fuel pumps, BOG compressor, liquid phase filling valves, and return gas valves to control the ship fuel supply system to perform different actions. This ship fuel supply system can automatically regulate the liquid level and pressure differences between the two fuel tanks during fuel filling and supply to maintain stability, reducing or eliminating the need for manual operation and control, alleviating the burden on the crew, improving the system's ability to respond to emergencies, and enhancing system stability.

Description

Technical Field

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

[0002] During the operation of a ship's fuel supply system, the switching of moving equipment (i.e., rotating equipment driven by a propulsion engine, i.e., equipment that consumes energy, such as pumps, compressors, and fans) involves complex situations, mainly including the following usage scenarios:

[0003] I. Ship fuel supply systems typically employ two independent fuel tanks, symmetrically arranged on the port and starboard sides of the vessel. The system selects one fuel tank to supply fuel to subsequent pressurization and heat exchange equipment, ultimately supplying fuel to fuel systems such as the main engine and boilers. When the fuel level in one tank differs significantly from the other, it can affect the ship's load balance. In such cases, the system needs to switch the supply process from the lower-level tank to the higher-level tank. This process is mostly manual, involving the operator stopping the fuel supply pump and valves in one tank and then opening the fuel supply pump and valves in the other tank.

[0004] Furthermore, abnormal conditions such as insulation failure in a single fuel tank can also cause significant pressure differences between the two fuel tanks. These pressure differences primarily affect the stability of the fuel pump or compressor's supply pressure during the switching process: when switching fuel supply from one fuel tank to another, a large pressure difference between the tanks can cause excessively different inlet pressures for the BOG compressor and low-pressure fuel pump compared to before the switch, easily leading to fuel supply pressure fluctuations during the switching process. In this case, it is necessary to manually activate the BOG process for the corresponding fuel tank or open the appropriate balancing pipeline to ensure that the pressures of the two fuel tanks remain relatively balanced.

[0005] The manual switching process can cause fluctuations in fuel supply pressure. If the operation is not done properly, it can cause supply temperature or pressure alarms, triggering the control or safety system, cutting off the supply process, and switching the ship's engine to fuel mode.

[0006] II. Marine fuel supply systems are typically equipped with backup powered equipment, such as two low-pressure fuel pumps, two high-pressure fuel pumps, two BOG compressors, and two water / glycol pumps. In actual operation, only one of these devices operates, while the other remains in standby. If one device experiences a fault alarm, triggers a control system malfunction, or a safety system malfunction, the system first switches to the backup device. This process is mostly automatic, but uses only delayed-start control logic; that is, the system switches to the backup device after detecting a sustained low-low / high-high pressure alarm for a certain period. If the switching process occurs under high load on the supply system, it may still cause fluctuations in system temperature or pressure parameters, potentially triggering alarms in severe cases.

[0007] III. Marine fuel supply systems encompass various operating conditions, generally including: fuel pump supply, compressor supply, and combined fuel pump and compressor supply. Switching between these conditions involves switching of moving equipment, such as from fuel pump supply to combined fuel pump and compressor supply, from compressor supply to combined fuel pump and compressor supply, from combined fuel pump and compressor supply back to fuel pump supply, and from combined fuel pump and compressor supply back to compressor supply. Close monitoring of supply pressure changes is crucial during these transitions; improper control can lead to low or high pressure risks.

[0008] In view of this, it is necessary to design a ship fuel supply system that can automatically maintain the balance of fuel tank level and pressure, the balance of equipment usage time, and ensure the stable operation of the supply system during equipment switching. Summary of the Invention

[0009] The purpose of this invention is to provide a ship fuel supply system that can automatically regulate the liquid level difference and pressure difference between the two fuel tanks during fuel filling and fuel supply to maintain stability, reduce or avoid the original manual operation and control, reduce the burden on the crew, and improve the system's ability to cope with emergencies and improve the system's stability.

[0010] This invention provides a ship fuel supply system, comprising two fuel tanks, a fuel pump assembly, a BOG compressor, a fuel equipment, a balance control module, a fuel filling inlet pipeline, and a fuel filling return gas pipeline. The two fuel tanks are located on the port and starboard sides of the ship. The fuel pump assembly includes low-pressure fuel pumps respectively installed in the two fuel tanks, each connected to the fuel equipment to supply liquid fuel from the fuel tanks to the fuel equipment. The BOG compressor is connected to both fuel tanks and the fuel equipment to supply fuel vapors from the fuel tanks to the fuel equipment. The fuel filling inlet pipeline is connected to the fuel filling ports of the two fuel tanks via liquid phase filling valves, and the fuel filling return gas pipeline is connected to the return gas ports of the two fuel tanks via return gas valves. The balance control module is electrically connected to the low-pressure fuel pumps, the BOG compressor, the liquid phase filling valves, and the return gas valves, and is used to control the ship fuel supply system to perform the following actions:

[0011] Action 1: When the ship's fuel supply system is in refueling mode, if the liquid level difference between the two fuel tanks exceeds a preset value, the balance control module controls the liquid phase refueling valve and return gas valve of the fuel tank with the higher liquid level to close, so that the fuel refueling inlet pipeline only refuels the fuel tank with the lower liquid level; when the liquid level difference between the two fuel tanks is less than the preset value, the balance control module controls the closed liquid phase refueling valve and return gas valve to reopen;

[0012] Action 2: When the ship's fuel supply system is in supply mode, if the liquid level difference between the two fuel tanks exceeds a preset value, the balance control module controls the low-pressure fuel pump in the fuel tank with the low liquid level to uniformly reduce its operating frequency until the low-pressure fuel pump in the fuel tank with the low liquid level stops operating; at the same time, it controls the low-pressure fuel pump in the fuel tank with the high liquid level to start, and the initial operating frequency of the low-pressure fuel pump in the fuel tank with the high liquid level is the operating frequency of the low-pressure fuel pump in the fuel tank with the low liquid level before the switch.

[0013] Action 3: When the ship's fuel supply system is in refueling mode, if the pressure difference between the two fuel tanks exceeds a set value, the balance control module controls the return air valve of the high-pressure fuel tank to open and controls the return air valve of the low-pressure fuel tank to close; when the pressure difference between the two fuel tanks is less than the set value, the closed return air valve is controlled to reopen.

[0014] Action 4: When the ship's fuel supply system is in supply mode, if the pressure difference between the two fuel tanks exceeds a set value, and the fuel equipment is in a high-load supply condition with a load greater than or equal to 50%, the balance control module controls the BOG compressor to start to process the fuel vapor gas in the high-pressure fuel tank; when the pressure difference between the two fuel tanks is less than the set value, the BOG compressor is then controlled to shut down.

[0015] If the pressure difference between the two fuel tanks exceeds the set value, and the fuel equipment is in a low-load supply condition with a load of less than 50%, the balance control module controls the return gas valves of both fuel tanks to open, so that the two fuel tanks are connected through the fuel filling return gas pipeline; when the pressure difference between the two fuel tanks is less than the set value, the return gas valves of the two fuel tanks are then controlled to close.

[0016] Under high-load supply conditions, the fuel supply from the BOG compressor is relatively small compared to the total fuel supply, thus having minimal impact on the pump supply process (i.e., fuel is mainly supplied by the low-pressure fuel pump; after the BOG compressor starts, the low-pressure fuel pump only needs slight adjustments to its operating frequency to ensure stable fuel supply pressure and flow). Therefore, the BOG compressor is used to exhaust gas from the high-pressure fuel tank. However, under low-load supply conditions, the fuel supply from the BOG compressor is relatively large compared to the total fuel supply, thus having a greater impact on the pump supply process (at this time, the low-pressure fuel pump needs to significantly adjust its operating frequency to ensure stable fuel supply pressure and flow). Therefore, pressure balancing through gas exchange between the fuel tanks is chosen in this case.

[0017] Furthermore, each of the fuel tanks is equipped with two low-pressure fuel pumps connected in parallel; when the balance control module controls the ship's fuel supply system to perform the above-mentioned action two, the balance control module controls the low-pressure fuel pump in the fuel tank with a high liquid level to start, which has a shorter running time, thereby reducing the difference in running time between the low-pressure fuel pumps and extending the service life of the equipment.

[0018] Furthermore, each of the fuel tanks is equipped with two low-pressure fuel pumps connected in parallel; the balance control module is also used to control the ship's fuel supply system to perform the following actions:

[0019] Action 5: When the ship's fuel supply system is in supply mode, if the low-pressure fuel pump in the currently used fuel tank fails, the balance control module will prioritize controlling the other low-pressure fuel pump in the currently used fuel tank to start; if the other low-pressure fuel pump in the currently used fuel tank fails to start normally, the balance control module will control the other low-pressure fuel pump in the fuel tank with less running time to start.

[0020] Furthermore, the number of BOG compressors is two, and the two BOG compressors are connected in parallel; the balance control module is also used to control the ship's fuel supply system to perform the following actions:

[0021] Action 6: When one of the BOG compressors fails during operation, the balance control module controls the other BOG compressor to start.

[0022] Furthermore, when the balance control module controls the ship's fuel supply system to perform the above-mentioned action four, the balance control module prioritizes controlling the BOG compressor, which has a shorter operating time, to start.

[0023] Furthermore, when the ship's fuel supply system is in a fuel pump and compressor co-supply mode, if the BOG compressor fails, the balance control module controls the other BOG compressor to start, and at the same time controls the low-pressure fuel pump to increase its operating frequency for a period of time; after the other BOG compressor starts successfully, the balance control module controls the low-pressure fuel pump to restore its operating frequency, thereby reducing the impact of fuel supply pressure and supply flow during the switching process.

[0024] Furthermore, a high-pressure fuel pump is also provided between the low-pressure fuel pumps in the two fuel tanks and the fuel equipment, and the balance control module is electrically connected to the high-pressure fuel pump; there are two high-pressure fuel pumps, which are connected in parallel; the balance control module is also used to control the ship's fuel supply system to perform the following actions:

[0025] Action 7: When one of the high-pressure fuel pumps fails during operation, the balance control module controls the other high-pressure fuel pump to start.

[0026] Furthermore, the ship fuel supply system also includes a first heat exchange system. A fuel heating device is provided between the low-pressure fuel pumps in the two fuel tanks and the fuel equipment. The first heat exchange system is connected to the fuel heating device and is used to heat the fuel heating device. The first heat exchange system includes a heat source pipeline, a first circulation pump for circulating and transporting the heat exchange medium, and a heater for exchanging heat with the heat source. A heat source regulating valve is provided on the heat source pipeline. The first circulation pump is connected to both the fuel heating device and the heater. The heater is connected to both the fuel heating device and the heat source pipeline.

[0027] If the heat exchange medium is, for example, water / ethylene glycol, then the first circulation pump is a water / ethylene glycol pump, and the heater is a water / ethylene glycol heater. During operation, the heat exchange medium circulates between the first circulation pump, the heater, and the fuel heating equipment. The power for the circulation of the heat exchange medium comes from the first circulation pump. The heat exchange medium can exchange heat with the heat source (e.g., hot water in the cylinder liner) in the heater, thereby heating the heat exchange medium. After being heated, the heat exchange medium exchanges heat with the low-temperature fuel in the fuel heating equipment, thereby heating the low-temperature fuel to meet the supply temperature of the fuel equipment.

[0028] The balance control module is electrically connected to both the first circulating pump and the heat source regulating valve; there are two first circulating pumps, which are connected in parallel; the balance control module is also used to control the ship's fuel supply system to perform the following actions:

[0029] Action 8: When one of the first circulation pumps fails during operation, the balance control module controls the heat source regulating valve on the heat source pipeline to increase its opening and controls the other first circulation pump to start. After the other first circulation pump starts successfully, the opening of the heat source regulating valve is adjusted again. Since the switching process of the first circulation pump will cause fluctuations in the circulation flow of the heat exchange medium, increasing the flow rate of the heat source will increase the temperature of the heat exchange medium in a short period of time to offset the insufficient heat caused by the reduction in the flow rate of the heat exchange medium during the switching process, ensuring that the fuel supply temperature fluctuations meet the requirements of the fuel equipment.

[0030] Furthermore, there are two heaters and two heat source pipelines. The two heaters are connected in series and are connected to two heat source pipelines respectively. When the balance control module controls the ship's fuel supply system to perform the above-mentioned action eight, if one of the first circulation pumps fails during operation, the balance control module can also control the heat source regulating valve on the backup heat source pipeline to open, that is, use both heaters to heat the heat exchange medium simultaneously, thereby increasing the temperature of the heat exchange medium in a short period of time and reducing temperature fluctuations.

[0031] Furthermore, the fuel equipment includes high-pressure fuel equipment and low-pressure fuel equipment. The high-pressure fuel equipment can be the ship's main engine, and the low-pressure fuel equipment can be the ship's engine, ship's boiler, etc. The fuel heating equipment includes a high-pressure vaporizer and a low-pressure vaporizer. The high-pressure fuel pump and high-pressure vaporizer are located between the low-pressure fuel pump and the high-pressure fuel equipment, and the low-pressure vaporizer is located between the low-pressure fuel pump and the low-pressure fuel equipment. The BOG compressor is connected to the low-pressure fuel equipment to supply fuel to it. The fuel can be LNG, and the high-pressure vaporizer can vaporize LNG into natural gas. The first heat exchange system is connected to both the high-pressure vaporizer and the low-pressure vaporizer to heat them.

[0032] Furthermore, the ship fuel supply system also includes a second heat exchange system. A BOG preheater is provided between the BOG compressor and the two fuel tanks, and a BOG cooler is provided between the BOG compressor and the fuel equipment. The second heat exchange system is connected to both the BOG preheater and the BOG cooler, and is used to heat the BOG preheater and cool the BOG cooler. The second heat exchange system includes a cold source pipeline, a second circulation pump for circulating the heat exchange medium, and a heat exchange medium cooler for exchanging heat with the cold source. A cold source regulating valve is provided on the cold source pipeline. The second circulation pump is connected to the BOG preheater, the BOG cooler, and the heat exchange medium cooler, and the heat exchange medium cooler is connected to the cold source pipeline, the BOG preheater, and the BOG cooler.

[0033] If the heat exchange medium is, for example, water / ethylene glycol, then the second circulation pump is a water / ethylene glycol pump, and the heat exchange medium cooler is a water / ethylene glycol heater. During operation, the heat exchange medium circulates between the second circulation pump, the heat exchange medium cooler, and the BOG cooler, and also circulates between the second circulation pump, the heat exchange medium cooler, and the BOG preheater. The heat exchange medium can exchange heat with the cold source in the cold source pipeline within the heat exchange medium cooler, thereby cooling the heat exchange medium. After cooling, the heat exchange medium exchanges heat with the low-temperature BOG in the BOG preheater, thereby raising the temperature of the low-temperature BOG (because the temperature of the low-temperature BOG is very low, the temperature of the heat exchange medium must be higher than the temperature of the low-temperature BOG, thus enabling heat exchange and raising the temperature of the low-temperature BOG); the cooled heat exchange medium also exchanges heat with the high-temperature BOG in the BOG cooler, thereby cooling the high-temperature BOG.

[0034] The balance control module is electrically connected to the second circulation pump and the cold source regulating valve respectively; there are two second circulation pumps, which are connected in parallel; the balance control module is also used to control the ship's fuel supply system to perform the following actions:

[0035] Action Nine: When one of the second circulation pumps fails during operation, the balance control module controls the cold source regulating valve on the cold source pipeline to increase its opening and controls the other second circulation pump to start. After the other second circulation pump starts successfully, the opening of the cold source regulating valve is adjusted again. Since the switching process of the second circulation pump will cause fluctuations in the circulation flow of the heat exchange medium (the circulation flow of the heat exchange medium will temporarily decrease), the flow of the cold source is increased to offset the insufficient cooling caused by the decrease in the flow of the heat exchange medium during the switching process, thereby ensuring that the supply temperature fluctuation of the BOG meets the requirements of the fuel equipment.

[0036] Furthermore, the ship's fuel supply system has a fuel pump supply mode, a compressor supply mode, and a combined fuel pump and compressor supply mode. There are two BOG compressors, which are connected in parallel. The balance control module is also used to control the ship's fuel supply system to perform the following actions:

[0037] Action 10: When the ship's fuel supply system switches from fuel pump supply mode to fuel pump and compressor joint supply mode, the balance control module prioritizes the start of the BOG compressor with shorter running time, and the BOG compressor prioritizes the processing of fuel vapor gas in the fuel tank with higher pressure.

[0038] When the ship's fuel supply system switches from compressor supply mode to a combined fuel pump and compressor supply mode, the balance control module prioritizes the activation of the low-pressure fuel pump in the fuel tank with the higher liquid level and less running time.

[0039] When the ship's fuel supply system switches from a combined fuel pump and compressor supply mode to a fuel pump supply mode, the balance control module controls the initial frequency of the low-pressure fuel pump to a preset frequency parameter in the operating condition database.

[0040] Furthermore, the ship fuel supply system also includes a return pipeline, one end of which is connected to the outlet pipeline of the BOG compressor, and the other end of which is connected to the inlet pipeline of the BOG compressor. The return pipeline is used to partially return the fuel vapor gas processed by the BOG compressor to regulate the supply of fuel vapor gas. A return regulating valve is provided on the return pipeline, and the balance control module is electrically connected to the return regulating valve. The balance control module is also used to control the ship fuel supply system to perform the following actions:

[0041] Action 11: When the ship's fuel supply system switches from a combined fuel pump and compressor supply mode to a compressor supply mode, the balance control module controls the reflux regulating valve on the reflux pipeline to close, so as to mitigate the impact of the switching process on the supply pressure; then the balance control module adjusts the opening of the reflux regulating valve to ensure that the supply pressure meets the requirements.

[0042] Furthermore, both fuel tanks are equipped with pressure sensors and level sensors. The pressure sensors monitor the pressure in the fuel tanks, and the level sensors monitor the fuel level. Both pressure and level sensors are electrically connected to the balance control module, enabling the module to make judgments and take corresponding control actions based on the measured pressure and level values.

[0043] Furthermore, pressure transmitters (not shown in the figure) are installed on the outlet pipes of the BOG compressor, the low-pressure fuel pump, the high-pressure fuel pump, the first circulation pump, and the second circulation pump. Each pressure transmitter is electrically connected to the balance control module. When the pressure transmitter at the equipment outlet alarms with a high-high or low-low signal for a period of time, the moving equipment is considered to have failed.

[0044] Furthermore, each pipeline is equipped with a control valve, which is electrically connected to the balance control module.

[0045] The ship fuel supply system provided by this invention, by setting up a balance control module, can automatically regulate the low-pressure fuel pump, BOG compressor, liquid phase filling valve, and return gas valve, thereby automatically regulating the liquid level difference and pressure difference between the two fuel tanks during fuel filling and fuel supply to maintain stability, reducing or avoiding the original manual operation and regulation, reducing the burden on the crew, and improving the system's ability to cope with emergencies; at the same time, it can minimize the impact of adjusting the equipment on the system supply pressure and supply temperature, improving the system's stability. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the ship fuel supply system in an embodiment of the present invention.

[0047] Figure 2 This is a schematic diagram of the control logic of the balance control module in an embodiment of the present invention. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] 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.

[0051] like Figure 1 and Figure 2 As shown, the ship fuel supply system provided in this embodiment of the invention includes two fuel tanks 1, a fuel pump assembly, a BOG compressor 2, a fuel equipment 3, a balance control module 4, a fuel filling liquid inlet pipeline 51, and a fuel filling gas return pipeline 52. The fuel tanks 1 are used to store fuel (the fuel can be LNG, liquid ammonia, etc.). The two fuel tanks 1 are located on the port and starboard sides of the ship (specifically, the two fuel tanks 1 are symmetrically arranged on the port and starboard sides of the ship) to ensure the ship's load balance.

[0052] The fuel pump assembly includes low-pressure fuel pumps 61 respectively installed in two fuel tanks 1 (i.e., each of the two fuel tanks 1 is equipped with a low-pressure fuel pump 61). The low-pressure fuel pumps 61 in both fuel tanks 1 are connected to the fuel equipment 3. The low-pressure fuel pumps 61 can pump out the fuel in the fuel tanks 1 to supply the liquid fuel in the fuel tanks 1 to the fuel equipment 3 (the fuel equipment 3 is the equipment that consumes fuel, such as the ship's main engine, ship's generator, ship's boiler, etc.).

[0053] The BOG compressor 2 is connected to two fuel tanks 1 and a fuel equipment 3 respectively (specifically, the BOG compressor 2 is connected to the gas phase outlet of the fuel tank 1). The BOG compressor 2 is used to pressurize the fuel vapor gas (i.e., BOG, Boil-Off Gas, which is the gas generated after the liquid fuel evaporates) in the fuel tank 1 and supply it to the fuel equipment 3.

[0054] The fuel filling inlet pipeline 51 is connected to the fuel filling ports of the two fuel tanks 1 via liquid phase filling valves 53 (i.e., liquid phase filling valves 53 are respectively installed between the two fuel tanks 1 and the fuel filling inlet pipeline 51). The fuel filling return gas pipeline 52 is connected to the return gas ports of the two fuel tanks 1 via return gas valves 54 (i.e., return gas valves 54 are respectively installed between the two fuel tanks 1 and the fuel filling return gas pipeline 52). The fuel filling inlet pipeline 51 and the fuel filling return gas pipeline 52 are used for fuel filling of the fuel tanks 1. During fuel filling, both the fuel filling inlet pipeline 51 and the fuel filling return gas pipeline 52 are connected to the corresponding pipelines in the fuel filling station. Liquid fuel from the fuel filling station is injected into the two fuel tanks 1 through the fuel filling inlet pipeline 51; at the same time, the gas in the two fuel tanks 1 is discharged to the fuel filling station through the fuel filling return gas pipeline 52 to maintain the pressure stability in the fuel tanks 1.

[0055] The balance control module 4 is electrically connected to the low-pressure fuel pump 61, BOG compressor 2, liquid phase filling valve 53, and return gas valve 54, respectively. The balance control module 4 is used to control the ship's fuel supply system to perform the following actions:

[0056] Action 1: When the ship's fuel supply system is in refueling mode (i.e., refueling fuel tank 1), the balance control module 4 controls both fuel tank 1's liquid phase refueling valves 53 and return gas valves 54 to open. If the liquid level difference between the two fuel tanks 1 exceeds a preset value, the balance control module 4 controls the liquid phase refueling valve 53 and return gas valve 54 of the fuel tank 1 with the higher liquid level to close, so that the fuel refueling inlet pipeline 51 only refuels the fuel tank 1 with the lower liquid level; when the liquid level difference between the two fuel tanks 1 is less than the preset value, the balance control module 4 controls the closed liquid phase refueling valve 53 and return gas valve 54 to reopen (i.e., reopen the closed liquid phase refueling valve 53 and return gas valve 54); thus ensuring that during the refueling process, the liquid level difference between the two fuel tanks 1 is within the preset range, thereby ensuring the ship's load balance.

[0057] Action 2: When the ship's fuel supply system is in supply mode (i.e., when fuel tank 1 supplies fuel to fuel equipment 3), the balance control module 4 controls the low-pressure fuel pump 61 in one of the fuel tanks 1 to operate, that is, to supply fuel to fuel equipment 3 using one of the fuel tanks 1. If the liquid level difference between the two fuel tanks 1 exceeds a preset value, the balance control module 4 controls the low-pressure fuel pump 61 in the fuel tank 1 with the low liquid level to uniformly reduce its operating frequency until the low-pressure fuel pump 61 in the fuel tank 1 with the low liquid level stops operating; at the same time, it controls the low-pressure fuel pump 61 in the fuel tank 1 with the high liquid level to start. The initial operating frequency of the low-pressure fuel pump 61 in the fuel tank 1 with the high liquid level is the operating frequency of the low-pressure fuel pump 61 in the fuel tank 1 with the low liquid level before the switch (for example, the operating frequency of the low-pressure fuel pump 61 in the fuel tank 1 with the low liquid level before the switch is 90Hz; during the switch, the low-pressure fuel pump 61 in the fuel tank 1 with the low liquid level reduces its operating frequency uniformly until it stops operating, while the low-pressure fuel pump 61 in the fuel tank 1 with the high liquid level starts operating at an operating frequency of 90Hz), thereby ensuring that the system's supply pressure and supply flow remain stable during the switch.

[0058] Action 3: When the ship's fuel supply system is in refueling mode, the balance control module 4 controls both the liquid phase refueling valve 53 and the return gas valve 54 of the two fuel tanks 1 to open. If the pressure difference between the two fuel tanks 1 exceeds the set value, the balance control module 4 controls the return gas valve 54 of the high-pressure fuel tank 1 to open and the return gas valve 54 of the low-pressure fuel tank 1 to close, thereby reducing the pressure in the high-pressure fuel tank 1 and increasing the pressure in the low-pressure fuel tank 1 to reduce the pressure difference between them; when the pressure difference between the two fuel tanks 1 is less than the set value, the closed return gas valve 54 is reopened (i.e., the closed return gas valve 54 is reopened).

[0059] Action 4: When the ship's fuel supply system is in supply mode, and BOG compressor 2 is not involved in fuel supply; if the pressure difference between the two fuel tanks 1 exceeds the set value, and the fuel equipment 3 is under high-load supply conditions with a load greater than or equal to 50% (i.e., the load of fuel equipment 3 is greater than or equal to 50%), then the balance control module 4 controls BOG compressor 2 to start, in order to process the fuel vapor in the high-pressure fuel tank 1 (i.e., the control valve (not shown) between the high-pressure fuel tank 1 and BOG compressor 2 opens, so that the fuel vapor in the high-pressure fuel tank 1 is discharged to BOG compressor 2 for processing; while the control valve between the low-pressure fuel tank 1 and BOG compressor 2 is closed); when the pressure difference between the two fuel tanks 1 is less than the set value, BOG compressor 2 is then controlled to shut down. In supply mode, if BOG compressor 2 is involved in fuel supply, the balance control module 4 does not need to act, and BOG compressor 2 will automatically process the high-pressure fuel tank 1 to the set pressure.

[0060] If the pressure difference between the two fuel tanks 1 exceeds the set value, and the fuel equipment 3 is in a low-load supply condition with a load of less than 50% (i.e., the load of the fuel equipment 3 is less than 50%), the balance control module 4 controls the return gas valves 54 of both fuel tanks 1 to open, so that the two fuel tanks 1 are connected through the fuel filling return gas pipeline 52 to exchange gases, thereby reducing the pressure difference between the two fuel tanks 1; when the pressure difference between the two fuel tanks 1 is less than the set value, the return gas valves 54 of the two fuel tanks 1 are then controlled to close.

[0061] Under high-load supply conditions, the fuel supply from BOG compressor 2 accounts for a small proportion of the total fuel supply, thus having minimal impact on the pump supply process (i.e., fuel is mainly supplied by low-pressure fuel pump 61; after BOG compressor 2 is turned on, low-pressure fuel pump 61 only needs to slightly adjust its operating frequency to ensure stable fuel supply pressure and flow). Therefore, BOG compressor 2 is used to exhaust gas from the high-pressure fuel tank 1. Under low-load supply conditions, the fuel supply from BOG compressor 2 accounts for a relatively large proportion of the total fuel supply, thus having a significant impact on the pump supply process (at this time, after BOG compressor 2 is turned on, low-pressure fuel pump 61 needs to significantly adjust its operating frequency to ensure stable fuel supply pressure and flow). Therefore, pressure balancing through gas exchange between fuel tanks 1 is selected for this condition.

[0062] The ship fuel supply system provided in this embodiment of the invention, by setting up a balance control module 4, can automatically regulate the low-pressure fuel pump 61, BOG compressor 2, liquid phase filling valve 53 and return gas valve 54, thereby automatically regulating the liquid level difference and pressure difference between the two fuel tanks 1 during fuel filling and fuel supply to maintain stability, reducing or avoiding the original manual operation and regulation, reducing the burden on the crew, and improving the system's ability to cope with emergencies (i.e., the focus of this invention is on the control logic of the balance control module 4); at the same time, it can minimize the impact on the system supply pressure and supply temperature when adjusting the equipment, thereby improving the system's stability.

[0063] Furthermore, such as Figure 1As shown, in this embodiment, each fuel tank 1 is equipped with two low-pressure fuel pumps 61 connected in parallel (i.e., the two low-pressure fuel pumps 61 in each fuel tank 1 are connected in parallel and are both connected to the fuel equipment 3, with each low-pressure fuel pump 61 serving as a backup for the other). When the balance control module 4 controls the ship's fuel supply system to perform the above-mentioned action two, the balance control module 4 controls the low-pressure fuel pump 61 in the fuel tank 1 with a high liquid level to start, which has a shorter operating time, thereby reducing the difference in operating time between the low-pressure fuel pumps 61 and extending the service life of the equipment.

[0064] Furthermore, such as Figure 1 As shown, in this embodiment, the balance control module 4 is also used to control the ship's fuel supply system to perform the following actions:

[0065] Action 5: When the ship's fuel supply system is in supply mode, if the low-pressure fuel pump 61 in the currently used fuel tank 1 fails, the balance control module 4 will prioritize controlling the other low-pressure fuel pump 61 in the currently used fuel tank 1 to start (i.e., priority will be given to not switching the supply of fuel tank 1, that is, priority will be given to using the same fuel tank 1 for fuel supply); if the other low-pressure fuel pump 61 in the currently used fuel tank 1 fails to start normally, the balance control module 4 will control the low-pressure fuel pump 61 in the other fuel tank 1 with a shorter running time to start.

[0066] Furthermore, such as Figure 1 As shown, in this embodiment, there are two BOG compressors 2, connected in parallel, with each compressor serving as a backup for the other. The balance control module 4 is also used to control the ship's fuel supply system to perform the following actions:

[0067] Action 6: When one of the BOG compressors 2 fails during operation, the balance control module 4 controls the other BOG compressor 2 to start.

[0068] Furthermore, in this embodiment, when the balance control module 4 controls the ship's fuel supply system to perform the above-mentioned action four, the balance control module 4 prioritizes controlling the BOG compressor 2, which has a shorter running time, to start.

[0069] Furthermore, such as Figure 1 As shown in this embodiment, when the ship's fuel supply system is in a fuel pump and compressor co-supply mode, if the BOG compressor 2 fails, the balance control module 4 controls the other BOG compressor 2 to start, and at the same time controls the low-pressure fuel pump 61 to increase its operating frequency for a period of time; after the other BOG compressor 2 starts successfully, the balance control module 4 controls the low-pressure fuel pump 61 to restore its operating frequency, thereby reducing the impact of fuel supply pressure and supply flow during the switching process.

[0070] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, the fuel pump assembly also includes a high-pressure fuel pump 62 located between the low-pressure fuel pump 61 and the fuel equipment 3, situated within the two fuel tanks 1. The high-pressure fuel pump 62 is used to pressurize the fuel, and the balance control module 4 is electrically connected to the high-pressure fuel pump 62. There are two high-pressure fuel pumps 62, connected in parallel. The balance control module 4 is also used to control the ship's fuel supply system to perform the following actions:

[0071] Action 7: When one of the high-pressure fuel pumps 62 fails during operation, the balance control module 4 controls the other high-pressure fuel pump 62 to start.

[0072] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, the ship's fuel supply system also includes a first heat exchange system 7. A fuel heating device 63 is also provided between the low-pressure fuel pumps 61 in the two fuel tanks 1 and the fuel equipment 3. The fuel heating device 63 is used to heat the fuel. The first heat exchange system 7 is connected to the fuel heating device 63 and is used to heat the fuel heating device 63. The first heat exchange system 7 includes a heat source pipeline 71, a first circulation pump 72 for circulating the heat exchange medium, and a heater 73 for exchanging heat with the heat source. A heat source regulating valve 711 is provided on the heat source pipeline 71. The first circulation pump 72 is connected to both the fuel heating device 63 and the heater 73, and the heater 73 is connected to both the fuel heating device 63 and the heat source pipeline 71.

[0073] If the heat exchange medium is, for example, water / ethylene glycol, then the first circulation pump 72 is a water / ethylene glycol pump, and the heater 73 is a water / ethylene glycol heater. During operation, the heat exchange medium circulates between the first circulation pump 72, the heater 73, and the fuel heating device 63. The power for the circulation of the heat exchange medium comes from the first circulation pump 72. The heat exchange medium can exchange heat with the heat source (e.g., cylinder liner hot water) in the heat source pipeline 71 within the heater 73, thereby heating and raising the temperature of the heat exchange medium. After being heated, the heat exchange medium exchanges heat with the low-temperature fuel in the fuel heating device 63, thereby heating and raising the temperature of the low-temperature fuel to meet the supply temperature of the fuel device 3.

[0074] The balance control module 4 is electrically connected to the first circulation pump 72 and the heat source regulating valve 711. There are two first circulation pumps 72, connected in parallel. The balance control module 4 is also used to control the ship's fuel supply system to perform the following actions:

[0075] Action 8: When one of the first circulating pumps 72 fails during operation, the balance control module 4 controls the heat source regulating valve 711 on the heat source pipeline 71 to increase its opening, thereby temporarily increasing the heat source flow rate, and controls the other first circulating pump 72 to start; after the other first circulating pump 72 starts smoothly, the balance control module 4 adjusts the opening of the heat source regulating valve 711 (reducing the opening of the heat source regulating valve 711). Since the switching process of the first circulating pump 72 will cause fluctuations in the heat exchange medium circulation flow rate (the heat exchange medium circulation flow rate will temporarily decrease), by increasing the heat source flow rate, the temperature of the heat exchange medium will increase in a short time to offset the insufficient heat caused by the decrease in the heat exchange medium flow rate during the switching process, ensuring that the fuel supply temperature fluctuation meets the requirements of the fuel equipment 3.

[0076] Furthermore, such as Figure 1 As shown, in this embodiment, there are two heaters 73 and two heat source pipes 71. The two heaters 73 are connected in series and are respectively connected to two heat source pipes 71. When the balance control module 4 controls the ship's fuel supply system to perform the above-mentioned action eight, if one of the first circulation pumps 72 fails during operation, the balance control module 4 can also control the heat source regulating valve 711 on the backup heat source pipe 71 to open, that is, use the two heaters 73 to heat the heat exchange medium simultaneously, thereby increasing the temperature of the heat exchange medium in a short period of time and reducing temperature fluctuations.

[0077] Furthermore, such as Figure 1 As shown, in this embodiment, the fuel equipment 3 includes a high-pressure fuel equipment 32 and a low-pressure fuel equipment 31. The high-pressure fuel equipment 32 can be a ship's main engine, and the low-pressure fuel equipment 31 can be a ship's engine, ship's boiler, etc. The fuel heating equipment 63 includes a high-pressure vaporizer 632 and a low-pressure vaporizer 631. The high-pressure fuel pump 62 and the high-pressure vaporizer 632 are located between the low-pressure fuel pump 61 and the high-pressure fuel equipment 32, and the low-pressure vaporizer 631 is located between the low-pressure fuel pump 61 and the low-pressure fuel equipment 31. The BOG compressor 2 is connected to the low-pressure fuel equipment 31 and is used to supply fuel to the low-pressure fuel equipment 31. At this time, the fuel can be LNG, and the high-pressure vaporizer 632 can vaporize LNG into natural gas (when the fuel is liquid ammonia, since the ship's main engine requires a supply of liquid ammonia, the high-pressure vaporizer 632 can be replaced by a high-pressure heater). The first heat exchange system 7 is connected to the high-pressure vaporizer 632 and the low-pressure vaporizer 631 respectively, thereby heating the high-pressure vaporizer 632 and the low-pressure vaporizer 631.

[0078] Furthermore, such as Figure 1 and Figure 2As shown, in this embodiment, the ship fuel supply system also includes a second heat exchange system 8. A BOG preheater 21 is provided between the BOG compressor 2 and the two fuel tanks 1, and a BOG cooler 22 is provided between the BOG compressor 2 and the fuel equipment 3. The BOG preheater 21 is used to preheat the BOG (since the temperature of the BOG coming out of the fuel tank 1 is very low, it is necessary to preheat it using the BOG preheater 21 first). The BOG cooler 22 is used to cool the BOG after it has been compressed by the BOG compressor 2 (since the temperature of the BOG after it has been compressed by the BOG compressor 2 is very high, that is, the outlet temperature of the BOG compressor 2 is very high, the BOG cooler 22 is needed to cool it down).

[0079] The second heat exchange system 8 is connected to the BOG preheater 21 and the BOG cooler 22 respectively. The second heat exchange system 8 is used to heat the BOG preheater 21 and cool the BOG cooler 22. The second heat exchange system 8 includes a cold source pipeline 81, a second circulation pump 82 for circulating and transporting the heat exchange medium, and a heat exchange medium cooler 83 for exchanging heat with the cold source. The cold source pipeline 81 is equipped with a cold source regulating valve 811. The second circulation pump 82 is connected to the BOG preheater 21, the BOG cooler 22 and the heat exchange medium cooler 83 respectively. The heat exchange medium cooler 83 is connected to the cold source pipeline 81, the BOG preheater 21 and the BOG cooler 22 respectively.

[0080] If the heat exchange medium is, for example, water / ethylene glycol, then the second circulation pump 82 is a water / ethylene glycol pump, and the heat exchange medium cooler 83 is a water / ethylene glycol heater. During operation, the heat exchange medium circulates between the second circulation pump 82, the heat exchange medium cooler 83, and the BOG cooler 22, and also circulates between the second circulation pump 82, the heat exchange medium cooler 83, and the BOG preheater 21. The heat exchange medium can exchange heat with the cold source (e.g., low-temperature cooling water, approximately 36°C) in the cold source pipeline 81 within the heat exchange medium cooler 83, thereby cooling the heat exchange medium. After cooling, the heat exchange medium exchanges heat with the low-temperature BOG in the BOG preheater 21, thereby raising the temperature of the low-temperature BOG (because the temperature of the low-temperature BOG is very low, the temperature of the heat exchange medium must be higher than the temperature of the low-temperature BOG, thus enabling heat exchange and raising the temperature of the low-temperature BOG); the cooled heat exchange medium also exchanges heat with the high-temperature BOG in the BOG cooler 22, thereby cooling the high-temperature BOG.

[0081] The balance control module 4 is electrically connected to the second circulation pump 82 and the cold source regulating valve 811. There are two second circulation pumps 82, connected in parallel. The balance control module 4 is also used to control the ship's fuel supply system to perform the following actions:

[0082] Action 9: When one of the second circulation pumps 82 fails during operation, the balance control module 4 controls the cold source regulating valve 811 on the cold source pipeline 81 to increase its opening (e.g., adjust the opening of the cold source regulating valve 811 to be fully open), thereby temporarily increasing the flow rate of the cold source and controlling the other second circulation pump 82 to start; after the other second circulation pump 82 starts smoothly, the balance control module 4 then adjusts the opening of the cold source regulating valve 811 (reducing the opening of the cold source regulating valve 811). Since the second circulation pump 82 will cause fluctuations in the heat exchange medium circulation flow rate during the switching process (the heat exchange medium circulation flow rate will temporarily decrease), the cold source flow rate is increased to offset the insufficient cooling caused by the decrease in the heat exchange medium flow rate during the switching process, thereby ensuring that the BOG supply temperature fluctuation meets the requirements of the fuel equipment 3.

[0083] Furthermore, such as Figure 1 As shown, in this embodiment, the ship's fuel supply system has three modes: a fuel pump supply mode (i.e., the low-pressure fuel pump 61 pumps liquid fuel from the fuel tank 1 for supply), a compressor supply mode (i.e., the BOG compressor 2 compresses the BOG in the fuel tank 1 for supply), and a combined fuel pump and compressor supply mode (i.e., the low-pressure fuel pump 61 and the BOG compressor 2 supply fuel simultaneously). The system database presets operating parameters for different supply modes under different engine loads. The initial values ​​of these operating parameters are given by experience, and the operating parameters are updated as data from actual operating conditions are collected.

[0084] Balance control module 4 is also used to control the ship's fuel supply system to perform the following actions:

[0085] Action 10: When the ship's fuel supply system switches from fuel pump supply mode to fuel pump and compressor joint supply mode, the balance control module 4 prioritizes the start of BOG compressor 2, which has a shorter running time, and BOG compressor 2 prioritizes the processing of fuel vapor gas in fuel tank 1 with higher pressure.

[0086] When the ship's fuel supply system switches from compressor supply mode to fuel pump and compressor combined supply mode, the balance control module 4 prioritizes the activation of the low-pressure fuel pump 61 in the fuel tank 1 with higher liquid level and less running time.

[0087] When the ship's fuel supply system switches from a combined fuel pump and compressor supply mode to a fuel pump supply mode, the balance control module 4 controls the initial frequency of the low-pressure fuel pump 61 to a preset frequency parameter in the operating condition database.

[0088] Furthermore, such as Figure 1 and Figure 2As shown, in this embodiment, the ship fuel supply system further includes a return pipeline 23. One end of the return pipeline 23 is connected to the outlet pipeline of the BOG compressor 2, and the other end is connected to the inlet pipeline of the BOG compressor 2. The return pipeline 23 is used to partially return the fuel vapor gas processed by the BOG compressor 2 to regulate the supply of fuel vapor gas. A return regulating valve 231 is provided on the return pipeline 23, and the balance control module 4 is electrically connected to the return regulating valve 231. The balance control module 4 is also used to control the ship fuel supply system to perform the following actions:

[0089] Action 11: When the ship's fuel supply system switches from a fuel pump and compressor combined supply mode to a compressor supply mode, the balance control module 4 controls the return regulating valve 231 on the return pipeline 23 to close, so as to mitigate the impact of the switching process on the supply pressure; then the balance control module 4 adjusts the opening of the return regulating valve 231 (specifically, increases the opening of the return regulating valve 231) to ensure that the supply pressure meets the requirements (during the switching process, since the flow of the low-pressure fuel pump 61 decreases instantaneously, resetting the opening of the return regulating valve 231 to 0 can offset the impact of the switching process on the supply pressure).

[0090] Furthermore, such as Figure 1 and Figure 2 As shown, in this embodiment, each of the two fuel tanks 1 is equipped with a pressure sensor 11 and a level sensor 12. The pressure sensor 11 is used to monitor the pressure of the fuel tank 1, and the level sensor 12 is used to monitor the level of the fuel tank 1. Both the pressure sensor 11 and the level sensor 12 are electrically connected to the balance control module 4, so that the balance control module 4 can make judgments and take corresponding control actions based on the measured pressure and level values.

[0091] Furthermore, in this embodiment, pressure transmitters (not shown in the figure) are also installed on the outlet pipes of the BOG compressor 2, the low-pressure fuel pump 61, the high-pressure fuel pump 62, the first circulation pump 72, and the second circulation pump 82. Each pressure transmitter is electrically connected to the balance control module 4. When the pressure transmitter at the equipment outlet alarms with a high-high or low-low signal for a period of time, the moving equipment is considered to have failed.

[0092] Furthermore, in this embodiment, each pipeline is also equipped with a control valve (not shown in the figure), and the control valve is electrically connected to the balance control module 4.

[0093] Furthermore, such as Figure 1As shown in this embodiment, the balance control module 4 can be completed through a control system update based on the original system, without the need to add new instruments such as temperature, pressure, and liquid level gauges (i.e., the balance control module 4 can be added to the original control system through program updates, etc., and the balance control module 4 only needs to use the original control signals without adding hardware). The control parameters of the balance control module 4 can also be optimized online based on the actual operation results to continuously improve the system's operating performance.

[0094] Furthermore, such as Figure 1 and Figure 2 As shown, the main working process of the ship fuel supply system in this embodiment of the invention is as follows:

[0095] 1. The balance control module 4 can be used to monitor the liquid level changes in fuel tank 1 during fuel refueling and fuel supply. When the system detects that the liquid level difference between the two fuel tanks 1 is greater than a preset value, the balance control module 4 checks the current operating condition of the system.

[0096] In refueling mode, the balance control module 4 controls the liquid phase refueling valve 53 and the return gas valve 54 of the fuel tank 1 with high liquid level to close, so that the fuel refueling inlet pipeline 51 only refuels the fuel tank 1 with low liquid level; when the liquid level difference between the two fuel tanks 1 is less than the preset value, the balance control module 4 controls the closed liquid phase refueling valve 53 and the return gas valve 54 to reopen.

[0097] In supply mode, the rotational speed of the low-pressure fuel pump 61 in the low-level fuel tank 1 switches from supply pressure PID control to control by the balance control module 4. The balance control module 4 controls the low-pressure fuel pump 61 in the low-level fuel tank 1 to uniformly reduce its operating frequency until the low-pressure fuel pump 61 in the low-level fuel tank 1 stops operating. That is, the operating frequency of the low-pressure fuel pump 61 satisfies: f(t) = f0 - kt, where f(t) is the low-pressure fuel pump frequency, f0 is the initial frequency value, k is the set coefficient value, and t is time. At the same time, the balance control module 4 controls the low-pressure fuel pump 61 in the high-level fuel tank 1, which has a shorter operating time, to start. The initial operating frequency of the low-pressure fuel pump 61 in the high-level fuel tank 1 is the same as the operating frequency of the low-pressure fuel pump 61 in the low-level fuel tank 1 before the switch, and the rotational speed of this low-pressure fuel pump 61 is controlled by the supply pressure PID.

[0098] 2. The balance control module 4 can be used to monitor the pressure changes in fuel tank 1 during fuel filling and fuel supply. When the system detects that the pressure difference between the two fuel tanks 1 exceeds the set value, the balance control module 4 checks the current operating condition of the system.

[0099] In refueling mode, the balance control module 4 controls the return air valve 54 of the high-pressure fuel tank 1 to open and the return air valve 54 of the low-pressure fuel tank 1 to close, so that the pressure of the high-pressure fuel tank 1 decreases and the pressure of the low-pressure fuel tank 1 increases, thereby reducing the pressure difference between the two; when the pressure difference between the two fuel tanks 1 is less than the set value, the closed return air valve 54 is controlled to reopen.

[0100] In supply mode, if no BOG compressor 2 is involved in fuel supply, and the fuel supply equipment 3 is under high load (50% or higher), the balance control module 4 controls the BOG compressor 2, which operates for shorter periods, to start and process the fuel vapor in the high-pressure fuel tank 1. Once the pressure difference between the two fuel tanks 1 is less than the set value, the BOG compressor 2 is shut down. When the fuel supply equipment 3 is under low load (less than 50%), the balance control module 4 controls both fuel tanks 1's return gas valves 54 to open, connecting them via the fuel refueling return gas pipeline 52. Once the pressure difference between the two fuel tanks 1 is less than the set value, the return gas valves 54 of both fuel tanks 1 are closed. In supply mode, if BOG compressor 2 is involved in fuel supply, the balance control module 4 does not need to operate; BOG compressor 2 will automatically reduce the high-pressure fuel tank 1 to the set pressure.

[0101] 3. When the system detects an alarm from the control or safety system, indicating a failure of the system's moving equipment and the need for equipment switching, the balance control module 4 performs pre-adjustment. Moving equipment failures mainly include: low-pressure fuel pump failure, compressor failure, high-pressure fuel pump failure, and water / glycol pump failure. System moving equipment failure is primarily detected by monitoring the equipment's outlet pressure transmitter. When the outlet pressure transmitter alarms with a high-high or low-low signal and persists for a period of time, it is considered a moving equipment failure.

[0102] When low-pressure fuel pump 61 fails, the balance control module 4 prioritizes the activation of another low-pressure fuel pump 61 within the same fuel tank 1. The initial operating frequency of this low-pressure fuel pump 61 is a preset frequency parameter in the operating condition database. If this low-pressure fuel pump 61 fails to activate normally, the balance control module 4 activates another low-pressure fuel pump 61 within the same fuel tank 1 that has been running for a shorter period.

[0103] When BOG compressor 2 fails, the balance control module 4 prioritizes the start of the other BOG compressor 2. If the ship's fuel supply system is in a fuel pump and compressor co-supply mode at this time, the balance control module 4 also controls the low-pressure fuel pump 61 to increase its operating frequency for a period of time (the frequency of the low-pressure fuel pump 61 is prioritized by PID control of the supply pressure, so that its operating frequency increases in a short period of time); after the other BOG compressor 2 starts successfully, the balance control module 4 then controls the low-pressure fuel pump 61 to restore its operating frequency.

[0104] When the high-pressure fuel pump 62 fails, the balance control module 4 prioritizes the start of another high-pressure fuel pump 62, whose initial operating frequency is a preset frequency parameter in the operating condition database.

[0105] When the first circulating pump 72 fails, the balance control module 4 prioritizes starting the other first circulating pump 72. Since the switching process of the first circulating pump 72 causes fluctuations in the heat exchange medium circulation flow, the balance control module 4 preemptively controls the heat source regulating valve 711 on the heat source pipeline 71 to increase its opening, or controls the heat source regulating valve 711 on the standby heat source pipeline 71 to open, thereby temporarily increasing the heat source flow and ensuring that the fuel supply temperature fluctuations meet the requirements of the fuel equipment 3. After the other first circulating pump 72 starts successfully, the opening of the heat source regulating valve 711 is then adjusted.

[0106] When the second circulation pump 82 fails, the balance control module 4 prioritizes starting the other second circulation pump 82. Since the switching process of the second circulation pump 82 causes fluctuations in the heat exchange medium circulation flow, the balance control module 4 preemptively increases the opening of the cold source regulating valve 811 on the cold source pipeline 81 (e.g., adjusting the cold source regulating valve 811 to the fully open state) to ensure that the BOG supply temperature fluctuations meet the requirements of the fuel equipment 3. After the other second circulation pump 82 starts successfully, the opening of the cold source regulating valve 811 is then adjusted.

[0107] 4. When the system detects a change in the type of operating equipment, i.e., a change in the system supply mode, the system adjusts itself according to the current supply volume and the preset frequency parameters in the gas supply equipment matching database. Marine fuel supply systems generally have fuel pump supply mode, compressor supply mode, and a combined fuel pump and compressor supply mode. The system database presets operating parameters for different supply modes under different engine loads. These initial values ​​are given by experience, and the operating parameters are updated based on actual operating data.

[0108] When the ship's fuel supply system switches from fuel pump supply mode to fuel pump and compressor joint supply mode, the balance control module 4 prioritizes the start of BOG compressor 2, which has a shorter running time, and BOG compressor 2 prioritizes the processing of fuel vapor gas in fuel tank 1 with higher pressure.

[0109] When the ship's fuel supply system switches from compressor supply mode to a combined fuel pump and compressor supply mode, the balance control module 4 prioritizes the activation of the low-pressure fuel pump 61 and high-pressure fuel pump 62 in the fuel tank 1 with higher liquid levels and shorter operating time.

[0110] When the ship's fuel supply system switches from a combined fuel pump and compressor supply mode to a fuel pump supply mode, the balance control module 4 controls the initial frequency values ​​of the low-pressure fuel pump 61 and the high-pressure fuel pump 62 to be preset frequency parameters in the operating condition database.

[0111] When the ship's fuel supply system switches from a combined fuel pump and compressor supply mode to a compressor supply mode, the balance control module 4 controls the return regulating valve 231 on the return pipeline 23 to close (i.e., the opening is 0) to mitigate the impact of the switching process on the supply pressure; then the balance control module 4 adjusts the opening of the return regulating valve 231 to ensure that the supply pressure meets the requirements.

[0112] The ship fuel supply system provided in this embodiment of the invention, by setting up a balance control module 4, can automatically regulate the low-pressure fuel pump 61, BOG compressor 2, liquid phase filling valve 53, and return gas valve 54, thereby automatically regulating the liquid level difference and pressure difference between the two fuel tanks 1 during fuel filling and fuel supply to maintain stability, reducing or avoiding the original manual operation and regulation, alleviating the burden on the crew, and improving the system's ability to cope with emergencies; at the same time, it can minimize the impact of adjusting the equipment on the system supply pressure and supply temperature, improving the system's stability. The advantages of this ship fuel supply system include:

[0113] 1. Reduce the need for manual operation and improve the system's ability to respond to emergencies. Using the balance control module 4 for automated control can reduce the need for manual operation in situations such as fuel tank level differences and fuel tank pressure differences, thus reducing the burden on the crew.

[0114] 2. Improve the service life of pumps, compressors, and other equipment. The balance control module 4 intervenes in system emergencies, reducing the impact of equipment switching processes on system stability. The balance control module 4 can scientifically manage equipment operating time, reducing differences in operating time between moving and non-moving equipment to extend their service life.

[0115] 3. Ensure stable fuel supply temperature and pressure. The balance control module 4 can be used to control the system during operating condition switching, ensuring stable switching between different operating conditions and improving system stability.

[0116] 4. The balance control module 4 can be added to the existing system through a control system update without the need for new temperature, pressure, or level instruments (i.e., the balance control module 4 can be added to the original control system through program updates, etc., and only needs to use the existing control signals without adding hardware). The control parameters of the balance control module 4 can also be optimized online based on the actual operating results, continuously improving the system's operating performance.

[0117] This ship fuel supply system can be used not only for a single fuel supply system, but also for a dual fuel supply system or a system that supplies more than one type of fuel.

[0118] 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 fuel supply system, characterized in that, The system includes two fuel tanks (1), a fuel pump assembly, a BOG compressor (2), a fuel equipment (3), a balance control module (4), a fuel filling inlet line (51), and a fuel filling return line (52); the two fuel tanks (1) are located on the port and starboard sides of the vessel; the fuel pump assembly includes low-pressure fuel pumps (61) respectively located in the two fuel tanks (1), and the low-pressure fuel pumps (61) in the two fuel tanks (1) are connected to the fuel equipment (3) to supply liquid fuel in the fuel tanks (1) to the fuel equipment (3); the BOG compressor (2) is connected to the two fuel tanks (1) and the fuel equipment (3) respectively. 3) Connected to supply the fuel vapor gas in the fuel tank (1) to the fuel equipment (3); the fuel filling inlet pipeline (51) is connected to the fuel filling ports of the two fuel tanks (1) through the liquid phase filling valve (53), and the fuel filling return gas pipeline (52) is connected to the return gas ports of the two fuel tanks (1) through the return gas valve (54); the balance control module (4) is electrically connected to the low-pressure fuel pump (61), the BOG compressor (2), the liquid phase filling valve (53) and the return gas valve (54), and the balance control module (4) is used to control the ship fuel supply system to perform the following actions: Action 1: When the ship's fuel supply system is in refueling mode, if the liquid level difference between the two fuel tanks (1) exceeds a preset value, the balance control module (4) controls the liquid phase refueling valve (53) and return gas valve (54) of the fuel tank (1) with the high liquid level to close, so that the fuel refueling inlet pipeline (51) only refuels the fuel tank (1) with the low liquid level; when the liquid level difference between the two fuel tanks (1) is less than the preset value, the balance control module (4) controls the closed liquid phase refueling valve (53) and return gas valve (54) to reopen. Action 2: When the ship's fuel supply system is in supply mode, if the liquid level difference between the two fuel tanks (1) exceeds a preset value, the balance control module (4) controls the low-pressure fuel pump (61) in the fuel tank (1) with the low liquid level to uniformly reduce its operating frequency until the low-pressure fuel pump (61) in the fuel tank (1) with the low liquid level stops operating; at the same time, it controls the low-pressure fuel pump (61) in the fuel tank (1) with the high liquid level to start, and the initial operating frequency of the low-pressure fuel pump (61) in the fuel tank (1) with the high liquid level is the operating frequency of the low-pressure fuel pump (61) in the fuel tank (1) with the low liquid level before switching. Action 3: When the ship's fuel supply system is in refueling mode, if the pressure difference between the two fuel tanks (1) exceeds the set value, the balance control module (4) controls the return air valve (54) of the high-pressure fuel tank (1) to open and controls the return air valve (54) of the low-pressure fuel tank (1) to close; when the pressure difference between the two fuel tanks (1) is less than the set value, the closed return air valve (54) is controlled to reopen. Action 4: When the ship's fuel supply system is in supply mode, if the pressure difference between the two fuel tanks (1) exceeds the set value, and the fuel equipment (3) is in a high-load supply condition with a load greater than or equal to 50%, the balance control module (4) controls the BOG compressor (2) to start, so as to process the fuel vapor gas in the high-pressure fuel tank (1); when the pressure difference between the two fuel tanks (1) is less than the set value, the BOG compressor (2) is controlled to shut down. If the pressure difference between the two fuel tanks (1) exceeds the set value, and the fuel equipment (3) is in a low-load supply condition with a load of less than 50%, the balance control module (4) controls the return gas valves (54) of the two fuel tanks (1) to open, so that the two fuel tanks (1) are connected through the fuel filling return gas pipeline (52); when the pressure difference between the two fuel tanks (1) is less than the set value, the return gas valves (54) of the two fuel tanks (1) are then controlled to close.

2. The ship fuel supply system as described in claim 1, characterized in that, Each of the fuel tanks (1) is equipped with two low-pressure fuel pumps (61) connected in parallel; when the balance control module (4) controls the ship's fuel supply system to perform the above-mentioned action two, the balance control module (4) controls the low-pressure fuel pump (61) in the fuel tank (1) with a high liquid level to start, which has a shorter running time.

3. The ship fuel supply system as described in claim 1, characterized in that, Each of the fuel tanks (1) is equipped with two low-pressure fuel pumps (61) connected in parallel; the balance control module (4) is also used to control the ship's fuel supply system to perform the following actions: Action 5: When the ship's fuel supply system is in supply mode, if the low-pressure fuel pump (61) in the currently used fuel tank (1) fails, the balance control module (4) will prioritize controlling the other low-pressure fuel pump (61) in the currently used fuel tank (1) to start; if the other low-pressure fuel pump (61) in the currently used fuel tank (1) fails to start normally, the balance control module (4) will control the low-pressure fuel pump (61) in the other fuel tank (1) with a shorter running time to start.

4. The ship fuel supply system as described in claim 1, characterized in that, The number of BOG compressors (2) is two, and the two BOG compressors (2) are connected in parallel; the balance control module (4) is also used to control the ship's fuel supply system to perform the following actions: Action 6: When one of the BOG compressors (2) fails during operation, the balance control module (4) controls the other BOG compressor (2) to start.

5. The ship fuel supply system as described in claim 4, characterized in that, When the ship's fuel supply system is in the mode of fuel pump and compressor supply, if the BOG compressor (2) fails, the balance control module (4) controls the other BOG compressor (2) to start, and at the same time controls the low-pressure fuel pump (61) to increase its operating frequency for a period of time; after the other BOG compressor (2) starts successfully, the balance control module (4) controls the low-pressure fuel pump (61) to restore its operating frequency.

6. The ship fuel supply system as described in claim 1, characterized in that, A high-pressure fuel pump (62) is also provided between the low-pressure fuel pump (61) in the two fuel tanks (1) and the fuel equipment (3). The balance control module (4) is electrically connected to the high-pressure fuel pump (62). There are two high-pressure fuel pumps (62), which are connected in parallel. The balance control module (4) is also used to control the ship's fuel supply system to perform the following actions: Action 7: When one of the high-pressure fuel pumps (62) fails during operation, the balance control module (4) controls the other high-pressure fuel pump (62) to start.

7. The ship fuel supply system as described in claim 1, characterized in that, The ship fuel supply system also includes a first heat exchange system (7). A fuel heating device (63) is provided between the low-pressure fuel pumps (61) in the two fuel tanks (1) and the fuel equipment (3). The first heat exchange system (7) is connected to the fuel heating device (63) and is used to heat the fuel heating device (63). The first heat exchange system (7) includes a heat source pipeline (71), a first circulating pump (72) for circulating the heat exchange medium, and a heater (73) for exchanging heat with the heat source. The system is equipped with a heat source regulating valve (711). The first circulating pump (72) is connected to the fuel heating device (63) and the heater (73) respectively. The heater (73) is connected to the fuel heating device (63) and the heat source pipeline (71) respectively. The balance control module (4) is electrically connected to the first circulating pump (72) and the heat source regulating valve (711) respectively. There are two first circulating pumps (72), and the two first circulating pumps (72) are connected in parallel. The balance control module (4) is also used to control the ship's fuel supply system to perform the following actions: Action 8: When one of the first circulation pumps (72) fails during operation, the balance control module (4) controls the heat source regulating valve (711) on the heat source pipeline (71) to increase its opening and controls the other first circulation pump (72) to start.

8. The ship fuel supply system as described in claim 1, characterized in that, The ship fuel supply system also includes a second heat exchange system (8). A BOG preheater (21) is provided between the BOG compressor (2) and the two fuel tanks (1). A BOG cooler (22) is provided between the BOG compressor (2) and the fuel equipment (3). The second heat exchange system (8) is connected to the BOG preheater (21) and the BOG cooler (22) respectively. The second heat exchange system (8) is used to heat the BOG preheater (21) and cool the BOG cooler (22). The second heat exchange system (8) includes a cold source pipeline (81), a second circulation pump (82) for circulating the heat exchange medium, and a heat exchange medium cooler for exchanging heat with the cold source. (83) A cold source regulating valve (811) is provided on the cold source pipeline (81). The second circulating pump (82) is connected to the BOG preheater (21), the BOG cooler (22) and the heat exchange medium cooler (83) respectively. The heat exchange medium cooler (83) is connected to the cold source pipeline (81), the BOG preheater (21) and the BOG cooler (22) respectively. The balance control module (4) is electrically connected to the second circulating pump (82) and the cold source regulating valve (811) respectively. There are two second circulating pumps (82), and the two second circulating pumps (82) are connected in parallel. The balance control module (4) is also used to control the ship fuel supply system to perform the following actions: Action 9: When one of the second circulation pumps (82) fails during operation, the balance control module (4) controls the cold source regulating valve (811) on the cold source pipeline (81) to increase its opening and controls the other second circulation pump (82) to start.

9. The ship fuel supply system as described in claim 1, characterized in that, The number of BOG compressors (2) is two, and the two BOG compressors (2) are connected in parallel; the balance control module (4) is also used to control the ship's fuel supply system to perform the following actions: Action 10: When the ship's fuel supply system switches from the fuel pump supply mode to the fuel pump and compressor joint supply mode, the balance control module (4) prioritizes the start of the BOG compressor (2) with less running time, and the BOG compressor (2) prioritizes the processing of fuel vapor gas in the fuel tank (1) with higher pressure. When the ship's fuel supply system switches from compressor supply mode to fuel pump and compressor combined supply mode, the balance control module (4) prioritizes the activation of the low-pressure fuel pump (61) in the fuel tank (1) with higher liquid level and less running time.

10. The ship fuel supply system as described in any one of claims 1-9, characterized in that, The ship fuel supply system also includes a return pipeline (23), one end of which is connected to the outlet pipeline of the BOG compressor (2), and the other end of which is connected to the inlet pipeline of the BOG compressor (2). The return pipeline (23) is used to partially return the fuel vapor gas processed by the BOG compressor (2) to regulate the supply of fuel vapor gas. A return regulating valve (231) is provided on the return pipeline (23), and the balance control module (4) is electrically connected to the return regulating valve (231). The balance control module (4) is also used to control the ship fuel supply system to perform the following actions: Action 11: When the ship's fuel supply system switches from the fuel pump and compressor combined supply mode to the compressor supply mode, the balance control module (4) controls the return regulating valve (231) on the return pipeline (23) to close.

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