KR102626177B1 - Fuel Supply System and Method For Ship - Google Patents

Abstract

A ship fuel supply system and method are disclosed. The ship's fuel supply system of the present invention includes a fuel supply line through which liquefied gas is supplied from a fuel supply tank provided on the ship to the ship's engine; A fuel supply pump provided in the fuel supply tank to pump liquefied gas into the fuel supply line; A pressurizing pump provided in the fuel supply line and pressurizing liquefied gas to the pressure required for the engine; A return line for recovering liquefied gas not consumed by the engine among the liquefied gas supplied to the engine to the upstream of the engine; A cooler provided in the fuel supply line and cooling the liquefied gas to be transferred to the pressurization pump; And a refrigerant supply line that supplies all or part of the liquefied gas pumped from the fuel supply pump as a refrigerant to the cooler, wherein the liquefied gas recovered through the return line is recirculated to the fuel supply line in front of the cooler. It is characterized by being

Description

Fuel supply system and method for ship {Fuel Supply System and Method For Ship}

The present invention relates to a fuel supply system and method for ships, and more specifically, to effectively supply fuel to the engine by recovering and recirculating the remaining liquefied gas that has been oversupplied to the engine in ships using liquefied gas such as LPG as fuel. It relates to a fuel supply system and method that can be used.

Consumption of liquefied gases such as LNG (Liquefied Natural Gas) and LPG (Liquefied Petroleum Gas) is rapidly increasing worldwide. Liquefied gas is transported in a gaseous state through gas pipes on land or at sea, or is stored in a liquefied state on a liquefied gas carrier and transported to a distant consumer. Liquefied gases such as LNG or LPG are obtained by cooling natural gas or petroleum gas to extremely low temperatures (approximately -163°C in the case of LNG), and their volume is significantly reduced compared to the gaseous state, making them very suitable for long-distance transportation by sea.

The liquefaction temperature of petroleum gas is low at about -42°C at normal pressure, and it can be stored in liquid form up to a temperature of about 45°C at 18 bar and up to 20°C at 7 bar. Since LPG evaporates when the atmospheric pressure is higher than -42℃, the ship's LPG storage tank is insulated. However, because external heat is continuously transferred to LPG, LPG is continuously vaporized within the LPG storage tank during the LPG transport process, generating boil-off gas within the LPG storage tank.

In LPG carriers, when boil-off gas accumulates in the LPG storage tank, the pressure inside the LPG storage tank rises excessively, so the LPG storage tank is equipped with a pressure-resistant structure and a boil-off gas reliquefaction device is used to process the boil-off gas generated within the tank. do.

Meanwhile, conventional LPG carriers, etc., adopt a fuel supply system that uses relatively inexpensive heavy oil such as bunker C oil as propulsion fuel for ships. This heavy oil fuel supply system has the international exhaust gas emissions associated with the use of heavy oil fuel. Due to strengthened regulations, a separate low-sulfur heavy fuel fuel tank (LSHFO tank) had to be installed, and the demand for an eco-friendly fuel supply system that meets international environmental regulation standards has increased.

Recently, the application of fuel supply systems that use LPG or LNG and boil-off gas generated therefrom as propulsion fuel has been increasing in LPG or LNG carriers, and in accordance with the strengthening of international exhaust gas emission regulations, in addition to LPG or LNG carriers, general ships also use LNG. The number of ships using propulsion fuel is increasing.

In particular, LPG is easier to store than LNG, which is liquefied at extremely low temperatures, and does not fall significantly in SPECIFIC ENERGY and ENERGY DENSITY compared to existing HFO, and has excellent savings in SOX, NOX, CO2, and PM compared to existing HFO.

On ships that use LPG as fuel, LPG to be supplied as fuel to the engine goes from the fuel supply tank through the fuel supply system, which includes a compression pump and heater, and is supplied to the ship's engine according to the fuel supply conditions of the engine. supplied.

Liquid LPG, which is an incompressible fluid, can be supplied in excess of the fuel required by the engine so that it can immediately respond to changes in engine load. The excess supply and consumption of LPG as fuel or the remaining LPG due to changes in fuel consumption rate due to changes in engine load LPG, LPG remaining in the engine and piping when the engine is stopped, is recovered upstream of the engine.

However, if the recovered LPG is discharged and burned as is, there is a problem of wasting fuel, and if it is sent to a cargo tank, there is a risk of contamination of the LPG cargo due to sealing oil flowing in from the engine. In addition, since the recovered LPG is compressed and heated according to the fuel supply conditions of the engine and is in a high temperature and high pressure state, there is a problem of increasing the pressure and temperature within the tank when it is sent to the fuel supply tank.

The present invention solves these problems and seeks to provide a system that can effectively process LPG recovered from an engine and effectively supply fuel.

According to one aspect of the present invention for solving the above-described problem, a fuel supply line for supplying liquefied gas from a fuel supply tank provided on the ship to the engine on board the ship;

A fuel supply pump provided in the fuel supply tank to pump liquefied gas into the fuel supply line;

A pressurizing pump provided in the fuel supply line and pressurizing liquefied gas to the pressure required for the engine;

A return line for recovering liquefied gas not consumed by the engine among the liquefied gas supplied to the engine to the upstream of the engine;

A cooler provided in the fuel supply line and cooling the liquefied gas to be transferred to the pressurization pump; and

A refrigerant supply line that supplies all or part of the liquefied gas pumped from the fuel supply pump to the cooler as a refrigerant,

A fuel supply system for a ship is provided, wherein the liquefied gas recovered through the return line is recirculated to the fuel supply line in front of the cooler.

Preferably, it further includes a first valve provided in the refrigerant supply line to control the flow rate of the liquefied gas supplied as a refrigerant to the cooler, wherein the refrigerant supply line is located upstream of the confluence of the return line and the fuel supply line. branched from and connected to the fuel supply tank through the cooler, and when the load of the engine is low and the amount of liquefied gas recirculated through the return line is large, the fuel supply line into which the recirculated liquefied gas is joined By cooling the liquefied gas in the cooler, the temperature of the liquefied gas supplied to the engine can be maintained below a certain temperature.

Preferably, a first temperature transmitter provided at a rear end of the cooler in the fuel supply line; a second temperature transmitter provided at the front of the cooler in the fuel supply line; And it may further include a flow meter provided at the front of the confluence point of the return line in the fuel supply line to detect the flow rate of the liquefied gas transferred from the fuel supply tank.

Preferably, it may further include a fuel heater provided in the fuel supply line and heating the liquefied gas pressurized by the pressurization pump to a temperature required by the engine.

Preferably, the fuel supply tank may be an atmospheric pressure tank disposed inside the hull of the ship.

Preferably, the return line includes: a first return line connected from the engine to a fuel supply line in front of the cooler; a second return line branched from the first return line and connected to a fuel supply line in front of the cooler via a catch tank connected to the vent mast of the ship; and a return line for heating connected from the fuel supply line at the rear end of the fuel heater to the fuel supply line at the front end of the cooler.

Preferably, the fuel supply line further includes a first pressure transmitter that detects the pressure at the rear end of the pressurization pump, and when the pressure detected by the first pressure transmitter is higher than the set value, the pump speed of the pressurization pump is first increased. lowered, and if it is still higher than the set value, some of the liquefied gas at the rear end of the pressurization pump can be discharged to the first return line to lower the pressure at the rear end of the pressurization pump.

Preferably, it further includes: a re-liquefaction unit for receiving and re-liquefying the boil-off gas generated from the cargo tank provided on the ship and storing the liquefied gas to be transported and the boil-off gas generated from the fuel supply tank, and in the re-liquefaction unit The fuel supply tank can be cooled by spraying the re-liquefied liquefied gas into the fuel supply tank.

According to another aspect of the present invention, liquefied gas is transferred from a fuel supply tank provided on a ship along a fuel supply line, and is pressurized by a pressurization pump to the pressure necessary for the engine onboard the ship and supplied as fuel,

Among the liquefied gas pressurized by the pressurization pump, the liquefied gas that is not consumed in the engine is recirculated along the return line to the fuel supply line upstream of the engine,

A cooler is provided downstream of the confluence point of the return line in the fuel supply line, and all or part of the liquefied gas transferred from the fuel supply tank is supplied to the cooler as a refrigerant, so that the recirculated liquefied gas is joined to the fuel supply line. A fuel supply method for ships is provided, which is characterized in that it can cool liquefied gas.

Preferably, the refrigerant supply line that supplies the liquefied gas transferred from the fuel supply tank as a refrigerant to the cooler branches off from the fuel supply line upstream of the confluence point of the return line and connects to the fuel supply tank via the cooler. When the load of the engine is low and the amount of liquefied gas recirculated through the return line is large, the liquefied gas of the fuel supply line to which the recirculated liquefied gas is joined is cooled in the cooler and supplied to the engine. The temperature of the liquefied gas can be maintained below a certain temperature.

In the present invention, liquefied gas not consumed in the engine can be recirculated along the return line to the front of the pressurizing pump upstream of the engine.

In particular, a cooler is provided in front of the pressurizing pump in the fuel supply line where the recirculated liquefied gas from the return line joins, and the low-temperature liquefied gas transferred from the fuel supply tank is supplied and cooled with the cooler's refrigerant, thereby supplying fuel without requiring a separate refrigerant. The liquefied gas temperature in the line can be effectively controlled.

Even if the engine load is low and the amount of recirculated liquefied gas recovered from the engine is large, the required temperature range in the engine can be maintained by cooling the liquefied gas through a cooler, and by recirculating the recirculated liquefied gas recovered from the engine to the fuel supply line. , it is possible to prevent the lubricant mixed in the fuel while passing through the engine from flowing into the fuel supply tank and prevent the temperature of the fuel supply tank from rising.

Figure 1 schematically shows a fuel supply system for a ship according to an embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objectives achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the structure and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Here, in adding reference numerals to components in each drawing, it should be noted that identical components are indicated with the same reference numerals as much as possible, even if they are shown in different drawings.

In the embodiment of the present invention described later, the ship may be any type of ship installed with an engine that can use liquefied petroleum gas as fuel for a propulsion engine or fuel for a power generation engine. Representative examples include ships with self-propelled capabilities such as LPG carriers, LNG carriers, liquid hydrogen carriers, and LNG RVs (Regasification Vessels), as well as LNG FPSOs (Floating Production Storage Offloading) and LNG FSRUs (Floating Storage Regasification Units). Marine structures that do not have propulsion capabilities but are floating in the sea may also be included.

In addition, this embodiment can be applied to a fuel supply system for all types of liquefied gas that can be liquefied at low temperature and transported, generate boil-off gas in a stored state, and be supplied as fuel for an engine. These liquefied gases are, for example, liquefied petrochemicals such as LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), Liquefied Ethylene Gas, and Liquefied Propylene Gas. It may be gas, ammonia, etc. However, in the examples described later, the application of LPG, one of the representative liquefied gases, will be described as an example.

Figure 1 schematically shows a fuel supply system for a liquefied gas carrier according to an embodiment of the present invention.

As shown in Figure 1, the fuel supply system of this embodiment is provided in the fuel supply line (SL), which supplies liquefied gas from the fuel supply tank (FT) provided on the ship to the engine (E) on board the ship, and the fuel supply tank. A fuel supply pump (FP) that transfers liquefied gas from the fuel supply tank to the engine, a pressurization pump (100) provided in the fuel supply line and pressurized liquefied gas to the pressure required for the engine, and liquefied gas that is not consumed by the engine among the liquefied gas. Return lines (RL1, RL2) that recirculate upstream of the engine, a return line (RL3) for heating to prevent system oil from freezing, and a cooler ( 300), includes a refrigerant supply line (CL) that branches off from the fuel supply line upstream of the confluence point of the return line and supplies all or part of the liquefied gas pumped from the fuel supply pump as a refrigerant to the cooler. The refrigerant supply line (CL) is connected to the fuel supply tank (FT) through the cooler 300, and the liquefied gas used as a refrigerant in the cooler is recovered to the fuel supply tank.

In the system of this embodiment, the liquefied gas that is not consumed and recovered from the engine is supplied and recirculated along the return lines (RL1, RL2) upstream of the engine and in front of the pressurized pump (100) of the fuel supply line (SL), especially fuel supply. A cooler (300) is provided downstream of the line's return line confluence, and the low-temperature liquefied gas pumped by the fuel supply pump (FP) and transferred from the fuel supply tank (FT) is supplied to the cooler along the refrigerant supply line (CL). By using it as a refrigerant, it is characterized by being able to effectively control the temperature of the liquefied gas in the fuel supply line without requiring a separate refrigerant.

If the ship of this embodiment is a ship that transports liquefied gas as cargo, such as an LPG carrier, a cargo tank (not shown) is provided to store and transport the cargo, LPG, and, separately from the cargo tank, liquefied gas to be used as fuel on the ship. A fuel supply tank to store fuel is provided separately on board the ship.

This fuel supply tank (FT) can be provided as a normal pressure refrigerated tank placed inside the ship's hull, and LPG is stored in the fuel supply tank at around 0 barg and -52 ℃ and compressed through the fuel supply line. And it can be heated and supplied to the engine at around 50 barg and 25 to 45°C. In this way, the fuel supply tank is prepared as an atmospheric pressure refrigerated tank in the hull, and a separate room temperature storage tank such as a C-Type tank is not placed on the upper deck, which reduces costs and makes it easier to secure installation space, and increases the weight of the upper deck. can be prevented. Additionally, since the hull experiences less temperature change than the upper part of the deck exposed to the external environment, evaporation gas generation from the fuel supply tank can be reduced.

The liquefied gas stored in the fuel supply tank (FT) is transferred to the fuel supply line (SL) through the fuel supply pump (FP) provided in the tank, is pressurized to the fuel supply pressure of the engine through the pressurization pump 100, and then is transferred to the fuel heater. At (200), it is heated to the temperature required by the engine and supplied to the engine. The fuel heater 200 may use, for example, glycol water, steam, or hot water as a heat source.

The fuel supply line (SL) may be additionally provided with a filter (not shown) and a service valve unit (not shown) that filter out foreign substances in the compressed liquefied gas fuel. The service valve unit supplies LPG to the engine, and when the LPG fuel supply is interrupted due to the engine's fuel oil change, LPG mode stop, trip, etc., each pipe is double blocked through the valve to relieve pressure in the pipe.

An example of an engine supplied with compressed and heated LPG as fuel may be the ME-LGIP engine from MAN Diesel & Turbo. In this case, LPG is transferred from the fuel supply pump and supplied to the engine as a high-pressure liquid at around 50 barg and 25 to 45 ℃ through a pressurized pump. It works.

In the engine of this embodiment, compressed and heated fuel is supplied to the engine in a liquid state. Unlike engines supplied with compressible fluid, i.e. gas fuel, whose volume changes greatly depending on pressure changes, there is no change in volume even when pressure is applied. When a small amount of incompressible fluid, liquid LPG, is supplied as engine fuel, sufficient fuel is supplied to immediately respond to changes in engine load, and excess LPG is supplied to the engine to prevent cavitation. Among the LPG supplied to the engine, the LPG remaining after being consumed as fuel can be discharged from the engine through a return line and recirculated. At this time, the LPG that is compressed and heated for fuel supply and then recovered through the return line from the engine is around 60℃, which is significantly higher than the LPG in the fuel supply tank. As the amount of recovered recirculated LPG increases, the temperature of LPG in the fuel supply system increases. rises. In particular, when the engine load is low and the amount of recirculated LPG recovered through the return line increases, the temperature of the LPG in the fuel supply system increases and may exceed the engine's fuel supply temperature range, and vapor is discharged from the suction of the pressurized pump. There is also a risk of (vapor) occurring.

In this embodiment, in order to solve this problem, a cooler 300 is provided downstream of the return line confluence point of the fuel supply line, and the recirculated liquefied gas is allowed to cool the joined liquefied gas. The low-temperature liquefied gas supplied from the fuel supply tank (FT) is branched to the refrigerant supply line (CL) and supplied to the cooler to be used as a refrigerant. For this purpose, the refrigerant supply line (CL) branches off from the fuel supply line (SL) upstream of the confluence of the return lines (RL1, RL2) and connects to the fuel supply tank (FT) through the cooler 300. A first valve (V1) is provided to control the flow rate of liquefied gas supplied as a refrigerant to the cooler. The first valve is provided at the rear end of the cooler in the refrigerant supply line to maintain back pressure.

A first temperature transmitter (TT1) is provided at the rear end of the cooler in the fuel supply line, and a second temperature transmitter (TT2) is provided at the front end of the cooler in the fuel supply line. A flow meter (FM) is provided at the front of the confluence of the return line in the fuel supply line to detect the flow rate of liquefied gas transferred from the fuel supply tank.

When the engine load is low and the amount of liquefied gas recirculated through the return line increases, the first and second temperature transmitters (TT1, TT2) detect the liquefied gas temperature before and after the cooler and open the first valve ( The flow rate of the liquefied gas supplied as a refrigerant to the cooler is adjusted through V1), and the liquefied gas in the fuel supply line with the recirculated liquefied gas is cooled and transferred to the pressurization pump (100).

Through this, the temperature of the liquefied gas supplied to the engine can be maintained at a constant temperature within the fuel supply temperature range.

In this embodiment, the return line passes through a first return line (RL1) connected from the engine to the fuel supply line at the front of the cooler, and a catch tank (CT) branched from the first return line and connected to the vent mast of the ship. It includes a second return line (RL2) connected to the fuel supply line, and a heating return line (RL3) connected from the fuel supply line behind the fuel heater to the fuel supply line in front of the cooler.

The heating return line (RL3) is provided with a second valve (V2) that opens and closes the pipe, and when the liquefied gas temperature at the rear of the cooler (300) detected by the first temperature transmitter (TT1) is -10°C or lower, The opening degree of the second valve (V2) is adjusted to prevent freezing of the system oil contained in the returned fuel, and when the temperature of the returned fuel is higher than 40°C, the opening degree of the first valve (V1) is adjusted to adjust the temperature. It has the function of dropping.

The liquefied gas discharged from the engine may be recirculated to the fuel supply line in front of the cooler through the first return line, and may be transferred to the catch tank (CT) through the second return line and then transferred to the fuel supply line in front of the cooler from the catch tank (CT). It may also be supplied through a supply line.

A filter (not shown) may be provided in the return line to filter out lubricating oil mixed in the liquefied gas discharged from the engine.

The fuel supply line is equipped with a first pressure transmitter (PT1) that detects the pressure at the rear end of the pressurization pump. When the pressure detected by the first pressure transmitter is higher than the set value, the pump speed of the pressurization pump is first lowered, and the pump speed is still lower than the set value. If it is high, some of the liquefied gas at the rear of the pressurization pump can be discharged to the first return line to lower the pressure at the rear of the pressurization pump.

The catch tank (CT) is equipped with a second pressure transmitter (PT2) that detects the tank pressure, and when the detected pressure becomes higher than a certain pressure, the pressure can be adjusted by discharging part of the gas to the vent mast (VM).

In this way, in the system of this embodiment, even though the engine load is low and the amount of liquefied gas recovered and recirculated through the return lines (RL1, RL2) is large, the low-temperature liquefied gas stored in the fuel supply tank (FT) is used as a refrigerant to cool the cooler ( By cooling the liquefied gas in the fuel supply line in 300), the temperature of the liquefied gas to be supplied as engine fuel can be appropriately adjusted without requiring a separate refrigerant. In addition, by recirculating the recirculated liquefied gas recovered from the engine to the fuel supply line, it is possible to prevent lubricating oil mixed into the fuel while passing through the engine from flowing into the fuel supply tank (FT).

The system of this embodiment is provided with a re-liquefaction unit (RS) capable of re-liquefying boil-off gas generated from liquefied gas such as a fuel supply tank and a cargo tank (not shown).

A liquid header (LH) capable of loading liquefied gas is connected to the fuel supply tank, and injection units (S1, S2, S3) are provided inside the fuel supply tank to spray the supplied liquefied gas into the tank. . A plurality of injection units may be provided along the height direction of the tank, and the liquefied gas re-liquefied through the re-liquefaction unit (RS) may be transferred to the liquid header and injected into the fuel supply tank through the injection unit.

The liquefied gas branched into the refrigerant supply line (CL) and used as a refrigerant for the cooler may be injected into the lower part of the tank through the injection unit (S3) provided at the lower part of the fuel supply tank.

It is clear to those skilled in the art that the present invention is not limited to the above-mentioned embodiments, and that it can be implemented with various modifications or variations without departing from the technical gist of the present invention. It is self-evident.

E: engine
FT: Fuel supply tank
SL: Fuel supply line
RL1, RL2: return line
RL3: Return line for heating
CL: Refrigerant supply line
100: Pressurization pump
200: Fuel heater
300: Cooler

Claims (10)

A fuel supply line that supplies liquefied gas from a fuel supply tank provided on the ship to the ship's engine;
A fuel supply pump provided in the fuel supply tank to pump liquefied gas into the fuel supply line;
A pressurizing pump provided in the fuel supply line and pressurizing liquefied gas to the pressure required for the engine;
A return line for recovering liquefied gas not consumed by the engine among the liquefied gas supplied to the engine to the upstream of the engine;
A cooler provided in the fuel supply line and cooling the liquefied gas to be transferred to the pressurization pump;
A refrigerant supply line that supplies all or part of the liquefied gas pumped from the fuel supply pump as a refrigerant to the cooler; and
A first valve provided at the rear end of the cooler of the refrigerant supply line to control the flow rate of liquefied gas supplied as refrigerant to the cooler,
The refrigerant supply line branches off from the fuel supply line upstream of the confluence point of the return line and connects to the fuel supply tank through the cooler,
A ship's fuel supply system, characterized in that the liquefied gas recovered through the return line is recirculated to the fuel supply line in front of the cooler. According to clause 1,
When the load of the engine is low and the amount of liquefied gas recirculated through the return line is large, the liquefied gas of the fuel supply line to which the recirculated liquefied gas is joined is cooled in the cooler and the liquefied gas is supplied to the engine. A ship's fuel supply system characterized by maintaining the temperature below a certain temperature. According to clause 2,
A first temperature transmitter provided at a rear end of the cooler in the fuel supply line;
a second temperature transmitter provided at the front of the cooler in the fuel supply line; and
A fuel supply system for a ship further comprising: a flow meter provided at the front of the confluence point of the return line in the fuel supply line to detect the flow rate of liquefied gas transferred from the fuel supply tank. According to clause 3,
A fuel supply system for a ship further comprising: a fuel heater provided in the fuel supply line and heating the liquefied gas pressurized by the pressurization pump to a temperature required by the engine. According to clause 4,
The fuel supply tank is a ship's fuel supply system, characterized in that the fuel supply tank is an atmospheric pressure tank disposed inside the hull of the ship. The method of claim 4, wherein the return line is:
a first return line connected from the engine to a fuel supply line in front of the cooler;
a second return line branched from the first return line and connected to a fuel supply line in front of the cooler via a catch tank connected to the vent mast of the ship; and
A fuel supply system for a ship including a heating return line connected from the fuel supply line at the rear end of the fuel heater to the fuel supply line at the front end of the cooler. According to clause 6,
It further includes a first pressure transmitter that senses the pressure at the rear end of the pressurization pump in the fuel supply line,
If the pressure detected by the first pressure transmitter is higher than the set value, the pump speed of the pressurization pump is first lowered, and if it is still higher than the set value, some of the liquefied gas at the rear end of the pressurization pump is discharged to the first return line and the pressure at the rear end of the pressurization pump is discharged. A ship's fuel supply system characterized by lowering pressure. According to any one of claims 1 to 7,
It further includes a re-liquefaction unit that receives and re-liquefies the boil-off gas generated from the cargo tank provided on the ship and storing the liquefied gas to be transported and the boil-off gas generated from the fuel supply tank,
A ship's fuel supply system, characterized in that the fuel supply tank can be cooled by spraying the liquefied gas reliquefied in the reliquefaction unit into the fuel supply tank. Liquefied gas is transported along the fuel supply line from the fuel supply tank provided on the ship, and is pressurized by a pressurization pump to the pressure required for the ship's engine and supplied as fuel.
Among the liquefied gas pressurized by the pressurization pump, the liquefied gas that is not consumed in the engine is recirculated along the return line to the fuel supply line upstream of the engine,
A cooler is provided downstream of the confluence point of the fuel supply line and the return line,
A refrigerant supply line that supplies the liquefied gas transferred from the fuel supply tank as a refrigerant to the cooler branches off from the fuel supply line upstream of the confluence of the return line and connects to the fuel supply tank through the cooler,
A fuel supply method for a ship, characterized in that all or part of the liquefied gas transferred from the fuel supply tank is supplied as a refrigerant to the cooler to cool the liquefied gas in the fuel supply line to which the recirculated liquefied gas is joined. According to clause 9,
When the load of the engine is low and the amount of liquefied gas recirculated through the return line is large, the liquefied gas of the fuel supply line to which the recirculated liquefied gas is joined is cooled in the cooler and the liquefied gas is supplied to the engine. A fuel supply method for ships, characterized in that the temperature of is maintained below a certain temperature.

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