JP2021527590A - Fuel supply system and fuel supply method for ships - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose a fuel supply system for a ship.
A fuel supply system for a ship is compressed by a pump (10) that pressurizes liquefied gas discharged from a storage tank (T) to a required pressure of an engine (E) and the pump (10). It passes through the heat exchanger (20) that heats the liquefied gas to the required temperature of the engine (E) by heat exchange, and the pump (10) and the heat exchanger (20) that are discharged from the storage tank (T). It is provided with a buffer tank (50) that temporarily stores the liquefied gas and supplies it to the engine (E). By supplying gas to the buffer tank (50) via the gas supply line (F3), the internal pressure of the buffer tank (50) is adjusted, and the amount of liquefied gas required by the engine (E) is adjusted. Is supplied from the buffer tank (50) to the engine (E).
[Selection diagram] Fig. 2

Description

The present invention relates to a fuel supply system and a fuel supply method in a ship that uses an incompressible fluid as a fuel for an engine.

Generally, petroleum gas is produced in the state of liquefied petroleum gas (Liquefied Petroleum Gas, hereinafter referred to as LPG) liquefied at a low temperature in a production area, and then transported to a destination by an LPG carrier over a long distance.

As an engine fuel in a conventional LPG carrier, an oil fuel such as HFO (Heavy Fuel Oil) or MDO (Marine Diesel Oil) is used. In addition, conventional LPG carriers store and transport LPG as cargo in a storage tank, but BOG (Boil Off Gas) generated in the storage tank is reliquefied in a reliquefaction plant and then stored again. It is transferred to a tank and stored.

As described above, in the conventional LPG carrier, there is no means such as an engine in which fuel and cargo are used or processed in two systems and LPG stored in a storage tank as cargo can be used as fuel.

In recent years, there has been increasing interest in a method of supplying LPG stored in a storage tank as cargo as fuel for an engine.

The present invention supplies fuel for ships by supplying a non-compressible fluid as fuel for an engine and preventing a phenomenon in which a large amount of flash gas is generated when the excess liquefied gas discharged from the engine is returned to a storage tank. Provide systems and fuel delivery methods.

In order to achieve the above object, in one embodiment of the present invention, a pump that pressurizes the liquefied gas discharged from the storage tank to the required pressure of the engine and a pump that heats the liquefied gas pressurized by the pump to the required temperature of the engine. A heat exchanger that heats by exchange and a buffer tank that temporarily stores the liquefied gas discharged from the storage tank and passed through the pump and the heat exchanger and supplies the gas to the engine are provided, and a gas supply line is provided. For ships, the internal pressure of the buffer tank is adjusted by supplying the liquefied gas to the buffer tank via the buffer tank, and an amount of liquefied gas required by the engine is supplied from the buffer tank to the engine. Fuel supply system is provided.

It is preferable to further provide a return line in which the liquefied gas inside the buffer tank is returned to the storage tank by raising the water level inside the buffer tank.

It is preferable to further include a vent line that sends the gas inside the buffer tank to the storage tank.

It is preferable to further include a vent line that sends the gas inside the buffer tank to the vent master.

The marine fuel supply system further includes a water level sensor for measuring the water level of the liquefied gas inside the buffer tank and a third valve installed on the return line, and the third valve is the water level sensor. It is preferable to adjust the flow rate of the liquefied gas discharged from the valve tank according to the water level value measured in.

It is preferable that the third valve is closed in normal times and is opened when the water level value measured by the water level sensor becomes equal to or higher than the second set value.

The marine fuel supply system preferably further includes a third pressure sensor that measures the internal pressure of the buffer tank.

The marine fuel supply system further comprises a fifth valve installed on the gas supply line, which regulates the flow rate of the fluid according to the pressure value measured by the third pressure sensor. It is preferable to do so.

The marine fuel supply system further comprises a fourth valve installed on the vent line, which regulates the flow rate of the fluid according to the pressure value measured by the third pressure sensor. Is preferable.

The marine fuel supply system preferably further includes a first filter that filters impurities contained in the liquefied gas supplied to the engine.

The first filter is preferably installed between the heat exchanger and the buffer tank.

In another embodiment of the present invention to achieve the above object, in a method for supplying fuel for a ship in which a liquefied gas is compressed and heated and then supplied to an engine, the compressed and heated liquefied gas is temporarily stored in a buffer tank. The step of supplying the liquefied gas in the amount required by the engine from the buffer tank to the engine, and the step of supplying the liquefied gas inside the buffer tank to the engine by raising the water level inside the buffer tank. A method of supplying fuel for a ship is provided, which comprises a step of returning to a storage tank.

It is preferable to further include a step of sending the gas inside the buffer tank to the storage tank.

It is preferable to further include a step of sending the gas inside the buffer tank to the vent master.

INDUSTRIAL APPLICABILITY The present invention can stably supply fuel to an engine even when a liquid incompressible fluid is supplied as fuel for the engine.

In one embodiment of the present invention, by installing a buffer tank upstream of the engine, it is possible to prevent a phenomenon in which a large amount of flash gas is generated. As a result, it is possible to omit the addition of a device for processing a large amount of flash gas and the installation of a control system, and it is not necessary to design a large volume of the storage tank for accommodating the flash gas.

It is the schematic of the fuel supply system for a ship which concerns on 1st Embodiment of this invention. It is the schematic of the fuel supply system for a ship which concerns on 2nd Embodiment of this invention. It is the schematic of the fuel supply system for a ship which concerns on 3rd Embodiment of this invention.

Hereinafter, the configuration and operation of the embodiment of the present invention will be described in detail with reference to the drawings. The following embodiments can be changed to various other embodiments, and the scope of the technical idea of the present invention is not limited by the following embodiments.

FIG. 1 is a schematic view of a fuel supply system for ships according to the first embodiment of the present invention. With reference to FIG. 1, the marine fuel supply system of the present embodiment includes a pump (10), a heat exchanger (20), a first pressure sensor (P1), a first valve (V1), and a second pressure sensor. (P2) and a second valve (V2) are provided.

The storage tank (T) stores the liquefied gas, and the liquefied gas discharged from the storage tank (T) is supplied to the engine (E) as fuel. The engine (E) is a DF (Dual Fuel) engine that uses liquefied petroleum gas (LPG) and diesel (Diesel) as fuel.

The pump (10) pressurizes the liquefied gas discharged from the storage tank (T) to the required pressure of the engine (E). The heat exchanger (20) heats the liquefied gas pressurized by the pump (10) by heat exchange to the required temperature of the engine (E).

The first pressure sensor (P1) is installed on the fuel supply line (F1) that supplies the liquefied gas heated by the heat exchanger (20) to the engine (E), and measures the pressure of the fuel supply line (F1). taking measurement. The first valve (V1) is installed on the fuel supply line (F1) and opens and closes according to the pressure value measured by the first pressure sensor (P1) to adjust the flow rate of the liquefied gas.

When the load on the engine (E) decreases and the amount of fuel required by the engine (E) decreases, the amount of liquefied gas consumed decreases and the pressure in the fuel supply line (F1) increases. The first pressure sensor (P1) transmits the pressure value increased in the fuel supply line (F1) to the first valve (V1), and the first valve (V1) sends the pressure value increased from the first pressure sensor (P1) to the fuel supply line (P1). Upon receiving the increased pressure value in F1), the first valve (V1) lowers the opening degree to reduce the flow rate of the liquefied gas.

Further, when the load of the engine (E) increases and the amount of fuel required by the engine (E) increases, the amount of liquefied gas consumed increases and the pressure of the fuel supply line (F1) decreases. do. The first pressure sensor (P1) transmits the pressure value lowered in the fuel supply line (F1) to the first valve (V1), and the first valve (V1) sends the pressure value lowered from the first pressure sensor (P1) to the fuel supply line (P1). Upon receiving the reduced pressure value in F1), the first valve (V1) increases the opening degree to increase the flow rate of the liquefied gas.

A first filter (31) for filtering impurities contained in the liquefied gas supplied to the engine (E) is installed upstream of the engine (E). The first filter (31) is preferably installed between the heat exchanger (20) and the first valve (V1).

Of the liquefied gas supplied to the engine (E), the surplus liquefied gas remaining unused in the engine (E) is sent to the storage tank (T) again. In the present embodiment, after supplying an amount of liquefied gas exceeding the amount required by the engine (E) to the engine (E), the liquefied gas remaining unused in the engine (E) is supplied from the engine (E). Discharge and return to the storage tank (T).

When supplying a gaseous Compressible Fluid as fuel for the engine (E), the fuel supply line (F1) should be filled with a pressure slightly higher than the amount required by the engine (E). , The fuel, which is a compressible fluid, exists in the fuel supply line (F1) in a state of being compressed to some extent. As a result, even if the engine (E) suddenly needs a large amount of fuel, the fuel can be supplied immediately, so that the fuel can be stably supplied even if the load of the engine (E) fluctuates. can.

However, when a liquid incompressible fluid is supplied as fuel for the engine (E), the volume of the incompressible fluid changes only slightly even when pressure is applied, so the fuel supply line ( It is not possible to use a method of filling F1) with a pressure slightly higher than the amount required by the engine (E).

Further, when the engine (E) suddenly requires a large amount of fuel, the engine (E) cannot supply the required amount of fuel, and cavitation or the like occurs in the engine (E). There is a risk.

Therefore, the inventors of the present invention have determined that it is better to supply a larger amount of fuel than the engine requires, rather than to cause a case where the fuel supplied to the engine (E) is insufficient.

In the present embodiment, not only the amount of liquefied gas required by the engine (E) is supplied to the engine (E), but a sufficient amount of liquefied gas that can cope with the load fluctuation of the engine (E) is supplied to the engine (E). ), And the excess liquefied gas remaining unused in the engine (E) is discharged from the engine (E).

Therefore, in the present invention, even when a liquid incompressible fluid is supplied as fuel for the engine, the fuel can be stably supplied to the engine.

In the present embodiment, about 100% to 120% of the liquefied gas required by the engine (E) is supplied to the engine (E), and preferably about 110% of the liquefied gas required by the engine (E) is supplied to the engine. Supply to (E).

The second pressure sensor (P2) is installed on the fuel discharge line (F2) that sends the excess liquefied gas discharged from the engine (E) to the storage tank (T), and measures the pressure of the fuel discharge line (F2). do. The second valve (V2) is installed on the fuel discharge line (F2) and adjusts the flow rate of the liquefied gas so that the pressure value measured by the second pressure sensor (P2) is equal to or less than the first set value. .. The pressure of the high-pressure excess liquefied gas pressurized to the required pressure of the engine (E) is reduced by the second valve (V2) when it is returned to the storage tank (T).

A second filter (32) for filtering impurities contained in the excess liquefied gas discharged from the engine (E) is installed downstream of the engine (E). The second filter (32) is preferably installed between the second valve (V2) and the storage tank (T).

A first knockout drum (41) is installed between the engine (E) and the second valve (V2). A second knockout drum (42) is installed between the second valve (V2) and the storage tank (T).

The Knock Out Drum (KO Drum) drains only gaseous fuel through the Knock Out Drum to store other fuels or storage tanks (KO Drum) when it is necessary to drain fuel in an emergency. It plays the role of a buffer to return to T).

The gas discharged from the first knockout drum (41) and the second knockout drum (42) is sent to the Vent Master.

On the other hand, the flash gas generated by decompressing the excess liquefied gas discharged from the engine (E) by the second valve (V2) can be supplied to the reliquefaction system for reliquefaction.

FIG. 2 is a schematic view of a fuel supply system for a ship according to a second embodiment of the present invention.

With reference to FIG. 2, the marine fuel supply system of the present embodiment is a pump that pressurizes the liquefied gas discharged from the storage tank (T) to the required pressure of the engine (E), as in the first embodiment. (10) and a heat exchanger (20) that heats the liquefied gas pressurized by the pump (10) to the required temperature of the engine (E) by heat exchange. The liquefied gas heated by the heat exchanger (20) is supplied to the engine (E). Further, upstream of the engine (E), a first filter (31) for filtering impurities contained in the liquefied gas supplied to the engine (E) is installed as in the first embodiment.

However, the ship fuel supply system of the present embodiment is further provided with a buffer tank (50) and is not provided with a first pressure sensor (P1) and a first valve (V1) as compared with the first embodiment. Is different.

The buffer tank (50) temporarily stores the liquefied gas discharged from the storage tank (T) and passed through the pump (10) and the heat exchanger (20), and supplies the liquefied gas to the engine (E). In the first embodiment, a sufficient amount of liquefied gas that can cope with the load fluctuation of the engine (E) is supplied to the engine (E), and the surplus liquefied gas that remains unused in the engine (E) is used in the engine (E). In the present embodiment, the amount of liquefied gas required by the engine (E) is supplied from the buffer tank (50) to the engine (E), and the load on the engine (E) is reduced. Subsequently, the water level inside the buffer tank (50) rises, so that the liquefied gas inside the buffer tank (50) is returned to the storage tank (T) by the return line (F4).

A water level sensor (L) for measuring the water level of the liquefied gas inside the buffer tank (50) is installed in the buffer tank (50). On the return line (F4) that returns the excess liquefied gas left unused in the engine (E) from the buffer tank (50) to the storage tank (T), a third valve (F4) that adjusts the flow rate of the fluid by opening and closing it ( V3) is installed.

The third valve (V3) is opened and closed according to the water level value inside the buffer tank (50) measured by the water level sensor (L) to reduce the flow rate of the liquefied gas discharged from the buffer tank (50). Adjust. The third valve (V3) is maintained in a closed state during normal operation. When the water level value inside the buffer tank (50) measured by the water level sensor (L) becomes equal to or higher than the second set value, the third valve (V3) is opened and the liquefied gas inside the buffer tank (50) is released. It is sent to the storage tank (T).

The internal pressure of the buffer tank (50) is maintained and adjusted by supplying a gas such as nitrogen (N _{2) to the inside of the buffer tank (50).} By maintaining and adjusting the internal pressure of the buffer tank (50), the liquefied gas at the pressure required by the engine (E) can be supplied as fuel, so that the first pressure sensor can be used as in the first embodiment. It is not necessary to adjust the pressure of the liquefied gas sent to the engine (E) by the (P1) and the first valve (V1). Therefore, in this embodiment, it is not necessary to install the first pressure sensor (P1) and the first valve (V1) installed in the first embodiment.

A third pressure sensor (P3) for measuring the internal pressure of the buffer tank (50) is installed in the buffer tank (50). The opening and closing of the vent line (F5) that discharges the gas inside the buffer tank (50) (including gas such as nitrogen supplied to maintain and regulate the internal pressure, evaporative gas, and flush gas). A fourth valve (V4) that regulates the flow rate of the gas is installed. A fifth valve (V5) that adjusts the flow rate of the fluid by opening and closing the gas supply line (F3) that supplies a gas such as nitrogen to the buffer tank (50) is installed.

The fourth valve (V4) and the fifth valve (V5) are inside the buffer tank (50) measured by the third pressure sensor (P3) so that the internal pressure of the buffer tank (50) is maintained within a certain range. The flow rate of the fluid is adjusted by opening and closing according to the pressure value. By adjusting the opening / closing degree of the 4th valve (V4), the gas inside the buffer tank (50) can be sent to the storage tank (T) by the vent line (F5), and the opening / closing of the 5th valve (V5) can be performed. By adjusting the degree, a gas such as nitrogen can be supplied to the buffer tank (50). The fifth valve (V5) is maintained in an open state in normal times, and the degree of opening and closing is adjusted.

When the marine fuel supply system of the present embodiment includes the first filter (31), the first filter (31) is preferably installed between the heat exchanger (20) and the buffer tank (50). ..

In the first embodiment, when the high-pressure excess liquefied gas pressurized to the required pressure of the engine (E) is returned to the storage tank (T), the pressure of the liquefied gas suddenly reaches the internal pressure of the storage tank (T). There is a problem that a large amount of flash gas is generated due to the decrease. When a large amount of flash gas is generated, it is necessary to design each volume of the storage tank (T), knockout drum (41, 42), vent master, etc. to be large enough to accommodate the flash gas, and a large amount of flash gas. An additional device or control system is required to process the gas.

In the present embodiment, the buffer tank (50) is installed, and in order to supply the amount of liquefied gas required by the engine (E) from the buffer tank (50), the pressure is increased to the required pressure of the engine (E). The situation where the liquefied gas is sent to the storage tank (T) does not occur, and the phenomenon that a large amount of flash gas is generated can be prevented.

Therefore, in this embodiment, the installation of additional devices such as knockout drums (41, 42), vent master, and control system can be omitted in order to process a large amount of flash gas, and the flash gas is stored to be accommodated. There is an advantage that it is not necessary to design the volume of the tank (T) to be large.

FIG. 3 is a schematic view of a fuel supply system for ships according to a third embodiment of the present invention.

With reference to FIG. 3, the marine fuel supply system of the present embodiment produces the gas discharged from the buffer tank (50) as compared with the marine fuel supply system of the second embodiment shown in FIG. The difference is that it is sent to the vent master instead of being sent to the storage tank (T) via the vent line (F5), and the roles of the other members and the effects associated therewith are the same as in the second embodiment.

Since the gas discharged from the buffer tank (50) is not sent to the storage tank (T), the present embodiment has an advantage that the volume of the storage tank (T) can be designed to be smaller than that of the second embodiment. be.

It is obvious to those skilled in the art in the technical field to which the present invention belongs that the present invention is not limited to the above-described embodiment and can be variously modified or modified within a range not exceeding the technical gist of the present invention.

Claims (14)

A pump that pressurizes the liquefied gas discharged from the storage tank to the required pressure of the engine;
A heat exchanger that heats the liquefied gas pressurized by the pump to the required temperature of the engine by heat exchange;
A buffer tank that temporarily stores the liquefied gas discharged from the storage tank and passed through the pump and the heat exchanger and supplies the liquefied gas to the engine;
By supplying gas to the buffer tank via the gas supply line, the internal pressure of the buffer tank is adjusted.
A fuel supply system for ships, characterized in that an amount of liquefied gas required by the engine is supplied from the buffer tank to the engine. The fuel supply for a ship according to claim 1, further comprising a return line in which the liquefied gas inside the buffer tank is returned to the storage tank by raising the water level inside the buffer tank. system. The fuel supply system for a ship according to claim 2, further comprising a vent line for sending the gas inside the buffer tank to the storage tank. The fuel supply system for a ship according to claim 2, further comprising a vent line for sending the gas inside the buffer tank to the vent master. A water level sensor for measuring the water level of the liquefied gas inside the buffer tank; and a third valve installed on the return line;
The third valve according to any one of claims 2 to 4, wherein the third valve adjusts the flow rate of the liquefied gas discharged from the buffer tank according to the water level value measured by the water level sensor. Fuel supply system for ships. The fuel supply for a ship according to claim 5, wherein the third valve is in a closed state in normal times and is opened when the water level value measured by the water level sensor becomes equal to or higher than the second set value. system. The fuel supply system for a ship according to any one of claims 1 to 4, further comprising a third pressure sensor for measuring the internal pressure of the buffer tank. Further equipped with a fifth valve installed on the gas supply line
The fuel supply system for a ship according to claim 7, wherein the fifth valve adjusts the flow rate of the fluid according to the pressure value measured by the third pressure sensor. Further equipped with a fourth valve installed on the vent line
The fuel supply system for a ship according to claim 7, wherein the fourth valve adjusts the flow rate of the fluid according to the pressure value measured by the third pressure sensor. The fuel supply system for a ship according to any one of claims 1 to 4, further comprising a first filter for filtering impurities contained in the liquefied gas supplied to the engine. The fuel supply system for a ship according to claim 10, wherein the first filter is installed between the heat exchanger and the buffer tank. In a marine fuel supply method in which liquefied gas is compressed and heated and then supplied to an engine.
Steps to temporarily store compressed and heated liquefied gas in a buffer tank,
A step of supplying the engine with the amount of liquefied gas required by the engine from the buffer tank.
A method for supplying fuel for a ship, which comprises a step of returning the liquefied gas inside the buffer tank to a storage tank by raising the water level inside the buffer tank. The method for supplying fuel for a ship according to claim 12, further comprising a step of sending the gas inside the buffer tank to the storage tank. The method for supplying fuel for a ship according to claim 12, further comprising a step of sending the gas inside the buffer tank to the vent master.

Images