KR20220099163A - Fuel Supply System And Method For Ship - Google Patents

Abstract

A fuel supply system and a method for a ship are disclosed. The fuel supply system for a ship of the present invention includes: a fuel supply line for supplying liquefied gas from a storage tank provided in a ship to a fuel consumption place in the ship; a forced vaporizer provided in the fuel supply line to vaporize the liquefied gas; a particle separator for receiving the liquefied gas vaporized in the forced vaporizer and separating the same into gas and liquid; a drain line for recovering the liquid separated by the particle separator to the storage tank; a drain pot provided below the particle separator in the drain line and accommodating liquid to be separated from the particle separator and returned to the storage tank; and an eductor provided on the drain line and transferring the liquid contained in the drain pot to the storage tank, thereby capable of preventing devices from being damaged and supplying fuel stably while smoothly recovering the separated liquid to the tank.

Description

Fuel Supply System And Method For Ship

The present invention provides a fuel supply system for a ship that allows the liquid separated from the forcibly vaporized liquefied gas in a particle separator to be smoothly recovered to the storage tank while supplying fuel to a fuel consumer in the ship by forcibly vaporizing the liquefied gas from the ship's storage tank. and methods.

Natural gas is a fossil fuel containing methane as a main component and a small amount of ethane, propane, and the like, and has recently been spotlighted as a low-pollution energy source in various technological fields.

Natural gas is widely consumed as an economical and eco-friendly energy, but transport and storage efficiency is low due to its large volume to be transported in the gaseous natural gas state.

In order to supplement this point, a method of transporting and storing liquefied natural gas (LNG) in the state has been proposed. Liquefied natural gas is a colorless and transparent cryogenic liquid whose volume is reduced to 1/600 by cooling natural gas containing methane as its main component from atmospheric pressure to a cryogenic state of -162°C.

However, since the liquefaction temperature of natural gas is a cryogenic temperature of -162°C under normal pressure, LNG is sensitive to temperature changes and evaporates easily. Although the LNG storage tank of an LNG carrier is insulated, external heat is continuously transferred to the LNG storage tank. Boil-Off Gas (BOG) is generated in the storage tank.

BOG is a kind of LNG loss and is an important problem in the transport efficiency of LNG. If boil-off gas is accumulated in the LNG storage tank, the pressure in the LNG storage tank increases excessively and there is a risk of the tank being damaged. Various methods are being studied to deal with it.

Recently, for the treatment of BOG, a method of re-liquefying BOG and returning it to a storage tank, a method of using BOG as an energy source of a ship's engine, etc. are used. And for the surplus BOG, a method of burning in a gas combustion unit (GCU) is used.

In addition, a dual fuel engine that can use natural or forced gas and fuel oil in the propulsion device or power generation device of the LNG carrier itself as fuel has been developed and is being used as the main engine and generator engine. It is also supplied as onboard fuel.

A DF engine, an X-DF engine, a ME-GI engine, etc. are representative examples of BOG, that is, a marine engine that can use natural gas as a fuel.

The DF engine (DFDE, DFGE) is composed of 4 strokes, and adopts an Otto Cycle that injects natural gas with a relatively low pressure of 5.5 barg into the combustion air inlet and compresses it as the piston rises. are doing

The X-DF engine is composed of two strokes, uses 12 to 15 barg of natural gas as a fuel, and adopts an auto cycle.

The ME-GI engine is composed of two strokes, and adopts a diesel cycle in which high-pressure natural gas near 300 barg is directly injected into the combustion chamber near top dead center of the piston.

1 schematically shows an example of a fuel supply system for a ship.

As shown in Figure 1, the liquefied gas of the cargo tank is forcibly vaporized in the forced vaporizer 10, and the liquefied gas transferred from the stripping header 70 in the in-line mixer 20 is sprayed and then to the mist separator 30. transport

The gas separated in the mist separator 30 is supplied to fuel such as an onboard engine through the compressor 40, and the separated liquid is sent to the drain pot 50 under the mist separator by gravity and recovered to the cargo tank.

The control unit 60 controls each valve Va, Vb, Vc, and Vd according to the level of the drain pot sensed by the level sensor LT, so that the liquid separated from the mist separator is applied to the height difference between the mist separator and the cargo tank. It is recovered to the cargo tank through the drain pot without a separate supply device. However, the liquid separated from the mist separator is difficult to be smoothly recovered to the cargo tank due to its high viscosity, and when the liquid level in the drain pot rises above a certain height, nitrogen is supplied to purging to prevent damage to the device.

The present invention is to solve this problem and to propose a method for preventing damage to the device and stably supplying fuel while smoothly recovering the separated liquid to the tank.

According to an aspect of the present invention for solving the above-described problems, a fuel supply line for supplying liquefied gas from a storage tank provided on a ship to a fuel consumer in the ship;

a forced vaporizer provided in the fuel supply line to vaporize the liquefied gas;

a particle separator for receiving the liquefied gas vaporized from the forced vaporizer and separating it into gas and liquid;

a drain line for recovering the liquid separated in the particle separator to the storage tank;

a drain pot provided at a lower portion of the particle separator in the drain line and accommodating the liquid to be separated from the particle separator and recovered to the storage tank; and

An eductor provided in the drain line and transferring the liquid accommodated in the drain pot to the storage tank is provided.

Preferably, an in-line mixer provided in the fuel supply line and transferred to the particle separator by injecting the liquefied gas transferred from the stripping header provided in the storage tank to the liquefied gas vaporized in the forced vaporizer; and a working fluid supply line for supplying a working fluid to the eductor: the liquefied gas supplied from the stripping header to the in-line mixer may be branched and supplied as a working fluid to the eductor.

Preferably, a compressed gas supply line for purging the drain pot by supplying a portion of the gas compressed in the compressor for compressing the fuel to be supplied to the onboard fuel consumer to the drain pot; and a purging line for purging the drain pot by supplying nitrogen gas to the drain pot.

Preferably, a pressure sensor provided in the compressed gas supply line to sense the pressure at the rear end of the compressor; a first non-return valve provided in the compressed gas supply line; and a second non-return valve provided in the purging line, wherein the compressed gas supply line joins the purging line at the rear end of the second non-return valve and is connected to the drain pot, and is sensed by the pressure sensor A portion of the gas compressed in the compressor or nitrogen gas may be supplied to the drain pot for purging according to the pressure at the end of the compressor.

Preferably, a level sensor for detecting the level of the drain pot; and a drain pot sequence controller configured to control supply of liquid from the particle separator to the drain pot and gas supply for purging the drain pot according to the level of the drain pot detected by the level sensor.

Preferably, a vent line for discharging the gas of the drain pot to the outside; a breathing line connected to the particle separator at an upper portion of the drain pot; a first valve provided between the particle separator and the drain pot in the drain line; a second valve provided in the vent line; a third valve provided on the breathing line; a fourth valve provided downstream of the junction of the compressed gas supply line in the purging line; and a fifth valve provided between the drain pot and the eductor in the drain line.

Preferably, a sixth valve provided in the working fluid supply line; and a level controller that controls the sixth valve according to the level of the drain pot detected by the level sensor to adjust the working fluid supplied to the eductor.

According to another aspect of the present invention, liquefied gas is forcibly vaporized from a storage tank provided on a ship, and the forcibly vaporized liquefied gas is separated from gas and liquid in a particle separator, and the separated gas is supplied to a fuel consumer on board,

The liquid separated in the particle separator is transferred to a drain pot provided under the particle separator and recovered to the storage tank,

An eductor is provided at the rear end of the drain pot to provide a fuel supply method for a ship, characterized in that the liquid accommodated in the drain pot is transferred to the storage tank.

Preferably, by sensing the pressure at the end of the compressor for compressing the fuel to be supplied to the onboard fuel consumer, and supplying a part of the gas compressed in the compressor or nitrogen gas to the drain pot according to the sensed pressure at the end of the compressor, the drain pot can be purged.

Preferably, the liquefied gas transferred from the stripping header provided in the storage tank may be supplied to the eductor as a working fluid.

In the present invention, an eductor is provided at the rear end of the drain pot so that the highly viscous liquid separated from the particle separator can be smoothly recovered to the storage tank.

That is, an eductor is provided that utilizes the liquefied gas transferred from the stripping header and transferred to the in-line mixer as a working fluid, and the fuel gas compressed at the rear end of the compressor can be used for purging the drain pot, thereby reducing the liquid level of the drain pot and the particle separator. can be maintained, and damage to the device can be prevented.

1 schematically shows an example of a fuel supply system for a ship.
2 schematically shows a fuel supply system for a ship according to an embodiment of the present invention.
3 is a flowchart illustrating a drain pot sequence control method according to an embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objects achieved by the practice of 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 configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, in adding reference signs to the elements of each drawing, it should be noted that only the same elements are indicated by the same reference numerals as much as possible even though they are indicated on different drawings.

The liquefied gas in the embodiment to be described later may be transported by being liquefied at a low temperature, and may be applied to all kinds of liquefied gas that can be supplied as fuel to devices such as inboard engines, generators, and boilers. Such liquefied gas is, for example, liquefied gas such as LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), Liquefied Ethylene Gas, Liquefied Propylene Gas, etc. can However, in the embodiments to be described later, LNG, which is a representative liquefied gas, will be described as an example.

FIG. 2 schematically shows a fuel supply system for a ship according to an embodiment of the present invention, and FIG. 3 is a flowchart illustrating a drain pot sequence control method in the embodiment of the present invention.

As shown in FIG. 2, the fuel supply system of this embodiment separates and stores the liquid contained in the forcibly vaporized liquefied gas while forcibly vaporizing the liquefied gas from the storage tank provided on the ship and supplying it to the onboard fuel consumer 300. As a system for recovering to a tank, the fuel supply line (FL) connected from the storage tank to the fuel consuming place 300 such as the engine, the forced carburetor 100 provided in the fuel supply line to vaporize the liquefied gas, and the forced carburetor vaporize A particle separator 200 that receives the supplied liquefied gas and separates it into gas and liquid, a drain line (DL) that recovers the liquid separated from the particle separator into a storage tank, and a drain line provided at the bottom of the particle separator and separated from the particle separator It is characterized in that it includes a drain pot 400 for accommodating the liquid to be recovered to the storage tank, and in particular, is provided in the drain line and includes an eductor 500 for transferring the liquid accommodated in the drain pot to the storage tank.

The fuel supply line (FL) is provided with an in-line mixer 600 and injects the liquefied gas transferred from the stripping header 150 provided in the storage tank to the liquefied gas vaporized in the forced vaporizer 100 and transferred to the particle separator 200. . In the in-line mixer 600, the liquefied gas transferred from the stripping header is injected into the liquefied gas vaporized through the forced vaporizer, and impurities, unvaporized gas, etc. contained in the forced vaporized gas are converted to fuel in the particle separator in a mist state. It must be separated from the gas to be supplied. In the present embodiment system, the liquefied gas supplied from the stripping header 150 to the inline mixer 600 is branched and supplied to the working fluid of the eductor 500 through the working fluid supply line ML. The droplets recovered from the particle separator to the drain pot have high viscosity, but can be smoothly recovered from the drain pot to the storage tank by providing an eductor using liquefied gas as the working fluid. In addition, since liquefied gas is used as the working fluid of the eductor, there is no risk of contamination of the liquefied gas in the tank.

On the other hand, in this embodiment, a compressed gas supply line (CL) for purging the drain pot by supplying a part of the gas compressed in the compressor 350 for compressing the fuel to be supplied to the onboard fuel consumer to the drain pot 400 is A purging line PL is provided for purging the drain pot by supplying nitrogen gas to the drain pot. In addition, the compressed gas supply line is provided with a pressure sensor (PT) for sensing the rear end pressure of the compressor, the compressed gas supply line is provided with a first non-return valve (CV1), and the purging line is provided with a second non-return valve (CV2), respectively. provided, the compressed gas supply line CL joins the purging line PL at the rear end of the second non-return valve CV2 and is connected to the drain pot 400 .

According to the pressure at the rear end of the compressor 350 detected by the pressure sensor PT, a part of the compressed gas or nitrogen gas may be supplied to the drain pot for purging. The compressed high-pressure fuel gas is sent to the drain pot to purify the drain pot, and when the pressure detected by the pressure sensor is low, nitrogen gas is supplied to the drain pot to purify. In the present embodiment, the drain pot can be smoothly purged using the high-pressure fuel gas as described above, and the reverse flow of nitrogen gas to the rear end of the compressor can be prevented by providing the first and second non-return valves.

In this embodiment, a level sensor (LT) for detecting the level of the drain pot, a drain for controlling the supply of liquid from the particle separator to the drain pot and gas supply for purging the drain pot according to the level of the drain pot detected by the level sensor A vent line VL including a pot sequence control unit 700 and discharging the gas of the drain pot to the outside, and a breathing line BL connected to the particle separator at an upper portion of the drain pot are provided.

In the drain line DL, a first valve V1 is provided between the particle separator and the drain pot, a second valve V2 is provided in the vent line VL, and a third valve V3 is provided in the breathing line BL. In addition, a fourth valve V4 downstream of the junction of the compressed gas supply line CL in the purging line PL, a fifth valve V5 between the drain pot and the eductor in the drain line DL, and a working fluid supply A sixth valve V6 is provided in the line ML, and a seventh valve V7 for opening and closing the supply of nitrogen gas is provided upstream of the junction of the compressed gas supply line in the purging line PL.

The drain pot sequence control unit 700 controls the first to fourth valves and the seventh valves according to the level of the drain pot detected by the level sensor LT and the pressure at the rear end of the compressor detected by the pressure sensor PT, so that in the particle separator Controls the supply of liquid to the drain pot and gas supply for purging the drain pot, and the level controller (LIC) controls the sixth valve (V6) according to the level of the drain pot detected by the level sensor (LT). Controls the working fluid supplied to the generator (500).

3 is a flowchart of a control method by the drain pot sequence controller in the present embodiment. Basically, the first valve V1 and the fifth valve V5 are operated in an open state so that the liquid separated from the particle separator is recovered to the storage tank through the drain pot. When the level of the drain pot detected by the level sensor (LT) increases because it is not smoothly recovered to the storage tank, an alarm of the level sensor sounds, and the drain pot is discharged by fuel gas or nitrogen gas according to the control of the drain pot sequence control unit 700 . The liquid in the drain pot is transferred to the storage tank by purging, which can be controlled as in the sequence of FIG. 3 .

When the level of the drain pot detected by the level sensor rises or the drain pot sequence controller starts control according to the manual, the first and third valves are closed first to prevent the liquid separated from the particle separator from being transferred to the drain pot. . Thereafter, the fifth valve at the rear end of the drain pot of the drain line is opened so that the liquid accommodated in the drain pot is transferred to the storage tank through the eductor, and the fourth valve is opened to purify the drain pot.

According to the pressure at the rear end of the compressor detected by the pressure sensor, the detected pressure value and the pressure set value are compared. If the detected pressure value at the end of the compressor is lower than the pressure set value, the 7th valve is opened to supply additional nitrogen gas to close the drain pot. Purging.

If the detected pressure value at the rear end of the compressor is higher than the pressure set value, the level of the level sensor is compared with the set value. After opening and venting the drain pot, the second valve is closed, and the first and third valves are opened to resume liquid transfer from the particle separator to the drain pot. When the level of the drain pot detected by the level sensor is higher than the set value, if the 7th valve is closed depending on whether the 7th valve is opened or closed, the pressure value at the rear end of the compressor detected by the pressure sensor is compared with the set pressure value, and the fuel gas Alternatively, the drain pot is purged with nitrogen. When the 7th valve is open or in case of an error in each step, the sequence control is performed by operating to the failsafe position to close the 2nd, 4th and 7th valves, and then opening the 1st and 3rd valves from the failsafe position. quit

The present invention is not limited to the above embodiments, and it is apparent to those skilled in the art that various modifications or variations can be implemented without departing from the technical gist of the present invention. did it

FL: fuel supply line
DL: drain line
ML: Working fluid supply line
PL: Purging line
CL: compressed gas supply line
100: forced carburetor
150: stripping header
200: particle separator
300: fuel consumer
350: compressor
400: drain pot
500: eductor
600: inline mixer
V1, V2, V3, V4, V5, V6, V7: first to seventh valves
CV1, CV2: first and second non-return valve

Claims (10)

a fuel supply line for supplying liquefied gas from a storage tank provided on a ship to a fuel consumer on board;
a forced vaporizer provided in the fuel supply line to vaporize the liquefied gas;
a particle separator for receiving the liquefied gas vaporized from the forced vaporizer and separating it into gas and liquid;
a drain line for recovering the liquid separated in the particle separator to the storage tank;
a drain pot provided at a lower portion of the particle separator in the drain line and accommodating the liquid to be separated from the particle separator and recovered to the storage tank; and
An eductor provided in the drain line and configured to transfer the liquid accommodated in the drain pot to the storage tank. The method of claim 1,
an in-line mixer provided in the fuel supply line and transferred to the particle separator by injecting the liquefied gas transferred from the stripping header provided in the storage tank to the liquefied gas vaporized in the forced vaporizer; and
Further comprising: a working fluid supply line for supplying a working fluid to the eductor,
A fuel supply system for a ship, characterized in that the liquefied gas supplied from the stripping header to the in-line mixer is branched and supplied to the eductor as a working fluid. 3. The method of claim 2,
a compressed gas supply line for purging the drain pot by supplying a portion of the gas compressed in the compressor for compressing the fuel to be supplied to the onboard fuel consumer to the drain pot; and
A purging line for purging the drain pot by supplying nitrogen gas to the drain pot. 4. The method of claim 3,
a pressure sensor provided in the compressed gas supply line to sense the pressure at the rear end of the compressor;
a first non-return valve provided in the compressed gas supply line; and
A second non-return valve provided in the purging line further comprises:
The compressed gas supply line joins the purging line at the rear end of the second non-return valve and is connected to the drain pot, and according to the pressure at the rear end of the compressor detected by the pressure sensor, a part of the gas compressed in the compressor or nitrogen gas is A fuel supply system for a ship, characterized in that it is supplied for purging to the drain pot. 5. The method of claim 4,
a level sensor sensing the level of the drain pot; and
A fuel supply system for a ship further comprising: a drain pot sequence controller configured to control supply of liquid from the particle separator to the drain pot and gas supply for purging the drain pot according to the level of the drain pot detected by the level sensor . 6. The method of claim 5,
a vent line for discharging the gas of the drain pot to the outside;
a breathing line connected to the particle separator at an upper portion of the drain pot;
a first valve provided between the particle separator and the drain pot in the drain line;
a second valve provided in the vent line;
a third valve provided on the breathing line;
a fourth valve provided downstream of the junction of the compressed gas supply line in the purging line; and
A fifth valve provided between the drain pot and the eductor in the drain line: The fuel supply system of a ship further comprising a. 6. The method of claim 5,
a sixth valve provided in the working fluid supply line; and
A fuel supply system for a ship further comprising: a level controller for controlling the sixth valve according to the level of the drain pot detected by the level sensor to adjust the working fluid supplied to the eductor. Liquefied gas is forcibly vaporized from a storage tank provided on the ship, and the forcibly vaporized liquefied gas is separated from gas and liquid in a particle separator, and the separated gas is supplied to a fuel consumer on board,
The liquid separated in the particle separator is transferred to a drain pot provided under the particle separator and recovered to the storage tank,
An eductor is provided at the rear end of the drain pot, and the liquid accommodated in the drain pot is transferred to the storage tank. 9. The method of claim 8,
Detecting a pressure at a rear end of a compressor that compresses fuel to be supplied to the onboard fuel consumer, and supplying a part of the gas compressed in the compressor or nitrogen gas to the drain pot according to the sensed pressure at the end of the compressor to purge the drain pot A method of supplying fuel to a ship. 9. The method of claim 8,
A fuel supply method for a ship, characterized in that the liquefied gas transferred from the stripping header provided in the storage tank is supplied as a working fluid to the eductor.

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