KR20220013920A - Liquefied Gas Fueled Ship and Fuel Venting System and Method - Google Patents

Abstract

The present invention relates to a system and a method for venting liquid fuel in a ship, which can stably drive an engine by quickly and smoothly discharging vented liquid fuel in supplying the liquid fuel to the liquid fuel engine of the ship which uses a low flash point liquefied gas such as LPG as fuel. The system for venting liquid fuel in a ship, according to the present invention, comprises: a service tank for storing liquid fuel; a dual fuel engine using the liquid fuel and fuel oil stored in the service tank as fuel; a fuel supply unit for supplying the liquid fuel from the service tank to the dual fuel engine; a knockout drum for recovering the liquid fuel vented from the fuel supply unit and the dual fuel engine; a heating jacket for heating and vaporizing the liquid fuel recovered in the knockout drum; and a venting line for venting the gas vaporized in the knockout drum overboard.

Description

Liquefied Gas Fueled Ship and Fuel Venting System and Method}

The present invention is a liquid fuel of a ship capable of stably driving the engine by quickly and smoothly discharging vented liquid fuel in supplying liquid fuel to a liquid fuel engine of a ship using a low flash point liquefied gas such as LPG as fuel. It relates to a venting system and method.

As international regulations to prevent air pollution have been strengthened, fuels for ships are changing, and the demand for clean fuels that do not contain sulfur is increasing. Among them, natural gas with methane as the main component is being applied as a representative fuel of the future for ships, and liquefied petroleum gas (LPG), which has propane and butane as main components, is also effective for ships. emerging as a propulsion fuel.

In addition, LPG is the first and most produced by-product in the liquefaction process of petroleum refining and natural gas, and the volume of LPG at sea is increasing. Demand is expected to increase further.

The propulsion system of a general LPG carrier is composed of a diesel engine using oil fuel such as diesel, HFO (Heavy Fuel Oil) or MDO (Marine Diesel Oil). A ship has been proposed.

Two-stroke engines applied as engines for ships are traditionally operated with liquid fuels such as fuel oil, but as concerns about the environment have increased, they have developed into dual-fuel engines that can also be operated with alternative fuels such as gas, methanol, etc. have. In particular, the concentration of environmental pollutants such as SOx, NOx, and CO ₂ in exhaust gas is significantly lower when low flash point fuels such as methanol, ethanol, and LPG are used as fuel for two-stroke engines, compared to when heavy oil is used as fuel. to be.

Because these low flash point fuels have a low flash point, they cause serious problems if they leak into one of the other parts of the engine and mix with other fluids, such as lubricating oil systems. Low flash point fuels are inherently susceptible to ignition and their vapors can readily form explosive mixtures. Therefore, if the low flash point fuel enters other parts of the engine, the engine must be stopped for safety reasons and all liquids in the device must be cleaned or replaced, which is costly and cumbersome for the engine user.

As such, the known gas fuel supply system for two-stroke engines is low such that when operating on LPG or any similar low flash point fuel, which has a relatively high compressibility, the valves, piping, etc., must also be equipped in consideration of the high pressure. It is necessary to provide a separate fuel supply system for flash point fuels.

The basic LPG fuel supply system is configured to compress the LPG discharged from the LPG storage tank to the pressure required by the LPG fuel engine, heat the compressed LPG to a temperature required by the LPG fuel engine, and supply it to the LPG fuel engine. .

At this time, when the LPG fuel engine is stopped or shut down, the remaining LPG remaining on the system is discharged to the knockout drum for restarting the engine. In addition, liquid LPG discharged from the fuel supply unit or the valve train is also recovered and treated in the knockout drum.

Since the liquid LPG recovered in the knockout drum is at a high temperature, when it is recovered to the LPG storage tank, the temperature inside the LPG storage tank is increased to accelerate the generation of boil-off gas. In addition, since the LPG fuel recovered from the LPG fuel engine contains oil such as lubricating oil leaked from the engine, it is not suitable for re-liquefaction and there is a problem of contaminating the LPG in the LPG storage tank. is configured to collect and process the LPG fuel recovered when the engine is stopped in a liquid state in a separate knockout drum.

On the other hand, conventionally, it is detected using a level switch so that the LPG discharged to the knockout drum does not exceed the hold up volume. If detected, the engine is configured to not restart until the water level is lowered below that.

Although the LPG in the knockout drum is naturally vaporized as it is discharged to atmospheric pressure, it is advantageous to rapidly lower the water level in the knockout drum by venting it into a gaseous state by promoting the vaporization of the LPG in the knockout drum to quickly restart the engine.

However, since the main components of LPG are propane and butane, the heat of vaporization of propane is about 101.8 kcal/kg and the heat of vaporization of butane is about 92.1 kcal/kg, so the energy required to phase change LPG from liquid to gas is enormous.

Therefore, the present invention is to solve the above-mentioned problems, recovering liquid fuel having a high heat of vaporization characteristic to the knockout drum, and quickly vaporizing the liquid fuel recovered in the knockout drum using an existing inboard system to process it. An object of the present invention is to provide a liquid fuel venting system and method for a ship.

According to one aspect of the present invention for achieving the above object, a service tank for storing liquid fuel; a dual fuel engine using liquid fuel and fuel oil stored in the service tank as fuel; a fuel supply unit for supplying the liquid fuel from the service tank to the dual fuel engine; a knockout drum for recovering the liquid fuel vented from the fuel supply unit and the dual fuel engine; a heating jacket for heating and vaporizing the liquid fuel recovered in the knockout drum; and a venting line for venting the gas vaporized in the knockout drum outboard.

Preferably, the high-temperature coolant discharged after cooling the jacket of the dual fuel engine is supplied to the heating jacket so as to be used as a heat source for vaporizing the liquid fuel, and the low-temperature coolant cooled while vaporizing the liquid fuel is a coolant circulation line that is a flow path for supplying to the dual fuel engine so as to be recirculated to the jacket of the dual fuel engine; and a circulation pump provided in the cooling water circulation line to circulate the cooling water.

Preferably, a coolant cooler for further cooling the low-temperature coolant and supplying it to the jacket of the dual fuel engine; and a temperature control valve configured to control a flow path such that the low-temperature coolant bypasses the coolant cooler and is supplied to the jacket of the dual fuel engine.

Preferably, a fuel supply line connecting the fuel supply unit and the dual fuel engine and providing a flow path through which liquid fuel is supplied from the fuel supply unit to the dual fuel engine; an air exhaust fan for discharging air from the double pipe part in order to circulate air in the double pipe part, which is a section formed by the double pipe part of the fuel supply line; and a selection line connecting the knockout drum and the air exhaust fan, and providing a flow path through which gas is vented from the knockout drum by the air exhaust fan.

Preferably, an air venting line that connects the air exhaust fan and the double pipe part and is a flow path for air discharged from the double pipe part; and an air venting valve provided in the air venting line, which is always open when the dual fuel engine is in the liquid fuel supply mode, and is controlled to close when the gas from the knockout drum is vented by the air exhaust fan along the selection line; may include more.

Preferably, an inert gas supply device for generating an inert gas and supplying it to the purging gas of the fuel supply line; an ejector that receives the inert gas as a working fluid and is driven to vent the gas from the knockout drum outboard; and a venting line that connects the knockout drum and the ejector and provides a flow path through which gas is vented from the knockout drum by the ejector.

Preferably, the control unit for controlling the selection valve, the knockout drum, and the air exhaust fan so that the gas from the knockout drum is vented through any one or more of the air exhaust fan and the ejector; may further include.

Preferably, it includes; a level sensor for measuring the water level of the knockout drum; The control unit may control the selection valve, the knockout drum, and the air exhaust fan according to the level measurement value of the level sensor.

Preferably, a fuel recovery line providing a flow path so that the liquid fuel consumed and remaining from the dual fuel engine is recovered to the service tank; and a fuel valve train including a plurality of service valves for controlling the flow of fluid through the fuel supply line and the fuel recovery line, wherein the fuel valve train includes the fuel supply line and/or the fuel recovery line a venting valve that is opened when venting is required from the venting valve to recover liquid fuel from the fuel supply line and/or fuel recovery line to the knockout drum; and a double shut-off valve for blocking a partial section of the fuel supply line and/or fuel recovery line when venting is required from the fuel supply line and/or the fuel recovery line, and liquid fuel between the double shut-off valve is vented with a knockout drum It may include; a stop valve consisting of an outlet valve for

Preferably, the knockout drum comprises: a first drum for recovering the liquid fuel vented from the fuel supply unit; and a second drum for recovering the liquid fuel vented from the fuel supply line and the fuel recovery line.

Preferably, the liquid fuel may be LPG or ammonia.

Preferably, the dual fuel engine may be a ME-LGIP engine.

According to another aspect of the present invention for achieving the above object, when stopping the fuel supply of the liquid fuel to the dual fuel engine, a fuel supply unit for supplying the liquid fuel to the dual fuel engine, and the fuel supply unit and dual The liquid fuel remaining in the fuel supply line connecting the fuel engine and the fuel recovery line for recovering the liquid fuel from the dual fuel engine to the service tank storing the liquid fuel is vented with a knockout drum, and then to the knockout drum. A liquid fuel venting method of a ship is provided, in which the recovered liquid fuel is vented by changing the phase to a gaseous state using a vaporization promoting means.

Preferably, the vaporization accelerating means is a heating jacket for heating and vaporizing the liquid fuel, cooling the jacket of the dual fuel engine and vaporizing the liquid fuel by using the discharged high-temperature coolant as a heat source, and the liquid fuel The low-temperature coolant cooled while vaporizing fuel may be recirculated to the jacket of the dual fuel engine.

Preferably, the vaporization promoting means is an air exhaust fan for discharging air to a double pipe of the fuel supply line for air circulation, a line connected from the double pipe to the air exhaust fan is closed, and the air exhaust fan and lowering the evaporation pressure in the knockout drum to vaporize and vent the liquid fuel in the knockout drum.

Preferably, the vaporization accelerating means is an ejector for lowering the vaporization pressure of the liquid fuel by forming a vacuum level in the knockout drum, and supplies an inert gas for purging of the fuel supply line as a working fluid of the ejector, By operating it, the liquid fuel in the knockout drum can be vaporized and vented.

Preferably, the flow path of the gas discharged from the knockout drum and the air exhaust fan so that the gas is vented from the knockout drum by any one or more of the air exhaust fan and the ejector according to whether the air circulation process of the double pipe is performed; It is possible to selectively control whether the ejector is operated or not.

The liquid fuel venting system for a ship according to the present invention prevents the water level in the knockout drum from exceeding an appropriate retention amount or promotes vaporization of the liquid fuel in the knockout drum when it exceeds the water level so that the water level in the knockout drum rapidly lowers, It is possible to improve the safety of the system, and to reduce the interval between the next fuel operation of the engine that has stopped driving, so that the engine can be operated smoothly.

In addition, in vaporizing liquid fuel in the knockout drum and venting it quickly, the fuel system device of the existing ship is maximized, and by utilizing the waste heat of the engine, the additional energy required to vaporize the liquid fuel is minimized, and energy efficiency of the overall fuel supply can be improved

1 is a schematic diagram illustrating a liquid fuel venting system of a ship.

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, it should be noted that in adding reference signs to the elements of each drawing, the same elements are indicated with the same reference numerals as much as possible even though they are indicated on different drawings. In addition, the following examples may be modified in various other forms, and the scope of the present invention is not limited to the following examples.

One embodiment of the present invention to be described later may be applied to a ship, and an engine using a low flash point liquid fuel as a fuel is used as a propulsion engine and/or an engine for power generation, and the liquid fuel is stored as cargo and/or fuel. It can be applied to a ship equipped with a storage tank. In the present specification, although an LPG carrier (LPG Carrier, LPG Tanker) will be described as an example as a ship, the present disclosure is not limited thereto, and may be applied to various ships such as a general passenger ship or a container ship.

In addition, in one embodiment of the present invention, the engine, as an engine capable of using liquid gas as a fuel, will be described by taking as an example that a ME-LGI (Liquid Gas Injection) engine is applied. The ME-LGI engine is a dual-fuel engine of a high-pressure liquid gas injection type, and low flash point liquids such as methanol, ethanol, dimethylether (DME) and LPG (Liquefied Petroleum Gas) ( LFL (Low Flashpoint Liquid) can be used as fuel, and it is driven by a diesel cycle.

Unlike ME-GI engines, where fuel is injected in the gas phase, ME-LGI engines are dual fuel engines for low flash point liquid fuels. In particular, the ME-LGIP engine was designed to successfully overcome the application of a fuel having a low cetane number, such as methanol, and particularly poor quality of self-ignition.

The ME-LGI engine is a Liquid Gas Injection Methanol (ME-LGIM) engine, a liquid gas injection engine designed for methanol operation so that methanol fuel can be used, and a liquid gas injection engine designed for LPG operation so that LPG can be used as a fuel. It is classified into ME-LGIP, etc., and the design structure and fuel supply system and method must be changed according to the characteristics of the fuel.

In addition, in one embodiment of the present invention to be described later, the fuel is described as an example that is applied to an LPG fueled ship in which LPG is used, but the liquid fuel venting system and method of the ship according to an embodiment of the present invention is ammonia ( It can also be applied to ammonia-fueled ships that use ammonia) as fuel for engines.

LPG is a mixture containing propane and butane as main components, and the composition may be slightly different depending on the production area. In the present specification, LPG will be described based on about 75% of propane and butane, and about 25% of ethane.

Hereinafter, a liquid fuel venting system for a ship according to an embodiment of the present invention will be described with reference to FIG. 1 .

A liquid fuel venting system for a ship according to an embodiment of the present invention is characterized in that it includes a device for a gasification process of a knockout drum, and a ship using a ME-LGIP engine using LPG as fuel, for example, An example applied to an LPG carrier will be described.

The liquid fuel venting system of the ship according to this embodiment, the service tank 100 for storing the LPG; LPG fuel engine 600 using LPG as fuel; The LPG fuel supply unit 200 for supplying the LPG stored in the service tank 100 to the engine 600 by adjusting the pressure and temperature conditions required by the engine 600 to be satisfied; and a fuel valve train 300 including a plurality of service valves for controlling the supply of LPG fuel supplied from the LPG fuel supply unit 200 to the engine 600 .

According to this embodiment, a large-capacity LPG storage tank (not shown) than the service tank 100 may be further provided. By supplying only the amount of LPG fuel required per day from the LPG storage tank to the service tank 100, the LPG fuel stored in the service tank 100 can be supplied to the LPG fuel engine 600 through the LPG fuel supply unit 200 for one day. have. That is, the service tank 100 may store LPG as much as the amount of fuel consumed by the LPG fuel engine 300 per day.

In addition, the service tank 100 may be a pressure vessel, and LPG at room temperature pressurized to about 18 bar may be stored in a liquid state.

In addition, the service tank 100 may be provided with a safety valve 101 in order to prevent the pressure of the service tank 100 from rising due to natural vaporization of LPG due to temperature rise, such as heat intrusion from the outside. When the pressure of the service tank 100 exceeds 18 bar, the safety valve 101 is opened to vent a gas such as nitrogen or boil-off gas from the service tank 100 .

The LPG stored in the service tank 100 is pressurized by the low pressure pump 110 and transferred to the LPG fuel supply unit 200 along the fuel supply line LL.

A first branch line branched from the fuel supply line LL between the low pressure pump 110 and the LPG fuel supply unit 200 and connected to the service tank 100 is further provided, and as necessary by the low pressure pump 110 Some of the pressurized LPG may be returned to the service tank 100 .

The LPG fuel supply unit 200 of this embodiment includes a high-pressure pump 210 for compressing the LPG pressurized and transported by the low-pressure pump 110 to the pressure required by the LPG fuel engine 600 ; a temperature controller 220 for heating or cooling the LPG compressed by the high-pressure pump 210 to a temperature required by the LPG fuel engine 300; and a filter 230 for protecting the engine 600 by filtering out foreign substances mixed in the LPG transferred from the temperature controller 220 to the LPG fuel engine 600 .

The pressure of the LPG fuel required by the LPG fuel engine 600 may be about 52 bar, for example, about 48 bar to 52 bar in the case of the ME-LGIP engine, and the temperature may be about 25°C to 55°C.

That is, the high-pressure pump 210 of the present embodiment, the pressure of the LPG fuel required by the LPG fuel engine 600, that is, about 40 bar to 70 bar, or about 45 bar to 55 bar, or about 50 bar to 53 bar LPG can be compressed with

The LPG compressed by the high-pressure pump 210 is transferred to the temperature controller 220 along the fuel supply line LL.

A second branch line branched from the fuel supply line LL between the high-pressure pump 210 and the temperature controller 220 and connected to the service tank 100 is further provided, and if necessary, by the high-pressure pump 210 Some of the pressurized LPG may be returned to the service tank 100 .

The minimum temperature of the LPG fuel required by the LPG fuel engine 600 of this embodiment may be about 20 °C to 30 °C.

The temperature controller 220 of this embodiment heats or cools the LPG to about 45° C. or less, or about 25° C. to 45° C., which is the temperature of the LPG fuel required by the LPG fuel engine 600 .

According to this embodiment, LPG compressed to about 50 bar to 53 bar by the high-pressure pump 210 is adjusted to about 25° C. to 45° C. in the temperature controller 220, and foreign substances are filtered by the filter 230. It is supplied to the LPG fuel engine 600 in a liquid state along the post fuel supply line LL.

LPG fuel remaining after being consumed in the LPG fuel engine 600 may be recovered to the service tank 100 along the fuel recovery line RL. The LPG may be in a liquid state discharged from the LPG fuel engine 600 to the fuel recovery line RL, and may be vaporized while being transferred to the service tank 100 side along the fuel recovery line RL. Accordingly, the LPG fuel recovered to the service tank 100 may be in a liquid, gas or gas-liquid mixed state.

Part of the fuel supply line LL and the fuel recovery line RL, in particular, a portion of the fuel supply line LL extending from the connection part with the LPG fuel engine 600 to the LPG fuel supply part 200 side, and the LPG fuel A portion of the fuel recovery line RL extending from the connection part with the engine 600 to the service tank 100 side may be located in a safety area of the engine room where the LPG fuel engine 600 is installed. .

Accordingly, a section in which the fuel supply line LL and the fuel recovery line RL are located in the safety zone, respectively, should be configured as a double pipe, and the section is indicated by a double pipe part 410 in FIG. 1 .

The double pipe part 410 is composed of an inner pipe through which LPG flows and an outer pipe that surrounds the inner pipe at a distance from the inner pipe. It is a structure to prevent unexpected discharge to the outside of the pipe.

The space between the inner pipe and the outer pipe of the double pipe part 410 is filled with air, and according to the official safety regulations of the ship, it is stipulated that the air change of the double pipe part 410 is performed 30 times per hour, and have. By performing the air replacement in this way, it is possible to ensure that LPG that may leak from the inner pipe is always safely discharged overboard.

In order to replace the air, the double pipe part 410 includes an air supply line (not shown) through which the air supplied to the double pipe part 410 flows; and an air venting line (AL) through which air discharged from the double pipe part 410 flows; is connected.

In addition, the air venting line (AL), the air venting valve 420 for controlling the flow of air by the opening and closing control; and an air exhaust fan 430 for venting the fluid transferred through the air venting line AL to the outside.

The liquid fuel venting system of the ship according to this embodiment is a knockout drum (710, 810) for recovering the LPG fuel in the liquid state vented from the LPG fuel supply unit 200, the fuel supply line (LL) and the fuel recovery line (RL). ); further includes.

During operation of the LPG fuel engine 600 , the liquid freeing of the LPG fuel from the LPG fuel engine 600 , or a sudden decrease in pressure due to a sudden load change, etc., causes a supply stop command to be input, or an emergency situation For example, the operation of the LPG fuel engine 600 is stopped and the engine is shut down or an unexpected emergency situation such as a trip may occur.

In addition, when the LPG fuel engine 600 is a dual fuel engine that can be operated in a fuel oil supply mode using fuel oil as a fuel and an LPG supply mode using LPG as a fuel, the fuel of the LPG fuel engine 600 is When switching from LPG fuel to fuel oil, that is, when the engine 600 is switched to the fuel oil supply mode, and the LPG fuel supply mode of the engine 600 must be stopped.

At this time, in order to restart the LPG fuel engine 600 or safely switch the mode, the LPG fuel remaining in the LPG fuel engine 600 or the LPG fuel remaining in the fuel supply line LL and the fuel recovery line RL must be must be removed, and nitrogen purging must be performed.

The knockout drums 710 and 810 according to the present embodiment include a first drum 710 for recovering LPG vented from the LPG fuel supply unit 200; and a second drum 810 for recovering LPG vented from the fuel supply line LL and/or the fuel recovery line RL through the fuel valve train 300 .

In addition, the liquid fuel venting system of the ship according to this embodiment connects the LPG fuel supply unit 200 and the first drum 710 , and the LPG vented from the LPG fuel supply unit 200 is transferred to the first drum 710 . a first drum line (DL1) to be made; It is branched from the fuel supply line LL between the LPG fuel supply unit 200 and the LPG fuel engine 600 and is connected to the second drum 810 and is vented from the fuel supply line LL downstream of the LPG fuel supply unit 200. a second drum line (DL2) through which LPG is transferred to the second drum (810); The LPG branched from the fuel recovery line RL between the LPG fuel engine 600 and the service tank 100 and connected to the second drum 200 is vented from the fuel recovery line RL to the second drum 810 . a third drum line (DL3) to be transferred; and a fourth drum line DL4.

The fuel valve train 300 of this embodiment is a venting valve 240 for venting LPG gas or liquid LPG in the pipe between the service tank 100 and the LPG fuel engine 600 into the knockout drums 710 and 810 . , 330); and double block and bleed valves (310, 320) for blocking the flow of LPG when the supply of LPG is stopped and venting the LPG in the blocked section with knockout drums (710, 810) to relieve pressure; includes

The venting valves 240 and 330 of the present embodiment are provided in the first drum line DL1 and a first venting valve ( 240); and a second venting valve 330 provided in the third drum line DL3 and venting LPG from the fuel recovery line RL to the second drum 810 by opening/closing control.

The stop valves 310 and 320 of this embodiment are configured as a set of a double shut-off valve and an outlet valve, that is, three valves.

Referring to FIG. 1 , the stop valves 310 and 320 of this embodiment include a first stop valve 310 for controlling the flow of LPG vented from the fuel supply line LL to the second drum 810; and a second stop valve 320 for controlling the flow of LPG vented from the fuel recovery line RL to the second drum 810 .

The double shut-off valve of the first stop valve 310 includes a first shut-off valve (reference numeral not assigned) provided in the fuel supply line LL upstream of the branch point of the second drum line DL2, and the second drum line and a second shut-off valve (reference numeral not assigned) provided in the fuel supply line LL downstream of the branch point of DL2. In addition, a first outlet valve (reference numeral not assigned) which is an outlet valve of the first stop valve 310 is provided in the second drum line DL2.

The double shut-off valve of the second shut-off valve 320 includes a third shut-off valve (reference numeral not assigned) provided in the fuel recovery line RL upstream of the branch point of the fourth drum line DL4, and the fourth drum line and a fourth shut-off valve (reference numeral not assigned) provided in the fuel recovery line RL downstream of the branch point of DL4. In addition, a second outlet valve (reference numeral not assigned) which is an outlet valve of the second stop valve 320 is provided in the fourth drum line DL4.

For example, when LPG is supplied as the fuel of the LPG fuel engine 600 , the first shut-off valve and the second shut-off valve are opened so that the LPG is transferred from the LPG fuel supply unit 200 to the LPG fuel engine 600 . On the other hand, when the fuel supply of LPG is cut off and fuel is switched to fuel oil, the first shutoff valve and the second shutoff valve are closed and the first outlet valve is opened, so that the LPG remaining between the first shutoff valve and the second shutoff valve By venting into the second drum 810 through the second drum line DL2, the pressure between the first shutoff valve and the second shutoff valve is relieved to prevent the risk of fuel explosion.

In this procedure, when the fuel valve train 300 supplies LPG fuel from the LPG fuel supply unit 200 to the engine 600, when the fuel of the engine 600 is converted to fuel oil, that is, the engine 600 is converted to fuel oil. When switching to the supply mode, it is always operated when the LPG fuel supply mode of the engine 600 is stopped.

The first drum 710 of this embodiment includes a first level sensor 730 for detecting the liquid level of the LPG in the first drum 710; and a first heating jacket 720 for heating the liquid LPG in the first drum 710 to promote vaporization so that the LPG water level is less than an appropriate hold up volume.

In addition, the second drum 810 of this embodiment has a second level sensor 830 for detecting the liquid level of the LPG in the second drum 810; and a second heating jacket 820 for heating the liquid LPG in the second drum 810 to promote vaporization so that the LPG water level is less than an appropriate retention amount.

On the other hand, the marine fuel supply system, the coolant cooler 510 for supplying coolant to the LPG fuel engine 600 in order to cool the jacket of the marine engine; A coolant circulation line (CL) that provides a path for the low-temperature coolant cooled by the coolant cooler 510 to be supplied to the LPG fuel engine 600, and the high-temperature coolant heated while cooling the jacket to circulate back to the coolant cooler 510 ); and a circulation pump 520 that pressurizes the high-temperature coolant discharged from the LPG fuel engine 600 and circulates it to the coolant cooler 510;

According to the present embodiment, the second heating line (CL2) branched from the coolant circulation line (CL) to supply the high-temperature coolant discharged from the LPG fuel engine 600 as a heat source of the first heating jacket 720; and a first heating line CL1 branched from the coolant circulation line CL and configured to supply high-temperature coolant discharged from the LPG fuel engine 600 as a heat source of the second heating jacket 820 .

That is, the liquid LPG in the first drum 710 and the second drum 720 is vaporized by the thermal energy of the high-temperature coolant transferred through the second heating line CL2 and the first heating line CL1 .

The low-temperature coolant cooled while vaporizing the liquid LPG in the first drum 710 is recovered to the coolant cooler 510 through the second heating line CL2, while vaporizing the liquid LPG in the second drum 810 The cooled low-temperature cooling water is recovered to the cooling water cooler 510 through the first heating line CL1.

In addition, according to the present embodiment, the low-temperature coolant transferred through the first heating line CL1 and the second heating line CL2 bypasses the coolant cooler 510 and is supplied to the jacket of the LPG fuel engine 600 . Bypass line (CRL) to be connected; and a temperature control valve 530 for controlling the flow path so that the low-temperature coolant transferred through the first heating line CL1 and the second heating line CL2 is supplied to the coolant cooler 510 or the LPG fuel engine 600 ; may further include.

* The temperature of the high-temperature coolant discharged from the LPG fuel engine 600 is constant at about 80 to 85° C., but the temperature range of the coolant supplied from the coolant cooler 510 to the LPG fuel engine 600 is wide. According to the present embodiment, by controlling the temperature control valve 530 , it is possible to control the temperature of the low-temperature coolant supplied to the LPG fuel engine 600 according to the conditions required by the LPG fuel engine 600 .

In this embodiment, the low temperature coolant temperature supplied to the LPG fuel engine 600 may be about 70 to 80 ℃.

The liquid fuel venting system of the ship according to this embodiment, the first ejector 750 for discharging the gas (gas) from the first drum 710 by making the first drum 710 in a vacuum state; a first venting line (VL1) connecting the first drum 710 and the first ejector 750 and providing a path through which gas is discharged from the first drum 710 to the overboard; a second ejector 850 for discharging gas from the second drum 810 by making the second drum 810 into a vacuum state; and a second venting line VL2 connecting the second drum 810 and the second ejector 850 and providing a path through which gas is discharged from the second drum 810 to the overboard.

On the other hand, in the ship, when the LPG fuel supply is stopped, such as when the LPG fuel engine 600 is switched to the fuel oil mode, nitrogen ( N ₂ ) A nitrogen supply device (not shown) for producing and supplying; is provided.

According to this embodiment, a first nitrogen supply line (NL1) connecting the nitrogen supply device and the first ejector 750 so that nitrogen gas is supplied as a working fluid of the first ejector 750 from the nitrogen supply device provided in the ship. ; and a second nitrogen supply line NL2 connecting the nitrogen supply device and the second ejector 850 so that nitrogen gas is supplied from the nitrogen supply device as a working fluid of the second ejector 850 .

The first ejector 750 and the second ejector 850 discharge gaseous LPG from the first drum 710 and the second drum 810 by using the nitrogen gas supplied from the nitrogen supply device as a working fluid. However, the vacuum degree of the first drum 710 and the second drum 810 and the performance of the ejector increase according to the pressure and flow rate of nitrogen gas supplied as the working fluid.

In this embodiment, the pressure of nitrogen gas supplied from the nitrogen supply device to the first ejector 750 and the second ejector 850 may be about 5 bar to 10 bar or about 8 bar.

A first ejector valve 760 for controlling the flow of nitrogen gas supplied from the nitrogen supply device to the first ejector 750 is provided in the first nitrogen supply line NL1, and the second nitrogen supply line NL2 is provided. A second ejector valve 860 for controlling the flow of nitrogen gas supplied from the nitrogen supply device to the second ejector 850; is provided.

In addition, in this embodiment, the gas in the first drum 710 and the second drum 810 may be vented by the first ejector 750 and the second ejector 850 as well as the air exhaust fan 430 . ) may be vented by

The liquid fuel venting system of the ship according to this embodiment includes: a first selection line (FL1) branched from the first venting line (VL1) and connected to the air venting line (AL); and a second selection line FL2 branched from the second venting line VL2 and connected to the air venting line AL.

The first selection line FL1 is branched from the first ejector 750 upstream of the first venting line VL1, and is an air venting line AL between the air venting valve 420 and the air exhaust fan 430. connected In addition, at the point where the first selection line FL1 is branched from the first venting line VL1 , the gas from the first drum 710 to any one or more of the first ejector 750 and the air exhaust fan 430 . A first selection valve 740 is provided as a three-way valve for controlling the path to be vented by the

The second selection line FL2 is branched from the upstream of the second ejector 850 of the second venting line VL2 to the air venting line AL between the air venting valve 420 and the air exhaust fan 430 . connected In addition, at the point where the second selection line FL2 is branched from the second venting line VL2 , the gas from the second drum 810 to any one or more of the second ejector 850 and the air exhaust fan 430 . As a three-way valve for controlling the path to be vented by the second selection valve 840; is provided.

That is, in this embodiment, the gas vented from the first drum 710 is controlled by the flow path of the first selection valve 740 through any one or more of the first ejector 750 and the air exhaust fan 430 . Can be vented overboard.

In addition, the gas vented from the second drum 810 is to be vented outboard through any one or more of the second ejector 850 and the air exhaust fan 430 by the flow control of the second selection valve 840 . can

The control unit, not shown, is, according to the water level measurement value of the first level sensor 730, when the water level of the first drum 710 exceeds an appropriate retention amount, the jacket cooling water from the LPG fuel engine 600 is supplied to the first heating jacket ( 720), and opening and closing of the first selection valve 740 so that LPG vaporized in the first drum 730 is vented outboard by any one or more of the first ejector 750 and the air exhaust fan 430 By controlling the direction, the path of the gas discharged from the first drum 730 is controlled. In addition, the control unit may control whether the first ejector 750 and the air exhaust fan 430 are operated according to the control direction of the first selection valve 740 , and may control the opening and closing of the first ejector valve 760 . can

In addition, when the water level of the second drum 810 exceeds the appropriate retention amount according to the water level measurement value of the second level sensor 830 , the control unit receives the jacket cooling water from the LPG fuel engine 600 in the second heating jacket 820 . ), and the opening and closing direction of the second selection valve 840 so that the LPG vaporized in the second drum 830 is vented outboard by any one or more of the second ejector 850 and the air exhaust fan 430 . to control the path of the gas discharged from the second drum 830. In addition, the control unit may control whether the second ejector 850 and the air exhaust fan 430 are operated according to the control direction of the second selection valve 840 , and may control the opening and closing of the second ejector valve 860 . can

In the case of venting the gas from the first drum 710 and/or the second drum 810 to the outboard using the air exhaust fan 430, the air venting valve 420 is closed to can block air ventilation. When the LPG fuel engine 600 is not in the LPG fuel supply mode, since air circulation in the double pipe is unnecessary, the gas from the first drum 710 and the second drum 720 using the air exhaust fan 430 . Venting is possible.

A method of operating a liquid fuel venting system for a ship according to an embodiment of the present invention is as follows.

When LPG is discharged from the knockout drums 710 and 810 to the atmosphere, the liquid LPG starts to vaporize. According to this embodiment, the heating jackets 720 and 820 are used to promote vaporization of LPG. The heat source supplied to the heating jackets 720 and 820 to vaporize the liquid LPG in the knockout drums 710 and 810 cools the heat of the jacket of the LPG fuel engine 600 and utilizes the discharged high-temperature coolant.

Since the high-temperature coolant discharged from the LPG fuel engine 600 must be cooled and circulated back to the jacket of the engine, a cooling process is essential, and the high-temperature coolant can be cooled by the cold heat of LPG and circulated to the engine. As described above, when the jacket coolant of the engine is used as a heat source, energy required for vaporization of LPG and cooling of the coolant can be reduced, while the load of the LPG fuel engine 600 is high during the operation of the ship, so a larger amount of heat source It has the advantage of being able to obtain

In addition, if the air exhaust fan 430 for air circulation 30 times per minute of the double pipe part 410 is utilized, the LPG rapidly vaporized by the heating jackets 720 and 820 can be smoothly vented outboard, and the LPG is evaporated. There is also an effect that can promote evaporation by lowering the pressure.

The air exhaust fan 430 is always operated in the LPG fuel supply mode of the LPG fuel engine 600 to successfully circulate the air of the double pipe part 410, but when the knockout drums 710 and 810 are operated, That is, when the supply of LPG fuel is stopped, since air circulation of the double pipe part 410 is unnecessary, the air venting valve 420 may be closed and the gas may be vented from the knockout drums 710 and 810 .

In addition, in the case of venting the vaporized LPG by operating the ejectors 750 and 850, a vacuum is formed inside the knockout drums 710 and 810 to lower the evaporation pressure, thereby maximizing the liquid LPG in the knockout drums 710 and 810. It can evaporate quickly. In addition, the ejectors 750 and 850 can prevent a risk by using nitrogen gas of about 8 bar, ie, an inert gas, as a working fluid from a nitrogen supply device that is essential in the ship.

In addition, by controlling the selection valves (740. 840), it is possible to selectively vent the gas from the knockout drums (710, 810) by utilizing any one or more of the air exhaust fan (430) and the ejectors (750. 850).

In this embodiment, the air exhaust fan 430, the ejectors 750, 850, the selection valves 740, 840, and the ejector valves 760, 860 are organically controlled with each other by the control unit, and the air exhaust fan 430 and The ejectors 750 and 850 are selectively configured to be movable individually or simultaneously.

That is, the priority of the operation of the air exhaust fan 430 and the ejectors 750 and 850 is selectable by the operator, and it is also possible to utilize both configurations at the same time. In order to utilize both configurations at the same time, the opening degree of the selection valves 740 and 840 may be configured to be adjustable in both directions.

However, when the air exhaust fan 430 is used to vent the gas in the knockout drums 710 and 810, the LPG fuel engine 600 is not operated in the LPG fuel supply mode or the LPG fuel supply mode to stop, the air venting valve 420 is closed, and the air circulation function of the double pipe part 410 must be stopped.

As described above, according to the present invention, the LPG fuel engine 600 can be quickly restarted by quickly vaporizing the liquid LPG in the knockout drums 710 and 810 to lower the water level, and thus the LPG fuel supply system And it is possible to safely, efficiently and stably operate the LPG fuel engine 600 .

As described above, the embodiments according to the present invention have been reviewed, and the fact that the present invention can be embodied in other specific forms without departing from the spirit or scope of the present invention in addition to the above-described embodiments is recognized by those with ordinary skill in the art. It is self-evident to Therefore, the above-described embodiments are to be regarded as illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description, but may be modified within the scope of the appended claims and their equivalents.

100: service tank 200: LPG fuel supply unit
101: safety valve 210: high pressure pump
110: low pressure pump 220: temperature controller 230: filter
300: fuel valve train
310: first stop valve 320: second stop valve
240: first venting valve 330: second venting valve
410: double pipe part 510: coolant cooler
420: air venting valve 520: circulation pump
430: air exhaust fan 530: temperature control valve
600: LPG fuel engine
710, 810: knockout drum 720, 820: heating jacket
730, 830: level sensor 740, 840: selection valve
750, 850: ejector 760, 860: ejector valve

Claims (4)

service tanks for storing liquid fuel;
an engine receiving the liquid fuel stored in the service tank in a liquid state and using it as fuel;
a fuel supply unit for controlling the liquid fuel discharged from the service tank to the pressure and temperature required by the engine;
a knockout drum for recovering liquid fuel in a liquid or gas-liquid mixed state from the fuel supply unit and the engine; and
In order to restart the engine when the operation of the engine is stopped, accelerating means for accelerating vaporization and venting of the liquid fuel stored in the knockout drum so as to reach an appropriate water level at a faster speed than when the knockout drum is in a normal state; , liquid fuel venting systems for ships. The method according to claim 1,
The facilitation means,
A liquid fuel venting system for a ship, including; a heating jacket for vaporizing the liquid fuel stored in the knockout drum by receiving cooling water whose temperature is increased while cooling the jacket of the engine. The method according to claim 1,
a fuel supply line connecting the fuel supply unit and the engine, providing a flow path through which liquid fuel is supplied from the fuel supply unit to the engine, and formed of a double pipe; and
Further comprising; an air exhaust fan for discharging air from the double pipe at a certain number of times per hour in order to circulate the air of the double pipe;
The facilitation means,
A selection line for connecting the knockout drum and the air exhaust fan to lower the vaporization pressure of the liquid fuel in the knockout drum by the air exhaust fan to promote gas discharge from the knockout drum; Containing, Liquid fuel venting system of a ship. The method according to claim 1,
In order to restart the engine, an inert gas supply device for supplying an inert gas for purging to the fuel supply unit; further comprising,
The facilitation means,
A liquid fuel venting system for ships, including; an ejector that receives an inert gas from the inert gas supply device and uses it as a working fluid, and forms a vacuum level in the knockout drum to promote gas discharge from the knockout drum.

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