KR20220012468A - Fuel gas supply system of ship - Google Patents

Abstract

A fuel gas supply system for a ship is disclosed. The fuel gas supply system for a ship according to the present invention comprises: a main engine which can be driven using fuel gas and which is provided as an engine for propulsion of a ship; a fuel tank in which the fuel gas is stored; a fuel supply unit which supplies the fuel gas stored in the fuel tank according to the conditions required by the main engine; a gas valve train (GVT) which finally controls the pressure and flow rate of the compressed fuel gas in the fuel supply unit and which supplies the compressed fuel gas to the main engine; and a high-pressure fuel gas supply line which is connected from the GVT to the main engine and which is provided with a double pipe, wherein the high-pressure fuel gas supply line is characterized in that an outer tube is formed in a vacuum so that the outer tube can be quickly replaced with nitrogen gas when a leakage occurs in an inner tube. An objective of the present invention is to provide the fuel gas supply system for a ship that can be suitably applied to an LFS.

Description

Fuel gas supply system for ships {FUEL GAS SUPPLY SYSTEM OF SHIP}

The present invention relates to a fuel gas supply system for a ship, and more particularly, to a fuel gas supply system for a ship that can be suitably applied to an LFS operated with a separate fuel tank.

In general, combustion devices such as engines installed in various ships used oils such as MDO (Marine Diesel Oil) and HFO (Heavy Fuel Oil) as fuel. However, such fuel oil has been the main culprit in causing environmental pollution due to greenhouse gases and various harmful substances generated during combustion. In addition, when oil prices rise due to factors such as depletion of fossil fuels or international political instability, problems in ship operation such as fuel costs soar are also generated.

Recently, as air pollution regulations have been gradually tightened, clean fuels such as liquefied natural gas (LNG) with low sulfur oxides (SOx) and nitrogen oxides (NOx) are becoming an energy source to replace fuel oil. A DF engine (Dual Fuel Engine) that can use both fuel oil and fuel gas has been developed and is being used in ships.

Meanwhile, in LNGC (LNG Carrier), which transports large quantities of LNG, the technology of using LNG stored in a storage tank as fuel for an engine has already been applied. In particular, application to very large crude-oil carriers (VLCCs) or container ships is being considered.

Unlike LNGC, which uses LNG as a fuel while carrying it as cargo, a separate LNG fuel tank must be installed in order to use LNG as a fuel in general ships. A ship operated with a separate LNG fuel tank in this way is called an LFS (LNG Fueled Ship).

However, in the case of LFS, unlike the existing LNGC, the fuel supply system is complicated and requires a technology to solve this problem.

Accordingly, an object of the present invention is to provide a fuel gas supply system for a ship that can be suitably applied to the LFS, and in particular, it is possible to secure stability while satisfying the classification requirements and to configure a system that can reduce power consumption. do.

According to one aspect of the present invention for achieving the above object, it is possible to drive using fuel gas, the main engine is provided as a propulsion engine of a ship; a fuel tank in which the fuel gas is stored; a fuel supply unit supplying the fuel gas stored in the fuel tank according to the conditions required by the main engine; a gas valve train (GVT) that finally controls the pressure and flow rate of the fuel gas compressed in the fuel supply unit and supplies it to the main engine; and a high-pressure fuel gas supply line connected from the GVT to the main engine and provided with a double pipe, wherein the high-pressure fuel gas supply line is an external pipe to quickly replace the external pipe with nitrogen gas when a leak occurs in the internal pipe. A fuel gas supply system for a ship can be provided, characterized in that the tube is formed in a vacuum.

A fuel gas supply system for a ship according to the present invention includes: an ejector that sucks in the gas present in the outer tube to form a vacuum; and a nitrogen supply unit for supplying compressed nitrogen gas as a driving fluid of the ejector.

In addition, the fuel gas supply system of the ship according to the present invention, a vacuum suction line for sucking the gas inside the outer tube toward the ejector; a vacuum injection line for discharging the gas sucked into the ejector through the vacuum suction line to an outboard; and a nitrogen supply line for supplying the compressed nitrogen gas from the nitrogen supply unit to the ejector.

In addition, the fuel gas supply system of the ship according to the present invention, a three-way valve installed on the vacuum injection line; and a nitrogen filling line branched from the vacuum injection line at the point where the three-way valve is installed and connected to the outer tube, and when the inner tube leaks, the three-way valve is directed toward the nitrogen filling line. By conversion, the nitrogen gas supplied from the nitrogen supply unit to the ejector may be filled into the outer tube.

The vacuum suction line and the nitrogen filling line are connected to the ends and ends of the high-pressure fuel gas supply line, respectively, so that the vacuum suction line and the nitrogen filling line are formed as far apart as possible from the connection point to ensure smooth circulation of the outer tube can induce

The nitrogen supply unit may supply nitrogen gas as a purging gas for purging the main engine.

The fuel gas supply system of the ship according to the present invention may further include a purging line for supplying the nitrogen gas from the nitrogen supply unit for the purpose of purging the main engine, and the nitrogen gas supplied to the purging line is the main After being supplied to the engine and purging the inside of the main engine and the high-pressure fuel gas supply line, it may be discharged to the outside air through the GVT.

The fuel supply unit and the GVT may be disposed in a cargo compressor room (Cargo Compressor Room), and the cargo compressor room may be located in a cargo area of the vessel.

The cargo compressor room may be classified as a gas hazardous zone in which ventilation is performed periodically.

The cargo area may be located in front of the engine room of the stern in which the main engine is disposed.

The fuel gas supply system for a ship according to the present invention may further include a cofferdam that is partitioned and provided on an interface between the engine room and the cargo area, and the high-pressure fuel gas supply line passes through the inside of the cofferdam and the It may be connected to the main engine through the front bulkhead of the engine room.

The cofferdam may be periodically ventilated with respect to the internal space.

A fuel gas supply system for a ship according to the present invention includes: an exhaust fan installed on a first vent line for discharging air inside the cofferdam; and an eductor installed on a second vent line for discharging the air inside the cofferdam, wherein the ventilation inside the cofferdam selectively operates the exhaust fan and the eductor individually or This can be done by running them simultaneously.

When the eductor is individually operated, the eductor may be operated by receiving the pressure of the compressed nitrogen gas supplied from the nitrogen supply unit.

When ventilation of the inside of the cofferdam is performed using only the eductor, it may be possible to delete the exhaust fan.

When the exhaust fan and the eductor are simultaneously operated, the eductor may be operated by receiving at least one of a pressure formed by the exhaust fan and a pressure of compressed nitrogen gas supplied from the nitrogen supply unit.

The fuel gas supply system for a ship according to the present invention uses a pressurized fuel tank, and by configuring the line to which fuel gas is supplied to the engine with a vacuum double tube, the stability of the system is significantly improved while satisfying the classification requirements. It works.

In addition, according to the present invention, when a leak occurs on the fuel supply line and the fuel gas supply line composed of a double pipe, it is possible to quickly discharge the leaked gas, which is an operational advantage in that the engine can be quickly restarted in an emergency. Also, it is possible to discharge the leaked gas to a desired area using pressure, which has an advantage in piping design.

In addition, according to the present invention, it is possible to reduce the power consumption of the exhaust fan provided in the gas valve unit room, and in some cases, it is also possible to delete the exhaust fan, there is an effect of reducing OPEX and CAPEX.

1 is a view schematically showing a fuel gas supply system for a ship according to the present invention.

In order to fully understand the present invention, 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.

In this specification, 'fuel gas' used as a fuel for a ship includes LNG, LPG (Liquefied Petroleum Gas), LEG (Liquefied Ethane Gas), Liquefied Ethylene Gas, Liquefied Propylene Gas, etc. Likewise, it can be stored by liquefying it at a low temperature and can include all kinds of liquefied gas that can be supplied as fuel of the engine in a vaporized state. However, hereinafter, for convenience of explanation, LNG, which is a representative liquefied gas, will be described as an example.

In addition, in this specification, the term 'ship' may be interpreted as a concept including all types of ships that can use fuel gas as fuel for an engine. Typically, ships with self-propelled capabilities such as LFS, which are propelled using LNG as fuel, as well as offshore structures floating in the sea such as LNG FPSO (Floating Production Storage Offloading) and LNG FSRU (Floating Storage Regasification Unit) will be included. can

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in each figure indicate like elements.

1 is a view schematically showing a fuel gas supply system for a ship according to the present invention.

Referring to FIG. 1 , the fuel gas supply system according to the present invention includes a gas engine 110 and a main engine 120 using LNG as a fuel; a fuel tank 200 for storing LNG supplied as a fuel of the engines 110 and 120; a fuel supply unit 300 for supplying LNG stored in the fuel tank 200 according to the conditions required by the engines 110 and 120; A nitrogen supply unit for supplying nitrogen gas for the purpose of controlling the internal pressure by pressurizing the fuel tank 200 and for purging the line through which LNG is supplied to the inside of the engines 110 and 120 and the engines 110 and 120 (400).

The engines 110 and 120 may be engines that can be driven by using LNG as a fuel. Therefore, it includes a DF engine (Dual Fuel Engine) that can use both heavy oil and natural gas as fuel, for example, a propulsion engine such as an ME-GI engine or an X-DF (eXtreme Dual Fuel) engine, or a DFDG (Dual Fuel Diesel Generator) engine. It can be applied to all general generator engines such as

In a preferred embodiment presented in the present invention, the gas engine 110 is a low-pressure gas injection engine driven by receiving fuel gas of about 10 bar or less, and may be a generator engine for generating necessary power in the ship, and the main engine 120 is As a high-pressure gas injection engine driven by receiving fuel gas of approximately 200 to 400 bar, it may be an engine for propulsion of a ship, for example, it may be provided as an ME-GI engine.

The engines 110 and 120 are disposed in an engine room (E/R) provided at the stern. The engine room (E/R) is classified as a gas safe zone, and it is an area where safety from the gas hazardous zone must be secured. For example, direct access from the gas hazardous area to the gas safe area is prohibited (if necessary, an air lock is installed), and the fuel supply pipe passing through the gas safe area must be completely enclosed by a double pipe or duct.

The fuel tank 200 may be provided as a pressurized (pressure type) tank that stores LNG supplied as fuel of the engine 100 in a liquefied state and maintains a predetermined pressure or more at all times.

The fuel tank 200 may include a pressurizing unit 210 that is pressurized by nitrogen gas supplied from the nitrogen supply unit 400 through the pressure maintaining line ML to maintain the internal pressure.

The pressurizing unit 210 constitutes a part of the fuel tank 200 , and transmits pressure energy by nitrogen gas supplied from the nitrogen supply unit 400 to the fuel tank 200 to control the pressure of the fuel tank 200 . can

For example, the fuel tank 200 and the pressurizing unit 210 may be manufactured as an integral tank, and the space may be partitioned by a diaphragm capable of contracting and expanding or reciprocating by a piston, and thus the pressurizing unit The pressure of the fuel tank 200 may be controlled by adjusting the amount of nitrogen gas supplied to the inner space of the 210 .

A tank pressure sensor 201 for measuring the internal pressure of the tank may be installed in the fuel tank 200 . When the value measured by the tank pressure sensor 201 falls below a predetermined value, nitrogen gas is supplied from the nitrogen supply unit 400 to the pressurization unit 210 so that the fuel tank 200 can maintain a predetermined pressure or more, It is possible to prevent the LNG inside the fuel tank 200 from being vaporized.

The fuel tank 200 may be disposed on the stern side main deck to be close to the engines 110 and 120, but the present invention is not limited thereto. In recent container ships, there is a trend of arranging accommodation in the center of the vessel to secure visibility. When the present invention is applied to such a container ship, the fuel tank 200 is installed in the lower space of the accommodation where it is difficult to load the container. can also be placed. In this case, the space between the living quarters and the fuel tank 200 may be separated by a cofferdam or the like.

In addition, the fuel tank 200 of the present invention may be provided as a pressurized tank as an independent type tank that can be mounted, but may be provided as a membrane type tank manufactured using the inner wall of the hull. is of course

The fuel supply unit 300 is configured to supply the LNG stored in the fuel tank 200 according to the conditions required by the engines 110 and 120, and by forcibly vaporizing and compressing the LNG stored in the fuel tank 200, the engine ( 110 and 120 ) or compressed BOG (evaporated gas) generated by natural vaporization of LNG in the fuel tank 200 may be supplied to the engines 110 and 120 .

The fuel supply unit 300 compresses a vaporizer for forcibly vaporizing LNG, LNG vaporized by the vaporizer, or BOG naturally generated in the fuel tank 200 to the pressure required by the engines 110 and 120 . It may include a compressor, a heater, and the like.

On the other hand, since the fuel gas pressure and temperature required by the gas engine 110 driven by receiving the low pressure gas and the main engine 120 driven by receiving the relatively high pressure fuel gas are different from each other, each engine 110 , 120) needs to be supplied in accordance with the fuel gas conditions required. To this end, in order to meet the conditions of the main engine 120 requiring high-pressure fuel gas, the compressor may be configured as a multi-stage compressor, and only a part of the multi-stage compressor is included in the gas engine 110 requiring a relatively low pressure fuel gas. A known method, such as a coarse fuel gas being supplied, may be used.

In addition, since the pressure of the fuel gas required by the gas engine 110 and the main engine 120 is different, the fuel gas supply line ( SL1 and SL2) may be provided, respectively.

At this time, on the fuel gas supply lines SL1 and SL2, the pressure of the fuel gas supplied to the engines 110 and 120 is quickly controlled according to the load of the engines 110 and 120, and the supply of the fuel gas is quickly cut off when necessary. A valve-like device is installed to control the

In the present invention, the control valves installed on the first fuel gas supply line SL1 connected to the gas engine 110 are grouped and referred to as a gas valve unit (GVU) 310, and the main engine ( Control valves installed on the second fuel gas supply line SL2 connected to 120 are grouped and defined as a gas valve train (hereinafter referred to as GVT) 320 .

The fuel supply unit 300 and the GVT 320 may be disposed in a cargo compressor room 10 , and the cargo compressor room 10 may be disposed in a cargo area. Here, the cargo area may refer to an area commonly referred to as a cargo area in a ship, and in this embodiment, a space in which cargo is loaded, which is located in front of the engine room area (E/R Area) to ensure safety. can mean In addition, in the case of LNGC, an upper portion of a cargo tank may be defined as a cargo area, and in this case, the cargo area may mean an area to which LNG gas may be exposed.

In the present invention, the cargo compression room 10 may be arranged by providing a separate space above the main deck on the stern side of the cargo area so as to be close to the engines 110 and 120 . However, the present invention is not limited thereto, and as described above, when the present invention is applied to a container ship, the cargo compressor room 10 together with the fuel tank 200 may be disposed at the lower part of the residence.

Unlike the GVT (320) being disposed in the cargo compressor room (10), the GVU (310) is located in the rear of the engine room (E / R) in the gas valve unit room (GVU Room, hereinafter GVU room) (20) can be placed. This is because, unlike the GVT 320 that handles high-pressure fuel gas, the GVU 310 must be disposed close to the gas engine 110 because it handles fuel gas of a relatively low pressure.

The GVU room 20 is a space classified as a gas hazardous area and should be arranged in an area isolated from the engine room (E/R). In addition, for safety reasons, periodic ventilation should be performed, and in general, dry air is exchanged 30 times per hour to prepare for gas leakage. Therefore, the exhaust fan F2 may be provided in the GVU room 20 to allow ventilation at any time. The exhaust fan F2 should always be operated in the gas mode in which the gas engine 110 uses LNG as a fuel.

In the present invention, the process of supplying fuel gas from the fuel tank 200 to the engines 110 and 120 may be performed as follows. First, LNG stored in the fuel tank 200 is supplied to the fuel supply unit 300 through the fuel supply line FL. The (low pressure) fuel gas supplied from the fuel supply unit 300 to the gas engine 110 is supplied to the gas engine 110 through the first fuel gas supply line SL1, and in this process, the GVU 310 finally Pressure and flow are controlled. The (high pressure) fuel gas supplied from the fuel supply unit 300 to the main engine 120 is a second fuel gas supply line SL2 after the pressure and flow are controlled by the GVT 320 in the cargo compressor room 10 . ) through the main engine 120 is supplied.

Here, the fuel supply line FL may be provided as a double pipe. This is a design to satisfy the classification requirements, and in the case of the fuel supply line (FL), since the fuel tank 200 has pressure, it is composed of a double pipe.

Meanwhile, the line SL1-1 disposed on the Weather Deck and inside the GVU room 20 among the first fuel gas supply line SL1 may be configured as a single pipe. This is because the first fuel gas supply line SL1 handles low-pressure fuel gas of about 10 bar or less, and the GVU room 20 is a gas hazardous area configured to be ventilated at all times.

On the other hand, the line SL1-2 connected from the GVU 310 to the gas engine 110 among the first fuel gas supply line SL1 is disposed in the engine room E/R classified as a gas safety zone, so it is a double pipe. should be provided

In addition, since the second fuel gas supply line SL2 handles high-pressure fuel gas of approximately 200 to 400 bar, from the rear end of the GVT 320 to the main engine 120 must be configured as a double pipe.

In the present invention, the second fuel gas supply line (SL2) may be disposed to pass through the inside of the cofferdam 30 that is partitioned and provided at the interface between the engine room (E/R) room and the cargo area, and the main engine 120 as much as possible. After extending downward to the position of , it may be connected to the main engine 120 through the front bulkhead of the engine room (E/R).

According to the present invention, periodic ventilation (air exchange 30 times per hour) may be performed for the internal space of the cofferdam 30, and for this purpose, the cofferdam 30 may also include an exhaust fan F1. .

At this time, according to the present invention, the inside of the cofferdam 30 may be ventilated by installing a first eductor 610 for a backup of the exhaust fan F1 . That is, the ventilation inside the cofferdam 30 may be performed by the exhaust fan F1 or the first eductor 610, or by operating the exhaust fan F1 and the first eductor 610 together. It can also be configured to ventilate more quickly.

Typically, ventilation using the exhaust fan F1 has a disadvantage in that power consumption is large. In the present invention, the first eductor 610 is installed to replace the role of the exhaust fan F1 or the exhaust fan F1. By assisting the role of , there is an effect of increasing the ventilation efficiency and reducing the power consumption of the exhaust fan F1. In addition, it is possible to quickly respond to an urgent need to perform ventilation.

Specifically, when the first eductor 610 is operated individually, the first eductor 610 receives the compressed nitrogen gas provided from the nitrogen supply unit 400 as a driving fluid and receives the cofferdam ( 30) It is possible to perform internal ventilation.

To this end, a first pressure supply line OL1 for supplying nitrogen gas from the nitrogen supply unit 400 to the first eductor 610 may be connected to the first eductor 610 , and the first pressure supply line OL1 may be connected to the first eductor 610 . ), a first pressure control valve (OV1) for controlling the supply of nitrogen gas may be installed.

When the exhaust fan F1 and the first eductor 610 are operated together, the first eductor 610 is operated by receiving the positive pressure provided by the exhaust fan F1, or at the same time, the above-described nitrogen The nitrogen gas provided from the supply unit 400 may be additionally supplied as a driving fluid.

As shown in FIG. 1 , the first eductor 610 may be installed to be connected to the rear end of the exhaust fan F1 , considering the individual operation of the first eductor 610 and the exhaust fan F1 . Thus, a first vent line VL1 for discharging air through the exhaust fan F1 and a second vent line VL2 for discharging air through the first eductor 610 may be provided, respectively.

In addition, a first non-return valve BV1 may be installed on a line connecting the first eductor 610 and the exhaust fan F1 . The first non-return valve BV1 serves to isolate the first eductor 610 and the exhaust fan F1 when they are individually operated, and exhaust from the first eductor 610 during simultaneous operation. By preventing pressure loss toward the fan F1 , the efficiency of the first eductor 610 may be increased.

As described above, in the present invention, by configuring the fuel supply line FL, a part of the first fuel gas supply line SL1, and the second fuel gas supply line SL2 in a double pipe structure, the LNG gas in the inner pipe Even in case of leakage, safety can be secured double by the outer tube surrounding the inner tube.

In the fuel supply line FL, the line SL1-2 consisting of a double pipe in the first fuel gas supply line SL1, and the second fuel gas supply line SL2, the leakage of the inner pipe can be detected, respectively. A gas sensor GD may be installed.

In addition, the present invention forms the outer tube of the fuel supply line (FL), the first fuel gas supply line (SL1-2) and the second fuel gas supply line (SL2) composed of a double tube in a vacuum state, so that the inner tube It is characterized in that the system is configured to quickly replace the external pipe with nitrogen gas in case of leakage of LNG gas.

A fuel gas supply system for a ship according to the present invention is a fuel supply line (FL) composed of a double pipe, the first fuel gas supply line (SL1-2) and the outer tube of the second fuel gas supply line (SL2) in a vacuum state It may further include an ejector (Ejector) 500 is installed to form a.

The ejector 500 sucks the gas between the outer and inner tubes of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 to form a vacuum. .

Specifically, the outer tube of the fuel supply line FL is connected to the ejector 500 through the first vacuum suction line IL1, and the first fuel gas supply line SL1-2 is connected to the second vacuum suction line IL2. ) through the ejector 500, the second fuel gas supply line SL2 may be connected to the ejector through the third vacuum suction line IL3. At this time, the first vacuum suction line IL1 , the second vacuum suction line IL2 , and the third vacuum suction line IL3 may be integrated into one line and connected to the suction port of the ejector 500 .

The air existing in the outer tube of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 is sucked into the ejector 500 to close the vacuum injection line EL. It is discharged to the outside (outboard) through the fuel supply line FL, the first fuel gas supply line SL1-2, and the external pipes of the second fuel gas supply line SL2 may be formed in a vacuum state. .

In this case, nitrogen gas supplied from the nitrogen supply unit 400 may be used as a driving fluid of the ejector 500 . The nitrogen supply unit 400 supplies the compressed nitrogen gas as the driving fluid of the ejector 500 through the nitrogen supply line NL, the fuel supply line FL, the first fuel gas supply line SL1-2, and the second 2 Provides a pressure to suck in the air existing in the outer pipe of the fuel gas supply line (SL2).

A pressure sensor PT may be installed in the outer pipe of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 for the purpose of measuring the degree of vacuum, respectively. . At this time, the pressure sensor PT installed on the first fuel gas supply line SL1-2 and the second fuel gas supply line SL2 entering the engine room E/R is connected to the engine room E/R. ), so that the explosion-proof design is not applied, and thus cost reduction can be expected.

On the first vacuum suction line IL1, the second vacuum suction line IL2 and the third vacuum suction line IL3, respectively, the first vacuum control valve IV1, the second vacuum control valve IV2 and the third vacuum control A valve IV3 may be installed. The first vacuum control valve IV1, the second vacuum control valve IV2 and the third vacuum control valve IV3 are the fuel supply line FL, the first fuel gas supply line SL1-2 and the second fuel gas When the vacuum of the outer tube of the supply line SL2 is completely formed, it may be blocked.

In addition, a nitrogen control valve (NV) for controlling the supply of nitrogen gas from the nitrogen supply unit 400 to the ejector 500 side may be installed on the nitrogen supply line NL, and as vacuum formation is completed, the first to third When the vacuum control valves IV1, IV2, and IV3 are blocked, the nitrogen control valve NV is also blocked to stop the consumption of nitrogen gas, thereby saving energy.

A three-way valve (3V) may be installed on the vacuum injection line (IL4). When vacuum is formed in the fuel supply line (FL), the first fuel gas supply line (SL1-2), and the second fuel gas supply line (SL2), the three-way valve (3V) releases the fluid sucked into the ejector 500 to the outside ( It is open to discharge to the overboard).

On the other hand, in the present invention, nitrogen gas discharged to the vacuum injection line (EL) is charged into the external pipes of the fuel supply line (FL), the first fuel gas supply line (SL1-2), and the second fuel gas supply line (SL2). It may further include a nitrogen filling line (CL1, CL2, CL3) for this.

The nitrogen filling lines (CL1, CL2, CL3) are branched from the point where the three-way valve (3V) is installed on the vacuum injection line (EL), respectively, the fuel supply line (FL) and the first fuel gas supply line (SL1-2) and an external pipe of the second fuel gas supply line SL2.

When leakage of the inner pipe occurs in any one or more of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2, the nitrogen supply unit 400 The nitrogen gas supplied to the ejector 500 is not discharged to the outside (outboard) through the vacuum injection line EL, but is supplied through the nitrogen filling lines CL1, CL2, CL3 to the external pipe of the leaked line. do.

At this time, since the outer tube of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 has a vacuum, it can be quickly replaced with nitrogen gas in a vacuum state. have. In addition, the ejector 500 may serve to help the outer tube of the leaked line to be replaced with nitrogen gas more quickly.

A first nitrogen filling valve (CV1), a second nitrogen filling valve (CV2), and a third nitrogen on the first nitrogen filling line (CL1), the second nitrogen filling line (CL2) and the third nitrogen filling line (CL3), respectively A charging valve (CV3) may be installed. The first to third nitrogen filling valves CV1, CV2, and CV3 are normally closed, so that the outside of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 It allows the tube to maintain a vacuum state, and is opened only when the outer tube is replaced with nitrogen gas.

When a leak occurs in the inner tubes of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2, the operation of replacing the outer tube with nitrogen gas is as follows. can be done together.

First, the vacuum control valves IV1 , IV2 , and IV3 on the side of the leaking line are opened, and compressed nitrogen gas is supplied from the nitrogen supply unit 400 to the nitrogen supply line NL to operate the ejector 500 . Accordingly, the leaked gas is sucked into the ejector 500 through the vacuum suction lines IL1, IL2, IL3 and then discharged to the outside (outboard) through the vacuum injection line EL.

When it is determined that the discharge of the leaked gas is complete, the nitrogen filling valves (CV1, CV2, CV3) on the side of the leaked line are opened, and nitrogen gas is filled into the external pipe of the leaked line at a certain pressure or more.

Thereafter, the three-way valve (3V) is switched to the direction toward the nitrogen filling lines (CL1, CL2, CL3) on the side of the leaking line to quickly replace the outer tube of the leaking line with nitrogen gas. At this time, the three-way valve (3V) is opened as much as possible to remove all the gas in the outer tube of the leaking line, and then the direction is switched to the nitrogen filling line (CL1, CL2, CL3).

When the operation of replacing the outer tube of the leaked line with nitrogen gas is completed, the vacuum control valves IV1, IV2, IV3 and the nitrogen filling valves CV1, CV2, and CV3 are cut off. The completion of replacement of the line can be confirmed through the pressure sensor (PT) installed in each line.

On the other hand, the first vacuum suction line IL1 and the nitrogen filling line CL1 connected to the fuel supply line FL are connected to the end and the end of the fuel supply line FL, respectively, that is, the first vacuum suction line It is desirable to induce smooth circulation by placing the connection point between (IL1) and the nitrogen filling line (CL1) as far apart as possible. This concept may be equally applied to the first fuel gas supply line SL1 - 2 or the second fuel gas supply line SL2 .

When the leakage of LNG gas occurs as described above, the engines 110 and 120 connected to the line in which the leakage occurs cannot operate any longer in the gas mode. In this case, the operation of stopping the supply of LNG gas by the fuel supply unit 300 and purging the engines 110 and 120 should be performed.

In the present invention, the purging operation of the engines 110 and 120 may be performed by nitrogen gas supplied from the nitrogen supply unit 400 through the purging lines PL1 and PL2.

Specifically, the nitrogen supply unit 400 is connected to the gas engine 110 and the main engine 120 through the first purging line PL1 and the second purging line PL2, respectively, and purging the engines 110 and 120 . If necessary, nitrogen gas is directly supplied to the engines 110 and 120 . A first purging valve PV1 and a second purging valve PV2 for controlling the supply of nitrogen gas from the nitrogen supply unit 400 to the engines 110 and 120 on the first purging line PL1 and the second purging line PL2 ) can be installed.

The nitrogen gas supplied to the engines 110 and 120 through the purging lines PL1 and PL2 pushes the residual gas inside the engines 110 and 120, and the residual gas is pushed to the nitrogen gas and discharged from the engines 110 and 120. may be discharged to a safe area (eg, outside air) via GVU 310 or GVT 320 .

Specifically, the residual gas discharged from the gas engine 110 during purging of the gas engine 110 is discharged in the opposite direction to the direction in which the fuel gas is supplied through the first fuel gas supply line SL1-2, and the GVU ( 310) and may be discharged to a safe area through the third vent line VL3. A vent valve VV3 for opening and closing the line may be installed on the third vent line VL3.

Similarly, the residual gas discharged from the main engine 120 during purging of the main engine 120 is discharged in the opposite direction to the direction in which the fuel gas is supplied through the second fuel gas supply line SL2, and the GVT (320) may be discharged to a safe area through

Conventionally, in order to purify the interior of an engine using LNG fuel, a purging gas (eg, nitrogen gas) is supplied to a pipe to which LNG gas is supplied, and the residual gas discharged from the engine passes through an exhaust line through which the exhaust gas is discharged. It was discharged through a vent mast.

Therefore, in the prior art, purging of the engine was performed in the direction of the fuel gas supply line → engine → safe area. The gas pipe passing through the engine room classified as a zone had a disadvantage in terms of cost because it had to be composed of a double pipe or enclosed with a duct.

However, in the present invention, by directly supplying nitrogen gas from the nitrogen supply unit 400 to the engines 110 and 120, purging of the engine is performed in the engine (110, 120) → GVU (310) or GVT (320) → Safe Area direction. it can be seen that the That is, the purging of the engines 110 and 120 is performed in the opposite direction to the conventional one.

According to the present invention, it is possible to discharge the residual gas discharged from the engine 100 using the first fuel gas supply line SL1-2 or the second fuel gas supply line 'already composed of a double pipe'). As a result, the utilization of the existing equipment is increased, and there is no need to provide a separate gas pipe for discharging residual gas inside the engine room (E/R), so it is possible to reduce the cost due to the reduction in quantity.

In addition, the gas piping placed inside the engine room (E/R), where a lot of electrical equipment, oil handling equipment, and ignition equipment are placed, has the effect of maximizing stability, and cargo compressor classified as a gas hazardous area Since the room 10 and the GVU room 20 are constantly exchanging air 30 times per hour, it is very advantageous for ventilation to discharge the residual gas of the engines 110 and 120 using the corresponding area.

The purging operation of the engines 110 and 120 as described above is performed not only when the leakage of LNG gas occurs, but also when the operation of the engines 110 and 120 is stopped for a long time or the internal system is to be maintained, or the engines 110 and 120 Of course, it can be applied to the case where the used fuel of ) is to be changed from LNG to fuel oil.

Meanwhile, in the present invention, by installing the second eductor 620 on the third vent line VL3 extending from the GVU 310 , the purging operation of the gas engine 110 can be performed more quickly.

Regarding the installation and operation of the second eductor 620 , the technical idea described in the above-described first eductor 610 may be applied almost identically.

Specifically, the second eductor 620 may be installed to be connected to the rear end of the exhaust fan F2, and on the line connecting the second eductor 620 and the exhaust fan F2, a second non-return valve (BV) is installed to separate the second eductor 620 from the exhaust fan F2 or to prevent pressure loss from the second eductor 620 toward the exhaust fan F2.

A second pressure supply line OL2 for supplying nitrogen gas from the nitrogen supply unit 400 to the second eductor 620 may be connected to the second eductor 620 , and nitrogen gas is provided on the second pressure supply line OL2 . A second pressure control valve OV2 for controlling the supply of gas may be installed.

The second eductor 620 may be operated individually or simultaneously with the exhaust fan F2, and when operated individually, the compressed nitrogen gas supplied from the nitrogen supply unit 400 is supplied as a driving fluid, and the exhaust fan When operated together with (F2), it is operated by receiving the positive pressure formed by the exhaust fan (F2), or at the same time, nitrogen gas provided from the nitrogen supply unit 400 can be additionally supplied as a driving fluid. As described in the first eductor 610 .

As described above, according to the present invention, when the GVU room 20 is ventilated, the second eductor 620 is installed to increase the ventilation efficiency and reduce the power consumption of the exhaust fan F2 . In particular, when the second eductor 620 is operated using the pressure of the nitrogen gas supplied from the nitrogen supply unit 400, the power consumption of the exhaust fan F2 can be significantly reduced compared to the prior art, thereby reducing the OPEX Alternatively, the exhaust fan F2 can be completely eliminated, thereby reducing the CAPEX.

In addition, according to the present invention, it is possible to discharge the residual gas inside the gas engine 110 to a desired area by using the pressure formed in the second eductor 620 . According to the existing design, the vent pipe of the gas pipe should be positioned high, and there was a restriction to use a large pipe in consideration of the pressure drop. When the present invention is applied, the second eductor Since it is possible to discharge the residual gas to a desired area by using the pressure formed in 620, it is possible to arrange the third vent line (VL3) in any position as long as it is a safe area, which has advantages in piping design and cost reduction. effect is expected.

As described above, in the present invention, the nitrogen supply unit 400 may have the following five roles.

1) A role of supplying nitrogen gas to the pressurizing unit 210 in order to control the internal pressure of the fuel tank 100 .

2) nitrogen gas as a driving fluid of the ejector 500 to form the outer tubes of the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 in a vacuum state role in supplying

3) A role of supplying nitrogen gas to fill the outer pipe when the fuel supply line FL, the first fuel gas supply line SL1-2, and the second fuel gas supply line SL2 leak.

4) The role of supplying nitrogen gas as a purging gas of the engines (110, 120).

5) A role of supplying nitrogen gas to provide pressure to the eductors 610 and 620 installed for ventilation of the cofferdam 30 or the GVU room 20 .

For the above roles, the nitrogen supply unit 400 of the present invention is a nitrogen generator (N2 Generator) for generating nitrogen, a nitrogen buffer tank (N2 Buffer Tank) for temporarily storing nitrogen generated by the nitrogen generator to control the supply ), a nitrogen compressor (N2 Compressor) for compressing nitrogen gas, etc. may be included, and may be disposed inside the engine room (E/R).

In addition, although nitrogen gas, which is a representative inert gas, has been described as an example in order to construct a safe system in the present invention, it is of course possible to use other inert gas having little chemical action in addition to nitrogen gas.

The present invention is not limited to the described embodiments, and it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, it should be said that such modifications or variations belong to the claims of the present invention.

110: gas engine
120: main engine
200: fuel tank
210: pressurization unit
300: fuel supply unit
310: GVU
320: GVT
400: nitrogen supply unit
500: ejector
610: first eductor
620: second eductor
ML: pressure holding line
FL: fuel supply line
SL1: first fuel gas supply line
SL2: second fuel gas supply line
NL: nitrogen supply line
IL1: first vacuum suction line
IL2: second vacuum suction line
IL3: 3rd vacuum suction line
EL: vacuum injection line
3V: three-way valve
CL1: first nitrogen filling line
CL2: second nitrogen filling line
CL3: third nitrogen filling line
PL1: first purging line
PL2: 2nd purging line
OL1: first pressure supply line
OL2: second pressure supply line
OV1: first pressure control valve
OV2: second pressure control valve
VL1: first vent line
VL2: second vent line
VL3: 3rd vent line

Claims (16)

a main engine that can be driven using fuel gas and is provided as an engine for propulsion of a ship;
a fuel tank in which the fuel gas is stored;
a fuel supply unit supplying the fuel gas stored in the fuel tank according to the conditions required by the main engine;
a gas valve train (GVT) that finally controls the pressure and flow rate of the fuel gas compressed in the fuel supply unit and supplies it to the main engine; and
and a high-pressure fuel gas supply line connected from the GVT to the main engine and provided with a double pipe,
The high-pressure fuel gas supply line is characterized in that the outer tube is formed in a vacuum so that the outer tube can be quickly replaced with nitrogen gas when a leak occurs in the inner tube,
Ship's fuel gas supply system. The method according to claim 1,
an ejector that sucks in the gas present in the outer tube to form a vacuum; and
Further comprising a nitrogen supply unit for supplying compressed nitrogen gas as a driving fluid of the ejector,
Ship's fuel gas supply system. 3. The method according to claim 2,
a vacuum suction line for sucking the gas inside the outer tube toward the ejector;
a vacuum injection line for discharging the gas sucked into the ejector through the vacuum suction line to an outboard; and
Further comprising a nitrogen supply line for supplying the compressed nitrogen gas from the nitrogen supply to the ejector,
Ship's fuel gas supply system. 4. The method according to claim 3,
a three-way valve installed on the vacuum injection line; and
Further comprising a nitrogen filling line branched from the vacuum injection line at the point where the three-way valve is installed and connected to the external pipe,
When the inner tube leaks, the three-way valve is switched in a direction toward the nitrogen filling line, characterized in that the nitrogen gas supplied from the nitrogen supply unit to the ejector is filled into the outer tube,
Ship's fuel gas supply system. 5. The method according to claim 4,
The vacuum suction line and the nitrogen filling line are connected to the ends and ends of the high-pressure fuel gas supply line, respectively, so that the vacuum suction line and the nitrogen filling line are formed as far apart as possible from the connection point to ensure smooth circulation of the outer tube characterized by inducing
Ship's fuel gas supply system. 3. The method according to claim 2,
The nitrogen supply unit, characterized in that for supplying nitrogen gas as a purging gas for purging of the main engine,
Ship's fuel gas supply system. 7. The method of claim 6,
Further comprising a purging line for supplying the nitrogen gas from the nitrogen supply unit for the purpose of purging the main engine,
The nitrogen gas supplied to the purging line is supplied to the main engine to purify the inside of the main engine and the high-pressure fuel gas supply line, and then is discharged to the outside air through the GVT,
Ship's fuel gas supply system. 8. The method of claim 7,
The fuel supply unit and the GVT are arranged in a cargo compressor room (Cargo Compressor Room), characterized in that the cargo compressor room is located in the cargo area of the ship,
Ship's fuel gas supply system. 9. The method of claim 8,
The cargo compressor room is characterized in that it is classified as a gas hazardous zone (Gas Hazardous Zone) where ventilation is made periodically,
Ship's fuel gas supply system. 9. The method of claim 8,
The cargo area is characterized in that it is located in front of the engine room of the stern part where the main engine is disposed,
Ship's fuel gas supply system. 11. The method of claim 10,
Further comprising a cofferdam partition provided on the boundary surface of the engine room and the cargo area,
The high-pressure fuel gas supply line passes through the inside of the cofferdam and passes through the front bulkhead of the engine room, characterized in that it is connected to the main engine,
Ship's fuel gas supply system. 12. The method of claim 11,
The cofferdam is characterized in that periodic ventilation is performed with respect to the internal space,
Ship's fuel gas supply system. 13. The method of claim 12,
an exhaust fan installed on a first vent line for discharging air inside the cofferdam; and
Further comprising an eductor installed on a second vent line for discharging the air inside the cofferdam,
Ventilation inside the cofferdam is characterized in that it is made by selectively operating the exhaust fan and the eductor individually or simultaneously.
Ship's fuel gas supply system. 14. The method of claim 13,
When the eductor is individually operated, the eductor is operated by receiving pressure from the compressed nitrogen gas supplied from the nitrogen supply unit,
Ship's fuel gas supply system. 15. The method of claim 14,
In the case of performing ventilation inside the cofferdam using only the eductor, it is possible to delete the exhaust fan,
Ship's fuel gas supply system. 14. The method of claim 13,
When the exhaust fan and the eductor are simultaneously operated, the eductor is operated by receiving at least one of a pressure formed by the exhaust fan and a pressure of compressed nitrogen gas supplied from the nitrogen supply unit ,
Ship's fuel gas supply system.

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