WO2021256644A1 - Système et procédé permettant d'alimenter en carburant un transporteur de gaz liquéfié - Google Patents

Système et procédé permettant d'alimenter en carburant un transporteur de gaz liquéfié Download PDF

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Publication number
WO2021256644A1
WO2021256644A1 PCT/KR2020/018576 KR2020018576W WO2021256644A1 WO 2021256644 A1 WO2021256644 A1 WO 2021256644A1 KR 2020018576 W KR2020018576 W KR 2020018576W WO 2021256644 A1 WO2021256644 A1 WO 2021256644A1
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WIPO (PCT)
Prior art keywords
liquefied gas
fuel supply
pressure
pump
engine
Prior art date
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PCT/KR2020/018576
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English (en)
Korean (ko)
Inventor
김두혁
최안철
박성호
태혁준
이규성
Original Assignee
대우조선해양 주식회사
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Publication date
Priority claimed from KR1020200074179A external-priority patent/KR102327410B1/ko
Priority claimed from KR1020200118376A external-priority patent/KR20220036446A/ko
Application filed by 대우조선해양 주식회사 filed Critical 대우조선해양 주식회사
Priority to JP2022575940A priority Critical patent/JP7485796B2/ja
Priority to CN202080101981.2A priority patent/CN115697836A/zh
Publication of WO2021256644A1 publication Critical patent/WO2021256644A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B17/00—Vessels parts, details, or accessories, not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
    • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
    • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
    • B63B25/12—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed
    • B63B25/16—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed heat-insulated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H21/00—Use of propulsion power plant or units on vessels
    • B63H21/38—Apparatus or methods specially adapted for use on marine vessels, for handling power plant or unit liquids, e.g. lubricants, coolants, fuels or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63J—AUXILIARIES ON VESSELS
    • B63J2/00—Arrangements of ventilation, heating, cooling, or air-conditioning
    • B63J2/12—Heating; Cooling
    • B63J2/14—Heating; Cooling of liquid-freight-carrying tanks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C6/00—Methods and apparatus for filling vessels not under pressure with liquefied or solidified gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C9/00—Methods or apparatus for discharging liquefied or solidified gases from vessels not under pressure
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

Definitions

  • the present invention relates to a fuel supply system and method for a liquefied gas carrier, and more particularly, to a fuel supply for a liquefied gas carrier that recovers and recirculates the remaining LPG from a ship using a liquefied gas such as LPG as a fuel to an engine in excess. It relates to systems and methods.
  • Liquefied gas such as LNG (Liquefied Natural Gas) or LPG (Liquefied Petroleum Gas)
  • LNG Liquefied Natural Gas
  • LPG Liquefied Petroleum Gas
  • Liquefied gas is transported in a gaseous state through a gas pipeline on land or offshore, or stored in a liquefied gas carrier in a liquefied state and transported to a remote consumer.
  • Liquefied gas such as LNG or LPG is obtained by cooling natural gas or petroleum gas to cryogenic temperatures (approximately -163°C in the case of LNG).
  • the liquefaction temperature of petroleum gas is a low temperature of about -42°C under normal pressure, and can be stored in a liquid state up to a temperature of about 45°C at 18 bar and 20°C at 7 bar. Since LPG evaporates when the atmospheric pressure is higher than -42°C, the LPG storage tank of the ship is insulated. However, since external heat is continuously transferred to the LPG, the LPG is continuously vaporized in the LPG storage tank during the LPG transportation process, thereby generating boil-off gas in the LPG storage tank.
  • LPG is easier to store than LNG, which is liquefied at cryogenic temperatures, and it does not significantly fall in SPECIFIC ENERGY and ENERGY DENSITY compared to conventional HFO, and has an excellent effect in reducing SOX, NOX, CO2, PM, etc. compared to conventional HFO.
  • FIG. 1 An example of a fuel supply system from a ship using LPG as a fuel to a conventional engine is schematically shown in FIG. 1 .
  • LPG to be supplied as fuel to the engine E is supplied from the fuel supply tank according to the fuel supply conditions of the engine through a fuel supply system including a compression pump and a heater. It is supplied to the engine of the ship via line L1.
  • LPG an incompressible fluid
  • LPG can be supplied in excess of the fuel required by the engine to respond immediately to changes in engine load. It is withdrawn from the engine upstream of the engine via line L2.
  • An object of the present invention is to provide a system capable of efficiently supplying fuel while effectively processing LPG recovered from an engine by solving this problem.
  • a fuel supply line through which liquefied gas is supplied from a fuel supply tank provided on the deck of a ship to an onboard engine
  • a compression unit provided in the fuel supply line and compressing the liquefied gas to be supplied to the onboard engine to a pressure required for the engine;
  • the liquefied gas recirculated through the return line is cooled by the reduced pressure in the decompression unit, and there is provided a fuel supply system for a liquefied gas carrier, characterized in that it is introduced into the separator.
  • the compression unit comprises: a first pump for pumping and transferring liquefied gas from the fuel supply tank; and a second pump for pumping the liquefied gas transferred from the first pump to increase the pressure to a required pressure in the engine, wherein the liquid liquefied gas separated from the separator is a fuel between the first pump and the second pump It can be supplied to the supply line and recycled.
  • a vapor line for recovering the gas separated from the separator to the fuel supply tank; and a pressure control valve provided in the vapor line.
  • the pressure of the rear end of the first pump is sensed, and the opening degree of the pressure control valve is adjusted according to the sensed pressure to maintain the pressure of the separator 0.5 to 2 bar higher than the pressure at the rear end of the first pump. have.
  • a fuel heater provided at the rear end of the compression unit in the fuel supply line and heating the compressed liquefied gas to a temperature required by the engine; may further include.
  • the return line includes: a first return line connected from the engine to the separator; and a second return line connected to the separator from a fuel supply line between the second pump and the fuel heater.
  • the pressure reducing unit includes: a first pressure reducing device provided in the first return line; and a second pressure reducing device provided on the second return line.
  • the pump speed of the second pump is lowered first, and if it is still higher than the set value, the second pressure reducing device is opened to increase the pressure of the second pump.
  • the back pressure can be lowered.
  • the re-liquefaction unit for receiving the boil-off gas generated from the cargo tank for storing the liquefied gas to be transported provided on the ship and re-liquefied; and a cooling line connected from the reliquefaction unit to the cargo tank via the fuel supply tank, wherein the liquefied gas reliquefied in the reliquefaction unit cools the fuel supply tank along the cooling line and the cargo tank can be transferred to
  • a fuel tank provided in the ship to store the liquefied gas to be supplied to the onboard engine may further include, wherein the liquefied gas is transferred from the fuel tank to the fuel supply tank to cool the fuel supply tank .
  • a discharge pipe provided at the bottom of the separator for separating and discharging the lubricating oil mixed in the liquefied gas returned to the separator; and a re-liquefaction unit for re-liquefying boil-off gas generated from a cargo tank for storing liquefied gas to be transported and provided on the ship, wherein the liquefied gas re-liquefied in the re-liquefaction unit passes through the fuel supply tank to the cargo tank By transport, it is possible to cool the fuel supply tank.
  • the liquefied gas is compressed in the compression unit along the fuel supply line from the fuel supply tank provided on the deck of the ship and supplied as fuel to the onboard engine,
  • a decompression unit is provided in a return line for recirculating liquefied gas not consumed by the engine among the liquefied gas compressed in the compression unit to an upstream side of the engine to reduce the pressure of the liquefied gas to be recirculated, and the recirculated liquefied gas cooled by the reduced pressure in the separator
  • a fuel supply method for a liquefied gas carrier characterized in that gas-liquid separation.
  • the compression unit comprises: a first pump for pumping and transferring liquefied gas from the fuel supply tank; and a second pump for pumping the liquefied gas transferred from the first pump to increase the pressure to a required pressure in the engine, wherein the liquid liquefied gas separated from the separator is a fuel between the first pump and the second pump It can be supplied to the supply line and recycled.
  • the gas separated from the separator is recovered to the fuel supply tank, by detecting a rear end pressure of the first pump, and adjusting the amount of gas recovered to the fuel supply tank according to the sensed pressure,
  • the pressure of the separator may be maintained 0.5 to 2 bar higher than the pressure at the rear end of the first pump.
  • the pressure at the rear end of the second pump may be lowered by reducing the pressure and discharging it to the separator.
  • the boil-off gas generated from the cargo tank for storing the liquefied gas to be transported provided in the ship is reliquefied in the reliquefaction unit, and the liquefied gas reliquefied in the reliquefaction unit passes through the fuel supply tank to the fuel supply tank It can be cooled and transferred to the cargo tank.
  • the fuel supply tank can be cooled by transferring the liquefied gas to the fuel supply tank from a fuel tank that is provided in the ship to store the liquefied gas to be supplied to the onboard engine.
  • a discharge pipe for separating and discharging the lubricant mixed in the liquefied gas returned to the separator may be provided at the bottom of the separator.
  • the boil-off gas generated from the cargo tank for storing the liquefied gas to be transported provided in the ship is reliquefied in the reliquefaction unit, and the liquefied gas reliquefied in the reliquefaction unit is passed through the fuel supply tank to the cargo tank. It can be transferred to cool the fuel supply tank.
  • the liquefied gas not consumed in the engine is recirculated through the return line among the compressed liquefied gas for fuel supply to the engine, and the compressed liquefied gas is cooled in the return line at reduced pressure and separated from the gas-liquid through a separator to liquefy the liquid. Only gas is supplied to the fuel supply line to be recirculated. In this way, by recirculating the remaining liquefied gas that is oversupplied to the engine and consumed as fuel, it is possible to prevent lubricating oil from being mixed into the fuel, thereby preventing incomplete combustion of the engine and the generation of pollutants in the exhaust due to the incomplete combustion of the engine. It can prevent LPG contamination and crystallization of lubricating oil in the fuel supply tank.
  • the second pump suction of the compression unit It is possible to reduce the risk of vapor generation and prevent device failure of the compression unit without installing additional equipment to remove it.
  • the gas separated from the separator is transferred to the fuel supply tank, and the boil-off gas generated in the cargo tank is reliquefied and transferred to the cargo tank through the fuel supply tank through the cooling line. By cooling, the pressure and temperature of the tank can be safely maintained.
  • FIG. 1 schematically shows a fuel supply system from a ship equipped with an engine using LPG as a fuel to a conventional engine.
  • FIG. 2 schematically shows a fuel supply system for a liquefied gas carrier according to a first embodiment of the present invention.
  • FIG. 3 schematically shows a fuel supply system for a liquefied gas carrier according to a second embodiment of the present invention.
  • FIG. 4 schematically shows the configuration of a discharge unit for discharging lubricant oil from a separator in a fuel supply system of a liquefied gas carrier according to a second embodiment of the present invention.
  • the vessel may be any type of vessel in which an engine capable of using liquefied petroleum gas as a fuel for a propulsion engine or a fuel for a power generation engine is installed.
  • Typical examples include ships with self-propelled capabilities such as LPG carriers, LNG carriers, liquid hydrogen carriers, and LNG RVs (Regasification Vessels), LNG Floating Production Storage Offloading (FPSO), and LNG FSRU (Floating Storage Regasification Unit). It may also include offshore structures that do not have propulsion capabilities, but are floating in the sea.
  • this embodiment can be transported by being liquefied at a low temperature, and BOG is generated in a stored state and can be applied to a fuel supply system of all kinds of liquefied gas that can be supplied as fuel of an engine.
  • liquefied gas is, for example, liquefied petrochemicals such as LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), Liquefied Ethylene Gas, Liquefied Propylene Gas, etc. gas and ammonia, and the like.
  • LNG Liquefied Natural Gas
  • LEG Liquefied Ethane Gas
  • LPG Liquefied Petroleum Gas
  • Liquefied Ethylene Gas Liquefied Propylene Gas
  • ammonia and the like.
  • LPG which is one of representative liquefied gases
  • FIG. 2 schematically shows a fuel supply system for a liquefied gas carrier according to a first embodiment of the present invention.
  • the fuel supply system of the first embodiment includes a fuel supply line (SL) through which liquefied gas is supplied from a fuel supply tank (DT) provided on the deck of the ship to the in-board engine (E), and a fuel supply line Compression units 110 and 120 for compressing the liquefied gas to be supplied to the onboard engine to the pressure required for the engine, and a return line RL1 for recirculating the liquefied gas not consumed in the engine among the liquefied gas to the upstream of the engine.
  • RL2 a separator 210 provided in the return line for gas-liquid separation of the recirculated liquefied gas
  • pressure reducing units 220 and 230 provided upstream of the separator in the return line.
  • the liquefied gas recirculated through the return line is decompressed through the decompression unit, and the liquefied gas is cooled by the Joule-Thomson effect in the decompression process and introduced into the separator.
  • the compression unit includes a first pump 110 for pumping and transferring the liquefied gas from the fuel supply tank, and a second pump 120 for pumping the liquefied gas transferred from the first pump and boosting the pressure to the pressure required by the engine. It consists of two pumps.
  • the first pump 110 is a low-pressure pump for transporting liquefied gas and is a centrifugal pump
  • the second pump 120 is a high-pressure pump that compresses the fuel supply pressure required by the engine, and is a diaphragm pump.
  • the liquefied gas passing through the first and second pumps is heated to a temperature required by the engine in the fuel heater 130 provided at the rear end of the compression unit in the fuel supply line and supplied to the engine.
  • the compressed and heated liquefied gas through the compression unit and the fuel heater is supplied to the engine E through the filter 140 that filters out foreign substances in the fuel and the service valve unit SVT.
  • the service valve part while supplying LPG to the engine, when LPG fuel supply is stopped due to engine fuel oil switching, LPG mode stop, trip, etc., each pipe is double-blocked through the valve to relieve pressure in the pipe.
  • An engine receiving such compressed and heated LPG as fuel may be, for example, a ME-LGIP engine of MAN Diesel & Turbo.
  • LPG is supplied to the engine in a high-pressure liquid state of around 54 bar and 35° C. through the compression unit and the fuel heater, and the engine is operated by being hydraulically injected into the nozzle at a pressure of 600 to 700 bar.
  • compressed and heated fuel is supplied to the engine in a liquid state, and unlike the engine to which a compressible fluid having a large volume change according to a change in pressure, that is, gas fuel is supplied, the volume changes even when pressure is applied.
  • a compressible fluid having a large volume change according to a change in pressure that is, gas fuel is supplied
  • sufficient fuel is supplied to respond immediately to changes in engine load and excess LPG is supplied to the engine to prevent cavitation.
  • the remaining LPG consumed as fuel is discharged from the engine through the return line and recirculated. ), and may pose a threat to tank and ship safety by increasing the pressure and temperature in the fuel supply tank.
  • the decompression units 220 and 230 for decompressing the liquefied gas are provided in the return line, so that the liquefied gas discharged from the engine can be recirculated by decompressing the liquefied gas.
  • the compressed liquefied gas is cooled by the Joule-Thomson effect while undergoing adiabatic or isentropic expansion during the decompression process.
  • the compressed liquefied gas recirculated from the engine E through the return line RL1 is reduced in pressure through the decompression unit 220 and cooled, introduced into the separator 210 for gas-liquid separation, and the liquid liquefied gas separated from the separator is It is supplied to the fuel supply line SL between the first pump 110 and the second pump 120 through the liquid line LL and recirculated, and the gas separated from the separator is supplied to the fuel supply tank through the vapor line VL. (DT) is recovered.
  • the vapor line is provided with a pressure control valve 250 for controlling the gas transferred to the fuel supply tank (DT).
  • the liquefied gas cooled through decompression is introduced into the separator, and the liquid liquefied gas after gas-liquid separation is supplied from the fuel supply tank through the first pump of the compression unit through the first pump of the compression unit and the second pump 120 together with the subcooled LPG. ), it is possible to reduce the risk of vapor generation in the suction part of the second pump and not configure a separate device for vapor removal.
  • the fuel heater when the temperature of the recirculated liquefied gas is high, the fuel heater must have a cooling function as well as a heating function in order to meet the fuel requirements of the engine.
  • the gas in the decompressed recirculation liquefied gas is recovered to the fuel supply tank, and the mass flow of the high-temperature recirculated liquefied gas sucked into the second pump is reduced, so that fuel at an appropriate temperature can be supplied to the engine without additional cooling. Since the fuel heater only needs to have a heating function, the equipment cost can be reduced and operation is easy.
  • the return line includes a first return line RL1 connected from the engine E to the separator 210 and a separator ( and a second return line RL2 connected to 210 .
  • the decompression unit may include a first decompression device 220 provided in the first return line and a second decompression device 230 provided in the second return line.
  • the first and second pressure reducing devices may include an expander for cooling the compressed liquefied gas by adiabatic or isentropic expansion or an expansion valve such as a Joule-Thomson valve.
  • a return valve unit (RVT) and a filter 240 are provided upstream of the first pressure reducing device in the first return line, and the liquefied gas discharged from the engine is introduced into the first pressure reducing device through the return valve unit and the filter.
  • the filter can filter lubricating oil mixed in the liquefied gas discharged from the engine.
  • the first return line and the first pressure reducing device depressurize the liquefied gas discharged from the engine, and the second return line and the second pressure reducing device decompress the compressed liquefied gas through the compression units of the first and second pumps from upstream of the fuel heater to form a separator. transfer to
  • the LPG remaining in the engine and fuel supply line can also be cooled under reduced pressure and transferred to the separator when the LPG fuel supply is interrupted, such as when the engine is stopped in LPG mode or when tripping.
  • the LPG fuel supply is stopped, it is not necessary to recirculate the LPG from the separator to the fuel supply line, so it can be sent to the fuel supply tank, and for this, a transfer line (not shown) from the separator to the fuel supply tank may be provided.
  • a plurality of pressure sensing units are provided to control the operating pressure.
  • a first pressure sensing unit PC1 that senses the pressure between the second pump and the fuel heater and sends a pressure signal
  • a second pressure sensing unit that senses the pressure between the filter and the first pressure reducing device in the first return line and sends a pressure signal
  • a unit PC2 a third pressure sensing unit PC3 sensing the pressure of the rear end of the first pump, and a fourth pressure sensing unit PC4 sensing the pressure of the separator are provided, respectively.
  • the operating pressure in the system of the present embodiment may be controlled as follows, for example.
  • the operating pressure range of the fuel supply tank is 1 to 8 barg. Assuming that the operating pressure is 4 barg, the differential pressure of the first pump is about 2 bar, and the rear end pressure of the first pump is 6 barg.
  • the operating pressure of the separator 210 is maintained at about 0.5 to 2 bar, more preferably 0.5 to 1 bar higher than the pressure at the rear end of the first pump, so that the liquid recirculation gas separated from the separator is smoothly transferred to the rear end of the first pump.
  • the fourth pressure sensing unit PC4 receives the pressure signal from the third pressure sensing unit PC3, and the fourth pressure sensing unit PC4 sets the set value to the pressure control valve 250 of the vapor line VL.
  • the pressure of the separator is maintained at 6.5 to 7 barg.
  • the liquid separated from the separator is supplied to the front end of the second pump along the liquid line LL, and is pumped from the second pump and pressurized to 54 barg.
  • the first return line RL1 returning from the engine controls the first pressure reducing device 220 from the second pressure sensing unit to maintain the pressure upstream of the first pressure reducing device at 22 barg, and the pressure at the rear end of the first pressure reducing device is Maintain at 6.5 to 7 barg equal to the separator pressure.
  • the pressure is sensed by the first pressure sensing unit PC1 and is higher than the set value (54 barg) of the first pressure sensing unit.
  • the pump speed is lowered by adjusting the VFD, and if the pressure is still increased from 54 barg or more to 55 barg, the second pressure reducing device 230 of the second return line is opened to lower the pressure.
  • the ship of this embodiment is provided with a cargo tank (not shown) for storing and transporting liquefied gas as a liquefied gas carrier, and the boil-off gas generated from the liquefied gas stored in the cargo tank is supplied to the re-liquefaction unit (RS) and re-liquefied. .
  • a cargo tank (not shown) for storing and transporting liquefied gas as a liquefied gas carrier, and the boil-off gas generated from the liquefied gas stored in the cargo tank is supplied to the re-liquefaction unit (RS) and re-liquefied.
  • the temperature of the fuel supply tank may be increased by the gas separated from the separator and introduced.
  • the liquefied gas reliquefied from the reliquefaction unit RS passes through the fuel supply tank DT to the cargo tank (not shown).
  • a cooling line CL is provided so as to be connected, so that the fuel supply tank can be cooled by using the cooling heat of the liquefied gas reliquefied in the reliquefaction unit.
  • fuel tanks FT1 and FT2 for supplying liquefied gas to be supplied as fuel of the onboard engine to the fuel supply tank DT disposed on the deck are additionally provided. It is also possible to supply liquefied gas from the fuel supply tank to the fuel supply tank to cool the fuel supply tank by the low-temperature liquefied gas.
  • FIG. 3 schematically shows a fuel supply system for a liquefied gas carrier according to a second embodiment of the present invention.
  • the fuel supply system of the second embodiment also includes a fuel supply line SL through which liquefied gas is supplied from the fuel supply tank DT provided on the deck of the ship to the in-board engine E, and the fuel supply A first pump 110 provided in the line and transferring liquefied gas to be supplied from the fuel supply tank to the engine, a second pump 120 provided in the fuel supply line and compressing the liquefied gas to the pressure required for the engine, among the liquefied gas Return lines RL1 and RL2 for recirculating the liquefied gas not consumed in the engine to the upstream of the engine, the separator 210 provided in the return line and receiving the recirculated liquefied gas to gas-liquid separation, the liquid liquefied gas separated from the separator It includes a liquid line LL for supplying to the rear end of the first pump of the fuel supply line, and a vapor line VL for recovering the gas separated from the separator to the fuel supply tank DT.
  • a liquid line LL for supplying to the rear end of
  • a pressure reducing unit for reducing the recirculated liquefied gas is provided upstream of the separator in the return line, and a pressure regulating valve 250 for controlling the gas transferred to the fuel supply tank DT is provided in the vapor line connected from the separator to the fuel supply tank.
  • Amount of gas recovered from the separator to the fuel supply tank by sensing the pressure at the rear end of the first pump of the fuel supply line to which the liquefied gas separated from the separator and recirculated through the liquid line is supplied, and by controlling the pressure control valve according to the sensed pressure by adjusting the pressure of the separator to be maintained higher than the pressure sensed in the fuel supply line.
  • the fuel supply from the fuel supply tank to the engine includes a first pump 110 for pumping and transferring the liquefied gas, and a second pump 120 for pumping the transferred liquefied gas and boosting the pressure to the pressure required by the engine. It is made by two pumps.
  • the first pump 110 is a low-pressure pump for transporting liquefied gas, for example, a centrifugal pump
  • the second pump 120 is a high-pressure pump that compresses the fuel supply pressure required by the engine.
  • the diaphragm pump ( diaphragm pump), and the liquefied gas passing through the first pump and the second pump is heated to a temperature required by the engine in the fuel heater 130 provided at the rear end of the second pump and supplied to the engine.
  • the compressed and heated liquefied gas through the second pump and the fuel heater is supplied to the engine E through the filter 140 that filters out foreign substances in the fuel and the service valve unit SVT.
  • the service valve part while supplying LPG to the engine, when LPG fuel supply is stopped due to engine fuel oil switching, LPG mode stop, trip, etc., each pipe is double-blocked through the valve to relieve pressure in the pipe.
  • An engine receiving such compressed and heated LPG as fuel may be, for example, a ME-LGIP engine of MAN Diesel & Turbo.
  • LPG is supplied to the engine in a high-pressure liquid state of around 54 bar and 35° C. through the compression unit and the fuel heater, and the engine is operated by being hydraulically injected into the nozzle at a pressure of 600 to 700 bar.
  • compressed and heated fuel is supplied to the engine in a liquid state, and unlike the engine to which a compressible fluid having a large volume change according to a change in pressure, that is, gas fuel is supplied, the volume changes even when pressure is applied.
  • a compressible fluid having a large volume change according to a change in pressure that is, gas fuel is supplied
  • sufficient fuel is supplied to respond immediately to changes in engine load and excess LPG is supplied to the engine to prevent cavitation.
  • the remaining LPG consumed as fuel is discharged from the engine through the return line and recirculated.
  • the compressed and heated LPG is recirculated as it is or sent to the fuel supply tank, the vapor), and it may increase the pressure and temperature in the fuel supply tank, which may threaten the safety of the tank and ship.
  • the decompression units 220 and 230 for decompressing the liquefied gas are provided in the return line, so that the liquefied gas discharged from the engine can be recirculated by decompressing the liquefied gas.
  • the compressed liquefied gas is cooled by the Joule-Thomson effect while undergoing adiabatic or isentropic expansion during the decompression process.
  • the compressed liquefied gas recirculated from the engine E through the return line RL1 is reduced in pressure through the decompression unit 220 and cooled, introduced into the separator 210 for gas-liquid separation, and the liquid liquefied gas separated from the separator is It is supplied to the fuel supply line SL between the first pump 110 and the second pump 120 through the liquid line LL and recirculated, and the gas separated from the separator is supplied to the fuel supply tank through the vapor line VL. (DT) is recovered.
  • liquefied gas cooled through decompression is introduced into the separator, and after gas-liquid separation, the liquid liquefied gas is supplied from the fuel supply tank through the first pump to the second pump 120 together with subcooled LPG. Since it is introduced, it is possible to reduce the risk of vapor generation in the suction part of the second pump, and thus a separate device for removing vapor may not be configured.
  • the fuel heater when the temperature of the recirculated liquefied gas is high, the fuel heater must have a cooling function as well as a heating function in order to meet the fuel requirements of the engine.
  • the gas in the decompressed recirculation liquefied gas is recovered to the fuel supply tank, and the mass flow of the high-temperature recirculated liquefied gas sucked into the second pump is reduced, so that fuel at an appropriate temperature can be supplied to the engine without additional cooling. Since the fuel heater only needs to have a heating function, the equipment cost can be reduced and operation is easy.
  • the return line includes a first return line RL1 connected from the engine E to the separator 210 and a separator ( and a second return line RL2 connected to 210 .
  • the decompression unit may include a first decompression device 220 provided in the first return line and a second decompression device 230 provided in the second return line.
  • the first and second pressure reducing devices may include an expander for cooling the compressed liquefied gas by adiabatic or isentropic expansion or an expansion valve such as a Joule-Thomson valve.
  • a return valve unit (RVT) and a filter 240 are provided upstream of the first pressure reducing device in the first return line, and the liquefied gas discharged from the engine is introduced into the first pressure reducing device through the return valve unit and the filter.
  • the filter can filter lubricating oil mixed in the liquefied gas discharged from the engine.
  • the first return line and the first pressure reducing device depressurize the liquefied gas discharged from the engine, and the second return line and the second pressure reducing device reduce the liquefied gas compressed by the second pump to the fuel supply pressure of the engine from upstream of the fuel heater to form a separator. transfer to
  • the LPG remaining in the engine and fuel supply line can also be cooled under reduced pressure and transferred to the separator when the LPG fuel supply is interrupted, such as when the engine is stopped in LPG mode or when tripping.
  • the LPG fuel supply is stopped, it is not necessary to recirculate the LPG from the separator to the fuel supply line, so it can be sent to the fuel supply tank, and for this, a transfer line (not shown) from the separator to the fuel supply tank may be provided.
  • a plurality of pressure sensing units are provided to control the operating pressure.
  • a first pressure sensing unit PC1 that senses the pressure between the second pump and the fuel heater and sends a pressure signal
  • a second pressure sensing unit that senses the pressure between the filter and the first pressure reducing device in the first return line and sends a pressure signal
  • a unit PC2 a third pressure sensing unit PC3 sensing the pressure of the rear end of the first pump, and a fourth pressure sensing unit PC4 sensing the pressure of the separator are provided, respectively.
  • the operating pressure in the system of the present embodiment may be controlled as follows, for example.
  • the operating pressure range of the fuel supply tank is 1 to 8 barg. Assuming that the operating pressure is 4 barg, the differential pressure of the first pump is about 2 bar, and the rear end pressure of the first pump is 6 barg.
  • the operating pressure of the separator 210 is maintained at about 0.5 to 2 bar, more preferably 0.5 to 1 bar higher than the pressure at the rear end of the first pump, so that the liquid recirculation gas separated from the separator is smoothly transferred to the rear end of the first pump.
  • the fourth pressure sensing unit PC4 receives the pressure signal from the third pressure sensing unit PC3, and the fourth pressure sensing unit PC4 sets the set value to the pressure control valve 250 of the vapor line VL.
  • the pressure of the separator is maintained at 6.5 to 7 barg.
  • the liquid separated from the separator is supplied to the front end of the second pump along the liquid line LL, and is pumped from the second pump and pressurized to 54 barg.
  • the separator is provided with a level sensor (LC) that detects the liquid level of the separator, and controls the valve (V1) according to the liquid level of the separator detected by the level sensor to adjust the flow rate of the liquefied gas transferred to the fuel supply line.
  • LC level sensor
  • V1 valve
  • the first return line RL1 returning from the engine controls the first pressure reducing device 220 from the second pressure sensing unit to maintain the pressure upstream of the first pressure reducing device at 22 barg, and the pressure at the rear end of the first pressure reducing device is Maintain at 6.5 to 7 barg equal to the separator pressure.
  • the first pressure sensing unit PC1 detects the pressure and, if it is higher than the set value (54 barg) of the first pressure sensing unit, first of the second pump The pump speed is lowered by adjusting the VFD, and if the pressure is still increased from 54 barg or more to 55 barg, the second pressure reducing device 230 of the second return line is opened to lower the pressure.
  • a discharge pipe DL is provided at the bottom of the separator 210 .
  • Lubricating oil separated from the separator is discharged to a discharge unit including a discharge pipe (DL).
  • 4 schematically shows a configuration of a discharge unit for discharging lubricant oil from a separator in a fuel supply system of a liquefied gas carrier according to the second embodiment.
  • the liquefied gas recovered from the engine may contain, in addition to liquid LPG, gas such as boil-off gas generated through compression and heating for fuel supply and sealing oil introduced from the engine. If it is supplied as a fuel of Also, when lubricating oil flows into the fuel supply tank, there is a risk of crystallization in the tank. In the present embodiment, this can be prevented by separating and discharging the lubricant mixed in the liquefied gas from the separator through the discharge pipe DL provided at the bottom of the separator.
  • LPG is mainly composed of propane (C 3 H 8 ) and butane (C 4 H 10 ). Although there is a difference depending on the ratio of propane and butane, the specific gravity is about 0.5, and the specific gravity of the lubricant is about 0.9. Therefore, in the separator, the gas is separated to the upper part, and the lubricating oil heavier than LPG is layered at the bottom due to the difference in specific gravity. For smoother separation and discharge of lubricating oil, a floating buoyancy body capable of sinking in LNG and floating in lubricating oil may be provided in the separator.
  • the pressure of the separator is maintained at 10 barg or less, the separation and discharge of the lubricant due to the difference in viscosity and specific gravity can be easily achieved.
  • the discharge part includes a discharge pipe (DL) connected from the bottom of the separator 210 and a lubricant discharge tank (SDT) where the discharged lubricant is collected, and a retention pot (retention pot, 300) between the separator and the lubricant discharge tank in the discharge pipe. ) is provided.
  • a magnetic float level gauge 310 is provided in the retention pot to check the liquid level, and between the separator and the retention pot in the discharge pipe, as shown in FIG. 4 , a first discharge valve DV1 And a second discharge valve (DV2) is provided.
  • a third discharge valve (DV3) is provided between the retention pod and the lubricant discharge tank to discharge the separated lubricant to the lubricant discharge tank.
  • the first and second discharge valves (DV1, DV2) are opened, the third discharge valve (DV3) is closed, and the retention time in the pipe is increased by the retention pot provided in the discharge pipe to separate the lubricant efficiency can be increased.
  • a fourth discharge valve that opens and closes the piping branched from the discharge pipe and connected to the lubricant discharge tank in order to relieve the pressure of the discharge pipe between the second discharge valve and the retention pod and to relieve the vacuum state when the lubricant is drained.
  • DV4 is provided.
  • the level gauge 320 for measuring the liquid level is provided in the lubricant discharge tank SDT, and a fifth discharge valve DV5 is provided to discharge the lubricant from the lubricant discharge tank, and the discharged lubricant is in the engine room. It can be sent to the oil tank for reuse or disposal.
  • the ship of this embodiment is provided with a cargo tank (not shown) for storing and transporting liquefied gas as a liquefied gas carrier, and in this embodiment, boil off gas generated from the liquefied gas stored in the cargo tank (not shown) is liquid
  • a cooling line CL is provided so that the liquefied gas re-liquefied by sending it to the re-liquefaction unit RS is connected to the cargo tank (not shown) through the fuel supply tank DT, and the re-liquefaction unit It was configured to cool the fuel supply tank by using the cooling heat of the liquefied gas re-liquefied in the
  • the fuel supply tank supplies fuel to the onboard engine while storing LPG at a pressure of 8 barg or less. Since it is provided on the deck of the ship, the temperature in the tank increases due to external air or gas introduced from the separator.
  • the pressure may rise, in this embodiment by configuring the cooling line CL to re-liquefy the boil-off gas generated from the liquefied gas cargo stored in the cargo tank and then to return to the cargo tank via the fuel supply tank DT, It is possible to cool the fuel supply tank by using the cooling heat of the reliquefied liquefied gas.
  • fuel tanks FT1 and FT2 for supplying liquefied gas to be supplied as fuel of the onboard engine to the fuel supply tank DT disposed on the deck are additionally provided. It is also possible to supply liquefied gas from the fuel supply tank to the fuel supply tank to cool the fuel supply tank by the low-temperature liquefied gas.
  • the temperature and pressure of the fuel supply tank can be adjusted by re-liquefying the boil-off gas generated from the cargo in the cargo tank and cooling the fuel supply tank with the cooling heat of the re-liquefied gas.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

La présente invention concerne un système et un procédé permettant d'alimenter en carburant un transporteur de gaz liquéfié. Le système d'alimentation en carburant pour un transporteur de gaz liquéfié selon la présente invention comprend : une conduite d'alimentation en carburant par laquelle du gaz liquéfié est fourni à partir d'un réservoir d'alimentation en carburant disposé sur le pont d'un navire vers un moteur à l'intérieur du navire ; une partie de compression disposée dans la conduite d'alimentation en carburant et comprimant le gaz liquéfié devant être fourni au moteur à l'intérieur du navire à une pression requise pour le moteur ; une conduite de retour qui fait recirculer le gaz liquéfié qui n'a pas été consommé par le moteur parmi le gaz liquéfié vers l'amont du moteur ; un séparateur disposé dans la conduite de retour et effectuant une séparation gaz-liquide du gaz liquéfié recirculé ; et une partie de décompression disposée en amont du séparateur dans la conduite de retour, le gaz liquéfié recirculé à travers la conduite de retour étant refroidi sous pression réduite dans la partie de décompression et introduit dans le séparateur.
PCT/KR2020/018576 2020-06-18 2020-12-17 Système et procédé permettant d'alimenter en carburant un transporteur de gaz liquéfié WO2021256644A1 (fr)

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CN202080101981.2A CN115697836A (zh) 2020-06-18 2020-12-17 液化气体运输船的燃料供给系统及方法

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KR1020200074179A KR102327410B1 (ko) 2020-06-18 2020-06-18 액화가스 운반선의 연료공급시스템 및 방법
KR10-2020-0074179 2020-06-18
KR10-2020-0118376 2020-09-15
KR1020200118376A KR20220036446A (ko) 2020-09-15 2020-09-15 액화가스 운반선의 연료공급시스템 및 방법

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JPH1019199A (ja) * 1996-07-05 1998-01-23 Mitsubishi Heavy Ind Ltd Ｌｎｇボイルオフガスの再液化方法及びその装置
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