KR20160113535A - Reliquefaction System And Method For Boil Off Gas - Google Patents

Reliquefaction System And Method For Boil Off Gas Download PDF

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KR20160113535A
KR20160113535A KR1020160120835A KR20160120835A KR20160113535A KR 20160113535 A KR20160113535 A KR 20160113535A KR 1020160120835 A KR1020160120835 A KR 1020160120835A KR 20160120835 A KR20160120835 A KR 20160120835A KR 20160113535 A KR20160113535 A KR 20160113535A
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South Korea
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gas
compressor
heat exchanger
compressed
storage tank
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KR1020160120835A
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Korean (ko)
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KR101699329B1 (en
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최진열
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대우조선해양 주식회사
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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 
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0201—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using only internal refrigeration means, i.e. without external refrigeration
    • F25J1/0202—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using only internal refrigeration means, i.e. without external refrigeration in a quasi-closed internal refrigeration loop
    • 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
    • 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
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • 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
    • 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
    • F17C5/00—Methods or apparatus for filling containers with liquefied, solidified, or compressed gases under pressures
    • F17C5/02—Methods or apparatus for filling containers with liquefied, solidified, or compressed gases under pressures for filling with liquefied 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
    • F17C7/00—Methods or apparatus for discharging liquefied, solidified, or compressed gases from pressure vessels, not covered by another subclass
    • F17C7/02—Discharging liquefied gases
    • F17C7/04—Discharging liquefied gases with change of state, e.g. vaporisation
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
    • F25J1/0022—Hydrocarbons, e.g. natural gas
    • F25J1/0025—Boil-off gases "BOG" from storages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/004—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by flash gas recovery
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
    • F25J1/008—Hydrocarbons
    • F25J1/0082—Methane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0201—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using only internal refrigeration means, i.e. without external refrigeration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0228—Coupling of the liquefaction unit to other units or processes, so-called integrated processes
    • F25J1/0229—Integration with a unit for using hydrocarbons, e.g. consuming hydrocarbons as feed stock
    • F25J1/023—Integration with a unit for using hydrocarbons, e.g. consuming hydrocarbons as feed stock for the combustion as fuels, i.e. integration with the fuel gas system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0244—Operation; Control and regulation; Instrumentation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
    • F25J1/0275—Construction and layout of liquefaction equipments, e.g. valves, machines adapted for special use of the liquefaction unit, e.g. portable or transportable devices
    • F25J1/0277—Offshore use, e.g. during shipping
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
    • F25J1/0298—Safety aspects and control of the refrigerant compression system, e.g. anti-surge control
    • 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
    • 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
    • F17C13/12—Arrangements or mounting of devices for preventing or minimising the effect of explosion ; Other safety measures
    • 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
    • F17C2265/00—Effects achieved by gas storage or gas handling
    • F17C2265/03—Treating the boil-off
    • F17C2265/032—Treating the boil-off by recovery
    • 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
    • F17C2265/00—Effects achieved by gas storage or gas handling
    • F17C2265/06—Fluid distribution
    • F17C2265/066—Fluid distribution for feeding engines for propulsion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/60—Methane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/40—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S220/00—Receptacles
    • Y10S220/901—Liquified gas content, cryogenic

Abstract

A boil-off gas reliquefaction system and method are disclosed. The boil-off gas reliquefaction system comprises: a compressor which compresses boil-off gas generated in a storage tank formed in a ship or an offshore structure; a heat exchanger which exchanges the heat of the boil-off gas compressed in the compressor with the boil-off gas to be induced to the compressor; and an expansion unit which adiabatically expands the compressed boil-off gas heat-exchanged in the heat exchanger, wherein the compressor is a multi-stage compressor which repeats compression and intercooling, and wherein the boil-off gas compressed through a part of the multi-stage compressor is induced to the heat exchanger. Therefore, the present invention improves operation stability and reduces maintenance and replacement costs by preventing a pipe conduit from clogging without a separate oil separator.

Description

증발가스 재액화 시스템 및 방법{Reliquefaction System And Method For Boil Off Gas}BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

본 발명은 증발가스 재액화 시스템 및 방법에 관한 것으로, 더욱 상세하게는 저장탱크에서 발생하는 증발가스를 컴프레서로 압축하고 이를 분기하여, 열교환기에서 컴프레서 도입 전의 증발가스와 열교환시킨 후, 팽창 수단으로 단열팽창시켜 증발가스를 재액화하되, 압축 및 중간 냉각이 반복되는 다단 압축기의 컴프레서 중 일부를 거쳐 압축된 증발가스가 열교환기로 도입되는 증발가스 재액화 시스템에 관한 것이다.More particularly, the present invention relates to a system and a method for re-liquefying an evaporation gas, and more particularly, to a system and method for re-liquefying an evaporation gas, The present invention relates to an evaporative gas re-liquefaction system in which evaporated gas compressed through a part of compressors of a multi-stage compressor in which compression and intermediate cooling are repeated while thermally expanding and evaporating the evaporated gas is introduced into a heat exchanger.

액화천연가스(Liquefied Natural Gas, 이하 "LNG"라 함)는 메탄(methane)을 주성분으로 하는 천연가스를 약 -162℃로 냉각해서 액화시킴으로써 얻을 수 있는 무색투명한 액체로서, 천연가스와 비교해 약 1/600 정도의 부피를 갖는다. 따라서, 천연가스 이송 시 LNG로 액화시켜 이송할 경우 매우 효율적으로 이송할 수 있으며, 일 예로 LNG를 해상으로 수송(운반)할 수 있는 LNG 운반선이 사용되고 있다. Liquefied natural gas (hereinafter referred to as "LNG") is a colorless transparent liquid obtained by cooling methane-based natural gas to about -162 ° C. and liquefying it. / 600. ≪ / RTI > Therefore, it is very efficient to transport liquefied LNG when transporting natural gas. For example, an LNG carrier that can transport (transport) LNG is used.

천연가스의 액화온도는 상압 -163℃의 극저온이므로, LNG는 그 온도가 상압 -163℃ 보다 약간만 높아도 쉽게 증발된다. LNG 운반선의 LNG 저장탱크의 경우 단열처리가 되어 있기는 하지만, 외부의 열이 LNG 저장탱크에 지속적으로 전달되므로, LNG 운반선에 의한 LNG 수송과정에서 LNG가 LNG 저장탱크 내에서 지속적으로 자연 기화되어 LNG 저장 탱크 내에 증발가스(Boil-Off Gas, BOG)가 발생한다.Since the liquefaction temperature of natural gas is a cryogenic temperature of -163 ° C at normal pressure, LNG is easily evaporated even if its temperature is slightly higher than the normal pressure of -163 ° C. LNG storage tanks of LNG carriers are heat-treated, but since external heat is continuously transferred to LNG storage tanks, LNG is constantly spontaneously vaporized in LNG storage tanks during LNG transportation by LNG carrier, Boil-off gas (BOG) is generated in the storage tank.

BOG는 일종의 LNG 손실로서 LNG의 수송효율에 있어서 중요한 문제이며, LNG 저장탱크 내에 증발가스가 축적되면 LNG 저장탱크 내의 압력이 과도하게 상승하여 탱크가 파손될 위험이 있으므로, LNG 저장탱크 내에서 발생하는 BOG를 처리하기 위한 다양한 방법이 연구되고 있다.BOG is a kind of LNG loss, which is an important problem in the transport efficiency of LNG. When the evaporation gas accumulates in the LNG storage tank, the pressure in the LNG storage tank is excessively increased, Have been studied.

최근에는 BOG의 처리를 위해, BOG를 재액화하여 저장탱크로 복귀시키는 방법, BOG를 선박의 엔진의 에너지원으로 사용하는 방법 등이 사용되고 있다. 그리고 잉여의 BOG에 대해서는 가스연소유닛(Gas Combustion Unit, GCU)에서 연소시키는 방법을 사용하고 있다.Recently, for the treatment of BOG, BOG is re-liquefied and returned to the storage tank, and BOG is used as energy source of engine of ship. In addition, the surplus BOG is combusted in a gas combustion unit (GCU).

가스연소유닛은 BOG를 달리 활용할 데가 없는 경우 저장탱크의 압력 조절을 위하여 불가피하게 잉여의 BOG를 연소하는 것으로서, BOG가 가지고 있는 화학 에너지를 연소에 의해 낭비하는 결과를 초래한다는 문제가 있다.The gas combustion unit burns surplus BOG inevitably for controlling the pressure of the storage tank when the BOG can not be utilized otherwise, resulting in a waste of the chemical energy possessed by the BOG by combustion.

LNG 운반선의 추진 시스템에서 메인 추진 장치로서 이중 연료 연소(Dual Fuel, DF) 엔진을 적용하는 경우, LNG 저장탱크 내에서 발생하는 증발가스를 DF 엔진의 연료로서 사용하여 증발가스를 처리할 수 있는데, LNG 저장탱크 내에서 발생하는 증발가스의 양이 DF 엔진에서 선박의 추진에 사용되는 연료의 양을 초과하는 경우에, LNG 저장탱크를 보호하기 위해 증발가스를 가스 연소기로 보내어서 소각시키기도 한다.When a dual fuel (DF) engine is applied as the main propulsion unit in the propulsion system of the LNG carriers, the evaporative gas generated in the LNG storage tank can be used as the fuel of the DF engine to process the evaporative gas, If the amount of evaporative gas generated in the LNG storage tank exceeds the amount of fuel used in the propulsion of the ship in the DF engine, the evaporation gas may be sent to a gas burner to incinerate it to protect the LNG storage tank.

출원번호 제10-2010-0116987호Application No. 10-2010-0116987

극저온인 LNG는 온도 등 외부 환경 변화에 매우 민감하며, 선박의 운항중에도 화물창 내에서 지속적으로 자연 기화되기 때문에 상당한 양의 BOG(Boil Off Gas, 증발가스)가 발생한다. 저장 용기 내부에 BOG가 과다하게 되면 이로 인해 용기 내 압력이 상승하면서 용기가 내부 압력을 견딜 수 없어 폭발할 위험이 있으므로, BOG는 배출시켜 액화한 후 다시 저장하거나, 연소시켜 제거하는 방식으로 처리하게 된다. 선박으로 운송할 경우 단열 구조를 갖추더라도, 저장 용기 내에서 발생하는 증발가스(BOG)의 양은 약 0.05 vol%/day에 이르며, 종래 액화천연가스 운반선의 운항시 시간당 4 내지 6 톤(t), 한번 운항시 약 300톤의 액화천연가스가 증발가스화되는 것으로 알려진다.Cryogenic LNG is very sensitive to changes in the external environment such as temperature, and since it is continuously vaporized in the cargo hold during the operation of the ship, a considerable amount of BOG (boil off gas, evaporation gas) is generated. As the BOG becomes excessive in the storage container, the pressure in the container rises and the container can not withstand the internal pressure and there is a danger of explosion. Therefore, the BOG is discharged and liquefied and then stored or burned and removed do. The amount of evaporative gas (BOG) generated in the storage vessel is about 0.05 vol% / day even when the vessel is equipped with a heat insulating structure. The conventional liquefied natural gas carrier carries 4 to 6 tons / It is known that about 300 tons of liquefied natural gas is vaporized and gasified in a single operation.

증발가스의 재액화를 위해서는, 저장탱크 내부의 증발가스를 저장탱크 외부로 배출시켜 냉동 사이클을 포함한 재액화 장치를 통해 재액화시키는 방법이 이용되는데, 이때 증발가스는 초저온으로 냉각된 냉매, 예를 들어 질소, 혼합냉매 등과의 열교환을 통해 재액화된 후 저장탱크로 복귀된다. 이와 같은 냉동 사이클을 통한 재액화 장치는 운전의 복잡성으로 인해 전체 시스템 제어가 복잡하고, 많은 동력이 소모되는 문제가 있었다.In order to re-liquefy the evaporation gas, the evaporation gas in the storage tank is discharged to the outside of the storage tank and re-liquefied through the re-liquefaction device including the refrigeration cycle. At this time, the evaporation gas is cooled by the ultra- Nitrogen, mixed refrigerant, and the like, and then returned to the storage tank. In such a re-liquefying apparatus through a refrigeration cycle, the entire system control is complicated due to the complexity of operation, and there is a problem that a lot of power is consumed.

이처럼 많은 양의 BOG를 액화시키는 데에는 복잡한 재액화 장치와 많은 에너지를 필요로 하며, 연소시켜 제거하는 경우 연료를 사용하지 못하고 버리게 되는 등의 문제로 인해, 저장탱크로부터 발생하는 증발가스를 효율적으로 처리하기 위한 시스템이 필요하다. In order to liquefy such a large amount of BOG, a complicated re-liquefying device and a large amount of energy are required. In the case of burning and removing the fuel, the fuel can not be used and is discarded. A system is required.

본 발명은 이러한 문제를 해결하기 위한 것으로, 선박의 화물창에서 발생하는 증발가스를 효율적으로 재액화시킬 수 있는 시스템을 제공하고자 한다.SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a system capable of efficiently re-liquefying evaporated gas generated in a cargo hold of a ship.

본 발명의 일 측면에 따르면, 선박 또는 해양 구조물에 마련된 저장탱크에서 발생하는 증발가스를 압축하는 컴프레서; According to an aspect of the present invention, there is provided a compressor for compressing evaporative gas generated in a storage tank provided in a ship or an offshore structure;

상기 컴프레서에서 압축된 증발가스가 상기 컴프레서로 도입될 증발가스와 열교환되는 열교환기; 및A heat exchanger in which the evaporated gas compressed in the compressor is heat-exchanged with the evaporated gas to be introduced into the compressor; And

상기 열교환기에서 열교환된 상기 압축된 증발가스가 단열팽창되는 팽창 수단을 포함하되, And expansion means for thermally expanding the compressed evaporated gas heat-exchanged in the heat exchanger,

상기 컴프레서는 압축 및 중간 냉각이 반복되는 다단 압축기이며, 상기 다단 압축기 중 일부를 거쳐 압축된 증발가스가 상기 열교환기로 도입되는 것을 특징으로 하는 증발가스 재액화 시스템이 제공된다.Wherein the compressor is a multi-stage compressor in which compression and intermediate cooling are repeated, and an evaporated gas compressed through a part of the multi-stage compressor is introduced into the heat exchanger.

바람직하게는, 상기 컴프레서의 다단 압축기 중 일부에는 마모방지를 위한 오일이 공급되고, 상기 다단 압축기 중 오일 공급 전의 압축만을 거친 상기 압축된 증발가스가 상기 열교환기로 도입될 수 있다.Preferably, oil for preventing abrasion is supplied to a part of the multi-stage compressor of the compressor, and the compressed evaporated gas, which has been subjected to compression only before oil supply among the multi-stage compressor, may be introduced into the heat exchanger.

바람직하게는 상기 컴프레서는, 상기 증발가스를 압축하는 복수의 압축부와, 상기 복수의 압축부와 교대로 마련되어 상기 압축부에서 압축된 증발가스를 냉각하는 복수의 중간 냉각부를 포함하며, 상기 복수의 압축부 중 일부에는 피스톤의 마모방지를 위한 오일이 공급될 수 있다. Preferably, the compressor includes a plurality of compressors for compressing the evaporation gas, and a plurality of intermediate coolers provided alternately with the plurality of compressors to cool the evaporated gas compressed by the compressors, Some of the compression portions may be supplied with oil for preventing wear of the piston.

바람직하게는, 상기 열교환기는 PCHE(Printed Circuit Heat Exchanger)일 수 있다. Preferably, the heat exchanger may be a Printed Circuit Heat Exchanger (PCHE).

바람직하게는, 상기 팽창 수단을 거쳐 단열팽창된 상기 증발가스를 기액분리하는 기액분리기를 더 포함하여, 상기 기액분리기에서 분리된 액화천연가스는 상기 저장탱크로 회수되고, 분리된 기체는 상기 저장탱크에서 발생한 상기 증발가스와 함께 상기 열교환기로 도입될 수 있다.Preferably, the system further comprises a gas-liquid separator for gas-liquid separating the vaporized gas that has been thermally expanded through the expansion means, wherein the liquefied natural gas separated from the gas-liquid separator is recovered to the storage tank, May be introduced into the heat exchanger together with the evaporated gas generated in the heat exchanger.

바람직하게는, 상기 팽창 수단은 상기 기액분리기의 전단에 마련되는 적어도 하나의 감압밸브 또는 팽창기를 포함하고, 상기 기액분리기의 후단에는 상기 저장탱크로 회수되는 액화천연가스를 감압하는 제1 감압밸브와, 상기 열교환기로 도입되는 기체를 감압하는 제2 감압밸브가 마련될 수 있다. Preferably, the expansion means includes at least one decompression valve or inflator provided at the front end of the gas-liquid separator, and a downstream end of the gas-liquid separator includes a first pressure reducing valve for reducing the pressure of the liquefied natural gas recovered to the storage tank And a second pressure reducing valve for reducing the pressure of the gas introduced into the heat exchanger.

바람직하게는, 상기 컴프레서에서 상기 증발가스는 150 내지 400 bar의 압력으로 압축되고, 상기 컴프레서에서 압축된 상기 증발가스 중 적어도 일부는 상기 선박 또는 해양 구조물의 엔진 연료로 공급될 수 있다.Preferably, in the compressor, the evaporation gas is compressed to a pressure of 150 to 400 bar, and at least a portion of the evaporation gas compressed in the compressor may be supplied to the engine fuel of the vessel or offshore structure.

바람직하게는, 상기 컴프레서에서 압축된 상기 증발가스 중 적어도 일부를 공급받는 주 엔진; 및 상기 컴프레서 중 일부를 거쳐 압축되어 상기 열교환기로 도입되는 상기 압축된 증발가스 중 적어도 일부를 공급받은 부 엔진을 더 포함할 수 있다.Preferably, the main engine is supplied with at least a portion of the evaporated gas compressed in the compressor; And a sub-engine that is supplied with at least a portion of the compressed evaporative gas compressed through a portion of the compressor and introduced into the heat exchanger.

본 발명의 다른 측면에 따르면, 1) 선박 또는 해양 구조물의 저장탱크에서 발생하는 증발가스를 컴프레서로 압축하는 단계; According to another aspect of the present invention, there is provided a method of compressing an evaporative gas, comprising: 1) compressing an evaporative gas generated in a storage tank of a ship or an offshore structure into a compressor;

2) 압축된 증발가스를 분기하고 열교환기로 도입시켜, 상기 저장탱크에서 발생한 압축 전의 증발가스와 열교환시키는 단계; 및2) introducing the compressed evaporated gas into a heat exchanger to heat-exchange the evaporated gas before compression generated in the storage tank; And

3) 열교환된 상기 증발가스를 단열팽창시키고 기액분리하는 단계를 포함하되, 3) subjecting the heat-exchanged evaporated gas to thermal expansion and gas-liquid separation,

상기 컴프레서는 압축 및 중간 냉각이 반복되는 다단 압축기로 상기 다단 압축기 중 일부에는 마모방지를 위한 오일이 공급되고, 상기 다단 압축기 중 오일 공급 전의 압축기만을 거친 상기 압축된 증발가스가 상기 열교환기로 도입되는 것을 특징으로 하는 증발가스의 재액화 방법이 제공된다.Wherein the compressor is a multi-stage compressor in which compression and intermediate cooling are repeated, and oil for preventing wear is supplied to a part of the multi-stage compressor, and the compressed evaporative gas passing through only the compressor before oil supply from the multi-stage compressor is introduced into the heat exchanger A method for re-liquefying a vaporized gas is provided.

본 발명의 증발가스 재액화 시스템은, 저장탱크에서 발생하는 증발가스를 압축하고, 컴프레서로 도입될 증발가스와 열교환시킨 후 단열팽창시켜 재액화하면서, 컴프레서의 마모방지를 위한 오일이 증발가스에 혼입되지 않도록, 복수의 압축부를 포함하는 컴프레서 중 일부만을 거친 증발가스를 열교환기로 도입시켜 재액화하도록 시스템을 구성한다. The evaporation gas re-liquefaction system of the present invention compresses the evaporation gas generated in the storage tank, heat-exchanges the evaporation gas with the evaporation gas to be introduced into the compressor, and thermally expands and re-liquefies the oil. The system is configured to introduce liquefied gas into a heat exchanger through only a part of the compressors including a plurality of compressors to re-liquefy the liquefied gas.

이와 같이 컴프레서 중 일부만을 거친 증발가스를 도입시키므로, 오일 제거를 위한 별도의 분리기를 설치하지 않아도, 이물질에 취약한 PCHE와 같은 열교환기의 오일에 의한 관로 막힘을 방지할 수 있어, 재액화 시스템의 운용 안정성을 높이고 유지보수 및 장비 교체 비용을 절감할 수 있다. 또한, 열교환기로 도입되는 증발가스가 컴프레서 중 일부만 거치게 되므로, 증발가스를 고압으로 압축하기 위한 컴프레서의 전력 소모를 줄일 수 있다. Since the evaporation gas is introduced only through a part of the compressor in this way, it is possible to prevent clogging of the piping by the oil of the heat exchanger such as PCHE, which is vulnerable to foreign matter, without installing a separate separator for removing oil, Increase reliability and reduce maintenance and equipment replacement costs. In addition, since the evaporation gas introduced into the heat exchanger passes through only a part of the compressor, the power consumption of the compressor for compressing the evaporation gas to a high pressure can be reduced.

한편, 본 발명은 저장탱크에서 발생하는 증발가스 자체의 냉열을 이용하여 증발가스를 재액화시킬 수 있는 시스템으로, 별도의 냉매 시스템을 필요로 하지 않으므로, 초기 설치비 부담과 설비 규모를 줄일 수 있고, 유지보수도 편리해진다. Meanwhile, the present invention is a system which can re-liquefy evaporation gas by using the cooling heat of the evaporation gas itself generated in the storage tank, and does not require a separate refrigerant system, thereby reducing the initial installation cost and facility scale, Maintenance is also convenient.

또한, 재액화를 위해 많은 에너지를 소모하는 재액화 장치를 설치하지 않음으로써 재액화를 위한 장치의 구동 비용을 절감하며, 효과적인 재액화를 통해 연소 등으로 낭비되는 천연가스량을 줄일 수 있어 경제성을 높일 수 있다.In addition, by not providing a re-liquefaction device consuming a large amount of energy for re-liquefaction, it is possible to reduce the driving cost of the device for re-liquefaction and reduce the amount of natural gas wasted by combustion etc. through effective re- .

도 1은 본 발명의 일 실시예에 따른 증발가스 재액화 시스템을 개략적으로 도시한다.
도 2는 본 발명의 다른 실시예에 따른 증발가스 재액화 시스템을 개략적으로 도시한다.
도 3은 본 발명에 적용될 수 있는 열교환기의 일 예를 개략적으로 도시한다.
도 4는 본 발명의 실시예들에서의 증발가스 재액화가 이루어지는 개략적인 경로를 도시한 P-H 선도이다.Figure 1 schematically depicts an evaporative gas re-liquefaction system in accordance with one embodiment of the present invention.
2 schematically shows a vaporization gas remelting system according to another embodiment of the present invention.
FIG. 3 schematically shows an example of a heat exchanger applicable to the present invention.
FIG. 4 is a PH diagram showing a schematic route through which evaporative gas re-injection is performed in the embodiments of the present invention. FIG.

본 발명과 본 발명의 동작상의 이점 및 본 발명의 실시에 의하여 달성되는 목적을 충분히 이해하기 위해서는 본 발명의 바람직한 실시 예를 예시하는 첨부 도면 및 첨부 도면에 기재된 내용을 참조하여야만 한다.In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

이하, 첨부된 도면을 참조하여 본 발명의 바람직한 실시 예를 설명함으로써, 본 발명을 상세히 설명한다. 각 도면에 제시된 동일한 참조부호는 동일한 부재를 나타낸다.Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

도 1에는 본 발명의 일 실시예에 따른 해상 구조물에서의 증발가스 처리 시스템의 개략 구성도가 도시되어 있다.FIG. 1 is a schematic block diagram of an evaporative gas treatment system in a marine structure according to an embodiment of the present invention.

도 1에는, 천연가스를 연료로 사용할 수 있는 고압 천연가스 분사 엔진, 즉 ME-GI 엔진을 설치한 LNG 운반선에 본 발명의 증발가스 처리 시스템이 적용된 예가 도시되어 있지만, 본 발명의 후술할 증발가스 처리를 위한 시스템들은 액화가스 저장탱크가 설치된 모든 종류의 해상 구조물, 즉 LNG 운반선, LNG RV와 같은 선박을 비롯하여, LNG FPSO, LNG FSRU와 같은 해상 플랜트에 적용될 수 있다.1 shows an example in which the evaporative gas treatment system of the present invention is applied to a high-pressure natural gas injection engine capable of using natural gas as fuel, that is, an LNG carrier equipped with an ME-GI engine. However, The systems for treatment can be applied to all types of offshore structures equipped with liquefied gas storage tanks, namely LNG carriers, vessels such as LNG RV, marine plants such as LNG FPSO, LNG FSRU.

도 1에 도시된 바와 같이 본 발명의 제1 실시예에 따른 해상 구조물의 증발가스 처리 시스템에 따르면, 액화가스를 저장하는 저장탱크(11)에서 발생되어 배출된 증발가스(NBOG)는, 증발가스 공급라인(L1)을 따라 이송되어 증발가스 압축부(13)에서 압축된 후 고압 천연가스 분사 엔진, 예컨대 ME-GI 엔진에 공급된다. 증발가스는 증발가스 압축부(13)에 의해 대략 150 내지 300 bara 정도의 고압으로 압축된 후 고압 천연가스 분사 엔진, 예컨대 ME-GI 엔진에 연료로서 공급된다.1, the evaporative gas (NBOG) generated and discharged from the storage tank (11) storing the liquefied gas is supplied to the evaporation gas processing system of the offshore structure according to the first embodiment of the present invention, Is fed along the feed line L1, compressed in the evaporative gas compression section 13, and then supplied to the high-pressure natural gas injection engine, for example, the ME-GI engine. The evaporation gas is compressed to a high pressure of about 150 to 300 bara by the evaporation gas compression unit 13 and then supplied as fuel to a high pressure natural gas injection engine such as an ME-GI engine.

저장탱크는 LNG 등의 액화가스를 극저온 상태로 저장할 수 있도록 밀봉 및 단열 방벽을 갖추고 있지만, 외부로부터 전달되는 열을 완벽하게 차단할 수는 없다. 그에 따라 저장탱크(11) 내에서는 액화가스의 증발이 지속적으로 이루어지며, 증발가스의 압력을 적정한 수준으로 유지하기 위해 증발가스 배출라인(L1)을 통하여 저장탱크(11) 내부의 증발가스를 배출시킨다.The storage tank has a sealing and thermal barrier to store liquefied gases such as LNG in cryogenic conditions, but it can not completely block the heat transmitted from the outside. Accordingly, the evaporation of the liquefied gas is continuously performed in the storage tank 11, and the evaporation gas in the storage tank 11 is discharged through the evaporation gas discharge line L1 to maintain the pressure of the evaporation gas at an appropriate level .

저장탱크(11)의 내부에는 필요시 LNG를 저장탱크의 외부로 배출시키기 위해 배출 펌프(12)가 설치된다.A discharge pump (12) is installed in the storage tank (11) to discharge the LNG to the outside of the storage tank, if necessary.

증발가스 압축부(13)는 하나 이상의 증발가스 압축기(14)와, 이 증발가스 압축기(14)에서 압축되면서 온도가 상승한 증발가스를 냉각시키기 위한 하나 이상의 중간 냉각기(15)를 포함할 수 있다. 도 1에서는 5개의 증발가스 압축기(14)와 5개의 중간 냉각기(15)를 포함하는 다단 압축의 증발가스 압축부(13)가 예시되어 있다. 증발가스 압축부(13)는 예를 들어 증발가스를 약 301 bara까지 압축하도록 구성될 수 있다.The evaporative gas compression section 13 may include at least one evaporative gas compressor 14 and at least one intermediate cooler 15 for cooling the evaporated gas whose temperature has increased while being compressed in the evaporative gas compressor 14. In Fig. 1, there is illustrated a multi-stage compressed evaporative gas compression section 13 including five evaporative gas compressors 14 and five intermediate coolers 15. The evaporation gas compression section 13 can be configured, for example, to compress the evaporation gas to about 301 bara.

증발가스 압축부(13)에서 압축된 증발가스는 증발가스 공급라인(L1)을 통하여 고압 천연가스 분사 엔진에 공급되는데, 고압 천연가스 분사 엔진에서 필요로 하는 연료의 필요량에 따라 압축된 증발가스 전부를 고압 천연가스 분사 엔진에 공급할 수도 있다. 또한, 본 발명에 따르면, 저장탱크(11)로부터 배출되어 증발가스 압축부(13)에서 압축된 증발가스를 제1 스트림이라 할 때, 압축된 증발가스의 제1 스트림을 제2 스트림과 제3 스트림으로 나누어, 제2 스트림은 고압 천연가스 분사 엔진에 연료로서 공급하고 제3 스트림은 액화시켜 저장탱크로 복귀시키도록 구성할 수 있다.The compressed gas is supplied to the high-pressure natural gas injection engine through an evaporation gas supply line (L1). The compressed gas is supplied to the high-pressure natural gas injection engine To the high-pressure natural gas injection engine. According to the present invention, when the evaporated gas discharged from the storage tank 11 and compressed by the evaporated gas compression unit 13 is referred to as a first stream, the first stream of the compressed evaporated gas is divided into the second stream and the third stream Stream, the second stream is supplied as fuel to the high pressure natural gas injection engine, and the third stream is liquefied and returned to the storage tank.

이때, 제2 스트립은 증발가스 공급라인(L1)을 통해 고압 천연가스 분사 엔진에 공급되고, 제3 스트림은 증발가스 복귀라인(L3)을 통해 저장탱크(11)로 복귀된다. 압축된 증발가스의 제3 스트림을 액화시킬 수 있도록 증발가스 복귀라인(L3)에는 열교환기(21)가 설치된다. 열교환기(21)에서는 압축된 증발가스의 제3 스트림을 저장탱크(11)로부터 배출된 후 증발가스 압축부(13)로 공급되는 증발가스와 열교환시킨다.At this time, the second strip is supplied to the high-pressure natural gas injection engine through the evaporation gas supply line (L1), and the third stream is returned to the storage tank (11) through the evaporation gas return line (L3). A heat exchanger (21) is installed in the evaporation gas return line (L3) so that the third stream of the compressed evaporation gas can be liquefied. In the heat exchanger (21), the third stream of the compressed evaporated gas is discharged from the storage tank (11), and then heat-exchanged with the evaporated gas supplied to the evaporated gas compression unit (13).

압축되기 전의 증발가스의 제1 스트림의 유량이 제3 스트림의 유량보다 많기 때문에, 압축된 증발가스의 제3 스트림은 압축되기 전의 증발가스의 제1 스트림으로부터 냉열을 공급받아 액화될 수 있다. 이와 같이 열교환기(21)에서는 저장탱크(11)로부터 배출된 직후의 극저온의 증발가스와 증발가스 압축부(13)에서 압축된 고압 상태의 증발가스를 열교환시켜 이 고압 상태의 증발가스를 액화시킨다.Because the flow rate of the first stream of evaporated gas before being compressed is greater than the flow rate of the third stream, the third stream of compressed evaporated gas may be liquefied by receiving cold heat from the first stream of evaporated gas before being compressed. As described above, in the heat exchanger 21, the extremely low-temperature evaporation gas immediately after being discharged from the storage tank 11 is exchanged with the high-pressure evaporation gas compressed by the evaporation gas compression unit 13 to liquefy the evaporation gas at the high pressure state .

열교환기(21)에서 액화된 증발가스(LBOG)는 팽창밸브(22)를 통과하면서 감압되어 기액 혼합상태로 기액분리기(23)에 공급된다. 팽창밸브(22)를 통과하면서 LBOG는 대략 상압으로 감압될 수 있다. 액화된 증발가스는 기액분리기(23)에서 기체와 액체 성분이 분리되어, 액체성분, 즉 LNG는 증발가스 복귀라인(L3)을 통해 저장탱크(11)로 이송되고, 기체성분, 즉 증발가스는 증발가스 재순환라인(L5)을 통해 저장탱크(11)로부터 배출되어 증발가스 압축부(13)로 공급되는 증발가스에 합류된다. 더욱 상세하게는, 증발가스 재순환라인(L5)은 기액분리기(23)의 상단으로부터 연장되어 증발가스 공급라인(L1)에서 열교환기(21)보다 상류측에 연결된다.The evaporated gas LBOG liquefied in the heat exchanger 21 is reduced in pressure while passing through the expansion valve 22 and supplied to the gas-liquid separator 23 in a vapor-liquid mixed state. The LBOG can be decompressed to approximately atmospheric pressure while passing through the expansion valve 22. The liquefied evaporated gas is separated from the gas and liquid components in the gas-liquid separator 23, and the liquid component, that is, the LNG is transferred to the storage tank 11 through the evaporated gas return line L3, and the gas component, And is merged into the evaporation gas discharged from the storage tank 11 through the evaporation gas recycle line L5 and supplied to the evaporation gas compression unit 13. More specifically, the evaporation gas recycle line L5 extends from the upper end of the gas-liquid separator 23 and is connected to the evaporation gas supply line L1 on the upstream side of the heat exchanger 21.

위에서는 설명의 편의상 열교환기(21)가 증발가스 복귀라인(L3)에 설치된 것으로 설명하였으나, 실제로 열교환기(21)에서는 증발가스 공급라인(L1)을 통해 이송되고 있는 증발가스의 제1 스트림과 증발가스 복귀라인(L3)을 통해 이송되고 있는 증발가스의 제3 스트림 사이에 열교환이 이루어지고 있으므로, 열교환기(21)는 증발가스 공급라인(L1)에 설치된 것이기도 하다.In the above description, the heat exchanger 21 is provided in the evaporation gas return line L3, but in the heat exchanger 21, the first stream of the evaporation gas being fed through the evaporation gas supply line L1 The heat exchanger 21 is installed in the evaporation gas supply line L1 since heat exchange is performed between the third stream of the evaporation gas being transferred through the evaporation gas return line L3.

증발가스 재순환라인(L5)에는 또 다른 팽창밸브(24)가 더 설치될 수 있으며, 그에 따라 기액분리기(23)로부터 배출된 기체 성분은 팽창밸브(24)를 통과하면서 감압될 수 있다. 또한 열교환기(21)에서 액화된 후 기액분리기(23)로 공급되는 증발가스의 제3 스트림과 기액분리기(23)에서 분리되어 증발가스 재순환라인(L5)을 통해 이송되는 기체 성분을 열교환시켜 제3 스트림을 더욱 냉각시킬 수 있도록 증발가스 재순환라인(L5)에는 냉각기(25)가 설치된다. 즉, 냉각기(25)에서는 고압 액체 상태의 증발가스를, 저압 극저온 기체 상태의 천연가스와 열교환으로 추가 냉각시킨다.The evaporation gas recirculation line L5 may be further provided with another expansion valve 24 so that the gas component discharged from the gas-liquid separator 23 can be decompressed while passing through the expansion valve 24. The third stream of the evaporated gas supplied to the gas-liquid separator 23 after being liquefied in the heat exchanger 21 is heat-exchanged with the gas component separated by the gas-liquid separator 23 and conveyed through the evaporation gas recycle line L5, The evaporator gas recycle line (L5) is equipped with a cooler (25) to further cool the stream. That is, in the cooler 25, the evaporation gas in the high-pressure liquid state is further cooled by heat exchange with the natural gas in the low-pressure cryogenic gaseous state.

여기에서, 설명의 편의상 냉각기(25)가 증발가스 재순환라인(L5)에 설치된 것으로 설명하였으나, 실제로 냉각기(25)에서는 증발가스 복귀라인(L3)을 통해 이송되고 있는 증발가스의 제3 스트림과 증발가스 재순환라인(L5)을 통해 이송되고 있는 기체 성분 사이에 열교환이 이루어지고 있으므로, 냉각기(25)는 증발가스 복귀라인(L3)에 설치된 것이기도 하다.Although the cooler 25 has been described as being installed in the evaporative gas recirculation line L5 for convenience of explanation, in the cooler 25 in reality, the third stream of the evaporative gas being fed through the evaporative gas return line L3, The cooler 25 is provided in the evaporation gas return line L3 since heat exchange is performed between the gas components being transferred through the gas recirculation line L5.

한편, 저장탱크(11)에서 발생하는 증발가스의 양이 고압 천연가스 분사 엔진에서 요구하는 연료량보다 많아 잉여의 증발가스가 발생할 것으로 예상되는 경우에는, 증발가스 압축부(13)에서 압축된 혹은 단계적으로 압축되고 있는 도중의 증발가스를, 증발가스 분기라인(L7, L8)을 통하여 분기시켜 증발가스 소비수단에서 사용한다. 증발가스 소비수단으로서는 ME-GI 엔진에 비해 상대적으로 낮은 압력의 천연가스를 연료로서 사용할 수 있는 GCU, DF Generator, 가스 터빈, DFDE 등이 사용될 수 있다.If the amount of evaporative gas generated in the storage tank 11 is higher than the amount of fuel required by the high-pressure natural gas injection engine and excess evaporative gas is expected to be generated, the compressed or stepped Is branched through the evaporation gas branch lines (L7, L8) and used in the evaporation gas consumption means. GCU, DF Generator, Gas Turbine, DFDE, etc., which can use natural gas relatively low pressure compared to ME-GI engine, can be used as evaporative gas consumption means.

도 2에는 본 발명의 다른 실시예에 따른 증발가스의 재액화 시스템을 개략적으로 도시하였다. FIG. 2 schematically shows a re-liquefaction system for a vaporized gas according to another embodiment of the present invention.

도 2에 도시된 바와 같이, 본 실시예의 증발가스 재액화 시스템은, 선박 또는 해양 구조물에 마련된 저장탱크(T)에서 발생하는 증발가스를 압축하는 컴프레서(100)와, 컴프레서(100)에서 압축된 증발가스가 컴프레서로 도입될 증발가스와 열교환되는 열교환기(200)와, 열교환기에서 열교환된 압축된 증발가스가 단열팽창되는 팽창 수단(400, 410)을 포함하되, 컴프레서는 압축 및 중간 냉각이 반복되는 다단 압축기이며, 다단 압축기 중 일부를 거쳐 압축된 증발가스가 열교환기로 도입되는 것이 특징이다.2, the evaporation gas re-liquefaction system of the present embodiment includes a compressor 100 for compressing evaporative gas generated in a storage tank T provided in a ship or an offshore structure, (400, 410) in which the evaporated gas is heat-exchanged with the evaporated gas to be introduced into the compressor, and the compressed evaporated gas heat-exchanged in the heat exchanger is subjected to a thermal expansion, And is characterized in that the evaporated gas compressed through a part of the multi-stage compressor is introduced into the heat exchanger.

본 실시예의 컴프레서(100)는, 증발가스를 압축하는 복수의 압축부(110)와, 복수의 압축부와 교대로 마련되어 압축부에서 압축된 증발가스를 냉각하는 복수의 중간 냉각부(120)를 포함하는 다단 압축기이며, 저장탱크(T)에서 발생하는 증발가스를 150 내지 400 bar로 압축할 수 있다. 압축부 중 일부는 도 2에 도시된 첫 번째 압축부와 같이 하나 이상의 실린더, 예를 들어 두 개의 실린더(111)가 직렬 연결된 구성으로 이루어질 수도 있다. The compressor 100 of the present embodiment includes a plurality of compressing units 110 for compressing the evaporation gas and a plurality of intermediate cooling units 120 alternately provided with the plurality of compressing units for cooling the evaporation gas compressed by the compressing unit And is capable of compressing the evaporation gas generated in the storage tank T to 150 to 400 bar. Some of the compressing units may have a configuration in which one or more cylinders, for example, two cylinders 111 are connected in series, like the first compressing unit shown in FIG.

이와 같은 복수의 압축부(110) 중 일부에는 피스톤의 마모방지를 위한 오일이 공급되는데, 이러한 압축부 전부를 거쳐 압축된 증발가스에는 컴프레서(100)로 공급되었던 마모방지용 오일, 즉 윤활유가 혼입될 수 있으므로, 본 실시예에서는 다단 압축기 중 오일 공급 전의 압축부 만을 거쳐 압축된 증발가스가 열교환기(200)로 도입되도록 유로를 분기한다. Oil for preventing abrasion of the piston is supplied to a part of the plurality of compressing units 110. To the evaporated gas compressed through all of the compressing units, a lubricating oil, i.e., lubricating oil supplied to the compressor 100 is mixed Therefore, in this embodiment, the flow path is branched so that the evaporated gas compressed through only the compressed portion before the oil supply from the multi-stage compressor is introduced into the heat exchanger 200.

이러한 컴프레서는 총 5개의 실린더를 포함하며, 전단 3개의 실린더는 무급유 윤활(oil-free) 방식으로 동작하고 후단 2개의 실린더는 급유 윤활(oil-lubricated) 방식으로 동작할 수 있다. 이와 같은 컴프레서(100)로는, 부카르트(Burckhardt) 사의 컴프레서를 예로 들 수 있다. 이는 후단으로 갈수록 실린더의 피스톤 링이 마모될 위험이 크기 때문에, 피스톤 링의 마모 방지를 위해 후단의 실린더에 윤활유(Lubrication oil)를 공급하는 것이다. 따라서, 이러한 컴프레서를 사용하여, 4단 이상에서 압축된 증발가스를 분기시키는 경우, 압축된 증발가스는 윤활유를 포함할 수 있다. 따라서 압축된 증발가스에 포함된 윤활유도 열교환기로 도입될 수 있게 된다. These compressors include a total of five cylinders, the front three cylinders operating in an oil-free manner, and the two cylinders in the downstream operating in an oil-lubricated manner. As such a compressor 100, a compressor of Burkhardt Co., Ltd. is exemplified. This is because there is a great risk that the piston ring of the cylinder will wear down toward the rear end, so that lubrication oil is supplied to the cylinder at the rear end to prevent wear of the piston ring. Thus, when using such a compressor, the compressed evaporated gas may include lubricating oil when it is branched in four or more stages. Therefore, the lubricating oil contained in the compressed evaporated gas can be introduced into the heat exchanger.

이때 본 실시예에서의 열교환기(200)는 바람직하게는, PCHE(Printed Circuit Heat Exchanger)이다. At this time, the heat exchanger 200 in this embodiment is preferably a PCHE (Printed Circuit Heat Exchanger).

PCHE 열교환기의 개략적인 구조는 도 3에 도시되는데, 도시된 바와 같이 PCHE 열교환기는 열교환될 유체가 서로 다른 방향에서 열교환기로 유입되어(S1, S2) 이를 통과하면서 열교환이 이루어진다. 이와 같은 PCHE 열교환기는 열교환가능한 온도 범위가 -200 내지 900℃ 정도로 매우 넓고, 열교환기 단위 부피당 열전이 면적이 넓어 높은 열 전달률을 나타내며, 기체와 액체, 이상(two-phase) 흐름 등의 여러 유체에 이용할 수 있는 장점이 있다. The schematic structure of the PCHE heat exchanger is shown in FIG. 3, in which the PCHE heat exchanger is heat exchanged while the fluid to be heat-exchanged flows into the heat exchanger from different directions (S1, S2). Such a PCHE heat exchanger has a very wide heat exchangeable temperature range of about -200 to 900 ° C. and a large heat transfer area per unit volume of the heat exchanger, exhibits a high heat transfer rate and can be applied to various fluids such as gas and liquid and two- There are advantages to be able to use.

반면에 열교환기 내부의 circuit이 매우 작아 이물질이 유입되면 관로가 막히는 문제가 있을 수 있다. 따라서, 압축된 증발가스에 포함된 컴프레서 마모방지용 오일, 즉 윤활유는 PCHE 열교환기의 관로 막힘을 초래할 수 있으며, 이로 인해 재액화 시스템의 가동이 중단될 위험이 있다. 특히 열교환기(200)에서 열교환을 통해 압축된 증발가스는 냉각되므로, 증발가스에 포함된 윤활유도 냉각에 의해 점도가 높아지고 이로 인한 관로 막힘의 위험이 매우 크다. 본 실시예는 이러한 문제의 해결을 위해 컴프레서(100) 중 마모방지용 오일이 공급되지 않는 전단의 실린더 압축부와 중간 냉각부 만을 거쳐 압축된 증발가스를 컴프레서 중간에서 분기하여 열교환기로 도입시키게 된다. 부카르트(Burckhardt) 사의 컴프레서를 예로 들면 5개의 실린더 중 1개 내지 3개의 실린더만을 거친 증발가스를 분기할 수 있다. On the other hand, since the circuit inside the heat exchanger is very small, there may be a problem that the pipeline is clogged when foreign matter is introduced. Therefore, the oil for preventing compressor wear, that is, the lubricating oil contained in the compressed evaporated gas, may cause pipe clogging of the PCHE heat exchanger, which may cause the operation of the re-liquefaction system to be interrupted. Particularly, since the evaporated gas compressed through the heat exchange in the heat exchanger 200 is cooled, the viscosity of the lubricating oil contained in the evaporated gas increases due to the cooling, and there is a great risk of clogging the pipe. In this embodiment, in order to solve such a problem, the evaporation gas compressed through only the cylinder compression section and the intermediate cooling section at the front end of the compressor 100, which is not supplied with the anti-wear oil, is branched from the middle of the compressor and introduced into the heat exchanger. In the case of a compressor of Burckhardt Co., for example, it is possible to divide the evaporative gas through only one to three cylinders out of five cylinders.

이와 같이 윤활유가 공급되지 않는 다단 압축기 일부만을 거쳐 증발가스를 열교환기(200)로 도입시키므로, 컴프레서의 하류측에 컴프레서로부터 열교환기로 도입되는 압축된 증발가스에 포함된 오일을 제거하기 위한 오일 분리기를 별도로 설치하지 않고도 열교환기의 관로 막힘을 방지할 수 있다. Since the evaporated gas is introduced into the heat exchanger 200 through only a part of the multi-stage compressor in which no lubricant is supplied, an oil separator for removing the oil contained in the compressed evaporative gas introduced into the heat exchanger from the compressor, It is possible to prevent clogging of the piping of the heat exchanger without installing it separately.

또한, 컴프레서 일부만을 거쳐 압축시키므로 컴프레서(100)의 전력 소모를 줄일 수 있는 장점도 있다. In addition, since only a part of the compressor is compressed, there is an advantage that the power consumption of the compressor 100 can be reduced.

본 실시예에서는 컴프레서에서 증발가스를 150 내지 400 bar의 압력으로 압축시키고, 압축된 증발가스 중 적어도 일부는 선박 또는 해양 구조물의 엔진 연료로 공급되는데, 이와 같이 증발가스를 연료로 공급받는 엔진은 주 엔진(E1)과 부 엔진(E2)이 구성된다. In this embodiment, the compressor compresses the evaporation gas to a pressure of 150 to 400 bar, and at least a portion of the compressed evaporation gas is supplied to the engine or fuel of the ship or an offshore structure. The engine E1 and the sub engine E2 are constituted.

바람직하게는, 주 엔진(E1)은 컴프레서의 다단 압축기 전부를 거쳐 압축된 고압의 증발가스를 공급받는 MEGI 엔진이고, 부 엔진(E2)은 다단 압축기 일부를 거쳐 압축된 증발가스를 분기시켜 공급받는 DFDG(Dual Fuel Diesel Generator)등의 DF 엔진이다. DF 엔진으로 공급되는 분기 라인(L2b)은 컴프레서 중간에서 분기되어 열교환기로 도입되는 라인(L2a)으로부터 분기될 수도 있다.Preferably, the main engine E1 is a MEGI engine that is supplied with a high-pressure evaporation gas compressed through all of the multi-stage compressors of the compressor, and the sub-engine E2 is a multi- And DFDG (Dual Fuel Diesel Generator). The branch line L2b supplied to the DF engine may branch off from the line L2a branched from the middle of the compressor and introduced into the heat exchanger.

상술한 MEGI 엔진에서 요구하는 150 ∼ 400 bara(절대압력) 정도의 고압까지 기체(BOG)를 압축하기 위한 압축기는 상당히 고가이고 부피 역시 많이 차지하고 전력 소모도 매우 크다. 예를 들어, 다단으로 구성된 5단 압축기를 구동시켜 ME-GI 엔진에 연료를 공급하기 위해서는 2MW의 전력이 소비되는 반면, 2단까지만 사용하고 나머지 3단을 공회전시킬 경우 요구되는 전력은 600kW이다. The compressor for compressing the gas (BOG) to a high pressure of 150 to 400 bara (absolute pressure) required by the MEGI engine described above is considerably expensive, has a large volume, and consumes a large amount of power. For example, 2 MW of power is consumed to fuel the ME-GI engine by driving a 5-stage compressor composed of multi-stages, while 600 kW is required when only the second stage is used and the remaining three stages are idling.

따라서, 증발가스를 150 내지 400 bara 까지 압축시키지 않고 다단 압축기 일부만을 거쳐 재액화하는 경우 컴프레서(100)의 소모 전력을 크게 줄일 수 있다. 이러한 경우, MEGI 엔진과 같은 주 엔진(E1)은 증발가스 대신, 저장탱크에 저장된 액화천연가스를 펌프(미도시)와 기화기(미도시)를 거쳐 공급받도록 시스템을 구성할 수 있다. Accordingly, when the evaporator is re-liquefied through only a part of the multi-stage compressor without compressing the evaporation gas to 150 to 400 bara, the consumption power of the compressor 100 can be greatly reduced. In this case, the main engine E1, such as the MEGI engine, can configure the system to receive the liquefied natural gas stored in the storage tank via a pump (not shown) and a vaporizer (not shown) instead of the evaporated gas.

그리하여 밸러스트 상태와 같이 BOG 발생량이 MEGI 엔진에서의 연료 필요량보다 적은 경우에는 BOG는 DF 엔진과 재액화를 통해 처리하고, MEGI 엔진은 펌프를 통해 LNG를 연료로서 공급하는 것이 에너지 효율 측면에서 유리하다.Thus, when the BOG generation amount is less than the fuel requirement amount in the MEGI engine, such as the ballast condition, the BOG is processed through the DF engine and the liquefaction process, and the MEGI engine is advantageous in terms of energy efficiency to supply the LNG as fuel through the pump.

또한 본 발명의 실시예들은 증발가스를 컴프레서(100)로 압축하여 별도의 냉매 시스템 없이 저장탱크(T)로부터 공급되는 증발가스 저온을 이용하여 재액화하고 회수함으로써 GCU에서 연소 등으로 증발가스가 낭비되는 것을 막을 수 있다. 또한, 컴프레서(100)로 기체를 압축하는 경우, 일정량의 기체 유량까지는 컴프레서(100)의 전력 소모가 일정하게 유지되다가 이후 전력 소모가 커지게 되는데, 전력 소모가 일정하게 유지되는 수준까지 증발가스를 압축하여 연료로 보내거나 재액화하는 경우 추가적인 전력 소모 없이 효과적으로 증발가스를 처리할 수 있다. In the embodiments of the present invention, the evaporation gas is compressed by the compressor 100 and re-liquefied and recovered by using the low temperature of the evaporation gas supplied from the storage tank T without a separate refrigerant system. As a result, . In addition, when the gas is compressed by the compressor 100, the power consumption of the compressor 100 is kept constant until a certain amount of the gas flow rate, and then the power consumption is increased. However, If compressed and sent to fuel or liquefied, the evaporative gas can be effectively treated without additional power consumption.

한편, 컴프레서(100)에서의 압축을 거치면서 증발가스는 온도가 높아지는데, 이를 저장탱크(T)에서 발생하여 컴프레서(100)로 도입될 증발가스와 열교환기(200)에서 열교환시킴으로써, 압축된 증발가스에 저장탱크로부터 공급된(L1) 증발가스의 냉열을 전달한다. On the other hand, the temperature of the evaporation gas increases as the compressor 100 compresses it. By exchanging heat between the evaporation gas generated in the storage tank T and the refrigerant to be introduced into the compressor 100 in the heat exchanger 200, (L1) supplied from the storage tank to the evaporation gas.

본 실시예의 도 2에서는 1개의 열교환기(200)가 마련된 시스템을 도시하였지만, 열교환기를 복수로 마련하여, 열교환기 일부에서 관로 막힘이나 다른 고장, 열교환기 교체 등의 유지보수가 이루어질 때에도 나머지 열교환기를 통해 증발가스의 열교환이 이루어질 수 있어 중단 없이 증발가스를 재액화할 수 있도록 시스템을 구성할 수도 있다. Although a system having one heat exchanger 200 is shown in FIG. 2 of the present embodiment, a plurality of heat exchangers may be provided so that the remaining heat exchangers are installed in a part of the heat exchanger even when maintenance is performed such as clogging of pipes, Heat exchange of the evaporation gas may be performed through the evaporator, so that the system can be configured to re-liquefy the evaporation gas without interruption.

본 실시예에서 열교환기(200)를 거친 증발가스는 유로(L3)를 따라 팽창 수단, 예를 들어 감압 밸브(400, 410)로 도입되고, 감압 밸브(40, 410)를 통과하며 단열팽창된 증발가스는 기액분리기(500)로 도입되어 기액분리된다. In the present embodiment, the evaporated gas passing through the heat exchanger 200 is introduced into the expansion means, for example, the pressure reducing valves 400 and 410 along the flow path L3, passes through the pressure reducing valves 40 and 410, The evaporated gas is introduced into the gas-liquid separator 500 to be subjected to gas-liquid separation.

팽창기 또는 감압 밸브 등의 팽창 수단은 도 2에 도시된 바와 같이 복수로(400, 410) 마련될 수 있고, 기액분리기에는 레벨 센서(510)가 마련될 수 있다.Expansion means such as an expander or a pressure reducing valve may be provided in a plurality of passages 400 and 410 as shown in FIG. 2, and a level sensor 510 may be provided in the gas-liquid separator.

감압 후 기액분리기(500)에서 분리된 액화천연가스는 저장탱크(T)로 회수되고(L4), 분리된 기체는 저장탱크(T)에서 발생한 증발가스의 흐름에 합류되어(L5), 함께 열교환기(200)로 도입될 수 있다. The liquefied natural gas separated in the gas-liquid separator 500 after the decompression is recovered to the storage tank T4 and the separated gas is joined to the flow of the evaporative gas generated in the storage tank T5, Can be introduced into the vessel 200.

감압 밸브(400, 410)는 줄-톰슨 밸브가 사용될 수 있으며, 감압 밸브를 대신하여 팽창기(expander)를 비롯한 다른 감압 장치가 사용될 수도 있다. 냉각된 증발가스는 감압 밸브 등의 감압 장치를 통해 단열팽창되면서 압력이 낮아진다. The decompression valves 400 and 410 may be Row-Thompson valves, and other decompression devices, including an expander, may be used in place of the decompression valves. The cooled evaporated gas is mono-expanded through a decompression device such as a pressure reducing valve, and the pressure is lowered.

이와 같이 저장탱크(T)에서 발생한 증발가스를 압축, 냉각 및 단열팽창 과정을 거치면서 재액화되어, 기액분리기(500)를 통해 액화천연가스가 분리되어 저장탱크(T)로 회수된다. The evaporated gas generated in the storage tank T is re-liquefied under compression, cooling, and thermal expansion processes, and the liquefied natural gas is separated through the gas-liquid separator 500 and recovered into the storage tank T.

기액분리기의 후단에는 저장탱크로 회수되는 액화천연가스를 추가로 감압하는 제1 감압밸브(420)와, 열교환기로 도입되는 기체를 추가로 감압하는 제2 감압밸브(430)가 추가로 마련될 수 있다.Liquid separator may further include a first pressure reducing valve 420 for further reducing the pressure of the liquefied natural gas recovered to the storage tank and a second pressure reducing valve 430 for further reducing the pressure of the gas introduced into the heat exchanger have.

한편, 컴프레서(100) 전부를 거쳐 150 내지 400 bar의 압력으로 압축된 증발가스는 선박 또는 해양 구조물의 엔진 연료로 공급될 수 있는데, 특히 이때의 주 엔진은 전술한 바와 같이 고압가스를 연료로 하는 고압가스 분사엔진, 바람직하게는 ME-GI 엔진(E1)이다. 전술한 실시예에서와 같이 ME-GI 엔진 외에, ME-GI 엔진보다 낮은 압력의 연료를 공급받는 DFDE나 DF generator 등(E2)을 추가로 구성하여 컴프레서 중간에서 압축된 가스를 분기하여(L2b) 이들의 연료로 공급할 수도 있다.On the other hand, the evaporated gas compressed at a pressure of 150 to 400 bar through the entire compressor 100 can be supplied as engine fuel for a ship or an offshore structure. In particular, the main engine at this time is a high- Pressure gas injection engine, preferably an ME-GI engine (E1). In addition to the ME-GI engine, a DFDE or DF generator (E2), such as a DFDE or a DF generator (E2), which receives fuel at a pressure lower than that of the ME-GI engine, is additionally provided to divide the compressed gas in the middle of the compressor They can also be supplied as fuel.

이와 같이 다단 압축을 통한 본 실시예의 재액화 경로는, 도 4의 P-H 선도에서 표시된 경로로 나타낼 수 있다. (a)는 5단 압축을 거쳐 증발가스를 재액화하는 경우이고, (b)는 5단 중 3단의 압축만을 거쳐 증발가스를 재액화하는 경우이다.The re-liquefying path of this embodiment through multi-stage compression in this way can be represented by the path shown in the P-H diagram of Fig. (a) shows the case where the evaporation gas is re-liquefied through the five-stage compression, and (b) shows the case where the evaporation gas is re-liquefied only through the three-stage compression of the five stages.

이상에서 살펴본 바와 같이 본 실시예에서는, 1) 선박 또는 해양 구조물의 저장탱크에서 발생하는 증발가스를 컴프레서로 압축하는 단계; 2) 압축된 증발가스를 분기하고 열교환기로 도입시켜, 저장탱크에서 발생한 압축 전의 증발가스와 열교환시키는 단계; 및 3) 열교환된 증발가스를 단열팽창시키고 기액분리하는 단계를 포함하되, 컴프레서는 압축 및 중간 냉각이 반복되는 다단 압축기로, 다단 압축기 중 일부에는 마모방지를 위한 오일이 공급되고, 다단 압축기 중 오일 공급 전의 압축기만을 거쳐 압축된 증발가스를 열교환기로 도입시킴으로써, 컴프레서의 전력 소모를 줄이고 열교환기의 관로 막힘을 방지할 수 있다. As described above, in this embodiment, 1) compressing evaporative gas generated from a storage tank of a ship or an offshore structure by a compressor; 2) introducing the compressed evaporated gas into a heat exchanger to heat-exchange the evaporated gas before compression generated in the storage tank; And 3) a step of thermally expanding and evaporating the heat-exchanged evaporated gas to separate the gas and liquid, wherein the compressor is a multi-stage compressor in which the compression and the intermediate cooling are repeated, the oil for preventing wear is supplied to a part of the multi- It is possible to reduce the power consumption of the compressor and to prevent clogging of the piping of the heat exchanger by introducing the compressed evaporated gas through only the compressor before the supply to the heat exchanger.

이와 같이 본 발명은 기재된 실시 예에 한정되는 것이 아니고, 본 발명의 사상 및 범위를 벗어나지 않고 다양하게 수정 및 변형할 수 있음은 이 기술의 분야에서 통상의 지식을 가진 자에게 자명하다. 따라서 그러한 수정 예 또는 변형 예들은 본 발명의 특허청구범위에 속한다 하여야 할 것이다.It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

100: 컴프레서
110: 압축부
120: 중간 냉각부
200: 열교환기
300: 오일 분리기
400, 410, 420, 430: 감압 밸브
500: 기액분리기
T: 저장탱크
E1, E2: 엔진100: Compressor
110:
120: Intermediate cooling section
200: heat exchanger
300: Oil separator
400, 410, 420, 430: Decompression valve
500: gas-liquid separator
T: Storage tank
E1, E2: engine

Claims (9)

선박 또는 해양 구조물에 마련된 저장탱크에서 발생하는 증발가스를 압축하는 컴프레서;
상기 컴프레서에서 압축된 증발가스가 상기 컴프레서로 도입될 증발가스와 열교환되는 열교환기; 및
상기 열교환기에서 열교환된 상기 압축된 증발가스가 단열팽창되는 팽창 수단;을 포함하고,
상기 컴프레서는 압축 및 중간 냉각이 반복되는 다단 압축기이며, 상기 다단 압축기 중 일부를 거쳐 압축된 증발가스가 상기 열교환기로 도입되며,
상기 컴프레서의 다단 압축기 중 일부에는 마모방지를 위한 오일이 공급되고, 상기 다단 압축기 중 오일 공급 전의 압축만을 거친 상기 압축된 증발가스가 상기 열교환기로 도입되는 것을 특징으로 하는, 증발가스 재액화 시스템.A compressor for compressing evaporative gas generated in a storage tank provided in a ship or an offshore structure;
A heat exchanger in which the evaporated gas compressed in the compressor is heat-exchanged with the evaporated gas to be introduced into the compressor; And
And expansion means in which the compressed evaporated gas heat-exchanged in the heat exchanger is thermally expanded,
Wherein the compressor is a multi-stage compressor in which compression and intermediate cooling are repeated, evaporated gas compressed through a part of the multi-stage compressor is introduced into the heat exchanger,
Wherein a portion of the multi-stage compressors of the compressor is supplied with oil for preventing wear, and the compressed evaporated gas, which has been subjected to compression only before oil supply, of the multi-stage compressor is introduced into the heat exchanger. 제 1항에 있어서, 상기 컴프레서는,
상기 증발가스를 압축하는 복수의 압축부; 및
상기 복수의 압축부와 교대로 마련되어 상기 압축부에서 압축된 증발가스를 냉각하는 복수의 중간 냉각부를 포함하며,
상기 복수의 압축부 중 일부에는 피스톤의 마모방지를 위한 오일이 공급되는 것을 특징으로 하는 증발가스 재액화 시스템. The compressor according to claim 1,
A plurality of compressing units for compressing the evaporating gas; And
And a plurality of intermediate coolers alternately provided with the plurality of compressors and cooling the evaporated gas compressed by the compressors,
Wherein a part of the plurality of compression units is supplied with oil for preventing wear of the piston. 제 1항에 있어서,
상기 열교환기는 PCHE(Printed Circuit Heat Exchanger)인 것을 특징으로 하는 증발가스 재액화 시스템. The method according to claim 1,
Wherein the heat exchanger is a PCHE (Printed Circuit Heat Exchanger). 제 1항에 있어서,
상기 팽창 수단을 거쳐 단열팽창된 상기 증발가스를 기액분리하는 기액분리기를 더 포함하여,
상기 기액분리기에서 분리된 액화천연가스는 상기 저장탱크로 회수되는 것을 특징으로 하는 증발가스 재액화 시스템. The method according to claim 1,
And a gas-liquid separator for separating the vaporized gas that has been thermally expanded through the expansion means by gas-liquid separation,
And the liquefied natural gas separated from the gas-liquid separator is recovered to the storage tank. 제 4항에 있어서,
상기 기액분리기에서 분리된 기체는 상기 저장탱크에서 발생한 상기 증발가스와 함께 상기 열교환기로 도입되는 것을 특징으로 하는 증발가스 재액화 시스템.5. The method of claim 4,
Wherein the gas separated from the gas-liquid separator is introduced into the heat exchanger together with the evaporated gas generated in the storage tank. 제 5항에 있어서,
상기 팽창 수단은 상기 기액분리기의 전단에 마련되는 적어도 하나의 감압밸브 또는 팽창기를 포함하고,
상기 기액분리기의 후단에는 상기 저장탱크로 회수되는 액화천연가스를 감압하는 제1 감압밸브와, 상기 열교환기로 도입되는 기체를 감압하는 제2 감압밸브가 마련되는 것을 특징으로 하는 증발가스 재액화 시스템. 6. The method of claim 5,
Wherein the expansion means includes at least one pressure reducing valve or an expander provided at a front end of the gas-liquid separator,
And a second pressure reducing valve for reducing the pressure of the gas introduced into the heat exchanger is provided at a rear end of the gas-liquid separator, the first pressure reducing valve reducing the pressure of the liquefied natural gas recovered to the storage tank. 제 1항에 있어서,
상기 컴프레서에서 상기 증발가스는 150 내지 400 bar의 압력으로 압축되고,
상기 컴프레서에서 압축된 상기 증발가스 중 적어도 일부는 상기 선박 또는 해양 구조물의 엔진 연료로 공급되는 것을 특징으로 하는 증발가스 재액화 시스템.The method according to claim 1,
Wherein the evaporation gas in the compressor is compressed to a pressure of from 150 to 400 bar,
Wherein at least a portion of the evaporated gas compressed in the compressor is supplied to the engine fuel of the vessel or offshore structure. 제 7항에 있어서,
상기 컴프레서에서 압축된 상기 증발가스 중 적어도 일부를 공급받는 주 엔진; 및
상기 컴프레서 중 일부를 거쳐 압축되어 상기 열교환기로 도입되는 상기 압축된 증발가스 중 적어도 일부를 공급받은 부 엔진을 더 포함하는 증발가스 재액화 시스템.8. The method of claim 7,
A main engine for receiving at least a portion of the evaporated gas compressed in the compressor; And
Further comprising a sub-engine that is supplied with at least a portion of the compressed evaporative gas compressed through a portion of the compressor and introduced into the heat exchanger. 1) 선박 또는 해양 구조물의 저장탱크에서 발생하는 증발가스를 컴프레서로 압축하는 단계;
2) 압축된 증발가스를 분기하고 열교환기로 도입시켜, 상기 저장탱크에서 발생한 압축 전의 증발가스와 열교환시키는 단계; 및
3) 열교환된 상기 증발가스를 단열팽창시키고 기액분리하는 단계;를 포함하고,
상기 컴프레서는 압축 및 중간 냉각이 반복되는 다단 압축기로 상기 다단 압축기 중 일부에는 마모방지를 위한 오일이 공급되고, 상기 다단 압축기 중 오일 공급 전의 압축기만을 거친 상기 압축된 증발가스가 상기 열교환기로 도입되는 것을 특징으로 하는 증발가스 재액화 방법.1) compressing the evaporative gas generated in the storage tank of a ship or an offshore structure by a compressor;
2) introducing the compressed evaporated gas into a heat exchanger to heat-exchange the evaporated gas before compression generated in the storage tank; And
3) a step of thermally expanding and vapor-liquid separating the heat-exchanged evaporated gas,
Wherein the compressor is a multi-stage compressor in which compression and intermediate cooling are repeated, and oil for preventing wear is supplied to a part of the multi-stage compressor, and the compressed evaporative gas passing through only the compressor before oil supply from the multi-stage compressor is introduced into the heat exchanger Wherein the evaporating gas is liquid.
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