KR20220027336A - Flow control system used for liquefaction of lng - Google Patents

Flow control system used for liquefaction of lng Download PDF

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KR20220027336A
KR20220027336A KR1020200107819A KR20200107819A KR20220027336A KR 20220027336 A KR20220027336 A KR 20220027336A KR 1020200107819 A KR1020200107819 A KR 1020200107819A KR 20200107819 A KR20200107819 A KR 20200107819A KR 20220027336 A KR20220027336 A KR 20220027336A
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flow rate
lng
refrigerant
value
rate value
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KR1020200107819A
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Korean (ko)
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이기환
김문규
김민기
김효빈
박현기
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삼성중공업 주식회사
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    • 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
    • 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
    • F25J1/0047—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 an "external" refrigerant stream in a closed vapor compression cycle
    • F25J1/005—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 an "external" refrigerant stream in a closed vapor compression cycle by expansion of a gaseous refrigerant stream with extraction of work
    • 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
    • F25J1/0047—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 an "external" refrigerant stream in a closed vapor compression cycle
    • F25J1/0052—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 an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream
    • F25J1/0057—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 an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream after expansion of the liquid refrigerant stream with extraction of work
    • 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
    • F25J1/0211—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 a multi-component refrigerant [MCR] fluid in a closed vapor compression cycle
    • F25J1/0212—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 a multi-component refrigerant [MCR] fluid in a closed vapor compression cycle as a single flow MCR cycle
    • 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
    • F25J1/0244—Operation; Control and regulation; Instrumentation
    • F25J1/0245—Different modes, i.e. 'runs', of operation; Process control
    • 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
    • F25J1/0254—Operation; Control and regulation; Instrumentation controlling particular process parameter, e.g. pressure, temperature
    • 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
    • F25J1/0278—Unit being stationary, e.g. on floating barge or fixed platform
    • 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.
    • F25J1/0285—Combination of different types of drivers mechanically coupled to the same refrigerant compressor, possibly split on multiple compressor casings
    • F25J1/0288—Combination of different types of drivers mechanically coupled to the same refrigerant compressor, possibly split on multiple compressor casings using work extraction by mechanical coupling of compression and expansion of the refrigerant, so-called companders
    • 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
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/66—Separating acid gases, e.g. CO2, SO2, H2S or RSH
    • 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
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/12—Particular process parameters like pressure, temperature, ratios

Abstract

Disclosed is a flow rate adjustment system for LNG liquefaction. According to an embodiment of the present invention, the flow rate adjustment system for the LNG liquefaction includes: a heat exchanger configured to generate an LNG by performing heat exchange between a refrigerant compressed, cooled, and expanded by a compressor, a cooler, and an expander and a natural gas, and connected to a storage tank for storing the LNG through a supply line; a high selector for selecting a higher value by comparing an LNG flow rate value that is input to increase a LNG flow rate with a preset LNG flow rate value; an LNG flow rate controller for adjusting an LNG flow rate value provided in the supply line based on the LNG flow rate value selected by the high selector; a low selector for selecting a lower value between a current LNG flow rate value that is gradually increased according to the LNG flow rate value selected by the high selector and the LNG flow rate value that is input to increase the LNG flow rate by comparing the current LNG flow rate value with the LNG flow rate value that is input to increase the LNG flow rate; and a refrigerant flow rate controller for adjusting a flow rate of the refrigerant expanded by the expander based on the LNG flow rate value selected by the low selector. Accordingly, efficiency of an LNG liquefaction process is increased.

Description

LNG 액화용 유량 조절 시스템{FLOW CONTROL SYSTEM USED FOR LIQUEFACTION OF LNG} Flow control system for LNG liquefaction

본 발명은 LNG 액화용 유량 조절 시스템에 관한 것이다.The present invention relates to a flow control system for LNG liquefaction.

천연가스를 액화시켜 액화천연가스(LNG, Liquefied Natural Gas)로 생성하는 LNG 액화공정에 있어서, 압축, 냉각 및 팽창 과정을 거친 냉매는 열교환기에 의해 천연가스와 열교환되고, 냉매와의 열교환 과정을 거친 천연가스는 LNG로 생성되어 저장탱크에 저장된다. In the LNG liquefaction process for liquefying natural gas to produce liquefied natural gas (LNG), the refrigerant that has undergone compression, cooling, and expansion processes is heat-exchanged with natural gas by a heat exchanger and undergoes heat exchange with the refrigerant. Natural gas is generated as LNG and stored in a storage tank.

LNG 액화공정은 냉매의 종류 및 냉각 방식이 전체 효율에 영향을 미친다. 냉매에 액상이 존재하는 경우, 줄톰슨 밸브를 이용하여 냉매를 냉각시킨다. 액상 냉매는 보통 열용량이 높아 효율이 좋지만 선상 움직임에 따른 액상 냉매의 불규칙한 움직임으로 인해 해양플랜트 적용에 단점으로 작용한다. 기상 냉매는 액상 냉매보다 열용량은 낮지만 선상 움직임에 영향을 받지 않아 해양 플랜트 적용에 강점을 가진다. In the LNG liquefaction process, the type of refrigerant and cooling method affect the overall efficiency. When a liquid phase exists in the refrigerant, the refrigerant is cooled using a Joule Thompson valve. Liquid refrigerant usually has high heat capacity, so the efficiency is good, but due to the irregular movement of the liquid refrigerant according to the movement of the ship, it acts as a disadvantage in offshore plant applications. Gas phase refrigerant has a lower heat capacity than liquid refrigerant, but it is not affected by shipboard movement, so it has strengths in offshore plant applications.

한편, LNG의 유량이 변하면 이에 맞게 냉매의 유량도 조절되어야 한다. 예컨대 종래에는 LNG의 유량이 급격하게 변화될 때 열교환기에 열충격(Thermal Shock)이 발생할 수 있었다.On the other hand, when the flow rate of LNG changes, the flow rate of the refrigerant must be adjusted accordingly. For example, conventionally, when the flow rate of LNG is rapidly changed, a thermal shock may occur in the heat exchanger.

관련 기술로서, 한국공개특허 제10-2012-0005158호(2012.01.16. 공개)를 참조하기 바란다.As a related art, please refer to Korean Patent Application Laid-Open No. 10-2012-0005158 (published on January 16, 2012).

한국공개특허 제10-2012-0005158호(2012.01.16. 공개)Korean Patent Publication No. 10-2012-0005158 (published on January 16, 2012)

본 발명의 실시 예는 LNG 또는 냉매의 유량 변화에 효과적으로 대응하여 LNG 액화공정의 효율성을 높일 수 있는 LNG 액화용 유량 조절 시스템을 제공하고자 한다.An embodiment of the present invention is to provide a flow rate control system for LNG liquefaction that can increase the efficiency of the LNG liquefaction process by effectively responding to a change in the flow rate of LNG or refrigerant.

본 발명의 일 측면에 따르면, 압축기, 냉각기 및 팽창기에 의해 압축, 냉각 및 팽창이 이루어진 냉매와 천연가스 간 열교환을 수행하여 LNG를 생성하고, 상기 LNG를 저장하는 저장탱크와 공급라인을 통해 연결된 열교환기; 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 미리 설정된 LNG 유량값을 비교하여 높은 값을 선택하는 하이셀렉터; 상기 하이셀렉터에 의해 선택된 LNG 유량값을 기초로 상기 공급라인에 마련된 LNG 유량밸브를 조절하는 LNG유량제어기; 상기 하이셀렉터에 의해 선택된 LNG 유량값에 따라 점차적으로 증가하는 LNG의 현재 유량값을 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택하는 로우셀렉터; 및 상기 로우셀렉터에 의해 선택된 LNG 유량값을 기초로 상기 팽창기에 의해 팽창되는 냉매의 유량을 조절하는 냉매유량제어기;를 포함하는 LNG 액화용 유량 조절 시스템이 제공될 수 있다. According to one aspect of the present invention, LNG is generated by performing heat exchange between natural gas and a refrigerant that has been compressed, cooled and expanded by a compressor, a cooler and an expander, and heat exchange is connected to a storage tank for storing the LNG through a supply line. energy; a high selector for selecting a high value by comparing an input LNG flow rate value and a preset LNG flow rate value for increasing the LNG flow rate; an LNG flow controller that adjusts the LNG flow valve provided in the supply line based on the LNG flow rate value selected by the high selector; a low selector which compares a current flow rate value of LNG, which is gradually increased according to the LNG flow rate value selected by the high selector, with an LNG flow rate value input for increasing the LNG flow rate, and selects a lower value from the two; and a refrigerant flow rate controller that adjusts the flow rate of the refrigerant expanded by the expander based on the LNG flow rate value selected by the row selector.

상기 공급라인을 통해 흐르는 LNG의 유량을 측정하는 제1측정기와, 상기 LNG의 압력을 측정하는 제2측정기와, 상기 LNG의 온도를 측정하는 제3측정기와, 상기 측정된 LNG의 유량, 압력, 온도 값을 기초로 상기 공급라인을 통해 흐르는 LNG의 현재 유량값을 산출하는 제1산출부를 더 포함하되, 상기 LNG유량제어기는 상기 제1산출부에 의해 산출된 LNG의 현재 유량값을 고려하여 상기 하이셀렉터에 의해 선택된 LNG 유량값에 도달하도록 상기 공급라인에 마련된 LNG 유량밸브를 조절하고, 상기 로우셀렉터는 상기 제1산출부에 의해 산출된 LNG의 현재 유량값을 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택하는 것일 수 있다.A first measuring device for measuring the flow rate of LNG flowing through the supply line, a second measuring device for measuring the pressure of the LNG, a third measuring device for measuring the temperature of the LNG, the measured flow rate and pressure of the LNG; Further comprising a first calculation unit for calculating a current flow rate value of the LNG flowing through the supply line based on the temperature value, wherein the LNG flow controller considers the current flow rate value of the LNG calculated by the first calculation unit. The LNG flow valve provided in the supply line is adjusted to reach the LNG flow rate value selected by the high selector, and the low selector receives the current flow value of LNG calculated by the first calculator to increase the LNG flow rate. It may be to select the lower value of the two compared to the LNG flow rate.

상기 로우셀렉터에 의해 선택된 LNG 유량값을 미리 설정된 수식에 대입하여 냉매 유량값을 산출하는 냉매유량산출부와, 상기 공급라인을 통해 흐르는 LNG의 온도값을 기초로 상기 냉매유량산출부에 의해 산출된 냉매 유량값을 보정하는 냉매유량보정부를 더 포함하되, 상기 냉매유량제어기는 상기 보정된 냉매 유량값을 수신한 경우, 상기 보정된 냉매 유량값에 따라 상기 팽창기에 의해 팽창되는 냉매의 유량을 조절할 수 있다.A refrigerant flow rate calculating unit calculating a refrigerant flow rate value by substituting the LNG flow rate value selected by the row selector into a preset equation, and the refrigerant flow rate calculating unit calculated by the refrigerant flow rate calculating unit based on the temperature value of the LNG flowing through the supply line Further comprising a refrigerant flow rate correction unit for correcting a refrigerant flow rate value, wherein the refrigerant flow rate controller, when receiving the corrected refrigerant flow rate value, adjust the flow rate of the refrigerant expanded by the expander according to the corrected refrigerant flow rate value there is.

상기 냉각기를 거쳐 상기 팽창기로 흐르는 냉매의 유량을 측정하는 제4측정기와, 상기 냉매의 압력을 측정하는 제5측정기와, 상기 냉매의 온도를 측정하는 제6측정기와, 상기 측정된 냉매의 유량, 압력, 온도 값을 기초로 냉매의 현재 유량값을 산출하는 제2산출부를 더 포함하되, 상기 냉매유량제어기는 상기 제2산출부에 의해 산출된 냉매의 현재 유량값을 고려하여 상기 냉매유량보정부에 의해 보정된 냉매 유량값에 따라 상기 팽창기에 의해 팽창되는 냉매의 유량을 조절할 수 있다.A fourth measuring instrument for measuring the flow rate of the refrigerant flowing through the cooler to the expander, a fifth measuring instrument for measuring the pressure of the refrigerant, a sixth measuring instrument for measuring the temperature of the refrigerant, the measured flow rate of the refrigerant; Further comprising a second calculation unit for calculating a current flow rate value of the refrigerant based on the pressure and temperature values, wherein the refrigerant flow controller is the refrigerant flow rate correction unit in consideration of the current flow rate value of the refrigerant calculated by the second calculation unit The flow rate of the refrigerant expanded by the expander may be adjusted according to the refrigerant flow rate value corrected by .

상기 산출된 냉매의 현재 유량값을 미리 설정된 수식에 대입하여 LNG 유량값을 산출하는 LNG유량산출부와, 상기 공급라인을 통해 흐르는 LNG의 온도값을 기초로 상기 LNG유량산출부에 의해 산출된 LNG 유량값을 보정하는 LNG유량보정부를 더 포함하되, 상기 하이셀렉터는 상기 보정된 LNG 유량값을 수신한 경우, 상기 보정된 LNG 유량값을 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 높은 값을 선택할 수 있다.An LNG flow rate calculating unit calculating an LNG flow rate value by substituting the calculated current flow rate value of the refrigerant into a preset formula, and the LNG calculated by the LNG flow rate calculating unit based on the temperature value of the LNG flowing through the supply line and an LNG flow rate correction unit for correcting the flow rate value, wherein the high selector compares the corrected LNG flow rate value with the LNG flow rate value input for increasing the LNG flow rate when receiving the corrected LNG flow rate value. You can choose a value.

본 발명의 실시 예에 따른 LNG 액화용 유량 조절 시스템은 LNG 또는 냉매의 유량 변화에 효과적으로 대응하여 LNG 액화공정의 효율성을 높일 수 있다.The flow control system for LNG liquefaction according to an embodiment of the present invention can effectively respond to changes in the flow rate of LNG or refrigerant to increase the efficiency of the LNG liquefaction process.

본 발명의 효과들은 이상에서 언급한 효과들로 제한되지 않으며, 언급되지 않은 또 다른 효과들은 청구범위의 기재로부터 당업자에게 명확하게 이해될 수 있을 것이다.Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

도 1은 본 발명의 실시 예에 따른 LNG 액화용 유량 조절 시스템을 나타낸다.1 shows a flow rate control system for LNG liquefaction according to an embodiment of the present invention.

이하에서는 본 발명의 실시 예들을 첨부 도면을 참조하여 상세히 설명한다. 이하에 소개되는 실시 예들은 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 본 발명의 사상이 충분히 전달될 수 있도록 하기 위해 예로서 제공되는 것이다. 본 발명은 이하 설명되는 실시 예들에 한정되지 않고 다른 형태로 구체화될 수도 있다. 본 발명을 명확하게 설명하기 위하여 설명과 관계없는 부분은 도면에서 생략하였으며 도면들에 있어서, 구성요소의 폭, 길이, 두께 등은 편의를 위하여 과장되어 표현될 수 있다. 명세서 전체에 걸쳐서 동일한 참조번호들은 동일한 구성요소들을 나타낸다.Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the embodiments described below and may be embodied in other forms. In order to clearly explain the present invention, parts irrelevant to the description are omitted from the drawings, and in the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals refer to like elements throughout.

도 1을 참조하면, 본 발명의 실시 예에 따른 LNG 액화용 유량 조절 시스템은 압축기(11), 냉각기(12) 및 팽창기(13)에 의해 압축, 냉각 및 팽창이 이루어진 냉매와 천연가스 간 열교환을 수행하여 LNG를 생성하고, LNG를 저장하는 저장탱크(15)와 공급라인(L1)을 통해 연결된 열교환기(10)와, LNG 유량 증가를 위해 입력된 LNG 유량값과 미리 설정된 LNG 유량값을 비교하여 높은 값을 선택하는 하이셀렉터(20)와, 하이셀렉터(20)에 의해 선택된 LNG 유량값을 기초로 공급라인(L1)에 마련된 LNG 유량밸브(V1)를 조절하는 LNG유량제어기(30)와, 하이셀렉터(20)에 의해 선택된 LNG 유량값에 따라 공급라인(L1)을 통해 흐르는 점차적으로 증가하는 LNG의 현재 유량값을 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택하는 로우셀렉터(40)와, 로우셀렉터(40)에 의해 선택된 LNG 유량값을 기초로 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절하는 냉매유량제어기(50)를 포함한다.Referring to FIG. 1 , the flow control system for LNG liquefaction according to an embodiment of the present invention performs heat exchange between a refrigerant compressed, cooled and expanded by a compressor 11 , a cooler 12 , and an expander 13 and natural gas. A storage tank 15 for generating LNG and storing the LNG and a heat exchanger 10 connected through a supply line L1, and an LNG flow rate input to increase the LNG flow rate and a preset LNG flow rate value are compared high selector 20 to select a high value, and an LNG flow controller 30 for controlling the LNG flow valve V1 provided in the supply line L1 based on the LNG flow rate value selected by the high selector 20; , by comparing the current flow value of the gradually increasing LNG flowing through the supply line L1 according to the LNG flow rate value selected by the high selector 20 with the LNG flow rate input for increasing the LNG flow rate, the lower of the two The selected row selector 40 includes a refrigerant flow controller 50 that adjusts the flow rate of the refrigerant expanded by the expander 13 based on the LNG flow rate value selected by the row selector 40 .

또, LNG 액화용 유량 조절 시스템은 공급라인(L1)을 통해 흐르는 LNG의 유량을 측정하는 제1측정기(61)와, LNG의 압력을 측정하는 제2측정기(62)와, LNG의 온도를 측정하는 제3측정기(63)와, 측정된 LNG의 유량, 압력, 온도 값을 기초로 공급라인(L1)을 통해 흐르는 LNG의 현재 유량값을 산출하는 제1산출부(60)를 포함할 수 있다. In addition, the flow control system for LNG liquefaction includes a first measuring device 61 measuring the flow rate of LNG flowing through the supply line L1, a second measuring device 62 measuring the pressure of the LNG, and measuring the temperature of the LNG. It may include a third measuring device 63 that calculates the current flow rate value of LNG flowing through the supply line L1 based on the measured flow rate, pressure, and temperature values of the LNG. .

여기서, 상술한 LNG유량제어기(30)는 제1산출부(60)에 의해 산출된 LNG의 현재 유량값을 고려하여 하이셀렉터(20)에 의해 선택된 LNG 유량값에 도달하도록 공급라인(L1)에 마련된 LNG 유량밸브(V1)를 조절한다. 그리고, 상술한 로우셀렉터(40)는 제1산출부(60)에 의해 산출된 LNG의 현재 유량값을 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택한다.Here, the above-described LNG flow rate controller 30 is connected to the supply line L1 to reach the LNG flow rate value selected by the high selector 20 in consideration of the current flow rate value of LNG calculated by the first calculation unit 60 . Adjust the provided LNG flow valve (V1). In addition, the above-described row selector 40 compares the current flow rate value of LNG calculated by the first calculation unit 60 with the LNG flow rate value input to increase the LNG flow rate and selects a lower value from the two.

또, LNG 액화용 유량 조절 시스템은 로우셀렉터(40)에 의해 선택된 LNG 유량값을 미리 설정된 수식에 대입하여 냉매 유량값을 산출하는 냉매유량산출부(72)와, 공급라인(L1)을 통해 흐르는 LNG의 온도값을 기초로 냉매유량산출부(72)에 의해 산출된 냉매 유량값을 보정하는 냉매유량보정부(74)를 포함할 수 있다.In addition, the flow rate control system for LNG liquefaction includes a refrigerant flow rate calculation unit 72 that calculates a refrigerant flow rate value by substituting the LNG flow rate value selected by the row selector 40 into a preset equation, and the supply line L1 flowing through It may include a refrigerant flow rate correction unit 74 for correcting the refrigerant flow rate value calculated by the refrigerant flow rate calculating unit 72 based on the temperature value of the LNG.

여기서, 상술한 냉매유량제어기(50)는 냉매유량보정부(74)로부터 보정된 냉매 유량값을 수신한 경우, 보정된 냉매 유량값에 따라 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절한다.Here, the above-described refrigerant flow rate controller 50 adjusts the flow rate of the refrigerant expanded by the expander 13 according to the corrected refrigerant flow rate value when receiving the corrected refrigerant flow rate value from the refrigerant flow rate correcting unit 74. .

또, LNG 액화용 유량 조절 시스템은 냉매가 순환하는 순환라인(L2) 상의 냉각기(12)를 거쳐 팽창기(13)로 흐르는 냉매의 유량을 측정하는 제4측정기(81)와, 냉매의 압력을 측정하는 제5측정기(82)와, 냉매의 온도를 측정하는 제6측정기(83)와, 측정된 냉매의 유량, 압력, 온도 값을 기초로 순환라인(L2)을 통해 흐르는 냉매의 현재 유량값을 산출하는 제2산출부(80)를 포함할 수 있다.In addition, the flow control system for LNG liquefaction includes a fourth measuring device 81 that measures the flow rate of the refrigerant flowing to the expander 13 through the cooler 12 on the circulation line L2 through which the refrigerant circulates, and the pressure of the refrigerant The current flow value of the refrigerant flowing through the circulation line (L2) based on the fifth measuring instrument 82, the sixth measuring instrument 83 measuring the temperature of the refrigerant, and the measured refrigerant flow rate, pressure, and temperature values. It may include a second calculation unit 80 to calculate.

여기서, 상술한 냉매유량제어기(50)는 제2산출부(80)에 의해 산출된 냉매의 현재 유량값을 고려하여 냉매유량보정부(74)에 의해 보정된 냉매 유량값에 따라 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절한다.Here, the above-described refrigerant flow rate controller 50 is the expander 13 according to the refrigerant flow rate value corrected by the refrigerant flow rate correction unit 74 in consideration of the current flow rate value of the refrigerant calculated by the second calculation unit 80. Controls the flow rate of the refrigerant expanded by

또, LNG 액화용 유량 조절 시스템은 제2산출부(80)에 의해 산출된 냉매의 현재 유량값을 미리 설정된 수식에 대입하여 LNG 유량값을 산출하는 LNG유량산출부(92)와, 공급라인(L1)을 통해 흐르는 LNG의 온도값을 기초로 LNG유량산출부(92)에 의해 산출된 LNG 유량값을 보정하는 LNG유량보정부(94)를 포함할 수 있다.In addition, the flow rate control system for LNG liquefaction includes an LNG flow rate calculation unit 92 that calculates the LNG flow rate value by substituting the current flow rate value of the refrigerant calculated by the second calculation unit 80 into a preset equation, and a supply line ( It may include an LNG flow rate correction unit 94 for correcting the LNG flow rate value calculated by the LNG flow rate calculating unit 92 based on the temperature value of the LNG flowing through L1).

여기서, 하이셀렉터(20)는 LNG유량보정부(94)로부터 보정된 LNG 유량값을 수신한 경우, 보정된 LNG 유량값을 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 높은 값을 선택한다.Here, when the high selector 20 receives the corrected LNG flow rate value from the LNG flow rate correction unit 94, the high selector 20 compares the corrected LNG flow rate value with the input LNG flow rate value to increase the LNG flow rate and selects a high value. .

이하, LNG 액화용 유량 조절 시스템의 구성요소 및 동작과정에 대해서 구체적으로 설명한다.Hereinafter, the components and operation process of the flow control system for LNG liquefaction will be described in detail.

도 1에 도시한 바와 같이, 열교환기(10)는 압축기(11), 냉각기(12) 및 팽창기(13)에 의해 압축, 냉각 및 팽창이 이루어진 냉매와 천연가스 간 열교환을 수행하여 LNG를 생성한다. 이러한 LNG는 공급라인(L1)을 통해 저장탱크(15)에 저장된다.As shown in FIG. 1 , the heat exchanger 10 performs heat exchange between natural gas and a refrigerant that has been compressed, cooled and expanded by a compressor 11 , a cooler 12 and an expander 13 to generate LNG. . Such LNG is stored in the storage tank 15 through the supply line L1.

여기서, 냉매는 순환라인(L2)을 통해 순환하며, 순환라인(L2) 상에는 압축기(11), 냉각기(12) 및 팽창기(13)가 순차적으로 배치되어 있어 압축, 냉각 및 팽창이 이루어진 냉매가 열교환기(10)로 공급되어 천연가스와 열교환된다. 천연가스는 열교환기(10)에 의해 냉매와 열교환된 후 액화되어 LNG로 변환되고, 공급라인(L1)을 통해 저장탱크(15)에 저장된다.Here, the refrigerant circulates through the circulation line L2, and the compressor 11, the cooler 12, and the expander 13 are sequentially arranged on the circulation line L2, so that the refrigerant that has been compressed, cooled and expanded is heat exchanged. It is supplied to the unit 10 to exchange heat with natural gas. The natural gas is liquefied after heat exchange with the refrigerant by the heat exchanger 10 , is converted into LNG, and is stored in the storage tank 15 through the supply line L1 .

이러한 LNG 액화공정에 사용되는 냉매와 LNG 유량은 예컨대 초기에 ‘5’의 유량값을 갖고 1:1의 비율로 설정될 수 있다. 즉, 운전자가 입력부(2)를 통해 ‘5’의 LNG 유량값을 입력하면, 냉매 유량값 설정부(4)에 설정된 냉매 유량 제한 제한값과 비교되어 선택부(6)에 의해 낮은 값이 선택된다. 참고로 냉매 유량 제한 제한값은 냉매 압축기(11)의 파워와 관련되어 있다. 선택부(6)에 의해 낮은 값으로 5의 값이 선택되면, 하이셀렉터(20)와 로우셀렉터(40)에 초기 설정값으로 ‘5’의 값이 설정된다. The refrigerant and the LNG flow rate used in the LNG liquefaction process may initially have a flow rate value of '5' and may be set at a ratio of 1:1. That is, when the driver inputs the LNG flow rate value of '5' through the input unit 2 , it is compared with the refrigerant flow rate limiting limit value set in the refrigerant flow rate value setting unit 4 , and a lower value is selected by the selection unit 6 . . For reference, the refrigerant flow limit limit value is related to the power of the refrigerant compressor 11 . When a value of 5 is selected as a low value by the selector 6 , a value of ‘5’ is set as an initial set value in the high selector 20 and the low selector 40 .

이후, LNG 유량 증가를 위해, LNG 유량값을 ‘6’으로 입력하면, 하이셀렉터(20)는 LNG 유량 증가를 위해 입력된 LNG 유량값과 미리 설정된 LNG 유량값을 비교하여 둘 중 높은 값인 ‘6’을 선택한다.Thereafter, when an LNG flow rate value is input as '6' to increase the LNG flow rate, the high selector 20 compares the input LNG flow rate value for increasing the LNG flow rate with a preset LNG flow rate value, and the higher value of the two values is '6'. Select '.

다음으로, LNG유량제어기(30)는 하이셀렉터(20)에 의해 선택된 LNG 유량값을 기초로 공급라인(L1)에 마련된 LNG 유량밸브(V1)를 조절한다.Next, the LNG flow controller 30 controls the LNG flow valve V1 provided in the supply line L1 based on the LNG flow rate value selected by the high selector 20 .

이때, LNG유량제어기(30)는 공급라인(L1)을 통해 흐르는 LNG의 현재 유량값을 고려하여 하이셀렉터(20)에 의해 선택된 LNG 유량값에 도달하도록 공급라인(L1)에 마련된 LNG 유량밸브(V1)를 조절한다. 공급라인(L1)을 통해 흐르는 LNG의 현재 유량값은 제1산출부(60)에 의해 산출된 값으로, 제1산출부(60)는 공급라인(L1)에 마련된 측정기(61~63)에 의해 측정된 LNG의 유량, 압력, 온도 값을 기초로 공급라인(L1)을 통해 흐르는 LNG의 현재 유량을 산출할 수 있다.At this time, the LNG flow controller 30 considers the current flow value of LNG flowing through the supply line L1 to reach the LNG flow rate value selected by the high selector 20. The LNG flow valve ( V1) is adjusted. The current flow rate value of LNG flowing through the supply line L1 is a value calculated by the first calculation unit 60, and the first calculation unit 60 is connected to the measuring instruments 61 to 63 provided in the supply line L1. It is possible to calculate the current flow rate of LNG flowing through the supply line (L1) based on the flow rate, pressure, and temperature values of the measured LNG.

여기서, 제1측정기(61)에 의해 측정된 LNG의 유량 값은 dp(differential pressure) 즉 제1측정기(61)를 통과하기 전과 후의 압력 차이 또는 부피 유량(㎥/h) 값으로, 측정기의 종류에 따라 다를 수 있다. dP 또는 부피 유량 값은 압력 및 온도에 따라 차이가 크게 발생할 수 있으며, 따라서 제1산출부(60)는 제2 및 제3측정기(62,63)에 의해 측정된 압력 및 온도 값으로 제1측정기(61)에 의해 측정된 값을 보정하여 질량 유량(kg/h)으로 환산할 수 있다. 압력 및 온도 값으로 질량 유량으로 환산하는 수식은 기체 또는 액체의 종류에 따라 다르며, 사전에 정한 수식 또는 실험값으로 정해질 수 있다. 이는 후술할 제2산출부(80)에도 마찬가지로 적용될 수 있다.Here, the flow rate value of LNG measured by the first measuring device 61 is dp (differential pressure), that is, the pressure difference or volumetric flow rate (m3/h) value before and after passing through the first measuring device 61, and the type of the measuring device may vary depending on The dP or volume flow value may have a large difference depending on pressure and temperature, and thus the first calculation unit 60 uses the pressure and temperature values measured by the second and third measuring instruments 62 and 63 as the first measuring instrument. (61) can be converted to mass flow rate (kg/h) by correcting the measured value. The formula for converting the pressure and temperature values into mass flow rates varies depending on the type of gas or liquid, and may be determined by a predetermined formula or an experimental value. This may also be applied to the second calculation unit 80, which will be described later.

하이셀렉터(20)에 의해 선택된 LNG 유량값에 따라 점차적으로 증가하는 공급라인(L1)을 통해 흐르는 LNG의 현재 유량값은 로우셀렉터(40)로 보내진다. The current flow rate value of LNG flowing through the supply line L1 which gradually increases according to the LNG flow rate value selected by the high selector 20 is sent to the low selector 40 .

그러면, 로우셀렉터(40)는 하이셀렉터(20)에 의해 선택된 LNG 유량값에 따라 공급라인(L1)을 통해 흐르는 점차적으로 증가하는 LNG의 현재 유량값을 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택한다. 예컨대, 공급라인(L1)을 통해 흐르는 LNG의 현재 유량값으로 ‘5.5’값을 입력받은 경우, 로우셀렉터(40)는 LNG 유량 증가를 위해 입력된 LNG 유량값‘6’값과 비교하여 낮은 값인 ‘5.5’값을 선택한다.Then, the low selector 40 sets the gradually increasing current flow rate value of LNG flowing through the supply line L1 according to the LNG flow rate value selected by the high selector 20 to the LNG flow rate input for increasing the LNG flow rate and Compare and choose the lower value of the two. For example, when a value of '5.5' is input as the current flow rate value of LNG flowing through the supply line L1, the low selector 40 sets the low value compared to the LNG flow rate value '6' input to increase the LNG flow rate. Choose a value of '5.5'.

다음으로, 냉매유량제어기(50)는 로우셀렉터(40)에 의해 선택된 LNG 유량값을 기초로 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절한다. 이때, 냉매유량제어기(50)는 팽창기(13)의 IGV(14, Inlet Guide Vane)를 제어하는 방법으로 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절할 수 있다.Next, the refrigerant flow controller 50 adjusts the flow rate of the refrigerant expanded by the expander 13 based on the LNG flow rate value selected by the row selector 40 . At this time, the refrigerant flow controller 50 may control the flow rate of the refrigerant expanded by the expander 13 by controlling the IGV (14, Inlet Guide Vane) of the expander 13 .

냉매유량제어기(50)는 순환라인(L2)을 통해 흐르는 냉매의 현재 유량값을 고려하여 로우셀렉터(40)에 의해 선택된 냉매 유량값에 도달하도록 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절할 수 있다.The refrigerant flow controller 50 adjusts the flow rate of the refrigerant expanded by the expander 13 to reach the refrigerant flow rate value selected by the row selector 40 in consideration of the current flow rate value of the refrigerant flowing through the circulation line L2 can

순환라인(L2)을 통해 흐르는 냉매의 현재 유량값은 냉각기(12)를 거쳐 팽창기(13)로 흐르는 냉매의 유량, 압력, 및 온도를 측정기(81~83)에 의해 측정하고, 측정된 냉매의 유량, 압력, 온도 값을 기초로 제2산출부(80)에 의해 산출된 값이다.The current flow value of the refrigerant flowing through the circulation line (L2) is measured by measuring the flow rate, pressure, and temperature of the refrigerant flowing to the expander 13 through the cooler 12 by the measuring instruments 81 to 83, and It is a value calculated by the second calculation unit 80 based on the flow rate, pressure, and temperature values.

이때, 냉매유량산출부(72)와 냉매유량보정부(74)가 마련된 경우, 냉매유량제어기(50)는 제2산출부(80)에 의해 산출된 냉매의 현재 유량값을 고려하여 냉매유량보정부(74)에 의해 보정된 냉매 유량값에 따라 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절할 수 있다. 냉매유량산출부(72)와 냉매유량보정부(74)는 다른 예에서 생략될 수 있다.At this time, when the refrigerant flow rate calculating unit 72 and the refrigerant flow rate correcting unit 74 are provided, the refrigerant flow rate controller 50 calculates the refrigerant flow rate in consideration of the current flow rate value of the refrigerant calculated by the second calculating unit 80 . The flow rate of the refrigerant expanded by the expander 13 may be adjusted according to the refrigerant flow rate value corrected by the government 74 . The refrigerant flow rate calculating unit 72 and the refrigerant flow rate correcting unit 74 may be omitted in other examples.

냉매유량산출부(72)는 로우셀렉터(40)에 의해 선택된 LNG 유량값을 미리 설정된 수식에 대입하여 냉매 유량값을 산출하고, 냉매유량보정부(74)는 공급라인(L1)을 통해 흐르는 LNG의 온도값을 기초로 냉매유량산출부(72)에 의해 산출된 냉매 유량값을 보정한다.The refrigerant flow rate calculating unit 72 calculates the refrigerant flow rate value by substituting the LNG flow rate value selected by the row selector 40 into a preset equation, and the refrigerant flow rate correcting unit 74 is the LNG flowing through the supply line L1. The refrigerant flow rate value calculated by the refrigerant flow rate calculating unit 72 is corrected based on the temperature value of .

예컨대, 냉매유량산출부(72)는 냉매와 LNG 유량비가 1:1로 설정된 경우 로우셀렉터(40)로부터 LNG 유량값으로 ‘5.5’값을 수신하면, 냉매 유량값을 ‘5.5’로 산출한다. 냉매와 LNG의 유량비는 미리 산출된 값이거나 실험으로 결정한 값일 수 있다. 다른 예로서 1.7:1 비율로 냉매와 LNG의 유량비가 설정된 경우, ‘5.5’의 LNG 유량값에 대해 냉매 유량값은 ‘9.35’로 산출된다.For example, when the refrigerant flow rate calculation unit 72 receives a value of '5.5' as the LNG flow rate value from the row selector 40 when the refrigerant and LNG flow rate ratio is set to 1:1, the refrigerant flow rate calculation unit 72 calculates the refrigerant flow rate value as '5.5'. The flow ratio between the refrigerant and the LNG may be a value calculated in advance or a value determined by an experiment. As another example, when the flow rate ratio of refrigerant and LNG is set at a ratio of 1.7:1, the refrigerant flow rate value is calculated as ‘9.35’ for the LNG flow rate value of ‘5.5’.

냉매유량보정부(74)는 냉매유량산출부(72)로부터 수신한 냉매 유량값을 냉매유량제어기(50)로 보내기 앞서 미세한 조정을 하며, 이는 LNG의 온도값에 따라 결정될 수 있다.The refrigerant flow rate correction unit 74 finely adjusts the refrigerant flow rate value received from the refrigerant flow rate calculating unit 72 before sending it to the refrigerant flow rate controller 50, which may be determined according to the temperature value of the LNG.

즉, 냉매유량보정부(74)는 온도제어기(65)로부터 공급라인(L1)을 통해 흐르는 LNG의 현재 온도를 수신하고, 이를 기초로 냉매유량산출부(72)로부터 수신한 냉매 유량값을 보정한다.That is, the refrigerant flow rate correcting unit 74 receives the current temperature of LNG flowing through the supply line L1 from the temperature controller 65 and corrects the refrigerant flow rate value received from the refrigerant flow rate calculating unit 72 based on this. do.

예컨대 냉매유량보정부(74)는 공급라인(L1)을 통해 흐르는 LNG의 현재 온도가 LNG 스펙(specification) -155℃ 보다 1℃가 미달된 -154℃일 경우 LNG 현재 유량값 ‘5.5’에 1% 의 추가 유량을 더하라는 미리 설정된 수식에 따라 ‘5.555’로 보정할 수 있다. 이러한 미리 설정된 수식은 사전에 산출되거나 실험값으로 정해질 수 있다.For example, when the current temperature of the LNG flowing through the supply line L1 is -154°C, which is 1°C lower than the LNG specification -155°C, the refrigerant flow rate correction unit 74 sets the current flow rate of 1 to '5.5'. It can be calibrated to '5.555' according to the preset formula to add an additional flow rate of %. Such a preset formula may be calculated in advance or determined as an experimental value.

LNG유량산출부(92)는 제2산출부(80)에 의해 산출된 냉매의 현재 유량값을 미리 설정된 수식에 대입하여 LNG 유량값을 산출한다. 제2산출부(80)에 의해 산출된 냉매의 현재 유량값은 냉매유량제어기(50)에 의해 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절됨에 따라 변경되는 현재 냉매 유량값이다. LNG유량산출부(92)는 예컨대 냉매와 LNG의 유량비가 1:1로 설정된 경우 냉매 유량값에 따라 LNG 유량값을 동일 값으로 산출할 수 있다. 냉매와 LNG의 유량비는 미리 산출된 값이거나 실험으로 결정한 값일 수 있다.The LNG flow rate calculation unit 92 calculates the LNG flow rate value by substituting the current flow rate value of the refrigerant calculated by the second calculation unit 80 into a preset equation. The current flow rate value of the refrigerant calculated by the second calculation unit 80 is a current refrigerant flow rate value that is changed as the flow rate of the refrigerant expanded by the expander 13 is adjusted by the refrigerant flow controller 50 . The LNG flow rate calculating unit 92 may calculate the LNG flow rate as the same value according to the refrigerant flow rate value when, for example, the flow ratio of the refrigerant and the LNG is set to 1:1. The flow ratio between the refrigerant and the LNG may be a value calculated in advance or a value determined by an experiment.

LNG유량보정부(94)는 공급라인(L1)을 통해 흐르는 LNG의 온도값을 기초로 LNG유량산출부(92)에 의해 산출된 LNG 유량값을 보정한다. LNG유량보정부(94)는 상술한 냉매유량보정부(74)와 마찬가지로 미리 설정된 수식에 따라 LNG유량산출부(92)에 의해 산출된 LNG 유량값을 보정할 수 있다. LNG유량산출부(92)와 LNG유량보정부(94)는 다른 예에서 생략될 수 있다.The LNG flow rate correction unit 94 corrects the LNG flow rate value calculated by the LNG flow rate calculation unit 92 based on the temperature value of the LNG flowing through the supply line L1. The LNG flow rate correcting unit 94 may correct the LNG flow rate value calculated by the LNG flow rate calculating unit 92 according to a preset equation, similarly to the above-described refrigerant flow rate correcting unit 74 . The LNG flow rate calculating unit 92 and the LNG flow rate correcting unit 94 may be omitted in other examples.

이와 같이 LNG 및 냉매의 유량 변경 시 LNG 온도의 응답 속도가 지연되는데 이를 보정하기 위해 LNG 온도를 보정값으로 이용한다. 이때 보정된 유량값을 통해 급격한 유량 변화가 일어나지 않도록 천천히 유량을 늘려간다.As described above, when the flow rate of LNG and refrigerant is changed, the response speed of the LNG temperature is delayed. In order to correct this, the LNG temperature is used as a correction value. At this time, the flow rate is increased slowly to prevent a sudden change in flow rate through the corrected flow rate value.

상술한 하이셀렉터(20)는 LNG유량보정부(94)로부터 보정된 LNG 유량값을 수신한 경우, 보정된 LNG 유량값을 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 높은 값을 선택하게 된다.When the above-described high selector 20 receives the corrected LNG flow rate value from the LNG flow rate correction unit 94, the high selector 20 compares the corrected LNG flow rate value with the LNG flow rate input for increasing the LNG flow rate to select a higher value. do.

한편, LNG 유량 감소를 수행할 경우, 로우셀렉터(40)는 LNG 유량 감소를 위해 입력된 LNG 유량값(예컨대, ‘4’)과 미리 설정된 냉매 유량값 ‘5’를 비교하여 낮은 값을 선택한다.Meanwhile, when reducing the LNG flow rate, the row selector 40 compares the LNG flow rate value (eg, '4') input for reducing the LNG flow rate with a preset refrigerant flow rate value '5' and selects a lower value. .

다음으로, 냉매유량산출부(72)는 로우셀렉터(40)에 의해 선택된 유량값을 미리 설정된 수식에 대입하여 냉매 유량값을 산출하고, 냉매유량보정부(74)는 공급라인(L1)을 통해 흐르는 LNG의 온도값을 기초로 냉매유량산출부(72)에 의해 산출된 냉매 유량값을 보정한다.Next, the refrigerant flow rate calculation unit 72 calculates a refrigerant flow rate value by substituting the flow rate value selected by the row selector 40 into a preset formula, and the refrigerant flow rate correcting unit 74 through the supply line L1 The refrigerant flow rate value calculated by the refrigerant flow rate calculating unit 72 is corrected based on the temperature value of the flowing LNG.

다음으로, 냉매유량제어기(50)는 보정된 냉매 유량값에 따라 팽창기(13)에 의해 팽창되는 냉매의 유량을 조절한다.Next, the refrigerant flow controller 50 adjusts the flow rate of the refrigerant expanded by the expander 13 according to the corrected refrigerant flow rate value.

다음으로, LNG유량산출부(92)는 냉매유량제어기(50)의 제어에 따라 점차적으로 감소하는 팽창기(13)에 의해 팽창되는 냉매의 현재 유량값을 입력받아 미리 설정된 수식에 대입하여 LNG 유량값을 산출한다.Next, the LNG flow rate calculation unit 92 receives the current flow rate value of the refrigerant expanded by the expander 13, which is gradually reduced according to the control of the refrigerant flow rate controller 50, and substitutes it into a preset formula to enter the LNG flow rate value. to calculate

다음으로, LNG유량보정부(94)는 공급라인(L1)을 통해 흐르는 LNG의 온도값을 기초로 LNG유량산출부(92)에 의해 산출된 LNG 유량값을 보정한다.Next, the LNG flow rate correction unit 94 corrects the LNG flow rate value calculated by the LNG flow rate calculation unit 92 based on the temperature value of the LNG flowing through the supply line L1 .

다음으로, 하이셀렉터(20)는 LNG 유량 감소를 위해 입력된 LNG 유량값과 LNG유량보정부(94)에 의해 보정된 LNG 유량값 중 높은 값을 선택한다.Next, the high selector 20 selects a higher value among the input LNG flow rate value for reducing the LNG flow rate and the LNG flow rate value corrected by the LNG flow rate correction unit 94 .

LNG유량제어기(30)는 하이셀렉터(20)에 의해 선택된 LNG 유량값을 기초로 공급라인(L1)에 마련된 LNG 유량밸브(V1)를 조절한다.The LNG flow controller 30 controls the LNG flow valve V1 provided in the supply line L1 based on the LNG flow rate value selected by the high selector 20 .

이상에서는 특정의 실시 예에 대하여 도시하고 설명하였다. 그러나, 본 발명은 상기한 실시 예에만 한정되지 않으며, 발명이 속하는 기술분야에서 통상의 지식을 가진 자라면 이하의 청구범위에 기재된 발명의 기술적 사상의 요지를 벗어남이 없이 얼마든지 다양하게 변경 실시할 수 있을 것이다.In the above, specific embodiments have been shown and described. However, the present invention is not limited to the above-described embodiments, and those of ordinary skill in the art to which the invention pertains can make various changes without departing from the spirit of the invention as set forth in the claims below. will be able

10: 열교환기 13: 팽창기
15: 저장탱크 20: 하이셀렉터
30: LNG유량제어기 40: 로우셀렉터
50: 냉매유량제어기 60: 제1산출부
72: 냉매유량산출부 74: 냉매유량보정부
80: 제2산출부 92: LNG유량산출부
94: LNG유량보정부10: heat exchanger 13: expander
15: storage tank 20: high selector
30: LNG flow controller 40: low selector
50: refrigerant flow controller 60: first output unit
72: refrigerant flow rate calculation unit 74: refrigerant flow rate correction unit
80: second calculation unit 92: LNG flow rate calculation unit
94: LNG flow correction unit

Claims (5)

압축기, 냉각기 및 팽창기에 의해 압축, 냉각 및 팽창이 이루어진 냉매와 천연가스 간 열교환을 수행하여 LNG를 생성하고, 상기 LNG를 저장하는 저장탱크와 공급라인을 통해 연결된 열교환기;
상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 미리 설정된 LNG 유량값을 비교하여 높은 값을 선택하는 하이셀렉터;
상기 하이셀렉터에 의해 선택된 LNG 유량값을 기초로 상기 공급라인에 마련된 LNG 유량밸브를 조절하는 LNG유량제어기;
상기 하이셀렉터에 의해 선택된 LNG 유량값에 따라 점차적으로 증가하는 LNG의 현재 유량값을 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택하는 로우셀렉터; 및
상기 로우셀렉터에 의해 선택된 LNG 유량값을 기초로 상기 팽창기에 의해 팽창되는 냉매의 유량을 조절하는 냉매유량제어기;를 포함하는 LNG 액화용 유량 조절 시스템.a heat exchanger connected through a supply line to a storage tank that generates LNG by performing heat exchange between a refrigerant compressed, cooled, and expanded by a compressor, a cooler and an expander and natural gas;
a high selector for selecting a high value by comparing an input LNG flow rate value and a preset LNG flow rate value for increasing the LNG flow rate;
an LNG flow controller that adjusts the LNG flow valve provided in the supply line based on the LNG flow rate value selected by the high selector;
a low selector which compares a current flow rate value of LNG, which is gradually increased according to the LNG flow rate value selected by the high selector, with an LNG flow rate value input for increasing the LNG flow rate, and selects a lower value from the two; and
The flow rate control system for LNG liquefaction comprising a; a refrigerant flow controller that adjusts the flow rate of the refrigerant expanded by the expander based on the LNG flow rate value selected by the row selector. 제1항에 있어서,
상기 공급라인을 통해 흐르는 LNG의 유량을 측정하는 제1측정기와,
상기 LNG의 압력을 측정하는 제2측정기와,
상기 LNG의 온도를 측정하는 제3측정기와,
상기 측정된 LNG의 유량, 압력, 온도 값을 기초로 상기 공급라인을 통해 흐르는 LNG의 현재 유량값을 산출하는 제1산출부를 더 포함하되,
상기 LNG유량제어기는 상기 제1산출부에 의해 산출된 LNG의 현재 유량값을 고려하여 상기 하이셀렉터에 의해 선택된 LNG 유량값에 도달하도록 상기 공급라인에 마련된 LNG 유량밸브를 조절하고,
상기 로우셀렉터는 상기 제1산출부에 의해 산출된 LNG의 현재 유량값을 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 둘 중에서 낮은 값을 선택하는 것인 LNG 액화용 유량 조절 시스템.The method of claim 1,
a first measuring device for measuring the flow rate of LNG flowing through the supply line;
a second measuring device for measuring the pressure of the LNG;
a third measuring device for measuring the temperature of the LNG;
Further comprising a first calculation unit for calculating a current flow rate value of the LNG flowing through the supply line based on the measured flow rate, pressure, and temperature values of the LNG,
The LNG flow controller adjusts the LNG flow valve provided in the supply line to reach the LNG flow rate value selected by the high selector in consideration of the current flow rate value of LNG calculated by the first calculation unit,
The low selector compares the current flow rate value of LNG calculated by the first calculation unit with the LNG flow rate value input to increase the LNG flow rate and selects a lower value from the two. 제1항에 있어서,
상기 로우셀렉터에 의해 선택된 LNG 유량값을 미리 설정된 수식에 대입하여 냉매 유량값을 산출하는 냉매유량산출부와,
상기 공급라인을 통해 흐르는 LNG의 온도값을 기초로 상기 냉매유량산출부에 의해 산출된 냉매 유량값을 보정하는 냉매유량보정부를 더 포함하되,
상기 냉매유량제어기는 상기 보정된 냉매 유량값을 수신한 경우, 상기 보정된 냉매 유량값에 따라 상기 팽창기에 의해 팽창되는 냉매의 유량을 조절하는 LNG 액화용 유량 조절 시스템.The method of claim 1,
a refrigerant flow rate calculation unit for calculating a refrigerant flow rate value by substituting the LNG flow rate value selected by the row selector into a preset equation;
Further comprising a refrigerant flow rate correction unit for correcting the refrigerant flow rate value calculated by the refrigerant flow rate calculating unit based on the temperature value of the LNG flowing through the supply line,
When the refrigerant flow controller receives the corrected refrigerant flow rate value, the flow rate control system for LNG liquefaction adjusts the flow rate of the refrigerant expanded by the expander according to the corrected refrigerant flow rate value. 제3항에 있어서,
상기 냉각기를 거쳐 상기 팽창기로 흐르는 냉매의 유량을 측정하는 제4측정기와,
상기 냉매의 압력을 측정하는 제5측정기와,
상기 냉매의 온도를 측정하는 제6측정기와,
상기 측정된 냉매의 유량, 압력, 온도 값을 기초로 냉매의 현재 유량값을 산출하는 제2산출부를 더 포함하되,
상기 냉매유량제어기는 상기 제2산출부에 의해 산출된 냉매의 현재 유량값을 고려하여 상기 냉매유량보정부에 의해 보정된 냉매 유량값에 따라 상기 팽창기에 의해 팽창되는 냉매의 유량을 조절하는 LNG 액화용 유량 조절 시스템.4. The method of claim 3,
a fourth measuring device for measuring the flow rate of the refrigerant flowing through the cooler to the expander;
a fifth measuring device for measuring the pressure of the refrigerant;
A sixth measuring instrument for measuring the temperature of the refrigerant;
Further comprising a second calculation unit for calculating the current flow rate value of the refrigerant based on the measured flow rate, pressure, and temperature values of the refrigerant,
The refrigerant flow controller controls the flow rate of the refrigerant expanded by the expander according to the refrigerant flow rate value corrected by the refrigerant flow rate correcting unit in consideration of the current flow rate value of the refrigerant calculated by the second calculating unit. for flow control systems. 제4항에 있어서,
상기 산출된 냉매의 현재 유량값을 미리 설정된 수식에 대입하여 LNG 유량값을 산출하는 LNG유량산출부와,
상기 공급라인을 통해 흐르는 LNG의 온도값을 기초로 상기 LNG유량산출부에 의해 산출된 LNG 유량값을 보정하는 LNG유량보정부를 더 포함하되,
상기 하이셀렉터는 상기 보정된 LNG 유량값을 수신한 경우, 상기 보정된 LNG 유량값을 상기 LNG 유량 증가를 위해 입력된 LNG 유량값과 비교하여 높은 값을 선택하는 LNG 액화용 유량 조절 시스템.
5. The method of claim 4,
an LNG flow rate calculation unit for calculating an LNG flow rate value by substituting the calculated current flow rate value of the refrigerant into a preset equation;
Further comprising an LNG flow rate correction unit for correcting the LNG flow rate value calculated by the LNG flow rate calculating unit based on the temperature value of the LNG flowing through the supply line,
When the high selector receives the corrected LNG flow rate value, the high selector compares the corrected LNG flow rate value with the LNG flow rate value input for increasing the LNG flow rate to select a high value.
KR1020200107819A 2020-08-26 2020-08-26 Flow control system used for liquefaction of lng KR20220027336A (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120005158A (en) 2010-07-08 2012-01-16 대우조선해양 주식회사 Method and apparatus for liquefying natural gas

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120005158A (en) 2010-07-08 2012-01-16 대우조선해양 주식회사 Method and apparatus for liquefying natural gas

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