• 센서학회지
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• 제27권5호
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• pp.352-356
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• 2018

This paper relates to a technology for monitoring a liquefied gas storage tank in the special gas field where demand is increasing owing to the continuous growth of related fields such as the semiconductor, display, and ICT convergence electronics industries. We have proposed a system for real - time monitoring using wireless sensor network technology, and implemented a system consisting of a sensor unit, transmitter module, and receiver module to be attached to a liquefied gas storage tank. The system was applied to LCO2 tanks among various liquefied gas storage tanks to verify the feasibility. The storage tanks employed in the experiments has capacities of 16,179 l and was 1,920 mm in inner diameter. Furthermore, the density was 1.03 g/l. The measured data were compared with reference data on the remaining gas level versus the $CO_2$ height of the surface, expressed using a conventional water meter, provided by an existing storage tank supplier. The experimental results show that the data is similar to the standard data provided by the tank supplier, and has a high accuracy and reliability within an error range of 0.03%.

• 해양환경안전학회지
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• 제15권3호
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• pp.269-274
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• 2009

LNGC(Liquefied Natural Gas Carrier)의 역사는 1959년 $5,000m^3$ 급 LNG선 "Methane Pioneer"호를 시작으로 1969년에는 $71,500m^3$ 급, 1973년에는 Moss Type의 최초 LNG운반선 "Norman Lady($87,600m^3$)호, 1980년대 $125,000m^3$ 급을 시작으로 1990년대를 거처 $135,000m^3$ 급, 2007년 $210,000m^3$급 그리고 2008년에는 $266,000m^3$ 급의 초대형 액화천연가스 운반선이 출현하였다. 또한 2006년 11월에는 기존 내 외연 기관이 아닌 발전기 기동으로 Propeller를 움직이는 DFDE(Duel Fuel Diesel Electric)엔진, 육상의 Storage Tank를 생략한 기화설비를 갖춘 LNG-RV(Re-gasification Vessel)와 주 기관은 Slow Diesel을 택하고, 운항 중 발생하는 BOG(Boil Off Gas)를 재액화시키는 설비를 갖춘 DRL(Diesel Re-Liquefaction)선박 및 해상 LNG 생산 저장시설인 LNG-FPSO(Floating Production and Storage Offshore), 그리 고 해상 LNG 인수기지 역할을 하는 LNG-FSRU(Floating Store and Re-gasification Unit) 등이 개발되었다. 이 논문에서는 LNG Project, 전 세계 에너지 시장과 LNGC의 발전 추세에 대하여 다루었다.

• 한국가스학회지
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• 제24권1호
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• pp.10-16
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• 2020

액화석유가스의 안전관리 및 사업법에서 판매사업자의 벌크로리를 이용한 LPG 공급은 10톤 이하의 벌크로리로 3톤 미만의 소형저장탱크까지만 가능하다. 정부에서는 LPG 판매사업자의 향상된 안전관리능력을 반영하여 벌크로리의 공급 범위를 10톤 미만의 저장탱크까지로 확대할 계획을 발표하였다. 따라서 벌크로리를 통해 안정적으로 저장탱크에 LPG를 공급하기 위해서는 기존 벌크로리의 LPG 공급 시스템에 대한 기술적 평가가 필요하다. 본 연구에서는 벌크로리를 통한 국내의 LPG 공급시스템 현황을 파악하고, 안전한 LPG 공급방법에 대해서 알아보고자 한다. 우선, 기초자료 수집을 위해서 관련 사업자 대상으로 벌크로리를 통한 저장탱크 LPG 공급시스템에 대한 설문조사를 실시하였다. 설문 조사 결과를 바탕으로 현장조사를 진행하여 안정적인 LPG공급을 위한 기초자료를 마련하고자 한다.

• 한국산업융합학회 논문집
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• 제23권5호
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• pp.727-733
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• 2020

Recently, reciprocating cryogenic pumps are mainly developed for small-and-mid sized fuel supply systems. Centrifugal type pumps are not actively developed. Most cryogenic submerged pumps are imported. For transportation, cryogenic liquefied natural gas requires the liquid pump technology that can works in extreme evironments. In order to transport liquefied natural gas, it is necessary to apply pump technology. This is the fundamental research for developing the submerged pump technology applicable to the transportation and storage system equipment of cryogenic liquefied system. It tries to secure basic design materials through reverse-engineering in the cryogenic submerged pump development. Regarding materials, STS-304 and STS-431 which are stainless materials widely used in the cryogenic area are applied. Aluminum alloy is applied to impeller and upper manifolder and the pump rotates at the high speed of 6,000rpm.

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.65-69
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• 2023

Hydrogen is an eco-friendly energy source and is being actively researched in various fields around the world, including mobility and aerospace. In order to effectively utilize hydrogen energy, it should be used in a liquid state with high energy storage density, but when hydrogen is stored in a liquid state, BOG (boil-off gas) is generated due to the temperature difference with the atmosphere. This should be re-condensed when considering storage efficiency and economy. In particular, large-capacity liquid hydrogen storage tank is required a gaseous helium circulation cooling system that cools by circulating cryogenic refrigerant due to the increase in heat intrusion from external air as the heat transfer area increases and the wide distribution of the gas layer inside the tank. In order to effectively apply the system, thermo-hydraulic analysis through process analysis is required. In this study, the condenser design and system characteristics of a gaseous helium circulation cooling system for BOG recondensation of a liquefied hydrogen storage tank were compared.

• 한국가스학회지
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• 제7권4호
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• pp.36-43
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• 2003

본 논문에서는 LNG 냉열 에너지를 활용한 지역 냉방 시스템 가능성에 대해 고찰하고자 한다. 액상의 LNG는 기상의 가스로 변환하는 과정에서 많은 냉열 에너지를 발생한다. 최근에 빙축열을 이용한 건물의 냉방 시스템 구축과 심층수를 이용한 지역 냉방 시스템이 도심지의 기존 사무실 건물이나 대규모 건물의 냉방장치로 도입되고 있는 상황이다. LNG의 냉열 에너지는 기존의 냉매에 의존한 개별 냉방 시스템을 대체하는 새로운 냉열 에너지 공정으로 쾌적한 공간을 제공하는 천연의 대규모 냉각매체로 재사용될 수 있다. 버려지는 냉열 에너지는 낮은 코스트로 운영될 수 있는 중요한 청정 에너지원이기 때문에 냉방 시스템으로 개발되면, 기존의 에어콘 시스템에 견주어 볼 때 공기중에 유해한 오염원의 발생과 환경적으로 유해한 냉매 방출을 대폭적으로 줄일 수 있는 우수한 냉방 시스템이 될 것이다. 따라서, 본 연구에서는 냉열 에너지를 활용한 지역 냉방 시스템에 대한 환경 친화적 기본적 설계 개념, 여러 가지 냉방 시스템 성능에 대한 유익한 기반적 정보를 제공하고자 한다.

• 한국가스학회지
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• 제7권3호
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• pp.13-17
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• 2003

LNG 저장탱크의 주요 구조인 멤브레인은 LNG 누설을 방지하기 위하여 설계되었다. 멤브레인 유닛은 $-162^{\circ}C$의 액화시킨 LNG의 접촉에 따라 발생하는 가스압, 액압, 그리고 열하중을 지지하도록 설계되므로 멤브레인 구조의 강도를 실험적 방법을 이용하여 측정하는 것이 매우 중요하다. 본 논문에서는 상용 전기저항식 스트레인 게이지와 자체적으로 제작한 기계적 열 변형 측정 장치를 이용한 변형 측정 시스템을 제안하였다.

• 한국해양공학회지
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• 제33권5호
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• pp.394-399
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• 2019

Plywood is a laminated wood material where alternating layers are perpendicular to each other. It is used in a liquefied natural gas (LNG) carrier for an insulation system because it has excellent durability, a light weight, and high stiffness. An LNG cargo containment system (LNG CCS) is subjected to loads from gravity, sloshing impact, hydrostatic pressure, and thermal expansion. Shear forces are applied to an LNG CCS locally by these loads. For these reasons, the materials in an LNG CCS must have good mechanical performance. This study evaluated the shear behavior of plywood. This evaluation was conducted from room temperature ($25^{\circ}C$) to cryogenic temperature ($-163^{\circ}C$), which is the actual operating environment of an LNG storage tank. Based on the plywood used in an LNG storage tank, a shear test was conducted on specimens with thicknesses of 9 mm and 12 mm. Analyses were performed on how the temperature and thickness of the plywood affected the shear strength. Regardless of the thickness, the strength increased as the temperature decreased. The 9 mm thick plywood had greater strength than the 12 mm thick specimen, and this tendency became clearer as the temperature decreased.

• 해양환경안전학회지
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• 제24권3호
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• pp.352-359
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• 2018

As a fuel for ship propulsion, liquefied natural gas (LNG) is currently considered a proven and reasonable solution for meeting the IMO emission regulations, with gas engines for the LNG-fueled ship covering a broad range of power outputs. For an LNG-fueled ship, the LNG bunkering process is different from the HFO bunkering process, in the sense that the cryogenic liquid transfer generates a considerable amount of boil-off gas (BOG). This study investigated the effect of the temperature difference on boil-off gas (BOG) production during ship-to-ship (STS) LNG bunkering to the receiving tank of the LNG-fueled ship. A concept design was resumed for the cargo/fuel tanks in the LNG bunkering vessel and the receiving vessel, as well as for LNG handling systems. Subsequently, the storage tank capacities of the LNG were $4,500m^3$ for the bunkering vessel and $700m^3$ for the receiving vessel. Process dynamic simulations by Aspen HYSYS were performed under several bunkering scenarios, which demonstrated that the boil-off gas and resulting pressure buildup in the receiving vessel were mainly determined by the temperature difference between bunkering and the receiving tank, pressure of the receiving tank, and amount of remaining LNG.

• Journal of Advanced Research in Ocean Engineering
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• 제3권3호
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• pp.125-135
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• 2017

The paper considers the practical application of the FMEA(Failure Mode and Effect Analysis) method to assess the operational reliability of the LNG(Liquefied Natural Gas) transfer system, which is a potential problem for the connection between the LNG FPSO and LNG carrier. Hazard Identification (HAZID) and Hazard operability (HAZOP) are applied to identify the risks and hazards during the operation of LNG transfer system. The approach is performed for the FMEA to assess the reliability based on the detection of defects typical to LNG transfer system. FTA and FMEA associated with a probabilistic risk database to the operation scenarios are applied to assess the risk. After providing an outline of the safety assessment procedure for the operational problems of system, safety assessment example is presented, providing details on the fault tree of operational accident, safety assessment, and risk measures.