• Journal of the Korean Institute of Gas
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• v.5 no.2 s.14
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• pp.52-61
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• 2001

Cryogenic LNG(Liquefied Natural Gas) which is stored in the cylindrical storage tanks of $100,000m^3$ has very complex flow phenomena and the changes of thermal properties with exterior conditions and operation modes. These complex thermofluid behaviors are affected by the storage, exterior conditions of LNG, design specifications and heat transfer characteristics of tanks. Also, those have influence on the stable storage and supply of LNG in the storage tanks. Thus this study peformed the analysis on the 2-D heat transfer of the tank with exterior conditions, on the Cool Down Process in order to cool down the LNG Storage Tank at the initial normal state, and on the Filling Process considered for incoming and rising of LNG. The analysis on the Mixing LNG Storage was studied too. At last, the visualized program on the complex thermofluidodynamic analysis was developed on the basis of the above analyses. The development of this program becomes to be used to the basic design of the commercial tanks as well as to assure technical skill of the analysis on the thermal stability of the stored LNG in the LNG Storage Tank.

• Journal of the Korean Institute of Gas
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• v.5 no.3 s.15
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• pp.23-28
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• 2001

BOG(Boil Off Gas) is formed about 0.05 vol$\%$/day from LNG tanks of LNG receiving terminal. To recycle the BOG using LNG cold energy, the quantities of LNG and BOG is mixed at the ratio of 11 : 1 by mass in the recondenser of mixing drum type. However, this process is inefficient in the view of energy. It is the most necessary for improvement BOG recondensing process to reduce LNG quantities supplying to recondense system. Therefore, this study has aimed to propose heat exchanger type and suggest results through the analysis of ASPEN PLUS simulator and feasibility study.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.683-688
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• 2001

Cryogenic LNG(Liquefied Natural Gas) which is stored in the cylindrical storage tanks of $100,000m^{3}$ has very complex flow phenomena and the changes of thermal properties with exterior conditions and operation mdoes. These complex thermofluid behaviors are affected by the storage, exterior conditions of LNG, design specifications and heat transfer characteristics of tanks, Also, those have influence on the stable storage and supply of LNG in the storage tanks. Thus this study performed the analysis on the 2-D heat transfer of the tank with exterior conditions, on the Cool Down Process in order to cool down the LNG Storage Tank at the initial normal state, and on the Filling Process considered for incoming and rising of LNG. The analysis on the Mixing LNG Storage was studied too. At last, the visualized program on the complex thermofluidodynamic analysis was developed on the basis of the above analyses. The development of this program becomes to be used to the basic design of the commercial tanks as well as to assure technical skill of the analysis on the thermal stability of the stored LNG in the LNG Storage Tank.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.240-245
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• 2013

The optimum binder ratio of the low heat mass concrete for LNG tank was evaluated in the present study. Three types of binder such as OPC I, ground granulated blast-furnace slag powder were mixed and were used. Also fine particle cement and activator were used to raise an early age strength development and ground limestone was used to reduce the cost. As a result of the study, mix ratio II (30:30:40) was suitable for Bottom Center and mix ratio III(40:30:30) was suitable for Roof based on compressive strength and semi-adiabatic temperature.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.273-278
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• 1998

여러가지 연소특성들은 가연성물질의 취급함에 있어 밸브조작실수, 배관접합부 파손. 저장 및 수송의 부주의로 주위에 공기와 혼합되면 화재 및 폭발이 발생할 수 있는 잠재적 위험성을 평가할 수 있다. 여러 연소특성 가운데 폭발(연소)한계(explosive (flammable) limits)는 가연성물질(가스 및 증기)을 다루는 화학공정에 있어 설계시 고려해야 할 가장 중요한 변수로써, 발화원이 존재할 때 가연성가스와 공기가 혼합하여 일정 농도 범위내에서만 연소가 이루어지는 혼합범위를 말한다. (중략)

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.174-179
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• 2016

To protect the ocean environment, the use of liquefied natural gas (LNG) carriers, bunkering ships, and fueled ships is increasing. Recently, Korean shipbuilders have developed and supplied a partial reliquefaction facility for boil-off-gas (BOG). Despite reasonable insulation, heat leakage in vessel storage tanks causes LNG to be continuously evaporated as BOG. This research analyzed the maximum liquid yield rate for various partial reliquefaction systems (PRS) and considered related factors affecting yields. The results showed a liquid yield of 48.7% from an indirect PRS system (heat exchanges between cold flash gas and compressed natural gas), and 41% from a direct PRS system (BOG is mixed with flash gas and discharged from a liquid-vapor separator). The primary factor affecting liquid yield was heat exchanger effectiveness; the exchanger's efficiency and insulation characteristics directly affect the performance of BOG reliquefaction systems.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.33-44
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• 2012

In this study, the optimal operating conditions for the dual mixed refrigerant(DMR) cycle were determined by considering the power efficiency. The DMR cycle consists of compressors, heat exchangers, seawater coolers, valves, phase separators, tees, and common headers, and the operating conditions include the equipment's flow rate, pressure, temperature, and refrigerant composition per flow. First, a mathematical model of the DMR cycle was formulated in this study by referring to the results of a past study that formulated a mathematical model of the single mixed refrigerant(SMR) cycle, which consists of compressors, heat exchangers, seawater coolers, and valves, and by considering as well the tees, phase separators, and common headers. Finally, in this study, the optimal operating conditions from the formulated mathematical model was obtained using a hybrid optimization method that consists of the genetic algorithm(GA) and sequential quadratic programming(SQP). Moreover, the required power at the obtained conditions was decreased by 1.4% compared with the corresponding value from the past relevant study of Venkatarathnam.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.177-187
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• 1998

최근 국내에서 해양 구조물, 장대 교량의 하부구조물, LNG저장탱크 등 매스콘크리트의 증가추세에 따라 구조물의 고내구성과 관련하여 시멘트의수화열에 의한 온도균열의 발생을 최소화 시킬 수 있는 3성분계 혼합형 저발열시멘트가 개발되어 실 구조물의 적용단계에 있으나, 저발열시멘트가 개발되어 실 구조물의 적용단계에 있으나 저발열시멘트의 특성에 대한 전반적인 연구보고가 국내에서는 미진한 실정이다. 따라서 본 연구에서는 3성분계 혼합형 저발열시멘트의 특성 및 코\ulcorner리트의기초물성을 1종 보통포틀랜트 시멘트, 5종 내황산염시멘트, 슬래그시멘트와 비교하였다. 글 결과 저발열 콘크리트의 찹축강도는 초기재령에서 강도발현률이 적은 반면 장기강도발현률은 상당히 큰 경향을 보였다. 또한 수화열은 1종시멘트를 사용한 콘크리트에 비하여 1/3~1/2정도로 매스콘크리트의 수화열을 대폭적으로 저감시킬 수 있을 뿐만 아니라 염소이온에 대한 저항성이 상대적으로 높게 나타나 거대 해양 구조물의 적용에 매우 유리한 시멘트로 판단되었다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.145.2-145.2
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• 2011

메탄 하이드레이트는 낮은 온도와 높은 압력 조건에서 물분자들의 격자구조에 메탄가스분자가 포획되어 수소결합으로 형성되는 외관상 얼음과 비슷한 결정성 화합물이다. $1m^3$의 메탄 하이드레이트는 표준상태에서 $172m^3$의 메탄가스와 $0.8m^3$의 물로 분해되며, $-10^{\circ}C{\sim}-20^{\circ}C$의 온도에서는 하이드레이트 입자표면에서 생성되는 얼음막으로 인하여 상압에서도 안정하게 존재하는 자기보존 효과를 가지고 있다. 따라서 이와 같은 특징을 천연가스 수송 및 저장의 방법으로 이용할 경우 $-162^{\circ}C$의 초저온을 만들고 유지시키기 위하여 고가의 설비를 필요로 하는 기존의 LNG 수송방법을 대체할 수 있다. 특히 연간 천연가스 소비량을 0.4 ~ 1.0 million ton으로 가정했을 때, 하이드레이트 수송방법은 LNG 수송에 비해 18 ~ 25% 정도의 비용을 절약할 수 있는 경제적인 방법으로 알려져 있다. 그러나 하이드레이트를 인공적으로 제조할 경우 물분자와 가스분자의 반응율이 낮기 때문에 하이드레이트가 생성되기까지 많은 시간이 소요되며, 하이드레이트에 포획되는 가스분자의 양도 적다. 따라서 본 연구에서는 이와 같은 문제점을 해결하기 위하여 다공성 물질인 천연 제올라이트와 제올라이트 13X를 이용하여 제올라이트 혼합유체를 제조하였으며, 메탄가스와 반응시켜 하이드레이트를 생성시키는 실험을 수행하였다. 그 결과, 하이드레이트 생성 시 천연 제올라이트와 제올라이트 13X 모두 0.01 wt%의 혼합비율에서 가장 좋은 효과를 나타내었으며, 하이드레이트에 포획된 가스의 양은 같은 과냉도 조건에서 천연제올라이트와 제올라이트 13X 혼합유체를 이용하여 하이드레이트를 생성 시켰을 때, 증류수보다 각각 4배, 5배 높음을 보였다. 또한 낮은 과냉도에서 하이드레이트 생성 시 제올라이트, 제올라이트13X 혼합유체에서 하이드레이트 생성시간이 증류수에서 하이드레이트를 생성시킬 때보다 빨라짐을 확인하였다.

• Plant Journal
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• v.9 no.3
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• pp.38-42
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• 2013

Submarine gas fields have focused because of the increasing fuel cost, the environmental regulations, and the safety & NIMBY problems. LNG-FPSO which is available for acid gas removal, recovery of the condensate & LPG and Liquefaction in topside process is one of high technology offshore structures. On the other hands, it is necessary to verify the pre-treatment efficiency by the ship motion and to apply to the design for LNG-FPSO. This study is to develop the pre-treatment technology for LNG-FPSO as taking account to the process efficiency by ship motion effects and the area optimization. Based on the simulation results, it founds that hybrid process shows the low circulate rate, the low heat duty and the small size of column dimensions compared to typical amine process. It will be verified the process efficiency in the various conditions by sea states as performing the 6-DOF motion test and CFD simulation.