• Title/Summary/Keyword: LNG carrier

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Development of the Automatic Design Program for Scaffolding System of the Membrane LNG Carrier (멤브레인 LNG 운반선용 스카폴딩 시스템의 자동 설계 프로그램 개발)

  • Lee, Hee-Tae;Shin, Sang-Beom;Park, Yun-Ki
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.2
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    • pp.233-241
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    • 2010
  • Scaffolding system in the membrane LNG carrier is a steel structure composed of various pipe-shaped members connected by specific coupling devices. In this study, the automatic design program for scaffolding system in membrane LNG carrier has been developed. It enables user to arrange members easily considering design constraints and input variables such as size of tank, position of legs, level height and so on. In addition to that, it creates finite element analysis model with loading and boundary conditions automatically and carries out structural analysis. With post processor based a state-of-the-art computer graphics, users can easily check the results of structural analysis and make a report for structural safety of scaffolding system.

Heat Transfer Analysis and BOG Estimation of Membrane-Type LNG Cargo during Laden Voyage (멤브레인형 LNG선 Cargo의 만선항해시 열전달 해석 및 BOG 평가)

  • Heo, Jin-Uk;Lee, Young-Ju;Cho, Jin-Rae;Ha, Mun-Keun;Lee, Joong-Nam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.3
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    • pp.393-400
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    • 2003
  • Excessive generation of BOG during the LNG transportation not only causes the severe financial loss but also leads to the unexpected disaster. Therefore, the carrier cargo insulating interior LNG should be carefully designed based upon an accurate heat transfer analysis. However. it is not simple to analyze heat transfer of LNG cargo, because it is in a complex insulation structure and LNG carrier experiences a complicated heat transfer according to various kinds of voyage conditions. In this paper, we carried out the transient finite element heat transfer analysis for a cargo of Mark-111 membrane-type LNG carrier during laden voyage, and we compared heat transfer rates between considering natural convection and considering conduction. For this goal, we developed a PCL program incorporating with a commercial MSC/NASTRAN FEM code.

A Study on the Three-Dimensional Steady State Temperature Distributions and BOR Calculation Program Development for the Membrane Type LNG Carrier (Membrane Type LNG선의 3차원 정상상태 온도분포 및 BOR 계산 프로그램 개발에 관한 연구)

  • 이정혜
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.2
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    • pp.140-149
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    • 1999
  • This study is on the development of the computer program that calculates a 3-D hull temperadistribution and analyzes BOR(Boil off rate) to be important to the heat design of a membrane type LNG carrier. The quarter of a tank is taken as an calculation model. And the thermal conductivity of insulation is assumed to be the function of a temperature. In the present steady state calculation, the temperature of LNG in a cargo tank is assumed to be -$162^{\circ}C$ and the air temperature of a cofferdam, to be +$5^{\circ}C$. The lowest air temperature in compartments is calculated as $21.39^{\circ}C$ under the USCG condition ($T_{air}=-18^{\circ}C,\;T_{sw}=O^{\circ}C)$ and B.O.R value is O.0977%/day under the maximum boil-off condition, IMO IGC ($T_{air}=45^{\circ}C,\;T_{sw}=32^{\circ}C$), which satisfies the requirement by KOGAS. The calculated temperature distribution over tank panels at each condition is maximum 3% less than GTT's results. From the results of this study, it can be concluded that the present design of LNG cargo tank satisfies the requirement by KOGAS.

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Ice Collision Analyses for Membrane Tank Type LNG Carrier

  • Suh, Yong-Suk;Ito, Hisashi;Chun, Sang-Eon;Han, Sang-Min;Choi, Jae-Yeon;Urm, Hang-Sub
    • Journal of Ship and Ocean Technology
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    • v.12 no.1
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    • pp.35-44
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    • 2008
  • As arctic energy resource is attracting public attention, arctic shipping market will also be growing in large as expected to increase in LNG trade from Arctic area to the western countries by shipping. During the voyages through such routes, collision with icebergs may be possible. In the present report, ice collision analyses are carried out from a practical point of view to verify the safety of hull structural strength of LNG carriers equipped with GTT $MKIII^{TM}$ membrane type cargo containment system. From the results of collision analyses and the operation-friendly design concept of no-repairing of cargo containment system, a safe operating envelope against ice collision is proposed for LNG carriers of membrane type cargo containment system. Based on the currently proposed safety criteria, it is concluded that LNG carriers with membrane tank type can operate safely with regard to the integrity of CCS in regions where collision between LNG carrier and iceberg is expected.

Weldability of STS316L for LNG Carrier by Fiber Laser (파이버 레이저를 이용한 LNG선용 STS316L의 용접특성)

  • Kim, Jong-Do;Lee, Jae-Beom;Lee, Chang-Je;Song, Moo-Keun;Nam, Gi-Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.8
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    • pp.1061-1068
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    • 2012
  • These days, world wide interest about global warming and environmental pollution and exhausting fossil fuel which have been main energy source in all around the world. So many country have tried to find out the solution by investing new & renewable and clean energy. Therefore LNG have been widely used as a substitution of fossil fuel and clean energy that emits less pollutant like SOx, NOx. Therefore LNG consumption has been quickly raised and LNG carriers have been getting larger for decades. In this study, high power fiber laser was used for welding of stainless steel for LNG carrier to increase its productivity. Used material was STS316L which has low carbon less than 0.03% and its thickness was 8 mm. We carried out bead, lap and butt welding by using the fiber laser which has maximum power up to 5kW. As a result, we could find out that lap and butt joint was possible at welding speed of 2.0m/min and 3.0m/min respectively.

Study on the characteristics of perlite insulation for the storage tank in LNG carrier (LNG선박 화물창의 펄라이트 단열재 적용성에 관한 설계 특성 연구)

  • Yun, Sangkook
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.8
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    • pp.843-848
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    • 2013
  • As the LNG demands are growing, the constructions of LNG FPSO (Floating Production Storage and Off-loading) and LNG carriers have been constantly increased, and the various design of storage tank has been tried. This paper propose that the material of inner storage tanks is made of 5~9% Ni steel plate and perlite powder insulation instead of urethane foam block. It needs essentially to obtain the proper design specifications that are the pressure of perlite, the characteristics of resilient blanket as the pressure absorber, optimum thickness of blanket and design pressure of tank wall, etc. to enable the perlite insulation system to LNG carrier, The results show that the design thickness of blanket should be between 1/4 to 1/3 of insulation width and the optimum rate becomes 30%, and the design pressure be applied below 1,500 Pa with blanket thickness.

Optimal Design of Mud Flushing System in Ballast tank of LNG Carrier (LNG선 Ballast Tank Mud Flushing System의 최적설계)

  • Park, Sang Hyeop;Song, Yoo Seok;Kim, Young Bok
    • Transactions of the KSME C: Technology and Education
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    • v.4 no.2
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    • pp.85-92
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    • 2016
  • During ballast of a LNG carrier, the mud at the sea floor can enter the tanks together with the ballast water if the LNG terminal is located at shallow water region. In order to remove the mud deposited on the tank floor during deballasting, the mud flushing system in the ballast tanks is applied. In this study, various analyses to conform the efficiency in the mud removal are performed. In order to design the mud flushing system, the particle size of the mud is measured by particle size analyzer. Flushing performance is evaluated by numerical analysis. From the results of numerical analysis including flow field and piping system network, the optimized flushing system is determined.