• Structural Engineering and Mechanics
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• v.81 no.6
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• pp.781-790
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• 2022

The present paper describes a general procedure of the structural safety assessment for the independent type C tank of LNG bunkering ship. This strength assessment procedure consists of two main scheme, global Finite Element Analysis (FEA) model primarily for hull structure assessment and detailed LNG Tank structures FEA model including the cylindrical tank itself and saddle-support structures. Two kinds of mechanism are used, fixed and slides constraints in fore and rear of the saddle-support structures that result in a variation of the reaction forces. Finite Element (FE) analyses have been performed and verified by the strength acceptance criteria to evaluate the safety adequacy of yielding and buckling of the hull and supporting structures. The detail of FE model for an LNG type C tank and its saddle supports was made, which includes the structural members such as cylindrical tank shell, ring stiffeners, swash bulkhead, and saddle supports. Subsequently, the FE buckling analysis of the Type C tank has been performed under external pressure following International Gas Containment (IGC) code requirements. Meanwhile, the assessment is also performed for yielding and buckling strength evaluation of the cylindrical LNG tank according to the PD 5500 unfired fusion welded pressure vessels code. Finally, a complete procedure for assessing the structural strength of 500 CBM LNG cargo tank, saddle support and hull structures have been provided.

• Korea Trade Review
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• v.45 no.6
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• pp.99-112
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• 2020

It is no exaggeration to say that today's world economy is dependent on international trade, which is the result of inter-state transactions. As the vast majority of international goods transport is transported by international shipping, interest in the seaborne transport field is natural in international and trade studies. In particular, in the case of international shipping, as it is the basis of typical international transportation, changes in international shipping due to the innovation of technology may have an effect on international trade norms. In this study, as a result of evaluating port preference in a hypothetical scenario by using the Design of Experiments method, bunkering as well as port service, which is traditionally important, was identified as a major competitive factor of future ports. It has been revealed that, above all, the port to respond to the future is the continued importance of port services and the supply of ship fuel. Therefore, port authorities are providing implications that LNG bunkering infrastructure suitable for international environmental regulations is important.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.876-880
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• 2015

In 2016, the IMO's new rules for an 80% reduction in NOx emissions in newly built ships will necessitate the use of LNG as a clean fuel. So far, the developed European countries have led the development of LNG bunkering ships and related facilities. An LNG bunkering system stores LNG in a horizontal or vertical IMO "C"-Type tank insulated with perlite powder, and a vacuum in the annular space between the double walls, like the cryogenic liquid nitrogen tank. Current storage tanks have high heat leakage, evaporating over 2.0% daily, and are difficult to build with the required vacuum. A more efficiently insulated storage tank could reduce the evaporation rate. This research carried out thermal analysis on a new effective insulation method that separates high vacuum in the annular space between two tanks with a solid insulation material, such as urethane foam, lining the outer vessel. This highly efficient insulation system obtained an evaporation rate of 0.03% per day under a $10^{-3}torr$ vacuum, and an evaporation rate of 0.11% at $10^{-45}torr$. Even if the space loses its vacuum, the new insulation system showed a lower evaporation rate of 4.12% than the present perlite system of 4.9%. This newly developed tank can increase the efficiency of LNG storage tank and may help keep LNG bunkering systems safe.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.47-49
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• 2016

국제해사기구가 선박배출가스규제지역 내 질산화물 규제를 적용하고 2020년부터는 항해 중인 모든 선박에 황산화물 규제를 적용하기로 하는 등 선박해양오염 규제가 강화되어, 친환경 연료로 운항하는 LNG Fuel Ship에 대한 수요가 높아지고 있다. 이로 인해 LNG 연료공급 시장규모의 성장이 전망되며 관련시설로 해상 부유상태의 FLBT(Floating LNG Bunkering Terminal)의 기술개발과 연구가 진행 중에 있다. 본 연구목적은 FLBT 시설의 설치에 적합한 후보지를 선정하는 것이다. 영해 내에 위치하고 설계수심과 수요항만과 접근성이 우수한 후보지의 제시를 위해 LNG Fuel Ship의 입출항 예상항만과 해상시설에 대한 국내외 사례조사 및 사전연구에서 제시된 후보수역에 대한 해상교통조사를 수행하고 심층분석 하였다. 조사 및 분석결과를 바탕으로 수요지 접근성과 항행안전을 고려한 FLBT 최종 후보지를 제시하고자 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.856-867
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• 2020

This paper aims to provide the most useful method of determining an optimum LCB position and design direction of fore- and aft-body hull shape for a SLBV. It is known that the SLBV has a lower length-to-beam ratio, larger Cb and simpler stern shape designed for the installation of azimuth thrusters comparing to those of conventional LNG carriers. Due to these specific particulars of SLBV, the optimum LCB position was very different to that of conventional LNG carrier. And various approaches were applied to determine the optimum fore- and aft-body hull shape. The design direction for the optimum hull-form was evaluated as the minimization of the total resistance which includes the wave-making resistance and form-drag with numerical simulation.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.37-37
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• 2017

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.1-6
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• 2018

An LNG bunkering system stores LNG in a horizontal IMO's C-Type tank insulated with perlite powder, and $10^{-2}$ Torr vacuum in the annular space between the double walls. Current storage tanks have high heat leakage, evaporating over 2.0% daily. A more efficiently insulated storage tank reducing the evaporation rate is required to develope. This research carried out thermal analysis on a new effective insulation method, i.e. double shield insulation system, that separates high super vacuum in the annular space between two tanks with a perlite vacuum in the back side of outer tank. This highly efficient insulation system obtained an evaporation rate of 0.16% per day under a $10^{-4}$ Torr vacuum. Even if the space loses its vacuum, the new insulation system showed a lower evaporation rate of 5.23% than the present perlite system of 4.9%.

• Journal of Ocean Engineering and Technology
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• v.34 no.2
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• pp.77-88
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• 2020

In this study, heading characteristics and heading control performances were evaluated to achieve the wave shield effect. The wave shield effect originating from heading control reduces the relative motions of moored vessels in a floating liquefied natural gas bunkering terminal (FLBT). Therefore, loading and off-loading performances are improved through reduced relative motion. For the objective of this study and efficiency of the analysis, a simplified model was used that assuming no relative motion of the moored vessels in the FLBT. The simplified model involved modeling the environmental loads and inertia of several floating bodies, including FLBT, into the environmental loads and inertia of a single vessel. The simplified model was validated through comparisons with model tests. With the simplified model, heading characteristics and heading control simulations were performed using low-frequency planar motion equations. The heading characteristics and heading control performances of FLBT were analyzed through the results of simulations under the expected environmental conditions. The capacity of the tunnel thrust for the heading control performance was confirmed to be adequate for improvement of the loading and off-loading performances using the wave shielding effects under the operation conditions.

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.239-273
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• 2007

Bunker-C is sold at the different price in the market for international bunkering and for export, though the quality of bunker-c is not much different in two markets. The price difference in two markets tends to increase since 2002 in Korea. This study shows that there is a possibility for a structural change in the price difference in two markets in Korea around June, 2002. In the search for possible explanations for this structural change, empirical analyses found that the price difference in Singapore, which had not have any explanatory power before June, 2002, has explained the price difference in Korea after July, 2002. Other explanatory variable for the price difference was the growth rate of crude oil price in the previous period. The empirical results suggest that the price difference in bunkering market and export market might be explained by the price discrimination which is adopted as a competitive strategy by oil companies in competing with Singapore.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.158-161
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• 2018

In this paper, the towing force is calculated for the LNG bunker barge. LNG bunkering barge is being developed as an infrastructure for the bunkering of LNG(Liquefied Natural Gas), an eco-friendly energy source. In the case of the LNG bunker barge, a self-propulsion is considered through retrofit from an operating point. Therefore, the LNG bunker barge is similar to the shape of the ship as compared to a towed barge, so a rule of the towed barge overestimates the towing force. In order to improve accuracy, the calm water resistance is calculated according to the ITTC 1978 method considering the wave resistance by the Rankine source method. The added resistance in waves is calculated using the modified radiated energy method considering the shortwave correction method of NMRI. The performance of the towing resistances through the calm water resistance and the added resistance in waves was compared with rules of the towed barge.