• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.94-96
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• 2013

Since LNG has explosive properties and difficulty to handle, it was avoided using LNG as fuel. However, recently LNG has been considered as alternative fuel of HFO. Several LNG fuel supply system has developed. Furthermore, STX ONS is developing LNG fuel bunkering system and bunkering shuttle. Bunkering shuttle carries out refueling LNG fuel while LNG fuel ship is on cargo work. In case of emergency, bunkering shuttle breakaway from the ship but a little amount of LNG falls down on deck. It can disperse to cargo work area also can explode. In this case LNG dispersed on deck was not considerable.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.5
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• pp.447-452
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• 2016

The use of gas as fuel, particularly liquefied natural gas (LNG), has increased in recent years owing to its lower sulfur and particulate emissions compared to fuel oil or marine diesel oil. LNG is a low temperature, volatile fuel with very low flash point. The major challenges of using LNG are related to fuel bunkering, storing, and handling during ship operation. The main components of an LNG fuel system are the bunkering equipment, fuel tanks, vaporizers/heaters, pressure build-up units (PBUs), and gas controlling units. Low-pressure dual-fuel (DF) engines are predominant in small LNG-powered vessels and have been operating in many small- and medium-sized ferries or LNG-fueled generators.(Tamura, K., 2010; Esoy, V., 2011[1][2]) Small ships sailing at coast or offshore rarely have continuous operation at constant engine load in contrast to large ships sailing in the ocean. This is because ship operators need to change the engine load frequently due to various obstacles and narrow channels. Therefore, controlling the overall system performance of a gas supply system during transient operations and decision of bunkering time under a very poor infrastructure condition is crucial. In this study, we analyzed the fuel consumption, the system stability, and the dynamic characteristics in supplying fuel gas for operating conditions with frequent engine load changes using a commercial analysis program. For the model ship, we selected the 'Econuri', Asia's first LNG-powered vessel, which is now in operation at Incheon Port of South Korea.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.841-846
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• 2008

Recently the LNG(liquified natural gas) public buses have been introduced to prevent the air pollution in metropolitan areas. As the LNG temperature in fuel tank is as low as $-162^{\circ}C$. the thermal and structural effects of tank components need to be studied for safe introduction in the market. Especially the support system of LNG fuel tank in vehicle, which has connected with inside and outside of tanks, should put attention to reduce the structural stress due to cryogenic temperature and to restrict the heat flux from ambient. There are two supporting systems in the tank, that one is connected between inside and outside tanks by welding, and the other is the inserted support system which is a cylindrical SUS bar inserted in a hole of the supporting plate. In this study the temperature distribution and thermal stress of the inserted support system were evaluated by using the utility program as ANSYS. The results showed that the rate of heat transfer to inner tank through this support system was quite small due to limited contact of support bar with plate. but the thermal stress of support plate was obtained beyond the limited tensile value of SUS304. The cautious design for the support plate part, therefore, should be given to make the safe support system of LNG vehicle fuel tank.

• Special Issue of the Society of Naval Architects of Korea
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• 2015.09a
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• pp.9-13
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• 2015

While environmental concern is urging shipbuilding industry to reduce pollutant emission, it is necessary to design environmental friendly vessels. LNG as fuel for ship propulsion is proven to be effective way to reduce pollutant emission. In this study, we find optimum position of LNG fuel supply system on AHTS by considering vessel characteristic. Three different positions of fuel supply system are studied in this paper. Factors such as stability, strength and safety are examined in each position of fuel supply system.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.54-58
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• 2017

The vessels which are operated in ECA (Emission Control Area) after $1^{st}$ January 2016 shall be complied with revised NOx emission requirement (Tier III). Effective solutions for NOx emission requirement are SCR (Selective Catalytic Reduction), EGR (Exhaust Gas Recirculation) and Installation of LNG Dual Fuel Engine. This study is considered the design modification as per application of LNG Ready notation. In case of LNG Ready - S notation, the vessel shall be retrofitted the Main engine with Dual fuel engine and LNG Fuel system after delivery. On this paper, the entire process for design modification was explained to meet the requirement for LNG Ready notation.

• Journal of the Korean Society of Safety
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• v.27 no.4
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• pp.76-82
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• 2012

A diesel-Liquefied natural gas(LNG) combustion engine truck fleet demonstration project had been carried out and commercial expansion project was launched. The key issues of these projects are the safety of LNG fuel station and the reduction of natural gas relief. When LNG is fueled to LNG vehicles the heat is input in the LNG system. The LNG in the fueling system was boiled and the vapor of LNG is vented through the safety devices. The temperature of the vapor of LNG is $-108^{\circ}C$ and density is heavier than air. It can be dispersed to downside of the fuel station. The safety evaluation is carried out using CFD program and risk assessment program for the vapor of LNG in the LNG vehicle fuel station. The hazards are identified and suggested the operation instruction to reduce the relief of LNG vapor.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.162-163
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• 2018

A risk assessment is performed at the initial design stage of LNG-fuelled ships subject to new fuel supply systems due to marine environmental and emissions regulations. Risk assessment involves a series of logical steps that enable systematic risk analysis and evaluation. LNG-fuelled ships mainly consist of a tank for storing LNG, a gas supply unit for supplying LNG to the engine, an engine using LNG as fuel, and a bunkering manifold for receiving LNG. The components of the LNG fuelled ship are determined according to the characteristics, size, rout, and operating distance. Therefore, the risk factors of each ships are different, and the risk analysis also changes. In this study we consider the systems of ships using LNG as a fuel and analyze the risk assessment of certain cases where the actual risk assessment has been carried out.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.90-93
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• 2013

RAM study has been used for various range of industry such as chemical, electronics, defense industry. Recently, in the offshore & shipbuilding industry, demand of owners to analysis risk has been increased. RAM study is a quantitative pointer to risk based design and provides effective method for improvements. This article shows the result of RAM study for LNG fuel supply system. The result provides information to improve design. This study shows how result of risk assessment affects the design of LNG fuel supply system.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.70-76
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• 2017

This paper presents the development of a Gas Valve Train (GVT) control system which is the core equipment of LNG fueled vessels. Due to the increasing worldwide demand for echo friendly green ship products, domestic companies urgently require to develop a core equipments for the LNG fueled vessels to secure worldwide markets in marine engineering. A LNG fueled engine generally equips the GVT, a fuel supply system that steadily supplies clean high-pressure LNG to the engine. The GVT requires a safety operational control system that can prevent any gas leakage accident, and a system that monitors operation status in real time. Therefore, we introduces a development for GVT control and monitoring system design and the design was systematically performed by means of functional analysis and differentiation of foreign advanced products.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.45-52
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• 2018

As guidelines for exhaust gases of ship are reinforced by the International Maritime Organization, the necessity for LNG fuelled ship is emerging. The relevant research is actively progressing to develop technologies and promote commercialization. When the residual quantity of LNG fuel tank is less than 70% by consuming fuel during operation, sloshing should be considered. We applied the Type C LNG fuel tank because medium sized LNG fuelled ships are difficult to equip with re-liquefaction system. Structural integrity and thermal performance are very important, especially in LNG fuel tanks that apply to LNG fuelled ship. Through this study, we proposed evaluation procedure of thermal performance for the Type C LNG tank, and verified the validity and effectiveness of BOR(Boil-Off Rate) test Procedure by comparing and analyzing changes in temperature, pressure, BOG(Boil-Off Gas).