• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.380-386
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• 2020

This paper represents an analysis of the economic impact of firing natural gas/diesel and natural gas/by-product oil mixtures in diesel engine power plants. The objects of analysis is a power plant with electricity generation capacity (300 kW). Using performance data of original diesel engines, the fuel consumption characteristics of the duel fuel engines were simulated. Then, economic assessment was carried out using the performance data and the net present value method. A special focus was given to the evaluation of fuel cost saving when firing natural gas/diesel and natural gas/by-product oil mixtures instead of the pure diesel firing case. Analyses were performed by assuming fuel price changes in the market as well as by using current prices. The analysis results showed that co-firing of natural gas/diesel and natural gas/by-product oil would provide considerable fuel cost saving, leading to meaningful economic benefits.

• 설비공학논문집
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• 제22권7호
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• pp.442-447
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• 2010

FPSO (Floating Production Strorage and Offloading) method for LNG industry is efficient and facile compared to onshore NG (Natural Gas) treatment facility. Five simple natural gas liquefaction cycles for FPSO are presented and simulated in this paper. SMR (Single Mixed Refrigerant) cycle, SNE (Single Nitrogen Expander) cycle, DNE (Double Nitrogen Expander) cycle, PNE (Precooled Nitrogen Expander) cycle, and PDNE (Precooled Double Nitrogen Expander) cycle are compared. Simple analysis results in this paper show that precooling process and adding an expander in the liquefaction cycle is an effective way to increase liquefaction efficiency.

• 한국세라믹학회지
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• 제42권11호
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• pp.758-762
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• 2005

Gas valve for domestic use is used for flow control of LPG (Liquefied Petroleum Gas) or LNG (Liquefied Natural Gas) of which pressure is about $200\;mmH_{2}O(\fallingdotseq0.0196\;[bar])$. Currently, two kinds of valves such as rotary type and button type are widely used in many applications. But, these valves have some problems that they are not controllable and reliable. Piezo actuation combined with modem microelectronics provides a reliable, quiet, low energy, infinitely adjustable gas valve. In this paper, gas valve using piezo actuator which are bimorph and a circle type was studied. Also, Prototype for gas valve was manufactured and characteristics of the prototype gas valve were analyzed.

• Korean Chemical Engineering Research
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• 제60권3호
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• pp.371-376
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• 2022

액화 천연 가스는 도시가스로 공급되기 위해 기화의 과정을 거치는데 이 때 약 800 kJ/kg의 냉열이 발생한다. 현재 이 에너지는 모두 바다로 버려지고 있어 에너지 재순환 관점에서 보면 아주 심각한 에너지 낭비를 초래하고 있다. 본 연구에서는 이 점에 착안하여 버려지는 액화 천연 가스의 냉열을 활용할 수 있는 해수담수공정을 제안하고 이 공정을 최적화하여 고유 전력 소비와 경제성에 대해 분석하였다. 그 결과 제안된 공정의 에너지 소모량은 -5.2 kWh/m³, 담수생산 단가는 0.148 USD/m³으로 계산되어 현재까지 개발된 어떤 공정보다도 우수함을 확인하였다.

• 한국해양공학회지
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• 제32권5호
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• pp.380-385
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• 2018

With the tightening of environmental regulations (i.e., IMO Tier III), natural gas (NG) has been spotlighted as an eco-friendly fuel with few air pollutants other than nitrogen oxides (NOx) and sulfur oxides (SOx). For reasons of economic efficiency, it is mainly stored and transported in a liquid state at $-163^{\circ}C$, which is a cryogenic temperature, using a liquefied gas storage tank. Accordingly, it is necessary to reduce the boil-off gas (BOG) occurrence due to the heat flow according to the temperature difference between the inside and outside of the storage tank. Therefore, in this study, a BOG measurement test on an independent-type storage tank made up of SUS304L was carried out. The test results showed the tendency for BOG occurrence according to the temperature under different filling ratios.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.376-381
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• 2012

Natural gas is converted in to LNG by chilling and liquefying the gas to the temperature of $-162^{\circ}C$, when liquefied, the volume of natural gas is reduced to 1/600th of its standard volume. This gives LNG the advantage in transportation. The pressure dorp of the cascade liquefaction cycle was investigated and simulated using HYSYS software. The simulation results showed that the pressure drop in the LNG heat exchanger is set to 50 kPa considering the increase in the compressor work of cryogenic cascade liquefaction cycle.

• 동력기계공학회지
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• 제9권2호
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• pp.81-87
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• 2005

This study is numerical analysis on the increasing temperature characteristics of vaporizer fin for liquefied natural gas with super low temperature. Existing LNG vaporizers use the direct contact heat transfer mode where the extreme super low temperature LNG of $-162^{\circ}C$ flows inside of the tubes and about $20^{\circ}C$air flows on outside of the fin. Recently, the vaporizers with great enhanced performance compared to conventional type have been developed to fulfill these requirements. The vaporizing characteristic of LNG vaporizer with air as heat source has a fixed iced. These characteristic cause a low efficiency in vaporizer, total plant cost and installing space can be increased. The vaporizing characteristics of LNG via heat exchanger with air are analytically studied for an air heating type vaporizer. This study is intended to supply the design data for the domestic fabrication of the thickness and angle vaporizer fin. Governing conservation equations for mass, momentum and energy are solved by STAR-CD based on an finite volume method and SIMPLE algorithm. Calculation parameter is fin thickness, setup angle and LNG temperature. If the vaporization performance of the early stage and late stage of operating is considered, the case of ${\phi}=90^{\circ}$ was very suitable. In this paper was estimated that the heat transfer was most promoted in case of THF=2mm.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.940-945
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• 2005

In recent years, the LNGC fleet is expanded unprecedentedly. Ship's owners and shipbuilders are focusing on technology and reliability of new propulsion system from economical, environmental and safety angles. This paper give describes the new trend of propulsion system and boil off gas handling system from LNG carriers.

• 한국가스학회지
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• 제14권1호
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• pp.42-46
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• 2010

LNG (Liquefied Natural Gas)기지의 LNG 저장탱크에서 BOG (Boil Off Gas)가 약 0.5 vol%/day로 자연적으로 생성된다. 이를 회수하기 위해서 기존에는 LNG와 BOG를 1:12의 질량비로 직접 접촉시켜 액화시켰다. 이 공정은 단순하지만 하절기에는 LNG 사용량 저하로 인해 공정운영의 어려움이 있다. 이러한 단점을 보완하기 위해 대안된 LNG 냉열을 사용하는 간접접촉방식을 HYSYS를 이용하여 분석해보고 직접접촉방식과 BOG 재액화 효율비교를 통해 분석하여 유리한 공정을 도출하였다.

• 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.