• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.349-356
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• 2020

The heat release rate (HRR) and fire growth rate of fire for the solid combustibles consisting of multi-materials was measured through the ISO 9705 room corner test, and the computational analysis in a closed compartment was performed to simulate a fire using the heat release rate prediction model provided by a Fire Dynamics Simulator (FDS). The method of predicting the heat release rate provided by the FDS was divided into a simple model and a pyrolysis model. Each model was applied and computational analysis was performed under the same conditions. As the solid combustible consisting of multi-materials, a cinema chair composed mostly of PU foam, PP, and steel was selected. The simple model was over-predicted compared to the predicted heat release rate and fire growth rate using the pyrolysis model in a closed compartment.

• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.424-429
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• 1993

Numeric characters are printed at the end part of nuclear fuel rod containing nuclear pellets. Fuel rods are discriminated and managed systematically by these characters in the process of producing fuel assembly. The characters are also used to examine manufacturing process of fuel rods in the survey of burnup efficiency as well as in inspection of irradiated fuel rod. Therefore automatic character recognition is one of the most important technologies in automatic manufacture of fuel assembly. In this study, character recognition system is developed. In the developed system, mesh feature extracted from each character written in the fuel rod has been compared with reference feature value stored in database, and the character is thus identified. In the result of experiment, 95.83 percent recognition rate is achievable.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.816-819
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• 2007

국내에서 IGCC 플랜트의 복합발전시스템의 평가는 여러 분야별로 진행되어 왔다. 크게 살펴보면 다음과 같다. 첫 번째는 가스터빈 쪽의 기술이다. 즉, 기존 천연가스를 이용하는 가스터빈을 어떻게 하면 석탄가스를 사용하는 IGCC 플랜트에 적합하게 맞출 것인가 하는 문제이다. 두 번째는 효율을 어떻게 하면 높일 수 있는가의 문제로서 석탄의 종류, 가스화 방법을 효율적으로 선택, HRSG(heat recovery steam generator)를 효율적으로 설계, 그리고 정제공정에서의 에너지 소비를 줄이는 분야였다. 세 번째는 어떻게 하면 오염을 줄일까의 문제로서 질소나 스팀 분사를 연계하여 NOx를 감소시키고 정제 공정에 사용되는 촉매를 개발한다던지 공정을 발달시키는 분야였다. 이 외에도 여러 종류의 연구가 이 분야에서 있었으나 주로 설계 분야의 연구가 주되였다. 이것은 발전소의 건설을 위한 초기 단계로서 당연한 결과일 수 있다. 그러나, 지금 IGCC 플랜트가 건설되는 과정에 있으므로 우리나라 전력계통 연계와의 문제도 생각해보아야 한다고 생각한다. 따라서 이번 연구에서는 IGCC 플랜트 운영의 불확실성이 약간이라도 존재하기에 이 플랜트가 기저발전 보다는 첨두발전 쪽이나 태양열/광발전, 풍력발전 등 다른 신재생에너지 자원처럼 독립된 전력 시스템으로 운영될 것이라 생각하고 이렇게 운영될 때는 발전소의 부하률의 변화가 심할 수 있다는 가정하에 플랜트의 부하률에 따른 석탄의 합성가스, 연료가스 전환량 및 전환효율 및 발전량 및 발전효율을 전산모사를 통해 예측해보았다.

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.21-28
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• 2009

The purpose of this study is to gain a better understanding of the effects of thermal stratification and partial fuel stratification on reducing the pressure-rise rate and emission in HCCI combustion. The engine is fueled with Di-Methyl Ether(DME) which has unique 2-stage heat release. Computational work is conducted with multi-zones model and detailed chemical reaction scheme. Calculation result shows that wider thermal stratification and partial fuel stratification prolong combustion duration and reduce pressure rise rate. But too wide partial fuel stratification increases CO and NOx concentration in exhaust gas, and decreases combustion efficiency.

• Composites Research
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• v.28 no.4
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• pp.143-147
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• 2015

This paper proposes laser ultrasonic technique for the impact damage inspection of hydrogen fuel tank and proves that the impact damage can be visualized using an ultrasonic wave propagation imager with an easy detachable sensor head as an impact damage inspection tool for hydrogen fuel tanks. Also the performances of the proposed ultrasonic propagation imager support it can be implemented in real-world technology when the hydrogen car becomes popular.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.171-178
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• 2016

Extensive efforts from all over the world have been made to solve energy problems, such as high oil prices, global warning due to the depletion of oil. Among them, biofuel has been drawing attention as a clean energy, which can replace fossil fuels. However, conventional biofuels were often converted from eatable biomass such as sugar cane, corn and soy which should be replaced with uneatable biomass. In this study, a techno-economical evaluation of the gasification of biomass waste with mixed alcohol synthesis process was performed. Considering available domestic biomass wastes, a 2000 ton/day conversion plant were assumed to produce 533000 L/day ethanol. Also, financial data from previous studies were evaluated and used and economical sensitivities with various operation conditions were established. Economic analysis were conducted by the payback period and internal rate of return (IRR) and net present value (NPV). Sensitivity analyses of raw material costs, initial investment, the major process cost, ethanol price changes and operating costs were all performed.

• Resources Recycling
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• v.17 no.3
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• pp.35-41
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• 2008

The study of coking technology to upgrade oil sand bitumen which is considered as alternative fuel was performed by using thermogravity analyzer and delayed coking reactor(600ml). To analyzed and compared coking characteristics of oil sand bitumen, the reactivities of oil sand bitumen were measured in the TGA. At the temperature conditions of $400{\sim}550^{\circ}C$ and the temperature rising velocity of $50^{\circ}C/min$. the termination time of coking reaction and conversion efficiencies increased with an increase of bed temperature. However the increase rate decreased over $450^{\circ}C$. So the coking reaction with oil sand bitumen might be over $450^{\circ}C$. Also the termination time decreased with increasing the temperature rising velocity. But the content of coke increased with increasing temperature rising velocity. At the experiments in the delayed coker, the temperature condition at maximum oil yield was $475^{\circ}C$ and the fuel properties of oil from coking reaction was almost equal with conventional diesel. It was verified that the coking process might be useful process to upgrade the oil sand bitumem by using API and SIMDAS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.449-456
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• 2010

The HCCI engine is a prospective internal combustion engine with which high diesel-like efficiencies and very low NOx and particulate emissions can be achieved. However, several technical issues must be resolved before HCCI engines can be used for different applications. One of the issues concerning the HCCI engine is that the operating range of this engine is limited by the rapid pressure rise caused by the release of excessive heat. This heat release is because of the self-accelerated combustion reaction occurring in the engine and the resulting engine knock in the high-load region. The purpose of this study is to evaluate the role of thermal stratification and fuel stratification in reducing the pressure rise rate in an HCCI engine. The concentrations of NOx and CO in the exhaust gas are also evaluated to confirm combustion completeness and NOx emission. The computation is carried out with the help of a multizone code, by using the information on the detailed chemical kinetics and the effect of thermal and fuel stratification on the onset of ignition and rate of combustion. The engine is fueled with dimethyl ether (DME), which allows heat release to occur in two stages, as opposed to methane, which allows for heat release in a single stage.

• Journal of the Korean Institute of Gas
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• v.14 no.6
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• pp.7-14
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• 2010

This study investigated the effect on reducing the pressure rise rate(PRR) in HCCI Engine by the variation of mixing ratio in the pre-mixture of DME and n-Butane that has different auto-ignition characteristics. In addition to measure of gas pressure in the engine cylinder, chemiluminescence image using the optical accessible engine and numerical analysis with multi-zones model were used to assess the combustion at each local area in the combustion chamber. The maximum PRR changes depending on mixing condition of DME and n-Butane. When DME is stratified and n-Butane is distributed uniformly, maximum PRR becomes lowest which is about 0.25MPa/ms and it corresponds to 5deg. retarding of CA50.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.171-173
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• 2018

섬이나 고립된 지역들은 디젤 발전기를 이용하여 전력 공급을 해왔다. 발전소와 송배전설비 증설에 대한 경제적 문제와 사회적 갈등이 심하기 때문이다. 최근 이러한 비용, 사회 그리고 환경 문제로 인해 에너지 자립섬에 대한 관심이 증가하고 있다. 에너지 자립섬이란, 태양광, 풍력 등 신재생에너지와 배터리를 이용해 필요한 에너지를 스스로 생산하고 사용하는 섬을 말한다. 따라서 디젤 발전기 화석연료 사용량과 유지보수 비용을 줄일 수 있다. 본 논문에서는 상위제어기에 해당하는 EMS(Energy Management System)를 이용해 디젤 발전기, 태양광 PCS(Power Conversion System)와 에너지저장장치(Energy Storage System: ESS)의 유기적인 운영으로 높은 에너지 자립률을 달성한 사례를 소개하고자 한다.