• 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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• 2006.06a
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• pp.47-50
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• 2006

현재의 화석연료-기반 사회에서는 지구 온난화와 고유가 추세가 야기하는 경제적 피해, 에너지 안보우려, 세계 평화 위협 등에 자주 노출되고 있는 실정이다. 세계 각국은 이러한 화석연료 에너지원을 대체하는 환경-청정하고 기술-신뢰할 수 있으며 경제-감당할 수 있는 에너지 공급원인 수소를 기반으로 하는 미래의 수소-기반 사회로의 진입에 노력하고 있다. 특히, 청정한 에너지 운반체인 수소의 생산 기술 상업화가 더욱 더 절실히 요구되고 있다. 이 예비 연구에서는 이산화탄소 포획/저장 기술과 결합된 다양한 수소 생산 기술의 정량적인 예비 비교 평가가 수행되었다. 예비적인 비교 평가 기준으로 1) 이산화탄소 배출량: 2) 에너지 이용률; 3) 토지 점유율: 4) 수소 생산비용 등이 고려되었다. 이러한 기준에 따라 수소 생산 기술 가운데 네 가지 예비 기술 대안인 1) 원자력: 2) LNG; 3) 석탄: 4) 태양광 등이 비교되었다. 대안 기술의 비교 평가 체제로 계층 망형 구조-기반 되먹임 모델이 개발되었다. 이러한 수소생산 기술의 우선순위 선정 결과는 개별 대안 기술의 상대적인 장단점 및 기술적인 갭을 정량적으로 인식하는 데에 활용될 수 있다. 그러므로 이 예비 연구는 수소 생산 기술 연구자나 수소 경제 기획자한테 뿐만 아니라 이산화탄소 포획/저장 기술 개발자한테 도움이 되리라 본다.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.363-371
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• 2022

In this study, the operation characteristics of the internal reforming type molten carbonate fuel cell (MCFC) were studied using computational fluid dynamics (CFD) analysis according to the steam to carbon ratio (S/C ratio), operating temperature, and gas utilization. From the simulation results, the distribution of gas composition due to the electrochemical reaction and the reforming reaction was predicted. The internal reforming type showed a lower temperature difference than the external reforming type MCFC. As the operating temperature decreased, less hydrogen was produced and the performance of the fuel cell also decreased. As the gas utilization rate decreased, more gas was injected into the same reaction area, and thus the performance of the fuel cell increased.

• 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.