• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.103-106
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• 2006

The Plate reformer consisting of combustion chamber and reforming chamber for 25 kW MCFC stack has been operated and computational fluid dynamics was applied to estimate reactions and thermal fluid behavior in the reformer. The methane air 2-stage reaction was assumed in the combustion chamber, and three step steam reforming reactions were included in the calculation. Flow uniformity, reaction rate and species distribution, and temperature distribution were analyzed. In particular, temperature distribution was compared with the measurements to show good agreement in the combustion chamber, however, inappropriate agreement in the reformer chamber

• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.403-408
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• 2006

The plate reformer consisting of combustion chamber and reforming chamber for 25 kW MCFC stack has been operated and computational fluid dynamics was applied to estimate reactions and thermal fluid behavior in the reformer. The methane air 2-stage reaction was assumed in the combustion chamber, and three step steam reforming reactions were included in the calculation. Flow uniformity, reaction rate and species distribution, and temperature distribution were analyzed. In particular, temperature distribution was compared with the measurements to show good agreement in the combustion chamber, however, inappropriate agreement in the reformer chamber.

• 한국수소및신에너지학회논문집
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• 제22권3호
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• pp.357-362
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• 2011

Complete mixture preparation of reactants prior to catalytic reforming is an enormously important step for successful operation of a fuel reformer. Incomplete mixing between fuel and reforming agents such as air and steam can cause temperature overshoot and deposit formation which can lead the failure of operation. For that purpose it is required to apply computational models describing coupled kinetics and transport phenomena in the mixing region, which are computationally expensive. Therefore, it is advantageous to analyze the gas-phase reaction kinetics prior to application of the coupled model. This study suggests one of the important design constraints, the required residence time in the mixing chamber to avoid substantial gas-phase reactions which can lead serious deposit formation on the downstream catalyst. The reactivity of various gaseous and liquid fuels were compared, then liquid fuels are far more reactive than gaseous fuels. n-Octane was used as a surrogate among the various hydrocarbons, which is one of the traditional liquid fuel surrogates. The conversion was slighted effected by reactants composition described by O/C and S/C. Finally, threshold residence times in the mixing region of a hydrocarbon reformer were studied and the mixing chamber is required to be designed to make complete mixture of reactants by tens of milliseconds at the temperature lower than $400^{\circ}C$.

• 한국융합학회논문지
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• 제11권10호
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• pp.231-236
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• 2020

물 개질반응 고속선회 소각로 시험 설비를 제작하였다. 개질 반응실과 연소실은 직접 연결이 되게 하였다. 소각로와 집진 장치는 일체형으로 만들어 2중 격벽식 공기 냉각 구조로 만들었다. 송풍기를 집진장치 내부에 내장하여 공간적으로 효율성을 향상시켰다. 집진부의 옆에 부착된 다수의 집진통을 이용하여 분진을 수거하여 백필터가 별도로 필요없는 축류 유동형 다단식 집진장치를 적용하였다. 배출되는 가스 중 다이옥신을 측정한 결과 기준치 이하의 결과를 얻었다. 배출가스와 중금속을 측정한 결과 환경기준치 이하의 결과를 얻었다.

• 한국수소및신에너지학회논문집
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• 제13권2호
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• pp.159-167
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• 2002

The operation results of the 2kW class plate type reformer, which has several advantages compared with the tubular burner type reformer, are analyzed. This plate type reformer is composed of six combustion chambers and five reforming chambers by turns. The methane conversion rate at 1.6 absolute pressure is about 84%, which is reasonably similar to theoretical value, 85.3%. Though the abrupt interruption was made just by the carbon deposition during heating the fuel line to combustion chambers around 200 hours operation, the overall steady state operation is more than 450 hours. These operation results show the verification of long run performance and the possibility of direct connection between plate reformer and fuel cell stack.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.364-374
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• 2010

Design of a reformer consisting of combustion chamber and reforming chamber was investigated for a 1 kW and a 5 kW polymer electrolyte membrane fuel cell (PEMFC), respectively, using the computational fluid dynamics (CFD). First, the 1kW reformer was considered to obtain the reliability of the numerical study. It was modeled, calculated and compared with experimental data. Second, the 5kW reformer was considered for a geometric study. Three tip sizes (35, 40, and 45 mm) and five aspect ratios was selected. It was found that the optimum was at tip sizes of 40 and 45 mm, at aspect ratios of -10% and -20% of the standard length.

• 청정기술
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• 제26권4호
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• pp.329-335
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• 2020

재생에너지로부터 수전해를 통하여 생산된 수소와 포집된 CO2를 활용하여 메탄올을 합성하는 power-to-methanol 기술이 재생에너지를 대용량으로 저장하는 방안으로 제시되고 있다. 본 연구에서는 메탄올을 수소 및 전력 생산에 활용함에 있어 더욱 효율적인 방법으로 연료전지 내부에서 메탄올 수증기개질 반응이 일어나는 내부개질형 용융탄산염 연료전지에 대해 성능 분석을 실시하였다. 용융탄산염 연료전지의 연료극으로 사용되는 다공성 Ni-10 wt%Cr을 촉매로 메탄올 수증기개질 반응을 수행한 결과 연료전지 운전 조건에서 연료극은 메탄올 수증기개질 반응에 충분한 활성을 나타내었다. 메탄올 수용액을 직접 용융탄산염 연료전지의 연료극으로 공급한 결과 연료전지의 성능은 외부 개질기를 통하여 생산된 개질가스를 공급하는 경우에 비해 다소 성능이 낮게 나타났으며, 메탄올 공급유량이 비교적 낮은 경우 고 전류밀도에서 불안정한 성능을 나타내었다. 연료극으로부터 생성된 가스를 재순환시킴으로써 연료전지의 성능을 향상시킬 수 있었으며, 메탄올 전환율도 90% 이상 얻을 수 있었다. 물질수지를 통하여 연료극에서 일어나는 반응을 분석한 결과 전류밀도 및 가스 재순환 유량이 증가함에 따라 메탄올 수증기개질 반응속도가 증가함을 확인하였다. 이상의 결과로부터 별도의 촉매층을 설치할 필요 없이 연료극 만으로도 용융탄산염 연료전지 내에서 메탄올 수증기개질 반응이 가능하며, 메탄올 내부개질형 용융탄산염 연료전지를 통하여 전력과 합성가스를 동시에 생산할 수 있음을 확인하였다.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.14-21
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• 2008

Synthetic gas is defined as reformed gas from hydrocarbon-based fuel and the major chemical species of the synthetic gas are $H_2$, CO and $N_2$. Among them, hydrogen from synthetic gas is very useful species in chemical process such as combustion. It is a main reason that many studies have been performed to develop an effective reforming device. Furthermore, other technologies have been studied for synthetic gas application, such as the ESGI(Exhaust Synthetic Gas Injection) technology. ESGI injects and burns synthetic gas in the exhaust pipe so that heat from hydrogen combustion helps fast warmup of the close-coupled catalyst and reduction of harmful emissions. However, it is very hard to understand combustion characteristic of hydrogen under low oxygen environment and complicated variation in chemical species in exhaust gas. This study focuses on the characteristics of hydrogen combustion under ESGI operating conditions using a CVC(Constant Volume Chamber). Measurements of pressure variation and flame speed have been performed for various oxygen and hydrogen concentrations. Results have been analyzed to understand ignition and combustion characteristics of hydrogen under lower oxygen conditions. The CVC experiments showed that under lower oxygen concentration, amount of active chemicals in the combustion chamber was a crucial factor to influence hydrogen combustion as well as hydrogen/oxygen ratio. It is also found that increase in volume fraction of oxygen is effective for the fast and stable burning of hydrogen by virtue of increase in flame speed.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.286-294
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• 2010

According to the propagation of fuel cell system, the importance of that system efficiency is being magnified. Thus, the efficiency improvement of reformer which is the important part of fuel cell system will be required. In structural aspect, the reformer is classified into cylindrical and plate type. Plate type reformer features better maintenance and space efficiency compared with cylindrical type. In this study, we changed the shape of combustion chamber to improve the reforming efficiency. And then we performed the CFD simulation to predict the spacial distribution of temperature. Analysis cased contains with baffles, fins, baffles and fins, and without those. In case of only with-baffle, temperature distributions were uneven because the high temperature stream was concentrated near the baffle end. In case of with-fin, the temperature distributions were relatively even than other cases.

• 한국가스학회지
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• 제5권4호
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• pp.27-32
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• 2001

온실효과의 주요 원인 물질인 이산화탄소를 고온$\cdot$고압에서 제거하기 위한 CaO 흡착제를 제조하였다. 흡착제는 석회석을 고압성형과 소성을 이용하여 제조하여 그 물성을 조사하고 회분식 흡착용기에서 흡착실험을 수행하였다. 세공면적은 성형압력으로 결정되며 세공분포는 이분산 형태를 갖는다. CaO의 $CO_2$ 흡착은 화학흡착이며 최대전환율은 $700^{\circ}C$에서 $80\%$에 근접한다.