• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.878-883
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• 2011

Effect of flow uniformity on the reaction characteristics of a catalytic combustor for high temperature fuel cell system has been experimentally investigated in the present study. One of the most important factor in designing catalytic combustion is to avoid hot spot in catalysts. In this regard, it is very important to secure flow uniformity of combustor inlet. A couple of perforated plates were applied at the front of catalyst region as flow uniformity device with minimal pressure drop. Results show that the velocity and temperature profile became more uniform when applying the flow uniformity device. CO and $CH_4$ emissions at the combustor exit were decreased and the average exit temperature was slightly increased with the flow uniformity device.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2000년도 춘계 학술발표회 논문집
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• pp.209-214
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• 2000

The catalytic heat exchanger, which integrates two functions of heat generation and heat exchange into one equipment, was designed and its characteristics were investigated by experiments. The surface of the fin tube was deposited with Pd catalyst. The conversion of the mixture in the catalytic heat exchanger was more significantly affected by the inlet velocity of the mixture than by the inlet temperature and equivalence ratio of the mixture. It was found that the catalytic surface area of the fin tubes should be sufficiently increased to make the combustion intensity of the catalytic heat exchanger as high as possible. Results showed that the fin tubes, placed in the triangularly staggered form, should be adjusted so that the mixture flows uniformly over all the catalytic fin surfaces.

• 한국수소및신에너지학회논문집
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• 제31권1호
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• pp.82-88
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• 2020

Recently, a fuel reforming plant for supplying high purity hydrogen has been studied to increase the operation time of underwater weapon systems. Since steam reforming is an endothermic reaction, it is necessary to continuously supply heat to the reactor. A fuel reforming plant needs a methanol-O₂ catalytic burner to obtain heat and supply heat to the reformer. In this study, two types of designs of a catalytic burner are presented and the results are analyzed through the experiments. The design of the catalytic burner is divided into that the O₂ supply direction is perpendicular to the methanol flow direction (Design 1) and the same as the methanol flow direction (Design 2). In case of Design 1, backfire and flame combustion occurred in the mixing space in front of the catalyst, and in the absence of the mixing space, combustion reaction occurred only in a part of the catalyst. For above reasons, Design 1 could not increase the exhaust gas temperature to 750℃. In Design 2, no flashback and flame combustion were observed, the exhaust gas could be maintained up to 750℃. However, the O₂ distributor was exposed to high temperatures, resulting in thermal damage.

• 대한기계학회논문집B
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• 제36권4호
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• pp.405-412
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• 2012

MCFC 발전시스템에서 연소기는 연료극의 배가스 중에 포함된 미반응 가스를 연료로 사용하여 공기극에 $H_2O$와 $CO_2$ 농도가 높은 고온의 혼합가스를 공급하는 역할을 한다. 하지만 이러한 배가스는 가연한계 이하로 내려가게 되어 통상적인 연소방식에 의한 완전연소가 어렵기 때문에 이를 해결하기 위하여 촉매연소기를 사용한다. 완전연소 및 이에 다른 공해물질의 저감 특성에 따라 최근 촉매연소는 환경친화적인 연소방식으로 주목받고 있다. 따라서 본 연구에서는 MCFC 발전시스템의 BOP 시스템에 적용되는 촉매연소기에 대한 실험연구를 수행하였다. 본문에서는 실험장치를 설명한 후 촉매연소 시스템의 설계변수, 즉, $H_2$ 연료 첨가에 따른 연료조성, 유입가스의 온도, 과잉 공기비, 촉매의 종류, 그리고 시동 스케줄에 따른 촉매연소 특성을 고찰하였다.

• 한국환경과학회지
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• 제11권6호
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• pp.577-582
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• 2002

Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increased with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850$\^{C}$ of optimal condition.

• 센서학회지
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• 제17권3호
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• pp.178-182
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• 2008

Planar type micro catalytic combustible gas sensor was developed by using nano crystalline $SnO_2$ Pt thin film as micro heater was deposited by thermal evaporation method on the alumina substrate. The thickness of the Pt heater was around 160 nm. The sensor showed high reliability with prominent selectivity against various gases(Co, $C_3H_8,\;CH_4$) at low operating temperature($156^{\circ}C$). The sensor with nano crystalline $SnO_2$ showed higher sensitivity than that without nano crystalline $SnO_2$. This can be explained by more active adsorption and oxidation of hydrogen by nano crystalline $SnO_2$ particles. The present planar-type catalytic combustible hydrogen sensor with nano crystalline $SnO_2$ is a good candidate for detection of hydrogen leaks.

• 한국수소및신에너지학회논문집
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• 제30권3호
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• pp.209-219
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• 2019

Methanol is a liquid fuel which could also be produced from renewable energy sources and has appreciably high energy density. In this work, we investigated the application of $Ce_{0.9}Gd_{0.1}O_{2-x}$ supported Cu and Ni catalysts for hydrogen production via methanol steam reforming. Catalysts were synthesized by solution combustion synthesis. The prepared catalysts with various active materials and Cu loading amounts were tested in a reactor at $200-300^{\circ}C$, 0-5 barg range and steam to methanol molar ratio was 1.5. The catalytic properties of Cu and Ni were compared, and the catalytic performance was shown to depend on the amounts of metal loading and operating conditions such as reaction temperature and pressure.

• 센서학회지
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• 제18권3호
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• pp.202-206
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• 2009

Flat type catalytic combustible hydrogen sensors were fabricated using platinum micro-heaters and sensing material pastes. The platinum micro-heater was formed on an alumina substrate by sputtering method. The paste for the sensing materials was prepared using ${\gamma}-Al_2O_3$ 30 wt%, $SnO_2$ 35 wt%, and Pd/Pt 30 wt% and coated on the platinum micro-heater. The sensing performances were tested for the prepared sensors with different substrate sizes. The micro catalytic combustible hydrogen sensors showed quick response time, high reliability, and good selectivity against various gases(CO, $C_3H_8,\;CH_4$) at low operating temperature of $156^{\circ}\C$.

• 에너지공학
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• 제6권1호
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• pp.34-40
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• 1997

자동차 촉매인 Pd/cordierite 촉매상에서 메탄의 연소시험을 통하여 천연가스 이용기술 활용가능성에 대해서 고찰하였다. 중고온 연소에서 알맞은 비표면적 18.7$m^2$/g 을 갖으며 안정한 구조를 확인하였다. 메탄 연소 반응시 활성화에너지는 19.2 kcal/mol로써 비교적 우수한 활성을 보여주었으며, 메탄 연소 반응의 승온과 온도를 내리면서 촉매의 비활성 특성을 보여주는 활성 히스테리시스 현상을 관찰하였다. Pd/cordierite 촉매상에서 반응온도 $700^{\circ}C$이하에서 공간속도와 공연비를 변화시키면서 메탄 연소특성을 수행하였다.

• 청정기술
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• 제20권4호
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• pp.359-366
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• 2014

연소전 $CO_2$ 흡수제인 PKM1-SU와 원유의 접촉분해 촉매인 FCC (fluid catalytic cracking)입자의 고온, 고압 조건 마모 실험을 수행하였다. 지름 15.1 cm, 높이 120 cm에 스파저 튜브(sparger tube, 1 mm 오리피스)를 장착한 원통형 기포유동층반응기를 이용하여, 다양한 온도조건($0{\sim}400^{\circ}C$), 압력조건(0~20 bar)에서 입자마모 실험을 수행하였다. BET, 광학현미경, 입도분석기 등을 이용하여 실험 전, 후 입자를 분석 하였다. 또한 기존의 마모도 측정 방법인 ASTM D5757-95방법을 이용하여 층물질의 높이(4.4~10.2 cm) 및 수분 주입이 입자 마모에 미치는 영향에 대하여 확인하였다.