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C_(1)-HVOCs 제거를 위한 Ru-Sn/γ-Al_(2)O_(3) 촉매 제조 및 반응성 평가
김영주,황운연,구기갑,김용렬,박종수,윤왕래 한국화학공학회 2004 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.42 No.1
HVOCs 제거에 사용되는 백금-팔라듐계보다 저렴한 촉매 개발을 목적으로 다양한 루테늄계 촉매를 제도하여 C_(1)-HVOCs 분해 특성 평가 실험을 수행하였다. 그 결과 Ru[2]-Sn[2]/γ-Al_(2)O_(3) 촉매가 가장 우수한 성능을 보였다. 구조 증진제인 주석은 흡착 산소의 양을 증가시키고, 다양한 산소 이온 종의 생성에 기여함을 알 수 있었다. HVOCs 분해 반응에 첨가되는 산소 원자는 주로 루테늄과 주석에 흡착되며, CH_(3) 등 HVOCs는 지지체인 γ-Al_(2)O_(3)의 브뢴스테드 및 루이스 산점에 흡착됨을 알 수 있었다. 흡착된 HVOCs의 염소와 브뢴스테드 산점의 수소 화학 결합에 의한 HCl의 생성 반응이 HVOCs 분해의 주 반응 기구임을 알 수 있었다. Various ruthenium(Ru) based catalysts, which were less expensive than Pt-Pd based catalysts, were prepared and their activity with C_(1)-HVOCs(Halogenated Volatile Organic Compounds) was evaluated. Ru[2]-Sn[2]/γ-Al_(2)O_(3) was found to have the most desirable effect on the destruction of HVOCs. Tin taken as a structural promoter was found to increase the amount of oxygen adsorption and to generate various oxygen ions. Oxygen atoms were found to be mainly adsorbed on the surface of ruthenium and tin and HVOCs such as CH_(3)Cl to adsorbed on Bronsted and Lewis acid sites of γ-Al_(3)O_(3) supports. It was found that the formation of HCl by the reaction of chlorine in HVOCs with hydrogen atom on Bronsted acid site was the main reaction mechanism in the destruction of HVOCs.
Recent developmental status and prospects of hydrogen refueling stations
( Wang Lai Yoon ),( Dong Joo Seo ) 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.1
Hydrogen refueling infrastructure to support the introduction of fuel cell and other hydrogen(and hydrogen mixture)-fueled vehicles is seen as one of the key factors for the transition to the hydrogen economy. Basically, hydrogen station can be configured by any combination of six modules : hydrogen generator, purifier, compression, storage, dispenser and power generator. And there can be several ways in hydrogen delivery for use at refueling stations. In the early demonstration phase, the use of distributed hydrogen refueling system(cryogenic liquid hydrogen, compressed hydrogen, reforming of hydrocarbonfeedstocks such as natural, gas, LPG and naphtha, electrolysis of water) may be a intermediate pathways to infrastructure development with future development of hydrogen pipeline delivery. The understanding of the implications of each system as well as comparisons between the choices of generation methods for use is essential in developing the refueling infrastructure. In this session, we present the recent developmental status and prospects of hydrogen refueling stations in advanced countries such as America, Japan, and Europe. Especially, national demonstration programs to promote early introduction of hydrogen fueled vehicles are reviewed.
5㎾급 고분자연료전지용 천연가스 개질기 시스템 운전 특성 연구
윤왕래,박종원,이영우,한명완,정진혁,박종수,정헌,이호태,김창수 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.3
가정용 고분자 연료전지 스택운전에 필요한 수소공급기술로서 천연가스 수증기 개질법에 기초한 5k급 열 및 시스템 통합형 연료개질기 시작품을 설계 및 제작하였다. 수증기 개질에 필요한 흡열 반응열은 복사 전열 방식의 metal fiber burner를 이용하여 공급하였다. 시스템 성능은 각 반응기의 일정한 공간속도 및 상압조건 하에서 개질기 반응온도 600-800℃에서 운전결과를 토대로 평가하였다. 최종시작품인 β+ 형에 있어서 개질가스 총유량은 6.5N㎥/h(H_2 농도: 74%, 건식 기준)이었으며 이때의 수증기 개질 반응기에 있어서 반응온도 및 GHSV는 각기 800℃, 1,950 h^-1이었다. 그리고 개질기 출구(혹은 스택 입구) 제한조건인 CO 농도를 맞추기 위하여 2단 직렬 선택적 산화 반응기(1단 : P_t, 2단 : Ru)를 구성하였으며, 1단과 2단 반응기 사이에 공냉식 핀(fin) 형 열교환기를 설치하여 1단 반응기에서 배출되는 개질가스의 온도를 저온(120℃)으로 제어 유지시킨 후 2단 PrOx 반응기로 공급함으로써 최종 개질가스 중의 일산화탄소의 농도를 10ppm 이하로 낮출 수 있었다. 연료 개질 효율(개질된 수소의 고발열량/리포머 및 버너에 공급된 천연가스의 고위발열량×100%)은 약 52% 정도로서 약간 낮은 편이며 이는 리포머 열공급을 위한 버너 연소열이 시스템 외부로 과도하게 배출되는 것에 기인하였다. Prototype 5 kW-class fuel processor based on steam reforming of natural gas with heat and system integration has been designed and fabricated for use in proton exchange membrane(PEM) fuel cell with residential applications. Endothermic heat for steam reforming has been supplied by radiation type metal fiber burner. The performance of the integrated system has been experimentally evaluated for the reformer temperature of 600-800℃ at constant GHSV of each reactor and atmospheric system pressure. The final product(β^= type) can produce the total gas flow of 6.5 6.5N㎥/h(H_2 conc.: 74%, dry basis) under reformer temperature and space velocities of 800℃, 1,950 h^-1, respectively and also remove CO concentration under 10 ppm by two series fin type packed beds employing Pt[λ2O_2/CO)=2.1] and Ru[λ(2O_2/CO)=3.5] catalysts with interstage cooling. The overall fuel processing efficiency of about 52% calculated by the total H_2 output after PrOx to total methane flow into the reformer and the burner based upon higher heating values is somewhat lower. This was mainly attributed from the fact that heat loss from the exhaust gas after supplying heat necessary for raising the reformer temperature by combustion of natural gas was excessively high.
Jung, You-Shick,Yoon, Wang-Lai,Seo, Yong-Seog,Rhee, Young-Woo Elsevier 2012 CATALYSIS COMMUNICATIONS - Vol.26 No.-
<P>Ni-Al<SUB>2</SUB>O<SUB>3</SUB> catalysts are prepared via the co-precipitation method using various precipitants: urea, Na<SUB>2</SUB>CO<SUB>3</SUB>, NaOH, K<SUB>2</SUB>CO<SUB>3</SUB>, KOH and NH<SUB>4</SUB>OH. The effects of the precipitants on the physicochemical properties and catalytic activities of the Ni-Al<SUB>2</SUB>O<SUB>3</SUB> catalysts are investigated. The Ni50-urea catalyst displays the largest specific surface area and the highest pore volume. This catalyst also exhibits the highest Ni dispersion and the largest Ni surface area. Ni50-urea catalyst prepared with urea as precipitant and Ni50-K<SUB>2</SUB>CO<SUB>3</SUB> catalyst prepared with K<SUB>2</SUB>CO<SUB>3</SUB> as precipitant exhibit high pore volumes and good catalytic activities for methane steam reforming. The Ni50-urea catalyst exhibits the best physicochemical properties and shows good catalytic activity and a strong resistance to electrolyte contamination.</P>
Lee, Deuk Ki,Hyun Baek, II,Lai Yoon, Wang Elsevier 2006 International journal of hydrogen energy Vol.31 No.5
<P><B>Abstract</B></P><P>A hybrid reaction system of catalytic methane steam reforming (MSR) and in situ non-catalytic removal of <SUB>CO2</SUB> by the carbonation of CaO to <SUB>CaCO3</SUB> in a moving bed reactor where reforming catalyst and CaO-based <SUB>CO2</SUB> acceptor in pellets move co-currently with gaseous reactants has been simulated through a mathematical model. The model has been developed at non-isothermal, non-adiabatic, and non-isobaric operating conditions assuming that the rate of the CaO carbonation in a local zone of the reactor bed is governed by kinetic limitation or by the <SUB>CO2</SUB> limitation in bulk gas phase. The effects of major operating parameters such as the feed rates of CaO and <SUB>CH4</SUB>, and the reactor bed temperature on steady-state behavior of the hybrid reaction in a moving bed reactor have been determined. It was revealed that the feed rate of CaO for a given feed rate of <SUB>CH4</SUB> should be optimized in order to maximize the utilization degree of CaO carbonated through the reactor while producing the reformed gas in the possible lowest concentration of <SUB>CO2</SUB> at a given temperature of reaction.</P>