• 제목, 요약, 키워드: Fuel reforming

검색결과 293건 처리시간 0.044초

Low Temperature Methane Steam Reforming for Hydrogen Production for Fuel Cells

  • Roh, Hyun-Seog;Jun, Ki-Won
    • Bulletin of the Korean Chemical Society
    • /
    • v.30 no.1
    • /
    • pp.153-156
    • /
    • 2009
  • Low temperature methane steam reforming to produce $H_2$ for fuel cells has been calculated thermodynamically considering both heat loss of the reformer and unreacted $H_2$ in fuel cell stack. According to the thermodynamic equilibrium analysis, it is possible to operate methane steam reforming at low temperatures. A scheme for the low temperature methane steam reforming to produce $H_2$ for fuel cells by burning both unconverted $CH_4$ and $H_2$ to supply the heat for steam methane reforming has been proposed. The calculated value of the heat balance temperature is strongly dependent upon the amount of unreacted $H_2$ and heat loss of the reformer. If unreacted $H_2$ increases, less methane is required because unreacted $H_2$ can be burned to supply the heat. As a consequence, it is suitable to increase the reaction temperature for getting higher $CH_4$ conversion and more $H_2$ for fuel cell stack. If heat loss increases from the reformer, it is necessary to supply more heat for the endothermic methane steam reforming reaction from burning unconverted $CH_4$, resulting in decreasing the reforming temperature. Experimentally, it has been confirmed that low temperature methane steam reforming is possible with stable activity.

디젤연료의 미립화에 따른 자열개질 반응특성에 관한 연구 (Atomization Effects of Diesel on Autothermal Reforming Reaction)

  • 배중면;윤상호;강인용
    • 한국분무공학회지
    • /
    • v.11 no.4
    • /
    • pp.234-243
    • /
    • 2006
  • Diesel autothermal reforming (ATR) is a chemical process to produce hydrogen for fuel cell applications. Several previous studies were carried out to identify technical issues in diesel reforming. It is hard to vaporize diesel due to its high boiling points. Liquid droplets of diesel result in inhomogeneous fuel mixing with other reactants such as $O_2\;and\;H_2O$, which leads to reduce the reforming efficiency and make undesired coke in reactor. To solve the fuel delivery issue, we applied an ultrasonic device as a fuel injection system. Ultrasonic injector (UI) remarkably enhanced the reforming efficiency. This paper will present the reforming results using UI. And we will discuss about atomization effects of diesel on autothermal reforming reaction.

  • PDF

SOFC 시스템용 디젤 자열개질기 운전을 위한 기초 연구 (Experimental study on operation of diesel autothermal reformer for SOFC system)

  • 윤상호;강인용;배중면
    • 대한기계학회:학술대회논문집
    • /
    • /
    • pp.2015-2020
    • /
    • 2007
  • Diesel is an excellent candidate fuel for fuel cell applications due to its high hydrogen density and well-established infrastructure. But, it is hard to guarantee desirable performance of diesel reformer because diesel reforming has several problems such as sulfur poisoning of catalyst and carbon deposition. We have been focusing on diesel autothermal reforming(ATR) for substantial period. It is reported that ATR of diesel has several technical advantages such as relatively high efficiency and fuel conversion compared to steam reforming(SR) and partial oxidation(POX). In this paper, we investigate characteristics of diesel reforming under various ratios of reactants(oxygen to carbon ratio, steam to carbon ratio) for improvement of reforming performances(high reforming efficiency, high fuel conversion, low carbon deposition). We also exhibit calculated heat balance of autothermal reformer at each condition to help thermal management of SOFC system.

  • PDF

촉매 연소를 열원으로 한 수증기-메탄개질반응 전산유체해석 (Numerical Analysis of Steam-methane Reforming Reaction for Hydrogen Generation using Catalytic Combustion)

  • 이정섭;이강훈;유상석;안국영;강상규
    • 한국수소및신에너지학회논문집
    • /
    • v.24 no.2
    • /
    • pp.113-120
    • /
    • 2013
  • A steam reformer is a chemical reactor to produce high purity hydrogen from fossil fuel. In the steam reformer, since endothermic steam reforming is heated by exothermic combustion of fossil fuel, the heat transfer between two reaction zones dominates conversion of fossil fuel to hydrogen. Steam Reforming is complex chemical reaction, mass and heat transfer due to the exothermic methane/air combustion reaction and the endothermic steam reforming reaction. Typically, a steam reformer employs burner to supply appropriate heat for endothermic steam reforming reaction which reduces system efficiency. In this study, the heat of steam reforming reaction is provided by anode-off gas combustion of stationary fuel cell. This paper presents a optimization of heat transfer effect and average temperature of cross-section using two-dimensional models of a coaxial cylindrical reactor, and analysis three-dimensional models of a coaxial cylindrical steam reformer with chemical reaction. Numerical analysis needs to dominant chemical reaction that are assumed as a Steam Reforming (SR) reaction, a Water-Gas Shift (WGS) reaction, and a Direct Steam Reforming(DSR) reaction. The major parameters of analysis are temperature, fuel conversion and heat flux in the coaxial reactor.

PEM 연료전지 및 하이브리드 시스템의 설계변수 해석 (Design Parametric Analysis of PEM Fuel Cell and Hybrid Systems)

  • 유병준;이영덕;안국영;김동섭
    • 대한기계학회논문집B
    • /
    • v.31 no.5
    • /
    • pp.448-456
    • /
    • 2007
  • Performance of PEM fuel cell systems and hybrid systems combining a PEMFC with a gas turbine have been evaluated. Two different reforming methods(steam reforming and autothermal reforming) were considered. Performances of fuel cell systems with two reforming methods were compared and effects of various design parameters on the system performance were investigated. Configurations of PEM fuel cell systems with two reforming methods have been revised to accommodate a gas turbine, resulting in PEMFC/GT hybrid systems. Performance of the hybrid systems were analyzed and compared with those of PEM systems. Influences of major design parameters on the hybrid system performance were also investigated.

메탄 내부개질 반응을 통한 고체산화물 연료전지의 탄소침적 억제에 관한 연구 (A Study on the Suppression of Carbon Deposition in Solid Oxide Fuel Cells Through Methane Internal Reforming)

  • 강윤혁;임성광;유영성;박진우;배중면
    • 대한기계학회논문집B
    • /
    • v.31 no.5
    • /
    • pp.473-481
    • /
    • 2007
  • Compared to other types of fuel cells, SOFC has advantages like a wide output range and the direct use of hydrocarbon fuel without the process of external reforming. Particularly because the direct use of fuel without reforming reaction is closely linked to overall system efficiency, it is a very attractive advantage. We tried the operation with methane. However, although methane has a small number of carbons compared to other hydrocarbon fuels, our experiment found the deposition of carbon on the surface of the SOFC electrode. To overcome the problem, we tried the operation through activating internal reforming. The reason that internal reforming was possible was that SOFC runs at high temperature compared to other fuel cells and its electrode is made of Ni, which functions as a catalyst favorable for steam reforming.

The developments of heavy hydrocarbon reformer for SOFC

  • 배중면
    • 한국재료학회:학술대회논문집
    • /
    • /
    • pp.58.2-58.2
    • /
    • 2012
  • Heavy hydrocarbon reforming is a core technology for "Dirty energy smart". Heavy hydrocarbons are components of fossil fuels, biomass, coke oven gas and etc. Heavy hydrocarbon reforming converts the fuels into $H_2$-rich syngas. And then $H_2$-rich syngas is used for the production of electricity, synthetic fuels and petrochemicals. Energy can be used efficiently and obtained from various sources by using $H_2$-rich syngas from heavy hydrocarbon reforming. Especially, the key point of "Dirty energy smart" is using "dirty fuel" which is wasted in an inefficient way. New energy conversion laboratory of KAIST has been researched diesel reforming for solid oxide fuel cell (SOFC) as a part of "Dirty energy smart". Diesel is heavy hydrocarbon fuels which has higher carbon number than natural gas, kerosene and gasoline. Diesel reforming has difficulties due to the evaporation of fuels and coke formation. Nevertheless, diesel reforming technology is directly applied to "Dirty fuel" because diesel has the similar chemical properties with "Dirty fuel". On the other hand, SOFC has advantages on high efficiency and wasted heat recovery. Nippon oil Co. of Japan recently commercializes 700We class SOFC system using city gas. Considering the market situation, the development of diesel reformer has a great ripple effect. SOFC system can be applied to auxiliary power unit and distributed power generation. In addition, "Dirty energy smart" can be realized by applying diesel reforming technology to "Dirty fuel". As well as material developments, multidirectional approaches are required to reform heavy hydrocarbon fuels and use $H_2$-rich gas in SOFC. Gd doped ceria (CGO, $Ce_{1-x}Gd_xO_{2-y}$) has been researched for not only electrolyte materials but also catalysts supports. In addition, catalysts infiltrated electrode over porous $La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2}O_3-{\delta}$ and catalyst deposition at three phase boundary are being investigated to improve the performance of SOFC. On the other hand, nozzle for diesel atomization and post-reforming for light-hydrocarbons removal are examples of solving material problems in multidirectional approaches. Likewise, multidirectional approaches are necessary to realize "Dirty energy smart" like reforming "Dirty fuel" for SOFC.

  • PDF

연료 다변화에 따른 용융 탄산염 연료전지 시스템 운전 특성 (Operating Characteristics of MCFC System on the Diversification of Fuel)

  • 임석연;성용욱;한재영;유상석
    • 한국수소및신에너지학회논문집
    • /
    • v.26 no.2
    • /
    • pp.156-163
    • /
    • 2015
  • The fuel cells have been investigated in the applications of marine as the high efficient and eco-friendly power generating systems. In this study, modeling of IR Type molten carbonate fuel cell (Internal Reforming Type molten carbonate fuel cell) has been developed to analyze the feasibility of thermal energy utilization. The model is developed under Aspen plus and used for the study of system performances over regarding fuel types. The simulation results show that the efficiency of MCFC system based on NG fuel is the highest. Also, it is also verified that the steam reforming is suitable as pre-reforming for diesel fuel.

자립형 $1kW_e$ 액체 연료 개질기 운전에 관한 연구 (Experimental study on self-sustaied $1kW_e$ liquid fuel reforming operation)

  • 윤상호;배규종;배중면
    • 한국신재생에너지학회:학술대회논문집
    • /
    • /
    • pp.503-506
    • /
    • 2008
  • Liquid hydrocarbon fuels, such as gasoline, kerosene, diesel and JP 8, can be good candidates for SOFC (solid oxide fuel cell) system fuel due to their high hydrogen density. Autothermal reforming (ATR) is suitable for liquid hydrocarbon fuel reforming because oxygen can decompose the aromatics in liquid fuel and steam can suppress the carbon deposition during catalytic reaction. The advantage of ATR is that it has a simple system construction due to exothermicity of ATR reaction. We control the exothermicity of reaction, make the reaction possible design a self-sustaining ATR reactor. A self-sustained 1kW-class kerosene autothermal reformer is introduced in this paper. The 1kW-class kerosene reformer was continuously operated for about 140 hours without degradation of reforming performance.

  • PDF

1 kW 고체산화물 연료전지 스택의 내부개질 특성 연구 (Study on Internal Reforming Characteristic of 1 kW Solid Oxide Fuel Cell Stack)

  • 최영재;안진수;이인성;배홍열;문지웅;이종규
    • 한국수소및신에너지학회논문집
    • /
    • v.28 no.4
    • /
    • pp.377-383
    • /
    • 2017
  • This paper presents the performance characteristics of a 1 kW solid oxide fuel cell (SOFC) stack under various internal reforming and fuel utilization conditions. The Research Institute of Industrial Science & Technology (RIST) developed the 9-cell stack using a $20{\times}20cm^2$ anode supported planar cell with an active area of $324cm^2$. In this work, current-voltage characteristic test, fuel utilization test, continuous operation, and internal reforming test were carried out sequentially for 765 hours at a furnace temperature of $700^{\circ}C$. The influence of fuel utilization and internal reforming on the stack performance was analyzed. When the 1 kW stack was tested at a current of 145.8 A with a corresponding fuel utilization of 50-70% (internal reforming of 50%) and air utilization of 27%, the stack power was approximately 1.062-1.079 kW. Under continuous operation conditions, performance degradation rate was 2.16%/kh for 664 hours. The internal reforming characteristics of the stack were measured at a current of 145.8. A with a corresponding fuel utilization of 60-75%(internal reforming of 50-80%) and air utilization of 27%. As fuel utilization and internal reforming ratio increased, the stack power was decreased. The stack power change due to the internal reforming ratio difference was decreased with increasing fuel utilization.