• Title, Summary, Keyword: Reformer

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A Study on Thermal and Mechanical Behaviors of Micro Reformer (마이크로 리포머의 열 및 역학적 거동 분석)

  • Hwang W.H.;Jang J.H.;Kil J.H.;Kim S.J.;Lee R.W.;Kim S.H.;Chung K.H.;Oh Y.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.235-239
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    • 2005
  • We analyzed the thermal and mechanical behaviors of micro reformer for the purpose of design verifications and modification of micro channels. The reformer designed for hydrogen generation from methanol is essential to PEM(Proton Exchange Membrane) type fuel cell. For the mobile applications, the size and the simplicity would be the most critical issues. We utilized silicon process for micro reformer to obtain the thickness thinner than 2 mm thick. We have used commercial simulation software, IDEAS, to analyze the thermal and mechanical characteristics of micro reformer structure. The heat generation rates of heaters, heat transfer rates, and fluid temperatures are derived from thermal equilibrium relation and these values were used for thermal boundary conditions. We also analyzed the thermal stresses, thermal deformations to examine the possibility of failure.

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Optimization of Fuel Processing Unit of Fuel Cell System using Six-Sigma Technique (Six-sigma 기법을 이용한 연료전지시스템 연료저리장치 최적화)

  • Chung, Kyung-Yong;Kim, Sun-Hoe
    • Journal of Digital Convergence
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    • v.10 no.2
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    • pp.225-229
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    • 2012
  • A reformer for a small fuel cell system is an apparatus which converts hydrocarbon fuel into hydrogen-rich gas. Among many indices of a reformer, the most crucial index of a reformer is CO concentration in the off-gas out of reformer which must be controled under 5ppm for the efficiency and performance of a system. This paper suggests the criteria of a reformer operation for the stability of a reformer in a fuel cell system by deducing crucial indices and improving processes. The six-sigma technique was applied to verify the optimum control and operation of a reformer of a fuel cell combined heat and power system. The result of temperature control of each parts of a reformer system is the concentration of CO which is the most important factor for the operation of a fuel cell system. The temperature of the parts of a reformer, MTS, LTS and Prox, were controled so that the concentration of CO.

An Experimental Study on Catalytic Reformer with Direct Spraying of Fuel and Water for SOFC (고체산화물 연료전지용 연료.물 직접 분무식 촉매 개질기에 관한 실험적 연구)

  • Lee, Dae-Keun;Dong, Sang-Geun;Yang, Je-Bok;Kim, Hak-Joo;Jung, Heon
    • 한국연소학회:학술대회논문집
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    • pp.260-265
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    • 2006
  • An experimental study on the catalytic reformer adopted in the auxiliary power unit system of solid oxide fuel cell was conducted. A 3-fluid nozzle, by which liquid fuel such as diesel, water and air are sprayed and uniformed mixed, was designed and used in this study. An electrically heated monolith inserted in the reformer was used for the vaporization of fuel and water in the transient state of reformer. The reformer uses the partial oxidizing reaction at the catalyst and the supply of water prevents the flame combustion in the spraying zone and lessens the deactivation of catalyst. The result showed that the reforming of liquid fuel can be started by the electrically heated monolith and the 3-fluid nozzle can give the uniform mixing of fuel, water and air. It was also found that the reformer fueled by n-hexadecane can make the reformate, at best, containing $H_2$ at 15.5% and CO at 11.5% that are used as fuel in the solid oxide fuel cell.

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Computational Fluid Dynamics Analysis of 25kW Plate Type Methane-steam Reformer (25kW급 평판형 메탄-수증기 개질기 열유동 전산해석)

  • Shin, Dong-Hoon;Seo, Hye-Gyung;Lim, Hee-Chun;Lee, Sang-Duk
    • 한국신재생에너지학회:학술대회논문집
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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

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Operating Characteristics on Coupling of Fuel-Cell System with Natural Gas Reformer (천연가스 개질기와 연계한 연료전지시스템의 운전특성)

  • Park, Se-Joon;Choi, Young-Sung;Hwang, Jong-Sun;Lee, Kyung-Sup
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.4
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    • pp.639-643
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    • 2009
  • A reformer, which produces hydrogen from natural gas, plays a major role for producing quality hydrogen to fuel-cell system. In this paper, fuel processor is designed to deliver hydrogen(75%) from the reformer to 200W fuel-cell system, and the electrical output power of the fuel-cells is examined by being injected different hydrogen concentrations to the system. We verified that the output power characteristics of the fuel-cells with 75% reformed hydrogen was lower about 7% than the case of pure hydrogen supplied. The type of reformer in this experiment takes SMR(Steam methane reforming) process, and the temperature variation characteristics of reforming process by reactions are examined in operation.

Numerical Study on operating conditions of Autothermal Reformer using natural gas (천연가스를 이용한 자열개질기의 운영조건에 대한 수치해석 연구)

  • Kim, Jinwook;Kim, Sangwoo;Park, Dalyung;Jeon, Sanghee;Lee, Dohyung
    • 한국신재생에너지학회:학술대회논문집
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    • pp.91.1-91.1
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    • 2010
  • The Reforming system is an effective method to generate hydrogen which uses for fuel cell system. The purpose of this study is to present characteristics of an autothermal reformer at various operating conditions and to investigate ideal conditions for reforming efficiency. Dominant chemical reactions are Full Combustion, Steam Reforming reaction, Water-Gas Shift reaction and Direct Steam Reforming reaction. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio, Steam to Carbon Ratio and Gas Hourly Space Velocity. Autothermal reformer is filled with catalysis of a packbed-bed type. Using numerical approach, we have investigated on various reaction conditions.

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The Effects of Combustion Parameters on the Characteristics of a Steam-Methane Reformer (연소 변수가 수증기-메탄 개질기의 특성에 미치는 영향)

  • Lee, Jae-Seong;Kim, Ho-Young
    • 한국연소학회:학술대회논문집
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    • pp.29-31
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    • 2012
  • The effects of combustion parameters on the characteristics of a steam-methane reformer. The reformer system was numerically simulated using a simplified two-dimensional axisymmetric model domain with an appropriate user-defined function. The fuel ratio, defined as the ratio of methane flow rate in the combustor to that in the reactor, was varied from 20 to 80%. The equivalence ratio was changed from 0.5 to 1.0. The results indicated that as the fuel ratio increased, the production rates of hydrogen and carbon monoxide increased, although their rates of increase diminished. In fact, at the highest heat supply rates, hydrogen production was actually slightly decreased. Simulations showed that equivalence ratio of 0.7 yielded the highest steam-methane mixture temperature despite a 43% higher air flow rate than the stoichiometric flow rate. This means that the production of hydrogen and carbon monoxide can be increased by adjusting the equivalence ratio, especially when the heat supply is insufficient.

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Study on the Characteristics of Methanol Steam Reformer Using Latent Heat of Steam (수증기의 잠열을 이용한 메탄올 수증기 개질기의 특성 연구)

  • CHEON, UKRAE;AHN, KANGSUB;SHIN, HYUNKHIL
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.1
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    • pp.19-24
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    • 2018
  • Fuel cells are used to generate electricity with a reformer. In particular, methanol has various advantages among the fuels for reformer. Methanol steam reformer devices can efficiently supply hydrogen to PEM fuel cell. This study investigated the optimal operation conditions of a methanol steam reforming process. For this purpose, aspen HYSYS was used for the optimization of reforming process. The optimal operating condition could be designed by setting independent variables such as temperature, pressure and steam to carbon ratio (SCR). The optimal temperature and steam to carbon ratio were $250-270^{\circ}C$ and 1.3-1.5, respectively. It is advantageous to operate at a pressure of 15-20 barg, considering the performance of the hydrogen purifier. In addition, a heat exchange network was designed to supply heat constantly to reformer through the latent heat of steam.

Thermal Flow Analysis of Operating Parameters in Autothermal Reformer (자열개질기의 운용조건에 따른 열유동 수치해석)

  • Park, Seung-Hwan;Kim, Jin-Wook;Park, Dal-Yung;Kim, Jae-Dong;Lee, Do-Hyung
    • The KSFM Journal of Fluid Machinery
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    • v.14 no.6
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    • pp.61-67
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    • 2011
  • The study is to analyze the chemical and heat-flow reactions in the hydrogen generation unit(autothermal reformer), using computational numerical tools. Autothermal reformer(ATR) is involved in complex chemical reaction, mass and heat transfer due to exothermic and endothermic reactions. Therefore it is necessary to reveal the effects of various operation parameters and geometries on the ATR performance by using numerical analysis. Numerical analysis needs to dominant chemical reactions that includes Full Combustion(FC) reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction and Direct Steam Reforming(DSR) reaction. The objective of the study is to improve theoretically the reformer design capability for the goal of high hydrogen production in the autothermal reformer using methane. Hydrogen production reached maximum in a certain value of Oxygen to Carbon Ratio(OCR) or Steam to Carbon Ratio(SCR). When the longitudinal distance to dimeter ratio(L/D) is increased, hydrogen production increases.

Studies on a Micro Reformer System with a Two-staged Microcombustor (초소형 2단 연소기를 이용한 리포머 시스템에 관한 연구)

  • Kim, Ki-Baek;Lee, Jung-Hak;Kwon, Oh-Chae
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.3
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    • pp.217-225
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    • 2008
  • A new micro reformer system consisted of a micro reformer, a microcombustor and a micro evaporator was studied experimentally and computationally. In order to satisfy the primary requirements for designing the microcombustor integrated with a micro evaporator, i.e. stable burning in a small confinement and maximum heat transfer through a wall, the present microcombustor is simply cylindrical to be easily fabricated but two-staged (expanding downstream) to feasibly control ignition and stable burning. Results show that the aspect ratio and wall thickness of the microcombustor substantially affect ignition and thermal characteristics. For the optimized design conditions, a premixed microflame was easily ignited in the expanded second stage combustor, moved into the smaller first stage combustor, and finally stabilized therein. A micro reformer system integrated with a modified microcombustor based on the optimized design condition was fabricated. For a typical operating condition, the designed micro reformer system produced 22.3 sccm hydrogen (3.61 W in LHV) in an overall efficiency of 12%.