• Title, Summary, Keyword: Reformer

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Numerical Study on Geometries and Operating Parameters of a Steam Reformer for Hydrogen Production (수소 생산을 위한 수증기 개질기의 형상 변화와 작동 조건에 대한 수치해석 연구)

  • Byun, Kang-Soo;Lee, Jae-Seong;Kim, Ho-Young
    • Journal of the Korean Society of Combustion
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    • v.16 no.3
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    • pp.1-11
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    • 2011
  • The main objective of this paper is to investigate characteristic of steam reformer at various geometries and operating conditions. In this paper, the steam reforming is studied by a numerical method and three dimensional simulations were used for effective analytical study. User - Defined Function (UDF) was used to simultaneously calculate reforming and combustion reaction. And the numerical model is validated with experimental results at the same operating conditions. In order to understand the relationship between operating conditions such as gas hourly space velocity(GHSV), mass flow rate of combustor inlet, various numerical investigations are carries out for various geometries. Numerical results show that cylindrical geometry is more effective than rectangular geometry for heat transfer to reactors and reforming efficiency. As mass flow rate of combustor inlet increase, reaction occurs more faster and temperature increase with each geometry. On the other hand, reaction and hydrogen conversion decrease as mass flow rate of reactor decreases.

Parametric Study of an Integrated Steam Methane Reformer with Top-Fired Combustor (통합 수증기 개질 시스템의 작동 조건에 대한 수치적 연구)

  • Noh, Jung-Hun;Jung, Hye-Mi;Kim, Donghee;Um, Sukkee
    • 한국신재생에너지학회:학술대회논문집
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    • pp.156.1-156.1
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    • 2011
  • It is of great importance to predict operating parameter characteristics of an integrated fuel processor by the increased life-time and system performance. In this study, computational analysis is performed to gain fundamental insights on transport phenomena and chemical reactions in reformer which consists of preheating, steam reforming, and water gas shift reaction beds. Also, a top-fired burner locates inside of the reforming system. The combustor is providing thermal energy necessary for the steam reforming bed which is a endothermic catalytic reactor. Two-dimensional numerical model of the integrated fuel processing system is introduced for the analysis of heat and mass transport phenomena as well as surface kinetics and catalytic process. A kinetic model was developed and then computational results were compared with the experimental data available in the literature. Subsequently, parameter study using the validated steam methane reforming model was conducted by considering operating parameters, i.e. steam to carbon ratio and temperature.

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NUMERICAL STUDY OF STREAM REFORMER AND PRECONVERTER FOR MCFC (MCFC용 개질기 및 프리컨버터의 수치연구)

  • Byun, Do-Hyun;Sohn, Chang-Hyun
    • Journal of computational fluids engineering
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    • v.16 no.1
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    • pp.42-47
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    • 2011
  • In this paper, various operating parameters of stream reforming process from methane in stream reformer and preconverter for MCFC is studied by numerical method. Commercial code is used to simulated the porous catalyst with user subroutine to model three dominant chemical reactions which are Stream Reforming(SR), Water-Gas Shift(WGS), and Direct Stram Reforming(DSR). The hydrogen production is tested with different wall temperature and different reactor shapes. The calculated results of the concentration of hydrogen in stream reformer are very well consistent with experimental results. This numerical study gives the design reactor wall temperature condition and size of reactor to satisfy the required fuel conversion.

A Study on the High Efficient Steam Reformer using Various Burner Types (다양한 형태의 버너를 이용한 수증기개질기의 고효율화 연구)

  • Lee, Myeong-Yong;Lee, Ji-Hong;Lee, Sang-Seok;Lee, Jin-Seok;Lee, Do-Hyung
    • Proceedings of the KSME Conference
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    • pp.2886-2891
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    • 2008
  • The purpose of this study is to develop a highly-efficient and compact steam reformer for PEMFC changing the burner types. For the purpose some of the Can type flat burners were adopted and the results were compared with 'O' company's typical cylinderical flat burner. We used commercial STAR-CD tools for numerical calculation. We found the optimum Can type STR burner and this type of burner was highly efficient comparing with typical burner.

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Development of a 50W Powered Ceramic Micro Reformer Equiped with PROX Reactor (PROX 반응기가 있는 50W급 세라믹재질의 소형 reformer 개발)

  • Chung C.H.;Kim W.J.;Oh J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.225-229
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    • 2005
  • We have designed micro-fuel processor system, which consists of a steam reforming area and a PROX(preferential oxidation) area. Micro-fuel processor system generates $H_2$ rich gas from a methanol. In our experiment, we have integrated micro-fuel processor system using low temperature cofired ceramics (LTCC) process because LTCC is superior to other materials principally due to their high thermal and chemical stability, simpler fabrication processes, and lower materials cost. Therefore, we have studied and integrated micro-fuel processor system containing embedded heaters, cavities, and 3D structures of micro-channel with LTCC. Also we have optimized the LTCC process.

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Numerical Analysis of dynamic behavior and steady state characteristics of methane autothernal reformer (메탄 자열 개질기의 동적 거동 및 정상 특성에 관한 수치적 연구)

  • Lee, Shin-Ku;Park, Joon-Guen;Bae, Joong-Myeon
    • 한국신재생에너지학회:학술대회논문집
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    • pp.5-8
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    • 2007
  • In this paper, numerical investigation has been carried out to study performance of methane autothermal reformer and dynamic behavior for light-off under various operating conditions. In order to simulate the given problems, numerical methods are incorporated using finite-volume method. In addition, porous medium approach is accepted because the catalytic phenomena occur in porous media. Also, start-up issue is significant in autothermal reformer although the reaction is marginally exothermic. Thus, in this study transient behavior has been also investigated to find out optimal operating conditions for start-up.

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Effect of various boundary conditions and geometries in steam reformer using numerical analysis (수치해석을 이용한 수증기 개질 반응기의 다양한 경계조건 및 형상의 영향)

  • Park, Joon-Guen;Lee, Shin-Ku;Lim, Sung-Kwang;Bae, Joong-Myeon
    • 한국신재생에너지학회:학술대회논문집
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    • pp.41-44
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    • 2007
  • Steam reforming reaction of natural gas is an important process for fuelcell commercialization. In this paper, steam reforming reaction is studied by numerical method. Pseudo-homogeneous model is incorporated for chemical reactions and one medium approach is used to take into account thermally equilibrium phenomena between catalyst and bulk gas. The model is validated with our experimental results under the same operating conditions. Because performance of reformer has relation to heat flux from wall, heat flux profiles was investigated by using Nusselt number. Value of Nusselt number in steam reformer is larger than one in channel, which does not have chemical reaction because steam reforming reaction is an endothermic reaction. When the difference of Nusselt number at the front and the rear is larger, performance is improved.

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Partial Insulation and Heating Tubes Configuration of Shell and Tube Steam Reformer at Medium Temperature (중온형 원통다관형 수증기 개질기의 부분단열 및 반경방향 분배 구조의 영향)

  • PARK, DAIN;YU, SANGSEOK
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.6
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    • pp.618-626
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    • 2017
  • Conventional high temperature reformers are not suitable for hybrid fuel cell systems that use waste heat as a heat source. So, development of a low temperature type reformer is needed. However, the analysis was conducted in two ways to increase the thermal efficiency, because of low reforming rate due to the low heat source. First, it is a way to ger thermal gain from the outside through partial insulation. In the case of one heat source tube and several heat source tubes, we analyzed the effect of partial heat insulation in some cases. Second, we found the most efficient arrangement of the heat source tubes by changing the location of the heat source tubes. The interpretation was carred out using the COMSOL Mutiphysics program.

A comparative study for steam-methane reforming reaction analysis model (수증기-메탄개질반응 해석모델의 비교연구)

  • Choi, Chong-Gun;Jung, Tae-Yong;Dong-Hoon, Shin;Nam, Jin-Hyn;Kim, Yong-Gyu
    • Proceedings of the KSME Conference
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    • pp.1997-2002
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    • 2007
  • The reformer is one of the most important chemical processes for the production of high purity hydrogen from fossil fuel. This study compares zero-dimensional model with CFD models for reaction analysis of methane-steam reformer. The zero-dimensional model is an empirical equation, however CFD model uses reactions of Arrhenius type. Because the reaction coefficients of the steam-methane catalytic reforming have not been reported before in the form of Arrhenius type, the present study aims to find the appropriate reaction coefficients. The used CFD code is Fluent 6.2 version. Several models are compared for the case of various operating temperature, mass of catalyst and steam to methane ratio.

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

  • Yoon, Sang-Ho;Kang, In-Yong;Bae, Joong-Myeon
    • Proceedings of the KSME Conference
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    • pp.2015-2020
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    • 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.

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