• Title, Summary, Keyword: Fuel reforming

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Performance of Solid Oxide Fuel Cells with Direct Internal Reforming of Methane

  • Kim, Young Jin;Lim, Hyung-Tae
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.325-330
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    • 2015
  • Performance of solid oxide fuel cells (SOFCs), in comparison with that under hydrogen fuel, were investigated under direct internal reforming conditions. Anode supported cells were fabricated with an Ni+YSZ anode, YSZ electrolyte, and LSM+YSZ cathode for the present work. Measurements of I-V curves and impedance were conducted with S/C (steam to carbon) ratio of ~ 2 at $800^{\circ}C$. The outlet gas was analyzed using gas chromatography under open circuit condition; the methane conversion rate was calculated and found to be ~ 90% in the case of low flow rate of methane and steam. Power density values were comparable for both cases (hydrogen fuel and internal steam reforming of methane), and in the latter case the cell performance was improved, with a decrease in the flow rate of methane with steam, because of the higher conversion rate. The present work indicates that the short-term performance of SOFCs with conventional Ni+YSZ anodes, in comparison with that under hydrogen fuel, is acceptable under internal reforming condition with the optimized fuel flow rate and S/C ratio.

Activity test of post-reforming catalyst for removing the ethylene in diesel ATR reformate (디젤 자열개질 가스 내 포함된 $C_2H_4$ 제거를 위한 후개질기 촉매 활성 실험)

  • Yoon, Sang-Ho;Bae, Joong-Myeon;Lee, Sang-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • pp.218-221
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    • 2009
  • Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

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Study on hydrocarbon reforming using microchannel catalysts (마이크로 채널을 이용한 탄화수소 연료개질에 관한 연구)

  • Bae, Gyu-Jong;Park, Joon-Geun;Bae, Joong-Myeon
    • 한국신재생에너지학회:학술대회논문집
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    • pp.33-36
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    • 2007
  • Currently, many structured catalysts using microchannel are researched to apply to fuel reforming. In this paper, ceramic monolith and metal mesh as structured catalysts are investigated for catalytic autothermal reforming. When GHSV increases, each structured catalyst has better performances(hydrogen production, fuel conversion) than packed bed catalyst for autothermal reforming. The major causes seem to be the elevated heat and mass transfer, gas phase reaction and redistribution of packed bed due to high pressure drop.

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Life Cycle Assessment for Hydrogen Production Method using Stream Reforming of Naphtha (Naphtha의 stream reforming에 의한 수소제조방법에 대한 전과정평가)

  • Park, Hee-Il;Kim, Ik;Lee, Byung-Kwon;Hur, Tak
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.1
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    • pp.3-12
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    • 2002
  • In this study, it achieved life cycle assessment to estimate environmental performance for naphtha steam reforming that account for the production over 50% of total hydrogen output. Although hydrogen dosen't emit air emissions, especially, $CO_2$, a large of $CO_2$ is emitted in hydrogen production process. In the result of this study, it ascertained the truth that $CO_2$ is emitted at the rate of $6.3kg/kgH_2$ and that result from steam reforming reaction and use of fossil fuel in hydrogen manufacturing process. Above all, 57% of total $CO_2$ emissions is emitted in process of steam reforming of naphtha and so it knew that the principle of steam reforming is key issue in aspect to environment. Also, it compared hydrogen by fuel of fuel cell vehicle with gasoline fuel of general gasoline vehicle to analyze relative environment of hydrogen for fossil fuel during the life cycle. As the result, it might be difficult in improvement of environment because $CO_2$ emissions during the hydrogen manufacturing process is nearly the same with that during the use of gasoline.

kW-class Diesel Autothermal Reformer with Microchannel Catalyst for Solid Oxide Fuel Cell System (고체산화물 연료전지 시스템을 위한 kW급 마이크로채널 촉매 디젤 자열 개질기)

  • Yoon, Sang-Ho;Kang, In-Yong;Bae, Gyu-Jong;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.7
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    • pp.558-565
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    • 2008
  • Solid oxide fuel cell(SOFC) has a higher fuel flexibility than low temperature fuel cells, such as polymer electrolyte fuel cell(PEMFC) and phosphoric acid fuel cell(PAFC). SOFCs also use CO and $CH_4$ as a fuel, because SOFCs are hot enough to allow the CH4 steam reformation(SR) reaction and water-gas shift(WGS) reaction occur within the SOFC stack itself. Diesel is a good candidate for SOFC system fuel because diesel reformate gas include a higher degree of CO and $CH_4$ concentration than other hydrocarbon(methane, butane, etc.) reformate gas. Selection of catalyst for autothermalr reforming of diesel was performed in this paper, and characteristics of reforming performance between packed-bed and microchannel catalyst are compared for SOFC system. The mesh-typed microchannel catalyst also investigated for diesel ATR operation for 1kW-class SOFC system. 1kW-class diesel microchannel ATR was continuously operated about 30 hours and its reforming efficiency was achieved nearly 55%.

Preparation of perovskite-based catalysts and fuel injection system for high durability of diesel reforming (디젤 개질을 위한 페로브스카이트 구조 촉매와 연료주입 시스템의 개발)

  • Rhee, Junki;Park, Sangsun;Shul, Yong-Gun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.115.2-115.2
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    • 2010
  • Autothermal reforming(ATR) processes of hydrocarbon liquids such as diesel fuels are spotlighted as methods to produce hydrogen for Fuel cell. However, the use of heavy hydrocarbons as feedstocks for hydrogen production causes some problems which increase the catalyst deactivation by the carbon deposition. Coking can be inhibited by increasing the water dissociation on the catalyst surface. This results in catastrophic failure of whole system. Performance degradation of diesel autothermal reforming leads to increase of undesirable hydrocarbons at reformed gases and subsequently decrease the performance. In this study, perovskite-based catalysts were investigated as alternatives to substitute the noble metal catalyst for the ATR of diesel. The investigated perovskite structure was based on LaCrO3. and metals were added at the A-site to enhance oxygen ion mobility, transition metals were doped on the B-site to enhance the reformation. Substituted Lanthanum chromium perovskite were made by aqueous combustion synthesis, which can produce high surface area. And for the homogeneous fuel supply, we made ultrasonic injection system for reforming. We compared durability of evaporation system and ultrasonic system for fuel injection.

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Degradation Comparison of Hydrogen and Internally Reformed Methane-Fueled Solid Oxide Fuel Cells

  • Kim, Young Jin;Lee, Hyun Mi;Lim, Hyung-Tae
    • Journal of the Korean Ceramic Society
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    • v.53 no.5
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    • pp.483-488
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    • 2016
  • Anode supported solid oxide fuel cells (SOFCs), consisting of Ni+YSZ anode, YSZ electrolyte, and LSM+YSZ cathode, were fabricated and constant current tested with direct internal reforming of methane (steam to carbon ratio ~ 2) as well as hydrogen fuel at $800^{\circ}C$. The cell, operated under direct internal reforming conditions, showed relatively rapid degradation (~ 1.6 % voltage drop) for 95 h; the cells with hydrogen fuel operated stably for 170 h. Power density and impedance spectra were also measured before and after the tests, and post-test analyses were conducted on the anode parts using SEM / EDS. The results indicate that the performance degradation of the cell operated with internal reforming can be attributed to carbon depositions on the anode, which increase the resistance against anode gas transport and deactivate the Ni catalyst. Thus, the present study shows that direct internal reforming SOFCs cannot be stably operated even under the condition of S/C ratio of ~ 2, probably due to non-uniform mixture (methane and steam) gas flow.

Study on n-Butane Autothermal Reforming for Portable Fuel Cell (휴대용 연료전지를 위한 부탄 자열개질에 관한 연구)

  • Bae, Gyu-Jong;Kang, In-Young;Lim, Sung-Kwang;Bae, Joong-Myeon;Kim, Ju-Yong;Lee, Chan-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.11
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    • pp.1123-1130
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    • 2006
  • This study discusses about research efforts of hydrogen generation from hydrocarbon(e.g., diesel, gasoline, natural gas, and LPG), especially, butane reforming by using Autothermal Reforming Reaction (ATR) technology. Several catalysts were selected for butane ATR. Thermodynamic reactor conditions (temperature, $O_2$/C, S/C) are varied and reforming characteristics of 2 catalysts (Pt and Rh on ceramic supports) and 1 commercial catalyst (FCR-HC35) have been examined. To understand reaction behaviors in an ATR reactor comprehensively, temperature profiles of reactor were observed. By mass transfer limitation, fuel conversion decreases when GHSV increases. Significant temperature variation along the reactor was observed and it was mainly due reaction kinetics difference between exothermic oxidation and endothermic reforming reaction.

Numerical Study on Correlation between Operating Parameters and Reforming Efficiency for a Methane Autothermal Reformer (천연가스 자열개질기를 위한 작동조건과 개질효율의 상관관계에 대한 수치해석 연구)

  • Park, Joon-Guen;Lee, Shin-Ku;Lim, Sung-Kwang;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.8
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    • pp.636-644
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    • 2008
  • The objective of this paper is to investigate characteristics of an autothermal reformer at various operating conditions. Numerical method has been used, and simulation model has been developed for the analysis. Pseudo-homogeneous model is incorporated because the reactor is filled with catalysts of a packed-bed type. Dominant chemical reactions are Full Combustion reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction, and Direct Steam Reforming(DSR) reaction. Simulation results are compared with experimental results for code validation. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio(OCR), Steam to Carbon Ratio(SCR), and Gas Hourly Space Velocity(GHSV). Temperature at the reactor center, fuel conversion, species at the reformer outlet, and reforming efficiency are shown as simulation results. SR reaction rate is improved by increased inlet temperature. Reforming efficiency and fuel conversion reached the maximum at 0.7 of OCR. SR reaction and WGS reaction are activated as SCR increases. When GHSV is increased, reforming efficiency increases but pressure drop from the increased GHSV may decrease the system efficiency.

Characteristics of LPG Fuel Reforming using Plasma Technology (플라즈마를 이용한 LPG연료 개질 특성연구)

  • Kim, Changup
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.1
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    • pp.1-7
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    • 2015
  • In this study, characteristics of reforming process of automotive liquefied petroleum gas (LPG) fuel using plasma reactor are investigated. Because plasma reformer technology has advantages of a fast start-up and wide fuel/oxidizer ratio of operation, and reactor size is smaller and more simple compared to typical combustor and catalytic reactor, plasma reforming is suitable to the on-board vehicle reformer. To evaluate the characteristics of the reforming process, parametric effect of $O_2/C$ ratios, reactant flow rate and metal form on the process were investigated. In the test of varying $O_2/C$ ratio from partial oxidation to stoichiometry combustion, conversion of LPG was increased but selectivity of $H_2$ decreased. The optimum condition of $O_2/C$ ratio for the highest $H_2$ yield was determined to be around 1.0 for 20~50 lpm, and 1.35 for 100 lpm. Specific energy density (SED) was major factor in reforming process and higher SED leads to higher $H_2$ yield. And metal form in the reformer increased $H_2$ yield of about 34 % as compared to the case of no metal form. The result can be a guide to map optimal condition of reforming process.