• 제목/요약/키워드: methane steam reforming

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마이크로채널 메탄 수증기 개질 반응기의 열 및 물질 전달 특성에 관한 수치해석 연구 (Numerical Study of Heat and Mass Transfer Characteristics in Microchannel Steam Methane Reforming Reactor)

  • 전승원;이규정;조연화;문동주
    • 대한기계학회논문집B
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    • 제36권9호
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    • pp.885-894
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    • 2012
  • 마이크로채널 메탄 수증기 개질 반응기의 열 및 물질 전달 특성을 이해하기 위한 수치해석 연구를 수행하였다. Rh-촉매의 메탄 수증기 개질 반응과 Pt-촉매의 메탄 연소 반응을 함께 모델링하였다. 화학 반응의 반응 속도를 해석 모델에 적용하였다. 접촉시간, 평행류 대향류 등 유동 패턴, 채널 크기 등이 개질 성능과 온도 분포에 미치는 영향을 관찰하였다. 평행류와 대향류는 서로 반대되는 온도 분포를 갖게 되고, 그로 인해 서로 다른 반응 속도와 화학종 몰분율을 나타낸다. 접촉시간이 짧아지고 채널 크기가 증가할수록 촉매층과 혼합물 유동 사이의 물질 전달이 제한되어 개질 성능은 감소하게 된다.

매립지가스(LFG)로부터 합성가스 제조시 반응조건에 따른 수율에 미치는 연구 (A Effect of Reaction Conditions on Syngas Yield for the Preparation of Syngas from Landfill Gas)

  • 조욱상;최경돈;백영순
    • 한국수소및신에너지학회논문집
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    • 제26권5호
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    • pp.477-483
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    • 2015
  • LFG (Land-Fill Gas) includes components of $CH_4$, $CO_2$, $O_2$, $N_2$, and water. The preparation of synthesis gas from LFG as a DME (Dimethyl Ether) feedstock was studied by methane reforming of $CO_2$, $O_2$ and steam over $NiO-MgO-CeO_2/Al_2O_3$ catalyst. Our experiments were performed to investigate the effects of methane conversion and syngas yield on the amount of LFG components over $NiO-MgO-CeO_2/Al_2O_3$ catalyst. Results were obtained through the methan reforming experiments at the temperature of $900^{\circ}C$ and GHSV of 8,800. The results were as following; it has generally shown that syngas yield increase with the increase of oxygen and steam amounts and then decrease. Highly methane conversion of above 98% and syngas yield of approximately 60% were obtained in the feed of gas composition flow-rate of 243ml/min of $CH_4$, 241ml/min of $CO_2$, 195ml/min of $O_2$, 48ml/min of $N_2$, and 450ml/min of steam, respectively, under reactor pressure of 1 bar for 200 hrs of reaction time. Also, it was shown that catalyst deactivation by coke formation was reduced by excessively adding oxygen and steam as an oxidizer of the methane reforming.

메탄 수증기 개질반응기에서 연소, 열전달 및 개질반응 특성 연구 (Numerical Investigation on Combustion, Heat Transfer and Reforming Reaction for Methane Steam Reformer)

  • 서용석;서동주;서유택;윤왕래
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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    • pp.50-57
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    • 2005
  • The aim of this study is to numerically investigate a compact reformer system currently under development and to design a better reforming system with more efficient heat transfer and reforming reactions. Numerical models were established separately for both the combustion part and the reforming reaction part. A comparison between the calculation results and experimental data showed that the concentration of the reformate at the exit of the reforming system was in good agreement with the measured data, but for the temperature at the exit little difference between them was found. After checking the validity of the numerical models, the heat transfer between the combustion gas and reforming catalysts was estimated and the behavior of the catalyst bed was investigated as a function of the operation parameters.

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촉매유효도 상관식에 기반한 마이크로 채널형 수증기/메탄 개질기의 효율적인 전산유체역학 해석모델 (Efficient Computational Fluid Dynamics Model for Microchannel-Type Steam/Methane Reformers with Nickel Washcoat Catalyst Layers Based on Effectiveness Factor Correlations)

  • 오윤석;정아름;남진현
    • 한국수소및신에너지학회논문집
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    • 제33권6호
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    • pp.749-760
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    • 2022
  • An efficient computational fluid dynamics model was proposed for simulating microchannel-type steam/methane reformers with thin washcoat catalyst layers. In this model, by using the effectiveness factor correlations, the overall reaction rate that occurs in the washcoat catalyst layer could be accurately estimated without performing the detailed calculation of heat transfer, mass transfer, and reforming reactions therein. The accuracy of the proposed model was validated by solving a microchannel-type reformer, once by fully considering the complex steam/methane reforming (SMR) process inside the washcoat layer and again by simplifying the SMR calculation using the effectiveness factor correlations. Finally, parametric studies were conducted to investigate the effects of operating conditions on the SMR performance.

글리세롤로부터 수증기 개질에 의한 수소 생산공정의 모델링, 시뮬레이션 및 최적화 (Modeling, Simulation and Optimization of Hydrogen Production Process from Glycerol using Steam Reforming)

  • 박정필;조성현;이승환;문동주;김태옥;신동일
    • Korean Chemical Engineering Research
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    • 제52권6호
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    • pp.727-735
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    • 2014
  • 본 연구에서는 바이오디젤 생산의 부산물인 글리세롤로부터 수증기 개질(Steam Reforming, SR) 반응을 통해 수소를 생산하는 공정의 모델링과 모사 및 최적화를 수행했다. 글리세롤을 이용한 수소 생산 방법은 기존의 수소 생산방법인 메탄의 수증기 개질법(Steam Methane Reforming, SMR)을 대체할 수 있는 새로운 방법으로 세계 여러 곳에서 연구가 진행 중이다. 글리세롤과 수증기의 기체 혼합물을 고온의 반응기 내에서 개질시켜 합성가스(CO, $H_2$)를 생산하고, 합성가스에 포함된 일산화탄소를 수성 가스 전화 반응(Water-Gas Shift, WGS)을 통해 수증기와 반응시켜 수소를 생성하고, 최종적으로 Pressure Swing Adsorption (PSA) 공정을 통하여 이산화탄소와 수소를 분리하여 정제된 수소를 얻는다. 공정시뮬레이션 프로그램인 UniSim을 이용하여 시뮬레이션을 진행하였으며, 열효율 개선을 실시하여 운전 비용을 절감하고자 하였다. 기존 연구인 미국 DOE와 독일 Linde의 글리세롤 이용 수소 생산공정과 수율 비교를 진행하였고, 수소 에너지 인프라 구축에 기여하기 위한 최적의 생산방법을 제안하였다.

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

  • 노정훈;정혜미;김동희;엄석기
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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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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천연가스로부터 수소를 생산하기 위한 수증기 개질기의 작동조건과 형상에 대한 수치해석 연구 (Numerical Study on Operating Parameters and Shapes of a Steam Reformer for Hydrogen Production from Methane)

  • 박준근;이신구;임성광;배중면
    • 대한기계학회논문집B
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    • 제33권1호
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    • pp.60-68
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    • 2009
  • The steam reformer for hydrogen production from methane is studied by a numerical method. Langmuir- Hinshelwood model is incorporated for catalytic surface reactions, and the pseudo-homogeneous model is used to take into account local equilibrium phenomena between a catalyst and bulk gas. Dominant chemical reactions are Steam Reforming (SR) reaction, Water-Gas Shift (WGS) reaction, and Direct Steam Reforming (DSR) reaction. The numerical results are validated with experimental results at the same operating conditions. Using the validated code, parametric study has been numerically performed in view of the steam reformer performance. As increasing a wall temperature, the fuel conversion increases due to the high heat transfer rate. When Steam to Carbon Ratio (SCR) increases, the concentration of carbon monoxide decreases since WGS reaction becomes more active. When increasing Gas Hourly Space Velocity (GHSV), the fuel conversion decreases due to the heat transfer limitation and the low residence time. The reactor shape effects are also investigated. The length and radius of cylindrical reactors are changed at the same catalyst volume. The longer steam reformer is, the better steam reformer performs. However, system energy efficiency decreases due to the large pressure drop.

마이크로웨이브 수용체 가열을 통한 바이오가스 개질 (Biogas Reforming through Microwave Receptor Heating)

  • 전영남;안준
    • 신재생에너지
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    • 제20권1호
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    • pp.126-134
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    • 2024
  • Biogas, composed mainly of methane (CH4) and carbon dioxide (CO2), is a renewable gas that can serve as an alternative energy source. In this study, we developed a new microwave reformer and analyzed its reforming characteristics. We observed that higher temperatures of the microwave receptor led to increased reforming efficiency. By supplying appropriate amounts of methane and steam, we could prevent carbon generated from the thermal decomposition reaction of carbon dioxide from depositing on the catalytic active layer, thus avoiding the inhibition of catalytic activity. Hydrogen generation was enhanced when maintaining the biogas ratio and steam supply at adequate levels. Increasing the SiC ratio in the receptor improved the uniformity of temperature distribution and growth rate, resulting in higher conversion rates of the reforming process.

Solar Simulator를 이용한 메탄의 수증기 개질 반응 (Solar Steam Reforming of Methane utilizing Solar Simulator)

  • 도한빈;한귀영
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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    • pp.186-189
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    • 2008
  • Solar simulator를 이용한 메탄의 수증기 개질은 집광된 태양에너지를 이용하기 위한 목적으로 수행되었다. 본 연구에서는 이와 같은 태양열에너지의 화학적 축열을 실시하기 위해 Solar Simulator를 이용한 메탄의 수증기 개질을 연구하였다. 태양열 모사 램프로 1.2kW급 Xenon-arc lamp를 사용하였다. 반응기는 앞면의 Quartz Window와 촉매지지층으로 구성되어 있다. 램프의 빛은 Quartz Window를 통하여 촉매층에 직접적으로 방사되고, 방사된 빛으로 촉매지지층에서 흡열반응이 일어난다.메탄의 수증기개질 반응은 고온에서 일어나기 때문에 촉매지지체를 열에 강한 SiC로 만들어진 Ceramic foam을 사용하였다. 이 촉매지지체에 촉매를 Wash-coat하여 사용하였으며, 담지된 촉매는 Ni을 활성성분으로 하는 ICI 46-6을 사용하였다. 반응기는 318 SUS 재질로 제작되었으며, 반응기 외부는 Insulation을 하여 열손실을 감소시켰다. 실험은 온도와 공간속도에 따른 Solar Steam reforming의 반응특성을 분석하였다.

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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
    • 한국세라믹학회지
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    • 제53권5호
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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.