• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.560-567
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• 2016

In this study, we characterized steam reforming reactions and surface of $Ni/Al_2O_3$ catalysts. Ni-Mo based catalysts were prepared by loading Mo as the co-catalyst and reaction activities of the Ni-Mo based catalysts were compared with those of Ni-based catalysts. Through the $H_2$-TPR and XPS analysis it was confirmed that this characteristic efficiency. $O_2$-TPO analysis was performed to examine the deposition characteristics, bonding structures and evaporation characteristics of carbon deposited on the surface of catalysts after long run experiments were performed for steam reforming reactions. As the results, it was found that durability was improved in Ni-Mo based catalysts inhibiting formation of graphitic carbon species which reduced reaction activities of the catalysts by strongly interacting with Ni in the steam reforming reaction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.885-894
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• 2012

A numerical study of a microchannel steam methane reforming reactor has been performed to understand the characteristics of heat and mass transfer. The integration of Rh-catalyzed steam methane reforming and Pt-catalyzed methane combustion has been simulated. The reaction rates for chemical reactions have been incorporated into the simulation. This study investigated the effect of contact time, flow pattern (parallel or counter), and channel size on the reforming performance and temperature distribution. The parallel and counter flow have opposite temperature distribution, and they show a different type of reaction rate and species mole fraction. As the contact time decreases and channel size increases, mass transfer between the catalyst layer and the flow is limited, and the reforming performance is decreased.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.375-381
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• 2013

Kinetics data were obtained for steam reforming of methane and natural gas over the commercial nickel catalyst. Variables for the steam reforming were the reaction temperature and partial pressure of reactants. Parameters for the Power law rate model and the Langmuir-Hinshelwood model were obtained from the kinetic data. As a result of the reforming reaction using pure methane as a reactant, the reaction rate could be determined by the Power law rate model as well as the Langmuir-Hinshelwood model. In the case of methane in natural gas, however, the Langmuir-Hinshelwood model is much more suitable than the Power law rate model in terms of explaining methane reforming reaction. This behavior can be attributed to the competitive adsorption of methane, ethane, propane and butane in natural gas over the same catalyst sites.

• New & Renewable Energy
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• v.20 no.1
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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.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.100-108
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• 2011

The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, $CH_4$ and $CO_2$, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. This research if for the hydrogen production through the steam reforming of the biogas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The nickel catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60%:40%, 19.32L/$g{\cdot}hr$ and $700^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ concentration was 73.9% and methane conversion rate was 98.9%.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.364-377
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• 2014

The performances of a coupled reactor in which a steam reformer and a catalytic combustor were mounted simultaneously had been investigated and compared. The combustible offgas exhausted from the anode of SOFC and MCFC were utilized as heat sources for the endothermic steam methane reforming. The catalytic combustion was used in order to burn the combustible offgas. Thermal energy released by the catalytic combustion is directly transferred to the reformer surrounding the combustor. The various operational conditions such as fuel utilization rate, steam to carbon ratio, amount of catalysts, fuel cell loads were changed. And operating variables were comprehensively identified by sensitivity analysis. The fundamental results from this experimental study show the potential abilities of the coupled reactor. Therefore the results will be of help to design and manufacture the more better coupled reactor in the future.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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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.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.355-356
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• 2014

Catalytic steam reforming of tar produced from biomass gasification was conducted using several Ni-based catalysts. K and Mn were used as a promoter over $Ni/Ru/Al_2O_3$ catalyst. The pellet and monolith type catalysts were prepared and applied to lab and bench-scale biomass gasification system. The $Ni/Ru-K/Al_2O_3$ catalyst shown higher performance than $Ni/Ru-Mn/Al_2O_3$ catalyst at low temperature range.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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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.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.252-258
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• 2011

Nickel fiber mat was investigated as a potential structured catalyst for steam reforming of biogas in the temperature range of $600-700^{\circ}C$. The activity of as-received catalyst was very low owing to the smooth surface of fibers. Pretreatment of the catalyst by oxidation followed by reduction under methane partial oxidation condition significantly improved the catalytic activity, although degradation of the activity was found during the reaction due to oxidation and sintering. This deactivation was retarded by supplying additional hydrogen in the inlet gases or by coating $CeO_2$ over the catalyst surfaces.