• 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.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.503-506
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• 2008

Liquid hydrocarbon fuels, such as gasoline, kerosene, diesel and JP 8, can be good candidates for SOFC (solid oxide fuel cell) system fuel due to their high hydrogen density. Autothermal reforming (ATR) is suitable for liquid hydrocarbon fuel reforming because oxygen can decompose the aromatics in liquid fuel and steam can suppress the carbon deposition during catalytic reaction. The advantage of ATR is that it has a simple system construction due to exothermicity of ATR reaction. We control the exothermicity of reaction, make the reaction possible design a self-sustaining ATR reactor. A self-sustained 1kW-class kerosene autothermal reformer is introduced in this paper. The 1kW-class kerosene reformer was continuously operated for about 140 hours without degradation of reforming performance.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1323-1327
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• 2001

The catalyst Ni/MgO (Ni : 15 wt%) has been applied to methane reforming reactions, such as steam reforming of methane (SRM), partial oxidation of methane (POM), and oxy-steam reforming of methane (OSRM). It showed high activity and good stability in all the reforming reactions. Especially, it exhibited stable catalytic performance even in stoichiometric SRM (H2O/CH4 = 1). From TPR and H2 pulse chemisorption results, a strong interaction between NiO and MgO results in a high dispersion of Ni crystallite. Pulse reaction results revealed that both CH4 and O2 are activated on the surface of metallic Ni over the catalyst, and then surface carbon species react with adsorbed oxygen to produce CO.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.232-238
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• 2021

The development of a low cost catalyst with high performance and small amount of carbon deposition on catalyst from toluene steam reforming were investigated by using coal ash as a support material. Ni-loaded coal ash catalyst showed similar catalytic activity for toluene steam reforming compared with the Ni/Al2O3. At 800 ℃, the toluene conversion was 77% for Ni/TAL, 68% for Ni/KPU and 78% for Ni/Al2O3. Ni/TAL showed similar toluene conversion to Ni/Al2O3. However, Ni/KPU produced higher hydrogen yield at relatively lower toluene conversion. Ni/KPU catalyst showed a remarkable ability of suppressing the carbon deposition. The difference in coke deposition and hydrogen yield is due to the composition of KPU ash (Ca and Fe) which increase coke resistance and water gas shift reaction. This study suggests that coal ash catalysts have great potential for the application in the steam reforming of biomass tar.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.2
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• pp.119-126
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• 2002

The methanol partial oxidation using commercial $CuO/ZnO/Al_2O_3$ catalysts in a plug flow reactor was studied in the temperature range of $200{\sim}250^{\circ}C$ at atmospheric pressure, It was achieved the high activities by Cu-based catalysts and the selectivity of $CO_2$/$H_2$ was 100% when $O_2$ was fully convened. The reactivity changes and their hysteresis with increasing/decreasing temperatures were observed due to the chemical state differences between the oxidation and the reduction on the Cu surface, It was suggested as the two-step reaction: the complete oxidation and the following steam reforming for methanol, which was indicated by the distributions of final products vs. the residence time. In addition, the complete oxidation step was shown to be extremely fast and the total reaction rate can be controlled by the steam reforming reaction.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.720-722
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• 2009

This work is mainly focused at developing the hydrogen production unit with the capacity of 20 $Nm^3/h$ of high purity hydrogen. At present steam reforming of natural gas is the preferable method to produce hydrogen at the point of production cost. The developed hydrogen production unit composed of natural gas reformer and pressure swing adsorption system. To improve the thermal efficiency of steam reforming reactor, the internal heat recuperating structure was adopted. The heat contained in reformed gas which comes out of the catalytic beds recovered by reaction feed stream. These features of design reduce the fuel consumption into burner and the heat duty of external heat exchangers, such as feed pre-heater and steam generator. The production rate of natural gas reformer was 41.7 $Nm^3/h$ as a dryreformate basis. The composition of PSA feed gas was $H_2$ 78.26%, $CO_2$ 18.49%, CO 1.43% and $CH_4$ 1.85%. The integrated production unit can produce 21.1 $Nm^3/h$ of high-purity hydrogen (99.997%). The hydrogen production efficiency of the developed unit was more than 58% as an LHV basis.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.75-81
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• 2007

Steam reforming of methane using Xe-arc solar simulator was studied for the application of concentrated solar energy into chemical reaction. The reactor, a volumetric absorber, consisted of a porous ceramic foam disk coated with commercial reforming catalyst. Operating temperature was in the range of $450\;-\;550^{\circ}C$ and the excess steam ratio to methane was from 3.0 to 5.0. At the steady-state condition, the conversion of methane Increased with temperature in the range of 15 % - 30 % and the experimentally determined conversion was found to be close to theoretical equilibrium conversion. It was also found that the CO selectivity slightly decreased with excess steam ratio. Finally, the conversion of methane decreased significantly with space velocity of reactants.

• New & Renewable Energy
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• v.19 no.2
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• pp.1-12
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• 2023

In this study, an efficient one-dimensional model was developed for predicting microchannel steam/methane reformers with thin washcoat catalyst layers with a focus on low-pressure reforming conditions suitable for distributed hydrogen production systems for fuel cell applications. The governing equations for steam/methane mixture gas flowing through the microchannel reformer were derived considering the species conservation with reforming reactions and energy conservation with external convective heat supply. The reaction rates for the developed model were simply determined through the catalyst effectiveness factor correlations instead of performing complicated calculations for the steam/methane reforming process occurring inside the washcoat catalyst layers. The accuracy of the developed was verified by comparing the results obtained herein with those obtained by the detailed computational fluid dynamics calculation for the same microchannel reformer.

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.78-84
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• 2013

A numerical study on the heat and fluid flow has carried out for the design of the steam reforming reactor which consists of six reforming tubes and one burner. Reforming reaction calculation is coupled with the heat and fluid flow one. The burner type in the reforming reactor is chosen through the fluid flow calculation according to different type of burner structure. It is shown that the significant temperature gradient exists in the reforming reactor, affecting the component variation along the length of reforming tube. The component ratio of reforming gas is changed by the variation of SCR and GHSV.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.1996-2000
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• 2008

In autothermal reforming reaction, oxygen to carbon ratio (OCR) and steam to carbon ratio (SCR) are significant factors, which control temperature and carbon deposition into the reactor. The OCR is more sensitive than the SCR to affect the temperature distribution and reforming efficiency. In conventional operation, hydrocarbon fuel, steam, and oxygen was homogeneously mixed and injected into the reactor in order to get hydrogen-rich gas. The temperature was abruptly raised due to fast oxidation reaction in the former part of the reactor. Deactivation of packed catalysts can be accelerated there. In the present study, therefore, the effect of the oxygen distribution is introduced and investigated to suppress the carbon deposition and to maintain the reactor in the mild operating temperature (e.g., $700{\sim}800^{\circ}C$). In order to investigate the effect numerically, the following models are adopted; heterogeneous reaction model and two-medium model for heat balance.