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Abstract: Microreactors have important advantages due to the increased heat and mass transfer resulting from the small dimensions of the system. This results in enhanced performance and efficiency. Microreformers with wall-coated or suspended catalytic layer configurations have been studied due to their lower transport resistances compared to packed-bed microreformers. In the present work, a theoretical study of the reacting flow in a wall-coated microreformer is carried out. The theoretical results for the conversions and carbon monoxide concentration of wall-coated reformers are compared with the reported experimental data. The effects of important parameters for wall-coated reformers such as the catalyst layer thickness, wall temperature, and the flow velocity of the reactants are studied. Recommendations for the design of micro wall-coated reformers are provided. [Copyright &y& Elsevier]

Abstract: In the present study a small steam–methanol reformer with a colloid nanocatalyst is utilized to produce hydrogen. Radiation from a focused continuous green light laser (514nm wavelength) is used to provide the energy for steam–methanol reforming. Nanocatalyst particles, fabricated by using pulsed laser ablation technology, result in a highly active catalyst with high surface to volume ratio. A small novel reformer fabricated with a borosilicate capillary is employed to increase the local temperature of the reformer and thereby increase hydrogen production. The hydrogen production output efficiency is determined and a value of 5% is achieved. Experiments using concentrated solar simulator light as the radiation source are also carried out. The results show that hydrogen production by solar steam–methanol colloid nanocatalyst reforming is both feasible and promising. [Copyright &y& Elsevier]

Abstract: An experimental and analytical study of nanocatalyst fabrication and the production of hydrogen utilizing photon energy was carried out. The porous structure of the nanocatalyst provides a high surface to volume ratio of the catalytic layer thereby increasing the activity of the catalyst. An experiment was carried out to obtain an effective nanocatalyst by using pulsed laser ablation (PLA) technology. The properties of the nanocatalyst are directly related to the performance of the catalytic reaction and are analyzed. Experiments and analyses were carried out to evaluate the activity enhancement of the nanocatalyst. Photonic energy provides the heat for the endothermic steam–methanol reforming reaction producing hydrogen. It is shown that photonic induced steam–methanol reforming in a nanocatalyst reformer is feasible and promising. [Copyright &y& Elsevier]

Abstract: An experimental and theoretical study of steam reforming of methanol is carried out in a packed-bed microreactor with internal heating. Experimental results of the methanol conversion and carbon monoxide concentration in an internally heated reformer are compared with those of an externally heated reformer. Higher methanol conversion and carbon monoxide concentration are obtained for internal heating at the same conditions. The results show the conversion efficiency of methanol and CO concentration increase with increasing internal heating rate over the range of operating conditions. A correlation for the conversion efficiency of methanol has been obtained as a function of the internal heating rate and a dimensionless time parameter which represents the ratio of the characteristic time of the methanol flow to the time for chemical reaction. [Copyright &y& Elsevier]

Abstract: Steam reforming of methanol is investigated numerically considering both heat and mass transfer of the species in a packed bed microreactor. The numerical results are shown to be in good agreement with experimental data [M.T. Lee, R. Greif, C.P. Grigoropoulos, H.G. Park, F.K. Hsu, J. Power Sources Transport in, 166 (2007) 194–201] with a BASF F3-01(CuO/ZnO/Al2O3) catalyst. A correlation for the conversion efficiency of methanol has been obtained as a function of the operating temperature and a dimensionless time parameter which represents the ratio of the characteristic time of the methanol flow to the time for chemical reaction. The results show that for the constant wall temperature condition the steam reforming process of methanol results in a nearly uniform temperature throughout the microreactor over the range of operating conditions. [Copyright &y& Elsevier]

Abstract: In the present study, a hydrogen polymer electrolyte fuel cell (PEFC) micropowerplant in combination with a steam reformer fed by methanol and a direct methanol fuel cell (DMFC) micropowerplant are analyzed numerically regarding their exergetic efficiency. The effects of concentration and activation overpotentials, and ohmic resistance on the efficiency are considered in quasi-two-dimensional fuel cell models. The influence of significant operational parameters on the exergetic efficiency is examined numerically. Experimental results are conducted for the steam reformer. This work shows the importance of an exergy analysis of the fuel cell as part of an entire thermodynamic system generating electric power and compares PEFC and DMFC micropowerplants exergetically. [Copyright &y& Elsevier]

We have fabricated CuO/ZnO nanowire (NW) catalyst for hydrogen production by solar thermal steam-methanol reforming (SMR). Such NW catalyst is expected to be more durable than the conventional nanoparticle catalysts by avoiding agglomeration. ZnO NWs are synthesized by hydrothermal growth on quartz and glass substrates. The ZnO NWs are then coated with CuO by thermal decomposition of copper nitrate using UV pulsed laser as a heat source for prototyping. A solar simulator is used as a heat source for the demonstration of the SMR in water/methanol mixture solution. Gas chromatograph (GC) exhibits increasing mole fraction of produced hydrogen with irradiated time. We then fabricate the catalyst on a large area glass plate substrate by the CuO deposition using an electric heater to confirm the SMR and demonstrate scaling-up. The SMR is briefly demonstrated by feeding water vapor/methanol mixture gas to the catalyst heated by an electric heater, giving thermally produced hydrogen (CO/H 2 = 0.019) in the product gas detected by GC. [ABSTRACT FROM AUTHOR]