Methanol steam reforming in a planar wash coated microreactor integrated with a micro-combustor M. Andisheh Tadbir, M.H. Akbari* Center for Fuel Cell Research, School of Mechanical Engineering, Shiraz University, Molla-Sadra Ave., Shiraz 71348-51154, Iran article info Article history: Received 12 March 2011 Received in revised form 25 April 2011 Accepted 2 May 2011 Available online 11 August 2011 Keywords: Methanol steam reforming Methanol catalytic combustion Microreactor Hydrogen production abstract A numerical simulation of methanol steam reforming in a microreactor integrated with a methanol micro-combustor is presented. Typical Cu/ZnO/Al 2 O 3 and Pt catalysts are considered for the steam reforming and combustor channels respectively. The channel widths are considered at 700 mm in the baseline case, and the reactor length is taken at 20 mm. Effects of Cu/ZnO catalyst thickness, gas hourly space velocities of both steam reforming and combustion channels, reactor geometry, separating substrate properties, as well as inlet composition of the steam reforming channel are investigated. Results indicate that increasing catalyst thickness will enhance hydrogen production by about 68% when the catalyst thickness is increased from 10 mm to 100 mm. Gas space velocity of the steam reforming channel shows an optimum value of 3000 h 1 for hydrogen yield, and the optimum value for the space velocity of the combustor channel is calculated at 24,000 h 1 . Effects of inlet steam to carbon ratio on hydrogen yield, methanol conversion, and CO generation are also examined. In addition, effects of the separating substrate thickness and material are examined. Higher methanol conversion and hydrogen yield are obtained by choosing a thinner substrate, while no significant change is seen by changing the substrate material from steel to aluminum with considerably different thermal conductivities. The produced hydrogen from an assembly of such microreactor at optimal conditions will be sufficient to operate a low-power, portable fuel cell. Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction With the rapid advancement in technology, everyday appli- cation of electronic devices such as laptops, cell phones, music players, and in general portable devices has become inevitable. Li-ion batteries are good options for providing the required energy for such devices; however, emerging small-scale fuel cells provide an appropriate substitute for these batteries [1e3]. One important issue when dealing with portable fuel cells is the method to provide the required hydrogen. One viable option is hydrogen production via thermo-chemical reforming of hydrocarbon fuels. Methanol is one of the best choices, since it is a liquid at room temperature (in contrast to methane) and is solvable in water, and hence, can be easily stored in small cartridges premixed with water. It also has a high energy density and hydrogen-to-carbon ratio [4,5]. There are different techniques for thermo-chemical production of hydrogen from hydrocarbons which are: steam reforming (SR), partial oxidation (POX), and auto- thermal reforming (ATR). Various investigations have been conducted on methanol reforming in microreactors [6e13]. Peppley et al. [14] derived a comprehensive kinetic model for methanol steam reforming over Cu/ZnO/Al 2 O 3 catalyst. Their kinetic model was developed based on an analysis of the * Corresponding author. Tel.: þ98 917 308 8424; fax: þ98 711 647 3511. E-mail addresses: mhd.andisheh@gmail.com (M.A. Tadbir), h-akbari@shirazu.ac.ir (M.H. Akbari). Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 36 (2011) 12822 e12832 0360-3199/$ e see front matter Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2011.05.010