Ethanol steam reforming kinetics of a Pd–Ag membrane reactor Silvano Tosti a, *, Angelo Basile b , Rodolfo Borelli a , Fabio Borgognoni a , Stefano Castelli c , Massimiliano Fabbricino d , Fausto Gallucci e , Celeste Licusati d a ENEA, Dipartimento FPN, C.R. ENEA Frascati, Via E. Fermi 45, Frascati, (RM) I-00044, Italy b Institute on Membrane Technology, ITM-CNR, c/o Univ. of Calabria, via P. Bucci, Cubo 17/C, 87030 Rende (CS), Italy c ENEA, Dipartimento ACS, C.R. ENEA Casaccia, Via Anguillarese 301, Roma I-00123, Italy d Dept. of Hydraulic and Environmental Engineering, Univ. of Naples Federico II, Via Claudio 21, Naples 80125, Italy e Fundamentals of Chemical Reaction Engineering Group, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands article info Article history: Received 30 January 2009 Received in revised form 13 March 2009 Accepted 17 March 2009 Available online 25 April 2009 Keywords: Pd membrane reactors Ethanol steam reforming Reaction kinetics abstract The ethanol steam reforming reaction carried out in a Pd-based tubular membrane reactor has been modelled via a finite element code. The model considers the membrane tube divided into finite volume elements where the mass balances for both lumen and shell sides are carried out accordingly to the reaction and permeation kinetics. Especially, a simplified ‘‘power law’’ has been applied for the reaction kinetics: the comparison with experimental data obtained by using three different kinds of catalyst (Ru, Pt and Ni based) permitted defining the coefficients of the kinetics expression as well as to validate the model. Based on the Damkohler–Peclet analysis, the optimization of the membrane reformer has been also approached. ª 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. 1. Introduction The production of hydrogen via sustainable processes is being considered a strategy for reducing the greenhouse-gas emis- sions responsible for the global warming [1]. However, beside the technological problems related to a wide diffusion of hydrogen-based energy systems (i.e., hydrogen storage, transportation and safe use), the hydrogen production processes need a complete revision. Presently, hydrogen is mainly produced from fossil sources such as methane and coke [2], then strongly reducing the benefits from the envi- ronmental protection point of view. Duly, among the processes regarded as ‘‘clean’’ for the production of hydrogen, the reforming of ethanol/water mixtures obtained from fermentation of biomasses is taken into consideration [3–7]. In particular, recent studies have demonstrated that the production of bio-ethanol from cellulose [8] instead of other biomasses such as corn and sugarcane can be considered effective for reducing the greenhouse-gas emissions as well as socially acceptable (i.e., without driving up the food prices) [9]. The ethanol steam reforming is an endothermic catalysed reaction: C 2 H 5 OH þ H 2 O 5 2CO þ 4H 2 DH 298K ¼ 239.5 kJ mol 1 (1) The CO is converted into CO 2 via the water gas shift reaction: CO þ H 2 O 5 CO 2 þ H 2 DH 298K ¼41.2 kJ mol 1 (2) * Corresponding author. E-mail address: silvano.tosti@enea.it (S. Tosti). Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he 0360-3199/$ – see front matter ª 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2009.03.049 international journal of hydrogen energy 34 (2009) 4747–4754