An integrated catalytic approach for the production of hydrogen by glycerol reforming coupled with water-gas shift Edward L. Kunkes a , Ricardo R. Soares a,b , Dante A. Simonetti a , James A. Dumesic a, * a Department of Chemical and Biological Engineering, University of Wisconsin, 1415 Engineering Drive, Madison, WI 53706, USA b Faculdade de Engenharia Quı´mica, Universidade Federal de Uberlaˆndia, Av. Joa˜o Naves de A ´ vila 2121, Uberla ˆndia, MG 38408-100, Brazil 1. Introduction Researchers are currently developing ways to utilize renewable resources as feedstocks for energy generation and chemical production, with the aim of reducing CO 2 emissions as well as the dependency on fossil fuels. Among these efforts, hydrogen production has been attracting considerable attention. For example, hydrogen can be used as an environmentally friendly fuel and as a feedstock for ammonia-based fertilizers or other chemicals. Hydrogen is also gaining widespread applications with the advent of fuel cell technologies [1]. Additionally, many catalytic bio-fuels production processes, including several devel- oped by our group, require a feed stream of renewable hydrogen [2–4]. In this work, we report a two-stage, single reactor process for the production of hydrogen from glycerol. Glycerol is currently produced as a by-product of the trans-esterification of fats and oils in biodiesel production [5]. Glycerol can also be produced by the fermentation of sugars [6] or catalytic hydrogenolysis of sugars and sugar-alcohols [7]. Hydrogen-rich gas mixtures can be obtained from biomass feedstocks by a two-step process. In the first step, the oxygenated organic compound generates a mixture of CO and H 2 (denoted as bio-syn-gas) according to the following Eq. (1): C n H m O k þðn  kÞH 2 O ! nCO þðn þ m=2  kÞH 2 (1) In the second step, carbon monoxide undergoes water-gas shift (WGS) with steam leading to CO 2 and the formation of additional hydrogen: nCO þ nH 2 O $ nCO 2 þ nH 2 (2) Bio-syn-gas can be produced by the gasification of carbohy- drates (n = k) at high temperatures (800–1000 K) [8–10]. More- over, several investigators report carrying out the overall hydrogen production process at temperatures above 873 K using glycerol as the raw material in steam reforming [11,12] or auto-thermal processes [13]. The WGS step is mildly exothermic (40 kJ mol 1 ), and therefore the equilibrium conversion of CO decreases at higher temperatures. Our approach to hydrogen production outlined in this paper places emphasis on the flexibility of combining glycerol reforming with downstream WGS in one reactor system to furnish CO:H 2 mixtures with variable compositions. This flexibility allows the implementation of renewable feeds in applications that require relatively pure H 2 as well as applications requiring various grades of synthesis gas (H 2 :CO = 2), such as Fischer–Tropsch synthesis and methanol synthesis [14,15]. The desired H 2 :CO ratio can be achieved by changing the concentration of the carbohydrate feed (allowing water to become the limiting reagent in WGS) or Applied Catalysis B: Environmental 90 (2009) 693–698 ARTICLE INFO Article history: Received 11 March 2009 Received in revised form 27 April 2009 Accepted 30 April 2009 Available online 9 May 2009 Keywords: Water-gas shift Reforming Hydrogen Glycerol ABSTRACT Reaction kinetics measurements of glycerol conversion on carbon-supported Pt-based bimetallic catalysts at temperatures from 548 to 623 K show that the addition of Ru, Re and Os to platinum significantly increases the catalyst activity for the production of synthesis gas (H 2 /CO mixtures) at low temperatures (548–573 K). Based on this finding, we demonstrate a gas phase catalytic process for glycerol reforming, based on the use of two catalyst beds that can be tuned to yield hydrogen (and CO 2 ) or synthesis gas at 573 K and a pressure of 1 atm. The first bed consists of a carbon-supported bimetallic platinum-based catalyst to achieve conversion of glycerol to a H 2 /CO gas mixture, followed by a second bed comprised of a catalyst that is effective for water-gas shift, such as 1.0% Pt/CeO 2 /ZrO 2 . This integrated catalytic system displayed 100% carbon conversion of concentrated glycerol solutions (30–80 wt.%) into CO 2 and CO, with a hydrogen yield equal to 80% of the amount that would ideally be obtained from the stoichiometric conversion of glycerol to H 2 and CO followed by equilibrated water-gas shift with the water present in the feed. ß 2009 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +1 6082621095; fax: +1 6082625434. E-mail address: dumesic@engr.wisc.edu (J.A. Dumesic). Contents lists available at ScienceDirect Applied Catalysis B: Environmental journal homepage: www.elsevier.com/locate/apcatb 0926-3373/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.apcatb.2009.04.032