Steam reforming of glycerol: Hydrogen production optimization

Abstract

The glycerol steam reforming reaction was studied using Pt-based catalysts in order to selectively produce hydrogen. The global steam reforming reaction is the combination of two consecutive steps: i) glycerol decomposition and ii) water gas shift reaction (WGS). Pt supported over solids with markedly different physicochemical properties (SiO2, MgO, Al2O3 and TiO2) were prepared and tested in steam reforming reaction of glycerol (10% wt. aqueous solution) at 573e623 K. Glycerol to gas products conversion of 100% and hydrogen yield of 78.8% were obtained by using Pt over an inert support (Pt/SiO2 prepared from chlorine-free solution). Acidic supports favored undesirable reactions conducting to liquid products and coke precursors. Furthermore, WGS reaction was studied at reaction conditions compatible with steam reforming over Pt/SiO2, Pt/TiO2 and two catalysts prepared for that purpose: Pt/CeO2 and Pt/ZrO2. Pt/TiO2 showed the highest CO conversion at 623 K. In order to maximize H2 formation, a double-bed catalytic system (0.5% wt. Pt/SiO2 þ 0.5% wt. Pt/TiO2) was used achieving a 100% hydrogen yield without deactivation on stream.