Ethanol steam reforming over Rh Rh-Pd/CeO2: Theoretical and experimental study of a catalytic membrane reactor

M. ESPERANZA ADROVER; N.J. DIVINS; MARISA N. PEDERNERA; J. LLORCA; EDUARDO LOPEZ

Porto

Congreso; 11th International Conference on Catalysis in Membrane Reactors; 2013

University of Porto

Hydrogen production has become an important topic over the past decades, but nowadays it is of greater interest because of fuel cell technology developments. This situation has intensified the research tending both to improve the existing technologies and to develop new processes to generate and purify H2. Reforming or partial oxidation of hydrocarbons or alcohols have been reported as the main processes to obtain the required hydrogen. Bioethanol is a promising raw material due to its low toxicity, high energetic density and it can be produced from renewable raw materials. As a consequence, the main purpose of this abstract is to study the bioethanol steam reforming reaction. As appropriate candidates for this reaction in terms of activity and selectivity, inexpensive catalysts based on Ni or Co have been proposed [1,2]. However, these catalysts are reported to suffer from severe deactivation during ESR due to extensive carbon deposition [3]. Noble metal-based catalysts (Pd, Pt, Rh, Ru) perform well for ESR resulting Rh generally to bemore effective than other noble metals [4]. They are stable and exhibit high activity, provided that high enough temperature levels are selected for operation (T > 600 °C). Supports commonly used include MgO, La2O3 and CeO2; Al2O3 was pointed as disadvantageous as promotes the formation of ethylene, which is a source of coke formation [5]. Regarding cerium oxide supports, the size of the ceria crystallites plays a determinant role; small crystals promote an upgraded interaction with the noble metal increasing the catalytic properties [6]. However, the hydrogen produced has to be purified before feeding it to a PEM fuel cell. An interesting alternative is to use Pd/Ag membranes in order to separate pure hydrogen from the reaction products. The aimed of this abstract is to describe the kinetic bihavior of the bioethanol steam reforming as aforementioned catalysed by Pd?Rh/CeO2 and to obtain pure hydrogen by means of a commercial Pd/Ag membrane placed downstream whose parameters has been determined.