Cu–Zn–Al based catalysts for low temperature bioethanol steam reforming by solar energy

Bioethanol steam reforming is one of the most promising route to produce hydrogen from a renewable liquid biofuel. Activity of two Cu–Zn–Al based catalysts was investigated at low temperatures, ranging from 420 to 500 °C, in view of temperature limitations associated with solar energy supply by parabolic trough technology. At 450 °C the space velocity effect was also investigated, by varying the weight hourly space velocity (WHSV) from 1.67 to 3.32 h⁻¹. In each experimental conditions, together with the expected hydrogen and carbon dioxide, also methane, ethylene, acetaldehyde and diethylether were detect as products, so indicating the presence of several parallel reaction pathways. A good selectivity to ethanol reforming was obtained only at 500 °C (with values of the H₂/CO₂ mol ratio of 3.4 and 4.5) with both catalysts, while at lower temperatures alcohol dehydration into acetaldehyde seemed to be the main reaction.