Steam reforming of light oxygenates

Abstract

Steam reforming (SR) of ethanol, acetic acid, acetone, acetol, 1-propanol, and propanal has been investigated over Ni/MgAl₂O₄ at temperatures between 400 and 700 °C and at a steam-to-carbon-ratio (S/C) of 6. The yield of H₂ and conversion increased with temperature, while the yield of by-products decreased with temperature in the SR of the investigated compounds. The yield of H₂ approached the thermodynamic limit at the highest temperatures investigated. No significant differences in conversion as a function of temperature among the different model compounds were observed. However, the product distribution depended on the model compound, and C₃-oxygenates produced a larger fraction of by-products compared to C₂-oxygenates. Temperatures of 600 °C or above were generally needed to minimize the fraction of by-products and obtain a syngas containing mainly CO, CO₂, H₂, and H₂O with only traces of CH₄. Significant deactivation of the catalyst was observed for all of the compounds and was mainly due to carbon formation. The carbon formation was highest for alcohols due to a high formation of olefins, which are potent coke precursors.