Steam Reforming of Alcohols for Hydrogen Production

To understand the complexity of the reactions involved in the steam reforming of glycerol and with the aim of identifying the contribution of C-C and C-O bonds cleavage, in this work we have studied the steam reforming of C3 alcohols simpler than glycerol such as 1-propanol, 2-propanol, 1,2-propanediol and 1,3-propanediol. A Pt/SiO2 catalyst was employed and were studied the conversion and the product distribution for each alcohol. It was possible to determine the absence of C-O and C-C bonds cleavage in a secondary alcohol such as 2-propanol and 1,2 propanediol. The presence of reaction intermediates with an aldehyde function, deactivates the catalyst due to their strong adsorption on the metal site, moreover, the presence of hydroxyl-aldehydes promotes the C-C bonds cleavage favoring the gas production. The reaction pathway from glycerol to acetol by cleavage C-O bonding or dehydration on metal site is responsible for the subsequent reactions leading to deactivation. The main reaction pathway to obtain gaseous products from glycerol reforming involve C-C bonds cleavage of primary alcohols such as 2,3-dihydroxypropanal, 1,2-ethanediol and 2-hydroxyethanal. In order to confirm the proposed reaction pathways, steam reforming of ethylene glycol was performed, identifying this compound as primary intermediates to obtain gaseous products from glycerol.