Reaction mechanism of steam re-forming

Abstract

The reaction of steam with propane and butane over nickel catalysts has been investigated at 600° and atmospheric pressure. Experiments in a flow-type apparatus, providing a range of very short contact times, allowed short-lived intermediates to be detected and demonstrated the occurrence of the following sequence of steps: (i) catalytic cracking and hydrogenation of paraffins leading mainly to low olefins, methane, and some hydrogen; (ii) reaction of the primary intermediates (olefins, methane) with steam yielding initially hydrogen and carbon dioxide; (iii) the slower establishment of equilibrium among the products. This scheme provides a broad explanation of the behaviour of the steam-re-forming process.