Catalytic cracking of heavy oil with iron oxide-based catalysts using hydrogen and oxygen species from steam

Abstract

This study investigated the transfer of oxygen and hydrogen species from steam to product during the catalytic cracking of heavy oil with iron oxide-based catalysts containing zirconia and alumina. Light oil and carbon dioxide were produced in the catalytic oxidative cracking of petroleum residual oil in the presence of steam. The alkene/alkane ratio of light aliphatic hydrocarbons decreased and carbon dioxide yield increased with higher flow rate ratio of steam to feedstock. The steam catalytic cracking of dodecylbenzene as a model compound of heavy oil showed lower alkene/alkane ratio and generation of a small amount of oxygen-containing compounds. The oxygen species derived from steam reacted with heavy oil and were transferred to carbon dioxide and a small amount of oxygen-containing compounds, producing hydrogen species from the steam. The hydrogen species were transferred to light hydrocarbons, thus suppressing alkene generation. The alkene/alkane ratio decreased with higher supporting zirconia content in the catalyst because zirconia promotes hydrogen generation from steam.