Catalytic steam gasification of n-C5 asphaltenes by kaolin-based catalysts in a fixed-bed reactor

Abstract

A possibility of low temperature catalytic steam gasification of n-C5 asphaltenes mixed in light cyclic oil (LCO) in a fixed bed reactor is tested and presented. Four meta kaolin based catalysts containing one alkali (K or Cs), one alkaline earth (Ca or Ba) metal oxides were characterized and tested. Two of these four catalysts also contained NiO nanoparticles in addition to alkali and alkaline earth metal oxides. Addition of sugar as a porogen to kaolin created meso as well as macroporosity. These mesoporous–macroporous meta kaolin based materials are intended to work mainly as catalysts for steam gasification of the adsorbed asphaltenes. XRD data showed presence of Ni3S2 in the spent catalyst. It was found that low temperature catalytic steam gasification was possible by all four catalysts. However, replacement of Ca by Ba increased H2 production. Also, incorporation of NiO nanoparticles promoted further H2 production during the steam gasification of the adsorbed asphaltenes, leading to CO2 and H2 as major products with less side reactions. Of the two nickel-based catalysts, 3NiO6Cs6Ba seems to be the more promising material, with slightly lower activation energy, and higher production of gases per mole of metal contained in the catalyst.