Upgrading oil sand bitumen under superheated steam over ceria-based nanocomposite catalysts

Abstract

Upgrading of oil sand bitumen by catalytic cracking of its heavy oil fraction via ceria-based catalysts was investigated in a fixed-bed flow-type reactor, in the presence of superheated steam and addition of water. The reaction was carried out over CeZr, FeCoCeZr1 and FeCoCeZr2 catalysts at 470 °C, Wcat/FFeed of 0.4 h and FH2O/Ffeed = 2. The oxygen species in the crystal lattice of the catalysts and the surface Lewis acid sites are responsible for the oxidative decomposition and catalytic cracking of the heavy oil, respectively. Higher light oil yield of approximately 60 mol%-C (gas oil and vacuum gas oil) and lowest coke yield (20.45 mol%-C) was obtained over CeZr catalyst. FeCoCeZr1 and FeCoCeZr2 gave lower residue and higher gas yield, with higher H2 and lower CO2 composition when compared to CeZr. The spent catalysts showed structural stability which is supported by the X-ray diffraction analysis, and thermal stability which agrees to the minimal weight loss from thermogravimetric analysis. The catalysts also exhibited good potential for reusability based on the analysis of the spent samples.