Activity of alternative hydrogen sources for the hydrodesulfurization of diesel and bitumen in the presence of water using dispersed mo-based catalyst : Advances in oil field chemistry : Downhole upgrading

The decline of conventional oil reserves has resulted in the increased utilization of high sulfur heavy oil and bitumen. Canadian heavy oils typically contain 2 to 6 wt % S. Deep sulfur removal is required before conventional processing because of the threat of catalyst poisoning as well as for environmental considerations. The usage of steam in the recovery of heavy oils produces stable water-in-oil emulsions, which require several stages of physical and chemical processing to dewater and upgrade to pipeline standards. Energy, emulsion destabilizing chemicals and the supply of pure molecular hydrogen are major costs in this upgrading. Economic returns could be improved by finding alternative sources of hydrogen or by reducing the number of processing stages for upgrading heavy oil emulsions. In our laboratory, a novel single stage process has been developed to simultaneously dewater and upgrade bitumen emulsion (1). It is based on the premise of generating hydrogen from the water of the emulsion via the water gas shift reaction (WGSR) as shown in Equation 1) and then consuming it in hydroprocessing reaction as shown in Equation 2).