Autoxidation for Pre-refining of Oil Sands

Oxidative desulfurization of oil sands bitumen as pre-refining methodology to improve bitumen quality in the absence of catalysts was studied. It has potential advantages such as employing a cheap reagent (air) and moderate processing conditions (<180 °C, autogenous pressure). The specific aims of our research were: (a) To establish whether autoxidation followed by aqueous extraction is able to efficiently desulfurize bitumen; (b) To establish whether autoxidation conducted in the presence of a diluent is necessary to limit bitumen hardening as a result of free radical addition reactions; (c) To establish whether autoxidation is selective enough toward organosulfur compounds, because it is undesirable to cause extensive hydrocarbon oxidation; and (d) To establish whether autoxidation reactions are more efficient < 150 °C or in the temperature range 150-180 °C, which reportedly results in selective autoxidation. These questions were addressed and best sulphur removal obtained was 46-47 %.