Specific problems in the upgrading of Alberta oil sand bitumen. An overview of its characteristic composition and structure.

Abstract

A brief overview is presented on recent advances made in the chemistry of the Alberta oil sands (AOS) and their ramifications with regard to the processing and upgrading of the bitumen. AOS bitumens are likely the residue of microbiologically degraded oils which lost their hydrogenrich acyclic and lower cyclic hydrocarbon components during degradation. This, and their exposure to sulfate-reducing bacteria, would explain the gross features of their general chemical properties. The plethora of biological markers present point to a minor terrestrial contribution to the biotic source and a mild thermal history. AOS are water-wet and separate well in the hot water process, but there are exceptions. The cause of poor separability is associated with the sand and not the bitumen. Chemisorbed organic matter may render the mineral surface oil-wet, causing processing problems. Another source of processing problems is the polymer and cokeforming propensity of asphaltene and resin: clays and olefins tend to increase polymer formation.