STUDY OF COMPOSITION OF NIGERIAN TAR SAND BITUMEN

Abstract

Compositional characterization techniques developed for high-boiling heavy ends of petroleum have been applied to Nigerian tar sand bitumen. The bitumen was subjected to ion-exchange and ferric chloride coordination chromatography to separate acids, bases and neutral nitrogen compounds. The remaining Hydrocarbon plus fraction was separated into saturates, monoarmatics, diaromatics and polyaromatic plus polar compounds on dual packed column of silica - alumina gels. Simulated distillation data were also obtained for the bitumen and were used to plot a boiling point distribution curve. Results of the characterization are compared with results in literature for tar sand bitumens and petroleum. Comparison of the results with the Utah and the Athabasca bitumens provides a basis for the evaluation of the Nigerian bitumen because considerable information about the processing characteristics of the Athabasca bitumen have been reported by many researchers. Simulated distillation and chromatographic separation data indicate that the bitumen used in this present study closely resembles the Athabasca and the Utah tar sand bitumens with respect to hydrocarbon/non-hydrocarbon distribution, and the high-boiling petroleum fraction with respect to non-distilling portion. Information about the composition of bitumens and heavy oils is needed because of the prospect of using heavy oils including bitumens as energy sources.