VAPOR-PHASE CRACKING AND COKING OF 3 AUSTRALIAN SHALE OILS - KINETICS IN THE PRESENCE AND ABSENCE OF SHALE ASH

The vapour phase thermal behaviour of shale oil samples derived from the Condor, Nagoorin carbonaceous and Stuart deposits was examined. Oils vaporized in argon were passed through packed beds of sand, or the spent shale ash corresponding to the particular oil, at temperatures between 500 and 600 degree C, over a range of residence times. Results obtained over sand were attributable to thermal cracking. The oils behaved similarly; cracking was minimal at 500 degree C at a 10 s residence time but increased as conditions became harsher. Small differences arose from the different oil compositions. Coke formation was small, compared to cracked gas production. When oil vapours were passed over spent shale ash, they again behaved similarly, but their behaviour was quite different from that over sand. Coking was prevalent at all temperatures studied and resulted in major oil losses, even at 500 degree C.