Thermal Cracking of Athabasca Oil-Sands Oil Part 1. - Changes in Some Properties of the Oil and its Components

Abstract

Abstract Partial thermal cracking of virgin Athabasca oil-sands oil at atmosphericpressure with simultaneous removal of distillate, followed by filtration, removes all extraneous mineral matter as well as the smallamounts ofcoke produced during the thermal cracking. A study was made of the filtratesand of fractions from the filtrates in order to gain an insight into some ofthe complex changes which occur in the oil during thermal cracking. The changes which occur in molecular weight, ultimate composition, B.t.u.value, specific gravity and penetration during thermal cracking of the Athabasca oil are illustrated. In addition, it is shown that portions of theasphaltene material (designated as varsol- or kerosene-insolubles) from somefiltrates have interesting characteristics. For example, on heating at 1,022°F, these insolubles form honeycomb-like structures which represent volumeexpansions as great as 200 to 300 times. Some of these structures may be cutwith a knife without crumbling. Also, the formation of these honeycombs is, under certain conditions, sensitive to prior oxidation of the insolubles atelevated temperatures and to other factors. Furthermore, on mixing theinsolubles with dry Drumheller subbituminous B coal (a non-caking coal) in theratio of only 1 part of insolubles to 11 parts of coal, and carbonizing rapidlyat 1,022°F, a fairly hard lump is obtained which is similar in hardness to thatproduced by similarly carbonizing an unconsolidated mixture of the dry Drumheller coal and dry Crowsnest Pass caking coal in a ratio of 1:1. Introduction The dehydration of Virgin oil recovered from the Athabasca oil sands byeither the hot-water-washing processor the cold-water-washing processreveals the presence of relatively large amounts of clay, silt and very finesand, the actual amounts depending on the particular experimental conditions. Consequently, interest heretofore has centred on the yields and quality of thedistillates produced from the oil.