Heavy Oils, Shale, and Tar Sand

The quality of petroleum varies and, according to specific gravity and viscosity, we talk about light, medium, heavy, and extraheavy crude oils. Light oils of low 

Processing heavy oils and bitumens represent challenges for presently used refinery processes, as heavy oils and bitumens can poison the metal catalysts used in the current refineries. The use of superacid catalysts, which are less sensitive to these feeds, is one possible solution715 to this problem. 

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