HYDROCRACKING OF HEAVY OILS IN PRESENCE OF DRY MIXED ADDITIVE

: An improved process is described for the hydrocracking of heavy hydrocarbon oil, such as oils extracted from tar sands. The charge oil in the presence of an excess of hydrogen is passed through a tubular hydrocracking zone, and the effluent emerging from the top of the zone is separated into a gaseous stream containing a wide boiling range material and a liquid stream containing heavy hydrocarbons. According to the novel feature, the hydrocracking process is carried out in the presence of an additive consisting of finely divided coal or other carbonaceous material dry mixed with catalytically active metals such as iron, cobalt and molybdenum. The additive is slurried with the charge stock and has been found to greatly reduce coke precursors and thereby prevent the formation of carbonaceous deposits in the reaction zone while also being effective in reducing the sulphur concentration of the product.