Cold dense slurrying process for extracting bitumen from oil sand

摘要

Average grade oil sand is mixed with water to produce a low temperature (20-35° C.), dense (1.4-1.65 g/cc) slurry. The slurry is pumped through a pipeline for sufficient time to condition it. Air is injected into the slurry after the last pump. The slurry density is adjusted to about 1.5 g/cc by adding flood water near the end of the pipeline. The slurry is introduced into a primary separation vessel slurry as it is introduced into the (PSV), excess air is vented from the PSV and a hot water underwash is used to heat the froth produced. Slurry loading to the PSV is greater than about 4.78 tonnes of oil sand/hour/square meter to reduce velocity gradient in the fluid in the vessel. Bitumen froth is recovered. When fed low grade oil sand, the process is modified by adding flotation aid chemicals to the slurry in the pipeline and subjecting the PSV tailings and middlings to secondary recovery with agitation and aeration in a secondary separation vessel.