COLD DENSE SLURRYING PROCESS FOR EXTRACTING BITUMEN FROM OIL SAND

摘要

Average grade oil sand is mixed with water to produce a lowtemperature (preferably 20 - 35°C), dense (1.4 -1.65 g/cc) slurry. Theslurryis pumped through a pipeline for sufficient time to condition it. Air isinjectedinto the slurry after the last pump. The slurry density is adjusted to about1.5g/cc by adding flood water near the end of the pipeline. The slurry isintroduced into a primary separation vessel (PSV), excess air is vented fromthe slurry as it is introduced into the PSV and a hot water underwash is usedto heat the froth produced. Slurry loading to the PSV is greater than about4.78 tonnes of oil sand/hour/square meter to reduce velocity gradient in thefluid 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 thepipeline and subjecting the PSV tailings and middlings to secondary recoverywith agitation and aeration in a secondary separation vessel.