EXTRACTION OF OIL SAND BITUMEN WITH TWO SOLVENTS

摘要

A process for extracting bitumen from oil sand using a combination of heavy solvent and light solvent is provided comprising contacting mined oil sand with a non-flammable heavy solvent (HS) to produce a dense oil sand slurry; mixing the dense slurry with a light solvent (LS) to give a heavy solvent to light solvent (HS/LS) mass ratio of about 70/30 to 50/50 and subjecting the diluted oil sand slurry to a first stage solid-liquid separation to produce a first liquids stream containing bitumen and a first solids stream; mixing the solids stream with a mixed solvent having a HS/LS mass ratio of about 75/25 to 55/45 and subjecting the diluted solids stream to a second stage solid-liquid separation to produce a second liquids stream and a second solids stream; rinsing the solids stream with a countercurrent flow of LS to recover the HS and produce spent solids; and drying the spent solids to LS concentration of less than 160 g/tonne solids.