Method and apparatus for the solvent extraction of oil from bitumen containing tar sand

patentA method and apparatus for extracting bitumen whereby tar sand containing bitumen components is contacted with a heated thinning oil mixture to reduce the tar sand viscosity and dissolve bitumen to form a lower viscosity feed slurry. The feed slurry is contacted with a light oil in a separator wherein the mixture is separated into product oil and oil sand. The oil sand is washed with solvent in a countercurrent fashion to extract occluded oil to form the light oil. Washed sand containing solvent is heated above the boiling point of the solvent in a multi-hearth solvent recovery furnace to vaporize the solvent. The solvent vapors are stripped from the sand by flowing inert gas through the sand in the multi-hearth solvent recovery furnace. Inert gas containing solvent vapors is directed from the multi-hearth solvent recovery furnace to a heat exchanger/scrubber where the inert gas and solvent vapors are contacted with product oil from the separator. The solvent vapors are absorbed by the product oil to form the heated thinning oil mixture which is contacted with the tar sand. The resulting thinning oil temperature is greater than the product oil due to heat transfer from the solvent vapors and inert gas. Inert gas is recycled from the heat exchanger/scrubber back to the multi-hearth solvent recovery furnace