Method of Separating Oil from Bituminous Sands and Like Oil Bearing Material (Patent No: 593381)

Inventor: Coulson, Gordon Raymond

Location: Calgary

Comments: N/A

Description: 1. The method of separating crude oil from bituminous sands which comprises diluting the oil phase through the addition of a diluent of lesser specific gravity than that of the oil in an amount sufficient to substantially reduce the specific gravity of said oil and to promote recovery of the oil, but in quantity insufficient to tend to emulsify the aqueous and oil phases under processing conditions, introducing an aqueous medium in the proportion of about two volumes per volume of oil, sand and diluent being processed to form a slurry, and applying sufficient centrifugal force to the slurry to effect a separation by densities of sand, an aqueous phase, and an oil phase substantially free from solids.
2. The method of separating crude oil from an oil-bearing sand which comprises forming a slurry of said sand, a hydrocarbon diluent of lesser specific gravity than that of the oil constituent of the sand, said diluent being in sufficient amount to reduce the specific gravity of said oil substantially below 1.0 and an aqueous medium; applying centrifugal force to the slurry to effect a separation by densities of a sand phase, an aqueous phase, and a diluted oil phase, said aqueous medium being present in the slurry in an amount sufficient to saturate the sand plus an excess sufficient to provide an aqueous barrier between the sand phase and the oil phase under the conditions employed in said centrifugal separation.
3. The method of claim 2 wherein sufficient aqueous medium is added to saturate the, sand, plus an excess sufficient to provide an aqueous barrier of approximately
80,500
Rw2
inches where R is the radius to the periphery of the centrifuge bowl and W is the rate of rotation of the centrifuge bowl in radians per second.4, The method of claim 2 wherein said aqueous medium comprises an aqueous solution of a neutral salt soluble in water which has the effect of increasing the specific gravity of the water.

5. The method of claim 2 wherein said aqueous medium comprises an aqueous solution of a salt soluble in water which has the effect of increasing the specific gravity of the water and which acts as an electrolyte.

6. The method of claim 2 wherein said aqueous medium comprises a substantially saturated aqueous solution of a salt soluble in water which has the effect of increasing the specific gravity of the water.

7. The method of claim 2 wherein said aqueous medium comprises an aqueous solution of sodium chloride.

8. The method of claim 2 wherein said aqueous medium contains sufficient of a surface active agent to reduce the surface tension of the aqueous phase below that of the oil phase but insufficient to form undesirable emulsions.

9. The method of claim 2 wherein sufficient solvent is added to reduce the specific gravity of the said oil constituent to between about 0.79 and about 0.95.

10. The method of claim 2 wherein sufficient aqueous medium is added to provide an aqueous barrier of at least one inch in depth under processing conditions.

11. The method of claim 2 wherein said solvent is added in sufficient quantity to reduce the specific gravity of said oil constituent to from about 0.79 to about 0.95, and the amount of the aqueous phase in the slurry amounts to at least 1.7 volumes per volume of diluted oil sand.

12. A continuous process for separating crude oil from an oil-bearing sand which comprises subjecting a slurry of said sand, a solvent comprising hydrocarbons of lesser specific gravity than that of the oil in said sand, and water, to a first separation including subjecting the mixture to a relatively low centrifugal force, to separate the major portion of the coarser sand from the slurry, and then subjecting the slurry thus partially freed of sand to a substantially greater centrifugal force to separate the remaining solids, and water, from the diluted oil, the proportion of said solvent in said slurry being sufficient to reduce the specific gravity of the oil constituent of the sand to about 0.79 to about 0.95, and the amount of the water in the slurry being sufficient to saturate the sand plus an excess sufficient to provide an aqueous barrier between the sand phase and the oil phase under the conditions employed in said centrifugal separations.