Alkali recycle process for recovery of heavy oils and bitumens
AssigneeThe Research Council of Alberta
InventorMichael A. Kessick
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Abstract
Heavy oils, including oil sands, are recovered from mined or in-situ formation by a novel procedure which involves an initial emulsification of the oil with aqueous alkali, usually sodium hydroxide solution, at a pH above about 11. After separation of any residual solid phase, such as sand, the resulting oil-in-water emulsion is inverted by the use of slaked lime to form a water-in-oil emulsion and thereby regenerating part of the sodium hydroxide solution. The water-in-oil emulsion is dewatered to recover the oil phase while the aqueous phase is recycled to the initial emulsification, after removal of clay particles when oil sands are treated.
Claims11
A process for the recovery of oil, which comprises:
- contacting a crude oil having an API gravity value of less than 25.degree. C. and containing groups capable of forming surfactants with water containing at least sufficient sodium hydroxide to provide a pH of the water of at least about 11 so as to form an oil-in-water emulsion having a concentration of about 10 to about 60 wt. % of the crude oil,
- contacting said oil-in-water emulsion with slaked lime in an amount of about 0.02 to about 1 wt. % of the oil in said oil-in-water emulsion and sufficient to invert said oil-in-water emulsion to form a water-in-oil emulsion,
- dewatering the water-in-oil emulsion to recover said oil therefrom, and
- recovering an aqueous sodium medium containing at least a major proportion of said sodium hydroxide from said emulsion inversion and dewatering steps.
Dependencies are inferred from the claim text.