Separation of oils from solids
AssigneeUnion Oil Company of California
InventorDonald C. Van Slyke
Life of this patent
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Abstract
Drill cuttings are cleaned of oil-based drilling mud and oil using a cleansing agent, such as a C6-C10 carboxylic acid, that is preferentially oil soluble at one pH and preferentially water soluble at another pH. The oily cuttings are treated with the carboxylic acid and then washed with an aqueous, alkaline washing solution, which converts the carboxylic acid to its water soluble salt and, with vigorous agitation, lifts most of the oil from the cuttings. In other embodiments, the process is used for cleaning oil-contaminated soil, sand, and gravel, and for separating the oils from the solids in oily sludges.
Claims18
A method for cleaning a sludge comprising hydrocarbon-contaminated particulate solids, which comprises:
- (a) mixing said sludge with a carboxylic acid having at least 6 carbon atoms to form a non-aqueous liquid phase comprising hydrocarbon and carboxylic acid;
- (b) separating the non-aqueous liquid phase from the particulate solids;
- (c) washing the separated solids with an aqueous alkaline wash for removing residual hydrocarbon and carboxylic acid, and recovering cleaned solids;
- (d) contacting the separated non-aqueous liquid phase with an aqueous alkaline wash for extracting carboxylic acid into an aqueous phase as a carboxylate salt;
- and
- (e) acidifying the aqueous phase for regenerating the carboxylic acid.
A method for cleaning a sludge comprising (i) oil, (ii) water, and (iii) solids, the method comprising the steps of:
- (a) contacting the sludge with a carboxylic acid to form a sludge-carboxylic acid combination;
- (b) separating the sludge-carboxylic acid combination formed in step (a) into an oil-, water-, and carboxylic acid-containing first liquid phase and a solids-, oil-, and carboxylic acid-containing solid phase;
- and
- (c) contacting the solids-, oil-, and carboxylic acid-containing solid phase with a reagent for converting carboxylic acid to a water-soluble carboxylate salt.
A method for cleaning a sludge comprising (i) oil, (ii) water, and (iii) solids, the method comprising the steps of:
- (a) contacting the sludge with a carboxylic acid to form a sludge-carboxylic acid combination;
- (b) separating the sludge-carboxylic acid combination formed in step (a) into an oil-, water-, and carboxylic acid-containing first liquid phase and a solid-, oil-, and carboxylic acid-containing solid phase;
- and
- (c) contacting the solid-, oil-, and carboxylic acid-containing solid phase with an aqueous base solution for converting carboxylic acid to its corresponding water-soluble carboxylate salt.
Dependencies are inferred from the claim text.