Mobil Oil Corporation

Robert Mitchell Davis

James M Paul

A method for extracting oil from oil-contaminated soil containing 2 to 5 wt. % oil, comprising contacting the oil-contaminated soil with a solvent in the presence of sonic energy in the frequency range of 0.5 to 2.0 kHz. Specifically, a solvent is first mixed with the oil-contaminated soil and the mixture is then formed into a slurry of oil-contaminated soil particles suspended in the solvent. Thereafter the oil-contaminated soil slurry is passed through a shaker screen to remove soil particles greater than 1/4 inch. The oil-contaminated soil slurry containing the smaller soil particles is then fed into the top of a vertically disposed, substantially rectangular shaped, hollow acoustic chamber of uniform cross-section. Fresh solvent is injected into the bottom of the acoustic chamber that flows upwardly through the acoustic chamber. The fresh solvent is injected at a rate low enough whereby the oil-contaminated soil particles fall by gravity through the upwardly flowing solvent. The oil-contaminated soil particles and solvent in the acoustic chamber are subjected to acoustic energy in the frequency range of 0.5 to 2.0 kHz displaces the oil from the oil-contaminated soil particles that is dissolved by the upwardly flowing solvent without cavitation of the solvent. The substantially oil-free soil particles containing only 0.2 to 0.4 wt. % oil are recovered from the bottom of the acoustic chamber and spread over the land for land farming. The present method may also be used for extracting oil from oily sludge or oil-based drill cuttings.

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Ft. Worth, TX, United States of America

Robert Mitchell Davis