E.i. Dupont De Nemours and Company

Conoco Inc.

Robert B Ramsey, Jr

Robert E Williams

David A Flanigan

Olaf M Stokke

John Huycke

An improved vapor degreaser characterized by a deep freeboard zone (i.e., freeboard to width ratio of 1.0 to 2.3) containing a three-stage condenser/heat exchanger configuration comprising: a water-cooled lower primary exchanger operating above 32.degree. F. to effect condensation of the bulk of the vapor generated by the boiling sump and a combination of an intermediate exchanger above, but preferably overlapping, the primary exchanger and a dehumidifying third exchanger position just below the top lip of the degreaser, both operating at a temperature below 32.degree. F. (preferably +10.degree. to -30.degree. F.) to effect a reduction in the vapor concentration gradient that controls the rate of vapor diffusion through the freeboard zone. The improved vapor degreaser is particularly useful in reducing vapor losses when using low boiling solvents.

Vapor control system for vapor degreasing/defluxing equipment

An improved vapor degrease characterized by a deep freeboard zone (i.e., freeboard to width ratio of 1.0 to 2.3) containing a three-stage condenser/heat exchanger configuration comprising: a water-cooled lower primary exchanger operating above 32.degree. F. to effect condensation of the bulk of the vapor generated by the boiling sump and a combination of an intermediate exchanger above, but preferably overlapping, the primary exchanger and a dehumidifying third exchanger position just below the top lip of the degreaser, both operating at a temperature below 32.degree.F. (preferably +10.degree. to -30.degree.F.) to effect a reduction in the vapor concentration gradient that controls the rate of vapor diffusion through the freeboard zone. The improved vapor degreaser is particularly useful in reducing vapor losses when using low boiling solvents.

1,1-dichloro-2,2,2-trifluoroethane or 1,1-dichloro-1-fluoroethane are employed as solvents to remove oleophylic material from mineral particulates. In one aspect the method of this invention includes the steps of transporting oil-based mud-laden cuttings to a solid feed tank wherein the oil-based cuttings are subjected to turbulent mixing to leave the surface of the cuttings substantially free of oil. The cuttings are then subjected to countercurrent flow of solvent in order to separate oily solvent and fines smaller than a chosen diameter from the heavier solids. The heavier solids are cleaned of any remaining oil-based muds, separated from cleaning solvent and ultimately returned to the sea environment.

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Wilmington, DE, United States of America

Robert B Ramsey, Jr