Method for the solvent extraction of polychlorinated biphenyls

Claim 2

A process for the removal of polychlorinated biphenyls from a fluid containing the same which comprises: contacting said fluid with polyethylene glycol for a period of time sufficient for said glycol to selectively extract at least a portion of the chlorinated biphenyl compounds from said fluid; and separating the polyethylene glycol and extracted polychlorinated biphenyls from said fluid.

Claim 3

The process of claim 1 wherein the fluid is a dielectric fluid.

Claim 4

The process of claim 1 wherein the fluid comprises a hydrocarbon oil.

Claim 5

The process of claim 1 wherein the fluid is a transformer oil.

Claim 6

The process of claim 1 wherein the polyethylene glycol has an average molecular weight of from about 400 to about 20,000.

Claim 7

The process of claim 1 wherein the polyethylene glycol is a liquid.

Claim 8

The process of claim 1 wherein the polyethylene glycol is a solid.

Claim 9

The process of claim 6 wherein the process is repeated a sufficient number of times to reduce the poly-chlorinated biphenyl content of the fluid to a maximum of 50 ppm.

Claim 10

The process of claim 8 wherein the volume of the polyethylene glycol employed in each repetition is about the same as the volume of the fluid treated.

Claim 11

The process of claim 6 comprising the additional step of solvent extracting the polychlorinated biphenyl from the separated polyethylene glycol with a non-polar solvent and separating the resulting non-polar solvent polychlorinated biphenyl extract from said polyethylene glycol.

Claim 12

The process of claim 10 comprising the additional step of removing the cyclohexane from said non-polar solvent-polychlorinated biphenyl extract and dehalogenating the remaining polychlorinated biphenyl.

Claim 13

The process of claim 11 wherein dehalogenation is effected by treating said polychlorinated biphenyl with a reagent formed by the reaction of an alkali metal or an alkali metal hydroxide, with polyethylene glycol and oxygen.

Claim 14

The process of claim 7 comprising the additional step of solvent extracting the polychlorinated biphenyl compound from the separated polyethlene glycol with a non-polar solvent and separating the resulting non-polar solvent-polychlorinated biphenyl extract from said polyethylene glycol.

Claim 15

The process of claim 13 comprising the additional step of removing the cyclohexane from said non-polar solvent-polychlorinated biphenyl extract and dehalogenating the remaining polychlorinated biphenyl.

Claim 16

The process of claim 14 wherein dehalogenation is effected by treating said polychlorinated biphenyl with a reagent produced by the reaction of an alkali metal or an alkali metal hydroxide, with polyethylene glycol and oxygen.

Claim 17

A process for the removal of polychlorinated biphenyl from the dielectric fluid of an electrical transformer which comprises: drawing off dielectric fluid from said transformer; contacting said drawn off fluid with polyethylene glycol for a period of time sufficient for said glycol to selectively extract at least a portion of the polychlorinated biphenyl from said fluid; separating from said fluid the polyethylene glycol containing extracted polychlorinated biphenyl; and returning said fluid to said transformer.

Claim 18

A process for the removal of polychlorinated biphenyl from the dielectric fluid of an electrical transformer which comprises: drawing off dielectric fluid from said transformer; contacting said drawn off fluid with polyethylene glycol for a period of time sufficient for said glycol to selectively extract at least a portion of the polychlorinated biphenyl from said fluid; separating from said fluid the polyethylene glycol containing extracted polychlorinated biphenyl; and returning said fluid to said transformer.

Claim 19

The process of claim 16 wherein the transformer is an operating transformer.

Claim 20

A process for removing and detoxifying a polychlorinated biphenyl present in the dielectric fluid of an electrical transformer which comprises: drawing off dielectric fluid from said transformer; contacting said drawn off fluid with polyethylene glycol in a primary extraction operation for a period of time sufficient for said glycol to selectively extract at least a portion of the chlorinated biphenyl from said fluid; separating from said fluid the polyethylene glycol containing extracted polychlorinated biphenyl; returning said fluid to said transformer; solvent extracting with cyclohexane the chlorinated biphenyl compound from the polyethylene glycol in a secondary extraction operation to form a cyclohexane-polychlorinated biphenyl extract; separating said cyclohexane-polychlorinated biphenyl extract from said polyethylene glycol and recycling the latter to said primary extraction operation; removing cyclohexane from said cyclohexane-polychlorinated biphenyl extract and dehalogenating the remaining polychlorinated biphenyl; and recycling said cyclohexane to said secondary extraction operation.

Claim 21

A process for removing and detoxifying a polychlorinated biphenyl present in the dielectric fluid of an electrical transformer which comprises: drawing off dielectric fluid from said transformer; contacting said drawn off fluid with polyethylene glycol in a primary extraction operation for a period of time sufficient for said glycol to selectively extract at least a portion of the chlorinated biphenyl from said fluid; separating from said fluid the polyethylene glycol containing extracted polychlorinated biphenyl; returning said fluid to said transformer; solvent extracting with cyclohexane the chlorinated biphenyl compound from the polyethylene glycol in a secondary extraction operation to form a cyclohexane-polychlorinated biphenyl extract; separating said cyclohexane-polychlorinated biphenyl extract from said polyethylene glycol and recycling the latter to said primary extraction operation; removing cyclohexane from said cyclohexane-polychlorinated biphenyl extract and dehalogenating the remaining polychlorinated biphenyl; and recycling said cyclohexane to said secondary extraction operation.

Claim 22

The process of claim 18 wherein dehalogenation is effected by treating said polychlorinated biphenyl with a reagent produced by the reaction of sodium, or sodium hydroxide, with polyethylene glycol and oxygen.

Claim 23

A process for removing and detoxifying polychlorinated biphenyls present in a fluid containing the same which comprises contacting the fluid with a treating composition comprising polyethylene glycol and a dehalogenation reagent produced by the reaction of an akali metal or alkali metal hydroxide, with polyethylene glycol and oxygen, and extracting the polychlorinated biphenyls in the fluid into said composition; introducing oxygen into said composition containing said polychlorinated biphenyls, thereby to effect dehalogenation of the polychlorinated biphenyls by the dehalogenated reagent; and separating any remaining treating composition and components thereof and, dehalogenation reaction products from said fluid.

Claim 24

A process for removing and detoxifying polychlorinated biphenyls present in a fluid containing the same which comprises contacting the fluid with a treating composition comprising polyethylene glycol and a dehalogenation reagent produced by the reaction of an akali metal or alkali metal hydroxide, with polyethylene glycol and oxygen, and extracting the polychlorinated biphenyls in the fluid into said composition; introducing oxygen into said composition containing said polychlorinated biphenyls, thereby to effect dehalogenation of the polychlorinated biphenyls by the dehalogenated reagent; and separating any remaining treating composition and components thereof and, dehalogenation reaction products from said fluid.

Claim 25

The process of claim 20 wherein said treating composition includes a surfactant of the general formula, H--O(--CH 2 --CH 2 --O)--R, wherein x is ≧2 and R represents an alkyl group having 12 or more carbon atoms, an aralkyl group, an ester residue or a polypropylene glycol group.

Claim 26

The process of claim 20 wherein the fluid is a dielectric fluid.

Claim 27

The process of claim 20 wherein the fluid comprise a hydrocarbon oil.

Claim 28

The process of claim 20 wherein the fluid is a transformer oil.

Claim 29

The process of claim 20 wherein the polyethylene glycol has an average molecular weight of from about 400 to about 20,000.

Claim 30

The process of claim 25 wherein the process is repeated a sufficient number of times to reduce the polychlorinated biphenyl content of the fluid to a maximum of 50 ppm.

Claim 31

The process of claim 10, wherein the non-polar solvent is cyclohexane.

Claim 32

The process of claim 11, wherein the non-polar solvent is cyclohexane.

Claim 33

The process of claim 13, wherein the non-polar solvent is cyclohexane.

Claim 34

The process of claim 14, wherein the non-polar solvent is cyclohexane.

Claim 35

The process of claim 12, wherein the alkali metal is sodium and the alkali metal hydroxide is sodium hydroxide.

Claim 36

The process of claim 15, wherein the alkali metal is sodium and the alkali metal hydroxide is sodium hydroxide.

Claim 37

The process of claim 20, wherein the alkali metal is sodium and the alkali metal hydroxide is sodium hydroxide.