US 4,790,337 A · Apparatus for removing PCB's from electrical apparatus

Abstract

Disclosed is a process for removing polychlorinated biphenyls from electrical apparatus, particularly transformers, to achieve concentration levels of 50 ppm or less as required by the EPA. A dielectric fluid having a relatively low boiling point as compared to polychlorinated biphenyls and other contaminants and in which PCB's are soluble is selected. There is an external cooling loop through which the dielectric fluid is circulated maintaining the temperature and pressure of the transformer within its design limits. There is an external distillation loop where the liquid removed from the transformer is heated to boiling point of the selected dielectric fluid thereby vaporizing the dielectric fluid and leaving the polychlorinated biphenyls in liquid phase in the distillation vessel. The dielectric fluid vapor is then condensed and returned to solubilize remaining PCB's in the transformer.

Claims42

Dependent claims

An apparatus for removing contaminants such as polychlorinated biphenyls from transformers and from a dielectric fluid/solvent contained therein comprising:

(a) a charge of a dielectric fluid/solvent in liquid state sufficient to substantially fill the transformer to an operable level, the polychlorinated biphenyls being soluble in said dielectric fluid/solvent, said dielectric fluid/solvent selected from the group consisting of:
a. trichlorotrifluoroethane;
b. perchloroethylene;
c. perfluorocyclic ether;
d. perfluorobicyclo-(2.2.1)heptane;
e. perfluorotriethyl amine;
f. monochloropentadecafluoroheptane;
g. perfluordibutyl ether;
h. perfluoro-heptane;
i. mixtures of trichlorotrifluoroethane and perchloroethylene;
(b) a distillation means receiving said dielectric fluid/solvent having polychlorinated biphenyls dissolved therein;
(c) means for maintaining the transformer substantially filled to its operational level with said dielectric fluid/solvent in liquid state.

9 more elements

An apparatus for decontaminating an electrical apparatus, comprising:

a transfer line for substantially continuously withdrawing dielectric liquid containing a contaminant selected from polychlorinated biphenyls and trichlorobenzene from an electrical apparatus, said contaminant being readily soluble in said dielectric and having a substantially higher boiling point in relation thereto;
a distillation chamber operable to receive said contaminated dielectric and to boil said dielectric and thereby separate said contaminated dielectric into a vapor phase substantially free of said contaminant and a liquid phase in which said contaminant is concentrated;
a control valve positioned in said transfer line for controlling transfer of said contaminated dielectric to said distillation chamber to maintain said liquid phase therein at an operable level, said control valve being responsive to said level;
a waste receptacle for periodically receiving said liquid phase from said distillation chamber;
means responsive to the temperature of said distillation chamber for transferring said distillation chamber liquid phase to said waste receptacle;
a condenser for receiving and condensing said vapor phase from said distillation chamber to produce liquid dielectric substantially free of said contaminant;
a condensate tank for receiving said liquid dielectric from said condenser;
means for recirculating liquid dielectric from said condensate tank to said at a rate sufficient to maintain an operable level of liquid dielectric in said electrical apparatus;
and
a charge of said dielectric liquid in the electrical apparatus and the decontamination apparatus sufficient for substantially continuous operation of said electrical apparatus and said distillation chamber.

7 more elements

Dependencies are inferred from the claim text.

Apparatus for removing PCB's from electrical apparatus

Life of this patent

Apparatus for removing PCB's from electrical apparatus

Life of this patent

Abstract

Claims42