Deshalogenation of Sovtol-10 Using a No-Destructive Method: Pilot Plant Design

A practical and efficient treatment of PCBs (polychlorinated biphenyls) in transformer oil by a chemical dechlorination process has been reported. The transformer oil containing commercial PCB mixtures Sovtol-10 was treated by the required amounts of PEG 400 (polyethylene glycol 400) and powdered potassium hydroxide (KOH), along with different reaction times. The reaction of PEG with PCBs under basic condition produces arylpolyglycols and potassium chlorine. The relative efficiencies of PCB treatment process were assessed in terms of destruction and removal efficiency (DRE, %). Under the experimental conditions of KOH/PEG molar ratio 1.2:1, KPEG/oil 22:1 and three hours of reaction at 90 °C, average DRE of PCBs was approximately 99%, showing completely removal of PCBs containing 5-7 chlorines. In the sample remain the congeners 52 and 44 that are not reported as toxic by the WHO (World Health Organization). With the previously reported conditions the scale up of the process was realized.