Evaluation of a Prototype SF₆ Purification System for Commercialization

Evaluation of a Prototype SF₆ Purification System for Commercialization

Korea Electric Power Corporation (KEPCO) uses large amount of SF₆, one of the potent greenhouse gases, in electric equipment for electrical insulation. KEPCO is developing SF₆ recovery and purification technology to minimize the release of SF₆ into the environment, to secure certified emission reduction, and to save purchase cost of new SF₆ by reusing the refined SF₆. A prototype SF₆ purification system using cryogenic solidification technology has been built in demonstration scale. To evaluate the feasibility of the commercialization, the system has been operated to purify large amount of used SF₆ in a long-term operation and the performance has been economically evaluated. The system was stable enough for commercial operation such that it was able to purify 5.4 tons of used SF₆ from power transmission equipment in 2-month operation. Over 99% of the SF₆ was recovered from the used gas and the purity of the purified gas was over 99.7 vol%. The operation cost, which is the cost of refrigerant (liquid nitrogen), electricity and labor, per kilogram of purified SF₆ was 6,526 KRW. Considering the price of new SF₆ in Korea is about 15,000 KRW per kilogram this year, about 56% of the purchase cost can be saved.