| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and an apparatus for desorbing polychlorinated biphenyls(PCBs) from used active carbon in a manner that the residual PCBs can be eliminated without fail while any harmful products are prevented from being formed. SOLUTION: Active carbon on which PCBs have been adsorbed is fed into an air-tight reaction treater 1 and is subjected to a pretreatment for removing adsorbed water, adsorbed volatile organic gases, and air at 200 deg.C or below. The treater 1 is evacuated and is brought into an adiabatic state. The carbon is then gradually heated by allowing a current to directly flow into electrodes 8 and 9, whereupon the PCBs are removed and recovered in turn as a result of their evaporative desorption in order of increasing boiling points after the lapse of a definite retention time at every specified temperature rise in the range of 200-600 deg.C. A minor amount of the residual PCBs are gasified or carbonated at 750 deg.C or below. |
