| 摘要 |
<p>A system that removes PCBs from synthetic resins in an environmentally safe and economical manner. The system includes a solvent wash subsystem (10) including a first tank (44) to expose the resin particles to a solvent for a first predetermined period of time. In the solvent tank (44), the solvent contacts the resin particles, removing the PCBs. Thereafter, a separator is provided to separate the solvent from the resin particles after removal from the first tank (44). The system also includes a carbon dioxide subsystem (34) where, after separation, the resin particles are exposed to carbon dioxide in a vessel for a second predetermined period of time. Exposure to the carbon dioxide substantially removes any residual solvent and trace amounts of PCBs remaining on the resin particles. In various embodiments, the first predetermined period of time and the second predetermined period of time are selected so that the PCBs on the resin particles are reduced to a predetermined acceptable level, for example, 2.8 million parts per million or less. Exposure to the solvent and the carbon dioxide can be either performed (i) in one continuous cycle for the first period of time and the second period of time respectively; or (ii) in a number of successive cycles, where the sum of the exposure times of the cycles equals the first and second periods of time respectively.</p> |
