PLASMA THERMAL DESTRUCTION AND RECOVERY TREATMENT OF PCBCONTAMINATED LIQUIDS AND SOLIDS

摘要

A test program, supported by 3D thermo-fluid-chemical modeling, was conducted to demonstrate the ability of thermal plasma technology to achieve >99.9999% Destruction and Removal Efficiency (DRE) for polychlorinated biphenyl (PCB) contaminated liquids and electrical components. The conditions of all effluent streams (gas, water and solids) for purposes of air and water discharge permit compliance were documented by third party, independent sampling and analytical service contractors. Results showed that the process destroyed PCBs to greater than 6 nines DRE (>99.9999%) and met all air and water discharge standards. Glassy slag residue from contaminated solid components was non-hazardous and metal collected from the melting process recyclable. A simulation capability was developed to predict the behavior of the plasma process for PCB-contaminated waste remediation. The geometric, flow, thermal and chemical characteristics of the plasma furnace were modeled using a finite-volume, numerical solver with a multi-block, structured/unstructured hybrid grid. A series of reaction steps were utilized in which a representative, PCB-like CxHy molecule decomposed via thermal energy input from the plasma. Various reaction steps proceed depending upon calculated, local temperatures. Unique traces of fluid stream paths were mapped from the PCB oil volatilization region to the furnace exhaust, creating a unique "temperature/time-of-flight" history. These trace records represented unique trajectory histories to which the decomposition model responded. DRE's >99.99999% were computed, in substantial agreement with measurements. This test and analysis effort provides a predictive tool whereby sub/pilot scale data can be extended to PCB destruction processes for the high feedrates and concentrations required for future commercial systems.