Abstracts Physics

A feasibility study of adaptive plasma-assisted incineration

by Julie. Filion

Rising awareness in the need for environmental protection has brought into question the adequacy of conventional hazardous waste treatment operations. Regulatory standards are increasingly strict, and there is growing concern over the safety of incineration facilities. This research project examines the technoeconomic potential of thermal plasma technology in this context. Adaptive Plasma-Assisted Incineration (APAI) is a novel concept for secondary gas treatment in hazardous waste incineration. As an energy source for waste destruction, a thermal plasma can provide conditions far higher in temperature and in reactivity than those obtained using a combustion flame. Thus, the plasma is more effective at destroying hazardous materials, albeit at a higher cost. APAI features a thermal plasma afterburner with continual on-line optical monitoring of the gas product and feedback optimization of the plasma conditions. This approach allows complete destruction of persistent organic compounds and cost-effective response to feed load variations. The process supplements conventional incineration techniques with the effectiveness and flexibility of thermal plasma treatment. The main objectives are to reduce the risk of harmful emissions during hazardous waste incineration and to facilitate compliance with new environmental regulations. In this project, the technical feasibility of APAI was demonstrated experimentally using a laboratory-scale plasma afterburner model. The work focused on the development of a spectroscopic monitoring procedure and on the application of optimization techniques for cost-effective operation of the model system. The techno-economic potential and limitations of APAI were addressed in a conceptual study. Preliminary designs and cost estimates were developed for specific applications. The costs of plasma-assisted and conventional methods were compared for contaminated soil remediation (by incineration and desorption) and for organic liquid waste destruction. Economically, APAI appears uncompetitive at the present time. However, it remains a promising alternative in view of ongoing environmental policy changes and developments in plasma technology.