Optimisation of the operating parameters of a thermal plasma system for the conversion of waste containing polychlorinated biphenyls by thermodynamic modelling

Abstract

This paper proposes a mathematical modelling approach to determine the thermodynamic equilibrium of chemical systems in order to optimise the operating parameters of the plasma chemical processes in a low-temperature thermal plasma pilot reactor with a direct current electric arc for the treatment of hazardous waste containing polychlorinated biphenyls. The model is primarily based on the principles of mass action and minimum Gibbs free energy. The obtained results can serve as a basis for multi-criteria optimisation based on ecological aspects, reduction of energy consumption and the possibility of using the produced synthetic gas for energy recovery in the process. The analysis carried out clearly showed the advantages of using water vapour as a plasma working medium and the appropriate mixing of the organic waste containing polychlorinated biphenyls with used engine oil for enriched syngas production. The presented analysis determines the optimal reactor temperature for an ecologically efficient treatment and shows possibilities for energy recovery in the process. The proposed model can also be used for other chemical reactors and for the treatment of other chemical substances.