Hazardous waste treatment and valuable products recovery with a thermal pulsed-plasma technology

Material cracking, or decomposition, is a basic and essential process in the chemical industries. This process is a major energy consumer and a cause of environmental pollution. A new, efficient and environmentally friendly technique and equipment that can be used in a closed-loop process for the treatment and recovery of materials is proposed. The idea is to decompose a material using a high-energy pulsed-plasma jet. The plasma specific features enable a most efficient radiative heat transfer to the treated material bed. Therefore, enhanced energy transfer to selected chemical bonds is achieved. The process can be defined as a highly efficient photolysis. Proof-of-concept tests were carried out on 1,2-Dichloroethane (DCE). The material was fed in batches of a few grams each. A total decomposition of the DCE was achieved with less than 60% of the energy consumption required in a conventional treatment. A modular transportable laboratory has been constructed in the framework of 4^th European Brite Euram R&D program. It comprises a 30 kW pulsed power supply featuring an all-solid state switching system, confined plasma discharge injector, reactor and gas handling and monitoring systems. The expected treatment capacity is 5-10 kg/hour of fluid waste. The plasma injector is designed to operate in repetitive mode with expected lifetime of 10⁵ pulses. Simulations and experimental characterization of major components are presented. It is expected that the proposed method will be the best available technology for many fluid wastes.