Destruction of Freon HFC-134a Using a Nozzleless Microwave Plasma Source

In this paper, results of the pyrolysis of Freon HFC-134a (tetrafluoroethane C2H2F4) in an atmospheric pressure microwave plasma are presented. A waveguide-based nozzleless cylinder-type microwave plasma source (MPS) was used to produce plasma for the destruction of Freon HFC-134a. The processed gaseous Freon HFC-134a at a flow rate of 50-212 l min(-1) was introduced to the plasma by four gas ducts which formed a swirl flow in the plasma reactor (a quartz cylinder). The absorbed microwave power was 0.6-3 kW. The experimental results showed that the Freon was converted into carbon black, hydrogen and fluorine. The total conversion degree of HFC-134a was up to 84% with selectivity of 100% towards H-2, F-2 and C-2, which means that there was no conversion of HFC-134a into other hydrocarbons. The Freon destruction mass rate and corresponding energetic mass yield were up to 34.5 kg h(-1) and 34.4 kg per kWh of microwave energy absorbed by the plasma, respectively.