Publications

Selected publication  

Machala Z., Morvová M., Marode E., Morva I.: Removal of cyclohexanone in Transition Electric Discharges at Atmospheric Pressure, J.Phys. D: Appl.Phys., Vol.33 No 24, 3198-3213 (2000).
citations: 36  

Abstract

Two new types of streamer-induced electric discharges operating in the non-uniform electric field and at atmospheric pressure were applied to the removal of VOC (cyclohexanone) at various concentrations (600-6000 ppm) with varying gas flow rates. The first type is a pulseless d.c. discharge with physical properties corresponding to the glow discharge. The second one, also supplied by a d.c. high voltage of both polarities, is a spontaneously pulsing discharge operating in regime of streamer-to-spark transition, the spark phase being too short to reach LTE conditions. Both discharges may generate a non-thermal plasma, as resolved from their rotational and vibrational temperatures.The influences of these discharges on cyclohexanone removal were compared. Achieved removal efficiencies were about 50-60 %, energy costs in the range 16-100 eV/molecule at various energy densities. CO2 and other gaseous products were minor, dominant products appeared in the condensed phase, especially in the spontaneously pulsing transition discharge.We have tried to explain some of the plasmo-chemical processes induced by the discharges and heterogeneous effects of the copper electrode surface. The role of active nitrogen and formation of NCO radical may be key factors leading to the formation of the condensation product based on amino acids, here identified, as well as in the overall energy cycle resulting in low energy costs of the process.The small pilot-scale reactor based on the spontaneously pulsing transition discharge regime has been successfully applied to the removal of cyclohexanone in the mixture with other VOC with no noxious gas output. This validates a possibility of application of such type of the reactor for larger scales.