DC-Excited Non-Thermal Plasmas for VOC Abatement

Author： Morent Rino Leys Christophe Dewulf Jo Neirynck Dieter Van Durme Jim Van Langenhove Herman

Publisher： Science and Technology Network Inc.

ISSN： 1203-8407

Source： Journal of Advanced Oxidation Technologies, Vol.10, Iss.1, 2007-01, pp. : 127-136

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Abstract

Direct-current (DC) non-thermal plasma technology for the removal of low concentrations of volatile organic compounds (VOC) in waste air is reviewed. Different types of discharge configurations are discussed: pin-to-plate negative corona and glow discharge with transverse flow, hollow needle-to-plate discharge, and positive corona with transverse and axial flow. The removal fraction and the energy efficiency strongly depend on the used technique and pollutant. With DC glow discharge, a maximum removal fraction for 100 ppm trichloroethylene (TCE) of about 47% is obtained at an energy density of only 37 J/L. The corresponding characteristic energy ε₀ is 50 J/L. With a high pressure glow discharge stabilized by a microhollow cathode discharge, the removal for 300 ppm methane in atmospheric pressure air is about 80% for an energy density of 4000 J/L. For benzene (inlet concentration: 296 ppm), the removed fraction is 90% at energy densities of 4000 J/L. The characteristic energy ε₀ for methane is 1667 J/L and for benzene 1250 J/L. Next, hybrid plasma-catalytic reactor concepts aiming to obtain complete oxidation at a reduced energy cost are considered. It is shown that the combination of a plasma with a catalyst is beneficial for the VOC destruction. The VOC destruction efficiencies of a pin-to-mesh system with and without TiO₂ photo-catalyst are compared: the use of the catalyst increases the removal from 70% to 85%. The characteristic energy ε₀ drops from 178 J/L to 132 J/L.