Conception et réalisation d'un réacteur plasmagéne pour le traitement des films liquides

Abstract

This paper describes a novel gliding Arc discharge reactor producing a non-thermal plasma at atmospheric pressure in humid air. The ionized gas is generated in a spray-tower absorber for the treatment of organic pollutants. The reactor configuration enables the plasma-degradation of micro-droplets effluents in the spatial post-discharge mode. This type of design allows to exclude the direct contact between the plasma plume and the liquid to be treated in order to avoid the liquid heating and the flame extinction problems. A hydrodynamic study coupling ‘Navier-Stokes’ equations and those of ‘Convection-Diffusion’ allowed to calculate the concentration profiles and the droplet falling velocity. The stripping of phenol was studied to valid the hydrodynamic approach. Experiences and simulations showed that after 1 h of treatment, only 5% of the compound was transferred into the plasma phase. The spatiality of the novel reactor allowed a degradation rate of 100% for catechol after 38 min of plasma-treatment. For 4-nitrophenol, the degradation rate reached 90% after 120 min. Phenol and its by-products degradation were totally degraded by combining the spatiality of the reactor and the temporal post-discharge. A degradation mechanism was proposed and a plasmachemical reaction in relation with the pernitrousacid species was confirmed.