Influence of Water Vapor on CCl4 and CHCl3 Conversion in Gliding Discharge

The effect of initial concentration of tetrachloromethane and trichloromethane on their conversion in gliding discharge was determined. The conversion of CCl₄ and CHCl₃ was carried out in air containing 20 or 8000 ppm of water vapor. The flow rate of the air containing 1.2, 2.5, or 6.0 vol% of CCl₄ or CHCl₃ was 200 Nl/h. The amount of tetrachloromethane and trichloromethane reacted was determined for a constant value of specific energy which was varied with 2.0 and 4.0 VAh/Nl. The amounts of CCl₄ and CHCl₃ reacted were a linear function of the initial concentration of these compounds in the inlet gas. The results obtained have shown that water vapor present in the air has a favorable effect on the conversion of tetrachloromethane and trichloromethane in gliding discharge.     

Plasma-catalytic Reactor for Decomposition of Chlorinated Hydrocarbons

The conversion of trichloromethane in mixtures with air was investigated under normal pressure in a gliding discharge (GD) reactor operated in both a homogeneous gas system and with a solid catalyst. The Pt catalyst supported by a honey-comb cordierite structure was placed in the reactor below the ends of the electrodes. Cl₂ and HCl were the main products of the CHCl₃ conversion. The presence of CCl₄ was also noted. The influence of the electrode length and the distance between the electrodes in the narrowest section on CHCl₃ conversion was examined. The Pt catalyst revealed some activity in the trichloromethane processing. This resulted in an increased overall CHCl₃ conversion with the portion of CHCl₃ converted to CCl₄ smaller than that in the homogeneous system. The effect of temperature on CHCl₃ conversion was found to be significant.     

Decomposition of Chloromethanes in Gliding Discharges

Gliding discharge plasma was used for decomposition of tetrachloromethane and trichloromethane. Air containing 8000 ppm or 20 ppm of water vapor was the carrier gas. The course and yield of the process were studied as a function of initial concentration of tetrachloromethane and trichloromethane, gas flow rate, and water vapor content. The conversion was high in all cases—it reached 90% for tetrachloromethane and 100% for trichloromethane. The conversion rate of the chloromethane compounds increased with increasing initial concentration of these compounds in the reaction mixture. Changing the water vapor content in the reaction mixture from 20 ppm to 8000 ppm increased the conversion rate of chloromethanes.