Effect of reactor structure on removal efficiency of gaseous pollutants using electron attachment mechanism

Abstract

One objective of the present thesis is the design and construction of a gaseous pollutant remover using electron attachment reaction. Low-energy electrons generated in the corona-discharge reactor are captured by electronegative gas molecules, producing negative ions. The ions migrate in the electric field to the anode (reactor wall) and are removed at the wall. A gaseous pollutant remover which mainly consists of the corona-discharge reactor and a high-voltage DC generator was successfully designed and ocnstructed to carry out lab-scale experiments. From the experimental results. it has been found that a higher removal efficiency was obtained as the inlet concentration decreased. Furthermore, the effects of the reactor structure, namely, the cathode diameter, the anode (Reactor) shape and the number of cathodes on the resulting removal efficiency with respect to three dilute gaseous pollutants, methyl iodide, chlorofluorocarbon and acetaldehyde, were investigated experimentally in order to obtain useful guideline for scaling up the device in the future. The results reveal that the thicker the cathode diameter, the higher the removal efficiency. In contrast, the smaller the reactor diameter among three equivolume reactors, the higher the removal efficiency. As for the number of cathodes in a single reactor vessel, the single-cathode reactor exhibits higher removal efficiency than the 5-cathode one.