Decomposition of dichloromethane in a wire-in-tube pulsed corona reactor.

Decomposition of low concentration dichloromethane in nitrogen-based gas was experimentally investigated by a wire-in-tube pulsed corona reactor. Maximum decomposition was found in pure nitrogen, and the decomposition decreased with the increase of oxygen concentration in the gas. The major product detected by FTIR from the decomposition of dichloromethane without oxygen participation was HCI, while CO, CO2, COCl2, and NOx were the main detected products in the presence of oxygen. Aiming at removing the unwanted byproducts from the decomposition reaction, a combination of corona discharge and gas absorption was devised by coating a thin layer of Ca(OH)2 on the inner wall of the corona reactor. It was demonstrated that this kind of combination was capable of scavenging the products of phosgene and nitrogen oxides from the plasma decomposition of dichloromethane.