DESTRUCTION OF HAZARDOUS AIR-POLLUTANTS USING A FAST RISE-TIME PULSEDCORONA REACTOR

Increasingly stringent environmental regulation imposed on both the mi litary and civilian sectors has created a growing demand for alternati ve abatement methods for a variety of hazardous compounds. One alterna tive, the nonthermal plasma, shows promise of providing an efficient m eans for the destruction of dilute concentrations of hazardous air pol lutants. The Dahlgren Laboratory of the Naval Surface Warfare Center h as extensively investigated one type of nonthermal plasma discharge, t he pulsed corona reactor, for the destruction of volatile organic comp ounds and chemical warfare agents. In this reactor, a fast rise time ( similar to 10 ns), short duration (<100 ns), high-voltage pulse is rep etitively delivered to a wire-cylinder electrode geometry, thereby pro ducing a multitude of streamer discharges along its length. The result ing nonthermal plasma contains highly reactive chemical radicals which can interact with and destroy the hazardous molecules entrained in th e ambient atmosphere flowing through the reactor volume. Increased ele ctrical efficiency was obtained using a combination of high efficiency constant-current capacitor-charging high repetition-rate spark gap sw itching, and resonant energy transfer to the reactor. Promising result s have been obtained for toluene, methylene chloride, and dichlorodifl uoromethane in air at concentrations of a few hundred parts per millio n. The device has been operated at voltages up to 30 kV, pulse repetit ion rates up to 1.4 kHz, and flow rates up to 60 l/min. Detailed elect rical measurements have been made to properly characterize the electri cal properties of the pulsed corona reactor and to validate subsequent improvements in the reactor energy efficiency. (C) 1998 American Inst itute of Physics.