Experimental Results Comparing Pulsed Corona and Dielectric Barrier Discharges for Pollution Control

摘要

Nonthermal Plasmas efficiently produce highly reactive chemical species for the destruction of pollutants in gaseous effluents. Two devices commonly used to produce a nonthermal plasma in atmospheric pressure gases are the pulsed corona reactor (PCR) and the dielectric barrier discharge reactor, also referred to as a 'silent discharge plasma' (SDP) reactor. The PCR produces a nonthermal plasma by applying a fast-rising, short duration, high-voltage pulse to a coaxial wire/tube geometry which initiates multiple streamers (electron avalanches) along the length of the tube. The high-energy electrons produced in the streamers create the desired active species while maintaining near ambient neutral gas temperatures. The streamers are extinguished as the energy is depleted in the storage capacitance. The SDP reactor is constructed using either a coaxial or flat-plate electrode geometry with at least one dielectric barrier placed between the high-voltage electrodes, leaving a few mm gap in which the nonthermal plasma is generated. When the breakdown voltage is reached in the gas gap, microdischarge streamers are produced throughout the gap volume which self-terminate when the build up of surface charge on the dielectric reduces the electric field in the gap. A comparison of the results obtained in these devices is presented for various operating conditions and gas pollutants. Our primary interest is to explore whether the added complexity of fast risetime circuits has a payoff in terms of overall chemical-processing efficiency.