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Plasma Chemistry in the Pulsed Corona Reactor
In this example of a chemical reaction in a discharge-based nonthermal plasma reactor, a burst of high-energy electrons (1-10 eV) is created in an ambient gas volume consisting of air or nitrogen into which a pollutant concentration of a few hundred parts per million has been introduced. Even though the electrons are relatively short-lived (nanoseconds) under atmospheric pressure conditions and rarely interact directly with the offending molecules, they do collide with the dominant background molecules, creating chemically active species known as radicals. These radicals can have relatively long lifetimes (milliseconds) and can react selectively with the pollutant molecules, breaking them down into less harmful or more easily handled compounds.
The reactions take place without a significant increase in the temperature of the background gas. Further efficiency gains are achieved because only a brief burst of short-lived electrons is required to produce the relatively long-lived radicals. The discharge-based nonthermal plasma reactor can thus result in significant energy savings.
Published in the Spring 1996 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.