Chlorofluorocarbons undergo interconversion during destruction in an argon arc plasma, so that, for example, in the exhaust gas from destruction of CCI2F2, CCIF3 is found to be the major residual ozone depleting substance: as electron capture detectors are lo4 times less sensitive for CCIF3, compared with CCI2F2, although these gases have the same ozone depleting potential, analysis of exhaust from destruction of chlorofluorocarbons is therefore not a trivial matter of determining only the level of input chlorofluorocarbon remaining.

The electrical and thermal conductivity and the net radiation emission of a sulfur hexafluoride plasma were measured for temperatures up to 22 500 K at 1, 4 and 8 bar. These measurements were made on wall stabilized cascade arcs of 3 and 5 mm diameter using spectroscopy. The electrical conductivity was in fair agreement with the theory but was found to be pressure dependent. The thermal conductivity k, at 1 bar pressure was in good agreement with the other experimental results of Frie and Motschmann, but was higher by a factor of three as compared to the theoretical estimates of Frost and Liebermann. At 4 and 8 bar the values of k were higher by a factor of six and eight, respectively. The high value of the thermal conductivity was attributed to the contribution of the thick radiation absorption within the arc column. These experimental measurements have shown for the first time, the strong pressure dependence of the apparent thermal conductivity. The net radiation emission u was also found to be higher, by up to a factor of two, as compared to the theoretical estimates of Liebermann and Lowke.

The heat flux and destruction and removal efficiency (DRE) measurements have been made on 100, 150 and 200 mm diameter plasma reactors to optimize the performance. The DRE was measured for pressure and gas atomization techniques of waste injection using both argon and CO 2 gases. As a result, the design of the reactor was optimized and the waste throughput was increased by ∼17% with improved destruction performance. The 150 mm diameter reactor was found to perform better using gas atomization of feed injection using carbon dioxide at the given power and waste feed rate.

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