Comparison of reactor performance in the nonthermal plasma chemical processing of hazardous air pollutants

The performance of three different types of plasma reactors such as ferroelectric packed-bed (FPR), pulsed corona (PCR), and silent discharge (SDR) were compared in the decomposition of trichloroethylene (Cl₂C=CHCl, TCE), bromomethane (CH₃Br), and tetrafluoromethane (CF₄). Irrespective of reactors, hazardous air pollutant (HAP) reactivity in dry N₂ decreased in the order: TCE>CH₃Br>CF₄. Similar byproducts were obtained with any of the above reactors, and similar trends were observed in the HAP decomposition rate-retarding effect by water. Only for SDR, TCE decomposition was accelerated by O₂ in the background gas. The most plausible active oxygen species is considered to be the triplet oxygen atom. In the reaction systems where chemically induced decomposition of HAPs can occur, as in the case of TCE, PCR is expected to exceed FPR and SDR in performance. In the cases of CH₃ Br and CF₄, residence time has been the most important factor governing their decomposition rates, and FPR and SDR have shown higher performance than PCR