Effect of Hydrocarbons on Plasma Treatment of NOx
Abstract
This paper examines how hydrocarbons affect the non-thermal plasma treatment of NOx in lean-burn engine exhausts. We have found that the NO is mainly oxidized to NO2 by NO + HO2 --> NO2 + OH, NO + RO2 --> NO2 + RO where R is a hydrocarbon radical. The O and OH radicals produced by electron-impact dissociation are consumed mainly by reactions with the hydrocarbons rather than with NO. The hydrocarbons lower the energy cost for the oxidation of NO by converting 0 and OH to HO2; the OH radical is then reproduced when NO is oxidized by HO2. This cyclic process leads to a very efficient utilization of the plasma-produced radicals for the selective partial oxidation of NO to NO2. This result suggests that gas-phase reactions in the plasma alone cannot lead to the chemical reduction of NOx. Any reduction of NOx to N2 can only be accomplished through heterogeneous reactions of NO2 with surfaces or particulates
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1997
- Accession Number
- ADA363447
Entities
People
- B. M. Penetrante
- B. T. Merritt
- G. E. Vogtlin
- M. C. Hsiao
- W. J. Pitz
Organizations
- Lawrence Livermore National Laboratory