Effects of Hydrocarbons and Water Vapor on NOx Using V2O5−WO3/TiO2 Catalyst Reduction in Combination with Nonthermal Plasma

Abstract

The effects of hydrocarbons and water vapor on a combined deNOx process, which consists of nonthermal plasma oxidation and V2O5−WO3/TiO2 selective catalytic reduction (SCR), are investigated. Test results show that the fast SCR reaction, which needs equimolar amounts of NO and NO2, plays a dominant role in reducing NOx under relatively low-temperature conditions, i.e., 150−200 °C. Under such low-temperature conditions, the oxidation of NO to NO2 induced by nonthermal plasma is useful in controlling NO2 fractions in NOx for the fast SCR reaction. The role of the fast SCR reaction, however, decreases when C3H6 is supplied to the process as simulated hydrocarbons in diesel exhausts. Test results yielded the following conclusions: (1) C3H6 leads to the production of aldehydes in the nonthermal plasma reactor. (2) The NO2 fraction in the SCR reactor decreases as a result of aldehyde production, leading to a diminished role of the SCR reaction. This reduction in NO2 is predominant when water vapor is not added...