Influence of Steam and Sulfide on High Temperature Selective Catalytic Reduction

Abstract

The influences of steam and sulfide on the efficiency of NOx reduction using ammonia (NH3) over the nanometer-class V-W/Ti catalyst in conditions of high temperature is experimentally investigated using a steady-flow reactor. The results showed that selective catalytic reduction (SCR) is inhibited by H2O at low temperature, but higher NO conversion efficiency is achieved at high temperature since the reaction of NH3 oxidized by O2 to NOx is inhibited by H2O. The activity of SCR is promoted by SO2 in the temperature range of 200~500° C, the NO conversion efficiency was improved to 98% from 94% by adding SO2. SCR would be improved at 350~500°C when H2O and SO2 exist at the same time. Furthermore, the positive influence to the NOx conversion was proved in the presence of H2O and SO2 as a result of the European Stationary Cycle test.