Catalytic Performance of MnO_x-WO_3/TiO_2 Catalyst for Selective Catalytic Reduction of NO_x with NH_3 and Its Tolerance Towards SO_2

摘要

The performance of Mn-W/TiO2 for selective catalytic reduction(SCR) of NOx with NH3 and its resistance to different concentrations of SO2 at various temperatures were investigated. The results show that WO3 increased the active sites and enhanced the strength of acid, so it was an effective promoter of MnOx/TiO2. The NOx conversion on Mn-W/TiO2 ranges from 80.3% to 99.6% between 100 °C to 350 °C at GHSV=18900 h-1, while N2 product selectivity changes from 100% to 98.7%. In the presence of 0.01% SO2 and 6% H2O, NOx conversion maintained 98.5% at 120 °C. The influence of more than 0.01% SO2 on the activity of MnOx-WO3/TiO2 will disappear if the temperature rises above 250 °C. By means of heating and sweeping with He, the activity of the catalysts can be recovered. At 300 °C, NOx conversion yielded 99% with 0.07% SO2 and reached the level of commercial V-W/TiO2 catalysts. The Mn-W/TiO2 catalyst showed excellent performance for SCR of NOx with NH3 in a wider range of temperature with strong tolerance to SO2.