Thesis (M.Eng.)--Chulalongkorn University, 1998

This research investigated the effect of tungsten and potassium on the V2O5/TiO2 catalyst with high vanadium loading for selective catalytic reduction (SCR) of NOx with NH3 reaction. The main objective of this research is to explore the loading effect, loading sequence of tungsten and potassium, the catalytic behavior of the catalysts also effect of SO2 and water. From the results, 5 wt.% WO3 is the optimum loading on based catalyst due to highest activity. Moreover, the loading sequence of both W and K introduced on V2O5/TiO2 catalysts also has some effect on the catalytic activity of the catalysts. Co-loading method shows the highest activity compared with other methods. SO2 increases the acid property on catalyst surface, while water causes competitive adsorption on active sites. On the other hand, tungsten increases the acid strength on catalyst surface. Consequently, enhances the activity in SCR reaction at lower temperature including accelerates the ammonia oxidation reaction at higher temperature too. In contrast, potassium decreases the acid strength on catalyst surface. Therefore, the activity of the catalyst with potassium is lower at lower temperature. However, potassium can inhibit the oxidation of ammonia at higher temperature. This is an advantage of potassium which is contained in the catalyst.