Storage-reduction strategy for NOx reduction from gas turbine exhaust with W–Ti-CeOx catalyst in natural gas power plants

Abstract

Traditional vanadium-based selective catalytic reduction (SCR) deNOx catalyst can hardly adapt to the gas conditions (much high NO2/NOx ratio at lower temperature) of the start-up and low loading periods for a gas turbine. Therefore, a W–Ti-CeOx catalyst with NOx storage and reduction (NSR) function was developed in this work for gas turbine exhaust NOx elimination. The experimental results reveal that W–Ti-CeOx catalyst exhibits high NO2 adsorption capacity at relatively low temperature while that is quite low for V–W/TiO2. The abundant surface Ce3+ species can be mainly responsible for its high adsorption ability owing to the reaction between NO2 and Ce3+ to form nitrate/nitrite species and NO. Meanwhile, the adsorption capacity of W–Ti-CeOx can easily regenerate at medium–high temperature and NH3-SCR reaction. Furthermore, W–Ti-CeOx also shows good NH3-SCR activity, which can fulfill the deNOx process at high temperature. The addition of W and Ti into ceria can enhance the surface acidity and redox ability, thereby increasing the SCR activity. This work proposes a novel storage-reduction strategy for NOx elimination throughout the operation of gas turbines.