SIMULTANEOUS REMOVAL OF SO_2/NO_x FROM FLUE GAS USING CuO/Al_2O_3 CATALYST/SORBENTS: DEACTIVATION OF SCR ACTIVITY BY SO, AT LOW TEMPERATURES

摘要

The combined removal of SO_2 and NO_x from stationary sources can be achieved with high efficiency using a copper on alumina catalyst/sorbent which acts both as a low-temperature catalyst for the oxidation of SO_2 to SO) and as a sorbent for SO_3 to form surface sulfate species, and also catalyze the reduction of NO_x to N_2 in the presence of NH_3 and O_2. Determination of the effect of sulfur dioxide on SCR activity is very important, because many supported metal SCR catalysts, such as V_2O_5/TiO_2, MnOx/Al_2O_3 and V_2O_5/Al_2O_3, are prone to deactivation by SO_2 at low temperatures. Deactivation of SCR activity on CuO/Al_2O_3 catalyst/sorbent by SO_2 at temperatures lower than 30°C has been identified, but the deactivation mechanism is still not fully understood clear. The purpose of this work is to determine the extent of deactivation of a CuO/Al_2O_3 catalyst/sorbent by SO_2 at low temperatures(200°C ～ 300°C ) to evaluate the deactivation mechanism. Transient experiment, temperature programmed techniques, and physical adsorption are used.