Effect of Sodium on Simultaneous Removal of SO_2 and NO from Flue Gas over CuO/Al_2O_3 Catalyst-Sorbents

摘要

CuO/Al_2O_3 catalyst-sorbents have received much attention for simultaneous removal of SO_2 and NOx from flue gases because that (ⅰ) it readily adsorbs SO_2 in the presence of O_2 to form CuSO_4 in a wide range of temperatures; (ⅱ) it is relatively easy to regenerate under reducing conditions; (ⅲ) copper compounds (CuO and CuSO_4) are catalytically active for selective reduction of NOx to N_2 with NH_3 as a reducing agent(SCR). Recently, Jeong et al. [4] reported that SO_2 removal capacity of CuO/Al_2O_3 catalyst-sorbents can be enhanced by addition of alkali salts. However, it was also reported that alkali salts deactivate the SCR activity of V_2O_5/TiO_2. Since the main limitation in use of CuO/Al_2O_3 in practice is the low sulfur removal capacity, the role of alkali salt in CuO/Al_2O_3 needs to be fully understood in order to formulate catalyst-sorbents of high sulfur removal capacity as well as high SCR activity. In the present work, the SCR of NO and simultaneous removal of SO_2 and NO using Na containing CuO/γ -Al_2O_3 catalyst-sorbents are studied in detail in a fixed-bed reactor.