Simultaneous absorption of NOx and SO 2 in oxidant‐enhanced limestone slurry

In this article, a study of simultaneous absorption kinetics of NOx and SO 2 in oxidant‐enhanced limestone slurry using sodium chlorite as additives is presented. The laboratory‐scale experiments were performed in a double‐stirred tank reactor, and the effect of inorganic ions and operating parameters on absorption rates was investigated. The results indicate that NOx absorption rate shows a positive order with respect to NO (0.573), SO 2 (0.278), and NaClO 2 (0.194), whereas SO 2 absorption rate shows a first order with respect to SO 2 and zero order for both NO and NaClO 2 under a typical limestone wet flue gas desulfurization operating condition. Higher pH leads to a decrease of NOx absorption rate but has no significant influence on SO 2 absorption. The SO 2 absorption rate decreases with the increase of temperature, whereas the NOx absorption rate remains nearly constant. S(IV) in the slurry reduces the NOx absorption rate dramatically and suppresses the SO 2 absorption, whereas the presence of nitrate ions can increase the absorption rate of both SO 2 and NOx. High concentration of Cl − has a positive effect on the SO 2 absorption, whereas it has a negative effect on NOx absorption rate. Additionally, Mg 2+ and F − have no impact on SO 2 and NOx absorption rates. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1171–1179, 2014