Investigation of sulphated CuCl2/TiO2 catalyst for simultaneous removal of Hg0 and NO in SCR process

Abstract

To achieve the oxidation of mercury in the presence of HCl with low concentration and mitigate the inhibition effect of NH3, sulphated CuCl2/TiO2 catalyst was investigated for simultaneous removal of Hg0 and NO in SCR process. The sulphation was conducted by exposing CuCl2/TiO2 catalyst to a gas stream containing SO2 and O2.Characterizations of catalysts (BET, XRD, XRF, XPS, TG-MS and NH3-TPD) were carried out to illuminate the structure-performance relationship. Results showed that the remained CuCl2 and generated CuSO4 over this catalyst were responsible for Hg0 oxidation and NH3-SCR reaction. The generated CuSO4 increased the amount of acid sites on catalyst surface thus promoting the SCR activity. CuCl2(S18)/TiO2 catalyst exhibited simultaneous catalytic oxidation of Hg0 (around 73.9%) and NO (around 87%) at the temperature of 325 °C. Hg0 oxidation over this catalyst was not handicapped by the low content of HCl in gas stream, different from commercial SCR catalyst. Individual NO and NH3 showed insignificant effect on Hg0 oxidation. While the co-presence of NO and NH3 somewhat inhibited it. Moreover, good resistance to the moderate concentration of SO2 and H2O for the catalyst was observed.