Process compatible desulfurization of new suspension preheater cement production: Rapid catalytic oxidation of trace SO2 over V2O5-based catalysts in preheater environment

Efficient capture of sulfur dioxide (SO2) in the preheater of the cement production system is the key to achieving process compatible flue gas desulfurization (FGD). Herein, the rapid oxidation of trace SO2 over V2O5-based catalysts in the preheater environment was realized to enhance the SO2 capture capacity of limestone in raw meal, and the catalytic efficiency was further improved by 45.2%, 56.1% and 61.9% after introducing TiO2/MnO2/CeO2 as cocatalysts, respectively. The V2O5-based catalysts had superior catalytic behavior only when the flue gas temperature exceeded 500 °C, while the composition variation of flue gas had a minor influence on SO2 oxidation. Finally, a maximum SO2 oxidation efficiency of 68.1% was achieved in the presence of 4.0% O2, 25.0% CO2 and 15.0% H2O at 600 °C. Furthermore, the mechanism of SO2 catalytic oxidation over V2O5-based catalysts was deduced based on the results of XRD, BET, XPS and Raman, and V5+ was identified as the primary vanadium species for SO2 oxidation. The results provide a deeper insight into the catalytic oxidation of SO2 in the preheater environment, and then facilitate the improvement of process compatible FGD and available dry FGD technologies for cement industry.