Research on the middle-low temperature denitration and anti-poisoning properties of plate V₂O₅-MoO₃/TiO₂ SCR catalysts

Considering the technical requirements for middle-low temperature denitration of flue gas, a series of powder and plate type V₂O₅-MoO₃/TiO₂ SCR catalysts were prepared using incipient wetness impregnation method with V₂O₅ as the active component and with MoO₃ as the promoter. Experiments were performed to investigate the effects of active component and promoter contents of the catalysts on the activities and the resistance to deactivation by SO₂ and H₂O. The characterization of the fresh and used catalysts was conducted, and the optimal catalyst was further studied to reveal the denitration performance under different flue gas conditions. The results indicate that the activities of the catalysts are enhanced with the increase of V₂O₅ loadings. Also, the addition of MoO₃ can promote the catalytic activity. The characterization results from XRF, XPS, FT-IR and other analysis suggest that the MoO₃ content could affect the V⁴⁺/V⁵⁺ ratio in the catalyst. The increase in relative MoO₃ content is favorable for the formation of non-stoichiometry vanadium species as well as the rise of chemical adsorption oxygen. Therefore, the interactions between molybdenum and vanadium species might be an essential reason for the resistance to the deactivation by SO₂ and H₂O. The denitrification efficiency of 3V₂O₅-10MoO₃/TiO₂ plate catalyst keeps steady around 82% after 30 days test in the presence of SO₂ and H₂O at temperature of 200℃ and space velocity of 3 500 h^-1. The catalyst is identified to have an excellent resistance to the deactivation by SO₂ and H₂O under middle-low temperatures.