Study Of SCR Catalyst For Coal-fired Flue Gas Denitrification Grafted On Nanometer Titania

Selective catalytic reduction (SCR) is an important technology for denitrification of flue gas from coal-fired power plant, among which catalyst is the key elment of the whole DeNOx system.In this dissertation, with the help of a domestic manufacturer of nanometer titanium dioxide (TiO₂),SCR catalyst for coal-fired flue gas denitrificaiton was investigated systematically grafted on the domestic nanometer TiO₂. The whole dissertation includes the selection and optimization of the ingredient, geometry, preparation, operation conditions and kinetics of SCR catalyst in the form of powder and ceramic monolith by means of activity measurements and micro- and macro- characterization technologies such as BET, XRD, SEM-EDX, FT-IR, DTG and so on. By thorough investigation, it is found that 1%V₂O₅-10%WO3/ TiO₂ catalyst powder based on nanometer anatase TiO₂ form TiOSO4, which includs 8-10% sulfate (cal. SO₃ ) in the mass, is suitable for the preparation of monolithic SCR catalyst for coal-fired flue gas denitrification by mixing of proper kind and content of water, organic binder, extruding-aid addictive, pore-enlarging addictive, lubricating oil and fiber-glass in the sequences of mixing, kneading, extruding, drying and calcination under suitable conditions. Kinetic parameter of selected SCR catalyst powder was obtained, and then a global mathematical model including kinetics and intra-phase and intra-particle transfer was developed, which can be used for the design and performance of SCR catalyst.1. Among commercial anantase TiO₂, anatase and rutile nanometer TiO₂ from TiOSO4 ,TiCl4 and mixture of anatase and rutile nanometer TiO₂, anatase nanometer TiO₂ including 8-10% sulfate form TiOSO4, are proper as SCR catalyst support while anatase nanometer TiO₂ form TiCl4 are not suitable due to its reaction with V₂O₅ to form V₃Ti₆O₁₇.2. Ingredient optimization study of SCR catalyst by DeNOx activity and characterization technologies shows 1%V₂O₅-10%WO3/TiO₂-9.2%SO₃ catalyst, whose nano-grade support is made from TiOSO4, has large BET area and textile construction, high DeNOx efficiency, broad window temperature and good selectivity, whose performance is even superior to commercial catalyst in some areas.3. Kinetic parameter of selected SCR catalyst powder was obtained, and then a global mathematical model including kinetics and intra-phase and intra-particle transfer was developed, which can be used for the design and performance of SCR catalyst.