Abstract: The V₂O₅-WO₃-MoO₃/TiO₂ honeycomb catalyst was prepared with industrial grade chemicals. The structural and physico-chemical properties were analyzed with X-ray diffraction (XRD), scanning electron micrograph (SEM) and mercury porosimetry. The NO_x conversion and durability were investigated on a pilot plant test set under the actual operational conditions of a coal fired boiler. The catalyst monolith had good formability with mass percentage of V:W:Mo:TiO₂:fiber glass 1: 4.5:4.5:72:18. Vanadium, tungsten and molybdenum species were highly dispersed on anatase TiO₂ without causing the transformation of anatase TiO₂ to rutile by calcining under a current of air at 450 °C for 4.5 h, but there were some degrees of crystal distortion. The catalyst particle sizes were almost uniform with close pile-up and the pore structure was regular with complete macro-pore formation and large specific surface area. The NO_x conversion was sensitive to temperature but nearly insensitive to NH₃. The catalyst showed strong adaptability to NO_x concentration with activity above 80% in the range of 615-1640 mg·m^-3. Within the range of 720-8640 h continuous operation, the NO_x conversion dropped at a rate of about 1% reduction per 600 h.

Key words: selective catalytic reduction, V₂O₅-WO₃-MoO₃/TiO₂ catalyst, physico-chemical property, flue gas, life time

摘要： The V₂O₅-WO₃-MoO₃/TiO₂ honeycomb catalyst was prepared with industrial grade chemicals. The structural and physico-chemical properties were analyzed with X-ray diffraction (XRD), scanning electron micrograph (SEM) and mercury porosimetry. The NO_x conversion and durability were investigated on a pilot plant test set under the actual operational conditions of a coal fired boiler. The catalyst monolith had good formability with mass percentage of V:W:Mo:TiO₂:fiber glass 1: 4.5:4.5:72:18. Vanadium, tungsten and molybdenum species were highly dispersed on anatase TiO₂ without causing the transformation of anatase TiO₂ to rutile by calcining under a current of air at 450 °C for 4.5 h, but there were some degrees of crystal distortion. The catalyst particle sizes were almost uniform with close pile-up and the pore structure was regular with complete macro-pore formation and large specific surface area. The NO_x conversion was sensitive to temperature but nearly insensitive to NH₃. The catalyst showed strong adaptability to NO_x concentration with activity above 80% in the range of 615-1640 mg·m^-3. Within the range of 720-8640 h continuous operation, the NO_x conversion dropped at a rate of about 1% reduction per 600 h.

关键词: selective catalytic reduction, V₂O₅-WO₃-MoO₃/TiO₂ catalyst, physico-chemical property, flue gas, life time