Effect of Selective Catalytic Reduction System on Fine Particle Emission Characteristics

Based on commercial catalysts (V2O5–WO3/TiO2), the effects of a selective catalytic reduction (SCR) system on the emission characteristics of fine particles were investigated. The size distribution, morphology, element compositions, and chemical compositions of fine particles at the outlet of the SCR system were measured by an electrical low pressure impactor (ELPI), particulate matter (PM10/PM2.5) samplers, field emission scanning electron microscopy/energy dispersive spectrometry (FSEM–EDS), X-ray diffraction (XRD), etc. The influences of reaction conditions and flue gas components on fine particle formation were also studied. The results reveal that a large number of fine particles can be generated during the SCR process. These fine particles are mostly in the submicrometer size range and appear to be nonuniform. The main components of these fine particles are ammonium sulfate or ammonium bisulfate. There is a good correlation between the formation of fine particles and the SO2 oxidation rate. Fine par...