Selective catalytic reduction (SCR) technology is usually used in coal combustion power plant to reduce NOx emission. The effects of SCR DeNOx on PM emission are still unclear. In this work

PM and fly ash before and after SCR was sampled. Particle size distribution (PSD) and chemical composition of PM was analyzed. Computer-controlled scanning electron microscope (CCSEM) was used to analyze the fly ash and obtain the composition distribution property of individual PM particles. The effect of SCR DeNOx on PM emission characteristic and its mechanism was investigated. The results show that PM is bimodal distribution before and after SCR. After the flue gas flows through the SCR

PM0.21 decreases 62%(mass) and PM0.21-1 increases 19%(mass). The relative amount of SO2 in PM1 increases 6%(mass) and SiO2 and Al2O3 decrease

while the variation of CaO is insignificant after SCR. The amount of PM1-10 decreases 17%(mass) after SCR. Insignificant change of its chemical composition is observed after SCR. However

the chemical composition distribution of individual PM1-10 particle becomes more homogeneous after SCR. It suggests that significant interaction between PM10 has happened in or after SCR. Therefore

decrease of PM1-10 after SCR is not only because of PM10 deposition in the SCR

but also because of particle interaction.