Abatement of Fine Particle Emission by Heterogeneous Vapor Condensation During Wet Limestone-Gypsum Flue Gas Desulfurization

摘要

The fine particles in desulfurized flue gas comprise coal-fired fine particles from combustion and generated fine particles from desulfurization. The abatement of fine particle emission by heterogeneous vapor condensation during wet flue gas desulfurization (WFGD) is experimentally investigated in this paper. A supersaturation atmosphere, which is necessary for heterogeneous vapor condensation, is established by increasing the humidity and reducing the temperature of the flue gas before WFGD. The improvement of the removal of coal-fired fine particles and the inhibition of generated fine particles formation in desulfurization process by heterogeneous vapor condensation were studied, and the influences of inlet flue gas parameters on the emission of total fine particles, including coal-fired fine particles and generated fine particles during desulfurization, are examined. The results indicate that the total emission of fine particles in desulfurized flue gas can be significantly decreased via heterogeneous vapor condensation. This decrease in the emission of coal-fired fine particles is mainly related to the removal of fine particles via heterogeneous vapor condensation, and the generation of fine particles from desulfurization is abated because of both the decrease in the inlet flue gas temperature and heterogeneous vapor condensation. Higher inlet flue gas humidity can adequately reduce the emission of generated fine particles from desulfurization. The reduction in the flue gas temperature before WFGD is the main factor that inhibits the formation of fine particles and removes coal-fired fine particles during desulfurization.