Generation and Emission Characteristics of Fine Particles Generated by Power Plant Circulating Fluidized Bed Boiler

Abstract

The generation and emission characteristics of fine particulates (PM2.5) from three 300 MW power plant circulating fluidized bed boilers were investigated. One boiler had an external bed and used an electrostatic precipitator, the other two used an electrostatic filter precipitator and fabric filter, respectively. The particle size distribution of fine particles was performed by an electrical low-pressure impactor. PM2.5 samplers were used at the same time to collect fine particles for subsequent laboratory analysis. The results show that the number size distributions of fine particles presented one single peak, but there was no peak in mass size distributions. The mass concentrations of three CFB boilers were similar, but the number concentration of the external bed CFB boiler was much higher than that of the general CFB boiler. The minimum removal efficiencies of the precipitator appeared between 0.1~1 μm, but the locations of the minimum point were different. The morphology of fine particles was mostly irregular. The highest content of fine particles was insoluble oxides and the content of S element was also high. Different precipitators have different removal effects on Si, Al, Ca, S and Fe in fine particles, but they all have poor removal effects on Na and K as well as OC and EC.