Characteristics and composition of particulate matter from coal-fired power plants

Measurements of the characteristics of particulate matter (PM) were performed at the inlet and outlet of the electrostatic precipitators (ESP) of four boilers in two full-scale pulverized coal power plants. PM was collected with a 13-stages low-pressure-impactor (LPI) having aerodynamic cut-off diameter ranging from 10.0 to 0.03 μm for a size-segregated collection. The properties of PM including its concentration, mass size distribution, emission characteristics, percent penetration of PM through ESP and elemental composition were investigated. The experimental results indicate that, in all the cases the mass size distribution of PM₁₀ had typical bimodal. PM₁ contained up to 1.15 wt% of the total particle (TP) generated in the boilers. PM_2.5 contained about 2 wt%–7 wt% of the TP and PM₁₀ contained about 4 wt%–19 wt% of the TP. When additive limestone used for desulphurization as sorbent besides PM generated from coal combustion, there was new PM generated from limestone. Penetration as a function of particle diameter had a clear peak in particle size ranging from 0.2 to 0.6 μm. Particles in the submicrometer size range were much more difficult to be collected with ESP than larger particles. Distributions of individual elements within PM₁₀ were different. Supported by the National Natural Science Foundation of China (Grant Nos. 50720145604, 50721005, 90610017), the Programme of Introducing Talents of Discipline to Universities of China (“111” Project) (Grant No. B06019)