Study On PM2.5Emission Characteristics And Pollution Control From Coal-fired Power Plant

With the rapid development of Chinese economy, the haze enveloped at most ofthe country recently. The emissions of fine particulate matter PM2.5, which includessulfur dioxide, nitrogen oxides and volatile organic compounds and so on, have asubstantial increase. The zone of contamination spread from the most serious ofBeijing, Tianjin and Hebei to the coastal areas, which severely affected the travel andhealth of people. As one of the main source of PM2.5emissions from coal-firedpower plants, it is essential to understand the emission characteristics and to takepractical control measures.In this topic, we have analyses on the emissions concentration, size distributionand chemical and physical characteristics of PM2.5in flue gas particulates atupstream and downstream of the precipitator and downstream of desulfurization fromthree coal-fired boilers and one circulating fluidized boiler (CFB). The numberconcentration of PM2.5after desulfurization is about105/cm3, and the massconcentration of PM2.5is about0.57mg/m3, but some large is about19.3mg/m3. Thenumber concentration of PM2.5at upstream and downstream of the precipitator fromcoal-fired boilers in power plants shows a dual-normal distribution, and the peaks arearound0.76μm and0.12μm; the number concentration distributes in0.01~0.1μm, andthe mass concentration distributes in the range of0.8~2.0μm. Precipitator efficiency:Electrostatic-fabric Integrated Precipitator and Bag Filer are better than ESP. Theemissions of PM2.5after desulfurization is not ideal, sometimes not decrease evenfall. The single particle morphology of research shows that, from of the coal-firedboiler emission PM2.5can be divided into two categories: spherical particles (regularshape and smooth surface) and irregular (solid and chip structure); while the particlemorphology of CFB PM2.5shows irregular particles. The proportion of Hg, Se, As, Vand Zn from coal-fired power plants emissions PM2.5is larger, thereby doing harm tothe environment and human health.We improve proposed methods to electrostatic precipitators from the presentcoal-fired power plant: a. changing charge form to adsorbing more fine particles; b.additional pretreatment device before ESP; c. proposing electrostatic-fabric integratedprecipitator, which change bag filter from three four farms of ESP and control thecleaning method and frequency depending on the operating conditions of Bag Filter.d. electric and bag staggered (AHPC), set up electrostatic-fabric integrated precipitator; e. After WFGD, installing wet electrostatic precipitator. Saturating theflue gas of WFGD, we could utilize steam phase change principles to increase PM2.5,which is made easier to capture, and install WESP at WFGD downstream to controlthe emissions PM2.5.