Study On Emission Characteristics Of Ultrafine Particle From Coal Combustion

China is a big county of energy consumption, and at present, coal is themain fuel in the energy consumption structure. Millions of particles generated fromcoal combustion have causing serious air pollution in many cities in China. Therefore,it has aroused a world-wide attention to study on the formation, transmission andcontroll of ultrafine particles.In this paper, the FMPSTM(Fast Mobility Particle Sizer) spectrometer was usedfor measuring particle size spectrum, number and mass concentrations of aerosolswhich generated from pulverized coal combustion. Based on the emissioncharacteristics of coal combustion, the particles transporting and dynamic evolutionwere studied.The evolution law of particle size spectrum was analyzed through pulverizedcoal combustion experiments under laboratory conditions. The results showed that atthe beginning of the particle generated, the particle size spectra generated frompulverized coal combustion were polydisperse and complex, the initial size spectrawere mainly composed of three modes including10nm,30nm-40nm and100nm-200nm. Among them, the number concentration of mode around10nm was higherthan other modes, the size spectrum around100nm-200nm was lognormaldistributed, with the CMD (Count Median Diameter) around16nm and MMD (MassMedian Diameter) around200nm. As time went on, total number concentrationswere decayed by exponential law, the CMD and MMD were increased first thentended to be stable gradually. With the decreased of particle size, particle decay rateshad increasing trend. The particle mass spectra were more concentrated in the rangeof100nm-400nm, which is logarithmic normal distribution and the decay processof mass concentrations were firstly increased and then decreased.The particle dynamic evolution model was set up, through compared the modelcalculation results with the experimental data, the model calculation values could beable to better fit with the experimental data, and predict size spectrum evolution ofaerosols, the attenuation of total concentrations. Coagulation and sedimentation played an important role in the process of particle spectrum evolution, the calculationresults showed that ignoring the coagulation would lead to calculate the particlenumber concentration on the high side, and ignoring the coagulation growth wouldlead to underestimate number concentration, ignore the deposition can makeestimates of particle concentration on the high side, especially the numberconcentrations of ultrafine particles.The emission factor of ultrafine particles from coal combustion under laboratoryconditions was calculated based on the model. The results showed that the emissionfactor of ultrafine particles from coal combustion was (5.54±2.18)×1012unit·g-1.