Research On Layer Burning Industrial Boiler PM_2.5 Emissions Characteristics

The annual coal consumption of China’s industrial furnaces is about400million tons. The coal combustion generated600million tons of CO2,5⁶milliontons of SO2,8million tons of soot and87million tons of ash each year. Amongwhich, the fine particles of PM_2.5pollution has blocked China’s improvement ofenvironmental quality.Therefore,to improve the atmosphere environment and Chin-a’s energy and environment sustainable development, it is of great significance toundertake the research of the fine particles PM_2.5emission characteristics ofcoal-fired industrial furnaces and the study on energy conservation and emissionreduction.In this regard, this paper chose three typical coal-fired industrial furnaces inHarbin during2011²012collecting PM_2.5samples, using high resolution SEM,ELPI on-line continuous test and IC, ICP-OES, thermo-optic method and otherappropriate sample element analysis method to research and analyze the coal-firedindustrial furnaces of fine particles PM_2.5emission property, and obtained thefollowing results:The result of particle size distribution shows that, when the particle-numberconcentration of fine particles of PM_2.5is106¹07cm-3, it demonstrated a unimodalmode in the measured particle size distribution, and the peak appeared in the rangeof0.07⁰.2μm.This group of the particles if formated by the gasification conden-sation mechanism. The mass concentration also revealed a unimodal distribution.When the peak appears within the range of0.12⁰.32μm, comparing to particlenumber concentration peak, the mass concentration peak will move towards the sideof the larger particle size. For less than0.1μm particles, the removal efficiency ofthe dust remover is relatively high. For larger than1μm particles, as the particle sizeincreases, the removal efficiency increases. As for the0.1¹μm particles, theremoval efficiency is minimum. In addition, for the industrial furnaces simplifiedwet desulfurization process system, there is need to choose the demister with goodperformance in order to avoid the spraying tower Droplets spillover to form a largeamount of PM_2.5particles, thereby reducing the emission of PM_2.5. The results of the study on chemical composition shows that, among the PM_2.5discharged by industrial furnaces, SO42-is the most abundant water-soluble ionswhose composition percentage fluctuates in the range of3.9%³.97%.Single particle morphology and mineral composition of research results showthat, from of the industrial boiler emission PM_2.5can be divided into four categories:spherical particles（spherical, more tiny particles attached to the surface of thesphere）, irregular particles（solid structure, chip structure）, soot aggregates （chain,chain compressed together dough） and superfine particles. Industrial boileremissions of PM_2.5aluminum as the principal ingredient of silicon oxide, whichcontains a small amount of aluminum oxide, iron oxide. In addition, the unburnedcoal is the main component of carbon, while PM_2.5content is less, is a typical typeof PM_2.5particles.