| With the rapid development of China’s society and economy and the acceleration of industrialization,environmental pollution has become an unavoidable major problem,and environmental air pollution has become one of the environmental pollution problems that China urgently needs to solve.In recent years,more and more haze has affected people’s lives and health.Haze is mainly composed of a mixture of aerosols,sulfates,nitrates,organic hydrocarbons,etc.that are emitted into the atmosphere.Flue gas emitted from coal-fired power plants and steel mills in production contains large amounts of pollutants such as SO2,NOx,and particulate matter.Before the emission,the flue gas must be denitrified,dust-removed,and desulfurized.Limestone/gypsum wet desulfurization is the most commonly used desulfurization method,which can effectively control the concentration of pollutants in coal-fired exhaust gas and alleviate the current status of air pollution.The desulphurized flue gas carries a large amount of droplets and is discharged into the atmosphere.The droplets are naturally affected by the atmosphere,and the water evaporates and crystallizes out dust mainly consisting of respirable particles.Therefore,reducing the amount of entrained droplets when dealing with smoke also requires focus..At present,limestone/gypsum wet desulfurization is the most widely used desulfurization process.This paper uses this process as the research object,and tests the desulfurization tower slurry,the wet condensate and the chimney water in the desulfurization process,and calculates the desulfurization tower.Internal temperature pressure and droplet settling and escape.Comprehensive explanation of wet desulfurization smoke aerosol conversion and its characteristics.The main research results are as follows:(1)In this paper,the concentration of anions and cations in water samples was determined by ion chromatography and atomic absorption spectrometry to obtain the concentration ratios of soluble salts and ions between droplets entrained during the desulfurization of flue gas.The same absorption solution.(2)Calculate the temperature,partial pressure,and humidity during the desulfurization of flue gas at 110℃ and 280℃ for a desulfurization tower with a height of 10m.The results show that the temperature of the flue gas and the absorption liquid monotonically decreases with the height of the tower and is always the heat transfer from the flue gas to the absorption liquid.The gas and liquid partial pressure lines in the gas phase intersect at about 1 to 2 m,and the intersection divides the tower into upper and lower parts.:The lower partial vapor pressure is lower than the saturated vapor pressure,and water evaporation occurs.The upper vapor partial pressure is greater than the saturated vapor pressure,vapor condensation occurs,and the mass transfer direction changes.(3)Calculate the relationship between the velocity of smoke and the settling velocity of droplets and the amount of entrained droplets.The results show that too small droplets are quickly removed by the flue gas after being sprayed by the atomizer;slightly larger fog.The drop speed ut is slightly greater than the smoke speed,the drop is slow,and the residence time is long;too large droplets fall rapidly,and the dwell time is very short.Optimizing atomizer nozzle spray conditions and reducing the number of large droplets helps to increase the desulfurization efficiency.At the same time,a dust collector must be connected behind the desulfurization tower process to suppress the entrainment of the smoke droplets.(4)In the adsorption experiments,the salt sols produced by the gypsum method,ammonia method and fog evaporation of the power plant gypsum method under the darkness of 30 min dark,the toluene adsorption rate were 11.3%,15.5%and 12.5%.After 150 min light exposure,toluene was again reduced by 2.5%,1.9%,2.5%,respectively.It shows that the salt sol produced by the evaporation of droplets has obvious adsorption performance and shows a certain photoactivity under light conditions. |
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