| Shanxi Province as a region with a relatively abundant coalresources, the pollution to the environment is well known. And SO2derived from Coal-fired Power Plants has a significant impact on theatmospheric environment by transportation and transformation. In orderto control SO2from the sources，it needs to analyze the impact onatmospheric pollution and the surrounding environment of the SO2emission from the power plant at present. ADMS model couples the latestprogress in the study of the atmospheric boundary layer, uses the routinemeteorological elements to define the boundary layer structure. Due tothe practicality and high precision, it is widely used in regional airpollutant diffusion simulation. So simulating and forecasting the SO2emissions of the coal-fired power plants and discussing the rules of theSO2emissions with ADMS model has great significance to improve thelocal atmospheric environment. On the basis of the pollution emissions data in the year of2013, theSO2emission lists are obtained. Through the ADMS model, Surfersoftware and other tools, the transfer process of SO2from the power plantis simulated. Then combining with the actual monitoring results, the SO2concentration, SO2-4concentration and their total deposition, drydeposition, wet deposition around the power plant are analyzed. The mainconclusions are as follows:（1）The influence of meteorological conditions on the diffusion ofSO2concentration distributionSO2concentration varies with the temperature, because there isinversionin the night,and it is not easy to the diffusion of pollutants. Sothe concentration increases. During the day, the inversion layerdisappears, pollutant diffusion increases, and therefore the concentrationdeclines. In the evening, ground temperature gradually decreases,inversion layer forms again. Such phenomenon repeates continually,which causes the pollutants concentration distribution of "V".The wind speed of night is small, and the wind direction of night isrelatively single, they all are disadvantageous to the pollutant diffusion.Butduring the day,the wind speed is larger, the wind direction isrelatively complex, pollutant concentration is relatively low in differentdirections and in a broader. The wind has a great influence of diffusion effect to the pollutants, the pollutant concentration is high under thedownwind of pollution source.Amount of cloud cover has a inhibitory effect on the diffusion ofpollutants. When the amount of cloud cover is twenty percent，the SO2concentration of each point of the axis is high. So the higher the cloudcover, the higher the concentration of the pollutants.Flushing action of the rain to SO2is very strong.When the rainfall is2.1mm, the SO2concentration of each point of the axis is high. So thegreater the rainfall, the lower the concentration of the pollutants.(2)The time distribution features of SO2concentration diffusionAverage value of SO2maximum hours concentration is in "V" shapedistribution. It is low during the day and high in the evening. It is higherfrom18PM to7AM.From8AM, it begins to decline, and reaches thelowest at16PM, and then begains to rise from the17PM. This is mainlydue to the temperature change caused by the cycle of day and night in aday.The distribution of the biggest daily average concentration of SO2changes in peak shape, this is because the meteorological conditionschange day and night, their ups and downs is big. So it has not obviousregularity. For the change of seasons, the concentration of spring and winter is higher than that of summer and autumn. The meteorological conditions have relationship with the change of seasons. Atmospheric diffusion conditions of summer and autumn is making for the diffusion of SO2, and the atmospheric diffusion conditions of spring and winter is go against the diffusion of SO2.(3)The spatial distribution characteristic of SO2、SO42-concentration and their depositionSO2concentration distribution is consistent with the direction of the wind on the whole, high concentration zone locates in NW-SE direction. The SO2concentration increases gradually outward from the source, and reach the maximumin about2-3km from the source, then decreases gradually. High value area of SO2and SO42-concentration distribution is consistent, emission source has a great influence to SO2and SO42-concentration distribution. But SO42-diffusion range is bigger than that of SO2.On the basis of the sulfur deposition distribution data, the total deposition amount is43.1215μg·m-2·s-1, dry deposition amount is37.7640μg·m-2·s-1, wet deposition amount is5.3575μg·m-2·s-1. Due to the less annual rainfall, dry deposition is the main form of total sulfur deposition, accounts for87%, and the distribution of pollution sources has a good correlation. And wet deposition accounts for87%, has a directrelationship with rainfall. The total settlement distribution has thecharacteristics of the combination of dry deposition and wet deposition.（4）The seasonal distribution characteristic of SO2-2、SO4concentrationand their depositionIn general, the SO2-2and SO4highest concentration of each seasonon the area distributes in the NW-SE, but the concentration range isslightly different in each season, summer is the most light, next autumn,winter and spring is most serious. This is associated with themeteorological conditions of the year. The diffusion conditions ofsummer and autumn is good, it is easy to pollutants spread andtransmission over a long distance, while the diffusion conditions of springand winter is bad to transport, diffusion of pollutants.The total SO2deposition amount of different season varies obviously.The total SO2deposition amount of winter is largest, then total SO2deposition amount of spring is second, the total SO2deposition amount ofautumn is third, and that of summer is the least. According to themeteorological data, the precipitation of spring and winter is close to zero,so the wet deposition amount is near to zero too. Because the rainfall canwash more SO2-4in the summer than that in autumn, the wet depositionamount of the summer is more than than of autumn. |
PDF Full Text Request