Study On The Quantification Model Of Pollutants Emission Based On BAT-OOPN Method

With the rapid development of economic,the circumstance on the economic development and people's livelihood has been deteriorated with the emission of more pollutants.Therefore,the pollutants emission of typical industries should be supervised strictly to promote the optimization of purification craft and the improvement of environmental quality.So it is vital to enact the reasonable pollutants emission limits.The underlying problems on enacting pollutants emission limits by best available technology(BAT)are discussed from the perspective of methodology and system theory.And from the microscopic and macroscopic fields,enacting pollutants emission limits is proved to be nonlinear system and the production and discharge of pollutants is a random process,so it can be improved and perfected using complex system model and simulation theory,then the unification of flow diagram analysis,mass balance calculation and logical language judgment can be realized and the ability on data analysis and fault diagnosis can also be improved.Petri net is one of the methods of analyzing discrete event dynamic system with the function of drawing and calculating.The effective combination of Petri net theory and object-oriented technology could turn the process structure into icons,delaminate from top to down and simplify the complex issues.In this paper the mathematical models with calculation function are applied to the BAT,the pollutants emission limits of typical industries are made based on the OPMSE simulation platform and the BAT-OOPN methodology system is also constructed from the perspective of system theory.Firstly the Petri net theory and method are introduced to the modeling and simulation of power plant flue gas pollutants emission control process.And the Petri net model on the power plant flue gas treatment is built based on BAT to determine the contamination nodes and analyze the contamination factors.Then the quantification model of pollutants emission of papermaking and oil refining plants based BAT-OOPN is built and the concentration ranges of water pollutants are obtained by the statistical analysis of historic monitor data selected randomly from papermaking and oil refining plants' water pollutants(BOD5,COD and NH3-N),and the interval ranges of pollutants removal rates in each treatment process are also set.Then according to the production and discharge process of papermaking and oil refining plants,the simulated calculation of removal ability on BAT water pollutants treatment process is completed using the OPMSE software based on Petri net theory and the confidence intervals of each pollutant concentration after treatment are also acquired.The results indicate that when the treatment processes for the papermaking and oil refining plants operate normally and the confidence level of papermaking plant is 99%,the confidence intervals from the normal distribution of BOD5,COD and NH3-N are(34.04,41.77),(6.64,8.39)and(6.26,7.33),respectively;the optimal emission concentrations of BOD5,COD and NH3-N are 12.79mg/L,2.62mg/L and 3.33mg/L and the worse emission concentrations are 70.47mg/L,14.51mg/L and 10.22mg/L.In addition,when the confidence level of oil refining plant is 99%,the confidence intervals from the normal distribution of BOD5,COD and NH3-N are(51.85,54.88),(12.49,13.98)and(6.89,7.67),respectively;the optimal emission concentrations of BOD5,COD and NH3-N are 41.20mg/L,6.50mg/L and 5.10mg/L and the worse emission concentrations are 68.90mg/L,18.30mg/L and 9.90mg/L.According to the simulation results and the existing emission standards,the emission limits for papermaking and oil refining plants in Liaoning province are preliminarily set as 45mg/L of COD,9mg/L of BOD5,8mg/L of NH3-N and 55mg/L of COD,15mg/L of BOD5,8mg/L of NH3-N,which provides the guidance for enacting emission limits and reflects the practical significance for the quantification model of pollutants emission limits based on BAT-OOPN theory.Finally,the quantification model of pollutants emission of roasted molybdenum concentrate and suizhong power plant based BAT-OOPN are built by the combination of the object-oriented technology and Petri net and the concentration ranges of flue gas pollutants are obtained by the statistical analysis of historic monitor data selected randomly from typical enterprises' flue gas emission pollutants(particulate matter,sulfur dioxide,nitrogen oxides),and the interval ranges of pollutants removal rates in each treatment process are also set.And then according to the production and discharge process of typical enterprises,the simulated calculation of removal ability on BAT air pollutants treatment process is completed using the OPMSE software based on Petri net theory and the confidence intervals of each pollutant concentration after treatment are also acquired.The results indicate that when the purified treatment processes of roasted molybdenum concentrate operate normally and the confidence level is 99%,the confidence intervals from the normal distribution of dust and sulfur dioxide are(22.05,24.09)and(95.51,99.04).The optimal emission concentrations of dust and sulfur dioxide are 12.89mg/m3 and 79.29mg/m3 and the worse emission concentrations are 32.51mg/m3 and 114.86mg/m3.According to the simulation results and the existing emission standards,the ultra-low emission limits for roasted molybdenum concentrate industries in Liaoning province are set as 100mg/m3 of sulfur dioxide and 25mg/m3 of dust preliminarily.Besides,when the treatment processes of SCR denitration-bag dust cleaning-gypsum method desulfuration for the power plant operate normally and the confidence level is 99%,the confidence intervals from the normal distribution of Particulate matter,sulfur dioxide and nitrogen oxides are(4.0,4.9),(10.9,14.2),(35.1,39.1),respectively.The optimal emission concentrations of particulate matter,sulfur dioxide and nitrogen oxides are 1.7mg/m3,2.Omg/m3 and 19.8mg/m3 and the worse emission concentrations are 7.5mg/m,31.0mg/m3 and 47.9mg/m.According to the simulation results and the existing emission standards,the ultra-low emission limits for coal-fired power plants in Liaoning province are set as 5.0mg/m3 of particulate matter,15mg/m3 of sulfur dioxide and 40 mg/m3 of nitrogen oxides preliminarily.In addition,the historic monitor data on roasted molybdenum concentrate and thermal power industries' pollutants emission reveals that the concentration ranges in 99%confidence interval are lower than the emission limits mentioned above,which reflects the practical significance for the quantification model of pollutants emission limits based on BAT-OOPN theory.When the flue gas temperatures are among 325-345?,the denitrificaiton efficiency is highest after opitimization of SCR process by the BAT-OOPN model,which both meets the emission standard and saves the purification cost.The relative error of SO2 theoretical value in flue gas calculated by the BAT-OOPN model compared to SO2 measured value is lower 10%,which indicates the result is reasonable.In a word,the quantification model of pollutants emission limits based on BAT-OOPN theory for thermal power industries not only is able to supervise the enterprises' pollutants discharge but also is beneficial to the high-efficiency and low-cost operation of purification process.