Study On Atmospheric Pollutants Emission Characteristics And Mitigation Potential Of Aluminum Industrial Furnace In Zhengzhou City

This paper takes three types of aluminum industrial furnaces in Zhengzhou including?-alumina,Bayer process alumina and electrolytic aluminum as research object.The dilution channel sampling method was used to collect PM_2.5 and PM₁₀samples in the furnace flue gas.The mass concentrations of SO₂ and NO_x were detected by a flue gas analyzer.Water-soluble ions,carbon components and heavy metal element components in PM_2.5 and PM₁₀ were analyzed,and corresponding source profiles were established.The differences of mass concentration,chemical composition profiles,characteristic ratio and emission factors between three types of aluminum industrial furnaces were researched.the use of obtained localized emission factors,the aluminum industrial furnace main pollutant emission inventory of Zhengzhou in 2017 was established.the scenario analysis method was used to analyze the emission reduction potential of atmospheric pollutants emitted by three types of aluminum industry furnaces for Zhengzhou City in 2020.The main conclusions of this paper are as follows:The highest concentration components of PM_2.5 and PM₁₀ from?-alumina,Bayer process alumina and electrolytic aluminum furnaces were respectively Cl^-,OC and EC,and the concentration of organic carbon?OC?in the fine particles of three types of furnace were both higher.According to the anion and cation ratio of fine particles?C/A?,PM_2.5 emitted by?-alumina was acidic and PM₁₀ was close to neutral.PM_2.5 and PM₁₀emitted by Bayer process alumina and electrolytic aluminum were all alkaline.The OC/EC ratio in the fine particles of the three types of aluminum industrial furnaces showed a trend of?-alumina>Bayer process alumina>electrolytic aluminum.We should be alert to the risk of secondary pollution of fine particles in the above order.The chemical components with the highest proportion in the fine particle source profiles of?-alumina,Bayer process alumina and electrolytic aluminum were respectively Cl^-,OC and EC.The coefficients of divergence?CD?showed that the source profiles of particles with different particle size emitted by the same production process were similar,and the source profiles of particles with the same particle size from the three types of furnaces were different greatly.According to the component difference weight distribution function|R/U|values,EC,Ca,F^-and Cl^-could be used as the identified components to distinguish the two alumina production processes.EC,Al,Cl^-and NH₄⁺could be used to distinguish?-alumina and electrolytic aluminum production processes.OC,Fe,and Si could be used as identified components to distinguish Bayer process alumina and electrolytic aluminum production processes.This paper also calculated the emission factors of the main pollutants for the three types of aluminum industrial furnaces.Among the pollutants emitted by the three types of aluminum industrial furnaces in Zhengzhou,2017,the emissions of NO_x were the largest,and the largest emissions of the three types of chemical components in the fine particulates were EC,NH₄⁺and Cu.The electrolytic aluminum industry had the largest contribution to the emissions of PM_2.5,PM₁₀ and SO₂.The Bayer process alumina industry had the largest contribution to NO_x emissions.The?-alumina industry had the highest emissions of F^-and Cl^-in fine particles.The PM_2.5,PM₁₀,and SO₂ emissions from the three types of aluminum industrial furnaces in Gongyi City were much higher than those in other regions.The NO_x emissions in Shangjie District were the highest in all Zhengzhou City.There are also a large of emissions for some crust elements and carbon components in Dengfeng region.Scenario analysis showed that the emissions of SO₂ and NO_x emitted by three types of aluminum industry still had great emission reduction potential in Zhengzhou.The emission reduction rates of SO₂ in 2020 under the best applicable scenario?BAS?and highly efficient control scenario?HECS?were respectively 34.5%?47.1%and78.6%?82.6%.The emission reduction rates of NO_x in the best applicable scenario?BAS?and highly efficient control scenario?HECS?in 2020 were 19.8%?29.8%and48.1%?50.7%.The reduction of two types of the above pollutants could be achieved by increasing the coverage and the efficiency of pollutant control measures.