Diffusion And Control Technology Of Electroplating Exhaust Gas

With the continuous improvement of my country's social economy,the electroplating industry is developing very rapidly.However,electroplating is one of the three most polluting industries in the world.The industrial tank solution in the electroplating workshop is subject to temperature,chemical reaction,air agitation,bubble entrainment,and its own properties,resulting in a large amount of acid mist,alkali mist,chromium-containing gas,and nitrogen oxidation.Waste gas from electroplating such as chemical substances,hydrogen cyanide,etc.,have a huge impact on the human body,equipment and the environment.Working in the electroplating workshop without ventilation measures for a long time,the workers are very likely to suffer from occupational diseases,and even die.In order to reduce the concentration of electroplating waste gas in the workshop and reduce the harm of the waste gas to the human body,it is necessary to conduct research on the diffusion law of electroplating waste gas and its control.In this study,the common sulfuric acid mist in the electroplating workshop was used as the research object,and the interior of the electroplating workshop was inspected and measured on-site,and the occupational hazards in the electroplating workshop were studied.According to the actual size of the electroplating workshop,ICEM software was used to establish a simplified physical model,and the control equation based on fluid mechanics was determined;compared with different calculation methods of ventilation systems,the flow ratio method proposed by Lin Taro was finally selected for air volume calculation.Using CFD simulation technology to simulate the free diffusion and ventilation of acid mist,and design orthogonal experiments for parameter optimization,the main conclusions are as follows:(1)The free diffusion of acid mist is mainly concentrated in the middle and lower parts of the electroplating workshop,around the exhaust hood and the wall.(2)Without external ventilation,the average mass fraction of acid mist in the human respiratory area of the horizontal control surface reaches 1.8×10^-3(2320.2 mg/m³).(3)Apply external ventilation and compare different factors(number of exhaust hoods,flange length,expansion angle,exhaust air volume,duct length,etc.)through the controlled variable method.The simulation results show that one exhaust hood controls acid mist The effect is better than multiple exhaust hoods;the control effect of the exhaust hood with flange edge is better than that of the exhaust hood without flange;the control effect of the expansion angle?is from large to small:60°>45°>30°;The greater the air volume,the better the capture effect of acid mist.It is concluded that a single hood,a flange of 0.5 m,an expansion angle of60°,and an exhaust air volume of 66560 m³/h are the best combination in the single-factor simulation.(4)Through the range analysis of the orthogonal experiment,the degree of influence of each factor on the indoor airflow organization is obtained:exhaust air volume>number of exhaust hoods>expansion angle>flange edge,and the range analysis result is verified by the variance analysis,and obtained The optimal combination is consistent with the range analysis,and it is finally determined that the optimal combination of the exhaust hood for this workshop is a single hood,with an air volume of 70,000 m³/h,an expansion angle of 60°,and a flange edge of 0.2 m.(5)When the optimal combination simulation of orthogonal test is 982 seconds,the concentration of acid mist in the control surface is reduced to below the national emission limit.Compared with the data provided by the enterprise,the partial collection efficiency reaches97.86%.