Research On Dedusting Characteristics Of Tobacco Redrying Plant

China’s tobacco industry ranks in the forefront of the world,with a large number of workers engaged in tobacco production,and the redrying plant is a major link in cigarette production.In the whole process of tobacco redrying,productive dust(tobacco dust)is an occupational health hazard that cannot be ignored.If it is not controlled,it will have a great impact on the occupational health of workers.At present,although tobacco redrying enterprises have set up dedusting facilities,the dedusting design of exhaust hood based on economic,reasonable and efficient has not attracted attention and in-depth exploration.Therefore,the study on the dedusting characteristics of the exhaust hood in the blade laying and swinging section has a good practical significance.Starting from the practical application,this paper takes the wind speed at the control point of tobacco dust source as the measurement standard,and takes the dust under different working conditions such as exhaust hood height and exhaust duct wind speed as the research object to explore and study the air flow and tobacco dust concentration.Through the field investigation and data review of tobacco redrying enterprises,the dust in the leaf spreading and swinging section was collected and tested to determine the dust source concentration,tobacco dust density,particle size and other relevant parameters.The physical model is established according to the geometric model of the actual situation of the blade laying pendulum section,and the control equation of the numerical theoretical model is determined.By using FLUENT in ANSYS to simulate the working conditions such as different exhaust hood heights,different exhaust duct wind speeds,and whether exhaust hood baffles are available,the distribution law of tobacco dust concentration under different working conditions,the characteristics of airflow movement,and the wind speed at the control point of the dust source are analyzed,and the change trend of the wind speed at the control point under different conditions is obtained.Then,the wind speed of control points under different working conditions is modeled and analyzed through multiple regression,and the best dust removal effect and economic and reasonable dust removal design are obtained.Through the analysis of simulation modeling results,it can be seen that the air volume,i.e.the air velocity at the nozzle of the exhaust pipe,can affect the air velocity at the control point.When the height of the exhaust hood from the operating platform is 0.6m,the air velocity at the control point generally increases first and then stabilizes with the increase of the air velocity at the nozzle,and the trend is gentle and stable at 0.52m/s;The height of the exhaust hood will have a significant impact on the wind speed at the tobacco dust control point.When the wind speed at the exhaust pipe nozzle is 50 m/s,the wind speed at the control point increases first and then decreases with the increase of the exhaust hood height,and the maximum wind speed at the control point is 0.512 m/s;The baffle of the exhaust hood is conducive to the discharge of tobacco dust.With the increase of the wind speed at the exhaust pipe nozzle after the baffle is added,the wind speed at the control point where the baffle is added on both sides of the exhaust hood increases significantly more than that without the baffle,and the upper limit of the stable wind speed increases significantly,and the wind speed at the control point reaches 0.810m/s.When the wind speed of the exhaust pipe is between 0 m/s-100 m/s,0.46 m is the minimum height from the exhaust hood to the operating platform that meets the dust removal requirements in the leaf spreading and handle releasing section of the tobacco redrying enterprise.The height of the exhaust hood from the operating platform is 0.6m,the length of the exhaust hood baffle is 0.3m,and the wind speed at the exhaust pipe nozzle is 15.24m/s.It is the most economical and reasonable dust removal design for the tobacco redrying enterprise’s leaf laying and swinging section.The wind speed at the control point is 0.5m/s,which can meet the minimum dust removal requirements.