Study On Optimization Of Structure Of Bag House Transformed From ESP Of Dust Removal System In Sintering Machine Tail

At present,dust collecting equipment of sintering machine tail is mainly electrostatic precipitator(ESP).However,the collection efficiency is low for fine particulate matter,as a result it is difficult to meet the new discharge standard,that is emission standard of air pollutants for sintering and pelletizing of iron and steel industry.Therefore,it is urgent to take some measures to reform the ESP.The most effective method is the bag house transformed from ESP.To solve the problems of uneasy replacement of filter bags during the dust collector operating,and uneven distribution of airflow in the traditional bag house transformed from ESP,two kinds bag house transformed from ESP was proposed in this paper based on different structures of ESP.One was new type bag house transformed from ESP that the gas inlet of every bag room was on both sides of the dust collector.The other was sectional bag house transformed from ESP.The gas flow was evenly allocated to every bag room,and the fact that filter bags can be replaced during the dust collector operating could come true.The numerical simulation on the flow field was carried out by CFX software.The simulation results indicated that new type bag house transformed from ESP has advantages that the gas flow in the every filter bag was basically identical,and the velocity distribution of gas flow under the filter bags was more uniform,and the deflective flow was not obvious compared with the traditional bag house transformed from ESP.Besides,the wear of the filter bag and the secondary dust was effectively controlled.The rate and victor of gas abruptly varied when gas flow entered bag rooms from flue in sectional bag house transformed from ESP,at the same time,the large particles was collected to middle ash hopper under the together function of gravity and inertia force,and the wear of filter bag was effectively slow down.The velocity near the bottom of filter bags was less than 5m/s,and the velocity in the inner of bilateral dust hopper was less than 6m/s,thus the wear of the filter bag and the secondary dust was effectively controlled.In addition,the long filter bag and pulse-jet cleaning system was adopted in order to make a better use of the inner space of ESP.The injection system was optimized according to the result of numerical simulation.The injection rate of the air into each bag was basically consistent after adjusting diameter distribution of the injection hole.The optimization measure that diameter of 20 mm hole was set on the nozzle was taken,which resulted that the pulse-jet gas flow was effectively increased.It had best effect when the number of holes was 2 or 3.Through monitoring and analyzing the properties of dust of sintering machine tail,polyester membrane filter media was advised to be used as the filter material of bag house transformed from ESP.Field application indicated that outlet dust concentration can be controlled less than 10 mg/m~3,and collection efficiency was more than 99.9%.So it could completely meet the requirement of dust removal in sintering machine tail.