Study On The Process And Performance Of Flue Gas Dust Filter Based On High-speed Carding And Laying Web

The rapid development of China’s economy has led to a large amount of energy consumption.At present,fossil fuels still occupy the main position in China’s energy consumption.And the consumption of fossil energy has caused serious air pollution,leading to the frequent occurrence of haze weather in many areas of China,people’s health has been seriously threatened.Countries attach great importance to the governance of the atmosphere and,therefore,carbon emissions,the country has issued a “about promoting the implementation of the steel industry’s opinions on ultra-low emissions and affairs of the iron and steel enterprises in surveillance of ultra-low emission assessment notice”,strict rules flue gas dust content of iron and steel industry,it serves to show national determination of atmospheric pollution control.The research shows that the filter efficiency of electric dust removal on fine particles is much less than that of bag dust filter,and it cannot meet the standard of ultra-clean emission.With the increasing efforts of national environmental governance,bag-type dust removal filter has gradually become the main filtering means.Filter bag is mainly composed of disorderly arrangement of fiber net and base cloth composite reinforcement,and then after a series of post-processing procedures,so that the filter material has other special functions.After acupuncture in the filter material,the fiber net plays a role in filtering fine particles.Base cloth is used to strengthen the mechanical properties of the filter bag,so that the filter bag can withstand the external impact force in the process of dust removal,and prolong the service life.Because the core function of the filter bag is filtering,especially the filtering of small particles,and it also needs to meet the severe shock in the process of ash removal,the filter material needs to take into account the two basic indicators of mechanical strength and filtration efficiency.In the production process of filter material,the uniformity of the fiber net has a significant effect on the filter efficiency.The carding effect of the carding machine directly affects the uniformity of the fiber net.When the carding is insufficient,the degree of mono-filtration is low.When the carding machine outputs the fiber net,there will be the occurrence of fiber agglomeration,resulting in the uneven fiber net.When the carding is excessive,the fiber is excessively carded in the process of carding,the fiber may break,the content of short fiber increases,which has a negative impact on the pore diameter of the filter material,thereby reducing the filtering efficiency of the filter material.In this paper,through the cooperation with Zhejiang Yubang Filter Material Technology Co.,Ltd.,in-depth production line to learn the key technology of the industrial production of filter material,familiar with the impact of each link on the performance of the filter material.Zhejiang Yu Bang Filter Material Technology Co.,Ltd.mainly produces PET fiber and PPS sulfide fiber needled filter material,the company is equipped with foreign and domestic two production lines,the main difference is that the foreign production line is equipped with ANDRITZ carding machine.By changing the process parameters of the main cylinder and the work roll of ANDRITZ carding machine,the changes of the strength,pore size and filtration efficiency of the semi-finished filter material only after acupuncture were explored.The semi-finished filter material produced by ANDRITZ carding machine under the best technological parameters was compared with the semi-finished filter material produced by domestic production lines,and the fracture strength,pore size and filtration performance were tested respectively,and then the measured data were analyzed.The semi-finished products of filter material prepared by domestic and foreign production lines are processed by the same post-processing technology to obtain finished filter material.Comparing the fracture strength,pore size and filtration performance of the finished filter material,the following conclusions are drawn:(1)When 2.22 dtex PET fiber with a length of 51 mm was selected as the raw material and the worker speed was maintained at 50 m/min,the performance of the filter material was studied under different main cylinder speeds.According to the test results of the semi-finished products of the filter material,when the main cylinder speed is 900 m/min,the vertical and horizontal fracture strength of the semi-finished products of the filter material is higher.The average pore diameter of the semi-finished filter material is 33.34μm±4.27μm,and the comprehensive filtration performance is good.When the main cylinder speed is 1000 m/min and the worker speed is 40 m/min,the breaking strength of the semi-finished products of the filter material is higher,the average pore diameter is smaller,which is 32.25 μm±5.68μm,and the static filtration efficiency is higher.(2)Inquiry concluded that ANDRITZ,carding machine the best after the main cylinder and the worker speed,the foreign production line under the optimum technological parameter on the preparation of PET filter material preparation of normal sales semi-finished products and domestic production line,comparing the filter material semi-finished products testing performance of each filter material semi-finished products,compare and test results,foreign semi-finished products production line filter,the average pore diameter less than domestic production line.The static filtration efficiency of the semi-finished filter material of foreign production lines is higher than that of the semi-finished filter material of domestic production lines.The semi-finished products of the two kinds of filter materials are obtained by the same post-treatment process.It is found that the fracture strength of the finished filter materials of the foreign production line after the post-treatment process is slightly higher than that of the finished filter materials of the domestic production line in both vertical and horizontal.The average pore diameter of the finished filter materials of the foreign production line is 19.27μm ±6.13μm.Less than the domestic production line finished filter material 23.82μm±8.16μm.The static filtration efficiency for particles with particle size greater than or equal to 2.0μm reaches 94.96%,which is higher than that of domestic finished filter material 92.26%.The comprehensive performance of the filter material prepared by foreign production line is better than that of the filter material prepared by domestic production line.(3)When the raw material is 1.33 dtex,the length of 51 mm PPS fiber,the worker speed of carding machine is maintained 40 m/min,the main cylinder speed is 1000 m/min,the semi-finished filter material fracture strength is larger than other groups,the average pore diameter is smaller,the static filtration efficiency is higher.Then the main cylinder speed is fixed at 900 m/min.Through the test results,it is found that when the work roll speed is 50m/min,the semi-finished filter material has a higher breaking strength,the average pore diameter is small,32.04μm±4.73μm,and the group of filter material comprehensive performance is better.The parameters of carding machine are set in the optimal process parameters to prepare the semi-finished PPS filter material,and then the semi-finished product of the filter material is post-treated to get the finished PPS filter material.Test the performance of the finished filter material,the fracture strength is equivalent to the semi-finished filter material,indicating that the post-treatment technology has little effect on the strength of the filter material;The average pore diameter is far less than the semi-finished filter material,the average pore diameter of the finished filter material is 17.78μm ± 6.38μm,the filtration efficiency of the finished filter material is far greater than the semi-finished filter material.