| Industrial dust emission is the main culprit for decreasing air quality.Fine particulate matter mixed with airborne particles is the main atmospheric environmental pollutant in our country and also the main culprit for dust induced occupational diseases.Occupational dust diseases account for more than 99% of new cases in our country.Metal bag dust collector can effectively control industrial flue gas pollution,with high hardness,low resistance,large handling air volume,strong adaptability to flue gas and other advantages.However,the metal bag dust collector has some problems,such as the disturbance of the filter airflow and the failure of the upper part of the bag,which limit the stable operation of the metal bag dust collector and its advantages.In view of this,this paper analyzes the causes of the failure of dust removal at the upper part of the filter bag,and compares the effects of different types of baffles and scatters on the dust removal effect of the dust collector pulse spray.The main contents are as follows:(1)The experimental platform of metal fiber felt filter bag dust collector was built,based on which a numerical model was constructed,and the characteristics of the filter and dust flow of metal bag dust collector were studied by numerical simulation and experiment.The results showed that the increase of dust load and filtration wind speed would make the filtration flow field disordered and the pressure value of the upper side wall of the filter bag decreased.Under filtration condition,with the increase of dust load in the filter bag,the average velocity of the measuring point in line S increased from 0.35m/s to 0.71m/s,and that in line X decreased from 1.1m/s to 0.86m/s.When the inlet velocity of the dust collector is 4.5m/s and 8.9m/s,the pressure difference of the upper part of the filter bag is 49.76 Pa and 99.7 Pa,and the pressure difference of the lower part is 48.78 Pa and 95.6 Pa,respectively.The increase of the pressure difference of the upper part is 1.97% and 4.76%,respectively.In the clear ash state.The pressure on the side wall of the upper part of the clean filter bag 150 mm from the mouth of the bag is 453 Pa,and the pressure on the side wall of the lower part100 mm from the bottom of the bag is 1151 Pa.When the filter bag is loaded with dust,the pressure on the upper part of the filter bag is 251 Pa,which is lower than the cleaning requirement of 400 Pa,and the pressure on the lower part is 1720 Pa,which increases by49.4% compared with the clean filter bag.(2)A numerical simulation 3D model was constructed to explore the effects of different types of baffles on the filter flow field.The results showed that all six types of baffles could improve the uniformity of the flow field,and the optimization effects were ⅲ-0> in order.Ⅲ-10 type >Type Ⅲ-20 >Ⅱ-20 type >Ⅱ-0 type >Type Ⅱ-10.Compared with before optimization,after installing Ⅲ-0 baffle plate,the maximum flow uneven coefficient of metal bag filter decreases from 0.227 to 0.011,the comprehensive flow uneven coefficient decreases from 0.088 to 0.003,and the relative deviation of bag clearance velocity decreases from 54.8% to 29.7%.(3)put forward a kind of applicable to Φ 130 mm filter bag of metal cone diffuser,established the numerical simulation of pulse injection experiment model,analyzes the three different diffuser width on the influence of pulse injection effect.The results show that the three scatters with different widths can induce the recombination pulse jet flow,increase the pressure value of the upper side wall of the filter bag,reduce the pressure value of the lower side wall,and achieve uniform cleaning.Compared with without scatterer,the average pressure of the upper side wall of the filter bag increased from 339 Pa to 661 Pa,669 Pa and683 Pa,and the average pressure of the lower measuring point decreased from 1692 Pa to1235 Pa,1264 Pa and 1283 Pa,respectively.The mean value of the overall wall pressure increased from 1013 Pa to 54.3 Pa,66 Pa and 89.3Pa,respectively,and the root mean value of the wall pressure decreased from 0.535 to 0.246,0.247 and 0.248,respectively. |
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