Optimization Study On Dust Cleaning Structure Of Low Pressure Pulse-jet Bag Filter

As an important dust removal equipment, pulse-jet bag filter has been widely usedin metallurgy, electric power, chemical industry, environmental protection and otherfields because of its high filtration efficiency, large gas processing and good cleaningeffect. Bag filter operation shows, the suitable filtration material, bag interior flowfield uniformity and excellent cleaning system are the three key factors to ensure thesuccessful operation of the bag filter. Excellent cleaning system depends on itsscientific design, and cleaning system scientific design requires studying theperformance of the dust cleaning deeply.The dust cleaning mechanism of the bag filter was firstly summarized in this study,and the peak pressure was selected as the evaluation index that measures theperformance of the bag filter; the experimental bench of the pulse dust cleaning wasbuilt, and the effect of venturi tube structure on the dust cleaning performance of thebag filter was tested. Then, on the basis of the model experimental studies, thenumerical calculation model of a single filter bag was established, and the numericalcalculation model is validated; the dust cleaning flow fields of the industrialapplication of the bag filter in different operating and structure parameters werestudied by using numerical simulation method. Finally, the effect of the nozzlediameter, jet height, throat diameter of the venturi tube, venturi tube and bag length onthe dust cleaning performance were studied based on the response surfacemethodology (RSM) using the statistical software Minitab V15, and the quadraticpolynomial prediction model of the above five impact factors was also developed.The results show that:(1) Within the scope of model experimental studies of this study, the dust cleaningperformance of the bag filter is better than that of the bag filter without venture tube,and the throat diameter of venturi tube has less impact on the pulse dust cleaningperformance, while the effect of the length of venturi tube on the pulse dust cleaningperformance is obvious; the venturi tube structure has an important impact on the dustcleaning performance, and the dust cleaning system can be optimized by choosing theappropriate venturi tube.(2) The numerical results are in good agreement with the experimental test, andthe error is10%or so, which indicates that the numerical calculation model can be used to calculate the dust cleaning performance of bag filter.(3) The dust cleaning performance of the bag filter can be improved with theincrease of injection pressure. However, the injection pressure is not the bigger thebetter, the excessive injection pressure will increase the energy consumption, and leadto the increase in the cost of equipment operation; The dust cleaning performancewithin a certain time range is improved with the extension of the injection time, whenthe injection time exceeds a certain value and continues to extend the injection time,the consumption of the compressed air will increase and the peak pressure of the filterbag sidewall can not be improved.(4) The dust cleaning performance of industrial pulse-jet bag filter is improved withincreasing the diameter of the nozzle, and the lower part of the peak pressure in thefilter bag has basically stabilized; the injection system has the ideal injection height,and low injection height will lead to uneven distribution of peak pressure of the filterbag sidewall, and high injection height will weaken the dust cleaning strength of thelower filter bag; the peak pressure of the lower part of the filter bag rapidly is reducedwith the filter bag length, and too long filter bag will lead to poor dust cleaningperformance of the lower part of the bag.(5) Based on the response surface methodology, analysis of variance andsignificant examination of regression equation coefficients shows, the nozzle diameter(d/D), throat diameter of the venturi tube (de/D), and the bag length (L/D) havesignificant effects on the dust cleaning performance of the bag filter; the performanceis improved with the increasing nozzle diameter and diameter of the venturi tube, withthe increasing bag length, the dust cleaning performance is improved and thendegraded. Within the size range in this study, the dust cleaning effect is the optimalwhen d=20mm, de=60mm, and L=3360mm, respectively.