| People’s health has become a national priority development strategy,occupational safety and health problems dominated by coal workers’ pneumoconiosis seriously restrict the development of "Healthy China",thus dust prevention and control are imperative.Dust removal technology of filter cartridges is widely used in many industrial fields such as energy power,safety and environmental protection,and filter cartridge dust collector has become a new direction for the development of industrial dust collector because of its light weight,high efficiency and low emissions.The dust removal process of the filter cartridge dust collector needs to be cleaned in time,and due to the uneven distribution of pulse-jets,the cleaning effect of different positions on the surface of the filter cartridge varies greatly.In order to solve the problems of difficult dust-cleaning in the upper area of the filter cartridge,this thesis takes the ash cleaning process of the filter cartridge dust collector as the research object,combines experimental research with numerical simulation methods,analyzes the two-phase flow distribution characteristics and its main influencing factors in the pulse-jet cleaning process,optimizes the local structure and spray control,etc.to improve the ash cleaning effect,aiming to provide guidance for improving the dust removal efficiency of the filter cartridge dust collector.The main contents of this article are as follows:The experiment platform of filter cartridge pulse-jet cleaning was built,and the pulse-jet cleaning experiment under different pressures of air bag was carried out.Comparing the experiment results of static pressure distribution on the inside of the filter cartridge with the simulation results,it is found that the consistency is good,and the subsequent numerical simulation method and its results are verified.At the same time,in view of the difficulty of dust-cleaning in the upper area,a diffuser was installed under the nozzle to optimize the spray flow field.Comparing the static pressure distribution law,it is found that the installation of the diffuser under the nozzle can effectively improve the static pressure in the upper area of the filter cartridge,which is conducive to improving the cleaning efficiency of the upper area of the filter cartridge.The static pressure at the bottom of the cartridge is also reduced,which equalizes the spray flow field,which helps protect the cartridge and extend its service life to reduce dust removal costs.The simulation study of pulse-jet cleaning process of single filter cartridge based on CFD-DPM method was carried out: the physical model was constructed,CFD-DPM method and custom pulse function(UDF)were adopted,and the whole process of dust particles peeling off from the side wall of the filter cartridge,diffusing around and overflowing the box during the process of pulse-jet cleaning was studied.At the same time,based on Visual Basic,the post-processing program was independently developed,and the spatiotemporal distribution characteristics of dust with different sizes around the filter cartridge during the pulse-jet cleaning were analyzed.It is found that the proportion of different sizes dust particles decreases with the increase of particle size in the bottom area around the filter cartridge.In the middle region(0.2-0.5m),the proportion of dust particles in the range of 40-60μm is the largest,there are fewer fine particles in the top area(0.6-0.7m),and the proportion of dust particles of different sizes increases with the increase of particle size.The study of the optimized flow field of the diffuser was found to show that the diverting effect of the diffuser is remarkable,and the cross-section of the jet is forced to increase,which can act on the area where dust-cleaning is difficult in the upper part of the filter cartridge and improve the ash cleaning efficiency.The influence of the installation height of the diffuser and the size of the diffuser on the cleaning performance of pulse-jet was analyzed,and it is found that when the installation height is 90 mm and the size is 25 mm,the cleaning effect of the filter cartridge is relatively optimal.The pulse-jet cleaning process of uniseriate filter cartridge was studied: based on the study of single filter cartridge,a three-dimensional physical model of uniseriate filter cartridge composed of five filter cartridges was constructed.In order to optimize the injection control,the schemes of simultaneous jetting,sequential jetting and alternate jetting were compared to respectively study the changes of gas phase field in the pulse cleaning process.Taking the cleaning effect of PM2.5 as an example,the cleaning effect of the upper part of the filter cartridge is alternate jetting,simultaneous jetting and sequential jetting from strong to weak.In particular,the alternate jetting can effectively inhibit the "re-adsorption" of the peeling dust and improve the cleaning efficiency of the filter cartridge dust collector.Combined with the structure of the dust collector used in the research group,the three-dimensional model of the array filter cartridge was constructed and the dust-cleaning process was studied: based on the uniseriate filter cartridge,the pulse-jet operation control was optimized.Comparing the changes of the gas phase field and the spatiotemporal distribution characteristics of dust during sequential jetting and alternate jetting,it is found that each row of filter cartridges in the process of alternate jetting is less affected by the pulse-jet air flow of the previous row before its pulse injection,and the gas phase field is relatively stable.The cleaning effect of total dust and PM2.5 of alternate jetting is better than that of sequential jetting,and the total dust and PM2.5concentration on each row of filter cartridges are lower than that of sequential jetting,at the same time,alternate jetting has a weak cleaning effect on dust particles with particle sizes in the range of 20-40μm and 40-60μm,and has a strong cleaning effect on dust particles with particle sizes of 60-80μm and <2.5μm,which provides guidance for improving the cleaning efficiency of fine dust,and has important practical significance for improving the pulse injection control of filter cartridge dust collector. |
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