Study On Dust-Cleaning Characteristic Of Pulse-Jet Bag Filter

In recent years,with the rapid development of heavy industry,chemical industry,construction,transportation and energy industries,various types of suspended dust generated have increasingly threatened people’s lives and production safety.With stricter dust emission standards,the requirements for dust removal equipment application technology are also increasing.Pulse jet bag filter is widely used for governance of cement,building materials,metallurgy,electric power,food,machinery,chemical industry and other industries for its advantages of stable and reliable performance,simple operation,high dust removal efficiency,and high concentration of fume-containing gas.As a special bag filter,the filter dust collector only needs to replace the filter bag as the basic filter element for the dust removal of the porous filter material.However,due to the current non-uniform ash cleaning,the upper dust layer of the filter cartridge/filter bag cannot be removed and the cleaning dust is ineffective,increasing the filter dust removal resistance of the filter cartridge/filter bag;the cleaning strength of the filter cartridge/filter bag is too large and the filter cartridge is too large,leading to the filter bag is destroyed in a short time,shortening its service life.In this paper,diffuser that can induce the diversion effect is designed by means of the numerical simulation and the self-made pulse injection experiment method,based on the traditional pulse jet cleaning system.By changing the flow field structure,the characteristics of dust cleaning of the pulse jet filter cartridge is studied.By exploring the mechanism of pulse jet cleaning,analysising of internal dust flow field conditions and the influence of the injection aperture,injection pressure,spray distance,diffuser structure,the height of the diffuser installation and filter cartridge measurement point on the sidewall pressure peaks of the filter cartridge,to solve the difficulty of cleaning.The CFD numerical simulation software was used to establish a two-dimensional steady-state or unsteady-state pulse deashing numerical model,and a self-programming UDF was introduced.With diffuser(different size,angle,and distance from the top of the diffuser to the orifice,whether the hole is open,etc.)or traditional cleaning methods was used for analysis the internal flow field of the pulse dust collector show that compared with the conventional pulse jet cleaning cleaning,the increase of the induced open diffuser on the structure can reduce the pressure on the sidewall of the filter cartridge and increase the pressure on the upper side wall of the large filter cartridge.It not only improves the unfavorable phenomenon of cleaning caused by the negative pressure in the upper part of the filter cartridge,but also avoids that the main air flow directly hits the bottom of the cartridge and shortens the long service life of the cartridge.However,with the increase of diffuser opening,the induced amount of airflow increases,and the distribution of pressure on the side wall of the filter cartridge tends to be unevenly uniform.During the pulse jet cleaning process,the first impact of the air flow on the filter cartridge is critical,and the maximum pressure peak on the side wall of the cartridge can make the cleaning more thorough.Different dust-inducing structures are used,and the cleaning process inside the dust collector is also different.In the single-factor ash cleaning experiment,the upper open diffuser and the side wall open diffuser were mainly studied.The two types of diffusers have different diversion effects,but they all can improve the cleaning effect of the filter cartridge.In the orthogonal test process,the main factors that affect the pressure peak of the filter cartridge sidewalls are the distance between the filter cartridge,the pulse injection pressure,the injection tube injection orifice,the injection distance,and the upper open diffuser cone angle.The analysis shows that the influence of various factors of the pulse injection process on the pressure peaks of the sidewalls of the cartridge is: the distance between the filter cartridge,the pulse injection pressure,the cone angle of the upper open diffuser,the injection aperture of the injection tube,and the injection distance.The optimal pulse cleaning combination in this experiment was the middle point of the filter cartridge,the injection pressure was 0.6 MPa,the upper open diffusercone angle was 64 °,the injection aperture was φ22 mm,and the injection distance was 180 mm.