Research On Improving The Cleaning Performance Of Filter Cartridge With Inner Guiding Cone For Dust Removal Using An Annular Slit Nozzle

Cartridge filter performs well in the dust purification and has advantages such as a large filtration area,simple structure,low operating resistance,and low energy consumption.Currently,pulse-jet cleaning is commonly used in cartridges.However,it cannot clean dust evenly,and it upper part of the filter cartridge cannot be cleaned thoroughly.To improve the pulse-jet cleaning performance of caridge filter,this study focused on the dust removal filter cartridge with an inner cone deflector in the guide flow and built an experimental system and numerical simulation model to investigate the improvement effects of the annular slit nozzle(hereinafter referred to as the ring nozzle)and venturi tube on the pulse-jet cleaning performance of the cartridges.The main contents are as follows:(1)CFD numerical models were used to simulate the jetting performance.Also,grid independence and experimental verification were carried out to investigate the internal flow field characteristics of the dust removal filter cartridge and study the effects of the injection distance and venturi tube addition on the injection effect.It turned out that:(i)Compared with the use ordinary nozzles,the negative pressure in the upper cartridge almost disappeared after using the ring nozzle.It increased internal pressure of the cartridges and enhanced the jetting intensity;(ii)The jetting intensity of ordinary nozzles and ring ones first increase and then decrease with increasing jetting distance,with the improving uniformity of jetting.The jetting performance for the ring nozzle will be best at the distance of 400 mm.Its jetting intensity increased by 44% compared to the ordinary one;(iii)The ring nozzle can drew more airflow into the cartridges.Within the diameters of 60-160 mm,the amount of airflow first increased and then stabilized with increasing diameter,as wel as the gas quality and flow.In addition,the jetting intensity first significantly increases and then slightly decreases with increasing diameter.The jetting intensity was maximum if the diameter was 120 mm: 950 Pa,and its corresponding coefficient of variation is 0.053.(2)Numerical simulation was used to study the effects of the installation position,throat diameter,and height of the venturi tube on the jetting performance.The results showed that:(i)Installing a venturi tube on the opening above the cartridge could significantly increase the peak pressure inside the cartridges.With increasing installation height of the venturi tube,the jetting intensity inside first increased and then slowly decreased,and the jetting uniformity first decreased and then improved.The venturi tube installation position of-30 mm resulted in the largest increase of jetting intensity(29%);(ii)When the throat diameter of the venturi tube ranged from 80 to 130 mm,the jetting intensity first increased and then stabilized with increasing throat diameter.And the overall jetting uniformity would be improved:the maximum jetting intensity was achieved when the diameter was 120 mm.It would be 1187 Pa,and the corresponding coefficient of variation was 0.049;(iii)When the height of the venturi tube changed from 60 to 160 mm,the jetting intensity first increased and then decreased with increasing height.Similarly,the jetting uniformity was also improved.The jetting intensity will be strongest at a height of 100 mm,which was 1172 Pa,and the corresponding coefficient of variation was 0.070.(3)Offline pulse-jet cleaning and online dust filtration-cleaning experiments were also carried out.It turned out:(i)In offline pulse-jet cleaning experiments,the ring nozzle had a larger intensity and better uniformity in jetting than the ordinary one when the jetting distances was 200-700 mm.Under this environment,the jetting intensity was 619 Pa which increased by 16% and its coefficient of variation was 0.187 which decreased by 44% compared to the ordinary nozzle.Moreover,the optimal jetting distance for the ordinary nozzle is 500 mm,and that for the ring one is 400 mm.(ii)Online dust filtration-cleaning experiments showed that after the use of the ring nozzle,the residual pressure drop decreased by 8%.Through the combination of the ring nozzle and venturi tube,the residual pressure drop decreased by 6%compared to that of the ordinary one and venturi tube.Different combinations didn’t have a significant impact on concentration of dust emissions.When the ring nozzle was used,the mass of fallen dust increased by 6%.When the ring nozzle and venturi tube were used together,the mass of fallen dust increased by 11% compared to that of the ordinary one and venturi tube.The comprehensive performance of the ring nozzle improved by 7% compared.When the ring nozzle and venturi tube were used together,the comprehensive performance improved by 5% compared to the joint use of the ordinary nozzle and venturi tube.From the actual observations of residual dust on the surface of the filter cartridges,the author found that the ring nozzle effectively improved the insufficient cleaning of the upper part of the cartridges,and the added venturi tube further enhanced the cleaning effect.