Research On Characteristics And Applications Of Wet Metal-based Mesh Filtration Dust Collection

Large amounts of fine dust particles are generated during the process of coal mine production,which seriously affects the safety of coal mine production and endangers the occupational health of workers.Traditional wet dust collectors such as wet vibrating string dust collectors and wet fiber layer dust collectors have played an important role in dust prevention and control of coal mine.However,there are still shortcomings such as low dust purification efficiency and high operating resistance,which cannot meet the strict requirements of the country for occupational health in the new era.In order to solve the problem of industrial dust pollution in coal mines,improve the efficiency of dust purification,and reduce the operating resistance of dust collectors,based on the synergistic effect of nozzle atomization dust reduction and metal-based meshes wet filtration dust removal,this thesis proposes a new idea of wet metal-based meshes filtration dust removal,and develops a wet metal-based meshes filtration dust removal system.By means of theoretical analysis,experimental research and field test,the spray-filtration coupling dust removal process of wet filtration dust removal system is analyzed.The atomization characteristics of nozzles under the condition of multi factor coupling are revealed.The influence characteristics of key operating parameters of wet filtration dust removal system are studied.The optimal installation mode of metal-based filter meshes is determined.And the multi-stage efficiency improvement strategy of wet filtration dust removal system is proposed.This provides scientific guidance for the design and optimization of wet filtration dust removal system.The main research conclusions are as follows:The spray disturbance experimental system was constructed with a laser particle size analyzer.Moreover,the influence of multi-factor coupling conditions(such as nozzle aperture,spray pressure,and ambient wind speed)on the atomization characteristics of nozzles was studied.The results show that:(1)the nozzle spray angle increases with the increasing nozzle aperture and decreases with the increasing spray pressure and intensifying ambient wind speed;it gradually stabilizes when the spray pressure exceeds 0.9 MPa.(2)Higher spray pressure and larger nozzle aperture indicate greater spray flow,while ambient wind speed has no effect on it.When the nozzle aperture is greater than 2.4 mm,the spray flow increases significantly.(3)The overall atomization performance of the nozzle improves as the spray pressure increases or the nozzle aperture decreases.(4)The optimal atomization area(at a distance of 30 mm from the nozzle)is irrelevant to the spray pressure and nozzle aperture,but the distance increases with intensifying ambient wind speed.A small-scale wet filter dust removal experimental system was built to explore the effects of single-factor conditions(such as spray pressure,filtration accuracy,and filtration velocity)on the comprehensive performance of wet filter dust removal system.The operating parameters of the wet filter dust removal system in optimal performance were obtained under single-factor conditions.Based on the conclusions of single-factor influence,an experimental model with multi-factor synergistic influence was established to analyze the variation rule of pressure drop and dust removal efficiency of wet filter dust removal system.Under different operating parameter combinations,the comprehensive performance of the wet filter dust removal system was comparatively analyzed.Then,the influence of key operating parameters of the wet filtration dust removal system was revealed.Additionally,this thesis explored the influence of different installation angles of metal-based filter meshes on the pressure drop and dust emission concentration of wet filter dust collectors.On the basis of dust emission concentration,pressure drop,and water consumption parameters,a model was proposed to comprehensively evaluate the performance of wet filter dust collectors under different installation modes.The results demonstrate that when the installation angle of the metal-based filter mesh increases from 30°to 150°,its performance index first increases and then decreases.When the installation angle is 90°,its maximum performance index is 1.84 m~3/(L·Pa),and the wet filter dust collector exhibits optimal performance.The method of improving the dust removal efficiency of the wet filter dust removal system was studied.This thesis proposed the multi-stage dust removal and efficiency improvement strategy of metal-based filter mesh.In addition,the influence of factors(such as filter mesh layer numbers,filter mesh installation spacing,and inlet dust concentration)on the performance of wet filter dust collectors was explored,revealing the relationship between each factor and pressure drop and dust emission concentration.The results indicate that the increase in filter mesh layer numbers or installation spacing leads to dust accumulation on its back layer surface.The dust accumulation subsequently increases the dust collector pressure drop and reduces its comprehensive performance.The wet filter dust collector performance is optimized when the 40-mesh and 60-mesh filters are installed with a spacing of 0 cm.The increase in inlet dust concentration only results in an enlargement of the dust emission concentration without affecting the operational stability of the dust collector.Based on the experimental research results of nozzle atomization characteristics and wet filter dust removal system performance,a mining wet filter dust collector was designed and optimized.And engineering experiments were conducted in the screening and crushing workshop of Halagou Coal Preparation Plant and the 7112 comprehensive excavation working face of Wangzhuang Coal Mine.The application results of the screening and crushing plant show that the total dust removal efficiencies of measuring points A and B at the transfer point are 89.68%and 90.10%,respectively,and the respirable dust removal efficiencies are 85.77%and 84.58%,respectively.Applying a wet filtration dust removal system can effectively reduce the dust concentration at the transfer point and ensure occupational health for workers.The application results of the7112 comprehensive excavation face indicate that at the position of the driver,wheel loader,and 5 m behind the wet filtration dust collector,the average total dust removal efficiencies are 93.64%,95.85%,and 96.21%,respectively,and the average respirable dust removal efficiencies are 88.72%,91.15%,and 92.79%,respectively.Hence,the dust removal effect is remarkable.This thesis consists of 90 diagrams,19 tables,and 182 references.