Study On Filtration Mechanism And Experiment Of Wet Granular Layer

Nowadays,aerosol particles discharged by Industrial and mining production which take a large proportion of air pollution,cause a large waste of resources and meantime do great damage to people's health.Gravel bed filter is an efficient environmental protection dust removal technology,which is widely used in various industries for its features of high-temperature and high-pressure resistance and high efficiency of dust removal,etc.However,there still exist two problems of the traditional gravel bed filter: 1)low purification efficiency of ultra-micro fine dusts,easy to accumulate dusts and too large filtration resistance.2)Theoretical analysis is far beneath experimental research.The paper proposed an efficient compounded gravel bed filter technology combining wet dust removal technology with gravel bed filter technology to solve the problems above.Aiming at compounded dust wiper,the paper proposes the equivalence hypothesis of the balanced distribution of collection fluid on the surface of particles and make use of multivariate analysis and Darcy Law to infer the the equation of the purification efficiency of the wet gravel bed filter and damages caused by filter pressure and obtain main factors influencing dust wiper efficiency and resistance: filter material particle size,filter layer thickness,filtration velocity and filling ratio on the basis of dry-type models.On the basis of theoretical analysis we design the building of fixed bed wet granular layer experiment bed and take the method of orthogonal experiments combined with regular experiments to do research on the purification efficiency of the wet gravel bed filter and damages caused by filtration pressure in order to get the operating range of best parameters of compounded dust wipers.The formula of half theories and half experience are gained by means of formula fitting and return and non-dimensional revises of filtration resistance theoretical formula.And results compared with experimental data,theoretical formula calculation suggest the formula of half theories and half experience are closer to experimental values.We can predict the purification efficiency and filtration resistance to offer references to better choices of filter layer functions.In order to improve the purification efficiency of ultra-micro fine particles wet gravel bed filter and hydrophobic particles,the paper proposes two optimum methods: double layer particle filter layer structure of the wet granular layer and added wetting type chemical dust-depressor on the basis of best parameters and confirms the feasibility of optimum methods in experiments.Finally,it makes an original design of the embryonic form of the new-style granular layer dust collector and make the scheme of parameter selection interval and operational maintenance.