Theoretical And Application Research Of Wet String Grid Film Dust Removal In Air Shaft

With the continuous improvement of mining mechanization level,a large amount of dust is produced in the operation point.Because there are many and scattered underground dust producing points,although dust prevention measures are taken in the operation point,the effect is not ideal.A large amount of dust comes to the exhaust shaft with the return air flow,which seriously pollutes the surrounding environment of the mining area and endangers human health.In this paper,the theoretical derivation,numerical calculation,experimental test analysis and engineering application are combined to carry out the research,and the wet string grid dynamic film-making dust removal theory is obtained,and the optimal wet string grid dust removal working parameters are obtained,which provides theoretical and technical basis for efficient and low resistance dust removal,cleaning treatment of mine exhaust shaft.Based on the basic theory of spray technology,dust removal technology and equipment and capillary mechanics,the mechanism of water mist and water film dedusting for wet grid is analyzed theoretically.The wetting mechanism of water mist on the chordal plate and the distribution rule of water mist and water film are explored.The mechanism of film formation and the mechanism of film formation and disintegration are discussed.The combined dust removal mechanism of multi factors is deduced,and the dust removal efficiency and dust removal of the combined dust removal of water mist and water film are deduced.The resistance expression shows that the dust removal velocity,spray water,spacing and filling rate of exhaust chill are the main factors that affect the efficient and low resistance dust removal of wet grid,and the mechanism of high efficiency and low resistance dust removal for wet grid is explained.Based on Realizable k-ε turbulence model and DPM model,the velocity field and droplet distribution of wet string grid filtration system were numerically simulated and analyzed by using ANSYS FLUENT software,and the velocity field nephogram of the string grid filtration system and the droplet mass concentration distribution before and after the string grid were obtained under different dust removal wind speed conditions.The results show that a high-speed zone similar to "bullet" is formed between the wires,and the dust removal wind speed has a significant effect on the string grid filtration;Combined with the theoretical expression of dust catching efficiency of droplet group,the dust catching efficiency of droplet group at different positions in front of chord grid is calculated.In addition,MATLAB software is used to calculate and analyze the water film rising height,water film area,dedusting efficiency and dedusting resistance.The experimental system of wet string grid dust removal was designed 320 laser diffraction particle size analyzer is used to analyze the particle size and distribution of the selected dust.The dust used in the experiment is screened out.Combined with theoretical deduction,the factors that affect the dust removal of the wet chordal grid are found.Based on the expressions of dust removal efficiency and dust removal resistance,the experimental scheme of wet string grid water film dust removal is designed.The relationship between the dust removal velocity,the spray water,the spacing between different chords,the filling rate of different chords and the efficiency of dust removal and the dust removal resistance are studied,and draw a regular conclusion.Finally,based on the two principles of "high efficiency and low resistance" and "economic application",the four factors that affect the efficiency and resistance of dust removal are analyzed one by one,so as to determine the best level of the influencing factors,namely,the best value of dust removal wind speed is 3m/s,the best spray water is 5.9L/min,the spacing between the chill steel wires is 0.26 mm,and the optimμm value of grid filling rate is 46%.In addition,the experimental value and theoretical value of wet string grid dust removal efficiency and resistance were compared and analyzed under different working conditions.The results show that the dust removal efficiency of the theory is consistent with the experimental dust removal efficiency in general,and increases with the increase of spray pressure.The theoretical dust removal resistance and experimental dust removal resistance keep a high degree of consistency in the overall trend,and increase with the increase of dust removal wind speed.After the above research results are applied to Xinnan air shaft of A Lead zinc mine.Under the conditions determined by the experimental study,the average dust removal efficiency is 94.94%,which indicates that the effect of wet string grid water film dust removal is remarkable,and it can effectively reduce the dust emission concentration of the air shaft.