Experimental Study On Conduction Induction Separation Of Fly Ash And Its Numerical Simulation

Fly ash is a major by-product of coal-fired power plants,which has an enormous yield and increases year by year.Without effective treatment and utilization of fly ash,it will cause a certain degree of pollution and damage to the environment,but also a huge waste of resources.Therefore,it is of great concern to improve the comprehensive utilization of fly ash.The important factors that affect the quality of fly ash are the content of unburned carbon in fly ash,and the unburned carbon itself has a high utilization value,so it is very significant to study the fly ash sorting technology.As electrostatic separation technology is simple,economic,and environmental,so it was paid more and more attention.In this thesis,the separation of fly ash is studied by using the method of conducting inductance induction.This equipment has a reasonable structure of the equipment,handling capacity and other characteristics.And it has been widely studied and applied in the beneficiation industry,but no such equipment has been applied to fly ash sorting.In this thesis,the samples were analyzed systematically,including particle size distribution,physical and chemical properties,appearances of the samples.Then,the influence of various factors on the sorting of fly ash was analyzed by sorting test bed and numerical simulation.Finally,the mixed orthogonal test was used to study the multi-stage sorting of fly ash,and the optimal level combination was determined by analyzing the test results.Through the conduction induction single-stage sorting test study shows plate types have great effect on sorting,the concave arc plate has better sorting effect.The plate voltage and the board spacing have significant influence on the sorting.With the increase of the voltage between the plates,the sorting effect between the concave arc plates is increased first and then decreases,and the best sorting effect is obtained when board spacing is 6cm and voltage is 7.5kv.The separation of particles with different particle size are also different,Particles,which particle size between 75-104μm,have the best sorting effect.By analyzing the sorting product,unburned coal of tail ash is mainly distributed in the fine ash whose particle size<75μm.Using the Discrete Phase Model of the FLUENT software for simulation of the trajectory about the fly ash particles,and the carbon content and yield of the ash products were calculated.Through the comparison of sorting effect,the concave arc plate shows better sorting effect than the flat plate and convex arc plate;Particle inlet speed increases,the carbon content of the ash products will increase,but the yield will be reduced.With the increase of particle size,the carbon content of ash is increasing,and the yield is gradually reduced,and the recovery rate of carbon is the highest when the particle’s size is 50μm.The analysis of mixed orthogonal experimental results show that the optimal combination of fly ash sorting concluding the voltage V1 is 10kv,the voltage V2 is 7.5kv,the board spacing is 10cm,the third inlet is the fine ash,the fourth grade is the horizontal combination of the upper tail ash.