Parameteric Study On Factors Affecting Decarbonization Process Of Coal Fly Ash Based On Discrete Element Method

Fly ash,as a waste of coal-fired power generation,has been accumulating to a massive amount.On the other side,fly ash can be used as a resource after special treatment.Supporting this point,removing charcoal from fly ash is a hotspot in fly ash treatment.At present,the research on the removing charcoal from fly ash by frictional triboelectric separation mainly focuses on the optimization of process parameters,but the research on its influence mechanism is relatively less,and the explanation of some separation effects is still lacking.In this paper,the effects of feed rate,particle size and feed concentration on unburned particle charge process are analyzed in detail by EDEM discrete element simulation;the effects of feed angle and electric field strength on particle separation are also systematically investigated.The electric field separation process of fly ash has two segments.The first stage is the charging process.The collision and relative slipping between particles and charged apparatus lead to charged particles.It should be noted that the electronic properties are only related to the properties of granular materials and the size of the charge to mass ratio.So it is reasonable that this paper simply takes the coal particles as the object and explores the changes in the average charge to mass ratio of coal particles under different feeding speed,particle size and particle concentration.The results show that the larger the incident velocity of particles,the better the charged condition of particles will be.The results also indicate that proper particle concentration leads to fully mixed particles and thus a better-charged particle cluster.Besides,the charging process also has a positive relation to smaller particle size.The second stage is the separation process.As coal particles and fly ash particles carry opposite electronics,they get separated easily in the electric field.In this paper,EDEM numerical analysis software is applied to study how the feeding angles and electrical field strength affect the separation process.The evaluation is fulfilled by counting the particle number and catalogue in the different receiving slot.The results show that in the left electric field,the smaller the incident angle,the better the separation effect;in right electric field,the incident angle has no obvious effect on the separation effect;Specifically,the larger the electric field strength is,the better the particle separation performance will be.