Optimization Design of an Aerated Hopper for the Cohesive Pulverized Coal Discharge

Aeration has been proved to have a positive effect on the powder flowability and the this technology which has the advantage of low cost and low noise, has been widely used in the discharging of adhesive powder. In this work, experimental of pulverized coal discharged from the aerated hopper were carried out on a plexiglass hopper. The discharge characteristics of pulverized coal was analyzed with the variation of aerated methods in order to obtain the optimal aerated condition. The result showed that aeration can promote the discharge of pulverized coal remarkably, and the effects of aerated height and aeration rate which indicted a coupled effect were discussed one by one. A mathematic model was built considering the relative motion between bubbles and particles, on the basis of the theory of bubble motion. The relationship between bubble size and aerated condition was obtained based on the regression analysis of the experimental data. With this model, it is possible to discuss the motion mechanism of powders inside the hopper and to provide the optimal aerated height as well as the optimal aeration rate for the experimental system. Model predictions were compared with the experiments with a good agreement. This work will provide some reference for the hopper design and optimization operation for the cohesive powder discharge.