Powder Technology, Vol.357, 186-192, 2019
Design optimization of an aerated hopper for discharge of cohesive pulverized coal
In this paper, pulverized coal was discharged from an aerated hopper at various aeration conditions, i.e., different aeration rates and aeration heights. The discharge characteristics of pulverized coal were analyzed in order to obtain the optimal aeration condition. The result showed that both aeration rate and aeration height could affect the discharge of pulverized coal. Discharge regions were divided and related to the different powder states inside the hopper. The ideal arch above the hopper outlet was analyzed. Its height was obtained during gravity discharge and its dependency with aeration was discussed. Maximum discharge rates under idealized aeration conditions were predicted and compared well with the experimental data. From the general equation for powder discharge and on the basis of the bubble motion theory, a mathematical model was built to predict the aerated discharge rate. With this model, it is possible to discuss the motion mechanism of particles and bubbles inside the hopper and to relate the optimal aeration height to the optimal aeration rate under idealized aeration condition. A logical algorithm for optimization design of aerated hopper was further proposed, which would be able to provide some reference for the aerated hopper design. (C) 2019 Elsevier B.V. All rights reserved.
Keywords:Pulverized coat;Aerated hopper design;Idealized aeration condition;Discharge rate;Logical algorithm