(301b) Limiting Flow Rate of Fine Powders through Hoppers – Investigation of Methods to Increase the Flow Rates

The discharge rate of fine powders through a bin or hopper tend to be much smaller compared with the famous Beverloo equation (which is applicable for coarse bulk solids). This is mainly due to the high compressibility and low permeability associated with fine cohesive bulk solids. Based on our previous work to model the two-phase flow effects of powder flow in cylindrical and conical hoppers, methods to increase the flow rate are investigated in the present work. These include air injection systems within the hoppers or installing standpipes below the hopper. Theoretical predictions of gas pressure profiles within the standpipes as a function of flow rate will be presented in this paper.