(125b) Modeling Limiting Flow Rate of Fine Powders through Hoppers

Authors: 
Kodam, M., The Dow Chemical Company
Jacob, K., The Dow Chemical Company
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.

In this work, the original model of Johanson (1979) is used to predict the limiting discharge rate of fine powders through conical hoppers. The gas and solids governing equations are solved in MATLAB® and results are presented for some fine powders. Using this model, the effect of fill height and powder bulk properties (compressibility, permeability, internal angle of friction) on the final discharge rate are investigated.