Predicting powder caking using cohesion energy density

Abstract

Given the difficulty in quantifying the interparticle forces, both experimentally and numerically, most studies have considered only the humidity effect in powder caking. In this work, the interparticle forces in caked powders were quantified using the simplified Johnson-Kendall-Roberts (JKR) model to account for all the material and environmental factors that influences powder caking. The cohesion energy density, which is the ratio of cohesive energy to volume of the particle, was used as the indicator of caking in powders. Simulated force chain network was used to track the relay of interparticle forces (IPFL) under compression. The model was validated experimentally by using caked isomalt powder. At a consolidation pressure of 9 kPa, an increase in moisture from 6 to 8% increased the predicted IPFL from 0.41 to 1.31 N while the experimentally measured IPFEL ranged from 0.33 to 1.11 N. The corresponding cohesion energy density varied from 4.05 to 6.98 MJ/m3. This study shows the potential of using cohesion energy density as the predictor and indicator of powder caking. The conditions at which a powder is stored can be related to the cohesion energy density which then can be used as an input parameter for analyzing the caking behavior.