Moisture adsorption characteristics of a thin bed of polycrystalline potash pellets: Part I. Experimental study

This study is an experimental investigation of heat and moisture transfer within a packed bed of polycrystalline, porous potash pellets. Experiments were first performed to determine the moisture uptake characteristics on individual pellets subject to a step-change in relative humidity. Then a bed of pellets was subjected to flows of humid air on the upper boundary and a cold impermeable surface on the lower boundary resulting in a temperature gradient across the bed. Temperature and moisture content were measured within the bed. It was found that moisture uptake is less for potash pellets and they are less likely to cake than granular and standard potash when subjected to the same ambient air conditions. This is due to the porous nature of the pellet and its nearly uniform size and spherical shape.

In this paper the moisture adsorption characteristics of polycrystalline, porous potash pellets that were subjected to step changes in relative humidity is examined. In one set of experiments the pellets were exposed to stagnant conditions and in the second set the pellets were exposed to flow across the bed. It was found that moisture uptake levels are lower for this type of potash pellet than for other potash types and that these pellets are also less likely to clump together after drying.Figure optionsDownload as PowerPoint slide