This paper describes a nutrierical investigation of heat and moisture transfer in a bed of porous polycrystalline potash pellets. In this study a non-equilibrium mathematical model of temperature and moisture distribution within the bed was developed. Simulations were performed for a bed of potash pellets that is subjected to flows of humid air on the upper boundary and a cold impermeable surface on the lower boundary. The numerical predictions are in good agreement with the experiments and within the experimental uncertainty bounds. The model predicts that beds of porous potash pellets will contain less moisture than other types of potash fertilizer beds that are exposed to the same environmental conditions. The predictions also indicate that most of the accumulated moisture will be located in the top 10% of the bed and that the pore space relative humidity will be much greater than the supply air relative humidity. (c) 2006 Elsevier B.V. All rights reserved.