Update of the procedure used for heavy clay dryer optimization

Abstract

The description of the moisture transfer in porous media during drying was the subject of many scientific studies. The unique drying theory was developed five years ago and has recently won a general recognition in the scientific community. This paper is providing the update of the recently reported method for setting up the optimal drying parameters inside the heavy clay dryer. The main goal of this paper was to find a way how to reduce the number of experiments without affecting the quality of the previously proposed calculation method. The critical drying rate, as well as the drying behavior can be easily registered inside the laboratory recirculation dryer for any heavy clay product. These data provides a clear perception of how far the real drying curve, used in industrial dryer, is away from the shortest possible one. The algorithm of the updated procedure was based on the Box-Wilkinson's orthogonal multi - factorial experimental design. The updated model outputs were represented as the governing equations which were used to predict the time intervals between any two chosen characteristic points, specified in the unique drying theory, as a function of the drying air parameters. These equations were valid for any value of the drying air parameters taken from the previously established limiting boundary range. The updated procedure was compared with the original one for two predefined drying air parameters sets. Regardless to the fact that in the first case the results were not experimentally obtained they were similar to those which were in the second case experimentally identified. This was additional confirmation that the same quality degree has been maintained in both procedures, despite the fact that the total number of experiments was lower in the upgraded procedure than in the original one.