Convective Drying in the Multistage Shelf Dryers: Theoretical Bases and Practical Implementation

The main advantages regarding the convective drying of the granular materials in the multistage dryers with sloping perforated shelves were represented. Peculiarities of the shelf dryers’ hydrodynamics were shown in the research. Various hydrodynamic weighing modes were experimentally justified, and the relevant criteria equations were obtained. The results of investigations regarding the interphase heat and mass transfer were given; criteria dependencies, which predict heat and mass transfer coefficients in the shelf dryers, were proposed. A method to assess the efficiency of the dehydration process at the separate stages of the device and in the dryer, in general, was proposed. The algorithm to define the residence time of the granular material on the perforated shelf with a description of the author’s software product for optimization calculation was shown. The shelf dryers’ engineering calculation method was presented in this work. The original constructions of devices with various ways to control the residence time of the granular material that stays in their workspace were described. The testing results of the shelf dryer to dry granular materials, such as coarse- and fine-crystalline potassium chloride, sodium pyrosulfate, and iron and nickel powders, were demonstrated