Development of an engineering calculation methodology for a fluidized bed drying unit

The food drying process is one of the most energy-intensive and technologically complex operations in the food industry, which directly affects the preservation of product quality and shelf life. Traditional drying methods are often accompanied by loss of nutrients and degradation of organoleptic properties, which requires the development of more efficient technological solutions. The use of fluidized bed dryers, which provide intensive heat and mass transfer, reduce thermal damage to raw materials and contribute to the production of high-quality products, is considered a promising area. The paper presents a technique for engineering calculation of a fluidized bed dryer for polydisperse materials. The methodology includes dependencies for determining the speed of movement of the drying agent, calculating the hydraulic resistance of the installation, as well as the drive power of the agitators. The implementation of the proposed computational approaches made it possible to develop a dryer design with rotating horizontal shafts with agitators. This arrangement prevents the formation of product lumps, promotes uniform particle distribution, and at the same time does not create significant hydraulic resistance. The results obtained demonstrate that the application of the developed methodology and design solutions ensures an increase in the economic efficiency of the process, an improvement in the quality of rehydrated products, and an expansion of the practical use of fluidized bed dryers in the food industry.