Improvement of equipment in order to intensify the process of drying dispersed food products

Abstract

One of the most common and investigated processes in the food industry is the drying process; this is the final stage of technological protocols that defines quality of a resulting product. It has been established that the drying process intensified due to the effective utilization of a dryer's volume and the increased phase contact surface, thereby bringing down the cost of the dried product. It has been determined that the increase in the relative velocity of the dispersed and gaseous phase increased in turn the driving force of the drying process and reduced the heat-carrier consumption for drying. It has been found that the use of an inert carrier increased the relative velocity of the phase contact surface. Theoretical and experimental studies have been conducted, which made it possible to derive empirical correlations, necessary for the engineering calculation of design features of the dryer with a pseudo-liquefied layer of inert carrier for drying the dispersed food products. The main features of the installation for drying dispersed foods are as follows: first, the upper part of the chamber hosted a device to capture the product, which prevented the release of an inert carrier along with the particles; second, the use of fluoroplastic crumbs enabled the intensification of the drying process as a result of an increase in the heat-and-mass exchange surface; third, the application of a fan and a heater made it possible to obtain a dry hot air of the required temperature, thereby preventing darkening of the product. When designing the drying unit, we established the basic requirements for ensuring uniform drying throughout the entire volume of the drying chamber at high technical and economic indicators: minimum dimensions, as well as minimum cost of materials to construct the dryer, minimum consumption of heat and electricity to dry one kilogram of raw materials, simple maintenance, decrease in the cost of equipment repair, low cost of fabrication, simplicity and reliability of operation. Our comparison of calculations based on an energy efficiency index has determined that the energy efficiency of the designed dryer outperformed a standard dryer model by 0.25 %.