Determination of Energy-Saving Drying Modes in Vibrofluidized Bed Apparatus

Abstract

The traditional pectin production technology is highly energy-intensive and environmentally unsafe. One of the possible ways to improve the technological process of pectin production is to dry directly the petine hydrolyzate before it is precipitated with ethyl alcohol. The most effective method of drying pectin hydrolyzate is drying in a vibrofluidized layer of an inert material, which provides high productivity in terms of evaporated moisture per unit volume of the chamber and the quality of the resulting dry product. This paper proposes a method for optimizing the drying process of pectin hydrolyzatein the apparatus of a vibrofluidized layer of an inert material, which makes it possible to determine the values of regime parame- ters at which the drying process proceeds with minimal costs for thermal and electrical energy. The technique is based on the experimentally obtained relationship between the specific productivity of the drying unit and the following operating parameters of the drying process: the air velocity in the drying chamber, the initial air temperature, the specific load related to the area of the gas distribution grid, the initial concentration for dry substances. On the basis of this experimental dependence, the criteria for assessing the reduced costs for heat and electric energy are formalized. A complex criterion for optimizing the drying process in a vibrofluidized bed is formulated, the minimization of which makes it possible to increase the efficiency of the drying process. Restrictions on the ranges of variation of the operating parameters of the drying process are formulated  as well. The posed problem of optimization of the drying process in a vibrofluidized  bed is solved numerically using the method of sequential quadratic programming and recommendations are formulated on the values of operating parameters for conducting the process in the optimal mode.