ENERGY-EFFICIENT CHAMBER DRYER WITH THICK ALLOY HEATING ELEMENTS

Abstract

Drying is one of the main technological processes of plant raw materials processing in the production of dry food products and powders from them. Convective drying is the most widespread method of drying vegetable raw materials, which is accompanied by high energy costs for the process. Increasing the energy efficiency of drying colloidal capillary-porous materials in a 2-zone chamber dryer occurs due to the use of coolant recirculation between drying zones and the installation of thick-film heating electric elements. The proposed design of the thick-film heating element and its technical characteristics are presented. Studies of the drying kinetics of colloidal capillary-porous plant materials were carried out on the created energy-efficient 2-zone chamber dryer with installed thick-film heating elements. Reducing energy costs for the drying process is possible through the design and manufacture of a 2-zone chamber dryer with the installation of 2 sections of thick-film heating elements (21 pieces in each). Installing this heater in a chamber dryer allows you to save electricity consumption by up to 30 %. The study of the kinetics and energy efficiency of the drying process in a chamber dryer is carried out on colloidal capillary-porous materials, in particular potatoes and pumpkins. The intensity of drying is limited by the quality characteristics of the material, so drying is carried out at low temperatures. Material quality control is assessed by recoverability and organoleptic indicators after drying. The results of experimental studies in a chamber drying unit showed that energy costs for the drying process increase significantly at the end of the process when the intensity of moisture evaporation decreases. The energy consumption of heat per kilogram of evaporated moisture and the efficiency of the installation were analyzed in order to determine the optimal drying time. Energy consumption per kilogram of evaporated moisture in the created chamber dryer corresponds to the effective indicators of this type of convective dryers. Bibl. 20, Fig. 8.