Purpose. To improve the efficiency of mass and heat exchange processes in agricultural production (increase in productivity, decrease in specific energy consumption while maintaining or improving the quality of finished products) by optimizing the operating modes of energy-efficient equipment for drying agricultural raw materials.
Technical properties. The proposed design of the convective dryer SGK-4 “TIRAS” with the following technical characteristics: dryer type – convective; drying chamber volume – 4.0 m3; internal diameter of the drying chamber – 1800 mm; nut weight in the drying chamber – up to 1000 kg; productivity – up to 2000 kg / day; drying intensity – 1-2% per hour; drying process duration – 10-15 hours; heating element type – electric heating element; heating element power – 12 kW; fan capacity – 1550 m3 / hour; fan motor power – 0.55 kW; Fan speed – 1500 rpm; Auger diameter – 300 mm; Auger pitch – 150 mm; Auger speed – 25-45 rpm; Auger drive power – 0.55 kW; Auger drive motor-reducer brand – 3MP-31.5-45-0.55-G320; Auger drive electric motor – AIR71A4; Supply voltage – 380 V; Equipment weight – 950 kg; Overall dimensions – length (1920 mm), width (1920 mm), height (3000 mm).
Sector of application. Agriculture
Advantages. The use of a convective walnut dryer in the developed technology, compared to existing technologies, allows for: Fast and high-quality drying of walnut kernels with a safe air flow temperature (up to 60 °C); uniform moisture removal throughout the mass of nuts; reduced damage to walnuts for long-term storage; reduced energy consumption for the drying process.
Technical and economic effect. The use of the SGK-4 “TIRAS” convective dryer in the developed walnut drying technology allows for an adequate level of automation, increases the quality of the dried product and production profitability by up to 15%, reduces the cost of drying by UAH 89 per 1 m3, reduces energy costs by UAH 45 thousand without increasing the price of the sold material.
Description. The design and technological scheme of a convective walnut dryer has been developed and substantiated. It is made in the form of a mixer with a vertical screw working element with a lower injection of a warm air flow. Using the Star CCM+ software package, a simulation of the drying process in the developed convective dryer has been carried out. The process of redistribution (mixing) of walnuts in the drying chamber under the action of a screw working element and the distribution of air flow velocity and temperature in the drying chamber of a convective dryer were visualized. According to the variation coefficient, it was found that the mixing quality was better (δ = 0.92±0.02) and remained at this level after 392 s from the start of rotation of the screw working element. It was found that a temperature gradient was observed in the working zone of the dryer: in the lower part the temperature was 58±2 °C, in the upper part – 43±2 °C, which ensures the preservation of high technological qualities of the nut.