Mathematical interpretation of kinetic patterns of beet shavings drying

The article investigates the heat and mass transfer kinetics during the drying of beet pulp in a drum dryer with a channel nozzle. The study focuses on analyzing the impact of key process parameters: drying agent (air) temperature (403–413 K), airflow rate (0.312–0.437 m³/s), drum fill level (30–35%), and rotation speed (1–2 rpm). Experimental research was conducted using a custom-designed setup ensuring hermetic sealing, real-time parameter control, and sampling without depressurization. Product moisture content was determined via drying at 378 K, following the TU OST 18–22–81 standard. To enhance efficiency, wheat bran was mixed with raw beet pulp to absorb moisture and reduce energy consumption. The results indicate that increasing air temperature from 403 to 413 K elevates drying speed by 15–20%, shortening processing time. Higher airflow rates and drum rotation speeds also intensify drying, while increased fill levels amplify hydrodynamic resistance, slowing the process. Kinetic curves reveal three distinct phases: heating, constant drying rate, and falling drying rate. Based on experimental data, criteria-based heat transfer equations (Nu) were derived for the constant (error ≤17.5%) and falling rate periods, incorporating the Reynolds criterion (Re), temperature simplex, and moisture parameters. An innovative two-section drum dryer is proposed, enabling sequential material treatment using hot air and superheated steam. The design features independent sections with individual drives, a screw conveyor to prevent mixing of drying agents, and an adjustable flap to regulate final moisture content (10–13%). The upgraded system enhances process intensity by 25–30% and improves product quality through section-specific temperature optimization. The findings are applicable to industrial plant design for agricultural waste processing, reducing energy consumption, and extending the shelf life of feed materials.