Simulation of static drying and drying with intermittent rotations in a horizontal drum of rice used in the cultivation of Metarhizium anisopliae

Abstract

The drying of rice inoculated with Metarhizium anisopliae, traditionally carried out in the industry by opening the cultivation plastic packages in climate-controlled rooms, faces significant limitations regarding process productivity and scaling up. This study presents an innovative approach for the technological enhancement of rice drying, utilizing a horizontal drum partially filled and operating both statically and with intermittent rotations. A two-dimensional mathematical model considering purely diffusive mass transport was employed to simulate static drying. The results indicated that 23 days are required to reach a moisture content of 0.250 kg of water per kg of dry mass, with air flowing at 50 L/min in the drum headspace and at a temperature of 30 °C. The intermittent operation mode was carried out by rotating the drum at every 24 h and every 1 h and a reduction of 82.61 % and 97.79 %, respectively, were observed compared to the purely static operation mode. The mathematical models agreed with the experimental data, confirming their effectiveness in predicting moisture profiles and enabling scale-up studies.