Drying of rice using an LPG-fueled rotary dryer

This study aims to analyze the performance of a rotary dryer in the grain drying process using an experimental research method. Drying was carried out at an operating temperature of 55 °C for 180 minutes, with temperature and grain moisture content monitored hourly. Observed parameters included hot plate temperature (T_P), drying chamber temperature (T_R), outlet air temperature (T_out), ambient temperature (T_L), and drying efficiency. The results showed that the drying system temperature was stable throughout the process, with TP ranging between 85–95 °C, T_R  between 50–60 °C, and Tout slightly lower, indicating effective heat transfer from the heat source to the material. The grain moisture content decreased from 23% to 18.61% in the first hour, 14.01% in the second hour, and 11.45% in the third hour. The highest drying efficiency was achieved at 30% at the 60th minute, then decreased to 20% at the 180th minute as the material moisture content decreased and heat loss increased. Overall, the results of this study indicate that the rotary dryer is effective in reducing the moisture content of grain to a safe storage level (11–14%) with even heat distribution and good thermal efficiency. Therefore, this system has the potential to be applied to small- to medium-scale grain drying.