Evaluating the Suitability of Drying Rough Rice Using Heated Husk as Moisture Adsorbent

Abstract.

The main goal of this research was to study the effects the utilization of heated rice husk (20^oC to 107^oC), residence time (0 h to 5 h) and rice husk to rough rice ratios (1:2, 1:4, 1:6, 1:8 and 1:10 kg kg^-1) on the moisture reduction and drying rate. Heated rice husk, in the present study, was used as a solid heat transfer medium and a moisture adsorbent during the drying process. Increasing the rice husk to rice ratio showed a lower temperature during the first hour of the cooling stage, particularly with the higher temperatures levels greater than 40°C. The highest temperature range was very clear at the husk temperature level of 107°C. A 4.0% moisture reduction of rough rice could be achieved by employing heated rice husk at 107^oC and mixing the rice husk to rough rice by 1:2 weight basis. Increasing the husk to rough rice ratio decreased the rough rice-drying rate. The highest drying rate of 3.87%/h was achieved during the first hour after the mixing process under the husk temperature of 97^oC and the husk to rice ratio of 1:2. The first hour of the drying process proven to be the most effective duration as evident by the highest drying rate.