Abstract
The existing industrial dryers commonly used for paddy drying such as fluidised bed dryer (FBD), re-circulating batch dryer, and continuous bed dryers, despite its useful ability, have its limitation in terms of capital and operating cost, flexibility of processing in small and large scale, and requirement of skilled labours. In this study, a commercial scale Laterally Aerated Moving Bed (LAMB) dryer was designed, fabricated, and tested in a local rice mill. This new technology is consisted of a 4.7 m tall LAMB vessel containing perforated inner tube and a mesh layer, electrical air heater, and conveyor systems for paddy loading and withdrawal. The LAMB dryer had a capacity of 2 t of paddy per batch. The performance testing at ambient aeration temperature was done. The results showed that the paddy could be dried to the desired moisture content using ambient air (30 -35 °C), at a fixed air flow rate of (530 m3/h), 5 h air blowing, and 1 h tempering time. The moisture content wasreduced from 17.87 to 13.04 % (w.b.) in 5 h, and reduced further to 12.04 % (w.b.) after undergoing tempering for 1 h. The drying uniformity analysis showed that the percentage standard deviation for vertical drying analysis is 16.94 %, whereas the horizontal drying analysis recorded only 2.93 %. The drying time was shorter than the time taken by typical inclined bed dryers. The LAMB drying uniformity was relatively higher compared with the recommended uniformity by IRRI, which is less than 1 %. This was likely due to the low heating temperature used making the temperature gradient across the height as insignificant. More experiments are currently being carried out to achieve high drying uniformity vertically and horizontally.
