PERFORMANCE EVALUATION OF CROSS-FLOW RICE DRYERS
Munir Ahmad*, Asif Ali Mirani**, Hafiz Sultan Mahmood**, Tanveer Ahmad** and Muhammad Azhar Saeed**
A considerable amount of rice grains is wasted every year in Pakistan because of unavailability of postharvest drying and processing technologies. About 70% of the rice produced in the country is dried through sun heat. which is one of the major causes of reducing head rice recovery during the milling operation. Recently, cross-flow rice dryers have been adopted in the rice milling industry of the country. The heat source of these cross-flow dryers can be a gas or rice husk. This study focussed on the performance evaluation of cross-flow rice dryers with both gas and rice husk heat sources. The experimental results indicated that drying air temperature of the gas-fired and rice husk-fired dryers was 54° and 66°C, respectively. However, the average air flow rate was 6.24 and 3 -1 2.60 m s of gas-fired and rice husk-fired cross-flow dryers, respectively. -1 The drying rate of gas-fired dryer was 2.0 percentage point h , whereas the -1 drying rate of rice husk-fired dryer was 1.0 percentage point h . The drying costs of gas-fired and rice husk-fired dryers were about Rs. 0.21 and 0.16 -1 kg . The overall performance of the gas-fired dryer was satisfactory, while that of the rice husk-fired dryer can be improved by incorporating an appropriate heat exchanger.