Spatial Distribution of Temperature and Moisture in Grain Bin and Grain Bin Size Effect on STR Dryer Performance in Bangladesh

Abstract

Technical feasibility study of low cost mechanical batch dryer (STR) was carried out at the Department of Farm Power and Machinery, Bangladesh Agricultural University, Mymensingh during 30 April to 05 May, 2015 in order to investigate effectiveness of using at farmers’ level as alternative to sun drying. The detail technical parameters e.g., spatial distribution of temperature and moisture content, drying rate, drying capacity, drying efficiency and germination test related to paddy drying were analyzed. Three treatments based on grain bin size i.e. 300, 400 and 450 kg of paddy as S300, S400 and S450, respectively, were selected and three replications of each treatment were conducted for the STR dryer performance study. The temperature profile of STR dryer proved that hot air uniformly distributed throughout the dryer, and the paddy dried uniformly and reached at desired moisture level (less than 12%) in between three to five hours. The drying rate i.e. moisture removal rates of the STR dryer were 11.3, 12.2 and 15 kg/hr for the treatments of S300, S400 and S450, respectively. The drying capacities of the STR dryer were 75.0, 88.9 and 121.6 kg/hr/batch for treatments of S300, S400 and S450, respectively. The drying efficiency (73.1%) of treatment S450 was found highest than that of others due to higher energy use efficiency. The dryer performance was also found satisfactory in terms of seed quality.