Performance Assessment Of Local Biomass Powered Cereal Drier Used By Small-Scale Kenyan Farmers

Abstract Recent studies have revealed that drying maize using biomass driers increase the quality of grains delays insect infestation mold and aflatoxin contamination in relation to direct sunlight drying. Most importantly biomass drying takes shorter time. It is therefore important to undertake performance of these driers to investigate the possibility of empirical control of such systems in remote areas. In this paper we present results of thermal performance of typical biomass-powered drier batch type. The results show that under natural convection temperature behavior within the drying chamber is unpredictable. However the use of exhaust fan forced convection gives predictable temperature distribution within the drying chamber. For burner shutter open at 50 and using maize cob as the fuel for forced convection the drying chamber attained a maximum temperature of 9326730C after 28 minutes and minimum temperature of 6926730C after 37 minutes in the lower tray tray 1. For burner shutter open at 100 the drying chamber attained a maximum temperature of 9126730C after 41 minutes and minimum temperature of 6726730C in tray 1. With burner 50 open tray 2 attained a maximum temperature of 6226730C after 30 minutes and minimum temperature of 5626730C after 40 minutes. With the burner 100 open tray 2 attained a maximum temperature of 6126730C after 39 minutes and minimum temperature of 5226730C after 52 minutes. From these results the optimal operating conditions of the burner operation were achieved when the shutter was open at 50. It took 76 minutes to dry 5kg of maize with about 0.8kg including dampness from rains moisture content in tray 1. It took 140 minutes to dry the same quantity and moisture content of maize in tray 2. These results show that it is possible to control empirically biomass cereal maize driers.