Design and construction of a biomass tray dryer for cassava mash.

Abstract

Cassava (Manihotesculenta) is an important carbohydrate food source for more than 800million people around the world(FAO,2007). Cassava is a highly perishable root crop which is attributed to its high moisture content. The loss of the high moisture content through respiration and transpiration lead to rapid deterioration which begins within the next 24hours after harvesting. Cassava needs to be dried immediately after harvesting to increase its shelf life. The most commonly used dry erforagroproduceis the tray dryer because of its simple design and capability to dry products at high volume. However, the greatest drawback of the tray dryer is uneven drying leading to non-uniform quality and shows low levels of drying efficiency. The aim of this research was to improve the batch uniformity and the drying efficiency of a tray dryer suitable for small holder farmers. An experiment was carried out where 10 kg of pressed cassava mash were placed at the dryer’s 4trays, that were stacked atopeachother. Moisture content (wet basis) was reduced from 48 to14 % in about 2.5 hours. It was found that a low-cost modification to the dryer chamber of putting guidelines at the inletand increasing the number of air outlets was able to improve heat distribution and increase the uniformity of the mash’s moisture content. The purpose of this study was to design and construct a biomass tray dryer for cassava mash with proper air distribution in the drying chamber so as to achieve even drying in the tray dryer. A biomass energy system in this study was developed and achieved through data collection which involved literature surveys and reviews and internet surfing, designing the system components, constructing the prototype which was tested and the results analyzed.