DEVELOPMENT OF A PLANTAIN DRYER USING CHARCOAL AND SAWDUST BRIQUETTE AS FUELS

Abstract

A biomass fired dryer using charcoal and sawdust briquettes as fuels is designed and produced by this study, to improve plantain shelf life, make it available all the year round, minimize postharvest losses, regulate unattractive low commodity pricing during peak harvest season, enhance productivity and add value to commodity. It consists of a heating chamber with integrated ash tray, drying chamber and two drying trays, spaced 130 mm apart. Warm air circulates in the drying chamber by natural draught, while the air for fuel combustion is by forced convection. A batch size of (2 and 4 kg) of plantain chips were dried at temperatures of 80 and, 100°C in three replicating experiments using 0.150 kg of the selected fuels independently. At an ambient temperature of 30.4°C and relative humidity (RH) of 83.6% charcoal and sawdust briquette fuels attained a mean temperature () of (140 and 134), with a burnout time () of (240.6 and 237.7) respectively, under no load. The average drying time () for sliced plantain chips was 120 minutes for 2 kg at 80 and 150 min for 4 kg at 100°C respectively for both fuels, as against open air sun drying, that could take days to accomplish due to unpredictable weather conditions. An average drying rate () of 0.0059 kg/min ( 0.9338) and 0.2082 kg/min ( 0.909) was achieved on the drier with charcoal (Ch) as fuel, while; 0.0058 kg/min ( 0.9322) and 0.2111 kg/min ( 0.9245) was obtained with sawdust briquette (Cs) as fuel at 80 and 100 drying temperatures respectively. The moisture content (MC) of the chips also reduced from 61% to (11.8 MC 11.6%) and (7 MC 6%) respectively, at 80°C and 100°C drying temperatures for both fuels. The proximate analysis of the dried chips indicates a decrease in its protein content with corresponding increase in crude fiber and ash content across temperatures, yet without total loss of nutrients. The dryer successfully utilized the selected fuels for plantain drying and could serve as an effective tool in drying other farm produce.