Designing, Realisation and Testing of Combined Dryer-Smokehouse/Cow Dung Based Biogas Production Unit Module in Cameroon

Abstract

This article deals with the setting up of a module combining a biogas production unit and a fish dryer-smokehouse. The prototype was designed at the Thermal and Environmental Laboratory (LATE) of the University of Douala, and then experimented during 66 days. The dryer-smokehouse bears a drying or smoking compartment of volume 0.162m3 partitioned with three perforated grids separating each other by 20cm. On the back part of the drying compartment is mounted a fan which will assure the mixing of the dying air. The combustion compartment of 0.4m3 locks up the oven which produces heat from the combustion of biogas, regulating organs and air entries. The biogas produced from cow dung serves as fuel to the dryer-smokehouse. The digester used is a batch reactor loaded one time with 150 kgs of cow dung diluted at 45%. The biogas was measured by a liquid displacement method. Experimentations show that the cumulated biogas production is of about 9.13m3 in 66 days. The average drying time of 4 kgs of fish (salmo salar) was 8 hours with our combined module and 7 hours with other traditional dryers. The dried fishes are unblemished compare to that dried by traditional biomass dryers. The designed prototype with an overall efficiency of 1.7 kg of dried fish/ kg of cow dung input is cheaper (€ 600) and ecological, therefore could be a green alternative to traditional biomass dryers.