Performance of a biofuelled detachable fish smoking kiln

Abstract

The most widely employed traditional method of processing and preserving fish for human consumption in the third world are smoking and drying. However, the traditional smoking and drying methods restrict the cross border trade of preserved fish due to the associated poor quality of the products, low capacity and poor energy efficiency. A detachable smoking kiln that uses solid biofuel as energy source and enables processing of fish into good quality and highly competitive shelf stable smoked dried fish and fish oil was developed. It consists of insulated walls, segmented compartments and a solar powered fan that circulates heat and smoke. The fan is powered by solar photo voltaic (PV) cell and/or DC cell. The equipment is detachable enhancing its portability feature. It has an overall ground size of 95 cm × 90 cm; the height excluding hood and chimney, is 136 cm and the gross weight is 211 kg. The no-load temperature profiling of the equipment showed an even distribution of heat within the smoke drying chamber. Performance evaluation conducted on the equipment using fresh water catfish (Clarias gariepinus) (average live weight of 350 g ± 50 g per piece) as test organism showed that the kiln has a batch capacity for processing 50 kg live weight (average moisture content, 72% w. b.) of Clarias gariepinus to smoked dried fish (average moisture content, 5.5% w.b.) in 10 h when operated at 110oC ± 10oC. The observed batch capacity agrees with the design calculation. About 57% of the total oil content of the test fish samples was collected using the oil collecting system of the equipment. The equipment reduced frequent rotation of fish by operator and the associated drudgery during smoking operation. The smoked fish were uniformly dried.