Development of a Cross-Flow Fish Smoking Kiln Fired by Biomass Material

Traditional smoking of fish in Nigeria is often carried out in open and unsanitary environment. In addition, the current process does not result in uniformly smoked fish and uses wood （an increasingly scarce material） as heat source. The fish smoking kiln designed and fabricated in this study addresses these problems. The kiln （700 × 800 × 1,500 mm） is made of stainless steel on the inside and mild steel on the outside with glass fiber insulation separating the inside and outside covers. The sample to be smoked is totally enclosed by the kiln with a latchable door provided at one of the sides for placing of samples to be smoked. In addition, the kiln was designed to use waste biomass resource as fuels （sawdust and/or maizecob）. Bonga fish （Ethmalosafimbriata） and African catfish （Clarias gariepinus） were used as test samples for the kiln. The temperature of the chamber increased to about 120 ℃ to 160 ℃ when fueled with sawdust and about 150 ℃ to 200 ℃ for maizecob. The total heat transfer resistance through the kiln walls was determined to be 1.0 ℃/W. About 6-8 h was required to smoke-dry 16 kg of fish samples from initial moisture content of 75% to about 25% or 20% moisture level.