Selection of appropriate clay for furnace lining in a pyrolysis process

The suitability of some local clay deposits in Ekiti State, for lining the furnace to be used to degrade woody biomass to fuel and chemical products was investigated. Four major sites in Ekiti State renowned for abundant clay deposits were selected, namely; Ikere Ekiti, Fagbohun Ekiti, Ishan Ekiti and Ara Ekiti. The clay samples were crushed, milled (pulverised) and sieved to produce very fine grains of less than 250 µm particle size distribution for all samples. They were then tested for shrinkage, bulk density, Load on ignition (LOI), cold compression strength, apparent porosity, and thermal shock resistance. Also, their mineralogical composition and fusion temperatures were examined. The densities of the clays were found to be related to their mineralogical composition as shown: Ikere Ekiti clay was found to be less dense, contains more porosity, and possesses low iron content and higher refractoriness with fusion temperature above 1500 °C. Fagbohun clay is also suitable for medium thermal application in furnaces, kilns and stoves, while the rest could be beneficiated to improve on their insulating properties. The kaolin deposit at Ikere Ekiti was found to be the best material suitable for the lining of the furnace for the pyrolysis process as the expected furnace temperature is about 1400 °C.