DURABILITY AND RELAXATION OF SAWDUST AND WHEAT-STRAW BRIQUETTES AS POSSIBLE FUELS FOR KENYA

Densification of agricultural residues and wood waste into fuel briquettes can provide a relatively high-quality alternative source of fuel, especially where solid woodfuel resources are scarce. The objective of this study was to determine the possibility of producing durable briquettes from wheat straw and sawdust as fuel for Kenyan households and small-scale industries. These consumers are burning an increasing amount of these materials, which in their raw form are poor quality fuels. Briquette length expansion at specific time intervals was determined over a 1-week period. The moisture content and durability of these briquettes were measured after a storage period of 2 weeks at approximately 20 degrees C and 50% relative humidity. Sawdust and shavings briquettes were the most durable and exhibited the least degree of length expansion. Wheat-straw briquettes were the least durable and expanded most. However, blending straw with sawdust improved this durability considerably. There appears to be a direct relationship between length expansion and the durability rating of the briquettes. All the briquettes had relatively low moisture content. Briquettes can be manufactured without a binder but with poor durability in the case of straw.