Production of Solid Fuel Briquettes from Agricultural and Wood Waste (Saw Dust and Rice Husk)

Abstract

Fibrous agricultural and wood waste materials have been compressed with suitable adhesive into solid fuel briquettes in a compressing machine, which was designed and constructed for this purpose. Nine samples of fibrous waste materials were prepared into different categories:- Category A (100% saw-dust, 100% rice-husk, 50-50% rice-husk/sawdust using starch as adhesive). Category B (100% saw-dust, 100% rice-husk, 50-50% rice-husk/ saw dust using gum arabic as adhesive) and category C (100% saw-dust, 100% rice husk, 50-50% rice-husk/saw dust using bentonite as adhesive). The solid fuel briquettes in category C had the lowest average moisture content of 9.1%, categories A and B solid fuel briquettes had 10.5% and 13.0%, respectively. The results from a water boiling test (WBT), involving comparsion of the burning abilities of the solid fuel briquettes and fire wood of the same quantity (200 grammes) in boiling 1.5 litres of water showed that the solid fuel briquettes bound with each of the three adhesives; bentonite, gum arabic and starch; boiled water within a period of 14 to 22 minutes, while firewood did so within a period of 22 to 27 minutes. The open flame test showed that the solid fuel briquettes bound with starch burnt with bluish yellow flame with little black smoke indicating that the stoichiometric (air-fuel) ratio was almost correct. The solid fuel briquettes bound with gum arabic and bentonite burnt with yellow flame with moderate black smoke., indicating incomplete combustion due to poor air-fuel ratio. The reason for this cannot be ascertained.