Thermal and chemical characterization of lignocellulosic wastes for energy uses

Two forms of waste lignocellulosic biomass-pine sawdust milling residues from Zimbabwe and Acacia tortilis, an encroacher species from rangelands and urban circles of Botswana-are characterized to evaluate pertinent thermal and chemical properties. Characterization is useful for Acacia tortilis, whose properties have scarcely been studied The ultimate analysis reveals that Pine has a CHNO composition of 45.76%, 5.54%, 0.039% and 48.66% respectively, while the Acacia elemental composition is C (41.47%), H (5.15%), N (1.23%) and O (52.15%). Thermogravimetry results showed that A. tortilis’ ash, fixed carbon and volatiles matter composition was 3.90%, 15.59% and 76.51% respectively on a dry basis; while pine was 0.83%, 20% and 79.16% respectively. The high heating value for Acacia was found to be 17.27 MJ/kg compared to 17.57 MJ/kg for pine. The research establishes that A. tortilis’ fuel properties are comparable to pin. A. tortilis’ high ash content is below critical values.