Comparative analysis of CO2/SO2 emissions of Khaya ivorensis A.Chev. and Terminalia superba Engl. & Diels wood waste using ultimate analysis techniques

Abstract

The increasing dependence on wood residues as a sustainable biomass energy source highlights the need for precise evaluation of their combustion-related pollutants to advance environmentally responsible energy solutions. This research conducts a comparative analysis of carbon dioxide (CO2) and sulfur dioxide (SO2) emissions from two tropical hardwood wastes - Mahogany (Khaya ivorensis) and Afara (Terminalia superba) - through ultimate analysis methods. Samples of these wood wastes were gathered from sawmill disposal sites in Asaba, Nigeria, and examined using X-Ray fluorescence (XRF) spectroscopy to identify their elemental makeup. The analysis showed carbon levels of 47.08% in K. ivorensis and 45.49% in T. superba, with hydrogen at 4.76% and 4.59%, respectively. Sulfur concentrations were particularly minimal, recorded at 0.10% for Mahogany and 0.08% for Afara. Calculations based on stoichiometric combustion indicated CO2 emission rates of 18.795% (wet basis) and 21.214% (dry basis) for Mahogany, while Afara yielded 19.16% (wet) and 22.50% (dry). SO2 emissions remained extremely low across both wood types, falling between 0.010% and 0.017% on wet and dry bases.These findings confirm that both hardwood residues possess desirable combustion qualities, including very limited SO2 output, positioning them as environmentally preferable options compared to conventional fossil fuels. While Afara generated marginally higher CO2 levels, both materials hold considerable promise as viable biomass resources for energy generation across Nigeria and similar tropical areas. The study delivers valuable insights for predicting emissions and encourages the productive reuse of waste from the timber sector.