Physicochemical and hygroscopic properties of charcoals produced from residues of two tropical woods from Cameroon

Abstract

ABSTRACT The aim of this study was to determine the physicochemical and hygroscopic properties of charcoals from Doussie (Afzelia africana) and Okan (Cylicodiscuis gabunensis), produced from residues of two tropical woods from Cameroon. The properties determined for these charcoals included physical (moisture content, basic density, high heating value) chemical (proximate analysis, ultimate analysis, FT-IR analysis), and hygroscopic (absorption and sorption) properties. Our results show that these properties differ between the two woods. Higher values were obtained with Okan, except for the fixed carbon content. A higher diffusion coefficient on water uptake was also observed with charcoal from Okan (3.25 × 10−8 ± 0.22 m2/s) compared to charcoal from Doussie (2.42 × 10−8 ± 0.21 m2/s). The highest equilibrium moisture contents in sorption are obtained with charcoal from Okan. Our results also reveal a relationship between hygroscopic behavior and charcoals properties. It was found theoretically that an increase of initial moisture content of charcoals about 19% caused a decrease in their initial fixed carbon content about 2% and in their initial high heating value about 2.5%. The charcoals studied are of good quality and meet the recommended standards for domestic use even in humid areas.