Carbonization characteristics of juvenile woods from some tropical trees planted in Indonesia

The objective of this study was to evaluate the characteristics of charcoals from juvenile woods of albizia (Paraserianthes falcataria), gmelina (Gmelina arborea), rnindi (Melia azedarach), and mangium (Acacia mangium). Carbonization was performed at 400, 600, and 800°C for 10 min with a heating rate of 6°C/min. The physical, bioenergetic, and chemical properties were evaluated. Maximum char yield was obtained at 400°C and the increase of carbonization temperature resulted in a decrease of char yield. At the same carbonization temperature, char yield was higher in wood with greater initial density, i.e. ordered from the highest to the lowest: mangium, mindi, gmelina, and albizia. The heating values in all woods increased after carbonization, with maximum values at 600°C. Maximum energy densification ratio and energy yield were obtained at carbonization temperature of 600°C and 400°C, respectively. Char yield of 23.62-39.03%, heating value of 25.16-33.85 kJ/g, energy densification ratio of 1.45-1.72, energy yield of 39.09-60.10%, ash content of 0.80-3.94%, volatile matter of 14.61-38.69%, and fixed carbon of 58.58- 83.27% were obtained in all charcoals from juvenile woods and were comparable with those of mature woods, showing suitability for the production of charcoal fuel.