Quality assessment of curupau charcoal (Anadenanthera colubrina), from logs of smaller diameters

Abstract

In Bolivia, charcoal is primarily directed towards industrial activities such as steelmaking and domestic consumption for culinary purposes. The market's preferred species for charcoal production is curupaú (Andeanthera colubrina), which exhibits rapid growth in its early stages and possesses high calorific value, making it suitable for management in forest plantations. However, there is a lack of information regarding the minimum diameter suitable for charcoal production. The aim of this study was to assess the feasibility of producing commercially viable charcoal from thin diameter logs. To achieve this, a randomized design was implemented with five treatments (6-8, 8-10, 10-12, 12-14, and 14-16 cm) based on log diameter. The material was sourced from the municipality of Porongo, and carbonization was conducted in a medium orange-type furnace located in the municipality of El Torno. Physicochemical analyses were performed at the laboratories of the Forestry Engineering Program at the Universidad Autónoma Gabriel René Moreno in Santa Cruz de la Sierra, Bolivia, following the ASTM D 1762-84 standard. The results indicated that the chemical properties of the charcoal exhibited statistically significant differences across the various diameters tested, with the diameter class of 14-16 cm achieving the highest quality levels in terms of moisture content, volatile matter, ash, fixed carbon, and calorific value. Furthermore, the diameter of the log used had a directly proportional influence on the chemical properties concerning fixed carbon content and calorific value, while the ash and volatile matter content were inversely proportional to the diameter. No correlation was found between moisture content and diameter. The highest quality charcoal was obtained from the diameter class '14-16 cm', as it demonstrated an acceptable fixed carbon content, in contrast to the smaller diameter logs, which exhibited low fixed carbon content and high ash content.