Effect of carbonization moisture on charcoal quality and yield of selected bamboo species grown in Uganda

Abstract

Following the ban on charcoal production and trade in Northern Uganda due to excessive forest degradation, there has been a growing need for alternative fuel sources. One proposed solution is the establishment of energy woodlots with fast-growing species like bamboo. However, there is insufficient information on bamboo's potential for producing marketable charcoal. This study investigated the potential of bamboo as a charcoal source and examined the effect of carbonization moisture on charcoal yield and the physicochemical properties of bamboo species grown in Uganda, specifically Bambusa polymorpha and Dendrocalamus asper. Charcoal was produced using a retort kiln, with 30 kg batches of bamboo carbonized after determining their moisture content. The resulting charcoal samples were analyzed for; calorific value, ash content, fixed carbon content, water absorption, and density.The results showed that Bambusa polymorpha consistently yielded 23% across samples, indicating stable production, whereas Dendrocalamus asper had a variable yield (21% - 28%) with a mean of 23.63%. Bambusa polymorpha had lower ash content (0.5% - 5%), calorific values ranging from 21,510 kJ/kg to 26,800 kJ/kg, and moderate densities (0.28 g/cm³ - 0.31 g/cm³). Conversely, Dendrocalamus asper displayed wider ash content variability (5% - 15%), similar calorific values (22,370 kJ/kg - 26,010 kJ/kg), and slightly higher densities (0.31 g/cm³ - 0.34 g/cm³). Water absorption was higher in Bambusa polymorpha (53.49% - 54.32% over dry weight) compared to Dendrocalamus asper (26.7% - 46.6%), suggesting differences in moisture retention capacities.In conclusion, the study demonstrated that bamboo, particularly Bambusa polymorpha and Dendrocalamus asper, shows strong potential as an alternative source of sustainable charcoal in Uganda. Carbonization moisture content was found to significantly influence yield and physicochemical properties, impacting bamboo charcoal's overall marketability. It is recommended that further research focuses on optimizing carbonization techniques to enhance yield and energy efficiency, as well as expanding bamboo woodlots to meet growing energy demands while reducing deforestation pressures.