Characteristics of rice husk biochar briquettes with municipal solid waste cassava, sweet potato and matooke peelings as binders

Rice husks are not readily biodegradable making their disposal challenging due to the common disposal method of open burning which has negative environmental effects. Additionally, banana, sweet potato and cassava peelings form a large percentage of organic municipal solid waste. Therefore, this study developed rice husk biochar briquettes with organic municipal peelings waste as binders. Rice husks biochar was formed via carbonization processes in a step-down kiln at temperatures ranging between 400 and 500 °C. Organic binders were mixed with the rice husk biochar at different ratios of 10% and 15% before being compacted at a pressure ≤ 7 MPa into briquettes. Thermogravimetric results showed that the developed briquettes had high ash contents ranging from 44% to 47%. Rice husk biochar briquettes with the highest particle density were observed for briquettes with 15% cassava peel binder at 427.1 kg/m³. The highest HHV and maximum attainable flame temperature of 21.75 MJ/kg and 828.7 °C were obtained for rice husk biochar briquettes with 15% matooke peeling organic binder. For all rice husk biochar briquettes, increasing the organic peeling binder had a positive impact of reducing the ash content, while at the same time increasing the peak temperatures, thus contributing to their enhanced thermal stability.