Characteristics of composite briquettes produced from carbonized banana peels and waste glass

Abstract

Briquettes made from carbonized agricultural residues present sustainable material alternatives to wood charcoal and firewood for commercial and industrial applications. However, these briquettes are plagued by property weaknesses including low drop strength and thermal efficiency. Therefore, this study focuses on enhancing the physical, mechanical and thermal properties of composite briquettes produced from carbonized banana peels and waste glass. Composite briquettes comprised of banana peels biochar and waste glass powder (0%, 5%, 10%, 20%, 30%, 40%, and 50%) were developed, characterized, and evaluated using thermo-gravimetric analysis and bomb calorimetry to determine thermo-physical properties and higher heating values, respectively. The thermal efficiency and emissions (CO, CO2, and PM2.5) were assessed using the water boiling test and an emissions monitoring system. Proximate analysis revealed that moisture content, volatile matter, fixed carbon, and ash content of the developed briquettes ranged from 2.5 to 9.7%, 19.2 to 37.2%, 28.7 to 55.6%, and 7.2 to 44.9%, respectively. Drop strength for the briquettes was 84% without waste glass in the composite, increasing to 94–98% with waste glass included in the composite matrix. Higher heating values ranged from 20.1 to 35.8 MJ/kg. Thermal efficiency rose from 22% with no waste glass powder to 40% with 50% waste glass powder addition, while CO and CO2 emissions decreased from 41 to 11 ppm; and 50 to 15 ppm, respectively. PM2.5 remained constant across all banana peel biochar waste glass composites. Notably, even a modest 10% waste glass composition significantly improved drop strength and thermal efficiency, but higher waste glass percentages correlated with elevated ash values and reduced higher heating values. Therefore, the developed composite briquettes can be used in commercial and industrial applications including in some industrial boilers.