Production and Optimization of Briquettes from Sawdust Bagasse blends Using Thermoplastic Waste as a Binder

Abstract

he rising need for sustainable, affordable sources of energy has encouraged interest in converting agricultural residues and waste plastics into solid biofuels. This study was conducted to produce and optimize sawdust bagasse blends briquettes. The briquettes were produced using thermoplastic waste, specifically HDPE, as a binder at proportions ranging from 5% to 25%. The bagasse and sawdust were dried, ground, and sieved to a particle size of less than 3 mm, then mixed with softened HDPE. The effects of compaction pressure (5–15 MPa), binder content (5–25%), andsawdust-to-bagasse ratio (25–75%) on briquette density, compressive strength, and key combustion properties, including calorific value, moisture content, ash content, volatile matter, and fixed carbon were evaluated. The optimum parameters obtained from the model were a compaction pressure of 15 MPa, an HDPE binder content of 16.34%, and a sawdust proportion of 51.49%, resulting in a density of 0.9145 g/cm³ and a compressive strength of 2.968 MPa, which provide sufficient mechanical integrity for handling and use. Proximate analysis showed low moisture (5.21%) and ash (3.46%) contents, while ultimate analysis revealed high carbon (53.85%), moderate hydrogen (6.03%), and oxygen (39.97% by difference), with very low nsulfur (0.017%) levels indicating low potential for NOx and SOx emissions during combustion. The optimized briquettes achieved a calorific value of 4107 kcal/kg, reflecting a balance favoring enhanced mechanical durability over the study's maximum observed value of 5061 kcal/kg under other conditions. In conclusion, the optimized briquettes produced from sawdust, bagasse, and HDPE binder show satisfactory mechanical integrity, good fuel characteristics, and low environmental impact, indicating their potential as a sustainable alternative for energy generation while supporting effective management of agricultural and plastic waste.