Abstract:

Harnessing agricultural residues for clean thermal energy requires more than material substitution, it demands precision engineering. This work introduces a technology-driven pathway for briquette innovation by integrating advanced material selection with statistical process optimization to develop high-performance solid biofuels for domestic heating. Torrefied coconut shell (CNS) and rice husk (RHK) were blended with 10 wt% molasses and optimized using Response Surface Methodology (RSM) via Design-Expert® (v13.05) to assess the effects of feed composition and dwelling time on compressive strength and shatter resistance. A key technological breakthrough was identified: CNS functions not only as a raw component but as a natural reinforcement medium, exhibiting self-bonding capability due to its high lignin and carbon content. This intrinsic binding action minimizes reliance on external binders and enhances production efficiency. The optimised formulation (100:0 CNS:RHK at 202 g) delivered superior mechanical performance of 3.63 MPa compressive strength and 95.2% shatter resistance with strong statistical reliability (R² = 0.96). Beyond material performance, the study establishes a scalable framework in which statistical modeling replaces traditional trial and error fabrication, enabling predictable durability, improved combustion stability, and seamless integration with low-emission stove technologies. By transforming low value biomass into structurally optimized, energy efficient fuels, this research advances clean thermal technology development and accelerates the transition toward resilient, renewable household energy systems.