K. Charith Kumar, G. Rajender, M. Bharath Kumar, M. Madhusudhan, P. Harichandraprasad, S. Shreya Reddy and Sowmya Joshi
Abstract
This study investigates the production and performance optimization of biochar briquettes derived from Neem (Azadirachta indica) residues as a sustainable alternative to open-field burning. Using a horizontal mild steel charring kiln and a 50 kg/h capacity briquetting machine, raw biomass was converted into high density fuel, increasing bulk density from 40â200 kg/m³ to 600â1200 kg/m³. The research evaluated the interplay between two binders (Cattle Dung and Calcium Hydroxide) and two initial moisture levels (38.13% and 10.83%). Mechanical and thermal analyses revealed that cattle dung is the superior binding agent, achieving a peak compressive strength of 63.259 N and a maximum burning capacity of 421.02 kcal/h at a 10.83% moisture level. While calcium hydroxide produced heavier briquettes, the fibrous, porous structure of the dung-based B40D60 composition (40% biochar, 60% dung) ensured significantly better airflow and higher heat delivery for domestic use. Reducing biochar moisture to approximately 10% was identified as a critical parameter for ensuring structural integrity and combustion efficiency. The study concludes that this localized, eco-friendly technology provides a viable waste-to-energy route that supports rural employment while offering a durable, high-performance fuel for domestic slow-cooking applications.