Thermal performance and flue gas emission analysis of biomass combustion chamber for small-scale brick production

• Biomass chamber reached 1140 °C, ensuring optimal brick firing temperature. • Achieved high combustion efficiency of 97 % at λ = 1.8 with dry biomass fuel. • Emissions of CO, NOₓ, SO₂, and PM₂.₅ met strict international standards. • Heat transfer peaked at 270 W/m²·K; heat flux reached 320 kW/m². • Tailored design for small-scale kilns offers eco-friendly fuel alternative. The brick manufacturing industry is one of the most energy-intensive sectors and a significant contributor to air pollution, primarily due to its reliance on coal and diesel fuels. This study examines the thermal performance and flue gas emissions of a biomass combustion chamber, specifically designed for small-scale brick production, to address this environmental challenge. The objective is to evaluate combustion efficiency, heat distribution, and pollutant emissions while comparing the system's performance with conventional coal-based systems. The combustion chamber was experimentally tested using real-time data acquisition systems to monitor temperature profiles, heat flux, and emissions of CO, CO₂, NOₓ, SO₂, and particulate matter (PM₂.₅). Results showed that the chamber achieved a peak temperature of 1140 °C, a maximum heat transfer coefficient of 270 W/m²·K, and a heat flux of 320 kW/m². The optimal combustion efficiency reached 97 % at an air-fuel ratio (λ) of 1.8 with biomass moisture content below 10 %. Emission measurements revealed significantly lower values compared to conventional systems, with CO at 85 mg/m³, NOₓ at 45 mg/m³, SO₂ at 8 mg/m³, and PM₂.₅ at 25 mg/m³. These findings demonstrate the system’s compliance with international environmental standards. The novelty of this work lies in its integrated design approach, tailored for small-scale brick kilns, which combines optimised geometry, air staging, and thermal analysis. In conclusion, the study confirms that biomass-based combustion chambers offer a technically viable and environmentally sustainable alternative to fossil-fueled systems in the brick manufacturing sector.