Enhancing Emission Reduction and Efficiency in Biomass Steam Boilers Through Fgr: Examining Nox Production and Operational Dynamics

As a result of efforts to follow sustainable development trends in thermal energy, the increasing utilization of biomass-fired boilers is notable as an environmentally acceptable alternative to conventional fossil fuel-based designs. However, while more ecologically viable, biomass boilers still emit specific pollutants, with particulate matter (PM), sulfur dioxide (SO2), nitrogen oxides (NOx), and carbon monoxide (CO) being the major concerns. To mitigate these emissions, modern biomass-fired boilers often incorporate Flue Gas Recirculation (FGR). This study examines a 14 MW biomass-fired boiler with a 20% FGR rate. Analysis encompasses three scenarios: two FGR levels and operation without FGR. The research reveals a complex interdependence between emissions reduction through FGR and boiler efficiency. Moreover, findings suggest justified reduction in FGR levels to enhance boiler efficiency. The study presents a comprehensive plan for efficient FGR implementation in biomass-fired boilers while maintaining acceptable efficiency levels. For NOx emissions analysis, combustion simulation software and the Zeldovich method were employed to estimate thermal NOx production.