Simulation of flame development in a glass furnace with hydrogen enriched natural gas

The glass manufacturing industry is energy demanding and has significant environmental impacts due to the high temperatures required for melting raw materials, resulting in pollutant emissions. With the EU's goal of climate neutrality by 2050, reducing energy consumption and emissions in glass production is a key priority. Integrating some quantities of hydrogen in the fuel mixture can offer a promising solution for decarbonization. While hydrogen is being explored in industries like steel, its potential as a clean fuel for glass furnaces still requires further research. This study focuses on the impact of introducing hydrogen into the fuel mixture for glass furnace combustion. Using an innovative CFD framework that overcomes the limitations of existing models—where combustion is typically treated with oversimplified approaches and the glass tank is solved separately via iterative coupling between domains—this work introduces a fully coupled simulation of both the combustion space and the glass bath within a single computational environment. The reactive flow is resolved using a reduced chemical kinetic mechanism in combination with the EDC (eddy dissipation concept) turbulence–chemistry interaction model, enabling an accurate representation of combustion development. This advanced setup is employed to assess the effect of hydrogen enrichment while maintaining the same overall thermal input power as the natural-gas-only baseline case. The results demonstrate that a 30 % hydrogen addition (by energy) can achieve a substantial reduction in CO2 emissions of nearly 30 % and a decrease in NO emissions of approximately 40 %, highlighting the significant environmental benefits of hydrogen enrichment, while simultaneously introducing serious flame stability challenges that must be carefully managed. This behaviour has been thoroughly analyzed, with particular focus on flame patterns, heat flow distribution and glass surface temperature. To address this challenge, some strategies are proposed to stabilize combustion, restoring stable flame conditions akin to those observed with natural gas. The study aims to explore hydrogen's potential in decarbonizing the glass industry, offering practical solutions for integrating hydrogen into production processes with promising results. This contributes to reducing industrial carbon emissions and supports the transition to a more sustainable energy system.