Future of oxy-fuel glass melting: Oxygen production, energy efficiency, emissions and CO2 neutral glass melting

Over 300 commercial glass melting furnaces have been successfully converted to oxy-fuel firing worldwide since 1991 when the first full oxy-fuel conversion of a large container glass furnace took place. The main benefits of oxy-fuel conversion are fuel reduction, glass quality improvement, emissions reduction (CO2, CO, NOx, SO2, particulates), and productivity improvements. Significant changes in the melting and fining behaviors were observed under oxy-fuel firing. Most furnaces required some batch modifications to optimize the glass fining chemistry and to control foam. Improved oxy-fuel burner and furnace designs have reduced alkali volatilization and silica crown corrosion. Silica crown is expected to last for a full furnace campaign, especially with new no-lime silica bricks. Today most of high-quality specialty glass products such as LCD display glass and fiber glass are melted in oxy-fuel fired glass furnaces. Oxy-fuel conversion of large soda lime glass furnaces, however, has been limited to about sixty container and ten float/flat glass furnaces due to the additional cost of using oxygen. Key factors to improve the economics of oxy-fuel fired such as efficiency of air separation technology and waste heat recovery are reviewed. The potential of using hydrogen and renewable fuels with oxygen to reduce CO2 emissions is also discussed. © 2021 The American Ceramic Society.