The number of conversions from air-fossil fuel fired to oxygen-fossil fuel (oxy-fuel) fired glass furnaces increased greatly between 1990 and 2000. This development was driven by the availability of cheaper oxygen production techniques, stricter NOx-emission limits for glass furnaces in some parts of the world, space constraints and energy efficiency requirements. This paper will show experiences and observations in the glass industry with oxy-firing technology since the beginning of the 90s with respect to furnace operation, energy efficiency and emissions, and the changes in glass melt chemistry due to increased water concentrations in the melt. Foaming, firing and emission issues are addressed and are related to the increased water concentration in the furnace atmosphere.
