OPTIMIZING LOW MOMENTUM OXY-FUEL BURNER PERFORMANCE IN GLASS FURNACES TO MINIMIZE FURNACE EMISSIONS AND ALKALI VOLATILIZATION

摘要

Glass manufacturers in the U.S. and EU are facing increasing pressure to reduce NOx and paniculate emissions from glass furnaces, and to comply with new, lower emissions limits. To meet these ever-tightening limits, glass manufacturers have the choice to install oxy-fuel combustion, which is widely known to produce very low NOx emissions. However, depending on the type of oxy-fuel burners installed in the furnace, the paniculate emissions from the furnace and the refractory crown corrosion resulting from increased alkali vapor concentration in the furnace may be excessive. The desire to reduce NOx and paniculate emissions, and to avoid rapid crown deterioration have led to the development of low momentum oxy-fuel burners for glass furnaces. Low momentum burners have been used in oxy-fuel furnaces since the late 1990s. However, commercial experience with these burners shows that depending on the burner design and placement in the furnace, emissions and performance are significantly influenced. To optimize the operation of Praxair's low momentum DOC-WFB burners in oxy-fuel container glass furnaces, a Computational Fluid Dynamics (CFD) model was developed using a commercial glass furnace CFD software package to explore the effects of burner design and placement in the furnace on NOx emissions and alkali volatilization. Our results show that the burner design and elevation of the burner in the furnace, relative to the glass melt, play very important roles in reducing NOx emissions and alkali volatilization. The results show that furnace NOx emissions and alkali volatilization can be reduced by about 30 to 45%, respectively, when the low momentum burner elevation above the glass is optimized. Field measurements of the total particulate emissions (PM_(10)) from two oxy-fuel container furnaces fitted with Praxair's low momentum burners measured using EPA Method 5 corroborated this study and showed about a 30% reduction of total paniculate emissions for the furnace with higher elevated burners, compared to the furnace with burners placed directly on the tuckstone. In both cases, the NOx emissions remained below 1 lb/ton.