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Show jet impin~e~ent heat transfer has investigated premixed flames , but very few have measured the local heat transfer charactenstlcs. 4.~.2.4 Reduced Particulates. Particulate emissions in soda lime glass (container and flat glasses) are the result of usmg sulfates. in the bath as a melting and refining aid. The SOx content of glass being recycled varies by source ~d type. ~s higher levels of recycled glass are reached, some particulate control problems may occur. Alt~mahve. matenals or furnace designs might reduce or eliminate particulates, thereby lowering the cost of add-on ca~Ita.1 eqwpment. Combustion research would relate to the conversion of S02 gas to sulfate particulates, altering emiSSIon control strategies. . 4.5.2.5 . Fo~ming!Tempering Optimization. Improvements will be necessary in furnace design and operaho~ t~ achIeve mcreased efficiency. The fonning and tempering of flat glass in gas hearth processing are far from opturuzed. The glass is heated with radiant combustion cups. There is little or no lrnowledge about spectral ~esponse. or effects on heat flux distribution (such as height, flow rate fuel/air ratio, etc.) for the individual cups, and no informahon on heat transfer with arrays of combustion cups. Unlike metals, glass is not opaque at wavelengths below 4.5 X 1 0~6 meters . .It may be feasible to optimize the spectral characteristics of burners for heating the glass uniformly and effiCIently, which relates to major quality issues for fonning and stress levels. . 4.5.2.6 Optimizing Combustion and Process Control. The melter's combustion process consumes a large pO~IO~ o~the total facility's energy. Although significant progress in control has been made in tills area, design optunizahon requires better understanding of the process fundamentals . Furnace design features that affect flame development (fuel and air mixing) and optimize heat transfer to the melt need to be better understood. Changes in design involve significant risks, especially when air emission control is also required. Research is needed to enhance productivity and quality through improvements in process control and equipment perfonnance. Develop combustion process control with real-time capabilities, heat flux (transfer) sensors, and CEMSs (continuous emission monitoring systems). Develop and apply fuzzy logic and neural network control strategies to improve productivity, quality, and output. 4.5.2.7 Oxy-Fuel Evolution. A significant trend is developing to convert to furnaces that use nearly 100% oxygen combustion to reduce NOx production and particulate emissions. Since the application of this teclmology is relatively new, process optimization is needed. Operating economics are higher than conventional furnaces because of the cost of o""ygen. Some new methods of on-site generation have been developed. Waste heat recovery has not been applied to the illgh-temperature exhaust gases from oxy-fuel firing (the exhaust contains up to one-third of the heat input). Required add-on equipment for particulate and SOx emissions should be integrated into waste heat recovery schemes. 4.5.2.8 Process Monitoring and Control Instrumentation. Infonnation from advanced instrumentation can be used to control combustion parameters and improve process control. Strategies to further improve the manufacturing of glass products require obtaining representative and reliable data from yet to be developed sensors within key areas of the processes. Thermocouples that are cost efTective to use in relative large numbers (nonprecious metal coated) are needed to provide multiple molten glass temper~ture measurel!1ents in t.he distributo.r and forehearth areas, where controlled temperature conditioning using combustIOn processes IS recognIzed as defiCient. Noncontact temperature measurement sensors should be developed to detenlline glass temperature profiles in the furnace and throughout the glass fabrication processes. These sensors must detect temperature rapidly, so the information can be used in control processes. More reliable and cost-effective sensors (for temperature and gaseous species) should be developed that can be used to monitor the molten glass and combustion space, so that relatively large arrays can be used to provide infonnation to improve process control. Also needed are lower cost, high-reliability air emission monitoring equipment that can detect SO"" NOx, CO, 0 2' and particulates. 16 |