OCR Text |
Show 4.5.2.9 Waste Heat Recovery. Further expenditures for more insulation or larger regenerator systems are not cost effective for today's modern furnaces . Significant additional waste heat recovery may be possible by preheating the cullet and batch raw materials. Although heat recovery is not usually considered part of the combustion program, preheating cullet and batch reduces required from the combustion process. 4.5.2.10 Process Modcling. There is a strong need for improved capabilities to model and control the complex process of glass melting and fabrication to provide consistency and high quality at high production rates. All-electric furnaces are more them1ally efficient than fossil-fired furnaces . They are limited in size (under 300 tons of glass per day) and because of the high cost of electricity their energy cost per ton of glass is higher than fossil furnaces. As a result, use of electric heating for container production is generally limited to partially replace (boost) fossil fuels . Electric boosting increases furnace productivity, improves glass quality, and minimizes furnace emissions. The glass industry has generally relied on operating experience with actual equipment for developing new and improved furnace designs using electric boost. As a result, improvements have been slow to evolve. Development of improved furnace models would increase understanding of the melting process and the influence of electric boost. Both physical and mathematical models should be reviewed to detem1ine their applicability to the type of glass melted, glass products made, and furnace type and geometry. Detailed computer models should then be developed to aid in furnace design and process optimization. 4.5.3 Furnace Computer Modcling The glass industry necds integrated furnace models that can calculate transient thennal and chemical behavior and can be used to develop methods to optimize energy use and reduce air emissions. Models should link the dynamics of combustion, heat transfer, glass flow and temperature, and furnace throughput. Models should be developed to (a) optimize fuel combustion and heat release parameters based on furnace design factors, (b) calculate glass melting and temperature conditioning (distribution), (c) include improved combustion models for prediction of pollutant production (SOx, NOx, and particulates) and the eITects of gaseous bubbles in the melt, and (d) improve understanding of glass chemistry, including chemical kinetics of batch melting and reactions in glass, chemical equilibrium and solubility data, and chemical kinetics influenced by variables in the combustion environment. Additionally, computer modeling of oxy-fuel melting in large float glass furnaces should be developed. Work needs to be continued to correlate numerical data and operating parameters and use them for development of expert control systems, including systems for melting, processing, and emissions. 4.5.4 Equipment Optimize furnace designs to reduce NOx, SO;o and particulate emissions. This may include improved burners ' and means of reducing the particulates entrained in the combustion products. Develop equipment and techniques for promoting enhanced heat transfer. Develop equipment that will improve energy recovery from the melter by preheating batch materials and cullet. The design should include the capability to install equipment to remove NOx, SOx, and particulate emissions. 4.6 Aluminum Industry An evaluation of research needs for the altm1inum industry was made using several sources. These sources have included past evaluations of industrial research needs (Peru1er 1994, Chace 1989, Choce 1988). Another source was a survey of aluminum industry research needs recently conducted by Energy and Environmental Research Corporation (EER). Results of this survey are sunmlarized in this section. The survey included not only aluminum company representatives (Kaiser AlwuinuI11, Gas Research Institute) but also companies that depend on and are knowledgeable of alwuinum industry research needs. These included aluminum furnace and burner equipment manufacturers (KYS, Hauck, Lindberg, Surface Combustion, Maxon, CEC, and MPH Ind.), and natural gas and merchant gas companies (Southern California Gas Co., Air Products, and British Oxygen Company). 17 |