Glass Tank Furnaces Research Articles

A Glimpse of the Evolutionary Studies on Glass Tank Furnace in Terms of Raw Materials, Melting Process, Refractories, and Energy Efficiency

This paper discusses the raw materials used in ancient glasses. Following a consideration of some archaeological reasons for studying glass, the discussion concentrates on the evidence provided by the chemical analysis of the glass and focuses on glass from later prehistoric Western Europe. Consideration of the major, minor, and trace components of the glass leads to the conclusion that prehistoric glass artisans were able to closely control the addition of small quantities of colorants, opacifiers and clarifiers to the glass melt. Some possible ways of introducing such small quantities of these substances are suggested. Reduction of fuel consumption in glass melting furnaces can cut the cost of production, and tackle the global warming. The paper presents three independent solutions to reduce the fuel consumption in industrial glass melting furnaces. The solutions include air preheating, raw material preheating, and improving the insulation of combustion space refractory. Energy balance equations are derived and used to identify the effects of each solution. The results indicate that the three solutions reduce the fuel consumption by 9.5%, 17%, and 34% respectively. An insight into the refractory usage is shown for different sections of the glass tank furnace.

Recycling of exhausted dust from regenerator of glass furnace in glass batch melting

In soda-lime glass manufacturing, evaporation of volatile compounds from glass melt is the origin of the dust emission from glass tank furnace. The exhausted dust then is deposited on the regenerator and is needed to be removed. Thus, this study focuses on using the dust from melting glass in glass production. The glass batches were prepared from 0 wt% to 10 wt% of the exhausted dust from soda-lime glass production as a substitution of the total raw materials. The analysis of phase and chemical composition of the dust by x-ray powder diffraction (XRD) and x-ray fluorescence technique (XRF) indicated that it consisted mainly sodium sulphate. Thermal analysis (TG/DSC) revealed that the addition of exhausted dust reduced the temperature of the melting reaction of the glass batches. The optimum amount of the exhausted dust, which made it possible to obtain the glass with the lowest number of remaining bubbles, was 2 wt%. From CIE lab and dilatometry results revealed that up to 2 wt% replacement of total raw materials by the exhausted dust in the glass batch did not affect the glass color, thermal expansion coefficient, glass transition temperature and dilatometric softening point of glass samples.

Numerical Simulation of Heat Transfer and Fluid Flow in Glass Tank Furnace after Bubbling

Numerical method to simulate the effect of air bubblers on glass melt flow and heat transfer in glass tank furnace is presented in this paper. The numerical simulation is preformed by using Gambit and Fluent software. Results of numerical simulation for glass melt flow and heat transfer with and without air bubbling technology are compared. The roles of stirring air bubblers installed in different locations played are discussed. The results show that mathematical model established in this paper can better simulate the glass melt circulation and heat transfer in glass tank furance, and air bubbler has a significant effect on glass melt circulation and heat transfer, and the best installation locations should be chosen by calculating in order to make full use of the air bubblers. Air bubbling technology will improve the quality of glass obviously if it is used properly. The results obtained can provide reference for engineering design of glass tank furnaces.

Modeling of Redox Reaction in Glass Melt and Its Effect on Glass Flow

A new mathematical model is developed to solve transport of FeO with an apparent redox reaction coupled with a model of thermal convection in a glass tank furnace. A numerical method is proposed to calculate the distribution of FeO with a non-equilibrium reaction in a flow field. Computer simulation enables prediction of the FeO concentration, thermal conductivity, and optical characteristics. It is apparent that chemical homogeneity is attained by residence time and temperature, and that it is more uniform than the mechanical homogeneity by glass flow.

Method for Evaluating Thermal Convection in Molten Glass Flow in a Glass Tank Furnace

Various computer simulations of molten glass flow have been used for the design, operation and trouble shooting of glass tank furnaces. It is necessary to predict the degree of thermal convection of molten glass, whose viscosity is affected by the major composition of glass and thermal conductivity of which varies with the ferrous oxide (FeO) content. The thermal conductivity decreases as the FeO content increases. Thermal convection is characterized by the Rayleigh number, Ra, and the Prandtl number, Pr. Typically, Ra is expected to be large for a small thermal conductivity, but the actual thermal convection is weaker in this case than when the thermal conductivity is large. To elucidate the underlying convection mechanism, a two-dimensional mathematical flow model is developed in this study. Non dimensional formulation of the governing equations shows that Pr–1 affects the degree of thermal convection. The effective value of Ra, Raeff, is introduced to evaluate the influence of temperature-dependent properties on thermal convection. An evaluation method of thermal convection is proposed and extended to glasses with different thermal conductivities.

Mathematical model of bubble number density in glass tank furnace

There have been innumerable contributions to clarify bubble behaviour in glass melt, where various approaches have been carried out. Experimental results show bubble quality is represented by bubble number density, bubble diameter, and standard deviation of the diameter, which depend on time and temperature. The latest experiment implies growth of bubble is strongly dependent on temperature, and the standard deviation is independent of time and temperature. Not only appeared location but also number density of small bubble (seeds) is of major concern for manufacturers to produce high quality glass. A new mathematical model is developed to predict bubble number density, which quantifies effect of both fining and refining on the density by introducing an exhausting effect of bubbles from upstream of the highest temperature area, i.e. hot spot, and the downstream in melter, i.e. stagnant. Inlet bubble number density with melting down is extrapolated from the published data. Monitored diameter obtained in experiment is applied to calculation. Calculated bubble number density is compared with measured one in an actual flat glass furnace, which makes it clear that the mathematical model is valid to predict order of the density in the glass melt. Numerical simulation gives reasonable suggestion about fining effect.

Mathematical Modeling of Sulfate Fining in a Glass Melting Furnace

In this study, we propose a new mathematical model of dissolved SO3 transport in a glass melting furnace, considering secondary decomposition of sulfate. The calculated concentration of SO3 agrees with measured data near the maximum temperature area, hot spot, in an actual glass tank furnace. The effect of onset temperature of secondary decomposition, the maximum solubility of SO3 and concentration of inlet SO3 on sulfate fining is quantified by simulation.

The trend toward development of tank furnaces in production of sheet glass

The cardinal changes in the design of sheet glass tank furnaces that significantly improve the technical and economic indexes are examined. The most effective technical solutions are the change in the design of the feed pocket, burners, regenerators, and knuckle and equipping them with modern process equipment and highly stable refractories.

4002 流体/温度場/電場連成解析の応用による,ガラス槽窯炉材選定の適正化(F-1 フォーラム「電磁流体解析関連技術」)

Numerical Analyses of Glass Tank Furnace are performed which include direct Joule heating by electricity. Effects of tank refractory and glass on heating distribution, temperature distribution and flow distribution, is investigated. The results indicate that for the case of glass with low electric resistance ZFC refractory, which has superior performance for high temperature corrosion and for glass defects, is suitable. Whereas, the results show the problem of local heating at refractory when ZFC refractory is used for glass with high electric resistance. In case of using ZFCR which has high electric resistance with not less than the same performance as ZFC, the suitable result is found even for the glass with high electric resistance. The Fluid/Temperature/Electricity combined computational analysis makes it possible to select appropriate refractory for various kind of glass composition to be manufactured.

Recent Trends in the Application of Refractories for Glass Tank Furnaces: Part-II: Melter, Crown, Refiner and Feeder

The application of refractories in glass-tank furnaces in the organized sector varies according to the type of end-product, glass composition and the furnace construction design. In Part I of this paper, use of different types of refractories in regenerator chequer system was discussed. In this concluding section (Part II), the refractories generally used in melter, crown, refiner, forehearth and feeder have been presented.The technology and application of refractories in glass furnace have since been developed and improved with the changing glass manufacturing techniques. While there are different types of refractories used for different types of glass furnaces, emphasis has been given to the types of furnaces employed for container and sheet glasses in the organized sector only.

Recent Trends in the Application of Refractories for Glass Tank Furnaces: Part-I: Regenerator Chequer System

The glass tank furnace is one of the main features of the glass industry in the organised sector. Different types of refractories are used in the furnaces, depending upon the glass composition, end-product and the furnace construction design. The application and performance of the right type of refractories not only prolong the compaign life of the furnace but also influence a rapid and homogeneous melting. Selection of refractories for the glass furnace thus becomes of prior importance also from the point of energy conservation and cost effectiveness of the process. In the present paper, the major types of refractories that are being used for the manufacture of glass and glassware utilizing tank furnace with regenerator system have been taken into consideration. The paper is the outcome of an intensive interaction with the glass and refractories manufacturers. Part I deals with the regenerator chequer system.

Improvement on the construction of a float glass tank furnace by physical modeling

The temperature distributions, velocity fields, and the glass current of a tank furnace were investigated by means of physical modeling. Some measures to improve the design of the conditioning zone of a float glass tank are proposed. They are satisfactory both for the melting process and for saving energy.

4481024 Heat recovery system for glass tank furnaces

4481024 Heat recovery system for glass tank furnaces

Hot repairs to a glass-tank furnace roof

Hot repairs to a glass-tank furnace roof

Mathematical model of glass tank furnace with batch melting process

A mathematical model of glass tank furnace incorporating the batch melting process more realistically, has been developed. The batch model includes the effects of chemical reaction, phase change and heat flux from combustion flame and melt glass. Consequently the melting down position of batch is treated as a dependent variable in the model. By combining this new batch model with the already developed models which consists of the radiation model and melt model, the physical phenomena important to glass process can be grasped much more realistically. The model has been checked with operating data gathered from actual furnaces. Consequently validity of the model is assured. The model is widely utilized for cold repairs and new furnace designs.

Studies on refining and homogenizing progress by the two-dimensional numerical model

The extent of the refining and homogenizing progress was studied on the basis of residence time, thermal history and reduction of inhomogeneity. The results were compared with the performance of six actual furnaces respectively. Furthermore, the study was made on the effect of the imaginary alteration with respect to some factors of a glass tank furnace.

Service of refractories in a glass-tank furnace producing glass fiber by the single-stage method

Chromium oxide blocks developed by the Ukrainian Scientific-Research Institute of Refractories from fine-grained and coarse-grained compounds, like the chromium oxide refractories S-1215 material made by the Corhart company of the USA, ensure a high resistance in the linings of the tanks of glass furnaces producing glass fiber. Their wear occurs on account of chemical solution in the glass at temperatures above 1500°C.

Criteria for the Selection of Liquids for Physical Models of Glass Tanks

The similarity between models and prototypes of glass tank furnaces is analyzed, considering both the hydrodynamic and thermodynamic aspects of the problem. By applying inspectional analysis to the Navier‐Stokes equations and to the first principle of thermodynamics, suftkiently similar conditions are obtained between model and prototype. Such conditions are used to choose the best liquid to simulate the melted glass. It is concluded that the selection of a liquid for the model requires that the hydrodynamic and thermodynamic aspects of the problem be considered, that a set of conditions may be established to ensure the similarity between model and prototype, and that such conditions may generally be fulfilled by real liquids.

Rational organization of the degassing schedule in glass tank furnaces

Rational organization of the degassing schedule in glass tank furnaces

Increasing the output and improving the design of window glass tank furnaces

Increasing the output and improving the design of window glass tank furnaces