Glastechnische Berichte : Zeitschrift für Glaskunde
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Browsing Glastechnische Berichte : Zeitschrift für Glaskunde by Author "Barklage-Hilgefort, Hansjürgen"
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- ItemIndustrial experience with a cathodic electrochemical method to reduce the molybdenum electrode corrosion(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1993) Fleischmann, Bernhard; Mergler, Kurt Wilhelm; Barklage-Hilgefort, HansjürgenIn an industrial all-electric glass tank a cathodic dc voltage was superimposed on the ac heating voltage at two molybdenum electrodes for about 8 months to reduce the corrosion through the formation of a protective layer. One starting electrode could be used as counter electrode for the cathodic protection of the molybdenum heating electrodes. A platinum electrode was installed as reference electrode to carry out electrochemical measurements (impedance measurements, current-potential curves). After an 8 months' running time a reduction of molybdenum corrosion of about 25 % could be proved due to the cathodic protection in comparison with unprotected heating electrodes. The results of the electro chemical investigations on the industrial glass tank showed to a certain extent deviations from the former laboratory tests.
- ItemModeling of the aging of glass furnace regenerators(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1992) Beerkens, Ruud G. C.; Muysenberg, Hendrikus P. H.; Barklage-Hilgefort, HansjürgenΑ model has been developed to predict the decrease of the thermal performance of glass furnace regenerators due to fouling by flue gas condensates. The model consists of four parts: a) description of the thermal performance (heat transfer) of regenerator checkers; b) description of the heat transfer in the furnace combustion chamber; c) determination of volatilization of sulfur, chloride and sodium components from the melt; d) modeling of chemical reactions in and deposition from flue gases in the regenerator. The aging and the reduction of the thermal efficiency due to fouling has been predicted: - for different checkerwork constructions or refractory types; - as a function of pull rate; - as a function of glass melt temperatures; - as a function of applied cullet fraction. Depending on the different conditions, the predicted increase in energy consumption is about 1 up to more than 3 %/year, mainly due to fouling. Cruciform and chimney block checkers seem to be less sensitive for this fouhng than basketweave packings. As molten glass temperatures increase, dust emissions and fouling rates are going up. According to the model calculations, a higher cullet fraction in the batch will lead to reduced aging rates of the regenerators. The model is in quite good agreement with practical observations in industrial furnaces.
- ItemPractical experience with raw-material preheating on glass melting furnaces(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1992) Enninga, Gerhard; Dytrych, Karel; Barklage-Hilgefort, HansjürgenBy preheating the raw materials using the energy of the flue gases after leaving the air-preheating system energy savings of about 20 to 25 % are possible on glass melting furnaces. At the same time, the flue gases are cooled down to temperatures, which are necessary for the cleaning process that follows in the electrostatic precipitator. The preheating of the raw materials has been often discussed in the past, but that time at no suitable heat exchanger was available. Furthermore, there also were many other possibilities to improve the thermal performance of glass melting furnaces, for example better air preheaters, a better insulation of the installation of better burner systems. Nienburger Glas GmbH has been working in the field of batch preheating since about ten years. The preheater, which was developed, works with direct contact of flue gas and batch in a cross-counter flow; the flue-gas ducts are set up by angle irons with the corner at the top side. During the preheating process also most of the acidic components, for example sulphur oxides, chlorine and fluorine, are removed out of the flue gases. After beginning with a small experimental setup a batch preheater for a cross-fired green glas furnace with a pull rate of about 300 t glass/d was designed and built in cooperation with GEA Energietechnik GmbH, Bochum (FRG). This batch preheater has been operated since about 4 years with a cullet content of about 80 to 90 %. The next step in developing this new technique was the installation of a batch preheater on a cross-fired furnace with a capacity of about 350 t glass/d, which is used for the production of white glass with a cullet content of 30 to 50%. Moreover, the first batch preheater for an end-fired furnace has recently been taken into operation. This paper will report about practical experiences with the existing batch-preheating systems. The energy consumption will be treated as well as the emission of sulphur oxides, chlorine and fluorine, the preheating temperatures, the melting behaviour of the furnace, the carry over of dust to the regenerators and the quality of the produced glass.