DE202020107034U1 - Glass melting furnace with conversion area for converting glass batches - Google Patents

Abstract

Glass melting furnace with the conversion region (1) for converting the glass batch (5) into glass melt (13) comprises:
the conversion region (1) with the layer of the glass mixture (5) on the molten glass melt (13), which is the bottom (7), the opposite side walls (10 and the front side (14), is provided with two side entrances (2) and is heated with heating electrodes (3) and gas burners (4); and
the conversion region (1) is followed by the homogenization region (6), which is heated fully electrically for the homogenization of the glass melt (13) and is characterized in that
the conversion region (1):
a) has a side entrance (2) on each opposite side wall (10);
b) is equipped with vertical rod electrodes (3) placed in the floor (7) and vertical gas burners (4) placed in the vault (8);
c) has vertical rod heating electrodes (3) distributed over the entire surface of the floor (7) and gas burners (4) over the entire surface of the vaults (8) in regular formations;
d) the axes (9) of the vertical electrodes (3) have a minimum distance of 0.3 m from one another and from the walls (10, 14);
e) the axes (11) of the vertical burners (4) have a minimum distance of 0.5 m from one another and from the walls (10, 14); and
f) that the tips (12) of the electrodes (3) are a maximum of 0.4 m away from the lower surface of the layer of the glass batch (5).

Description

Technical area

The invention relates to a glass melting furnace with a conversion region for converting the glass batch into the glass melt. The conversion region with a high concentration of heating energy for converting the glass batch into the glass melt has a layer of glass batch on the molten glass melt. The conversion region, consisting of the floor, opposite side walls and a front wall, has two side entrances and is heated by electrodes and gas burners. The glass melting furnace further comprises the fully electrically heated homogenization region for the homogenization of the glass melt, which adjoins the conversion region.

The current state of the art

A continuous glass melting furnace with a horizontal flow of the melt can be distributed into the input (conversion) region with the mixture layer on the surface and the homogenization region in which the melting processes are ended, especially the dissolving of the quartz sand and the removal of bubbles [5] . Their measurable performance is usually between 2 to 3 t · m ^-2 · day- ¹ , in top systems, usually with electrical heating, up to 4 t · m ^-2 · day ^-1 [6]. The problem with these ovens is the low conversion speed of the batch as a result of the only little intensive heat transport into the batch [3] and the extensive homogenization region. Part of the energy is supplied from the homogenization region to the conversion region by the reverse circulation flow of the melt and as a result of this circulation flow, large areas unused for the implementation of the homogenization processes arise in the homogenization region. In order to achieve a sufficient homogenization capacity, it is therefore necessary that the homogenization region is spacious [5, 7].

The cited low conversion rate of the batch into glass in the conversion region is achieved by accelerating the kinetics of the conversion process, above all by improving the heat transport into the batch layer, e.g. B. solved by electrical heating [8] or by optimizing the conversion mechanism [9].

The cited problem of the large homogenization region and its low use for the homogenization processes can be solved in two different ways.

The first way uses the separation of the processes of the individual melting processes in associated separate areas, which z. B. in a segmented melting furnace - example is the melting furnace according to Beerkens [10] (segmented melter) - is realized. By dividing the furnace into several small rooms depending on the individual processes, the conditions for its operation are improved and backflows of the melt from the current to the previous room are prevented, so that unused areas for the actual melting process are not formed. In general, however, this creates a complicated system with difficult coordination of the processes in the individual sub-areas.

The second way is described in patent CZ 307 659 [19]. It is the melting area of a continuous melting furnace with a glass inflow with inhomogeneities and the way the glass melts in this area. The melting process in a room is separated into only two regions and the distribution of the heating energy influences the flow in the homogenization region of the melting room in such a way that its unusable areas are limited, possibly even completely eliminated, and the homogenization capacity of the room is fundamentally increased.

In the patent CZ 307 659 [19] and [1, 2] the relative size “use of the melting space” was introduced, which makes it possible to quantify the quality of the flow with regard to the course of the melting process. This size achieves the value 1 for piston flow, a value between 0.45 to 0.65 for a uniform flow [11] and a value of 0.6 to 0.8 when a spiral flow occurs [12, 13, 14]. The occurrence of a spiral flow in the glass melting chamber is indicated by Czech patents [15, 16] and the corresponding PCT application [17], which describes a glass melting furnace for continuous glass melting and for the melting process.

The ascertained use of the melting room for an industrially operated glass furnace with a mixture layer on the surface was, however, very low, between 0.05 and 0.1 [3]. These industrial furnaces are characterized by low utilization values. The reason for this was the previously mentioned recirculating flow between the homogenization and the conversion part of the furnace. It therefore appears as perspective to increase the use of space significantly by means of the flow control mentioned. By modeling the homogenization module with the entry of the glass melt containing grains of sand and bubbles and with the flow control in the further part of the module, it was possible to achieve a flow that is similar to the uniform flow and that has a utilization value of 0.5 and achieves a melting capacity of up to 600 t / day [4]. The dimensions of such a homogenizing module were significantly smaller than those of an industrial melting room and were around 12.5 m ³ . The conditions for operating this homogenization module describe the melting chamber of a continuous glass melting furnace [18, 19, 20, 21].

The mentioned second homogenization region was already identified by the authors by studying the character of the flow in the homogenization module with the entry of undissolved quartz sand and bubbles (without glass batch) with the help of the "use of the melting space" [1, 2] and the theoretical relationships , which enable the achievement of an optimal flow type [3, 4], solved. The setting of a controlled flow with the help of the mathematical model showed an increase in the homogenization performance up to a multiple. Such a controlled flow of the molten mass was achieved by a suitable spatial distribution of the heating energy. This resulted in a small homogenization module - a small homogenization room - with a specific melting capacity which, in the optimal case, far exceeded ^{30 t · m -3} · day ^-1.

In the subsequent inclusion of the batch conversion process in the melting process, it therefore seems logical to connect the homogenization module mentioned with a certain region for the conversion of the glass batch. In the assembled melting space, the proposed space with the mixture would then be the first, the conversion region and the homogenization module that has already been released would be the second, the homogenization region. The conversion region must of course have performance parameters comparable to those determined for the homogenization region.

The aim of the invention is a new conversion region of a continuous glass melting room which guarantees a high power consumption of energy and which, via its built-in heating, ensures the conversion of a considerable amount of glass batch in a relatively small room.

The essence of the invention

This object is achieved by the glass melting furnace according to the preamble of claim 1 of this invention, the essence of which is that the conversion region: is provided with a side access on each opposite side wall; is equipped with vertical stick electrodes placed in the floor and vertical gas burners placed in the vault; has vertical rod heating electrodes distributed over the entire floor area and vertical burners distributed in regular formations over the entire vaulted surface; has vertical electrodes, the axes of which are placed at a minimum distance of 0.3 m from each other and from the walls; has vertical burners placed at a minimum distance of 0.5 m from each other and from the walls; Has electrode tips that are a maximum of 0.4 m away from the lower limit of the layer of the glass mixture.

The main advantage of this invention is that the conversion region has a large conversion capacity thanks to the high energy concentration in a relatively small space. The conversion region as the first part of the glass melting furnace uses the intensive melting of the glass batch on the surface of the melt through a targeted combined heating of the network of vertical burners and the network of appropriately distributed vertical electrodes, which cause vertical currents of the hot melt to form the batch layer. The power consumption in the region is chosen so that the amount of energy supplied guarantees the conversion of the entire measured batch into molten glass. With this arrangement, the specific speed of the conversion of the batch into glass was about three times higher than that achieved in a conventional glass furnace with regenerative (gas) heating and lower electrical heating. According to this invention, the size of the new conversion region approaches the homogenization region and the expected concrete total size of both regions of the furnace is between 24 and 30 m ³ . When the conversion region was completely covered by the glass batch, the melting rates were high and exceeded 300 t of glass per day. The capacity of the conversion region is increased in a controlled manner by an increase in the energy share for the conversion region (k ₁ ), furthermore by adapting the ratio between the amount of electrical and combustion energy and by letting the mixture into the homogenization region. The proposed mechanism of the conversion of the mixture in melt was found to be effective.

The vertical position of the electrodes and burners enables the majority of the heat to be conducted from below and above to the batch layer and creates vertical circulations in the glass melt along the electrodes, which accelerates the transfer of convection heat into the batch and removes the colder melt from its lower limit away.

A favorable placement of the regular formations of the vertical heating electrodes and the vertical heating gas burner causes these energy sources with the hot vertical flows of melt and exhaust gases all with the Achieve a mixed covered area and increase the conversion capacity of the conversion region.

Compliance with the asserted distance of the mutual distance of the vertical electrodes, as well as their asserted distance from the side walls and from the front wall of the conversion region are safe and limit the mutual influence of the effectiveness of the electrodes on the bottom and the walls of the conversion region.

Compliance with the requested distance of the mutual distance between the vertical gas burners and their requested distance from the side walls and the front wall of the conversion region are safe and limit the mutual influence of the effectiveness of the heating gas burners on the walls of the conversion region.

The purpose of the requested and relatively short distance between the electrode tips from the lower surface of the mixture is a quick and instantaneous removal of the currently heated glass melt, which rises fastest at the tips of the electrodes, to the lower surface of the mixture. Distances of 0.3 to 0.1 m proved to be favorable. It is unfavorable if the electrode tips touch the glass batch directly, where the temperature of the glass melt is significantly lower. Relatively long electrodes with a length that reaches directly to the surface of the glass batch ensure a high conversion capacity from.

It is advantageous if the conversion region has a proportion of the electrical energy of the heating electrodes in relation to the total energy supplied to the region with heating electrodes and burners of at least 50%, more advantageously from 60 to 80%. The highest conversion speeds of the glass mixture could be achieved in this area. Optimizing the proportion of electrical energy can lead to an increase in the conversion rate of 20 to 30% compared to an only estimated proportion.

It is also advantageous if the vertical heating electrodes are molybdenum rod electrodes. A significant number of electrodes are installed in the conversion region, and it is therefore advantageous to use rod electrodes that can withstand high energy concentrations, which the molybdenum rod electrodes meet. Unsuitable are e.g. B. Tin rod electrodes or molybdenum plate electrodes.

It is also advantageous if the vertical hot gas burners are heated with natural gas with air or oxygen. This is a common practice and a widely used combustion heater, while oxygen is a relatively newer but more expensive heater.

Or the vertical gas burners can be heated with hydrogen with air or oxygen. It is a newly considered heating system that does not leave any traces of carbon and is therefore ecologically favorable, albeit relatively more expensive.

The invention also relates to the way in which the glass batch is converted into the glass melt in the glass melting furnace according to this invention, the main point being that the electrodes and the gas burners in the conversion region 6,000 to 14,000 kW for the conversion of the glass batch into glass melt for the creation 3 to 7 kg of glass can be fed in per second.

It is also advantageous if the conversion rate of the conversion of the glass batch into the glass melt is between 0.25 and 0.30 kg × m ^-2 × s ^-1 .

Under these controlled and set conditions, the energy is supplied to the conversion region via its own sources, i.e. via electrodes and gas burners that are effectively and optimally used for the conversion of the glass batch. In the subsequent homogenization region, the conditions for a uniform and spiral flow with a high space utilization can thus be better ensured.

1. 1. Durch die Verwendung einer optimal dichten Anordnung vertikaler langer Elektroden vom Boden aus konzentriert sich die hohe Leistungsaufnahme von Joule-Energie in einem kleinen Raum und richtet das Maximum der Leistungsaufnahme unter die Gemengeschicht Eine ähnliche Elektrodenanordnung kann auch für den Entwurf eines gesamtelektrischen Schmelzofens erwogen werden.
2. 2. Durch die Beheizung entsteht eine vertikale Zirkulation der Schmelze, die entlang der Elektroden nach oben zielt und nach Erreichen der Phasenschnittstelle sich umkehrt in Richtung nach unten. Die absteigende Strömung steht in Verbindung mit dem Abfallen der durch die Konversion des Gemenges entstandenen kalten Schmelze. Bei der Applikation der im Boden netzförmig angeordneten Elektroden bildet sich ein Strömungsbild in Form von vertikal zirkulierenden Zellen. Die heiße aufsteigende Schmelze attackiert senkrecht die Gemengeschicht und beschleunigt die Wärmeübertragung in das Gemenge, die entstandene kalte Schmelze wird durch die absteigende Zellenströmung schnell von der Phasenschnittstelle entfernt.
3. 3. An der Bildung der vertikalen Zirkulation in der Schmelze beteiligen sich ebenfalls die vertikalen Brenner. Die durch die kalte Schmelze entstandene absteigende Strömung bildet sich an der Kontaktstelle der heißen Abgase mit dem Gemenge.
4. 4. Die Nutzung der auf das Gemenge ausgerichteten vertikalen Brenner wird durch die Installation der erforderlichen Anzahl von Quellen ermöglicht und ermöglicht den direkten Kontakt der heißen Abgase mit dem Gemenge, was gleichzeitig die Bedingungen für eine hohe Wärmeabsorption und eine hohe Konversionsleistung der Region begünstigt
5. 5. Zur Erreichung der Maximalleistung dient ebenfalls die Einstellung eines optimalen Verhältnisses zwischen der zugeführten elektrischen Energie (Elektroden) und der Verbrennungsenergie (Brenner), welches für verschiedene Typen der Konversionsregion zu konkreten Bedingungen einstellbar ist
6. 6. Durch die Konzentration eines großen Anteils der Gesamtenergie in eine kleine Konversionsregion unter Verwendung der Funktion der vom Boden aus verlaufenden vertikalen Elektroden, die bis in die Nähe der Oberfläche des Gemenges reichen, und unter Verwendung der vertikalen Brenner in der Nähe beider Oberflächen des Gemenges wird ein großer Wärmegradient und eine große Fläche für die Wärmeübertragung durch radiales Verfließen der Schmelze und der Verbrennungsprodukte an der Oberfläche erreicht. Durch die örtlich sich ändernde Strömung werden auch die vorausgesetzten hohen Werte des effektiven Koeffizienten der Wärmeübertragung gewährleistet Dadurch sind optimale Bedingungen für eine schnelle Konversion des Gemenges in Glasschmelze gesichert
7. 7. Die in den Zellen absteigenden Schmelzströme sind ausreichend schnell, wodurch diese in der Lage sind, entstandene kleine und größere Blasen in die Tiefe der Schmelze mitzureißen und die Blasen- und Schaumschicht, welche den Wärmeübergang von der Glasschmelze in das Glasgemenge verringert, zu stören.
8. 8. Das Verhältnis zwischen beiden Energietypen in der Konversionsregion, zusammen mit einer gegebenenfalls entstehenden Stelle freier Oberfläche der Schmelze an der Front der Konversionsregion unterstützen die Bildung von Bedingungen für den erwünschten spiralförmigen Strömungstyp in der zweiten Homogenisierungsregion des Ofens.

The advantages of the designed conversion region with the installed large electrical power consumption by means of vertical electrodes from the ground and vertical burners from the vault can be summarized as follows:

1. 1. By using an optimally dense arrangement of vertical long electrodes from the ground, the high power consumption of Joule energy is concentrated in a small space and directs the maximum of the power consumption under the mixture layer. A similar electrode arrangement can also be considered for the design of an all-electric furnace .
2. 2. The heating creates a vertical circulation of the melt, which aims upwards along the electrodes and, after reaching the phase interface, reverses downwards. The descending flow is related to the falling of the cold melt resulting from the conversion of the mixture. When the electrodes, which are arranged in a net-like manner in the ground, are applied, a flow pattern is formed in the form of vertical circulating cells. The hot, rising melt attacks the mixture layer vertically and accelerates the transfer of heat into the mixture; the resulting cold melt is quickly removed from the phase interface by the descending cell flow.
3. 3. The vertical burners also participate in the formation of the vertical circulation in the melt. The descending flow created by the cold melt forms at the point of contact between the hot exhaust gases and the mixture.
4. 4. The use of the vertical burners aimed at the batch is made possible by the installation of the required number of sources and enables the hot exhaust gases to come into direct contact with the batch, which at the same time favors the conditions for high heat absorption and high conversion efficiency in the region
5. 5. The setting of an optimal ratio between the supplied electrical energy (electrodes) and the combustion energy (burner), which can be set for different types of the conversion region under specific conditions, is also used to achieve the maximum output
6. 6. By concentrating a large portion of the total energy into a small conversion region using the function of the bottom vertical electrodes reaching near the surface of the batch and using the vertical burners near both surfaces of the batch a large thermal gradient and a large area for heat transfer is achieved through radial flow of the melt and the combustion products on the surface. The locally changing flow also ensures the required high values of the effective coefficient of heat transfer. This ensures optimal conditions for rapid conversion of the batch into molten glass
7. 7. The melt streams descending in the cells are sufficiently fast that they are able to carry along small and large bubbles into the depth of the melt and to disturb the bubble and foam layer, which reduces the heat transfer from the glass melt into the glass batch .
8. 8. The ratio between the two types of energy in the conversion region, together with any free surface area of the melt at the front of the conversion region, support the formation of conditions for the desired spiral flow type in the second homogenization region of the furnace.

Figure list

• : Axonometrische Ansicht der Konversionsregion eines Glasschmelzofens mit der Platzierung der Elektroden und Brenner und der angedeuteten Homogenisierungsregion.
• : Ansicht von , die die Projektionen der Platzierung der Brenner in der Gewölbe XY in der Konversionsregion mit der angedeuteten Homogenisierungsregion darstellt
• : Ansicht von , die die Projektionen der Platzierung der Elektroden in der Ebene XY in der Konversionsregion mit der angedeuteten Homogenisierungsregion darstellt
• : Ansicht von im Querschnitt in der Ebene YZ in der gegebenen Entfernung von der Frontwand der Konversionsregion, die die Wärme- und Strömungsfelder der Schmelze im unteren Teil der Konversionsregion und das Temperaturfeld der Abgase in ihrem oberen Teil zeigt Links unten wird die Ansicht von oben auf den Glasofen veranschaulicht, daneben wird die Temperaturskala von oben der gezeigten Konversionsregion dargestellt
• : Abhängigkeit der spezifischen Konversionsgeschwindigkeit M_sbatch (des Glasgemenges in die Schmelze) vom Energieanteil k₁ von der dem Ofen zugeführten Gesamtenergie.
• : STAND DER TECHNIK - zentraler Längsschnitt XZ eines klassischen regenerativen Glasofens [3], der die Längszirkulation der Schmelze zeigt mit dem Detail D, welches den Bereich des Ofens an der Grenze des geschmolzenen Glasgemenges betrifft, wie auch mit der entsprechenden Strömung und den detaillierten Temperaturen.
• : Aufsicht von auf das Gemenge auf der Oberfläche der Schmelze in der Konversionsregion und der angedeuteten Homogenisierungsregion. Im unteren Teil links wird die Ansicht der Ebene XY des Glasofens dargestellt und daneben wird die Temperaturskala der oben abgebildeten Konversionsregion gezeigt
• : Aufsicht von auf die höchsten Stellen der vertikalen Strömungszellen unter der Schichtscheide von Gemenge und Schmelze in der Konversionsregion im Schnitt XY, welcher in der gegebenen Entfernung von der oberen Oberfläche des Gemenges liegt und mit der angedeuteten Homogenisierungsregion. Im unteren Teil der Abbildung links wird die Ansicht in der Ebene XY des Glasofens verdeutlicht und daneben wird die Temperaturskala der oben gezeigten Konversionsregion dargestellt.
• : Axonometrische Ansicht auf eine andere alternative Konversionsregion im Raum eines Glasschmelzofens mit der Platzierung der Elektroden und Brenner und mit der angedeuteten Homogenisierungsregion.
• :. Aufsicht von , die die Projektion der Platzierung der Elektroden in der Ebene XY darstellt, wie auch die angedeutete Homogenisierungsregion.
• : Aufsicht von auf das Gemenge auf der Oberfläche der Schmelze in der Konversionsregion und die angedeutete Homogenisierungsregion.
• zeigt die Aufsicht von auf die höchsten Stellen der vertikalen Strömungszellen unter der Schichtscheide von Gemenge und Schmelze in der Konversionsregion im Schnitt XY, welche in der gegebenen Entfernung von der oberen Oberfläche des Gemenges liegen und die angedeutete Homogenisierungsregion. Im unteren Teil der Abbildung links wird die Ansicht in der Ebene XY des Glasofens verdeutlicht und daneben wird die Temperaturskala der oben gezeigten Konversionsregion dargestellt
• : Ansicht von im Querschnitt YZ in einer bestimmten Entfernung von der äußeren Frontwand der Konversionsregion, die die Ansicht auf die Wärme- und Strömungsfelder der Schmelze im unteren Teil der Konversionsregion und das Temperaturfeld der Abgase in ihrem oberen Teil zeigt. Im unteren Teil der Abbildung links wird die Ansicht in der Ebene YZ des Glasofens dargestellt und daneben wird die Temperaturskala der oben dargestellten Konversionsregion gezeigt
• : Axonometrische Ansicht einer weiteren alternativen Lösung der Konversionsregion eines Glasschmelzofens mit der Platzierung der Elektroden und Brenner und mit der angedeuteten Homogenisierungsregion.
• : Aufsicht von , die die Projektion der Platzierung der Brenner in der Gewölbe in der Ebene XY in der Konversionsregion, wie auch die angedeutete Homogenisierungsregion darstellt
• : Aufsicht von , die die Projektion der Platzierung der Elektroden im Boden in der Ebene XY in der Konversionsregion, wie auch die angedeutete Homogenisierungsregion darstellt
• : Aufsicht von auf das Gemenge auf der Oberfläche der Schmelze in der Konversionsregion mit der angedeuteten Homogenisierungsregion. Im unteren Teil der Abbildung wird die Ansicht des Glasofens in der Ebene XY dargestellt und daneben ist die Temperaturskala der oben gezeigten Konversionsregion.
• : Aufsicht von auf die höchsten Stellen der vertikalen Strömungszellen unter der Schichtscheide des Gemenges und der Schmelze in der Konversionsregion im Schnitt XY in einer bestimmten Entfernung von der oberen Oberfläche des Gemenges mit angedeuteter Homogenisierungsregion. Im unteren Teil der Abbildung links wird die Ansicht des Glasofens in der Ebene XY dargestellt und daneben ist die Temperaturskala der oben gezeigten Konversionsregion.
• : Ansicht von im Querschnitt YZ in einer bestimmten Entfernung von der äußeren Frontwand der Konversionsregion. Die Ansicht zeigt die Wärme- und Strömungsfelder der Schmelze im unteren Teil der Konversionsregion und das Temperaturfeld der Abgase in ihrem oberen Teil zeigt. Im unteren Teil der Abbildung links wird die Ansicht in der Ebene XY des Glasofens dargestellt und daneben wird die Temperaturskala der oben dargestellten Konversionsregion gezeigt

The invention is described in detail below using exemplary, non-limiting embodiments and explained with reference to the accompanying schematic drawings, which show the following:

• : Axonometric view of the conversion region of a glass melting furnace with the placement of the electrodes and burners and the indicated homogenization region.
• : View from , which represents the projections of the placement of the burners in the vault XY in the conversion region with the indicated homogenization region
• : View from , which represents the projections of the placement of the electrodes in the plane XY in the conversion region with the indicated homogenization region
• : View from in cross-section in the plane YZ at the given distance from the front wall of the conversion region, which shows the heat and flow fields of the melt in the lower part of the conversion region and the temperature field of the exhaust gases in its upper part, at the bottom left, the view from above onto the glass furnace is illustrated , next to it the temperature scale is shown from the top of the conversion region shown
• : Dependence of the specific conversion rate M _sbatch (of the glass batch into the melt) on the energy component k ₁ of the total energy supplied to the furnace.
• : PRIOR ART - central longitudinal section XZ of a classical regenerative glass furnace [3] showing the longitudinal circulation of the melt with the detail D, which concerns the area of the furnace at the boundary of the molten glass batch, as well as the corresponding flow and the detailed temperatures .
• : Supervision of on the mixture on the surface of the melt in the conversion region and the indicated homogenization region. In the lower part on the left the view of the plane XY of the glass furnace is shown and next to it the temperature scale of the conversion region shown above is shown
• : Supervision of to the highest points of the vertical flow cells under the layer of mixture and melt in the conversion region in section XY, which lies at the given distance from the upper surface of the mixture and with the indicated homogenization region. In the lower part of the figure on the left, the view in plane XY of the glass furnace is illustrated and the temperature scale of the conversion region shown above is shown next to it.
• : Axonometric view of another alternative conversion region in the space of a glass melting furnace with the placement of the electrodes and burners and with the indicated homogenization region.
• :. Supervision of , which represents the projection of the placement of the electrodes in the plane XY, as well as the indicated homogenization region.
• : Supervision of on the mixture on the surface of the melt in the conversion region and the indicated homogenization region.
• shows the supervision of to the highest points of the vertical flow cells under the layer of mixture and melt in the conversion region in section XY, which are at the given distance from the upper surface of the mixture and the indicated homogenization region. In the lower part of the figure on the left, the view in plane XY of the glass furnace is illustrated and the temperature scale of the conversion region shown above is shown next to it
• : View from in cross section YZ at a certain distance from the outer front wall of the conversion region, which shows the view of the heat and flow fields of the melt in the lower part of the conversion region and the temperature field of the exhaust gases in its upper part. In the lower part of the figure on the left, the view in the YZ plane of the glass furnace is shown and the temperature scale of the conversion region shown above is shown next to it
• : Axonometric view of a further alternative solution of the conversion region of a glass melting furnace with the placement of the electrodes and burners and with the indicated homogenization region.
• : Supervision of , which shows the projection of the placement of the burners in the vault in the plane XY in the conversion region, as well as the indicated homogenization region
• : Supervision of , which shows the projection of the placement of the electrodes in the ground in the plane XY in the conversion region, as well as the indicated homogenization region
• : Supervision of on the mixture on the surface of the melt in the conversion region with the indicated homogenization region. The lower part of the figure shows the view of the glass furnace in plane XY and next to it is the temperature scale of the conversion region shown above.
• : Supervision of to the highest points of the vertical flow cells under the layer sheath of the mixture and the melt in the conversion region in section XY at a certain distance from the upper surface of the mixture with the homogenization region indicated. In the lower part of the figure on the left, the view of the glass furnace in plane XY is shown and next to it is the temperature scale of the conversion region shown above.
• : View from in cross section YZ at a certain distance from the outer front wall of the conversion region. The view shows the heat and flow fields of the melt in the lower part of the conversion region and shows the temperature field of the exhaust gases in its upper part. In the lower part of the figure on the left, the view in plane XY of the glass furnace is shown and next to it the temperature scale of the conversion region shown above is shown

Examples of carrying out the invention

STATE OF THE ART

For comparison with the solution according to this new invention, the state of the art [3] is cited here, using an example solution of a classic regenerative glass melting furnace with a smaller electrical heater.

The enclosed represents the central longitudinal section XZ of a classic regenerative glass furnace with electrical heating, which shows the longitudinal circulation of the melt and the temperature under the batch layer, as well as a detail of the flow in the boundary area of the batch [3]. As already mentioned, part of the heat from the burners is transferred from the homogenization region to the conversion region with the longitudinal circulation. When modeling this regenerative industrial furnace with electrical heating and an average melting temperature of 1,387 ° C [3], however, it was found that when the batch is heated, the horizontal backflow of the hot glass, which comes under the batch from the homogenization region of the furnace and parallel with the Mix history in the conversion region continues, the values of the specific conversion speed are significantly lower than those that are achieved in the conversion region. The concentration of energy under the mixture is lower than it is in the case of the designed region, since the energy is supplied to a large area from the point with the maximum temperature. The energy is transferred into the mixture mainly at the front of the mixture. Furthermore, the temperature of the hot flow drops as a result of the fact that the resulting cold glass remains near the phase boundary for a long time In the longitudinal section the flow of the hot glass below the batch history, the detail of the area at the batch boundary is shown under the overall view on a central longitudinal section of the room arrows indicate the melt backflow below the batch, where the temperature brought about by the melt is above 1,500 ° C in front of the batch front. However, when it comes into contact with the mixture, it sinks quickly and at a greater distance from the front it moves in a range of around 1,350 ° C. The hot glass flowing towards the batch front with the maximum temperature realizes the most intensive melting at the batch front and a larger amount of cold melt is created here. Behind the batch front, the hot and fast-flowing glass moves relatively quickly under the resulting cold melt and also cools down without coming into close contact with the batch. This flow of the melt at the boundary to the batch can be clearly seen in the section detail. However, the intensity of the melting in the area behind the batch front is low. The combination of a slightly lower melting temperature, the type of heating and the character of the flow of the hot melt from the temperature maximum along the lower limit of the batch led in all tested cases to a low specific conversion rate of the batch, which was on average only 0.09 kg / (m ² s] moved. In such cases, an additional electrical heating system with heating from below can improve this situation very slightly. By modeling the above-mentioned regenerative melting furnace, it was found in 14 cases that if there was an additional electrical heating system under the batch There is heating, which supplies about 25% of the total energy, the specific conversion rate increases from 0.087 kg / (m ² s] to about 0.093 kg / (m ² s] [3]. However, this is still a low value in comparison with the values from 0.27 kg / (m ² s] to 0.30 kg / (m ² s], which in the arrangement proposed here can be achieved.

example 1

(Figures 1-5, 7, 8)

A possible specific design of a glass melting furnace is shown schematically in shown. The glass melting furnace includes the conversion region 1 with the indicated homogenization region 6th . The conversion region 1 consists of the ground 7th , the opposite side walls 10 and the front wall 14th . It has two side entrances 2 for introducing the glass mixture 5 , always an entrance 2 on each of the opposing side walls 10 . The conversion region 1 is heated in combination, and that with electrodes 3 and gas burners 4th . Both sources have a high concentration of heating energy for converting the glass mixture 5 into the glass melt 13th . The glass melting furnace also includes fully electrical heating of the homogenization region 6th that refer to the conversion region 1 adjoins the conversion region 1 is covered with vertical stick electrodes that are in the ground 7th and with vertical gas burners 4th that are in the vault 8th the conversion region 1 are located. In the conversion region 1 are the vertical rod heating electrodes 3 over the entire surface of the floor 7th and the vertical burners 4th over the entire area of the vault 8th distributed in regular formations. The axes 9 of the vertical electrodes 3 are at a minimum distance of 0.3 m from each other and with the same minimum distance from the side walls 10 or the front wall 14th of the conversion room 1 arranged. The axes 11 the vertical burner 4th are at a minimum distance of 0.5 m from each other and with the same minimum distance from the side walls 10 or the front wall 14th of the conversion room 1 arranged. The tips 12th of the electrodes 3 are from the lower surface of the jar 5 a maximum of 0.4 m away. The vertical heating electrodes 3 are stick electrodes made of molybdenum with a length that directly attaches to the surface of the glass mixture 5 enough. The vertical hot gas burners 4th can be heated with natural gas with air or oxygen; or with hydrogen mixed with air or oxygen.

Thus the high homogenizing performance of the homogenizing region 6th can be used practically with the controlled flow, this must be an intensive conversion of the glass mixture 5 precede in glass as the events of the conversion of the mixture 5 and homogenization (dissolving the quartz sand and eliminating the bubbles in the region with the controlled flow) are in series. This creates a space with two regions 1 , 6th , the conversion region 1 and the homogenization region 6th . It is desirable to have the conversion region in a complete melting chamber structured in this way 1 sufficient capacity for the heating and conversion of the mixture 5 has, and that with a volume of the conversion region 1 , which is roughly comparable to the volume of the homogenization region 6th . Thus the resulting facility would be with the two connected regions 1 , 6th also relatively small. The proposed first conversion region 1 of the glass melting furnace, that of the homogenization region 6th is preceded by the controlled flow, this invention fulfills this requirement.

The concrete solution for the conversion region 1 according to this invention, anticipates a power consumption of energy in the conversion region 1 that is sufficient for the conversion of the mixture 5 in glass in an amount corresponding to up to hundreds of tons of glass per day using a comparable amount of energy to that of the electrodes 3 and the heat of combustion from the burners 4th with controlled placement of the electrodes 3 in the melt 13th and the burner 4th in the conversion region 1 with an inherent volume, which takes into account the volume of the homogenization region 6th a maximum of a few dozen m ^{3 is} reached (for comparison: the melt volume of a classic furnace with a medium to higher melting ^{capacity is around 100 m 3} , the melt area from 80 to 100 m ² depending on the depth of the melt 13th ). The conversion performance of the new conversion region 1 according to this invention approaches the homogenization performance of the second homogenization region 6th . The new conversion region 1 of the glass melting furnace, which is responsible for the conversion of the batch 5 is not determined by the further homogenization region 6th firmly separated, however, is functionally independent. The surface of the melt 13th in the conversion region 1 of the glass melting furnace is partially or completely covered by the layer of the mixture 5 covered. The size of the conversion region 1 and the degree of surface coverage of the melt 13th depends on the expected performance. Usually, the conversion region is completely filled 1 with the mix 5 expected. In the interest of a high melting capacity, it is possible in some cases that the mixture 5 partially up to the second homogenization region 6th The homogenization region extends into it 6th As the second part of the melting chamber, it has a controlled flow of the melt 13th and this region 6th is attached to the designed conversion region for the dissolution of the glass mixture 5 added.

More detailed.

According to has the designed conversion region 1 two side entrances 2 for the glass batch 5 at the level of the surface of the molten glass 13th . The entrances 2 are mostly for the middle of the sidewalls 10 provided and their width takes about half of the side walls 10 the conversion region 1 one, in the given specific example 1 m. The localization of the entrances 2 in the side walls 10 towards each other is not binding, but is beneficial for the conversion of the mixture 5 in glass when filling the conversion region 1 with the mix 5 . Both streams of the mixture meet near the longitudinal axis of the conversion region 1 each other, slow down, and thereby at the given point the disintegration of the mixture 5 accelerated. With regard to the dimensions, the capacity and the conditions in the subsequent homogenization region 6th of the furnace's melting chamber, as well as the first model experience with the conversion of the mixture 5 has the basic variant of the designed conversion region 1 of the glass melting furnace, for example, a width of 6 m and a length of the side walls 10 of 2 m. So the surface of the melt has the designed conversion region 1 a size of 12 m ² ; with a layer thickness of the melt 13th 1 m gives a volume of 12 m ³ . The proposed size thus corresponds to that of the homogenization region 6th , which has a volume of 12.44 m ³ When dimensioning the capacity and the placement of the heating elements of the conversion region 1 depends on the capacity of the homogenization region 6th of the furnace assumed the rate of 6 to 7 kg / s (around 500 to 600 t / day) with an average process heat of 1,420 ° C [4] and a maximum permissible load after complete decomposition of the incoming quartz sand and after elimination of the incoming bubbles of the heat sources. The corresponding amount of the mixture for the conversion 5 and the partial melting of the corresponding amount of glass is the conversion region 1 with combined heating by means of burners 4th and electrodes 3 equipped, with the proportion of over the electrodes 3 Joule heat delivered to the in the conversion region 1 total energy supplied half to the majority. The vertical electrodes 3 from the soil 7th whose tips are close to the layer of the mixture 5 are single-phase or three-phase connected in regular formations, and the arrangement is designed so that their direct heating influence the entire lower surface of the layer of the mixture 5 includes. The effort to arrange the electrodes 3 also aims at inducing vertical hot currents that are perpendicular to the lower side of the mix 5 straighten and thereby the transfer of heat into the mixture 5 accelerate the convection. The one in the vault 8th the conversion region 1 housed burner 4th are also perpendicular to the top surface of the mix 5 directed and are distributed so that the exhaust gases cover the entire top surface of the mixture 5 wash around. In the given conversion region 1 there is a high concentration of heating energy generated by the electrodes 3 and the burner 4th on the layer of the mixture 1 is aligned. The mix 5 usually covers part or all of the area of the designed conversion region 1 . The exhaust gases pull over the surface into the second homogenization region 6th of the furnace and can partially reduce the heat loss of the vaults 8th replace.

shows the axonometric view of the conversion region 1 a glass melting furnace for the decomposition of the glass mixture 5 with the typical arrangement of the heating electrodes 3 and the burner 4th .

For the basic variant there are 8 vertical burners 4th in the vault 8th suggested their arrangement in is cited. The location of the eight burners 4th in the vault 8th is indicated by circles. The burners 4th are directly on the upper surface of the layer of the mixture 5 aligned. In each half of the conversion region 1 there are three burners 4th in triangular format near the entrance for the batch 5 , two burners 4th are one behind the other in the axis of the inputs 2 closer to the center of the conversion region 1 appropriate. This will ensure a good coverage of the mix 5 achieved with hot exhaust gases. The exhaust gases reach the second homogenization region 6th and escape through the outlet (outlet) above the outlet of the melt 13th .

then shows the projection of the arrangement of the electrodes 3 in plane XY of the conversion region 1 . The electrodes 3 are indicated here by small circles in squares. According to the picture, they are in the conversion region 1 36 vertical electrodes in total 3 placed in alternating or in-line formations connected in single-phase and three-phase.

Joule heat is considered to be the basic type of heating because it should have a greater capacity than gas heating. Thus, if necessary, a maximum homogenization capacity of the second homogenization region 6th of about 7 kg / s (approx. 600 t / day) [4] can be achieved, it is necessary in the first conversion region 1 to arrange a sufficient number of sources of electrical energy. For the melting of 1 kg glass / s from a mixture with 50% broken glass and heating from room temperature to an average temperature of 1,420 ° C, approx. 2,050 kW are required. The maximum total heating capacity in the first conversion region 1 should therefore be 15,000 kW. This is what happens in the first conversion region 1 to a high concentration of energy that is close to the layer of the concoction 5 should be focused. With the joint operation of both regions 1 and 6th of the glass furnace, it is assumed that the maximum melting (conversion) output achieved is somewhat lower than the maximum output of the actual homogenization region 6th is. This is the maximum amount of molten glass in the batch 5 was estimated at 400 to 500 t / day (approx. 5-6 kg / s) when optimal conditions were achieved in the entire furnace. The reason for a reduction in the imaginary melting capacity is the prerequisite, which emerges from the preliminary calculations, that the conversion region proposed afterwards 1 with a high flow rate of the batch 5 not all of the energy supplied because of the slower absorption kinetics of the heat and the disintegration of the mixture 5 must absorb. The necessary maximum total amount of energy would then move with the losses around 12,500 kW, with the heat that the burners 4th is roughly calculated with 2,500 kW, the assumed proportion of electrical energy in the conversion region 1 total energy supplied is 80%. For the delivery of Joule heat it is necessary in the conversion region 1 with a volume of 12 m ³ (6 m × 2 m × 1 m) to place electrical sources with a power of 10,000 kW. Such a high amount of energy requires a technically solvable and one on the part of the process of heating and conversion of the mixture 5 suitable arrangement of sources.

The heating took a long time, from the floor 7th the conversion region 1 outgoing vertical electrodes 3 chosen so that a required number can be arranged in a relatively narrow space. The electrodes 3 have a diameter of 76 mm, but thicker electrodes can also be used 3 (e.g. 100 mm) can be selected; the length of the electrodes 3 in the conversion region 1 is 0.8 to 0.9 m, the not inconsiderable length of the electrodes 3 allows the melt 13th to supply the maximum amount of energy and a large amount of energy directly under the mixture 5 to bring where the tips are 12th of the electrodes 3 are located. The entire space of the conversion region should be used for melting 1 and the usual minimum distances between the electrodes should be used 3 (approx. 300 mm) must be respected. The standard case is based on the arrangement of 4 groups of three vertical electrodes 3 with three-phase connection at the point of each input 2 (the number of groups of three can be increased to six). In the middle between the entrances 2 are two rows of electrodes along the longitudinal axis of the furnace 3 arranged, each row with a number of 6 (in the case of 4 groups of three of electrodes 3 with three-phase connection), or a row in the longitudinal axis of the furnace, also in the number of 6 electrodes 3 (in the case of expanding the number of groups of three electrodes 3 per entrance 2 from 4 to 6). These electrodes 3 are connected in single phase. Overall, the basic variant comprises the first conversion region 1 36 electrodes 3 .

The arrangement of the electrodes 3 in the first conversion region 1 in the section XY is through the already mentioned In the example given here, a total of 2,590 kW were supplied to the burners 4th and 6th .130 kW of Joule heat to the electrodes 3 supplied, the proportion of Joule heat in the total amount of supplied energy was therefore 70.3%. The three-phase connected electrodes 3 were a total of 4,360 kW and the central electrodes, connected in two rows, single-phase 3 a total of 1,770 kW supplied. The energy was evenly divided into the individual connection types. To the conversion region 1 the homogenization region then closes at the entrance 6th whose presumed but not yet confirmed placement is in indicated The achievements of the two regions 1 and 6th of the furnace must be coordinated in the final phase, the ratio of the energy consumption to each other in both regions 1 and 6th of the furnace is expressed as the proportion of that in the conversion region 1 total energy delivered by the furnace in terms of energy in both regions 1 and 6th total energy supplied, this proportion being expressed by the symbol k ₁ . The task of this example is to determine the conditions for a high conversion performance of the conversion region 1 which is comparable to the known homogenization of the second region 6th is.

There are also other positions of the electrodes that are not listed here 3 possible, but the proposed relatively uniform arrangement of the electrodes turned out to be 3 under the surface of the glass mixture 5 as an advantage in terms of the conversion of the mixture 5 into the glass melt 13th , as well as the subsequent homogenization of the melt 13th in the homogenization region 6th of the part of the furnace. Overall, exists in the conversion region 1 a high specific concentration of energy, the long vertical electrodes 3 heat the melt 13th especially those located near the lower surface of the concoction 5 located tips 12th so that the highly concentrated energy is mainly in the layer of the melt 13th below the surface of the mix 5 concentrated At the same time, the kinetic conditions are very favorable, as they are perpendicular to the mixture 5 those along the electrodes 3 observed fast-flowing melt a fundamentally higher temperature ( 1 .480 to 1,500 ° C) than the average temperature in the conversion room 1 (1,420 ° C).

In the glass melt 13th then the desired circular cells of the vertically ascending and descending flow do not appear. The rising hot melt 13th mixes on the surface of the mixture 5 after intensive contact with the layer of the mixture 5 with the cold melt created by this contact 13th . The cooled melt 13th gets off the surface of the mix quickly 5 carried away by the descending circulating flow cells. The burners are also connected to the flow 4th involved, since at the point of contact of the exhaust gases with the mixture by conversion of the mixture 5 again melt 13th arises which the mixture 5 flows through and also places of sinking melt 13th among the crowd 5 forms, which can be independent, or with the points of the heating by means of the electrodes 3 sinking melt 13th unite. The resulting structure of the vertically circulating (cell) flow is therefore the result of the heating effect of the electrodes 3 and the burner 4th as well as the sinking of the cold, through the decomposition of the mixture 5 resulting melt 13th . Unless the surface of the melt 13th the designed conversion region 1 complete with mixture 5 is covered, the heat comes into the mixture 5 from the electrodes 3 below the free surface with direct contact of the exhaust gases with the surface of the melt 13th . Due to the resulting vertical circulation of the melt 13th the vertical temperature gradient in the melt decreases 13th which in turn is beneficial for setting a controlled flow of the melt 13th in the second homogenization region 6th of the oven is. Under the given temperature and convective conditions, this, as well as in other cases with a designed surface of the melt 13th that with the mix 5 was completely or only partially covered, the specific conversion rate of the mixture 5 between 0.27 and 0.30 kg / (m ² s).

The typical character of the resulting cell flow in the given example is shown in the cross-section of the designed conversion region 1 . For the evaluation of the conversion function of the given arrangement of the vertical electrodes 3 an example was chosen that a melt flow 13th with a value of 3.826 kg / s with a proportional value k ₁ = 0.863, where k ₁ corresponds to the given conversion region 1 represents the proportion of energy supplied in relation to the total energy supplied. Under these conditions, the surface of the entire conversion region was 1 with the mix 5 covered. In The small funnels of the melt, which sinks at a lower temperature, are also just below the phase separation layer 13th to see that through the action of both the electrodes 3 as well as the burner 4th arise. Your place in the layer of the mix 5 is indicated by vertical arrows in the figure. These funnels are sometimes the result of the electrodes working together 3 with the burners 4th , at other times they only belong to one source of heat.

_{The values M Sbatch} [kg / (m ² s ¹ )] of the mixture achieved for the specific conversion rate 5 into the melt 13th for further cases in this conversion region 1 the will be in The numerical values shown in the legend to show the flow of the melt 13th in the conversion region 1 in kg / s. It can be seen that the values of the specific conversion speed increase approximately linearly with the value k ₁ , ie with the increasing energetic load on the conversion region 1 .

The conversion type of the mix 5 of melting in the designed conversion region 1 thus differs from the conversion of the mixture 5 in the classic horizontal furnace with heating predominantly by fuel gases and with a strong and extensive circulating longitudinal flow.

In the new conversion region 1 exists in the melt according to this invention 13th at the phase separation a large temperature gradient of the whole with the mixture 5 covered area concerns, this large area of conglomeration 5 for direct heat transfer from the electrodes 3 into the mix 5 serves This area is created at the lower limit 15th of the mix 5 by radial flow of the hot melt flowing in vertically 13th that from the tops 12th of the electrodes 3 flows in, a further part of the area is then used for the vertical removal of the cold melt that has formed 13th . The melting of the mixture 5 by hot melt 13th and the elimination of the cold melt 13th So takes place on the whole, with the mix 5 covered area. It can be assumed that under the conditions of a local, intensive variable convection, higher values of the effective coefficients of temperature transfer are also achieved. This then creates the conditions for a large gradient, a large contact area and high transition values for an intensive heat flow from the melt 13th into the mix 5 given. The direct contact of the fuel gases, which is then practically over the entire upper surface of the mixture 5 run, ensures good heat transfer from above. The effect of the given type of heating and the resulting type of vertical cell flow is also in melt chambers with a vertical flow of the melt 13th where with the mix 5 simultaneously on the entire surface of the conversion region 1 (as in an all-electric furnace) is applicable. The cell flow is created here only by the action of the electrodes 5 , the molten glass is only created from below and is fed into the subsequent homogenization region 6th derived.

The type of heating and flow, and the type of electrodes that are relatively close together 3 and the vertical burners 4th in the conversion region 1 increase the specific conversion speed of the mixture 5 up to three times. In the cases examined, the one for delivery was below the batch 5 and to burners 4th certain proportion of the total energy is high (k ₁ > 0.7) and there was thus sufficient energy to melt the mixture 5 by means of a strong circular flow of the melt 13th to disposal. How out As can be seen, the specific conversion rate increased as expected with the proportion of that for the area of the mixture 5 total energy provided. Maximum values of k ₁ = 0.09 to 0.95 were achieved. As a result, a high k ₁ value is also essential for an effective connection with the homogenization region 6th advantageous as this is used for the formation of an effective uniform or spiral-shaped flow in this homogenization region 6th necessary is.

One central row or two central rows of electrodes 3 in the area of the longitudinal axis of the designed conversion region 1 then helps with heat transfer to the confines of the mix 5 and supports the end of the conversion of the mixture 5 and the creation of a spiral flow of the melt 13th in the subsequent homogenization region 6th of the furnace is very effective (see the cross circulation in the middle part of the ).

From the above it can be seen that the flow character in the conversion region 1 of the furnace does not affect the flow in the subsequent homogenization region 6th is similar, with the conversion region 1 is designed more like a mixing region than a space with laminar parallel flow. As a result, the furnace is a system with two clearly different and controlled flow characters and through the connection of both regions 1 and 6th What must be achieved is that these different characters of the mixing region and the subsequent uniform or spiral flow are preserved.

Filling the conversion region 1 with the mix 5 and the course of the conversion of the mixture 5 are further discussed in the following and demonstrated.

with a view of that on the surface of the melt 13th floating mix 5 shows that the mix 5 partially in the second homogenization region 6th has advanced. A strip of higher temperature in the longitudinal axis of the conversion region 1 (darker shade) shows an increased conversion of the mixture 5 at the point where the two streams meet. The flow the melt 13th was 3.826 kg / s with a value k ₁ = 0.863.

then shows the view from above of the vertical flow cells under the phase divide of the mixture 5 and the melt 13th in the first conversion region 1 . These are the highest points of these vertical cells, which are approximately the shape of a rectangle. The darker parts of the high temperatures appear above the peaks 12th of the electrodes 3 and are associated with areas of descending flow of the melt 13th around the electrodes 3 that the mix 5 melt away, surround around. The lighter rings are areas of lower temperatures with the descending streams of the melt 13th . The flow values for the melt 13th and the value k ₁ are the same as in FIG .

The achieved performance of 3.83 kg / s (328 t / day) in the given example (as well as in the two other examples in with the same flow rate) is initially even lower than the maximum homogenization capacity of the second homogenization region 6th of the furnace. That is why it arises in the homogenization region 6th a melt reserve. In eliminating this reserve it will be necessary to increase the conversion capacity of the mixture 5 to increase what will happen when the in the first conversion region 1 The amount of energy supplied increases, and this happens by increasing the after in the first conversion region 1 delivered energy share, or - as further results showed - by a slight lowering of the in the homogenization region 6th delivered energy share. The final value of the conversion performance can only be achieved after harmonization of the course of the melting process (dissolution of the sand, elimination of the bubbles) in the homogenization region 6th of the furnace. The example demonstrated, however, shows that the selected shape, size and manner of heating the conversion region 1 an acceptably high capacity for effective conversion of the batch 5 in melt 13th to have.

Example 2

(Figures 9-13)

The subject of the example is an alternative conversion region 1 for the transformation of the glass mixture 5 , which has the same dimensions as in the previous example, but with the anticipated future adaptation of the conversion region 1 with mixed heating in a fully electric oven. That is why the electrical heating capacity was under the layer of the mixture 5 increased to approx. 12,000 kW in the conversion region proposed here 1 became the same arrangement of the burners 4th as in Example 1 maintained. The axonometric view of the lower part of the conversion region 1 with the electrodes 3 shows . The conversion region 1 again has two side entrances 2 for the mix 5 . At every entrance 2 there are 6 groups of three electrodes in a row by two 3 three-phase connected, so there is a total of in the region 12th Groups of three three-phase connected electrodes 3 . In the long axis of the conversion region 1 there is a row of 6 single-phase connected electrodes 3 so the total number of electrodes 3 in the conceived conversion region 1 is 42. The vertical electrodes 3 have a diameter of 100 mm, their length is 0.8 m, whereby the length can be increased to 0.9 m (tested). The conversion region 1 is again from above with eight vertical burners 4th in the same configuration as in example 1 ( ) heated In the given test case, 1,834 kW were supplied to the burners 4th and 6,254 kW to the electrodes 3 delivered, i.e. the proportion of Joule heat in the total energy delivered is 77.3%. To the three-phase connected electrodes 3 5.538 kW were delivered evenly to the central row of single-phase connected electrodes 3 a total of 716 kW.

The view from above with the detailed arrangement of the electrodes 3 and looking at that easily into the second homogenization region 6th reaching in mixture 5 are schematically in the and shown.

shows when viewed from above that in this case 16 groups of three three-phase connected electrodes in each half of the conversion region 3 are arranged and in the longitudinal axis of the conversion region 1 a series of six electrodes connected in single phase 3 is located.

shows in section XY the surface of the melt 13th floating mix 5 , with the mix 5 not yet completely the conversion region 1 fills in, but partly in the homogenization region 6th reaches in. Under these conditions, the melt flow rate was 13th 3.50 kg / s and the value k ₁ was also 0.87.

In the given case, there was also an intensive melting of the mixture 5 by the hot vertical streams of the melt 13th from the electrodes 5 . The shape of the highest point of the flow cells around the individual electrodes 3 around is less clear when viewed from above than in the previous example, see where the darker hue of the highest points of the cells is the ascending flow of the hot melt 13th and the lighter areas the descending flow with the melted glass melt 13th represent. The dark area around the longitudinal axis clarifies free surface with high temperature. The conversion performance of the conversion region 1 was then the aforementioned 3.50 kg / s (302.4 t / day) and the specific speed of melting of the mixture achieved 5 was 0.294 kg / (m ² s ¹ ]. The character of the cell flow was retained.

shows the temperature fields of the melt in a cross section (YZ) 13th around the electrodes 3 around and in the combustion chamber of the conversion region 1 near the layer of the mix 5 , as well as the character of the vertical circulation flow in the melt 13th . The character of this flow caused by the heating by the electrodes 1 , through the burner 4th and the sinking cold melt 13th from the melted mixture 5 is caused is similar to that of Example 1. The occurrence of in the mixture 5 resulting descending streams of the melt 13th is again marked with arrows.

In the given case, an average specific conversion performance of the mixture was determined 5 of 0.294 kg / (m ² s], which can be improved slightly by increasing the value k _1. The total conversion capacity of the conversion region 1 of 302.4 t / day must be used when harmonizing the conversion performance with the performance of the homogenization region 6th of the glass furnace can _{be improved by increasing the value k 1} (similar to es for example 1 shows), as well as by changing the ratio of electrical and combustion energy, the entire conversion region can, as an exception, also 1 for the conversion of the mixture 5 until a corresponding capacity of the homogenization region is reached 6th be enlarged.

Example 3

(Figures 14-19)

The subject of the example is another alternative conversion region 1 with the same shape as in the previous examples, the designed conversion region 1 was however extended in the interest of increasing the conversion capacity. The length of the conversion region 1 was thus extended from the original 2 m to 2.75 m, its width remains at 6 m and the room has two side entrances with a width of 1.5 m, which are centrally located in the side walls 10 are located. The proposed volume of the conversion region 1 for the conversion of the mixture is 16.5 m ³ . An axonometric view of the lower part of the conversion region 1 with the electrodes 3 shows who have favourited Projections of the Vertical Burners 4th in figure 8 in plane XY of the designed conversion region 1 will be in shown how too the projections of the electrodes 3 in the ground 7th represents the burner 4th are marked by double circles, the heating electrodes 3 by circles in squares.

In the conversion region 1 are located at every entrance 2 nine groups of three three-phase connected electrodes 3 (in three rows of three groups of three each), in the longitudinal axis of the conversion region 1 is a series of eight electrodes connected in single phase 3 are arranged in total in the conversion region 1 62 electrodes 3 installed The diameter of the electrodes 3 is 100 mm. Above the surface are in the vault 8th ten vertical burners attached. Again, there are five double burners 4th , spread across the width of the conversion region 1 .

In the specific example, the constant power consumption is energy into the burner 4th 3,230 kW, with the energy on the burner 4th was evenly divided; the power consumption of Joule heat in the electrodes 3 In the demonstrated example it was 6,900 kW, of which 5,645 kW in the three-phase connected electrodes 3 and 1,255 kW into the single-phase connected electrodes 3 . The proportion of electrical energy in the conversion region 1 so was 68.1%. The energy was supplied to the individually connected electrodes 3 fed evenly. The resulting conversion rate was 4.4 kg / s with a value k ₁ = 0.85.

The covering of the surface with the floating mixture 5 shows a plan view from above for the given example . The strip of higher temperature in the long axis of the conversion region 1 (darker areas) indicate a higher conversion of the mixture 5 . The mix 5 fills this conversion region 1 completely off again.

In the conversion region 1 convection cells have formed again, their highest points below the layer of the mixture 5 in a top view demonstrated. The cells are localized by the rapid horizontal flow of the melt 13th deformed. In becomes the temperature field of the melt 13th around the electrodes 3 around near the layer of the mix 5 , as well as the character of the vertical circular flow created by the heating with the electrodes 3 and the burners 4th , as well as by the sinking of the melt 13th after the mixture has melted 5 The stronger coloring in the middle of the highest points of the cells indicates the ascending flow of the melt 13th , same as in the previous examples.

The temperature fields of the melt 13th around the electrodes 3 around near the layer of the mix 5 and the character of the vertical circular flow created by the heating with the electrodes 3 and the burners 4th , as well as by the sinking of the melt 13th after the mixture has melted 5 (indicated by arrows) in the conversion region 1 are then created in in a cross section of the conversion region 1 (YZ section) shows the flow of the melt 13th is 4.40 kg / s, the value k ₁ = 0.8. Under the given conditions with the mentioned flow of the melt 13th The specific conversion rate of the mixture was 4.4 kg / s (380 t / day) 5 0.264 kg / s. By increasing the value Ṁ _Sbatch , there is an increase in k ₁ in the harmonization of the performance of the designed conversion region 1 with the powerful second homogenization region 6th of the furnace.

List of reference symbols

1

Conversion region

2

Side entrances 2 to the conversion region 1

3

Electrodes

4th

Gas burner

5

Glass batch

6th

Homogenization region

7th

ground 7th the conversion region 1

8th

Vault 8th the conversion region 1

9

axes 9 of the electrodes 3

10

side walls 10 the conversion region

11

axes 11 the burner 4th

12th

sharpen 12th of the electrodes 3

13th

Molten glass

14th

Front wall of the conversion region 1

15th

border 15th of the glass mix 5

1. 1. L. Nèmec, P. Cincibusova, Ceramics-Silikaty 53 (2009) 145-155 .
2. 2. L. Nemec, P. Cincibusova, Ceramics-Silikaty 52 (2008) 240-249 .
3. 3. M. Jebava, L. Nemec, Ceramics-Silikaty 62 (2018) 86-96. https://doi.org/10.13168/cs.2017.0049
4. 4. L. Hrbek, M. Jebava, L. Nemec, J. Non-Cryst. Solids 482 (2018) 30-39. https://doi.Org/10.1016/i.inoncrysol.2017.12.009
5. 5. W. Trier: Glasschmelzöfen. Springer-Verlag, Berlin, Heidelberg, New York, Tokyo 1984 .
6. 6. A. Smrcek a kol.: Taveni skla, Ceska sklafska spolecnost o.s. Jablonec nad Nisou 2008, str. 280 .
7. 7. Z. Zhiquiang, Y. Zhihao. Basic flow pattern and its variation in different types in glass tank furnaces, Glast. Ber. Glass Sci. Technol. 70 (1997), (6) 165-172 .
8. 8. J. Stanek: Elektricke taveni skla, SNTL Praha 1986 .
9. 9. A. Paul: Chemistry of Glasses, Chapter 5, P. Hrma. Batch melting reactions. Chapman & Hall
10. 10. R. Beerkens, Modular melting. Amer. Cer. Soc. Bull. 73 (2004), (7), 35 .
11. 11. L. Nemec, P. Cincibusova, Glass Technol.: Eur. J. Glass Sci. Technol. A 53 (2012) 279-286 .
12. 12. M. Polak, L. Nemec, J. Non-Cryst. Solids 357 (2011) 3108-3116. https://doi.Org/10.1016/i.inoncrysol.2011.04.020
13. 13. M. Polak, L. Nemec, J. Non-Cryst. Solids 358 (2012) 1210-1216. https://doi.Org/10.1016/i.inoncrysol.2012.02.021
14. 14. P. Cincibusova, L. Nemec, Glass Technol.: Eur. J. Glass Sci. Technol. A 53 (2012) 150-157 .
15. 15. M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Sklafska tavici pec pro kontinuälni taveni skel rizenou konvekci. CZ patent 304 703 (2012) .
16. 16. M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Způsob kontinualniho taveni skel rizenou konvekci skloviny. CZ patent 304 432 (2012) .
17. 17. M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Method for continuous glass melting under controlled convection of glass melt and glass melting fumace for making the same.WO 2014/ 036 979 A1 (2013) .
18. 18. L . Nemec, L. Hrbek, M. Jebava, J. Brada: Tavici prostor kontimualni tavici pece. CZ 31 123 U (2017) .
19. 19. L. Nemec, L. Hrbek, M. Jebava, J. Brada: Tavici prostor kontimualni sklafske tavici pece a zpüsob taveni skla v tomto prostoru. CZ 307 659 (2017) .
20. 20. L. Nemec, L. Hrbek, M. Jebava, J. Brada: Schmelzraum eines kontinuierliches Glasschmelzofens und nach einem darin aufgeführten Verfahren erhaltene Glasschmelze. DE 20 2018 105 160 U1 (2019) .
21. 21. L. Nemec, L. Hrbek, M. Jebava, J. Brada: Schmelzraum eines kontinuierliches Glasschmelzofens und nach einem darin aufgeführten Verfahren erhaltene Glasschmelze. DE 10 2018 122 017 A9 (2019) .

bibliography

1. 1. L. Nèmec, P. Cincibusova, Ceramics-Silikaty 53 (2009) 145-155 .
2. 2. L. Nemec, P. Cincibusova, Ceramics-Silikaty 52 (2008) 240-249 .
3. 3. M. Jebava, L. Nemec, Ceramics-Silikaty 62 (2018) 86-96. https://doi.org/10.13168/cs.2017.0049
4. 4th L. Hrbek, M. Jebava, L. Nemec, J. Non-Cryst. Solids 482 (2018) 30-39. https://doi.Org/10.1016/i.inoncrysol.2017.12.009
5. 5. W. Trier: Glass melting furnaces. Springer-Verlag, Berlin, Heidelberg, New York, Tokyo 1984 .
6. 6th A. Smrcek a kol .: Taveni skla, Ceska sklafska spolecnost os Jablonec nad Nisou 2008, str. 280 .
7. 7th Z. Zhiquiang, Y. Zhihao. Basic flow pattern and its variation in different types in glass tank furnaces, Glast. Ber. Glass Sci. Technol. 70 (1997), (6) 165-172 .
8. 8th. J. Stanek: Elektricke taveni skla, SNTL Praha 1986 .
9. 9. A. Paul: Chemistry of Glasses, Chapter 5, P. Hrma. Batch melting reactions. Chapman & Hall
10. 10. R. Beerkens, Modular melting. Amer. Cerium. Soc. Bull. 73 (2004), (7), 35 .
11. 11. L. Nemec, P. Cincibusova, Glass Technol .: Eur. J. Glass Sci. Technol. A 53 (2012) 279-286 .
12. 12th M. Polak, L. Nemec, J. Non-Cryst. Solids 357 (2011) 3108-3116. https://doi.Org/10.1016/i.inoncrysol.2011.04.020
13. 13th M. Polak, L. Nemec, J. Non-Cryst. Solids 358 (2012) 1210-1216. https://doi.Org/10.1016/i.inoncrysol.2012.02.021
14. 14th P. Cincibusova, L. Nemec, Glass Technol .: Eur. J. Glass Sci. Technol. A 53 (2012) 150-157 .
15. 15th M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Sklafska tavici pec pro continuälni taveni skel rizenou konvekci. CZ patent 304 703 (2012) .
16. 16. M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Způsob kontinualniho taveni skel rizenou konvekci skloviny. CZ patent 304 432 (2012) .
17. 17th M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Method for continuous glass melting under controlled convection of glass melt and glass melting fumace for making the same. WO 2014/036 979 A1 (2013) .
18. 18. L . Nemec, L. Hrbek, M. Jebava, J. Brada: Tavici prostor kontimualni tavici pece. CZ 31 123 U (2017) .
19. 19th L. Nemec, L. Hrbek, M. Jebava, J. Brada: Tavici prostor kontimualni sklafske tavici pece a zpüsob taveni skla v tomto prostoru. CZ 307 659 (2017) .
20. 20th L. Nemec, L. Hrbek, M. Jebava, J. Brada: Melting chamber of a continuous glass melting furnace and glass melt obtained by a method listed therein. DE 20 2018 105 160 U1 (2019) .
21. 21st L. Nemec, L. Hrbek, M. Jebava, J. Brada: Melting chamber of a continuous glass melting furnace and glass melt obtained by a method listed therein. DE 10 2018 122 017 A9 (2019) .

QUOTES INCLUDED IN THE DESCRIPTION

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Non-patent literature cited

• L. Nèmec, P. Cincibusova, Ceramics-Silikaty 53 (2009) 145-155 [0066]
• L. Nemec, P. Cincibusova, Ceramics-Silikaty 52 (2008) 240-249 [0066]
• M. Jebava, L. Nemec, Ceramics-Silikaty 62 (2018) 86-96. https://doi.org/10.13168/cs.2017.0049 [0066]
• L. Hrbek, M. Jebava, L. Nemec, J. Non-Cryst. Solids 482 (2018) 30-39. https://doi.Org/10.1016/i.inoncrysol.2017.12.009 [0066]
• W. Trier: Glass melting furnaces. Springer-Verlag, Berlin, Heidelberg, New York, Tokyo 1984 [0066]
• A. Smrcek a kol .: Taveni skla, Ceska sklafska spolecnost o.s. Jablonec nad Nisou 2008, str. 280 [0066]
• Z. Zhiquiang, Y. Zhihao. Basic flow pattern and its variation in different types in glass tank furnaces, Glast. Ber. Glass Sci. Technol. 70 (1997), (6) 165-172 [0066]
• J. Stanek: Elektricke taveni skla, SNTL Praha 1986 [0066]
• A. Paul: Chemistry of Glasses, Chapter 5, P. Hrma. Batch melting reactions. Chapman & Hall [0066]
• R. Beerkens, Modular melting. Amer. Cerium. Soc. Bull. 73 (2004), (7), 35 [0066]
• L. Nemec, P. Cincibusova, Glass Technol .: Eur. J. Glass Sci. Technol. A 53 (2012) 279-286 [0066]
• M. Polak, L. Nemec, J. Non-Cryst. Solids 357 (2011) 3108-3116. https://doi.Org/10.1016/i.inoncrysol.2011.04.020 [0066]
• M. Polak, L. Nemec, J. Non-Cryst. Solids 358 (2012) 1210-1216. https://doi.Org/10.1016/i.inoncrysol.2012.02.021 [0066]
• P. Cincibusova, L. Nemec, Glass Technol .: Eur. J. Glass Sci. Technol. A 53 (2012) 150-157 [0066]
• M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Sklafska tavici pec pro continuälni taveni skel rizenou konvekci. CZ patent 304 703 (2012) [0066]
• M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Způsob kontinualniho taveni skel rizenou konvekci skloviny. CZ patent 304 432 (2012) [0066]
• M. Polak, L. Nemec, P. Cincibusova, M. Jebava, J. Brada, M. Trochta: Method for continuous glass melting under controlled convection of glass melt and glass melting fumace for making the same. WO 2014/036 979 A1 (2013) [0066]
• . Nemec, L. Hrbek, M. Jebava, J. Brada: Tavici prostor kontimualni tavici pece. CZ 31 123 U (2017) [0066]
• L. Nemec, L. Hrbek, M. Jebava, J. Brada: Tavici prostor kontimualni sklafske tavici pece a zpüsob taveni skla v tomto prostoru. CZ 307 659 (2017) [0066]
• L. Nemec, L. Hrbek, M. Jebava, J. Brada: Melting chamber of a continuous glass melting furnace and glass melt obtained by a method listed therein. DE 20 2018 105 160 U1 (2019) [0066]
• L. Nemec, L. Hrbek, M. Jebava, J. Brada: Melting chamber of a continuous glass melting furnace and glass melt obtained by a method listed therein. DE 10 2018 122 017 A9 (2019) [0066]

Claims (7)

Glass melting furnace with the conversion region (1) for converting the glass batch (5) into glass melt (13) comprises: the conversion region (1) with the layer of the glass mixture (5) on the molten glass melt (13), which is the bottom (7), the opposite side walls (10 and the front side (14), is provided with two side entrances (2) and is heated with heating electrodes (3) and gas burners (4); and the conversion region (1) is followed by the homogenization region (6), which is heated fully electrically for the homogenization of the glass melt (13) and is characterized in that the conversion region (1): a) has a side entrance (2) on each opposite side wall (10); b) is equipped with vertical rod electrodes (3) placed in the floor (7) and vertical gas burners (4) placed in the vault (8); c) has vertical rod heating electrodes (3) distributed over the entire surface of the floor (7) and gas burners (4) over the entire surface of the vaults (8) in regular formations; d) the axes (9) of the vertical electrodes (3) have a minimum distance of 0.3 m from one another and from the walls (10, 14); e) the axes (11) of the vertical burners (4) have a minimum distance of 0.5 m from one another and from the walls (10, 14); and f) that the tips (12) of the electrodes (3) are a maximum of 0.4 m away from the lower surface of the layer of the glass batch (5). Glass furnace noisy Claim 1 characterized in that the conversion region (1) has a proportion of the electrical energy of the heating electrodes (3) of at least 50% of the total energy supplied to the conversion region (1) with the heating electrodes (3) and the burners (4). Glass melting furnace according to the Claims 1 to 2 characterized in that the vertical heating electrodes (3), the length of which extends directly to the lower surface of the glass batch (5), are rod electrodes (3) made of molybdenum. Glass melting furnace according to the Claims 1 or 2 , is characterized in that the vertical gas heating burners (4) are heated with natural gas together with air or oxygen. Glass melting furnace according to the Claims 1 or 2 , is characterized in that the vertical gas heating burners (4) are heated with hydrogen together with air or oxygen. Glass melting furnace according to the Claims 1 to 5 , is characterized in that the electrodes (3) and the gas burners (4) in the conversion region (1) 6,000 to 14,000 kW for the conversion of the glass batch (5) into the glass melt (13) for the creation of 3 to 7 kg of glass is fed per second. Glass melting furnace according to that Claim 6 , characterized in that the conversion rate of the conversion of the glass batch (5) into molten glass (13) is within a tolerance of 0.25 to 0.30 kg × m ^-2 × s ^-1 .

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