Hybrid electrode and method for producing the same

Abstract

The invention relates to a mixing electrode and a method for producing the same. The mixing electrode according to the invention is intended for use in a glass melting process for heating glass batch material and simultaneously for the pressurized gas introduction into the batch material to ensure the optimum mixing of the molten glass batch material in the furnace. The electrode according to the invention comprises a body (1) made of an electrically conductive material, which has at least one through-hole (8) extending along the longitudinal axis of the mixing electrode and at least one fluid transport channel (7) to force the molten glass to move by the flow of gas bubbles. In the at least one through-hole (8), at least one filling element (2) is arranged, which partially reduces the cross-sectional area of the through-hole (8), wherein the at least one fluid transport channel (7) is formed between the body (1) and the filling element (2) and / or between at least two filling elements (2).

Description

Technical Field

[0001] This invention relates to a hybrid electrode and a method for producing the same. The hybrid electrode (also known as an electrode-bubbler) according to the invention is intended for use in glass melting processes to heat glass and simultaneously introduce a stream of bubbles into the glass under pressure. The bubbles are then directed toward a batch layer floating on the surface to ensure accelerated heating, melting of the batch, and homogenization with the molten glass in the furnace. Background Technology

[0002] US3305340 discloses a structure for a molybdenum electrode-bubbler with a diameter of 3 inches (76.2 mm), including a central hole with a larger diameter (2 inches, or 50.8 mm) and channels with smaller diameters (1 / 32 to 1 / 8 inch, or 0.8 to 3.2 mm) extending radially and obliquely downward from the central hole.

[0003] EP 3647280 A1 discloses a structure for a two- or three-element electrode-bubbler, wherein gas is transported through one or more channels coaxially arranged within a ceramic rod. The diameter of the gas transport channels in the electrode-bubbler ceramic core is no greater than 1 mm, preferably less than 0.5 mm. These channels are formed during the ceramic forming stage.

[0004] EP 270518 A2 discloses a structure for a multi-segment bubbler with a ceramic core having a system of directional holes or channels for gas flow, oriented parallel to the longitudinal axis of the bubbler. To extend the life of the bubbler, a gap is left between the outer surface of the core with the gas delivery channels and the inner surface of its ceramic liner, into which pressurized refrigerant is injected.

[0005] However, the design of hybrid electrodes still requires continuous improvement, particularly in ensuring that the gas delivery channels have the smallest possible diameter. Current hole-making techniques (drilling, hollowing out, or forming during core fabrication) do not allow for small-diameter gas delivery channels with relatively large electrode lengths (1.5–2.5 m). Therefore, an alternative method for producing hybrid electrodes is needed that allows for their simple, inexpensive, and reliable production, even with long electrode lengths and small-diameter gas delivery channels. Summary of the Invention

[0006] Unexpectedly, the inventors of this invention have discovered a simple and inexpensive method for producing hybrid electrodes with relatively small-diameter fluid delivery channels that cannot be manufactured by conventional techniques. This method involves inserting at least one filler element with a lateral dimension smaller than that of the through-hole into the through-hole in the hybrid electrode body. This at least one filler element reduces the cross-sectional area of ​​the through-hole and thus creates a smaller fluid delivery channel in the gap between the filler element (its outer surface) and the electrode body (the inner boundary surface of the through-hole) or between the filler elements themselves.

[0007] According to a first aspect of the invention, a mixing electrode for use in a glass melting process is provided, which is in the form of a rod, wherein the body of the mixing electrode is made of a conductive material and has at least one through-hole extending along the longitudinal axis of the mixing electrode and at least one fluid delivery channel to force molten glass to move by a flow of bubbles, wherein at least one filling element is arranged in the at least one through-hole, the at least one filling element partially reducing the cross-sectional area of ​​the at least one through-hole, and wherein the at least one fluid delivery channel is formed as follows:

[0008] Between the body and the filling element, and / or

[0009] Between at least two filler elements.

[0010] In one embodiment, a plurality of filling elements are arranged in the through-hole, which reduces the cross-sectional area of ​​the through-hole to form a plurality of fluid delivery channels.

[0011] In another embodiment, at least two filling elements are arranged one after another along the substantially entire length of the through-hole.

[0012] In another embodiment, at least two filling elements are arranged one on top of the other along the substantially entire length of the through-hole.

[0013] In another embodiment, at least two filling elements are arranged one in front of the other along the substantially entire length of the through-hole.

[0014] At least one filling element may have a polygonal or circular cross-section.

[0015] In one embodiment, at least one longitudinal groove is disposed on at least one of the inner surface of the body and the outer surface of at least one filling element, and the longitudinal groove forms at least one fluid delivery channel after the at least one filling element is inserted into the through hole of the body.

[0016] In yet another embodiment, at least one groove extends parallel to the longitudinal axis of the hybrid electrode.

[0017] In yet another embodiment, at least one groove is spirally shaped around the longitudinal axis of the hybrid electrode.

[0018] In yet another embodiment, at least one groove has a cross-section selected from semicircular, square, rectangular, triangular, elliptical, and trapezoidal sections.

[0019] Preferably, the cross-section of at least one groove is between 0.05 and 64 mm. 2 And more preferably 0.05 to 0.6 mm 2 .

[0020] In another embodiment, a plurality of grooves are arranged on the outer surface of at least one filling element such that when at least one filling element is inserted into a through-hole in the body, they form a fluid delivery channel system.

[0021] In yet another embodiment, on at least one surface selected from the following:

[0022] - The inner surface of the main body,

[0023] - The outer surface of at least one intermediate cylindrical filling element,

[0024] - The inner surface of at least one intermediate cylindrical filling element,

[0025] - The outer surface of at least one filling element, which is disposed inside at least one intermediate filling element and has a solid cross-section.

[0026] At least one groove is arranged to form a fluid delivery channel when at least one filling element and at least one intermediate filling element are inserted into the through hole of the body.

[0027] According to a second aspect of the invention, a method is provided for producing a hybrid electrode for use in a glass melting process, the hybrid electrode being in the form of a rod, the body of the hybrid electrode being made of a conductive material and having at least one through-hole extending along the longitudinal axis of the hybrid electrode, wherein on at least one surface selected from:

[0028] - The inner surface of the main body,

[0029] - Fill the outer surface of the component,

[0030] Manufacture at least one groove extending along the entire length of the filling element and / or body.

[0031] Then the filling element is inserted into the through hole of the body, such that at least one groove forms a fluid delivery channel.

[0032] The hybrid electrode of this invention is used to heat the molten medium, primarily glass, with Joule heating, and simultaneously to agitate it with a stream of hot bubbles released from its tip. This allows for a very wide range of influences on the furnace batch at all stages of the process, during the transformation of the furnace batch into melt.

[0033] In particular, a mixing electrode with a fluid delivery channel of 0.05 to 64 mm is a very useful tool. 2 Within the range, and especially in the range of 0.05 to 0.6 mm 2 The cross-sectional area of ​​a single channel within the range is used to monitor and control the melting process in furnaces that use electricity as the sole energy source and in furnaces designed to use heat from the combustion of gas or oil above the surface of the batch as the sole or primary energy source, where most of the energy (even up to 60%) is or can be provided by electrodes mounted at the bottom of the furnace.

[0034] The hybrid electrode of the present invention can be made of any material used as a standard electrode that does not have a mixing function, and can be installed in a melting furnace (mainly a glass furnace) in place of standard molybdenum electrodes, austenitic nickel-chromium superalloys (so-called Inconel), SNO2, graphite electrodes, and electrodes made of any other material in all their design variations (also known as twisted segments) and applications.

[0035] By using the concept of filling through-holes with filler elements, the cross-sectional area of ​​the through-holes is reduced, thereby forming smaller fluid delivery channels. Therefore, the method for producing hybrid electrodes allows overcoming the technical limitations associated with drilling or hollowing out holes or forming them during the molding process. In particular, the method according to the invention allows for the production of electrodes with multiple small-diameter (less than 0.5 mm) fluid delivery channels in long-length electrodes (up to 3 m and above). This method is not only easier and cheaper to implement than previously used techniques for creating fluid delivery channels, but also ensures the manufacture of electrodes with channel parameters (small diameter, small distance between channels, channels extending in patterns other than straight lines, such as helical systems), which were previously impossible to produce. Attached Figure Description

[0036] The object of the invention is shown in the embodiments in the accompanying drawings, wherein:

[0037] Figure 1 A side view of a hybrid electrode according to an embodiment of the present invention is shown;

[0038] Figure 2 A longitudinal cross-section of a hybrid electrode according to an embodiment of the present invention is shown;

[0039] Figure 3 It shows Figure 2 Detail B in the text;

[0040] Figure 4 A partial side view of a variant of an embodiment of a filling element having a longitudinal groove according to the present invention is shown;

[0041] Figure 5 A partial side view of another variant of the filling element with a spiral groove according to the present invention is shown;

[0042] Figure 6 A side view of another variant of the filling element according to the invention, which has a different cross-sectional shape but no groove, is shown;

[0043] Figures 7-12 Cross-sections of different variations of the hybrid electrode according to the invention are shown in embodiments with filling elements of different shapes;

[0044] Figures 13-20 Cross-sections of different variations of the hybrid electrode according to the invention are shown in an embodiment having a filling element in a through hole and a groove forming a fluid delivery channel.

[0045] Figures 21-28 Cross-sections of different variants of the hybrid electrode according to the invention are shown in embodiments where at least two filling elements are arranged in one of the embodiments with and without grooves.

[0046] Figures 29-32 It was shown that at 0.4 l / min ( Figure 30 ), 1.2 l / min Figure 31 ) and 2.0 l / min ( Figure 32 At a gas flow rate of ), compared with a standard electrode ( Figure 29 The vertical velocity and temperature distribution vectors in the melt near the hybrid electrode of the present invention;

[0047] Figure 33 The average rate of sand particle dissolution in the melting zone of the glass furnace near the electrode is shown as a function of the gas flow rate through the mixing electrode of the present invention (for a flow rate of 0 l / min, this is compared to a standard electrode).

[0048] Figure 34a , Figure 35a and Figure 36a The distribution of batch concentration in the melting zone of a glass furnace is shown in the layers 1 cm below the glass surface, 10 cm below the glass surface, and at the level of the electrode tip, respectively.

[0049] Figure 34b , Figure 35b and Figure 36bThe distribution of batch concentration in the melting zone of a glass furnace is shown in the layer 1 cm below the glass surface, the layer 10 cm below the glass surface, and the layer at the level of the electrode tip, respectively.

[0050] Figures 37-40 It was shown that at 0.4 l / min ( Figure 38 ), 1.2 l / min Figure 39 ) and 2.0 l / min ( Figure 40 At a gas flow rate of ), compared with a standard electrode ( Figure 37 The vertical velocity and temperature distribution vectors within the barrier boosting plane in front of the clarification zone near the hybrid electrode of the present invention;

[0051] Figure 41 The average diameter of bubbles in the layer below the glass / combustion surface above the barrier flux in front of the glass furnace clarification zone near the electrode is shown as a function of the gas flow rate through the mixing electrode of the present invention (for a flow rate value of 0 l / min, this is a comparison standard electrode). Detailed Implementation

[0052] The hybrid electrode in the preferred embodiment of the present invention is typically in Figures 1-3 As shown in the figure, the mixing electrode has the form of a rod or a thick-walled cylinder with a through-hole 8 formed in the body 1. The body 1 of the mixing electrode is made of a conductive material. The through-hole 8 extends along the longitudinal axis of the body 1 over its entire length. A filling element 2 is arranged in the through-hole 8, which restricts its cross-sectional area, thereby creating at least one fluid delivery channel 7 with a smaller cross-sectional area and a smaller diameter. The fluid delivery channel 7 also typically extends over the entire length of the body 1 and is used to introduce a flow of bubbles into the molten glass to force it to move.

[0053] like Figure 2 As shown, it illustrates Figure 2 In detail B, the longitudinal section shows that the end of the filling element 2 is fitted with a short tube 4, and the short tube 4 is fitted with a nut 6. The mixing electrode is connected to the gas supply system via the nut 6. The mixing electrode is connected to the AC power supply in the same manner as the standard electrode (the electrical connection system is not within the scope of this invention). The main conductive component of the mixing electrode of this invention is the body 1.

[0054] Figures 4-6 Three variations of filler element 2 are shown. More specifically, Figure 4 A partial side view of a first variant of the filling element 2 is shown, wherein the groove 3 extends parallel to the longitudinal axis of the mixing electrode. Figure 5A partial side view of a second variant of the filling element 2 is then shown, in which the groove 3 is spirally shaped around the longitudinal axis of the mixing electrode. Furthermore, Figure 6 A partial side view of a variation of a filling element with a groove of no different cross-sectional shape is shown, with an exemplary shape in... Figures 7-12 As shown in the image.

[0055] The filling element 2 preferably extends along the entire length of the through-hole 8. Preferably, multiple filling elements 2 can be disposed within the through-hole 8, arranged such that multiple longitudinal fluid delivery channels 7 are formed between the filling elements 2 and / or between the filling elements 2 and the body 1 (at the inner surface boundary of the through-hole 8). For example, filling elements 2 of the same or different shapes and sizes can be arranged parallel to each other, one on top of the other, or one in the other (e.g., concentrically). Preferably, the filling element 2 is longer than the body 1 and protrudes from one or both sides of the through-hole 8, which facilitates connection to the gas connector. For example, the filling element 2 can be at least 30 mm longer than the body 1 of the mixing electrode, and preferably at least 50 mm longer.

[0056] The filling element 2 can be made of, for example, the same material as the electrode body, namely molybdenum, austenitic nickel-chromium superalloy (so-called Inconel), SnO2, graphite, platinum, etc.

[0057] The delivery channel 7 is configured to deliver gas and liquid. The fluid delivery channel 7 is used to introduce a flow of bubbles into the molten glass to stimulate its movement, for example, bubbles directly from the gas delivered through the through-hole 8 or from the evaporation of the liquid delivered through the through-hole 8.

[0058] Figures 7-12 Cross-sections of various embodiments of hybrid electrodes with filling elements 2 of different shapes are shown. The filling element 2 may, for example, have a circular (circular, oval, elliptical, or similar shape) or polygonal (e.g., triangular, quadrilateral, etc.) cross-section. Therefore, Figure 7 A hybrid electrode with a filling element 2 having a circular cross-section is shown, which is arranged coaxially in a through-hole 8. Figure 8 It shows the relationship with Figure 7 The same filling element is arranged non-coaxially in the through hole 8 (its central axis is laterally offset relative to the longitudinal axis of the hybrid electrode). Figure 9 A filling element 2 with a square cross-section is shown. Figure 10 A hexagon is shown. Figure 11 A hybrid electrode with multiple circular filling elements 2 is shown, and Figure 12 A hybrid electrode with multiple octagonal filling elements is shown.

[0059] Figures 13-20Cross-sections of various embodiments of the hybrid electrode of the present invention are shown, having a groove 3 formed on the outer surface of the filling element 2, which serves as a fluid delivery channel 7, wherein in Figure 13 In the middle, the groove 3 formed on the outer surface of the core 2 has a semi-circular cross-section. Figure 14 The middle part is a rectangle, in Figure 15 and Figure 16 The center is a square, in which Figure 16 A variant with four through holes 8 is shown. Figure 17 The middle part is a triangle, in Figure 18 The middle part is oval, and in Figure 19 The middle part is trapezoidal. In all these variations, the outlet of the fluid delivery channel 7 forms a single ring with an outlet orifice at the top of the mixing electrode. Furthermore, Figure 20 An embodiment is shown in which the groove 3 with a rectangular cross-section is not formed on the filling element 2, but on the inner surface of the body 1.

[0060] The groove 3 can preferably extend longitudinally or spirally, such as Figure 4 and Figure 5 As shown. Another possible extension of the groove is also possible.

[0061] Figures 21-28 Other embodiments of the hybrid electrode are shown, wherein at least two filling elements 2 are arranged one in front of the other, i.e., concentric or substantially concentric. In these embodiments, at least one filling element 2 (identified by reference numeral 5 for simplicity) is referred to as an intermediate filling element and is in the form of a cylinder or a tube.

[0062] Figures 21-27 Cross-sections of various variations of the electrode of the present invention are shown, having grooves 3 formed in the filling element 2 and the intermediate filling element 5, wherein... Figure 21 In the middle, the groove 3 formed in the outer surface of the filling element 2 and the outer surface of the intermediate filling element 5 has a semi-circular cross-section. Figure 22 The middle part is rectangular (in this example, the through hole is not coaxial with the central axis of the body 1), in Figure 23 and Figure 24 The center is a square, in Figure 25 The middle part is a triangle, in Figure 26 The middle part is oval, and in Figure 27 The middle part is trapezoidal. In all these variations, the outlet of the fluid delivery channel 7 forms two concentric rings at the tip of the mixing electrode to create an outlet orifice.

[0063] according to Figures 21-27 In the embodiment, the grooves 3 on the outer surfaces of the filling element 2 and the intermediate filling element 5 can be aligned with... Figure 4 and Figure 5They are made in a similar manner to those shown, meaning they can extend parallel to the longitudinal axis of the hybrid electrode or spirally extend around the longitudinal axis of the hybrid electrode.

[0064] Figure 28 Another embodiment without the groove 3 is presented, wherein the two filling elements 2 and 5 are arranged coaxially, one in the other, such that the fluid delivery channel 7 is formed in the gap between the intermediate filling element 5 and the body 1, and in the gap between the filling element 2 and the intermediate filling element 5.

[0065] The outer diameter of the hybrid electrode of the present invention can be any value, but preferably it adopts the same value as the diameter of a standard electrode (e.g., a molybdenum electrode), i.e., 1.5 inches (3.81 cm), 2 inches (5.08 cm), 2.5 inches (6.35 cm), or 3 inches (7.62 cm). In this embodiment variant, the hybrid electrode of the present invention is compatible with commercially available electrode holders (coolers) (holder-cooler designs are not within the scope of the present invention) and can be installed in existing furnaces.

[0066] The groove 3 can be obtained by any surface treatment technique, including machining (including milling, turning, and boring), laser beam cutting, or high-pressure liquid jet cutting, with the optional addition of abrasive. The groove 3 can also be formed during the formation of the body 1, the filling element 2, and the intermediate filling element 5, for example by using a suitable nozzle in extrusion.

[0067] Using milling technology, the groove 3 can be obtained, and after assembling the components of the hybrid electrode of the present invention, the groove 3 forms a cross-sectional area of ​​less than 0.1 mm. 2 (This corresponds to a rectangular cross-section of 0.2 x 0.5 mm) and is even less than 0.05 mm. 2 The fluid transport channel (corresponding to a semi-circular cross-section with a diameter of 0.25 mm) is not determined by the technical possibilities of the forming groove 3, but by the requirement that the mixing electrode will not be blocked by the melt when the gas stops flowing.

[0068] The maximum safe cross-sectional dimensions (diameter and surface area) of the fluid transport channel 7 depend on the wetting angle of the specific electrode material with the specific melt at the electrode operating temperature and the distance from the electrode tip to its cooler. For exposure in glass at a height of 500-800 mm, at 1200-1500 mm... o For sodium silicate-calcium glass and molybdenum electrodes operating at temperature C, the safe cross-sectional area of ​​a single gas outlet (the cross-section of the fluid delivery channel directly located at the gas outlet, i.e., at the tip of the mixing electrode), i.e., the cross-sectional area protecting the mixing electrode from irreversible blockage in the event of a 1-hour gas flow cessation, is approximately 0.4–0.6 mm².2 Its diameter corresponds to a circular opening of approximately 0.7 mm.

[0069] The outer diameter range of the filling element 2 (and intermediate filling element 5) matches the outer diameter of the body 1, i.e., the outer diameter of the mixing electrode. Typically, it is assumed that the larger diameter of the single or multiple rings formed by the outlet holes of the fluid delivery channels at the electrode tip is formed by a larger number of grooves 3 with small cross-sections (forming the fluid delivery channels 7 after assembling the components of the mixing electrode), providing a wider range of possible influences on the molten batch and giving more control options for the various stages of the raw material batch's transformation into the melt.

[0070] In certain embodiments, although the hybrid electrode may be provided with only one fluid delivery channel 7, the recommended number of fluid delivery channels 7 in a single hybrid electrode of the present invention is at least three, and preferably between ten and twenty.

[0071] The recommended distance between the outer edges of the outlet openings of adjacent fluid delivery channels 7 should be about 1 mm, although smaller and larger distances are both applicable and will not impede or limit the possibility of producing hybrid electrodes using the methods described in this application.

[0072] The hybrid electrode of the present invention is provided with a fluid delivery channel 7, wherein the cross-sectional area of ​​a single groove 3 is 0.05 to 0.64 mm. 2 And preferably 0.05 to 0.6 mm 2 It can be operated at gas flow rates from 0.1 l / min to up to 5 l / min, although the recommended preferred flow rate range for use in glass furnaces is from about 0.2 to about 2.0 l / min, which is necessary to accelerate the mixing process of cold batches with glass, or to accelerate the dissolution of sand or the growth of bubbles during the clarification process.

[0073] The hybrid electrodes of this invention are mounted vertically or at an angle on the bottom of the furnace or on a dedicated support. The hybrid electrodes can operate independently in single pairs or in a coordinated manner in a linear system or other geometric configuration. The hybrid electrodes of this invention can be used in furnaces where electricity is the sole (exclusive) source of melting energy, or in furnaces where electricity is combined with other energy sources for melting the batch, wherein the proportion of electricity used in the furnace can be in any proportion to the proportion of energy from other sources.

[0074] A particular application of the hybrid electrode of the present invention is in a glass furnace, the structure of which is configured to use the heat from the combustion of gas or oil above the surface of the batch as the sole or primary energy source, wherein, depending on the selected operating mode, a large portion of the energy (up to 60%) is supplied by an electrode mounted at the bottom of the furnace, while the firing system provides a supplementary portion of 40% to 100% of the energy.

[0075] Because of the wide range of bubble diameters generated (primarily due to the ability to generate small bubbles with diameters of 1-5 mm) and the wide range of cone diameters of the influence of these bubbles on the glass (primarily the possibility of obtaining large diameters of over 200 mm directly below the glass surface), the hybrid electrodes of the present invention allow for this modification of convection in molten glass, and furnaces equipped with them ensure high-quality products across a wide range of electricity and fuel combustion ratios. Systems based on the hybrid electrodes of the present invention have heating power ranging from several kilowatts to tens of megawatts, most commonly from several hundred kilowatts to approximately 20 megawatts.

[0076] The way the hybrid electrode of this invention affects the molten batch during glass melting:

[0077] To obtain the necessary heating power from Joule heating (sometimes 10 MW or higher), dozens of electrodes are installed at the bottom of a typical furnace for melting packaged glass with a capacity of approximately 400 TPD (tons / day), instead of a few to a dozen or so: 20, 30, or even 60. With such a large number of electrodes and installed power, it is difficult to achieve geometric separation of the operating zones of the melting flux and the barrier flux in the vessel, and (most importantly) it is difficult to obtain positive interactions of convection from various sources.

[0078] In furnaces with a high proportion of power from electric fluxing, upward convection generated by heat released near the electrodes becomes increasingly important. Therefore, with a large share of fluxing power (30-60%), two interdependent convection modes of the glass material operate within the furnace. One mode arises from the presence of so-called high-temperature points (the highest temperature areas within the furnace) on the glass surface, caused by the interaction between the firing system and the barrier fluxing. The second mode originates from the significant energy released by the electrode system, which is installed at the bottom of the melting zone and optionally in the barrier fluxing.

[0079] The first system is characterized by a long-distance, horizontally oriented flow of the molten glass material: a surface flow from the hot spot to the charging zone and a bottom flow in the opposite direction. The glass flowing between the hot spot and the charging zone (melting zone) is separated, or rather, should be separated, from the glass flowing between the hot spot and the channels (clarification and reabsorption zones). The presence of a physical ceramic barrier in the furnace facilitates the separation of these zones, and the barrier is positioned approximately coinciding with the hot spot.

[0080] The significant amount of heat released near the electrodes in the molten zone, particularly in the bottom glass layer at a height of approximately 700 mm, triggers vertical convection, pushing the glass upwards towards the surface covered by the cooler batch. After transferring some of the heat to the batch, the cooled glass block, mixed with unmelted batch residue (primarily undissolved sand particles and bubbles from carbonate decomposition), settles to the bottom.

[0081] This vertical directional flow system is typical of so-called cold top furnaces that use 100% electricity. One of the most important technical challenges associated with glass melting in a cold top furnace is maintaining the vertical arrangement of zones corresponding to the various stages of the melting process: heating the batch, dissolving sand residue, refining and cooling, and homogenization (thermal and chemical), while separating sand dissolution and refining.

[0082] In furnaces equipped with conventional firing systems, most of the energy (30-60%) is supplied by electrodes mounted at the bottom of the ladle. The release of a large amount of heat in the bottom layer of the melting zone reduces the temperature gradient between the charging zone and the hot spot. This reduced temperature gradient results in a weakening of the return flow of the glass material from the hot spot to the charging zone and the bottom flow in the opposite direction. However, the working flow from the hot spot to the channel is not weakened and can even be enhanced if a high-power barrier flux is used.

[0083] The simultaneous occurrence of these two phenomena increases the risk of short circuits, namely the coupling of backflow and workflow. As a result of these couplings, poor-quality glass is directly sucked into the channel from the bottom and / or surface of the melting zone, leading to increased production waste.

[0084] The above description demonstrates that the operational flexibility of furnaces configured to alternate between two energy sources is not only a design challenge but also a technological one. This necessitates the use of new tools to enable efficient glass production under variable extraction parameters, regardless of the proportion of energy from these sources. The hybrid electrode of this invention is equipped with a fluid delivery channel with small-area outlet orifices for implementing a fluxing system in such a furnace, allowing for effective monitoring and control of all stages of the batch-to-glass conversion process.

[0085] Preheating of the batch components is the most energy-intensive stage, and dissolution of the abrasive particles is the most time-consuming phase in the glass melting process. Clarification, i.e., removal of residual bubbles, and chemical and thermal homogenization are the stages that determine the final quality of the glass material at the furnace outlet. Due to the wide range of available combinations of fluxing power and applied gas flow rates, the hybrid electrode system of the present invention allows for parameter adjustment to ensure the most efficient use of the energy released near the electrode to enhance each of these stages.

[0086] In the cold layer of the batch feed zone of the furnace, due to the presence of blocked bubbles and the polycrystalline transformation of quartz to crystalline quartz, its apparent density is lower than that of molten glass, and it floats on its surface.

[0087] In furnaces where energy is supplied solely by heat generated from fuel combustion above the glass and batch surface, the batch layer is primarily heated via heat carried by the hot glass on its lower surface, derived from the recirculation from the highest temperature zone (hot spot) within the furnace, because the thermal conductivity of the batch is very low below 1000°C. This process is slow, which is one reason why the energy consumption of the melting process exceeds thermodynamic results.

[0088] In furnaces equipped with bubbling systems in the melting zone, hot glass can be lifted to the batch layer via forced convection at a rate depending on the gas flow rate and the bubbler geometry. Due to the lack of additional energy, bubblers are not the optimal tool for mixing glass and batch near the charge bag, where the batch layer is relatively thick (10-20 cm) and the temperature remains low. Mixing a large amount of cold batch with glass from the bottom layer that has not been heated by additional heat from the electrode flux results in a significant drop in the local temperature of this part of the tank, thereby slowing down all thermally activated reactions and processes occurring between batch components and between batch components and glass.

[0089] In furnaces equipped with electric flux in the melting zone, some of the energy used to heat the batch is released near the electrodes and further carried to the surface by relatively weak (thermal) convection. With standard electrodes, the continuity of the batch layer cannot be interrupted due to the low velocity (0.2-0.5 mm / s) of the glass in the heating-induced upward convection near the electrodes. In this case, the hot glass mixes with the batch to a very limited extent and exchanges heat primarily with its lower surface. Therefore, a large temperature gradient (over 100°C) is maintained between the upper and lower surfaces of the batch, and further time-consuming heat transfer throughout the batch layer occurs mainly through conduction. Another disadvantage of intensely heating the batch layer without mixing with the hot glass is the formation of foam on the surface. This phenomenon also hinders heat penetration from the combustion space into the glass and leads to the unnecessary loss of some of the clarifying agents already present at this melting stage.

[0090] When the standard electrode in the melting flux system is replaced with an electrode produced using the method of this invention, it is equipped with multiple electrodes having a small cross-sectional area (less than 0.25 mm). 2 0.15 mm is preferred. 2When the mixing electrode is used in the fluid delivery channel, and when a low gas flow rate of 0.4-2 l / min (preferably less than 0.4 l / min) is used, convection much stronger than that obtained by operating a standard electrode is generated, forcing the hot glass to move with a high vertical velocity component. The continuity of the batch layer is interrupted, which allows heat to penetrate better from the combustion space. At a low gas flow rate (not greater than 0.4 l / min) through the mixing electrode, a preferred compromise is achieved: a portion of the batch is mixed with a controlled volume of glass (which accelerates its heating and melting), without causing significant (dangerous) cooling of the resulting mixture.

[0091] Figures 29-32 A detailed comparison of the convection effects generated by the standard electrode and the hybrid electrode of the present invention is shown. Figures 29-32 It was shown that at 0.4 l / min ( Figure 30 ), 1.2 l / min Figure 31 ) and 2.0 l / min ( Figure 32 At a gas flow rate of ), compared with a standard electrode ( Figure 29 ) and the vertical velocity vector and temperature diagram of the melt near the hybrid electrode of the present invention. In the surface layer of the mixture of unmelted batch and glass containing still unmelted sand particles, at a certain distance from the axis set by the axis of the hybrid electrode of the present invention ( Figures 30-32 This creates a preferred mode of localized convection, inducing continuous rotation of the glass material, first counterclockwise and then clockwise. This draws the mixture of unmelted batch and glass containing unmelted abrasive grains into the Joule energy release zone near the electrode surface. Heated by the energy released from the electrodes, the material reverses direction with the rising flow, with a portion re-entering the clockwise rotation. This cycle is repeated multiple times, promoting the rapid dissolution of individual abrasive grains and their aggregates.

[0092] Unlike the preferred mode of convection generated by hybrid electrodes, the standard electrode ( Figure 29 This generates localized convective motions in the glass material, which are poorly coordinated. In the Joule energy release region, two glass rotations can be observed, both clockwise. Because these rotations are in the same direction, only a portion of the heated glass is lifted below the lower surface of the mixture of batch material and glass containing undissolved abrasive particles. Due to the glass's low kinetic energy, it does not penetrate this layer but instead diffuses outward from the axis set by the electrodes below its lower surface until it is hindered by the viscous frictional properties of a liquid such as molten glass.

[0093] The hot glass in the influence zone of the hybrid electrode forms a cone that expands toward the glass surface covered with the batch material layer. The cross-sectional area of ​​this cone, located 1 cm above the upper surface of the hybrid electrode of the present invention, is 4-5 times that of the standard electrode. The hot glass stream reaches the region 1 cm below the upper surface of the batch material at an average velocity of 4.3 (for a gas flow rate of 0.4 l / min) to 8.0 cm / s (for a gas flow rate of 2.0 l / min).

[0094] With the fluxing power adjusted to the unit glass extraction capacity of the furnace, the forced convection velocity obtained at a flow rate of approximately 0.4 l / min allows for controlled mixing of hot glass and cold batch, while maintaining the temperature of the resulting mixture above 1200°C, preferably above 1250°C. At this temperature, the reaction of the sand with the mixture of (mainly) silicates, sodium carbonate, and calcium carbonate proceeds at a sufficient rate, and simultaneously, there is no risk of undissolved sand particles escaping into the refining zone. The hybrid electrode system of the present invention not only provides Joule energy but also improves the efficiency of energy transfer from the combustion space and the overall furnace efficiency through a faster conversion of the batch to glass. Therefore, with the same total energy consumption as a furnace equipped with a standard electrode system, the average glass temperature in the furnace is increased by tens of degrees Celsius. In this way, the fluxing system constructed using the hybrid electrode of the present invention allows for enhanced batch heating in conventional gas furnaces, where the energy share from electric fluxing can reach 60%.

[0095] After the carbonate batch components melt and react with the sand, the process of dissolving the residual sand particles begins. The kinetics of sand dissolution are affected by temperature ([SiO4] in the glass). 4- The diffusion coefficient is temperature-dependent, and factors affecting the thickness of the reaction layer on the sand grain surface and the SiO2 concentration difference between the reaction layer and the base glass in the furnace are controlled. Increased average glass temperature in the furnace equipped with a hybrid electrode system leads to higher SiO2 diffusion coefficients. Model studies also show that, compared to using standard electrodes (25-35%), the volume in the melting vessel (approximately 25-30%) and the surface area of ​​the batch (approximately 20-25%) are smaller, and a larger proportion of sand grains are dissolved in the melting zone equipped with hybrid electrodes. To a large extent, these effects are also due to… Figures 29-32 The double rotation of the glassy material shown leads to the effective removal of the reaction layer from its surface. Therefore, [SiO4] 4- The thickness of the layer diffused from the sand grains into the glass decreases more rapidly, and the difference in SiO2 concentration almost always remains close to its maximum value. Figure 33 The effect of the gas flow rate used in the hybrid electrode on the sand dissolution process is shown, wherein the average rate of sand dissolution in the melting zone near the electrode is presented as a function of the gas flow rate through the hybrid electrode of the present invention.

[0096] Figure 34a , Figure 35a and Figure 36a The concentration distribution of the compound in the standard electrode is shown in the layer 1 cm below the glass surface, the layer 10 cm below the glass surface, and the layer at the level of the electrode tip. Figure 34b , Figure 35b and Figure 36b The corresponding distribution of batch concentration at the same level (i.e., within the same layer) is shown, but it applies to the mixed electrode of the present invention. For example... Figures 34a-36b As shown, the hybrid electrode system of the present invention, through appropriate selection of configuration and adjustment of gas flow rate to the fluxing power used, acts on the batch near the charge bag, increasing the reaction rate of sand with soda and limestone in the early stages of melting, as demonstrated by the significant reduction in batch concentration in the layer 10 cm below the glass surface and in the layer set by the electrode tip. Therefore, the primary melt flowing into other zones of the melting tank contains sand particles with smaller average size residue, which also contributes to its faster and more complete melting in other stages of the glass melting process in the furnace (reducing the sand diameter from 0.2 mm to 0.05 mm accelerates the melting process by approximately 100%). In this way, the glass material flowing into the refining zone has no residue of unmelted sand in many melting cases, and above 3 t / (m³) 2 With a high unit melting efficiency of ∙24h, the size of these residues is less than 0.05 mm and they are completely dissolved during the glass entry channel. This allows for the production of glass containing less than 50 bubbles with a diameter of 0.7 mm per 100 grams, preferably less than 30 bubbles with a diameter of 0.7 mm per 100 grams.

[0097] The physical support for the clarification process is based on the combined effect of two factors: temperature rise and strong glass-rising convection. Figures 37-40 The hybrid electrode of the present invention is shown, particularly when using a gas flow rate in the range of 1.2-2.0 l / min. Figure 39 and Figure 40 (Separately) Ensure that these two conditions are met: at the electrode tip (500 mm above the bottom of the furnace), the glass reaches a temperature above 1450°C, and the upward convection velocity in the cylinder with an electrode diameter of approximately 65-76 mm is 50 cm / s. The inverted cone that lifts the glass to the surface reaches a diameter of approximately 1 m, and the glass reaches the edge of the circle at a velocity of approximately 12 cm / s.

[0098] Furthermore, unlike standard electrodes, the hybrid electrodes of this invention create a tight barrier by generating precise motion on the glass flow stimulated by the working flow. For standard electrodes, the vertical velocity component generated by thermal convection around them is too weak to break the dominance of the working flow. This difference has a significant impact on the course of the clarification process.

[0099] When the barrier is constructed using the hybrid electrode of the present invention, wherein the gas flow rate is 1.2 l / min, the average diameter of the bubbles in the 20 cm glass layer directly below the surface is 1276 micrometers, and their concentration is 72382 bubbles / kg, which translates to 11.255 m³ of gas released from the surface. 3 / h gas surface flow, see Figure 41 .

[0100] When the barrier is constructed using a standard electrode (i.e., without mixing function), the average diameter of bubbles in the glass layer 20 cm directly below the surface is 785 micrometers, and their concentration is 125,067 bubbles / kg, which translates to 7.383 m³ of vapor released from the surface. 3 / h of gas surface flow. The average bubble size increased by 62.4%, the bubble concentration in the surface layer decreased by 42.1%, and the gas surface flow released from the surface increased by 52.4%, indicating that the hybrid electrode of the present invention has very high efficiency in enhancing the clarification process, especially under high melting efficiency.

[0101] The hybrid electrode of this invention significantly accelerates the refining process due to the thermal support of the diffusion of refining gases (typically SO2 and O2) onto the fine bubbles (mainly CO2) remaining in the glass material after the melting process. In a cylinder with a diameter approximately three times that of the electrode, the glass velocity is not less than 10 cm / s. For gas flow rates in the range of 1.2–2.0 l / min, the glass is linearly lifted to the glass surface by this flow without interference from the upper surface of the electrode. Furthermore, due to Joule heat release, glass in the layer located below the electrode tip is drawn into this flow (see...). Figures 38-40 ).

[0102] Standard electrodes offer far less support for the clarification process. The thermal convection generated by these electrodes is too weak to bring glass with bubbles to the surface. At a distance of approximately 250–300 mm from the surface, this flow is impeded, and the orientation of the glass material changes from vertically upward to almost horizontal. Consequently, unclarified glass accumulates in this area, which can then be drawn into the channel by the working flow.

Claims

1. A hybrid electrode for use in glass melting, in the form of a rod, having a body (1) made of a conductive material, having at least one through-hole (8) extending along the longitudinal axis of the hybrid electrode, and at least one fluid delivery channel (7) to force molten glass to move by a flow of air bubbles, characterized in that, At least one filling element (2) is arranged in the at least one through hole (8), the at least one filling element partially reducing the cross-sectional area of ​​the at least one through hole (8), wherein at least one fluid delivery channel (7) is formed between the body (1) and the filling element (2) and / or between at least two filling elements (2).

2. The electrode according to claim 1, wherein, Multiple filling elements (2) are arranged in the through hole (8) to reduce the cross-sectional area of ​​the through hole (8) to form multiple fluid delivery channels (7).

3. The electrode according to claim 1 or 2, wherein, At least two filling elements (2) are arranged one after another along the substantially entire length of the through hole (8).

4. The electrode according to claim 1 or 2, wherein, At least two filling elements (2) are arranged one on top of the other along the substantially entire length of the through hole (8).

5. The electrode according to claim 1 or 2, wherein, At least two filling elements (2) are arranged one in the other along the substantially entire length of the through hole (8).

6. The electrode according to any one of claims 1 to 5, wherein, The at least one filling element (2) has a polygonal cross-section.

7. The electrode according to any one of claims 1 to 5, wherein, The at least one filling element (2) has a circular cross-section.

8. The electrode according to any one of claims 1 to 7, wherein, At least one longitudinal groove (3) is arranged on at least one of the inner surface of the body (1) and the outer surface of the at least one filling element (2), and the at least one longitudinal groove forms the at least one fluid delivery channel (7) after the at least one filling element (2) is inserted into the through hole (8) of the body.

9. The hybrid electrode according to claim 8, wherein, The at least one groove (3) extends parallel to the longitudinal axis of the hybrid electrode.

10. The hybrid electrode according to claim 8, wherein, The at least one groove (3) is spiral-shaped around the longitudinal axis of the hybrid electrode.

11. The hybrid electrode according to any one of claims 8 to 10, wherein, The at least one groove (3) has a cross section selected from semicircular, square, rectangular, triangular, elliptical and trapezoidal sections.

12. The hybrid electrode according to any one of claims 8 to 11, wherein, The cross-section of the at least one groove (3) is 0.05 to 64 mm. 2 And more preferably 0.05 to 0.6 mm. 2 .

13. The hybrid electrode according to any one of claims 8 to 12, wherein, Multiple grooves (3) are arranged on the outer surface of the at least one filling element (2) such that when the at least one filling element (2) is inserted into the through hole (8) of the body (1), they form a fluid delivery channel (7) system.

14. The hybrid electrode according to any one of claims 1 to 13, wherein, On at least one of the following surfaces: - The inner surface of the main body (1), - The outer surface of at least one intermediate cylindrical filling element (5), - The inner surface of at least one intermediate cylindrical filling element (5), - The outer surface of the at least one filling element (2), which is disposed inside the at least one intermediate filling element (5) and has a solid cross-section, The at least one groove (3) is arranged such that when the at least one filling element (2) and the at least one intermediate cylindrical filling element (5) are inserted into the through hole (8) of the body (1), the at least one groove constitutes the fluid delivery channel (7).

15. A method for producing a hybrid electrode for use in a glass melting process, the hybrid electrode being in the form of a rod having a body (1) made of a conductive material and having at least one through-hole (8) extending along the longitudinal axis of the hybrid electrode, characterized in that, On at least one of the following surfaces: - The inner surface of the main body (1), - Fill the outer surface of element (2), At least one groove (3) is formed extending along the entire length of the filling element (2) and / or the body (1). Then the filling element (2) is inserted into the through hole (8) of the body (1), such that the at least one groove (3) forms a fluid delivery channel (7).

Images