Method for determining batch thickness in all-electric glass furnace

Abstract

The invention relates to a method for acquiring and analyzing data relating to batch layers and / or glass melts in an all-electric cold-top melting tank for melting glass, and to the use of the method in a glass manufacturing method.

Description

Technical Field

[0001] This invention relates to a method for collecting and analyzing data about batch layers and / or glass melt, particularly in an all-electric cold-top melting bath for molten glass, and the use of this method in glass manufacturing processes. Background Technology

[0002] To reduce carbon dioxide emissions in glass production, all-electric melting baths are increasingly being used to manufacture glass and glass ceramics.

[0003] In an all-electric melting furnace, the entire free surface of the molten glass is typically covered by a batch layer. This enclosed batch layer thermally insulates the molten glass from the furnace superstructure, thereby reducing the surface temperature of the molten glass from approximately 1400°C to 1650°C to approximately 200°C to 400°C. This maximizes melting capacity and significantly improves the energy efficiency of the melting furnace. Furthermore, the significantly cooler furnace superstructure reduces the risks associated with equipment within the superstructure (such as charging machines) and the materials used in the superstructure, and also lowers the thermal load requirements for the superstructure design.

[0004] Therefore, when operating an all-electric melting bath, measures are typically taken to ensure the formation of a closed batch layer across the entire surface of the molten pool. This is achieved by locally measuring the thickness of the batch layer and adjusting the batch feed accordingly.

[0005] The batch thickness at a specific point (in both time and space) can be manually determined by probing with a rod through the side feed port. However, this method poses risks to personnel and processes when the electric bath heating is on, and requires significant manpower. Furthermore, it only provides localized and relatively imprecise measurements of the batch thickness at a single location.

[0006] Since the temperature of the batch layer depends on its thickness, the thickness can be determined based on the measured temperature. WO 8002833 and US 3980460 describe movable feeding machines for cold-top tanks, in which infrared or thermal sensors measure the temperature of the batch layer. If the temperature of the batch layer is detected to be too high at a certain point, a larger quantity of batch material is applied to the batch layer at that point.

[0007] Furthermore, existing technologies also include methods for measuring the distance between the batch layer and the feeding machine to determine the glass level in the molten glass bath and maintain it constant by adjusting the batch feed rate. For example, US 4194077 and US4302623 describe movable feeding machines for cold-top baths, each equipped with an ultrasonic sensor at its end for measuring the distance to the batch layer.

[0008] In existing technologies, the need for more in-depth data acquisition of the batch layer for operating the electrofusion bath has not yet been considered. Meanwhile, due to the increasing importance of electrofusion baths, there is a need to optimize their operation. Summary of the Invention

[0009] The task of this invention Therefore, the object of the present invention is to provide methods that can optimize the operation of an all-electric melting bath, and in particular, respond to the melting process and fluctuations therein by means of locally and temporally adjusted feed rates and optionally locally and temporally adjusted melting rates, and to provide a stable and energy-efficient glass manufacturing method.

[0010] Invention Summary This invention particularly relates to a method for collecting and analyzing data concerning the batch layer, and if necessary, the molten glass, and if necessary, the glass level, preferably in a fully electrically cooled top-mounted melting bath for molten glass, the method comprising the following steps: At least one sensor 160 is provided for non-contact acquisition of data regarding the batch layer 150. The sensor 160 is positioned at at least one end of the cantilever 120 of the feeding machine, where the batch is supplied to the glass melt. Repeatedly collect and store (a) data about the batch layer 150 collected by at least one sensor 160 during operation of the melt tank 100, wherein data is collected from at least 10 different locations, preferably at least 100 different locations, of the batch layer, and (b) assign the data to the end of the cantilever 120 or the location of the sensor 160, respectively. Process the collected data and create topography maps, optimize global topography maps, and / or optimize the best topography of batch layer 150.

[0011] Furthermore, this invention relates to using the determination method of this invention in a glass manufacturing process to control batch input. Attached Figure Description

[0012] Figure 1 A cross-section of a cold-top molten tub used to perform the method of the present invention is shown schematically.

[0013] Figure 2 A top view schematically illustrates the cantilever of a feeding machine used to perform the method of the present invention.

[0014] Figure 3 The diagram schematically illustrates the measurement of a batch layer or the morphology of a batch layer created therefrom.

[0015] Figure 4 A cross-section of a cold-top molten tub with additional microwave heating for carrying out the method of the present invention is shown schematically. Invention Details This invention relates to a method for acquiring and analyzing data regarding batch thickness and / or glass level height, particularly in an all-electrically cooled top-mounted melting bath for melting glass, and for utilizing this data to achieve an optimized melting process. In this process, data concerning spatial and temporal variations in batch thickness are identified and processed, and the morphology of the batch layer can be created.

[0016] The term "morphology" is understood here as a description or representation of the three-dimensional structure of the surface of the batch layer (see [reference]). Figure 3 The term "global morphology" is understood as the morphology of the batch layer surface that changes during the melting process. The term "optimal morphology" is understood as the morphology of a batch layer that can be determined using the method according to the invention and enables the most stable process and / or optimal glass quality for a given melting process.

[0017] Within the scope of this invention, it has been recognized that the operation of an all-electric cold-top furnace can be improved and stabilized through extensive collection and analysis of data on the batch layer and glass level. Furthermore, through extensive collection and analysis of data on the batch layer and glass level, the operation of the all-electric cold-top furnace can be monitored, and in particular, local melting rates can be determined, thereby allowing for the inference of flow conditions within the furnace.

[0018] For example, the morphology of the batch layer has been found to infer the flow inside the glass melt beneath it. This flow cannot be directly measured during the operation of the furnace, but it plays an important role in the energy efficiency of the furnace, the wear of furnace components, and the quality of the glass.

[0019] For example, the flow of hot glass can lead to varying melting rates in different areas, or the formation of gases during melting can cause "volcanoes"—gases that escape from the melt. These effects reduce the furnace's energy efficiency and affect glass flow, potentially leading to rapid short-circuit paths and consequently poor glass quality.

[0020] By understanding the morphology of the batch layer, these processes can be influenced by adjusting the batch input in both space and time to adapt to these processes. For example, the following can be achieved: In areas with high melting rates, a higher input rate can be set, while in areas with low melting rates, a lower input rate can be set.

[0021] Optional microwave heating allows for targeted setting or additional conversion of batches within the glass melt in areas with low melting rates. In areas with increased or higher melting rates, optional microwave heating can be reduced or completely disabled.

[0022] A predetermined thickness pattern (which is not uniformly thick everywhere) can be kept constant over time. For example, a hexagonal pattern consisting of thin batch layer locations with distances optimized for glass viscosity and evaporation rate can be set, and released gases can escape from the melt through these locations.

[0023] It can keep the optimal batch thickness morphology constant over time.

[0024] It has been discovered within the scope of this invention that, in addition to the spatially defined thickness of the batch layer, the temporal constancy of the defined local batch layer thickness is also crucial for a stable process.

[0025] Therefore, the method of the present invention specifies non-contact data acquisition of the entire batch layer and / or glass level and / or molten glass, particularly in a fully electrically cooled top-mounted melting furnace. The determined data is analyzed to create morphology maps, preferably global morphology maps and / or optimal morphology of the batch layer. During furnace operation, data or morphology maps are acquired at regular time intervals, and the temporal changes in morphology are analyzed to create a global morphology. Furthermore, the optimal morphology of the batch layer suitable for the corresponding melting process is determined and used to adjust the local feed rate.

[0026] A cold-top melting furnace is understood as a continuously operating glass melting furnace in which the batch is not heated from the upper structure of the furnace during its operation. This means that the batch is not heated by burners or other heating sources acting on the melt from above. However, alternatively, the batch on the melt can be locally assisted by a microwave heater (190) during melting, thereby converting it into glass melt. However, the release of microwave power does not occur "from above" (i.e., at the interface between the batch and air / gas), but rather "from below" (i.e., at the interface between the batch and the glass melt).

[0027] A schematic cross-sectional view of this cold-top molten tub 100 is shown. Figure 1 and Figure 4 In. Figure 1 In this process, the energy used for melting the batch 150 and heating the glass melt 180 is entirely introduced into the glass melt 180 through the electrode 110. Figure 4 In this process, the energy used to melt the batch 150 and heat the glass melt 180 is introduced into the glass melt 180 through the electrode 110 and the microwave heater 190.

[0028] The batch material 130 to be fed is applied to the surface of the glass melt 140 via the cantilever 120 of the feeding machine. To effectively utilize the introduced heat, the batch material applied to the surface of the glass melt 140 forms a continuous batch material blanket 150. The cantilever 120 of the feeding machine can, for example, be... Figure 2As shown, the process essentially moves to cover the entire surface of the glass melt 140 and applies the batch material 130 to be added onto the surface of the glass melt 140 or onto the existing batch material layer 150.

[0029] At least one sensor 160 is installed at at least one end of the cantilever 120 of the feeding machine for non-contact measurement of the batch layer and / or glass liquid level.

[0030] For this purpose, at least one sensor for collecting point data can be used, wherein such sensor can be selected from the group consisting of radar sensors, ultrasonic sensors, laser triangulation sensors, laser (time-of-flight) sensors, or combinations thereof. The point-by-point measurements obtained by such a sensor can be directly used to create topographic maps.

[0031] In addition, one or more point sensors can be used as an alternative, employing at least one sensor for the height of the surface being acquired. This sensor for acquiring the surface can be selected from, for example, a group consisting of a laser scanner, a 3D camera (time-of-flight, LiDAR), laser triangulation with a linear pattern, an infrared camera, a photogrammetric sensor, or a combination thereof. The acquired surface data can be used directly or by stitching together overlapping portions of the surface data to create a topographic map.

[0032] Alternatively, a combination of at least one sensor for collecting point data and at least one sensor for collecting surface data can be used, and the obtained data can be used to create a topographic map.

[0033] According to one embodiment of the present invention, one or more sensors may be encapsulated in a water-cooled and / or air-cooled housing.

[0034] Sensor data can be collected during batch feeding. Alternatively or additionally, the cantilever 120 can also move to cover the surface of the glass melt 180 without batch feeding, so that measurement data can be recorded only by, for example, a sensor 160 mounted at the end of the cantilever 120.

[0035] The obtained measurement data is processed together with the corresponding positions of the cantilever 120, and preferably the morphology of the batch layer is created (see...). Figure 3 The morphology is determined at regular intervals, and variations in the morphology are used to determine the optimal batch layer morphology. During operation, each determined morphology is compared to the specified optimal batch layer morphology, and the optimal batch feed rate for each location is determined and applied. Furthermore, deviations from the development of the batch layer morphology can be used to detect problems in the molten pool process control early.

[0036] According to one embodiment of the invention, at least one microwave heater can be provided. This at least one microwave heater can generate energy in the form of microwave radiation, wherein the generated microwave radiation at least covers the transition portion between the batch and the rough melt. The rough melt is a technical term in glass technology, referring to the melt before clarification. It is the first molten liquid phase in which all raw materials have been transformed into a liquid state but still contain bubbles.

[0037] Microwave radiation is coupled to the upper region directly beneath the batch layer, i.e., the melting reaction zone, where the temperature is increased and melting is accelerated, especially compared to other similar methods that do not use microwave radiation. Its advantage lies in the ability to locally and specifically thin the batch layer, particularly in colder areas where melting is slower, or in areas where more batch material has been applied.

[0038] Preferably, at least one microwave heater is mounted on at least one end of the cantilever 120 of the feeding machine, at which the batch is applied to the glass melt. Thus, the at least one microwave heater can move across the entire surface of the batch layer, allowing for efficient and targeted radiation of localized areas.

[0039] According to a preferred embodiment, the microwave heater generates microwave radiation with a frequency higher than 500 MHz and lower than 6 GHz, particularly lower than 3 GHz, preferably lower than or equal to 2.45 GHz or lower than or equal to 915 MHz. Microwave heating and melting of batches by microwave radiation are known to those skilled in the art, for example from WO2021 / 175506 A1.

[0040] Furthermore, the present invention relates to using the determination method according to the present invention in a glass manufacturing process to control batch input.

[0041] Furthermore, the present invention relates to using the determination method according to the present invention in a glass manufacturing process to control at least one microwave heater.

[0042] This avoids localized variations in melting rates and the formation of "volcanoes" caused by the flow of hot glass and the formation of gases during the melting process, and improves the energy efficiency of the furnace.

[0043] By controlling the local thickness of the batch layer, the glass flow can be affected and short-circuit paths in the glass melt can be avoided, thereby improving the glass quality.

[0044] Furthermore, the data acquired and processed using the method of this invention, combined with artificial intelligence, can also be used, for example, to detect anomalies during the melting process. This allows for the identification of unusual and therefore potentially dangerous conditions in the glass melt, and early warnings can be issued before critical process events occur.

[0045] List of reference numerals 100 Cold-top molten tub 110 electrode 120 batch feeding machine Batch material on the conveyor belt of the 130 batch feeding machine 140 Glass melt surface 150 batches of material layer 160 sensors 170 Exports 180 glass melt 190 Microwave heater.

Claims

1. A method for collecting and analyzing data, preferably in a fully electrically cooled top-mounted melting bath for melting glass, regarding the batch layer and, if necessary, the molten glass and, if necessary, the glass level, characterized in that, The method includes the following steps: - Provide at least one sensor (160) for non-contact acquisition of data about the batch layer (150), the sensor (160) being disposed at at least one end of the cantilever (120) of the feeding machine, at which the batch is supplied to the glass melt. - Repeatedly collect and store (a) data about the batch layer (150) collected by at least one sensor (160) during operation of the molten pool (100), wherein data is collected from at least 10 different locations, preferably at least 100 different locations, of the batch layer, and (b) assign the data to the end of the cantilever (120) or the location of the sensor (160), respectively. - Process the collected data and create topography maps, optimize global topography maps and / or optimize the best topography of batch layers (150).

2. The method according to claim 1, wherein, Point data is acquired using at least one sensor (160), wherein the sensor (160) is selected from radar, ultrasonic, laser triangulation, laser (time-of-flight, LIDAR) or a combination thereof, and / or the acquired point measurements are used directly to create the topography map. or Surface data is acquired using a sensor (160), and the sensor 160 is selected from a laser scanner, a 3D camera (time-of-flight, LIDAR), laser triangulation with line patterns, an infrared camera, photogrammetry, or a combination thereof, and / or wherein the acquired surface data is used directly to create the topographic map, or is used to create the topographic map by combining overlapping partial surface data.

3. The method according to any one of the preceding claims, wherein, At least one sensor is used to collect point data and a sensor is used to collect surface data, and the data is used to create the topographic map.

4. The method according to any one of the preceding claims, wherein, The data is collected during the batch material input process, and / or when no batch material input is being carried out simultaneously.

5. The method according to any one of the preceding claims, wherein, It also collects and processes data on glass level and / or data on glass melt.

6. The method according to any one of the preceding claims, wherein, One or more sensors are encapsulated in a water-cooled and / or air-cooled housing.

7. The method according to any one of the preceding claims, wherein, Provide at least one microwave heater, Preferably, The at least one microwave heater is installed at at least one end of the cantilever (120) of the feeding machine, at which batches are supplied to the glass melt.

8. Use of the determination method according to any one of claims 1 to 7 in a glass manufacturing method for controlling batch input.

9. Use of the determination method according to any one of claims 1 to 7 in a glass manufacturing method for controlling at least one microwave heater.

10. The use according to claim 8, characterized in that, Set smaller and / or larger batch thicknesses locally.

11. The use according to claim 8, 9, or 10, wherein, Set the optimal morphology of the batch layer determined by the method according to any one of claims 1 to 7.

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