Mixed glass production melting furnace with energy flexibility and method for producing glass

Abstract

The invention relates to a mixing furnace (10) for producing glass, in particular for supplying a floating unit, the mixing furnace (10) having a longitudinal axis (A-A '), the mixing furnace comprising:-at least one electric melting zone (110) comprising an electrode (115) adapted to be supplied with a vitrifiable mixture by means of a first feeding device (610); -a flame melting zone (120) comprising at least an overhead burner (125) adapted to be supplied with a vitrifiable mixture by a second charging device (620) separate from the at least one first charging device (610), in which the at least one electromelting zone (110) and the flame melting zone (120) arranged in series are configured to be operable independently of one another, the melting zone (110, 120) is arranged to permit selective use of either or both of the melting zones (110, 120) to impart energy flexibility to the melting furnace (10).

Description

[0001] Technical Field of the Invention

[0002] The present invention relates to a hybrid melting furnace for producing glass, in particular a hybrid melting furnace with energy flexibility, and to a method for producing glass implemented in such a hybrid melting furnace.

[0003] The present invention more specifically relates to a hybrid melting furnace for producing glass, which includes at least one electric melting zone and one flame melting zone, wherein the electric melting zone and the flame melting zone are independent of each other and can be selectively used in combination or not, thereby providing energy flexibility by allowing selection of at least one energy source such as electricity and / or fuel to melt a vitrifiable mixture to obtain molten glass, which then flows into a clarification zone having two convection circuits to obtain a suitable amount of high-quality glass.

[0004] In fact, the hybrid melting furnace according to the present invention can not only provide energy flexibility, but also deliver high-quality glass with less than 0.1 bubbles / liter at a pulling capacity of at least 400 tons / day, preferably 600-900 tons / day, or even 1,000 tons / day or more, especially providing a glass floating unit on a molten metal bath to manufacture flat glass.

[0005] The invention also relates to a method for producing glass implemented in such a hybrid melting furnace, the method comprising at least one step of melting the vitrifiable mixture in at least one electric melting zone and / or flame melting zone of the hybrid melting furnace. Prior art

[0006] Different exemplary designs of melting furnaces for producing glass, depending inter alia on the product to be produced, that is to say the final shape of the glass, are known from the prior art.

[0007] Therefore, different furnace designs are differentiated depending on whether the planned production involves fiberglass, industrial insulating glass forming or flat glass.

[0008] An industrial challenge in glass melting furnace design is to be able to obtain glass with quality requirements depending on the product. Flat glass production is relatively the most demanding in this regard.

[0009] Due to its versatility, flat glass is produced in large quantities for a wide range of applications. It is widely used in the electronics (flat screens), architectural and automotive sectors, where it can be processed using a wide variety of techniques (bending, tempering, etc.), making it a base glass for a full range of glass products.

[0010] In view of the quality and quantity problems involved, the invention is particularly directed to the manufacture of such flat glass for industrial shaping, which is usually obtained by means of a glass floating unit on a bath of molten metal, usually tin, which is why this flat glass is still called float glass.

[0011] For the manufacture of flat glass, it is desirable to be able to supply the float unit with high quality glass, ie glass containing as few bubbles as possible, ie typically glass having less than 0.5 bubbles / litre.

[0012] The quality of the glass is determined in particular, but not exclusively, by the number of bubbles present in the glass, expressed as "bubbles per litre". The lower the number of bubbles per litre in the glass, the higher its quality is considered to be.

[0013] It should also be remembered that the presence of bubbles (or gaseous defects) in the glass is inherent to the glass manufacturing process, in which there are generally three consecutive stages or steps: melting, fining and homogenization, and thermal conditioning of the glass.

[0014] The presence of bubbles in the glass leads to a melting step, during which the vitrifiable mixture, also called the "composition", is melted. The presence of bubbles in the glass is due to a melting stage, during which the vitrifiable mixture, also called the "composition", is melted. The vitrifiable mixture consists of raw materials including, for example, a mixture of sand, limestone (calcium carbonate), soda ash and dolomite used in the manufacture of soda-lime glass (the glass most commonly used in flat glass manufacturing), to which cullet is advantageously added, the cullet consisting of crushed glass to facilitate melting.

[0015] The vitrifiable mixture is converted into a liquid substance in which even the most immiscible particles (ie, those richest in silicon dioxide or silicon dioxide (SiO2) and poorest in sodium oxide (Na2O)) dissolve.

[0016] Sodium carbonate (Na2CO3) begins to react with the sand particles at 775°C, releasing bubbles of carbon dioxide (CO2) into the liquid, which becomes increasingly viscous as the carbonates convert to silicates. Similarly, the conversion of limestone particles into lime and the decomposition of dolomite also result in the emission of carbon dioxide (CO2).

[0017] The melting stage is complete when there are no more solid particles in the molten glass, which has become highly viscous and, at this stage of the manufacturing process, is full of air and gas bubbles.

[0018] Then, the fining and homogenization steps make it possible to eliminate the bubbles present in the molten glass. As is known, in this stage it is advantageous to use a "fining agent", i.e. a substance in low concentration which decomposes at the melting temperature of the molten bath, providing gas to expand the bubbles, thus accelerating their rise to the surface of the glass.

[0019] The thermal conditioning phase of the manufacturing process then makes it possible to reduce the temperature of the glass, since at the beginning of the forming operation the viscosity of the glass must generally be at least ten times greater than during fining.

[0020] Each of the steps in making glass just described corresponds naturally to the structure of the furnace used to carry out those steps.

[0021] Typically, this type of glass melting furnace includes a melting zone where the glass batch is melted to form a glass molten pool, followed by a fining and homogenizing zone to eliminate glass bubbles, and finally a heat conditioning zone to cool the glass to its forming temperature, which is much lower than the temperature the glass experiences during its production.

[0022] From the above-mentioned glass manufacturing process, we can see that the melting stage is accompanied by the emission of carbon dioxide (CO2), which is one of the main greenhouse gases involved in climate change.

[0023] For this reason, efforts are underway to use ever-increasing proportions of cullet in order to reduce these direct CO2 emissions, as well as the indirect CO2 emissions associated with the raw materials used in the vitrifiable mixture.

[0024] Indeed, besides the industrial challenge of manufacturing high quality glass and achieving high productivity at the lowest possible furnace construction and operating costs, one of the other main current challenges that the glass industry has to face is ecological, namely the need to find solutions to reduce the carbon footprint (or CO2 footprint) of the glass production process.

[0025] To achieve carbon neutrality, it is preferable to take a global approach to the process, seeking to act in a variety of ways to reduce direct and indirect emissions during manufacturing, as well as upstream and downstream emissions in the value chain, such as those associated with the transportation of upstream materials and downstream products.

[0026] These various approaches therefore include product design and material composition, improving the energy efficiency of industrial processes, using renewable and decarbonized energy, working with feedstock suppliers and transporters to reduce their emissions, and finally exploring technologies for capturing and storing residual emissions.

[0027] In addition to the direct emissions inherent in the glassmaking process described above, the type of energy used, especially for the high temperature melting stage (over 1500°C), accounts for the largest share of the carbon footprint of the glassmaking process as it typically involves fossil fuels, most often natural gas or even petroleum products such as fuel oil.

[0028] Research into new furnace designs must therefore not only meet industrial challenges related to glass quality, but also reduce the carbon footprint of the glassmaking process, in terms of direct and indirect carbon dioxide (CO2) emissions, in particular by reducing the use of fossil fuels.

[0029] Glass is made in furnaces which have evolved from the first pot (or crucible) furnaces to the Siemens furnace (which is generally considered the predecessor of the modern large-scale continuous casting glass furnace), such as the cross-fired furnace which can produce up to 1200 tons of float glass per day.

[0030] The choice of energy for melting therefore leads to two common large furnace designs for making glass, namely the flame furnace and the electric furnace.

[0031] According to a first design, flame melting furnaces generally use fossil fuels, in particular natural gas, for the burners; thus, thermal energy is transferred to the glass by heat exchange between the flame and the surface of the glass bath.

[0032] The above-mentioned side-fired furnace is an example of a melting furnace of the first design and is widely used to feed molten glass to floating units intended for the manufacture of flat glass.

[0033] According to a second design, the electric melting furnace is one in which thermal energy is generated by the Joule effect in a molten glass mass.

[0034] In fact, glasses, being insulating substances at room temperature, become conductive at high temperatures, making it conceivable to use the Joule effect to heat them in glass melts.

[0035] However, electric melting furnaces are used, for example, for the production of special glasses, such as opal glass with fluorine or lead crystals, or generally for the manufacture of glass fibers for thermal insulation.

[0036] Indeed, it is generally accepted by those skilled in the art that such electric furnaces are incapable of providing sufficient quantity or quality (less than 0.5 bubbles / liter as a reminder) of glass to float glass units on a molten metal bath intended for making flat glass.

[0037] Prior art electric melting furnaces known to the applicant are capable of delivering at most 200 to 250 tonnes per day of glass pulls having at most a few hundred, more typically a few thousand, bubbles per litre, which may be suitable for forming hollow glass, typically bottles, but is by no means the case for making flat glass and thereby supplying floating units.

[0038] This is why flame furnaces (such as horizontal-fired furnaces) are still the only furnaces capable of supplying such float glass units.

[0039] However, flame furnaces rely on the use of fossil fuels, primarily natural gas, making their carbon footprint barely compatible with the goal of reducing carbon dioxide (CO2) emissions, i.e. the carbon footprint of the glass production process.

[0040] To complete the description of furnace designs for glassmaking according to the prior art, reference will be made to a "third design" of a furnace having recently known variations in order in particular to face the ecological problem of reducing carbon dioxide emissions (CO 2 ).

[0041] This third furnace design is based on a flame furnace but uses electrical auxiliary heating, particularly for instantly increasing the output of the furnace or improving the quality of the glass.

[0042] Therefore, this type of furnace is also called an "electrically assisted flame furnace".

[0043] A melting furnace according to this third design therefore combines several energy sources, respectively fossil fuels and electricity, and is therefore also referred to as a “hybrid” melting furnace.

[0044] The addition of electrical auxiliary heating makes it possible to increase the melting capacity of a flame melting furnace, which is limited by the heat transfer occurring between the flame and the glass bath surface.

[0045] However, the operation of such a hybrid furnace is always mainly based on the use of fossil fuels (usually gas), so that the impact finally obtained on improving the carbon footprint of the glass production process is still limited. In fact, electricity is used here only as an auxiliary tool, so that its impact is proportional.

[0046] Furthermore, in order to effectively improve the carbon footprint, the electricity used must still be so-called “green” electricity, ie electricity generated from renewable and decarbonized energy sources.

[0047] Note that the above comments about electricity apply equally to fuels such as biomethane or hydrogen, which can be used to replace natural gas in the burner.

[0048] While improving the carbon footprint of glass manufacturing methods is a key issue, controlling manufacturing costs is also a major concern, as evidenced by market players’ commitment to producing “zero carbon” glass.

[0049] Since glass production is particularly energy-intensive, in particular the melting phase of the vitrifiable mixture, the choice of the energy used in the glass production furnace is a decisive factor both economically and ecologically.

[0050] In general, energy costs follow market laws and vary according to supply and demand, but it should be noted that depending on the type of energy used directly or converted into electricity (natural gas, oil, etc.), resources are unevenly distributed on the earth, making geopolitical issues such as war particularly likely to have a great impact on them.

[0051] When it comes to designing a new furnace for making glass, energy choices are of utmost importance and are met with many uncertainties, not least the economic risks associated with energy costs and even whether it will be available in sufficient quantities to meet the ecological challenges of “zero carbon” glassmaking.

[0052] The invention also aims to propose a new furnace design for producing glass that limits the economic risks associated with the choice of energy, while being able to provide high quality glass on the one hand and the required quantity on the other hand, particularly suitable for supplying float glass units intended to produce flat glass, and making it possible to achieve a reduction in carbon dioxide (CO2) emissions associated with the glass manufacturing process. Summary of the invention

[0053] To this end, the invention proposes a hybrid glassmaking furnace, in particular for supplying a unit for floating glass on a bath of molten metal, said hybrid furnace having a longitudinal axis, said hybrid furnace comprising:

[0054] at least one electric melting zone adapted to be supplied with a vitrifiable mixture by at least one first feeding device and comprising electrodes for melting said vitrifiable mixture;

[0055] a flame melting zone, which is separate from the at least one electric melting zone, adapted to be supplied with a vitrifiable mixture by means of at least one second feeding device and which comprises at least one overhead burner for melting the vitrifiable mixture, said overhead burner being arranged above the surface of the molten glass,

[0056] wherein the at least one electric melting zone and the flame melting zone are arranged in series so that molten glass produced by one of the upstream melting zones can flow into the other of the downstream melting zones, and wherein the at least one electric melting zone and the flame melting zone are configured to operate independently of each other so as to allow selective use of either or both of the melting zones to provide energy flexibility for the melting furnace,

[0057] a fining zone for molten glass delivered by said at least one electric melting zone and / or said flame melting zone, said fining zone being configured to include a first convection circuit and a second convection circuit; and

[0058] A zone for cooling the glass, comprising a conditioning tank, which is penetrated by a second convection circuit and is connected to at least one glass flow channel.

[0059] Advantageously, the hybrid melting furnace according to the invention is characterized in that it comprises at least two melting zones which are separate and independent from each other and can be selectively operated using different energy sources.

[0060] Advantageously, the hybrid melting furnace comprises at least a first melting zone using a first energy and a second melting zone using a second energy different from the first energy, whereby the first energy and / or the second energy can be selectively used, which is particularly beneficial to the energy flexibility of glass manufacturing.

[0061] Preferably, the first energy is electricity and the second energy is fuel.

[0062] Advantageously, the design of the hybrid melting furnace according to the invention allows total energy flexibility and is able to use only one of the at least one electric melting zone and the flame melting zone of the melting furnace, or both in configurable proportions, to melt the vitrifiable mixture.

[0063] Thus, the hybrid furnace provides several operating modes in terms of the selection of energy for melting the vitrifiable mixture, ie more generally a multi-mode operation, wherein the selected operating mode of the hybrid furnace is determined based on at least one selection parameter comprising one or more criteria.

[0064] For each glass production method, it may be desirable to give priority to at least one criterion at any given moment, or even to seek an optimal compromise according to several criteria, such as economic, ecological or even technical criteria.

[0065] The economic criterion of energy cost is only one of the criteria that may be taken into account when making the selection, such as the ecological criterion of the carbon footprint (CO2) of the energy used, and even one or more technical criteria.

[0066] When the electric melting zone and the flame melting zone are used together, there is again flexibility, since the proportion of molten glass that can be produced by each of them can be freely parameterized, in particular by acting on the associated feeding devices and heating devices for melting, i.e. electrodes and overhead burners.

[0067] Thus, the electricity used to power the electrodes and the fuel used to power the overhead burners may be the same or different, for example in a 50 / 50 ratio (i.e., 50% each). The electricity may also predominate over the fuel (or vice versa), for example with an 80 / 20 ratio (i.e., 80% electricity and 20% fuel) or any other ratio, such as 70 / 30 or 60 / 40.

[0068] In this operating mode, called hybrid, a charging device is associated with each of the electric melting zone and the flame melting zone, respectively, and then supplies them with vitrifiable mixture proportionally and selectively, and in this case also participates in obtaining the energy flexibility of the hybrid melting furnace according to the invention.

[0069] In the hybrid melting furnace according to the present invention, the maximum pull capacity of at least one electric melting zone and the maximum pull capacity of the flame melting zone are determined by design, and each can be sized to deliver a pull capacity equal to the desired nominal pull capacity of the melting furnace, so that this nominal pull capacity can be achieved even when only one of the melting zones is used, that is, a single energy source for melting, electricity or fuel.

[0070] However, it is also possible to dimension at least one of the furnace melting zones so that its maximum draw is less than the nominal draw of the furnace, thereby benefiting from a reduction in the size of the at least one melting zone. In this case, the nominal draw of the furnace can be achieved only by using the electric and flame melting zones together, or by using another melting zone if the other melting zone is dimensioned to deliver a maximum draw equal to the nominal draw of the furnace.

[0071] Due to the design of the hybrid furnace according to the invention, this multi-mode operation ensuring energy flexibility is provided, which can significantly reduce the risks associated with the selection of a given energy, the cost and availability of which may vary greatly on the market during the entire operating life of the furnace, in particular based on the supply / demand ratio.

[0072] In contrast to the present invention, it is understood that in melting furnaces according to the prior art, in which the melting of the vitrifiable mixture is achieved with a single energy source, usually fuel in a first design or electricity in a second design, there is no energy flexibility.

[0073] In case the energy costs for melting increase significantly or it is not available, the consequences can even jeopardize the glass production, leading to furnace shutdowns.

[0074] This also applies to the hybrid furnace according to the third design, even if fuel and electricity (as a booster) are used, since in such a furnace the molten glass production cannot be achieved with a single energy source, in particular with electricity alone.

[0075] In general, it should be remembered that building a furnace for glass production is a very expensive investment and takes a long time to amortize the costs of operating such a furnace, usually in excess of twenty years, which also necessarily influences the choices made when building a furnace.

[0076] However, the energy flexibility offered by the hybrid furnace according to the invention is only one of the advantages, since the design of the furnace also makes it possible to obtain very high quality glass in the quantities required to supply float glass units for making flat glass, which is by far the most demanding application.

[0077] The serial arrangement of the at least one electric melting zone and the flame melting zone relative to one another advantageously facilitates mixing of the molten glass delivered by each zone when the zones are used together in a hybrid mode of operation.

[0078] Due to the serial arrangement of the at least one electric melting zone and the flame melting zone, molten glass produced by one of the upstream melting zones can flow into another of the downstream melting zones, thereby promoting glass mixing, particularly due to the temperature of the glass present in each of the melting zones.

[0079] In addition to the series arrangement, the two glass convection loops also contribute to obtaining very high quality glass with less than 0.1 bubbles per liter, especially the first convection loop extending into the flame melting zone and the fining zone.

[0080] Advantageously, the hybrid melting furnace comprises a neck interconnecting said at least one electric melting zone and said flame melting zone.

[0081] In the hybrid melting furnace according to the invention, since the non-return glass separation device is advantageously arranged in the neck, no convection loop or glass recirculation loop extends from the flame melting zone to the electric melting zone, whether the electric melting zone is used or not.

[0082] Comparatively, the submerged flow hole connecting the electric melting zone to the flame melting zone will not ensure this function of preventing glass from returning to the melting furnace. In fact, the return flow of glass must exist in the flow hole, especially due to the wear of the material.

[0083] Furthermore, the glass flowing in the flow tunnel has no contact with the atmosphere, so that it also cannot be cooled on the surface in a controlled and variable manner, in particular by means of cooling devices, such as air circulation cooling devices.

[0084] Unlike flow holes in which bubbles are trapped in the glass, the choke advantageously enables bubbles present in the glass to be discharged to the surface. In addition, contact between the bubbles and the refractory in the flow hole results in accelerated corrosion at the interface, leading to premature wear of the flow hole and "chemical contamination" of the glass by the material forming the refractory.

[0085] The choke also allows the glass to flow in a draw volume capable of supplying the floating unit, compared to a flow hole whose cross section is restricted by the structure.

[0086] Compared to a flow hole, the glass leaving the neck has a higher temperature because it is located near the surface of the melt pool in the upstream melting zone from which it came, as opposed to the glass at the bottom. However, since the glass enters from the top, the neck can be used to cool the glass.

[0087] This cooling of the glass can be passive (mainly by radiation) or active (by means of cooling means), thereby controlling the temperature of the glass flowing into the neck, in particular in order to obtain an optimal mixing with the glass present in the melting zone located downstream of the neck. Cooling the glass obtained in the neck (with or without cooling means) is also particularly advantageous when the glass is produced by electromelting, since the molten glass generally has a high temperature (compared to the temperature of flame melting), which may need to be reduced.

[0088] Further advantageous features of the invention are in particular the subject matter of the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Other features and advantages of the present invention will become apparent upon reading the following detailed description, for understanding of which reference is made to the accompanying drawings, wherein:

[0090] - Figure 1 is a cross-sectional view through a vertical plane along the longitudinal axis A-A' of the melting furnace, showing a hybrid melting furnace for producing glass according to a first embodiment of the invention, the hybrid melting furnace comprising independent electric melting zones and flame melting zones, and showing said electric melting zone connected to the flame melting zone by a neck, said flame melting zone being connected to a fining zone, said fining zone comprising a first convection circuit and a second convection circuit, said second convection circuit itself being subsequently connected to a cooling zone crossed by said second convection circuit;

[0091] - Figure 2 is a horizontal cross-sectional view showing a melting furnace according to a first embodiment as seen from above, and also showing a first charging device for feeding the electric melting zone and a second charging device for feeding the flame melting zone, these melting zones being connected to each other by a neck including a “non-return” separation device configured to prevent molten glass from flowing back from the flame melting zone to the electric melting zone;

[0092] - Figure 3 It is detailed according to Figure 1 A cross-sectional view of the neck of a mixing furnace, and showing a preferred example of the "non-return" separation device of the glass formed by the protrusion at the bottom of the neck;

[0093] - Figure 4 is with Figure 3A similar cross-sectional view showing in detail the neck of the mixing furnace and showing another example of the design of the "non-return" separation device for glass, comprising a movable baffle and a protrusion at the bottom of the neck;

[0094] - Figure 5 is similar to Figure 2 sectional view showing the melting furnace in a first electromelting operating mode according to a first embodiment and also showing an electromelting zone covered with a layer of a vitrifiable mixture held downstream by a fixture, the melting of the layer of vitrifiable mixture to obtain molten glass being performed exclusively in said zone using electricity as energy source;

[0095] - Figure 6 is similar to Figure 2 sectional view showing a melting furnace in a second hybrid operating mode according to the first embodiment, wherein the melting of the vitrifiable mixture is carried out jointly in an electric melting zone and a flame melting zone, each supplied by a separate feeding device, and showing the electric melting zone covered by a layer of the vitrifiable mixture introduced by the first feeding device and the flame melting zone covered by a layer of the vitrifiable mixture introduced by the second feeding device comprising two intermittent feeders;

[0096] - Figure 7 is similar to Figure 2 sectional view showing the melting furnace according to the first embodiment in a third flame melting operating mode and also showing a flame melting zone covered with a layer of a vitrifiable mixture, the melting of the vitrifiable mixture being performed by combustion in said zone provided with a burner powered by fuel to obtain molten glass;

[0097] - Figure 8 is a cross-sectional view through a vertical plane along the longitudinal axis A-A' of the melting furnace, showing a hybrid melting furnace for producing glass according to a second embodiment of the present invention, the hybrid melting furnace comprising two electric melting zones and one flame melting zone, and showing the flame melting zones connected to the first and second electric melting zones arranged transversely, respectively, the flame melting zones being connected to a clarification zone comprising a first convection circuit and a second convection circuit, the clarification zone itself being connected to a cooling zone through which the second convection circuit passes;

[0098] - Fig. 9 is a horizontal sectional view of a hybrid melting furnace according to a second embodiment as seen from above, further showing a first electric melting region and a second electric melting region arranged laterally on both sides of a flame melting region, each of said regions being connected to the flame melting region by a neck;

[0099] - Fig.10 is along Fig. 9 , which shows a hybrid melting furnace according to a second embodiment and shows a first electric melting zone and a second electric melting zone connected transversely to the flame melting zone by a first and a second neck, respectively, each neck comprising a "non-return" separation device for the glass, similar to Figure 3 "non-return" separation device;

[0100] - Fig.11 is similar to Fig. 9 sectional view showing a melting furnace in a first electric melting operation mode according to a second embodiment, and also showing a first electric melting zone and a second electric melting zone respectively covered with a layer of a vitrifiable mixture held by a fixture, the melting of the layer of vitrifiable mixture to obtain molten glass being carried out only in said zones with electricity as an energy source, without using a flame melting zone;

[0101] - Fig.12 is similar to Fig. 9 , showing a melting furnace in a second hybrid operation mode according to a second embodiment, wherein melting of the vitrifiable mixture is performed jointly in first and second electric melting zones and in a flame melting zone, and showing two electric melting zones covered with layers of the vitrifiable mixture introduced by first and second intermittent feeders of a first feeding device, respectively, and a flame melting zone into which the vitrifiable mixture is introduced by a second feeding device separate from the first feeding device.

[0102] Detailed description of the drawings

[0103] In the remainder of the description, the longitudinal, vertical and transverse orientations will be used without limiting reference to the axis system (L, V, T) shown in the drawings.

[0104] When referring to the longitudinal direction, the terms "upstream" and "downstream" will also be used without restriction, and when referring to the vertical direction, the terms "up" and "downstream" or "top" and "bottom" will also be used without restriction, and when referring to the lateral direction, the terms "left" and "right" will finally be used without restriction.

[0105] In this specification, the terms "upstream" and "downstream" correspond to the flow direction of the glass in the melting furnace, and the glass flows from upstream to downstream along the longitudinal axis A-A' (upstream from A, downstream from A') of the mixing melting furnace, such as Figure 2 and 9 Specifically shown in.

[0106] Furthermore, the term "loop" is used herein in conjunction with the recycling of glass in a furnace as is well known to those skilled in the art, as is the concept of "cold top" and "hot top" for glassmaking furnaces.

[0107] The drawings showing the hybrid melting furnace according to the invention are not true to scale.

[0108] Figure 1 and 2 Cross-sectional views illustrating a mixing melting furnace 10 for producing glass according to a first embodiment of the present invention from the side and the top are shown, respectively.

[0109] Similar to the third melting furnace design described above, the term "hybrid" is used here to define the melting furnace according to the invention, in particular because it is possible to use two different energy sources, in particular when the operating mode of the melting furnace is a so-called hybrid mode, in which the melting of the vitrifiable mixture is obtained using both electrical energy and fuel energy.

[0110] However, the analogy with the present invention does not go beyond this scope, since it is possible that only one of the electrical energy (constituting the first energy source) and the fuel energy (constituting the second energy source) is used to achieve melting, in particular in other operating modes of the melting furnace, so that when used, the electrical energy never constitutes an auxiliary in the hybrid melting furnace 10 according to the present invention.

[0111] The hybrid melting furnace 10 according to the invention is particularly intended for supplying a float glass unit on a bath of molten metal, typically tin, for the manufacture of flat glass.

[0112] like Figure 1 and 2 As shown, the hybrid melting furnace 10 according to the first embodiment includes a melting zone 100, a clarification and homogenization zone 200 (hereinafter referred to as the clarification zone 200) and a glass cooling zone 300 in sequence from upstream to downstream along the longitudinal axis AA' of the melting furnace.

[0113] Preferably, the hybrid melting furnace 10 is symmetrical in design with respect to the longitudinal axis AA′.

[0114] In the hybrid melting furnace 10 according to the present invention, the melting zone 100 includes at least one melting zone 110 using a first energy such as electrical energy, and a melting zone 120 using a second energy such as fuel energy (ie, a second energy different from the first energy).

[0115] In the remainder of the description, the at least one melting zone 110 corresponds to an “electric” melting zone, and the melting zone 120 corresponds to a “flame” melting zone, due to the use of at least one fuel.

[0116] In the hybrid melting furnace 10 according to the present invention, the at least one electric melting zone 110 and the flame melting zone 120 which together form the melting zone 100 of the melting furnace are structurally separated, that is, they constitute separate melting zones and are functionally independent of each other.

[0117] The at least one electromelting zone 110 is capable of delivering a maximum draw less than or equal to the nominal draw of the furnace, ie between 0% and 100%, preferably up to 100%, of the nominal draw, so that the nominal draw can be obtained by electromelting alone.

[0118] The flame melting zone 120 is capable of delivering a maximum draw less than or equal to the nominal draw of the furnace, i.e., between 0-100% of the nominal draw, preferably up to 100% so that the nominal draw can be obtained only by flame melting, or even between 0-50% of the nominal draw.

[0119] When the flame melting zone 120 is capable of delivering a maximum pull amount between 0% and 50% of the nominal pull amount, the nominal pull amount can only be obtained by using flame melting and electric melting together, or if the at least one electric melting zone 110 is capable of delivering a maximum pull amount corresponding to 100% of the nominal pull amount, it can be obtained by only the at least one electric melting zone 110.

[0120] Preferably, and in contrast to the at least one electric melting zone 110 , the hybrid melting furnace 10 according to the present invention comprises a single flame melting zone 120 .

[0121] According to the present invention, the at least one electric melting zone 110 and the flame melting zone 120 are configured to be able to operate independently of each other so as to allow selective use of one and / or the other of the melting zones 110 and 120 and thereby impart energy flexibility to the hybrid melting furnace 10.

[0122] Due to this design, the hybrid melting furnace 10 can be operated in several modes, depending on whether only one or two energy sources, electricity and / or fuel, are used simultaneously to melt the vitrifiable mixture.

[0123] Will refer to later Figures 5 to 7 The mode of operation of the hybrid melting furnace 10 is described in more detail.

[0124] The hybrid melting furnace 10 according to the invention is in fact capable of operating in an operating mode that can be selected from the following:

[0125] a first electromelting operation mode, in which molten glass is produced only by the at least one electromelting zone 110;

[0126] - a second hybrid operation mode, in which molten glass is produced by both the at least one electric melting zone 110 and the flame melting zone 120;

[0127] A third flame-melting operating mode, in which molten glass is produced only by the at least one flame-melting zone 120 .

[0128] Advantageously, the hybrid melting furnace 10 is also characterized by its multi-mode operation, enabling one or more energies for melting the vitrifiable mixture to be selected according to the selected operating mode, thereby giving the hybrid melting furnace 10 according to the present invention energy flexibility.

[0129] We will first describe the melting zone 100 of the hybrid melting furnace 10 according to the first embodiment, and then the fining zone 200 and the glass cooling zone 300 .

[0130] The hybrid melting furnace 10 comprises, on the one hand, at least one electric melting zone 110 , which can be supplied with a vitrifiable mixture via at least one first charging device 610 , and, on the other hand, a flame melting zone 120 , which can be supplied with a vitrifiable mixture via at least one second charging device 620 .

[0131] The second charging device 620 associated with the flame melting zone 120 is separate and operationally independent from the first charging device 610 associated with the at least one electric melting zone 110, so that one and / or the other charging device can be selectively used depending on the selected furnace operating mode.

[0132] exist Figures 1 to 7 In the illustrated first embodiment of the present invention, the hybrid melting furnace 10 includes a single cold top electric melting zone 110 and a hot top flame melting zone 120 .

[0133] Preferably, the hybrid melting furnace 10 includes a first feeding device 610 composed of a single intermittent feeder for feeding the vitrifiable mixture to the electric melting area 110. Figure 2 It is schematically indicated by arrows.

[0134] Preferably, the intermittent feeder forming the first feeding device 610 is arranged longitudinally upstream of the electric melting area 110, such as Figure 2 shown.

[0135] Optionally, the first feeding device 610 includes more than one intermittent feeders, for example, two intermittent feeders, to feed materials to the electric melting area 110 (which is a cold top type).

[0136] Optionally, the first charging device 610 is arranged not longitudinally but transversely to the furnace axis (A-A'), in particular when the first charging device 610 comprises more than one batch feeder.

[0137] Advantageously, first feeding device 610 is configured to spread the vitrifiable mixture into a layer covering the entire surface of the molten glass in electromelting zone 110, preferably substantially uniformly.

[0138] Reference may be made, for example, to FR 2 599 734, which describes a feeding device or intermittent feeder suitable for spreading the vitrifiable mixture in the form of such a layer to cover the surface of a bath of molten glass.

[0139] Preferably, the second feeding device 620 for supplying the vitrifiable mixture to the flame melting zone 120 includes a first intermittent feeder 622 and a second intermittent feeder 624, which are arranged laterally on both sides of the flame melting zone 120, preferably perpendicular to the longitudinal axis (A-A') of the melting furnace.

[0140] Alternatively, the second feeding device 620 includes a single batch feeder for supplying the vitrifiable mixture to the flame melting zone 120 .

[0141] The first intermittent feeder 622 and the second intermittent feeder 624 are each Figure 2 It is schematically indicated by arrows.

[0142] The prior art includes a number of examples of screw batch feeders, particularly but not exclusively suitable for supplying a vitrifiable mixture to such a flame melting zone 120 of a hybrid melting furnace 10 according to the present invention.

[0143] The vitrifiable mixture (also sometimes referred to as a "composition") generally consists of raw materials and broken glass (or "cullet"), which are melted to produce a molten glass.

[0144] In a known manner, cullet consists of glass fragments which are obtained by recycling glass and which are ground and usually cleaned before being subsequently added to the raw materials for producing glass again.

[0145] Advantageously, cullet promotes melting, that is, transformation by melting of the vitrifiable glass mixture. Since cullet has a lower melting point than sand, the use of cullet further saves sand and thus energy, helping to reduce the carbon footprint of the production process.

[0146] Furthermore, cullet makes it possible to upcycle used glass by recycling it (glass is infinitely recyclable), thereby reducing the amount of raw materials required to manufacture glass and in turn helping to reduce the carbon footprint of the glass manufacturing process.

[0147] Advantageously, the vitrifiable mixture contains 10 to 40% of cullet, preferably 30 to 70%, or even 100% of cullet.

[0148] Preferably, the vitrifiable mixture introduced into the melting furnace by the first feeding device 610 associated with the at least one electric melting zone 110 and the vitrifiable mixture introduced into the melting furnace by the second feeding device 620 associated with the flame melting zone 120 have similar compositions. This is especially true when the electric melting zone 110 and the flame melting zone 120 are used together in a second so-called hybrid operating mode.

[0149] A “similar” composition of the vitrifiable mixture is understood to mean a chemical composition that is essentially identical to the chemical composition of the glass to be produced.

[0150] However, the vitrifiable mixtures introduced into the electric melting zone 110 and the flame melting zone 120, respectively, do not have to be the same; in particular, the amount of cullet in each vitrifiable mixture may be different, or even a fining agent may be selectively added to one vitrifiable mixture and not to the other.

[0151] Advantageously, the at least one electric melting zone 110 and the flame melting zone 120 are arranged in series so that molten glass produced by one of the upstream melting zones can flow into the other of the downstream melting zones.

[0152] Due to this arrangement, when the electric melting zones and flame melting zones are used together, molten glass produced by one of the melting zones mixes with molten glass produced by the other of the melting zones, such as in a second mixing operating mode of the melting furnace.

[0153] In this first embodiment, the hybrid melting furnace 10 includes, for example, a charging zone 111 in the longitudinal direction, in which a first charging device 610 (also called an intermittent feeder) is arranged, which is intended to be used to introduce a vitrifiable mixture into the electric melting zone 110. Figure 1 and 2 It is schematically shown by arrows.

[0154] Advantageously, the feeding device 610 is configured to deposit the vitrifiable mixture so as to form a layer 112 over the entire surface of the molten glass pool 113, such as Figure 5 and 6 In particular, it is shown that a layer 112 of a vitrifiable mixture has been formed over the entire surface of a molten glass pool 113 .

[0155] The layer 112 of vitrifiable mixture forms an insulating layer between the glass bath 113 and the top 114 of the electromelting region 110, which is why such electromelting region 110 is referred to as a "cold top".

[0156] Preferably, the glass bath 113 is uniformly covered with a layer 112 of vitrifiable mixture, for example 10 to 40 cm thick, and beneath which complex chemical reactions take place, as described in the preamble of the present application, which result in molten glass being obtained.

[0157] The electric melting region 110 includes an electrode 115 configured to melt the vitrifiable mixture introduced by the first feeding device 610 to obtain a molten glass, in particular Figure 1 The molten glass pool 113 is shown in FIG.

[0158] In the electrofusion zone 110 , the power dissipated around the electrode 115 generates a zone of high convection comprising in particular very strong upwellings which provide the necessary calories at the boundary between the cast iron and the vitrifiable mixture forming said layer 112 .

[0159] Furthermore, although permeable to carbon dioxide (CO 2 ), the layer 112 of vitrifiable mixture present on the surface of the molten pool 113 advantageously makes it possible to capture, by condensation or by chemical reaction, the vapors evolved by the molten glass, which vapors are sometimes toxic, depending on the composition.

[0160] Advantageously, the electrode 115 is arranged on the surface so as to be immersed in the glass bath 113 through the layer 112 covering the surface of the bath 113, such as Figure 1 shown.

[0161] Preferably, the immersed electrode 115 extends vertically. Alternatively, the immersed electrode 115 extends obliquely, that is, is inclined at a predetermined angle relative to the vertical direction.

[0162] Alternatively, the electrode 115 is arranged to pass through the bottom 116 of the electro-melting zone 110 so as to be completely immersed in the molten pool 113, and the rising electrode (as opposed to the immersed electrode) preferably extends vertically or obliquely.

[0163] The submerged electrodes 115 also allow their wear state to be more easily controlled compared to electrodes arranged through the bottom and result in the dissipation of electrical energy from the vitrifiable mixture layer 112 advantageously closer to the molten interface.

[0164] Furthermore, compared to the raised electrode, the submerged electrode 115 can keep the bottom 116 of the electrofusion zone 110 without any openings.

[0165] Preferably, if Figure 1 As shown, the bottom 116 of the electromelting zone 110 is flat. As a variant, the bottom 116 comprises at least one depth variation relative to the surface of the molten glass pool 113, said variation comprising at least one height and / or at least one level variation.

[0166] Preferably, the molten electrodes 115 are evenly distributed in the molten pool 113. Figure 1 and Figure 2 The number of nine electrodes 115 shown in is merely an illustrative example and is thus in no way limiting.

[0167] Alternatively, the electrofusion zone 110 may cumulatively include submerged electrodes and raised electrodes.

[0168] According to another alternative arrangement, at least a portion of the electrode 115 passes through at least one side wall delimiting the electrofusion zone 110, the electrode 115 then extending horizontally and / or obliquely.

[0169] Advantageously, the 115 electrode is made of molybdenum, a refractory metal that withstands temperatures of 1700° C. and is particularly suitable for melting glass using the Joule effect, since glass becomes conductive only at high temperatures.

[0170] Advantageously, the electrofusion zone 110 includes a region of low convection, referred to as a buffer zone 117 , located between the free end of the submerged electrode 115 and the bottom 116 .

[0171] The electric melting zone 110 of the hybrid melting furnace 10 is therefore configured to have a determined depth below the submerged electrode 115 in order to obtain such a low convection buffer zone 117 .

[0172] Preferably, the depth between the free end of the immersion electrode 115 and the bottom 116 is greater than 600 mm, preferably greater than 800 mm.

[0173] Such a low convection buffer area 117 constitutes another reason to prefer an immersed electrode 115 over an elevated electrode extending through the bottom 116.

[0174] Advantageously, the presence of the low convection buffer region 117 directly contributes to obtaining high quality glass by promoting a longer residence time of the glass in the electric melting region 110 .

[0175] like Figure 1 and 2 As shown, the electric melting zone 110 is located upstream of the flame melting zone 120, and the glass flows through the mixing furnace 10 from upstream to downstream, ie, along the longitudinal axis AA' of the furnace.

[0176] Advantageously, the downstream electric melting zone 110 and the flame melting zone 120 are connected by a clamping neck 160 (i.e., Figure 2 The areas of reduced width shown) are connected to each other.

[0177] Thus, when the electric melting zones and flame melting zones are used together, the molten glass produced by the electric melting zone 110 is advantageously mixed with the molten glass produced by the flame melting zone 120, as in a second mixing operating mode of the melting furnace.

[0178] When the flame melting zone 120 is not used, as in the first electric melting mode, the molten glass produced by the electric melting zone 110 flows through the flame melting zone 120 to the downstream fining zone 200 .

[0179] Advantageously, such a neck 160 ensures cooling of the molten glass as it flows from the electric melting region 110 to the flame melting region 120; the longer the length of the neck 160, the greater the cooling of the glass.

[0180] Figure 2 An exemplary embodiment of a neck 160 connecting the electrofusion zone 110 to the flame fusion zone 120 is shown without limitation.

[0181] According to this exemplary embodiment, the transition from the electric melting area 110 to the chuck 160 is achieved by a sudden narrowing of the width and cross-section of the glass channel, for example here by a wall forming a 90° angle with the longitudinal axis A-A' of the melting furnace, and the transition from the chuck 160 to the flame melting area 120 is achieved, on the contrary, by a sudden widening of the cross-section of the glass channel, for example here also by a wall forming a 90° angle with the longitudinal axis A-A' of the melting furnace.

[0182] Alternatively, the angle at the inlet of the neck 160 can have a value greater than 90° so that the narrowing of the width is less abrupt and more gradual, and similarly, the value of the angle at the outlet of the neck 160 can be selected so that the widening is also less abrupt and more gradual along the longitudinal axis AA' of the melting furnace.

[0183] Advantageously, molten glass flowing through the neck 160 from upstream to downstream is withdrawn from the lower portion of the electromelting region 110 , ie, from the bottom where the glass is relatively “colder” than the glass in the region between the high convection electrodes 115 .

[0184] The neck 160 has a bottom 165 that is connected to the bottom 116 of the electric melting zone 100 of the hybrid melting furnace 10 .

[0185] Advantageously, the hybrid melting furnace 10 includes a glass “non-return” separation device 170 that is configured to prevent molten glass from flowing back from the flame melting zone 120 to the electric melting zone 110 .

[0186] The separation device 170 is located at the neck 160, that is, between the electric melting area 100 and the flame melting area 120, to ensure a non-return function of the glass.

[0187] Advantageously, depending on the operating mode of the hybrid melting furnace 10, the separation device 170 can prevent glass from returning to the electric melting zone 110 regardless of whether the electric melting zone 110 is in use.

[0188] Several examples of such "non-return" glass separation devices 170 are described below.

[0189] according to Figure 3 The first example shown in detail shows the Figure 1 and 2 The neck 160 of the mixing furnace 10 of the first embodiment forms a “non-return” glass separation device 170 through at least one protrusion 161 on the bottom 165 of the neck 160 .

[0190] Preferably, the protrusion 161 includes at least a first rising portion 164 , a second platform segment 166 and a third descending portion 168 in sequence from upstream to downstream.

[0191] Advantageously, the projection 161 extends transversely over the entire width of the neck 160 .

[0192] Of course, such a protuberance 161 may have many geometrical variations in its general shape, its dimensions, and in particular according to the configuration of each of the different sectors 164 , 166 and 168 that constitute it.

[0193] Preferably, the rising section 164 is inclined at a certain angle (α) to form a slope that enables the molten glass to rise toward the platform section 166 of the protrusion 161, such as Figure 3 shown.

[0194] Preferably, the rising section 164 is an inclined plane having an acute angle (α) of, for example, between 20° and 70°, wherein the angle (α) is expressed as the angle between the rising section 164 of the protrusion 161 and the horizontal plane, here with reference to the flat bottom 116 of the electrofusion zone 110.

[0195] As a variant (not shown), the ascending section 164 is stepped, for example having at least one step or even having two or more steps, the height and / or length dimensions of which may be the same or different.

[0196] Preferably, the platform segment 166 is planar, forming a horizontal platform.

[0197] Advantageously, the platform section 166 thus extends longitudinally over a given length, preferably here greater than or equal to half the total length of the collar 160 .

[0198] The platform section 166 determines the maximum height H1 of the protrusion 161 , and this determines the passing cross section of the molten glass in the neck 160 .

[0199] The descending section 168 of the projection 161 extends vertically and is connected at a right angle to the downstream end of the flat platform section 166 extending horizontally.

[0200] Or, and if Figure 4 As shown, which will be described in the second example of the non-return separation device 170 below, the descending section 168 is configured to gradually follow the flow of molten glass from the chuck neck 160 toward the flame melting region 120 .

[0201] Such a section 168 is formed, for example, by an inclined plane which may or may not be stepped, in particular made stepped similarly to the description given above for the alternative embodiment of the rising section 164 .

[0202] Advantageously, the hybrid melting furnace 10 includes at least one atmosphere isolation device 174 capable of isolating the atmosphere of the cold top electric melting zone 110 from the atmosphere of the hot top flame melting zone 120 .

[0203] like Figure 3 As shown, the atmospheric pressure separation device 174 is formed by, for example, a diaphragm which is disposed at the neck 160 and vertically extends from the top, and whose lower free end is preferably in contact with the glass surface or even immersed in the glass.

[0204] Advantageously, the hybrid melting furnace 10 comprises a fixture 176 , also called a “skimmer”, capable of retaining the layer 112 of the vitrifiable mixture in the electromelting zone 110 , so that said vitrifiable mixture present on the surface of the glass bath 113 does not penetrate into the neck 160 .

[0205] Preferably, the means 176 for fixing the layer 112 is structurally separated from the separating means 174, and the fixing means 176 can be adjacent to or away from the separating means 174, such as Figure 3 shown.

[0206] Alternatively, the separation device 174 can perform not only the atmospheric separation function between the cold roof and the hot roof, but also the function of the fixing device 176.

[0207] Advantageously, the separation device 174 is then configured to be immersed in the glass melt pool 113 at its free end so as to keep the layer 112 of the vitrifiable mixture in the electromelting zone 110. Preferably, the separation device 174 is located at the upstream end of the neck 160 so that the layer 112 of the vitrifiable mixture present on the surface of the glass melt pool 113 does not penetrate into the downstream neck 160.

[0208] according to Figure 4 The second example shown and by Figure 3The first example in FIG. 1 is described below for comparison, and the glass non-return separation device 170 similarly includes at least one protrusion 161 of the bottom 165 of the neck 160 and a baffle 172 .

[0209] Advantageously, the projection 161 of the bottom 165 of the neck 160 has the same Figure 3 The shapes are substantially the same, that is, they are composed of an ascending section 164 , a platform section 166 and a descending section 168 in sequence.

[0210] However, Figure 4 The aforementioned variation is shown, in which the descending section 168 of the protrusion 161 is configured to gradually follow the molten glass flowing from the neck 160 toward the flame melting area 120. According to this variation, for example, the section 168 is formed by an inclined plane, which may or may not be stepped.

[0211] Advantageously, the baffle 172 is arranged above the platform section 166 of the protrusion 161 of the bottom 165 .

[0212] exist Figure 4 In the embodiment, the protrusion 161 of the bottom 165 has a height H2, which, as described above, is expressed relative to the horizontal plane of the flat bottom 116 of the electrofusion region 110 as a reference, and the height H2 is greater than Figure 3 The height H1 shown in FIG. 1 is relatively small.

[0213] As a result, the glass depth P2 between the surface S of the molten glass and the platform section 166 of the protrusion 161 of the bottom 165 is greater than Figure 3 Depth P1 in the example embodiment shown.

[0214] Preferably, baffle 172 associated with protrusion 161 is mounted so that it can be moved vertically to adjust its immersion depth in glass bath 113 so that the cross section of the glass passage between the free end of baffle 172 and platform portion 166 of protrusion 161 can be varied.

[0215] Alternatively, the baffle 172 is fixed so that the cross section of the glass passage is constant, that is, determined by the immersion depth of the baffle 172 in the glass melting pool 113 .

[0216] Preferably, the baffle 172 is removable, that is, detachable, so that it can be replaced or repaired, especially due to wear caused by contact with glass, thus facilitating maintenance of the mixing furnace 10.

[0217] The baffles 172 are made, for example, of a non-refractory metal or alloy, which can then be cooled by a cooling fluid cooling circuit (not shown), in particular a circuit of the water jacket type.

[0218] The baffles 172 then help cool the glass in the neck 160 by restricting flow in the neck 160 and due to the water jacket cooling fluid cooling circuit which removes some of the heat (calories) transferred by the glass to the baffles.

[0219] Alternatively, the baffle 172 is made of a refractory material, typically a ceramic, such as the fused refractory material "AZS" (an acronym for alumina-zircon-silica) or a refractory metal such as molybdenum.

[0220] According to a third example (not shown), the separation device 170 comprises only a baffle, advantageously identical to the baffle 172 just described, which is intended to be partially immersed in the bath 113 of molten glass.

[0221] Preferably, and Figure 4 Compared to the device of the second example shown, the baffle is located at the upstream end of the neck 160 , at the junction with the electrofusion zone 110 .

[0222] Preferably, the baffle extends transversely across the entire width of the neck 160 connecting the electrofusion zone 110 to the flame fusion zone 120 .

[0223] Advantageously, as described above, the baffle is mounted so that it can be moved vertically to adjust its immersion depth in the molten glass bath 113, or occupy a fixed position that determines a given glass passage cross section.

[0224] Advantageously, the baffle arranged upstream of the neck 160 is able to fix the layer 112 of the vitrifiable mixture covering the glass bath 113 in the electromelting zone 110, thus achieving the previously described Figure 3 The functionality of the fixture 176 is described to facilitate the elimination of such fixture 176 .

[0225] As previously Figure 4 As described in , the baffles are advantageously removable and, depending in particular on the type of material used for their construction, are cooled by a cooling fluid cooling circuit.

[0226] Advantageously, and in accordance with the above examples, the glass non-return separation device 170 comprises a baffle 172 and / or at least one protrusion 161 of the bottom 165 of the neck 160 that can be partially immersed in the molten glass.

[0227] Advantageously, the hybrid melting furnace 10 comprises a device 500 for cooling the glass, which is able to selectively cool the glass in the neck 160 .

[0228] In addition to cooling the glass as it flows through the neck 160 connecting the electric melting zone 110 and the downstream flame melting zone 120, the cooling device 500 can further enhance the cooling of the glass and, in particular, change the cooling, thereby regulating the glass temperature.

[0229] Preferably, the means 500 for cooling the glass in the neck 160 comprises at least one air circulation cooling device 510 .

[0230] The following are exemplary embodiments of the cooling device 510: Figure 3 and 4 As shown schematically in more detail in FIG.

[0231] Such an air cooling device 510 for glass includes, for example, an air inlet device 512 for introducing cooling air into the atmosphere of the neck 160 of the mixing furnace 10 at least.

[0232] Preferably, the means 510 for cooling the glass comprise exhaust means 514 arranged in the neck 160 to exhaust the hot air and ensure its renewal by fresh cooling air.

[0233] Alternatively, the exhaust means are formed by suction means (not shown) intended to extract the fumes, located downstream of the neck 160. Advantageously, the hot air is then exhausted together with the fumes through said suction means, without the hybrid furnace 10 having to be equipped with additional means.

[0234] The air inlet 512 and the air outlet 514 of the glass cooling device 510 are formed, for example, by one or more openings leading to the chest wall supporting the top of the neck 160 .

[0235] For example, the intake device 512 and the exhaust device 514 may be arranged laterally on either side of the neck 160 , or only on one side of the neck 160 .

[0236] The air inlet device 512 and the exhaust device 514 of the glass cooling device 510 can be arranged upstream of the atmosphere separation device 174, such as Figure 3 or even downstream, as shown Figure 4 shown.

[0237] Advantageously, the temperature of the cooling air introduced into the neck 160 is lower than the temperature of the hot air located inside the neck 160 , and the circulating cooling air forms a cooling fluid.

[0238] Preferably, the cooling air used is atmospheric air taken from outside the hybrid melting furnace 10, or even from outside the enclosure of the building in which said hybrid melting furnace 10 is installed.

[0239] Advantageously, the temperature of the atmospheric air used is controlled so that it can be regulated; for example, the air can be pre-cooled or reheated before being introduced to control its temperature, or even hygrometric.

[0240] Glass cooling is primarily accomplished by convection, whereby the introduced cooling air is heated upon contact with the glass surface and then removed along with the heat (calories) transferred by the glass.

[0241] Advantageously, the circulation of the air can be controlled by means of blowing means (not shown), such as a fan, associated with said suction and / or exhaust means, said blowing means being selectively controllable so as to vary the flow rate of the circulated air.

[0242] According to another embodiment, the device 500 for cooling the glass is immersed in the glass flowing from upstream to downstream through the neck 160 so as to allow it to cool.

[0243] Such cooling devices are formed, for example, by vertical columns immersed in the glass and cooled by a cooling circuit with a heat-transfer fluid in order to remove the heat transferred to the columns by the molten glass.

[0244] According to yet another embodiment, the cooling device 500 comprises a heat exchanger type cooling device, which also comprises a metal cooling device, which is arranged in the atmosphere surrounding the clamp neck 160, that is, above the glass surface, and through which a cooling fluid, typically water, flows to cool the air and thereby cool the molten glass.

[0245] Of course, cooling devices 500 associated with the neck 160, such as those according to the various examples just described, can be implemented alone or in combination.

[0246] Advantageously, the means 500 for cooling the glass, associated with the neck 160, make it possible to selectively control the temperature of the glass, which temperature may vary, in particular when the amount of pull varies, since an increase in the amount of pull results in an increase in the glass temperature.

[0247] Preferably, the glass cooling device 500 associated with the neck 160 is used when the electromelting zone 110 is also in use, ie, in the first electromelting operating mode or the second hybrid operating mode of the furnace.

[0248] As mentioned above, the electric melting area 100 is connected to the flame melting area 120 of the hybrid melting furnace 10 through the neck 160 .

[0249] The flame melting zone 120 includes at least an "overhead" burner 125 for melting the vitrifiable mixture that may be introduced by the second charging device 620, said overhead burner 125 being arranged above the surface S of the molten glass.

[0250] In a variant not shown, the hybrid melting furnace 10 comprises regulating means (not shown) such as electric assistance and / or a boiler, arranged in said flame melting zone 120 .

[0251] The flame melting zone 120 includes, for example, four overhead burners, which are Figure 1 and 2 It is schematically shown in FIG.

[0252] The overhead burners 125 are arranged transversely, and are therefore often referred to as "transverse burners", and are arranged, for example, on both sides of the flame melting zone 120, here shown facing each other, or preferably offset from each other so as not to face each other.

[0253] The mixing furnace 10 has at least one other burner 215 located downstream of the overhead burner 125, whose primary function is not to melt the vitrifiable mixture but to direct the glass.

[0254] Preferably, the hybrid melting furnace 10 has four overhead burners 215 , which are laterally distributed on both sides of the fining zone 200 like the burners 125 .

[0255] Melting of the vitrifiable mixture in the flame melting region 120 and selective heating of the glass in the refining region 200 are achieved by flames delivered by overhead burners 125 and burners 215 , respectively, which are fueled for this purpose and are generated by burning above the glass surface S.

[0256] This is why the burner 125 or 215 is called an "overhead" burner, as opposed to a "submerged" burner which is based on a completely different technology.

[0257] The boundary between the flame melting zone 120 and the fining zone 200 shown in the figure is schematic and not limiting. In practice, the boundary is not a fixed line, but a variable line, depending on the amount of pull and the operating mode of the melting furnace, and the boundary conventionally corresponds to the dividing line between the presence and absence of vitrifiable mixture on the surface of the glass bath.

[0258] Advantageously, the flame melting zone 120 extends along the longitudinal axis (A-A′) of the melting furnace for a length (L) that further determines the maximum amount of pull that can be produced by the flame melting zone 120 .

[0259] We will now describe Figure 1 and Figure 2 As shown in FIG. 1 , a fining zone 200 and a cooling zone 300 are provided after the melting zone 100 of the hybrid melting furnace 10 according to the first embodiment.

[0260] The fining zone 200 of the hybrid melting furnace 10 is configured to eliminate bubbles (or gas defects) present in the molten glass from the electric melting zone 100 and / or the flame melting zone 120 to obtain high-quality glass, and this advantageously enables the supply of float glass units.

[0261] To this end, the clarification zone 200 is configured to include a first convection circuit 210 , referred to as an upstream recirculation circuit, and a second convection circuit 220 , referred to as a downstream recirculation circuit.

[0262] Preferably, the first convection loop 210, referred to as the upstream recirculation loop, is longitudinally shorter than the second convection loop 220, such as Figure 1 shown.

[0263] Advantageously, the convection currents in the glass corresponding to the loops 210, 220 agitate the glass, eliminate bubbles and increase the residence time of the glass in the fining zone 200, thereby contributing to obtaining high quality glass.

[0264] Advantageously, the flame melting zone 120 of the hybrid melting furnace 10 is traversed by said first convection circuit 210 of the fining zone 200 .

[0265] In the second mixing operating mode, the first convection loop 210 thus also participates in mixing the molten glass delivered by the electric melting zone 110 and the flame melting zone 120 used together.

[0266] The first and second convection loops 210, 220 are separated by a temperature inversion zone 230 of the loops 210, 220, which is defined by a hot spot (also referred to as a "source spot") corresponding to the hottest point of the glass in the fining zone 200, typically at a temperature greater than 1500°C.

[0267] Advantageously, the burners 215 are arranged below the ceiling 240 of the refining zone 200 in order to obtain said hot spots defining the temperature inversion zones 230 of said circuits 210 , 220 .

[0268] In the fining zone 200 of the melting furnace, part of the heat energy released by the combustion is transferred directly to the glass by radiation and convection, and another part is transferred through the top 240, which returns the heat energy to the glass by radiation and for this reason is specifically called the "hot top".

[0269] Advantageously, the hybrid furnace 10 features a ridge 260 in the loop temperature inversion zone 230. Preferably, the ridge 260 extends vertically from the bottom 250 of the fining zone 200.

[0270] like Figure 1As shown, the ridge 260 includes a platform portion that is submerged below the glass surface S, defining the passage of the glass from a first convection loop 210, referred to as the upstream recirculation loop, toward a second convection loop 220, referred to as the downstream recirculation loop.

[0271] Preferably, the hybrid melting furnace 10 includes a regulating device (not shown) such as an electric assist and / or a boiler, which is arranged in the flame melting zone 120 and / or the fining zone 200, which enables the convection of the circuits 210, 220 to be adjusted so as to facilitate the glass manufacturing process.

[0272] Thus, advantageously, the conditioning means comprise electric assistance, ie additional electric heating means comprising electrodes and / or a boiler, ie a system for injecting at least one gas (for example air or nitrogen) at the bottom, the bubbles of which then move the glass upwards.

[0273] Preferably, the hybrid melting furnace 10 comprises at least one depth variation 270 of the bottom 250 of the fining zone 200 relative to the surface S of the glass.

[0274] The depth variation 270 is located in the portion including the first convection loop 210 and / or in the portion including the second convection loop 220 .

[0275] Advantageously, the depth modification 270 of the glass is, for example, Figure 1 The depth variation 270 is formed by at least one elevation of the bottom 250 shown, or by at least one height difference of the bottom 250 .

[0276] The elevation of the bottom 250 which forms the depth variation 270 , ie here a reduction in depth, is formed, for example, by at least one step 272 or even two steps.

[0277] Depth variation 270 may be more or less gradual, for example via a straight section 274 in the case of upstream of ridge 260 , or via an oblique section 276 in the case of a step 322 downstream of ridge 260 at the junction of fining zone 200 and glass cooling zone 300 .

[0278] Preferably, the cooling area 300 further includes a depth variation 370 formed by a protrusion including, for example, a step 322 leading from the bottom 250 to the inclined portion 276 and another step 332 downstream of the step 322. The step 322 is also gradually connected to another step 332 through the inclined portion 376.

[0279] Alternatively, just refer to Figure 1 The respective straight and inclined portions described may be reversed between the step 272 on the one hand and the steps 322, 332 on the other hand, or simply be of the same type, ie either straight or inclined.

[0280] like Figure 1 As shown, and as just described in successive steps 322 and 332 , the cooling zone 300 includes a bottom 350 that is configured such that the depth relative to the glass surface S gradually decreases from the ridge 260 from upstream to downstream.

[0281] The glass cooling zone 300 of the hybrid melting furnace 10 is passed through a second convection loop 220, referred to as the downstream circulation loop.

[0282] The cooling zone 300 is formed by a regulating tank furnace 310 communicating with at least one flow channel 400 intended, for example, to supply high quality glass to a forming zone located downstream and preferably consisting of a float glass unit on a bath of molten metal (not shown).

[0283] Advantageously, the regulating tank kiln 310 of the cooling zone 300 comprises, from upstream to downstream, a further neck 320 , called the second neck, and then a working end 330 .

[0284] Advantageously, the atmosphere of the refining zone 200 and the cooler atmosphere of the cooling zone 300 are separated from each other by a heat shield 360 extending vertically from the top 340 to near the glass surface S, preferably without tempering the glass.

[0285] Advantageously, in any vertical plane transverse to the longitudinal axis AA′ of the mixing furnace 10 , there is a point in the regulating tank furnace 310 that has a longitudinal velocity component in the glass from downstream to upstream.

[0286] After the conditioning tank furnace 310, no backflow occurs in the flow channel 400 intended for supplying glass to the forming area, in other words, the glass flow in the channel 400 is a "plug" flow.

[0287] Advantageously, the hybrid melting furnace 10 according to the invention is capable of delivering high quality glass with less than 0.1 bubbles per litre, preferably less than 0.05 bubbles per litre, which high quality glass is most particularly suitable for supplying float glass units intended for the production of flat glass.

[0288] Advantageously, the hybrid furnace 10 is capable of supplying high quality glass having less than 0.1 bubbles per liter to a float glass unit on a molten metal bath at a nominal pull of greater than or equal to 400 tons / day, preferably 600-900 tons / day, or even 1000 tons / day or more.

[0289] Preferably, the hybrid melting furnace 10 for manufacturing glass according to the present invention supplies a float glass unit on a molten metal such as a tin bath through the flow channel 400 for manufacturing flat glass.

[0290] According to the present invention, and as described above, the hybrid melting furnace 10 according to the first embodiment is also characterized in that it includes an electric melting zone 110 and a flame melting zone 120 which can be operated independently of each other, thereby providing energy flexibility to the hybrid melting furnace 10 .

[0291] In the hybrid melting furnace 10 according to the invention, energy flexibility refers to the energy used for the melting phase of the vitrifiable mixture, which is the most energy-intensive phase of the glass manufacturing process.

[0292] Advantageously, the electrode 115 constitutes the heating means of the electric melting zone 110 for melting the vitrifiable mixture, while the burner 125 preferably constitutes the only heating means of the flame melting zone 120. Alternatively, when an auxiliary electric heating means comprising an immersed electrode is used, the burner 125 constitutes the main heating means.

[0293] Due to this design of the melting zone 100 of the hybrid melting furnace 10, one of the above three operating modes can be selected, namely a first electric melting operating mode, a second so-called hybrid operating mode and a third flame melting operating mode.

[0294] Advantageously, the electric melting zone 110 is capable of providing a maximum draw that is less than or equal to the nominal draw of the furnace, ie, between 0% and 100% of the nominal draw.

[0295] Preferably, the electrofusion zone 110 is capable of delivering up to 100% of the maximum pull amount, so that the nominal pull amount can be obtained by electrofusion alone, typically in the first operating mode.

[0296] Advantageously, the flame melting zone 120 is capable of providing a maximum draw less than or equal to the nominal draw of the furnace, i.e., between 0-100% of the nominal draw, preferably up to 100%, so that the nominal draw can be obtained only by flame melting, typically in the third operating mode.

[0297] Preferably, the flame melting zone 120 is capable of providing a maximum pull between 0% and 50% of the nominal pull. Therefore, in order to achieve the nominal pull, the electromelting zone 110 must be used in combination with the flame melting zone 120 to achieve 100%, which will be the case in the second hybrid operating mode.

[0298] In the hybrid melting furnace 10 according to the invention, the energy used for melting the vitrifiable mixture will therefore depend on the selected operating mode, which can in particular be determined based on the desired draw relative to the nominal draw of the hybrid melting furnace 10 .

[0299] Preferably, the vitrifiable mixture is fully or partially melted in the electric melting zone 110 of the hybrid melting furnace 10, so that melting is thus achieved only using electrical energy according to a first electric melting operation mode, or mainly using a combination of electrical energy and fuel according to a second hybrid operation mode.

[0300] Advantageously, electricity accounts for more than 60%, or even 80% and even more, of the total energy used by the hybrid melting furnace 10 during the glassmaking process (and particularly for melting the vitrifiable mixture, which is the most energy intensive stage of the process).

[0301] Indeed, as explained in the preamble, efforts are underway to reduce the carbon footprint of the glass manufacturing process.

[0302] Thus, when the fuel energy is a fossil fuel such as natural gas, and the electrical energy by contrast is wholly or partially "green" electricity obtained from renewable and decarbonized energy, then electricity is generally preferred for at least this reason.

[0303] However, while electricity may be the preferred energy source for melting, the hybrid furnace 10 also provides a third operating mode using fuel flame melting, which ensures that glass can always be made, even in the event of energy problems, for example, avoiding any forced shutdown of the hybrid furnace 10.

[0304] As is known, the hybrid melting furnace 10 may include regenerators (e.g., in pairs and inverted) operated from refractory materials, or metal exchangers, which respectively utilize the heat contained in the flue gases generated during the manufacturing process to preheat the fluids (fuel and oxidant) supplied to the burners 125 and / or 215 and thereby improve combustion.

[0305] Overhead burner 125 (and burner 215) produces a flame by combustion, which can be obtained by combining different types of fuels and oxidants, but its selection also has a direct impact on the carbon footprint of glass manufacturing, or the direct and indirect emissions of greenhouse gases associated with product manufacturing, particularly carbon dioxide emissions (CO2).

[0306] However, while the most commonly used fuel in burner 125 is gas, the carbon footprint of the glass manufacturing process can be further improved by using "green fuels", particularly "biogas", preferably "biomethane" (CH4).

[0307] "Biogas" is a gas consisting essentially of methane and carbon dioxide, produced by methanogenesis, the fermentation of organic matter under anaerobic conditions.

[0308] Hydrogen (H2) is even more preferred for use as a fuel because it is advantageously carbon-free compared to biogas and has no carbon and no carbon dioxide (CO2) emissions.

[0309] For combustion by burners 125 and 215, oxygen present in air is generally used as the oxidant, however, the air may be enriched with oxygen to obtain oxygen-enriched air, or even use substantially pure oxygen in the specific case of oxy-fuel combustion.

[0310] As mentioned above, the fluids (fuel and oxidant) supplying the burners 125, 215 may be preheated to improve combustion, in particular by utilizing heat contained in the flue gases from the manufacturing process via a metal exchanger.

[0311] Advantageously, the energy flexibility obtained with the hybrid melting furnace 10 according to the invention is thus total, making it possible to choose the energy or energies used for melting, as well as the ratio in which they are used.

[0312] Advantageously, the selection of one of the three operating modes of the hybrid melting furnace 10 is based on at least one selection parameter, for example, comprising:

[0313] - economic criteria, which are based on the respective costs of electrical energy and fuel for further melting of the vitrifiable mixture;

[0314] - ecological criteria based on the carbon footprint (CO2) associated with electricity and said fuels respectively, and

[0315] - at least one technical criterion based on the draw volume to be produced in relation to the amount of molten glass obtainable by the at least one electric melting zone 110 and / or flame melting zone 120 and / or based on the composition of the glass to be produced, or even based on the cullet content of the vitrifiable mixture.

[0316] Advantageously, the hybrid melting furnace 10 can be controlled by an associated control unit (UC), in particular by the control unit (UC) to select the respective Figures 5 to 7 One of the operating modes is shown in , which will be described below.

[0317] Figure 5 The hybrid melting furnace 10 according to the first embodiment is shown in a first electromelting operation mode.

[0318] In this electromelting solution, glass is produced only in the electromelting region 110 by means of the electrodes 115 , wherein the vitrifiable mixture is supplied to said region 110 by means of the first feeding device 610 .

[0319] The second charging device 620 associated with the flame melting zone 120 is in a stationary state, which is why the arrow schematically illustrating it has been shown as a dashed line.

[0320] like Figure 5As shown, the vitrifiable mixture is advantageously evenly distributed over the surface of the molten glass bath 113 in a layer 112 , said layer being held by the above-mentioned fixing means 176 so as not to penetrate the neck 160 .

[0321] In this first electromelting operating mode, without flame melting by means of the overhead burner 125 , the second charging device 620 is in a stationary state, so that no vitrifiable mixture is delivered to the flame melting zone 120 .

[0322] The molten glass produced in the electric melting area 110 flows longitudinally from upstream to downstream, and the separation device 170 arranged at the neck 160 advantageously prevents any return of the glass to the electric melting area 110 .

[0323] Thus, the molten glass flows from the electric melting zone 110 through the neck 160 to the flame melting zone 120 and then to the refining zone 200 where the glass is refined by circulating along the first convection loop 210 .

[0324] In the first electric melting operation mode, if no fuel is used in the burner 125 to melt the vitrifiable mixture, the glass surface is selectively heated by a flame from at least one burner 215 in the clarification zone 200 to obtain a hot spot, thereby improving the clarification and homogenization of the glass by eliminating bubbles (or gas defects) present in the molten glass.

[0325] Advantageously, by adjusting the power of a portion of the at least one burner 215 located downstream near the ridge 260, it is possible to adjust the longitudinal distribution of temperature and, therefore, the location of the hot spot, which is an important parameter for the operation of the furnace.

[0326] The glass then passes through the ridges 260 at the loop temperature inversion region 230 , enters the second convection loop 220 from the first convection loop 210 , and travels along the second convection loop 220 through the cooling region 300 .

[0327] In the cooling area 300 , the glass circulating along the second convection loop 220 passes through the second clamping neck 320 , and then passes through the working end 330 , and then finally leaves the mixing furnace 10 through the glass flow channel 400 .

[0328] Figure 6 The hybrid melting furnace 10 according to the first embodiment is shown in a second hybrid operation mode, which will be described below with reference to FIG. Figure 5 Describe by comparison.

[0329] In the second hybrid melting furnace operation mode, the electric melting zone 110 and the flame melting zone 120 are used to obtain molten glass at the same time, and the results are two different energy sources, electricity and fuel, respectively.

[0330] However, the ratio of electricity to fuel is advantageously freely parameterizable, in particular depending on the above-mentioned selection criteria and within the limits of the maximum possible draw per melting zone 110 , 120 relative to the nominal draw of the hybrid furnace 10 .

[0331] In this way, the electricity used to power the electrode 115 and the fuel used to power the overhead burner 125 can be used in equal proportions, or in a 50 / 50 ratio, or in any other ratio.

[0332] Preferably, electricity predominates over fuel, such as a 60 / 40 ratio, or even an 80 / 20 ratio (ie, 80% electricity and 20% fuel).

[0333] Alternatively, fuel may also be preferred to electricity, in particular for ecological reasons based on their respective carbon footprint (CO2); for example, the fuel is advantageously formed from hydrogen (H2) or even biogas, while the electricity is not produced from renewable and decarbonized energy, but from fossil fuels such as coal.

[0334] like Figure 6 As shown, the vitrifiable mixture is present in the electric melting zone 110 and the flame melting zone 120, each provided by a first feeding device 610 and a second feeding device 620, respectively, including a first intermittent feeder 622 and a second intermittent feeder 624, which are arranged transversely in this first embodiment.

[0335] As mentioned above Figure 5 As described above, the molten glass produced by the electric melting area 110 flows through the chuck 160, but this molten glass is then mixed with the molten glass produced by the flame melting area 120; then, the molten glass obtained from the mixture circulates to the clarification area 200 along the first convection loop 210.

[0336] Since the electric melting zone 110 and the flame melting zone 120 are arranged in series, the molten glass produced by the zone 110 flows into the downstream flame melting zone 120 for mixing.

[0337] Advantageously, the neck 160 including the separation device 170, or even a cooling device 500 such as an air circulation cooling device 510, can also be used to control the flow, in particular the temperature of the glass.

[0338] The path of the molten glass from the fining area 200 through the cooling area 300 to the channel 400 is similar to that described above with reference to Figure 5 The path described is the same, so reference may be made to that path without repeating it here.

[0339] Figure 7The hybrid melting furnace 10 according to the first embodiment is shown in the third flame melting operation mode, which will be described below by referring to Figure 6 The patterns are described by comparison.

[0340] In this third operating mode, molten glass is produced only by the flame melting zone 120, and thus the unused electric melting zone 110 is not supplied with a vitrifiable mixture by the first charging device 610 which is at rest as indicated by the dashed arrow.

[0341] To this end, Figure 7 In the above Figure 5 and 6 In contrast, no layer 112 of the vitrifiable mixture is visible in the electrofusion region 110 .

[0342] The vitrifiable mixture is introduced laterally into both sides of the flame melting zone 120 through the first intermittent feeder 622 and the second intermittent feeder 624 of the second feeding device 620 forming the mixing melting furnace 10, respectively.

[0343] The melting of the vitrifiable mixture is achieved thanks to the flame generated by the burner 125 during the combustion of a fuel, which advantageously consists of hydrogen (H 2 ) or even biogas such as biomethane (CH 4 ).

[0344] The obtained molten glass circulates along a first convection loop 210 extending longitudinally between the flame melting zone 120 and the fining zone 200 .

[0345] Advantageously, the molten glass remains in the flame melting region 120 and does not enter the choke 160 located upstream, ie in the direction of the electric melting region 110 , in particular due to the glass non-return separation device 170 .

[0346] like Figure 3 and 4 As shown and described above, the glass check separator 170 advantageously includes a baffle 172 and / or at least one protrusion 161 of the bottom 165 of the neck 160 that can be partially immersed in the molten glass.

[0347] The absence of electrofusion in this third flame operating mode does not necessarily mean a complete shutdown of the electrofusion zone 110 .

[0348] Preferably, the electrode 115 keeps being supplied with electricity to maintain the temperature above the devitrification temperature in the electric melting region 110. However, if the first charging device 610 does not introduce a vitrifiable material, molten glass is not produced.

[0349] Advantageously, maintaining such a temperature in the electrofusion zone 110 thus corresponds to a standby mode that enables a faster transition to the first electrofusion operating mode or the second hybrid operating mode.

[0350] Alternatively, if prolonged operation in the third mode is planned, the electric melting zone 110 may be turned off. Preferably, a device such as a baffle 172 is then provided in the neck 160 to keep the glass in the flame melting zone 120.

[0351] As before Figure 6 As shown, the path of the molten glass from the clarification area 200 through the cooling area 300 to the channel 400 is similar to the previous reference Figure 5 The same are described, so reference can advantageously be made thereto.

[0352] The following is a comparison with the first embodiment. Figures 8 to 12 A description of a second embodiment of a hybrid melting furnace 10 according to the present invention is shown.

[0353] In the second embodiment, the hybrid melting furnace 10 includes a melting zone 100 having at least a first electric melting zone 110A and a second electric melting zone 110B.

[0354] In the second embodiment, the hybrid melting furnace 10 preferably includes two electric melting zones, 110A and 110B, respectively; alternatively, the hybrid melting furnace 10 may include more than two electric melting zones.

[0355] Compared to the first embodiment, in which the hybrid melting furnace 10 has a single electric melting zone 110, the fact that there are at least two or more electric melting zones in this second mode further provides various advantages.

[0356] Depending on the amount of pull to be delivered during the electrofusion process, it may be advantageous to choose to use only one of the electrofusion regions 110A and 110B.

[0357] Furthermore, it is also possible to use only one of the electrofusion zones, for example when maintenance or other operations have to be performed in the other of the electrofusion zones.

[0358] Advantageously, the electrofusion zones 110A and 110B are designed to be used together.

[0359] Advantageously, the two electrofusion zones 110A and 110B have a similar design as the electrofusion zone 110 described above for the first embodiment and therefore will not be described in detail.

[0360] The two electric melting areas 110A and 110B of the hybrid melting furnace 10 also include electrodes 115, wherein for example Fig. 9 There are six electrodes in each zone shown.

[0361] In the second embodiment, each of the zones 110A and 110B has a surface area that is smaller than the surface area of ​​the molten zone 110 of the first embodiment.

[0362] Preferably, the electrode 115 is arranged on the surface so as to be immersed in the vitrifiable mixture, the immersed electrode 115 extending vertically.

[0363] Preferably, the electrofusion zones 110A and 110B are capable of delivering a pull amount greater than or equal to that of the electrofusion zone 110 of the first embodiment.

[0364] Advantageously, said electromelting zones 110A and 110B are capable of delivering a maximum draw less than or equal to the nominal draw of the furnace, ie between 0% and 100%, preferably at most 100%, of the nominal draw so that said nominal draw can be obtained by electromelting alone.

[0365] like Fig. 9 As shown, the first electric melting region 110A and the second electric melting region 110B are laterally arranged on both sides of the flame melting region 120 .

[0366] Preferably, the first electric melting zone 110A and the second electric melting zone 110B are arranged orthogonal to the longitudinal axis (AA') of the melting furnace.

[0367] Advantageously, the first feeding device 610 comprises a first intermittent feeder 612 for feeding the vitrifiable mixture to the first electro-melting region 110A and a second intermittent feeder 614 for feeding the vitrifiable mixture to the second electro-melting region 110B.

[0368] The first intermittent feeder 612 and the second intermittent feeder 614 are Figures 9 to 12 The first intermittent feeder 612 and the second intermittent feeder 614 are arranged transversely to supply the vitrifiable mixture to the first electro-melting region 110A and the second electro-melting region 110B, respectively.

[0369] Advantageously, the first intermittent feeder 612 and the second intermittent feeder 614 forming the first feeding device 610 are configured to spread the vitrifiable mixture in a uniform layer 112 on the surface of the molten glass pool 113 in each of the first and second electric melting zones 110A and 110B.

[0370] Advantageously, the electric melting zones 110A and 110B are arranged in series with the flame melting zone 120 so that the molten glass produced by each of the melting zones 110A and 110B flows into the flame melting zone 120 located downstream.

[0371] The first electric melting region 110A and the second electric melting region 110B are connected to the flame melting region 120 through the first neck 160A and the second neck 160B, respectively.

[0372] Advantageously, the first neck 160A and the second neck 160B are identical to the neck 160 according to the first embodiment and will therefore not be described in further detail.

[0373] Advantageously, the hybrid melting furnace 10 comprises a glass non-return separation device 170 in each of said necks 160A and 160B.

[0374] Preferably, each separation device 170 comprises as described with reference to the first embodiment. Figure 3 At least one protrusion 161 of the bottom 165 is described.

[0375] Advantageously, the hybrid melting furnace 10 further comprises, in each of said first neck 160A and said second neck 160B, an atmospheric separation device 174 and a fixture 176 suitable for holding the vitrifiable mixture.

[0376] Advantageously, the hybrid melting furnace 10 comprises a cooling device 500, preferably an air cooling device 510, which is the same as described above for the first embodiment, Figures 8 to 12 Not shown schematically.

[0377] Preferably, the second feeding device 620 for supplying the vitrifiable mixture to the flame melting zone 120 comprises at least one screw intermittent feeder.

[0378] like Fig. 9 As shown, the second charging device 620 is arranged longitudinally opposite to the melting furnace, ie, along the longitudinal axis (AA′) of the melting furnace, upstream of the flame melting zone 120 .

[0379] In addition to the vitrifiable mixture feeding device 620, the hybrid melting furnace 10 according to the second embodiment includes a flame melting zone 120, which includes the same overhead burners 125 as described above for the first embodiment, and will therefore be described with reference to that embodiment.

[0380] The hybrid melting furnace 10 includes a fining zone 200 and a cooling zone 300 which are respectively the same as those of the first embodiment. It is advantageous to refer to the description of the first embodiment. Figures 8 to 12 The same reference numerals are used for this purpose.

[0381] exist Figures 8 to 12In the second embodiment shown, the first electric melting zone 110A and the second electric melting zone 110B are arranged laterally on both sides of the flame melting zone 120 .

[0382] Alternatively, the first electric melting zone 110A and the second electric melting zone 110B are arranged longitudinally one after another upstream of the flame melting zone 120, wherein the clamping necks 160A, 160B extend parallel to the longitudinal axis (A-A') of the melting furnace or obliquely, i.e., at a given acute angle to the longitudinal axis (A-A').

[0383] In this embodiment, the second charging device 620 is arranged transversely relative to the flame melting zone 120, preferably orthogonal to the longitudinal axis (A-A').

[0384] Preferably, the second feeding device 620 includes: Figure 2 The first and second intermittent feeders 622, 624 in the first embodiment shown are arranged transversely, ie orthogonally to the longitudinal axis (AA') of the furnace, on either side of the flame melting zone 120 to which the vitrifiable mixture is to be supplied.

[0385] Advantageously, the hybrid melting furnace 10 according to the second embodiment can be operated in several operating modes, which also provides energy flexibility.

[0386] As in the first embodiment, the hybrid melting furnace 10 is characterized by a first electric melting mode, a second hybrid mode, and a third flame melting mode, respectively.

[0387] Advantageously, the hybrid melting furnace 10 may be composed of Figure 8 A control unit (UC) schematically shown in FIG. 1 controls so as to select one of the operating modes according to at least one of the above-mentioned selection parameters, namely an economic criterion, an ecological criterion and at least one technical criterion.

[0388] Fig.11 The hybrid melting furnace 10 according to the second embodiment of the present invention is shown in a second electric melting operation mode, wherein molten glass is produced by electric melting only, ie, with electricity as energy source, without using the flame melting zone 120 .

[0389] As a result, the overhead burner 125 and the second charging device 620 associated with the flame melting zone 120 are both in a static state, as shown by the absence of flames and the use of dashed lines as arrows, respectively.

[0390] like Fig.11As shown, the first and second electrofused regions 110A, 110B are covered, preferably uniformly, with a layer 112 of a vitrifiable mixture, which is retained by a fixture 176 extending longitudinally upstream of the first and second necks 160A, 160B.

[0391] Thus, the first electro-melting region 110A and the second electro-melting region 10B are supplied with the vitrifiable mixture only from the first melting furnace 612 and the second melting furnace 614, respectively.

[0392] The molten glass produced by the first and second electric melting zones 110A and 110B, respectively, will flow laterally through the first and second necks 160A and 160B to the flame melting zone 120 through which the first convection loop 210 of the fining zone 200 passes.

[0393] Then, the molten glass passes through the fining zone 200 and the cooling zone 300 to reach the flow channel 400 .

[0394] Since the first operating mode of electric melting in the hybrid melting furnace 10 according to this second embodiment is otherwise similar to the previous reference Figure 5 This is the same as described for the first mode and will therefore not be described in further detail.

[0395] Fig.12 The hybrid melting furnace 10 according to the second embodiment of the present invention is shown in a second hybrid operation mode, wherein melting of the vitrifiable mixture is performed together in the first and second electric melting zones 110A and 110B and the flame melting zone 120 .

[0396] like Fig.12 As shown, two electrofused regions 110A and 110B and a flame fused region 120 are covered with a layer 112 of a vitrifiable mixture.

[0397] The first electric melting zone 110A and the second electric melting zone 110B are fed by the first intermittent feeder 612 and the second intermittent feeder 614 respectively, while the flame melting zone 120 is fed longitudinally by the second feeding device 620 upstream of the mixing melting furnace 10.

[0398] In this hybrid operation mode, a portion of the molten glass produced by the first electromelting region 110A and the second electromelting region 110B is thus obtained by electricity, while another portion is obtained by using fuel in the overhead burner 125 to produce Fig.12 obtained by the flame shown.

[0399] In contrast to the first embodiment, a third embodiment of the flame melting operation is not shown in the figures.

[0400] With the above Fig.12 In comparison, the flame melting operation mode differs in that melting is achieved by the overhead burner 125, which is here achieved only by the burner 125 without an auxiliary electric heating device, without using the first electric melting zone 110A and the second electric melting zone 110B.

[0401] Figures 1 to 7 The first embodiment shown and Figures 8 to 12 The second embodiment shown is given merely as a non-limiting example of the invention.

[0402] The invention relates to a hybrid melting furnace 10 for producing glass, in particular for supplying floating units, said hybrid melting furnace 10 having a longitudinal axis (A-A') and comprising:

[0403] at least one electrofusion zone 110 comprising an electrode 115 adapted to be supplied with a vitrifiable mixture via a first feeding device 610;

[0404] a flame melting zone 120 comprising at least an overhead burner 125 which can be supplied with a vitrifiable mixture by means of a second feeding device 620 separate from the at least one first feeding device 610,

[0405] The at least one electric melting zone 110 and the flame melting zone 120 arranged in series are configured to be independently operable to allow selective use of either or both of the melting zones 110 , 120 , thereby providing energy flexibility for the melting furnace 10 .

[0406] Advantageously, the hybrid melting furnace 10 according to the invention is capable of supplying a float glass unit (not shown).

[0407] According to another aspect, the invention relates to an assembly for manufacturing flat glass, comprising a hybrid glassmaking furnace 10 and a float glass unit on a molten metal bath, arranged downstream, supplied with glass by said furnace 10 through said at least one flow channel 400 .

[0408] According to a further aspect, the invention relates to a method for producing glass implemented in a hybrid melting furnace 10 according to the invention, in particular for supplying a float glass unit on a bath of molten metal.

[0409] The method for producing glass comprises at least one melting step carried out in a hybrid melting furnace 10 operated according to one of the above-mentioned operating modes of the hybrid melting furnace, i.e., selectively selected from:

[0410] a first electromelting operation mode, in which molten glass is produced only by the at least one electromelting zone 110;

[0411] - a second hybrid operation mode, in which molten glass is produced by both the at least one electric melting zone 110 and the flame melting zone 120;

[0412] A third flame-melting operating mode, in which molten glass is produced only by the at least one flame-melting zone 120 .

[0413] Advantageously, before carrying out the melting step in the mixed melting furnace, the method for producing glass comprises at least one operating mode determination step, which operating mode determination step consists in selecting one of the melting furnace operating modes based on at least one selection parameter, such as the economic criteria and / or ecological criteria and / or at least one technical criterion as respectively described above.

[0414] Thus, the determination step consists in selecting one of the operating modes based on at least one selection parameter, the at least one selection parameter comprising:

[0415] - economic criteria, which are based on the respective costs of electrical energy and fuel for further melting of the vitrifiable mixture;

[0416] - ecological criteria based on the carbon footprint (CO2) associated with electricity and said fuels respectively, and

[0417] - at least one technical criterion based on the draw volume to be produced in relation to the amount of molten glass obtainable by the at least one electric melting zone 110 and / or flame melting zone 120 and / or based on the composition of the glass to be produced, or even based on the cullet content of the vitrifiable mixture.

[0418] Advantageously, said determination step for selecting one of the operating modes of the hybrid melting furnace 10 is performed by a control unit (UC) associated with the hybrid melting furnace 10 .

[0419] Advantageously, when the second hybrid operating mode is selected at the end of the determination step, the method comprises an additional determination step, which consists in determining the amount of molten glass to be produced by the at least one electric melting zone 110 and by the flame melting zone 120, respectively, in order to obtain the desired pulling amount.

[0420] The further determining step also determines the respective phase contributions of the at least one electric melting zone 110 and the flame melting zone 120, for example determining a ratio of 50 / 50, or even a ratio of 80 / 20 when the electrical energy 5 is superior to the fuel.

[0421] Preferably, the desired pulling amount is equal to the nominal pulling amount of the hybrid melting furnace 10 .

[0422] Advantageously, the control unit (UC) determines control parameters of the respective melting furnace, in particular control parameters of the electrode 115 and / or the overhead burner 125, and also determines control parameters of the first feeding device 610 and / or the second feeding device 620, in order to adjust the amount of vitrifiable material to be added to the at least one electric melting zone 110 and / or flame melting zone 120 according to the operating mode of the melting furnace and to obtain the said pull amount.

Claims

1. A mixing furnace (10) for producing glass, in particular for supplying a unit for floating glass on a bath of molten metal, said mixing furnace (10) having a longitudinal axis (A-A') comprising: at least one electric melting zone (110) adapted to be supplied with a vitrifiable mixture by means of at least one first feeding device (610) and comprising electrodes (115) for melting the vitrifiable mixture; a flame melting zone (120) separated from the at least one electric melting zone (110), suitable for supplying a vitrifiable mixture via at least one second feeding device (620), and comprising at least an overhead burner (125) for melting the vitrifiable mixture, the overhead burner (125) being arranged above the surface (S) of the molten glass, wherein the at least one electric melting zone (110) and the flame melting zone (120) are arranged in series so that molten glass produced by one of the upstream melting zones (110) can flow into the other of the downstream melting zones (120), and wherein the at least one electric melting zone (110) and the flame melting zone (120) are configured to operate independently of each other so as to allow selective use of one and / or the other of the melting zones (110, 120) so as to provide energy flexibility for the melting furnace, a fining zone (200) for molten glass conveyed by the at least one electric melting zone (110) and / or the flame melting zone (120), the fining zone (200) being configured to include a first convection circuit (210) and a second convection circuit (220); and A zone (300) for cooling glass, comprising a conditioning tank (310) through which a second convection circuit (220) passes and which is connected to at least one glass flow channel (400).

2. The melting furnace according to claim 1, characterized in that: The at least one electromelting zone (110) is capable of delivering a maximum draw less than or equal to the nominal draw of the furnace, i.e. between 0% and 100%, preferably up to 100%, of the nominal draw so that the nominal draw can be obtained by electromelting alone.

3. The melting furnace according to claim 1 or 2, characterized in that: The electrode (115) is arranged on the surface so as to be immersed in the vitrifiable mixture, the immersed electrode (115) preferably extending vertically.

4. The melting furnace according to any one of claims 1 to 3, characterized in that The flame melting zone (120) is passed through a first convection circuit (210) of the fining zone (200).

5. The melting furnace according to any one of claims 1 to 4, characterized in that The flame melting zone (120) is capable of delivering a maximum pull amount that is less than or equal to the nominal pull amount of the melting furnace, i.e., between 0% and 100% of the nominal pull amount, preferably up to 100% so that the nominal pull amount can be obtained by flame melting alone, or even between 0% and 50% so that the nominal pull amount can be obtained by the combined use of flame melting and electric melting.

6. The melting furnace according to claim 5, characterized in that The flame melting zone (120) extends along the longitudinal axis (AA') of the melting furnace for a certain length (L), which further determines the maximum pull amount that the flame melting zone (120) can produce.

7. The melting furnace according to any one of claims 1 to 6, characterized in that The at least one electric melting zone (110) is connected to the flame melting zone (120) via a neck (160, 160A, 160B).

8. The melting furnace according to claim 7, characterized in that The hybrid melting furnace (10) comprises a so-called non-return separation device (170) arranged at the neck (160, 160A, 160B) and capable of preventing molten glass from returning from the flame melting zone (120) to the at least one electric melting zone (110).

9. The melting furnace according to claim 8, characterized in that The separation device (170) includes a baffle (172) intended for partial immersion in molten glass.

10. The melting furnace according to claim 8 or 9, characterized in that: The separating device (170) comprises at least one protrusion (161) on the bottom (165) of the neck (160, 160A, 160B).

11. The melting furnace according to any one of claims 7 to 10, characterized in that The mixed melting furnace (10) comprises at least one atmosphere separation device (174), which is arranged at the neck (160) and is capable of separating the atmosphere of the at least one electric melting area (110) having a cold top and the atmosphere of the flame melting area (120) having a hot top.

12. The melting furnace according to any one of claims 7 to 11, characterized in that The mixing furnace (10) includes a fixture (176) capable of holding the vitrifiable mixture in the at least one electric melting zone (110) so that the vitrifiable mixture present on the glass surface does not penetrate into the neck (160, 160A, 160B).

13. The melting furnace according to any one of claims 7 to 12, characterized in that The hybrid melting furnace (10) comprises a device (500) for cooling glass, in particular at least one air circulation cooling device (510), capable of cooling the glass in the neck (160).

14. The melting furnace according to any one of claims 1 to 13 in combination with claim 7, characterized in that The hybrid melting furnace (10) comprises an electric melting zone (110) connected to a downstream flame melting zone (120) via a neck (160).

15. The melting furnace according to claim 14, characterized in that A first feeding device (610) for supplying a vitrifiable mixture to the electromelting zone (110) is configured to spread the vitrifiable mixture in the form of a uniform layer (112) on the surface (S) of the molten glass.

16. The melting furnace according to claim 14 or 15, characterized in that The second feeding device (620) for supplying the vitrifiable mixture to the flame melting zone (120) includes a first intermittent feeder (622) and a second intermittent feeder (624), which are arranged laterally on both sides of the flame melting zone (120), preferably orthogonal to the longitudinal axis (A-A') of the melting furnace.

17. The melting furnace according to any one of claims 1 to 13 in combination with claim 7, characterized in that The mixed melting furnace (10) comprises at least a first electric melting area (110A) and a second electric melting area (110B), wherein the first electric melting area (110A) and the second electric melting area (110B) are connected to the flame melting area (120) via a first neck (160A) and a second neck (160B), respectively.

18. The melting furnace according to claim 17, characterized in that The first electric melting zone (110A) and the second electric melting zone (110B) are arranged transversely on both sides of the flame melting zone (120), preferably orthogonal to the longitudinal axis (A-A') of the melting furnace.

19. The melting furnace according to claim 17 or 18, characterized in that The first feeding device (610) includes a first intermittent feeder (612) for feeding the vitrifiable mixture to the first electromelting region (110A) and a second intermittent feeder (614) for feeding the vitrifiable mixture to the second electromelting region (110B).

20. The melting furnace according to any one of claims 17 to 19, characterized in that The second charging device (620) is arranged longitudinally upstream of the flame melting zone (120).

21. The melting furnace according to any one of claims 1 to 20, characterized in that The vitrifiable mixture introduced into the melting furnace via a first charging device associated with the at least one electric melting zone (110) and the vitrifiable mixture introduced into the melting furnace via a second charging device associated with the flame melting zone (120) have similar compositions.

22. The melting furnace according to any one of claims 1 to 21, characterized in that The hybrid melting furnace (10) is capable of operating according to several operating modes, the melting furnace operating modes being selectively selected from the following: - a first electromelting operation mode, in which molten glass is produced only by the at least one electromelting zone (110); - a second hybrid operating mode, wherein molten glass is produced jointly by the at least one electric melting zone (110) and the flame melting zone (120); - a third flame-melting operating mode, wherein molten glass is produced only by the at least one flame-melting zone (120).

23. The melting furnace according to claim 22, characterized in that The hybrid melting furnace (10) is controllable by an associated control unit (UC) to select one of the operating modes based on at least one selection parameter, the at least one selection parameter comprising: - an economic criterion based on the respective costs of the electrical energy and the fuel for further melting of the vitrifiable mixture; - ecological criteria based on the carbon footprint (CO2) associated with electricity and said fuels respectively, and - at least one technical criterion based on the draw volume to be produced in relation to the amount of molten glass obtainable by the at least one electric melting zone (110) and / or flame melting zone (120), respectively, and / or based on the composition of the glass to be produced, or even based on the cullet content of the vitrifiable mixture.

24. The melting furnace according to any one of claims 1 to 23, characterized in that The first convection circuit (210) and the second convection circuit (220) are separated by a temperature inversion zone (230) of the circuits (210, 220), the temperature inversion zone being determined by a hot spot or heat source corresponding to the hottest point of the glass, and the clarification zone (200) comprises at least one burner (215) arranged to obtain the hot spot defining the temperature inversion zone (230) of the circuits, wherein a ridge (260) is arranged.

25. The melting furnace according to any one of claims 1 to 24, characterized in that The regulating tank kiln (310) of the cooling zone (300) includes a neck (320) followed by a working end (330) from upstream to downstream.

26. A method for producing glass, in particular for supplying a unit for floating glass on a bath of molten metal, the method being implemented in a hybrid melting furnace (10) according to any one of the preceding claims, characterized in that The method comprises at least one melting step carried out in the hybrid melting furnace (10), the melting step being operated according to an operating mode of the melting furnace, the operating mode being selected from: - a first electromelting operation mode, in which molten glass is produced only by the at least one electromelting zone (110); - a second hybrid operating mode, wherein molten glass is produced jointly by the at least one electric melting zone (110) and the flame melting zone (120); - a third flame-melting operating mode, wherein molten glass is produced only by the at least one flame-melting zone (120).

27. The method for manufacturing glass according to claim 26, characterized in that: Prior to carrying out the melting step in the melting furnace, the method comprises a determination step of selecting one of the operating modes based on at least one selection parameter, the at least one selection parameter comprising: - economic criteria, which are based on the respective costs of electrical energy and fuel for further melting of the vitrifiable mixture; - ecological criteria based on the carbon footprint (CO2) associated with electricity and said fuels respectively, and - at least one technical criterion based on the draw volume to be produced in relation to the amount of molten glass obtainable by the at least one electric melting zone (110) and / or flame melting zone (120), and / or based on the composition of the glass to be produced, or even based on the cullet content of the vitrifiable mixture.

28. The method for producing glass according to claim 27, characterized in that Said step of determining the operating mode of the hybrid melting furnace (10) is performed by a control unit (UC) which is associated with the hybrid melting furnace (10) so that the hybrid melting furnace can be controlled.

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