Glass melting process with very low to zero CO2 emissions

Abstract

The present invention relates to a method for melting a vitrifiable material to produce a sheet glass, the method comprising the steps of: (i) providing a furnace having a specific design; (ii) charging a vitrifiable material into a primary melting tank and / or into an auxiliary melting tank having at least one inlet device, the vitrifiable material comprising a raw material and cullet in an amount of at least 10% by weight of the total amount of the vitrifiable material; (iii) pre-melting at least a portion of the cullet in the auxiliary melting tank and flowing the pre-melted cullet to the main melting tank; (iv) melting the vitrifiable material in the main melting tank; (v) clarifying the melt in the clarification tank by heating with an oxycombustion heating device supplied with a gas and / or hydrogen; (vi) flowing the melt from the clarification tank to a working zone through an outlet device; (vii) capturing CO2 from a flue gas, the flue gas having a CO2 concentration of at least 35%; the electrical input fraction ranges from 30% to 85%, and the step of capturing CO2 comprises a compression and / or dehydration step.

Description

Technical field

[0001] The present invention relates to a glass melting method which aims to continuously supply molten glass to a flat glass forming facility (such as a float or rolling facility). In particular, the present invention relates to a glass melting process which provides many advantages, especially in CO 2 In particular, CO 2 Emissions and capture aspects.

[0002] The invention relates more particularly, but not limited to, to melting methods for flat glass, involving large-scale production capacity (ie, up to 1000 tons / day or more). Background technology

[0003] Global warming and CO reduction 2 Emission requirements increase pressure on glass manufacturers, and increase energy prices and CO 2 Taxes, which may soon seriously threaten the competitiveness of the glass industry.

[0004] Against the backdrop of urgent action to reduce carbon emissions, the glass industry has invested a lot over the years in decarbonizing its manufacturing processes in order to produce glass commodities suitable for sustainable, resource-efficient, and low-carbon societies.

[0005] To achieve transformation, the glass industry has identified many solutions / technology to approach this ambitious goal, such as, for example, using electricity as energy, using such as H 2 Or alternative and more environmentally friendly energy for biogas, use of alternative raw materials, increase the use of broken glass as raw materials, heat recovery, CO 2 Capture, utilize and store (or CCUS),…

[0006] However, all of these technologies are accompanied by serious shortcomings or problems in actual implementation, or are not feasible from an economic point of view. Therefore, there is still a need for a glass melting method that allows for a substantial reduction in CO 2 but at the same time keeping glass manufacturers economically acceptable.

[0007] Regarding the use of electricity as energy:

[0008] Furnaces known to use electrically molten glass raw materials show CO 2 Reduced emissions and showed a reduction in total energy consumption. Glass melting furnaces with heating power supplied entirely by electricity are known and have been developed, although they have been well proven to be applicable only for small-scale capabilities, i.e., below 300 tons / day (scale expansion to more than 600 tons / day). To be developed).

[0009] In contrast to classic combustion furnaces called "hot top furnaces" (or "temperature top furnaces"), these furnaces are also called "cold top furnaces" because raw materials are distributed over the melting surface of the glass to form an insulating mix. "Thin layer" causes the temperature to drop from about 1400°C in the glass melt to less than 500°C (possibly to 50°C) at the thin layer and above. An all-electric furnace provides significant advantages. First, direct CO of all-electric furnace 2 Emission, heat NO x Or SO x Emissions are very low.

[0010] Furthermore, since the melting energy is generally transferred into the glass (eg, since the electrode allows current to pass through and heat the melted glass from its volume), the heat loss in the all-electric furnace is much lower, which makes the entirety of the entirety of the furnace. Electric furnaces are energy-saving furnaces, for example, compared with hot-top combustion furnaces. In hot-top combustion furnaces, even if a heat recovery system is used, significant heat loss will occur in the superstructure of the furnace and the residual exhaust gas. Unfortunately, all-electric furnaces also show some disadvantages compared to combustion hot top furnaces. In particular, in such furnaces: -Glass quality does not meet the typical flat glass specifications, especially in terms of small bubble density; and - The temperature at the bottom where the electrode is located is very high (for example greater than 1400°C), which can lead to significantly shortening the furnace life (typically shortening from the life of more than 15 years of conventional furnaces to not By 8 years, sometimes even shortened to 2 to 7 years).

[0011] In addition, the surface melting rate of the cold-top all-electric furnace, i.e. the amount of glass melted from the raw material per unit time and per unit unit furnace area (at T / d / m) 2 ) is a direct function of glass temperature. To achieve an acceptable surface melting rate of such furnaces (approximately 2T / d / m 2 To 3T / d / m 2 ), it is necessary to set the glass temperature to be above 1400°C, or even above 1450°C, which will further adversely affect the furnace life. In contrast, the surface melting rate of a classic combustion furnace is typically about 5 T / d / m 2 . Alternatively, if the lower surface melting rate is targeted to avoid affecting the furnace life as much as possible, it would mean that the melting area needs to be significantly increased, thus having a significant negative impact on the required investment and the industrial space occupied. .

[0012] Finally, this cold top furnace lacks flexibility in energy (electricity only).

[0013] It is also known to combine combustion heating devices and electrical heating devices in a "hybrid system". In this configuration that mainly uses a "hot top" operation, the furnace includes a burner and powered electrodes.

[0014] This hybrid furnace has great advantages in energy flexibility and allows adjustment of the electrical input fraction according to different parameters (operating parameters or speculative parameters).

[0015] Furthermore, the hot top furnace allows a higher surface melting rate for the same bottom temperature than the cold top furnace (or alternatively, the bottom temperature for the same surface melting rate is lower).

[0016] In addition, hybrid furnaces with "hot top" operation show some disadvantages. In particular, significant heat loss occurs at the furnace top and walls of the melting zone and (ii) the hot exhaust gas / flue gas generated during melting, thereby reducing the energy efficiency of the furnace. It is possible to consider using a heat recovery system to limit heat loss with the flue gas, but this does not completely solve the problem and requires a specific investment.

[0017] Furthermore, in such furnaces, the temperature of the furnace top / super structure in the melting zone may become very low under some conditions (eg less than 1000°C), which can lead to alkaline condensation in the zone (eg NaOH, for example, NaOH) ) has a significant increase in risk, resulting in corrosion of refractory materials on the furnace roof.

[0018] In addition, in these furnaces, especially due to the limitations described above for all-electric furnaces (ie, bottom and top corrosion phenomena), the electrical input fraction is generally limited to a maximum of 35% of the total energy input.

[0019] Recently, some hybrid furnaces have been described as having specific designs to increase electrical input fractions (eg up to 80%), but for most of these hybrid furnaces they use cold top operations and bring some problems. About the use of hydrogen gas H 2 Or alternative and more environmentally friendly energy for biogas:

[0020] Even though it's obvious they will be in the environment / energy / CO 2 Emissions bring advantages, but severe restrictions also hinder their widespread use in the glass industry (lack of biogas availability, and H 2 The price is expensive (which makes H so far 2 As the only energy source for molten glass raw materials is economically infeasible solution)).

[0021] About Heat Recovery:

[0022] Recovering waste heat from flue gas has been widely used in the glass industry to preheat combustion air entering the furnace at temperatures above 1000°C, or to preheat gas at temperatures above 400°C and 500°C respectively Oxygen ("Hotox"). In addition, waste heat from flue gas can also be used to preheat vitrified materials, especially broken glass. However, it is known that preheating raw materials / broken glass cannot be combined with electrical melting, because the temperature of the flue gas released from the raw material is too low in this case.

[0023] About using CO 2 capture:

[0024] Typically, CO in industrial processes / equipment 2 The capture process consists of two steps: (i) separation of CO from the exhaust gas mixture by selective reaction with the separating material 2 ("Absorb" CO 2 ) and (ii) regeneration of the used material by reverse reaction ("desorption" CO 2 ). The separation material can be reused for CO by repeating steps (i) and (ii) in sequence 2 capture. The amine in the form of a solvent or membrane or porous adsorbent is CO in the industry so far 2 The most widely used materials during the capture process, as the technology is mature and can effectively isolate amines and CO through reversible reactions 2 . However, such amine methods (eg, using aqueous MEAs) are still a poor choice, especially in the specific context of the glass industry to date, which is at least due to the following main reasons: -In known glass manufacturing methods, combustion gas / flue gas exhibits low concentrations of CO 2 (Generally, less than 30% by volume and usually about 10% to 20%), and due to the presence of many other components (mainly N 2 , H 2 O, O 2 , NO x , SO x ), low purity, thus greatly affecting CO 2 the efficiency of the capture process; and -amine-CO 2 The capture process requires a large amount of energy to regenerate the amine adsorbent (desorption process), which affects the total energy consumption (and potentially CO depending on the energy used. 2 emissions, which is obviously counterproductive under the current circumstances).

[0025] Furthermore, known glass manufacturing methods produce very high flue gas volume or flow rates, regardless of the method used, when trying to capture CO from those flue gases 2 This also directly affects investment and operational costs. Purpose of invention

[0026] It is an object of the present invention to overcome the disadvantages described above with respect to the prior art and to solve the technical problems, namely, by providing a glass melting method for producing flat glass using combustion heating devices and electrical heating devices, in accordance with a classic melting furnace This glass melting method exhibits reduced overall energy consumption and reduced CO, especially compared with classic "hot top" hybrid melting furnaces 2 emission.

[0027] It is another object of the present invention to provide a glass melting method that uses combustion heating devices and electrical heating devices to produce flat glass and displays an acceptable surface melting rate (especially higher than 2T / d / m 2 , or better higher than 3T / d / m 2 surface melting rate).

[0028] Another object of the present invention is to provide a glass melting method for producing flat glass that uses combustion heating devices and electrical heating devices and extends life compared to classic hot top mixed melting furnaces.

[0029] It is another object of the present invention to provide a glass melting method for producing flat glass using combustion heating devices and electric heating devices, which allows for simple and cost-effective CO 2 capture.

[0030] Another object of the present invention is to provide a glass melting method for producing flat glass using combustion heating devices and electrical heating devices, which is economically feasible. Contents of invention

[0031] The present invention relates to a method for melting a vitrified material to produce flat glass, the method comprising the following steps: - Provides a furnace, which includes: (i) a main melting tank M, the main melting tank includes at least one upstream area Z1 covered by the furnace top C1 and equipped with an electric heating device, a downstream area Z2 covered by the furnace top C2 and equipped with a combustion heating device, and a furnace The transition zone T between the top C1 and the furnace top C2; (ii) Auxiliary melting tank; (iii) a clarification tank F, which is covered by the furnace top C4 and equipped with an oxygen combustion heating device; (iv) A neck-shaped portion N, which is covered by the furnace top C3 and separates the main melting tank M and the clarification tank F; (v) at least one inlet device X located at the main melting tank M; (vi) the outlet device O located downstream of the clarification tank F; and (vii) at least one flue gas extraction device located at at least one upstream area Z1; The height H1 of the furnace top C1 of the furnace is defined by: H1≤0.75*H2; H2 is the height of the furnace top C2, and the length L1 of at least one upstream area Z1 is defined by: 0.25*(L1+L2)≤L1≤ 0.8*(L1+L2); L2 is the length of the downstream region Z2, and the length LT of the transition region T is defined by: LT≤0.2*(L1+L2), - Fill the vitrified material into the main melting tank M with at least one inlet device X, which comprises the raw material and broken glass, in the amount of the total vitrified material of the vitrified material. at least 10% by weight of the amount; - Pre-melting at least a portion of the broken glass in the auxiliary melting tank and causing the pre-melting broken glass to flow to the main melting tank; -Fusing vitrified material in the main melting tank M with a heating device; - The melt in the clarification tank F is clarified by heating with an oxygen combustion heating device, which is supplied with gas and / or hydrogen; - Flow the melt through the outlet device O from the clarification tank F to the working area; -Catch CO from flue gas 2 , the flue gas has at least 35% CO 2 concentration; where the electrical input fraction ranges from 30% to 85%, and where CO is captured from the flue gas 2 The steps include compression and / or dehydration steps.

[0032] Therefore, the invention is based on a novel and creative method. In particular, the inventors have discovered that in the glass melting method of producing flat glass, by combining: -Use a furnace with a specific design, which includes the following combinations: (i) separate the "mixed" melt tank and the combustion clarification by neck, and (ii) segment the melt tank into different furnace top heights two zones (thus providing a cooler upstream and a warmer downstream with significant temperature differences), -Use oxygen as a combustion aid -Use gas and / or hydrogen as combustible substances, - Use the smallest amount of broken glass in vitrified materials, -The step of using pre-melting at least a portion of the broken glass, and -Use specific and high electrical input scores, Can be obtained at the same time: -Acceptable surface melting rate, -Extended furnace life, - Significant reduction in total energy consumption; -CO 2 Significant decrease in total output; - Flue gas from decomposition of raw materials (less NOx and SOx impurities) and flue gas from combustion can be independently extracted, thereby allowing separation and proper treatment of each flue gas if required; and - Significant reduction in flue gas volume and CO in the flue gas 2 Significant increase in concentration and its purity allows for the use of simple, efficient and cost-effective CO 2 Capture process.

[0033] By carrying out all features of the invention, the method of the invention exhibits very low CO 2 fingerprints, and economically feasible.

[0034] In this specification and claims, it will be well understood by those skilled in the art that, as used herein, the term "a / an" or "the" means "at least, unless expressly indicated to the contrary, unless otherwise specified. One / type” and should not be limited to “only one / type”. Furthermore, when the range is indicated, the endpoint is included. Furthermore, all integer values ​​and subdomain values ​​within the numerical range are clearly included as if they were explicitly written. Finally, the terms "upstream" and "downstream" refer to the direction of flow of glass and should be understood in its usual sense, i.e., from the inlet(s) along the average direction of movement of the vitrified material / glass melt. to outlet device(s). The expression "upstream part" is understood to mean the upstream part of the first third of the length positioned along the horizontal and longitudinal axis of the furnace. The expression "downstream part" is understood to mean the downstream part of the last third of the length.

[0035] Other features and advantages of the invention will become clearer from reading the following description of the preferred embodiments and the accompanying drawings given by simple illustrative and non-limiting examples.

[0036] Figure 1 It is a flowchart of an embodiment of the method of the present invention.

[0037] Figure 2 It is a schematic plan view (vertical cross-section) of an embodiment of the furnace of the present invention.

[0038] Figure 3 It is a schematic plan view (horizontal cross-section) of an embodiment of the furnace of the present invention.

[0039] Figure 4 It is a schematic plan view (horizontal cross-section) of an embodiment of the furnace of the present invention.

[0040] Figure 5 It is a schematic plan view (horizontal cross-section) of an embodiment of the furnace of the present invention.

[0041] According to the invention and Figure 1 As shown, the method for melting a vitrified material to produce flat glass includes the first step of providing a specific furnace, the furnace 1 including: (i) a main melting tank M, the main melting tank includes at least one upstream area Z1 covered by the furnace top C1 and equipped with an electric heating device, a downstream area Z2 covered by the furnace top C2 and equipped with a combustion heating device, and a furnace The transition zone T between the top C1 and the furnace top C2; (ii) Auxiliary melting tank; (iii) a clarification tank F, which is covered by the furnace top C4 and equipped with an oxygen combustion heating device; (iv) A neck-shaped portion N, which is covered by the furnace top C3 and separates the main melting tank M and the clarification tank F; (v) at least one inlet device X located at the main melting tank M; (vi) the outlet device O located downstream of the clarification tank F; and (vii) at least one flue gas extraction device located at at least one upstream area Z1; The height H1 of the furnace top C1 of the furnace is defined by: H1≤0.75*H2; H2 is the height of the furnace top C2, and the length L1 of at least one upstream area Z1 is defined by: 0.25*(L1+L2)≤L1≤ 0.8*(L1+L2); L2 is the length of the downstream region Z2, and the length LT of the transition region T is defined by: LT≤0.2*(L1+L2),

[0042] According to the invention and as commonly used in the field of glass, "melting tank" refers to a tank that defines a region where vitrified material (raw material and / or broken glass) is fed and is heated and when the furnace is in processing When the tank comprises a "thin layer" of melt and unmelted vitrified material, the thin layer floating on the melt and gradually melts, and thus decreases from upstream to downstream of the melt tank.

[0043] According to the invention and as commonly used in the glass field, a "clearing tank" refers to a tank that defines a region in which there is no longer a "thin layer of unmelted vitrified material floating on the melt" ", the glass melt is heated at a temperature above the melt tank temperature (usually above 1400°C, or even above 1450°C) in order to refine the glass (mainly by eliminating most of the air bubbles). Such clarification tanks are also commonly referred to in the art as "purification tanks".

[0044] According to the present invention, the "neck-like portion" that separates the main melting tank and the clarification tank refers to the width and (top) height compared to the downstream region of the melting tank (z2) and compared to the upstream region of the clarification tank F and in the width and (top) height compared to the upstream region of the clarification tank F and the height of the (top) compared to the width and furnace top) height compared to the downstream region of the clarification tank F and the height of the (top) compared to the downstream region of the clarification tank F and the height of the (top) compared to the upstream region of the clarification tank F. Upward narrowing. The opening of the neck-shaped portion according to the invention is only partially below the free surface of the glass melt / thin layer, and a free opening is left above the glass melt / thin layer.

[0045] This furnace design with segmentation of the melting tank and the clarification tank and the height segmentation of the melting furnace top brings many advantages, which is beneficial to energy consumption / CO 2 Emission and facilitates the mechanical stability / life of the furnace.

[0046] Specifically, by combining the following two points in a specific design, i.e., (i) separate the main melt tank and the clarification tank through the neck and (ii) segment the main melt tank into two having different top heights. (and thus provide a cooler upstream and warmer downstream with significant temperature differences), the overall energy consumption of the furnace can be significantly reduced while maintaining a high electrical input fraction (and thus reducing CO 2 ), maintain an acceptable surface melting rate, and improve the mechanical stability and life of the furnace.

[0047] The melting furnace tops C1 and C2 in the present invention are specifically designed to take advantage of the advantages of both the "cold top" and the "hot top" zone and from the relatively low temperature upstream (below 1100°C) to the relatively temperature relative to the temperature High downstream (above 1300°C) creates a temperature gradient.

[0048] In particular, the furnace of the present invention allows for complete control of (i) the temperature in each zone and (ii) the flue gas redistribution between the two zones of the main melt tank and between the main melt tank and the clarification tank / Extraction to optimize energy consumption, avoid alkali corrosion as much as possible, and also optimize CO 2 capture.

[0049] Furthermore, the furnace of the present invention is conducive to creating a strong temperature difference between the upstream and downstream portions of the main melting tank while avoiding the return of the flue gas from the clarification tank toward the melting tank as much as possible.

[0050] From an energy efficiency perspective, the furnace of the present invention is advantageous because it allows: -Segmenting the atmosphere and cutting off the heat radiation from the clarification tank toward the main melt tank in order to effectively limit the energy in the zone where high temperatures are required; and - Pumping flue gas from the upstream portion / outlet at the lowest possible temperature to limit useless heating of gases released from the vitrified material and to optionally maximize the vitrified material and glass from the combustion gases to the vitrified material and glass Heat transfer of the melt.

[0051] From the perspective of surface melting rate, the furnace of the present invention is advantageous because it allows relatively high temperatures (greater than 1300°C) to be achieved in the downstream portion of the melting tank in order to improve the melting kinetics of the vitrified material.

[0052] From a corrosion perspective, the furnace of the present invention is advantageous because it allows: - Separating the atmosphere between the main melt tank and the clarification tank allows limiting / avoiding the return of flue gases from the clarification zones, which are highly corrosive due to the high temperature required for clarification; as well as - Having a limit on the overall flow rate of the molten glass, which will advantageously reduce the strength of the glass convection in the molten tank and reduce the glass speed, thereby reducing wear and corrosion of the bottom refractory material.

[0053] Finally, the furnace of the present invention also allows the furnace of the main melting tank and the clearing tank to be sized (length, width and furnace top height) and fire resistant The material properties are completely unconnected, so each slot is optimized with energy efficiency, glass quality, equipment space limitations and mechanical / structural / other limitations.

[0054] Figure 2 and Figure 3 An embodiment of the furnace 1 of the present invention is shown ( Figure 2 : Vertical cross section, Figure 3 : Horizontal cross-section).

[0055] The furnace 1 of the present invention includes a main melting tank M, a neck-shaped portion N and a clarification tank F. The components of M, N and F are usually made of refractory materials that are resistant to high temperature, smoke corrosion and erosion of molten materials. Illustrative glass melt level in the tank (excluding the thin layer of the compound material) is Figure 2 The dotted lines in the are shown.

[0056] According to the invention and Figures 2 to 3 As shown, the furnace 1 includes at least one inlet device X at the main melting tank M to fill the furnace with vitrified material (glass raw material and / or broken glass).

[0057] In order to improve the distribution over the surface of the main melting tank M, several inlet devices, i.e. two or three inlet devices, are advantageously provided, upstream of the main melting tank M (or in other words, in zone Z1). Preferably, and as known in the art, at least one inlet device X is located upstream of the groove over the width of the main melting groove M and / or laterally over the length of the main melting groove.

[0058] like Figures 2 to 3 As shown, the furnace 1 of the present invention comprises a main melting tank M and an auxiliary melting tank (not shown in the figure), which comprises: - At least one upstream region Z1 covered by furnace top C1 and including electric heating device 2; - The downstream area Z2 covered by the furnace top C2 and includes an electric heating device 2 and a combustion heating device 3; - Transition zone T between furnace top C1 and furnace top C2.

[0059] According to an advantageous embodiment, the downstream zone Z2 comprises an additional electrical heating device, such as Figure 2 and Figure 3 Shown.

[0060] The electric heating device 2 according to the invention is preferably located at the bottom of the main melting tank M and is also preferably formed of an immersion electrode. The electrodes are advantageously arranged in a grid pattern (chessboard) multiples of 3 or 2 in order to facilitate connection with the transformer and current balance. For example, the number of electrodes is designed to limit the maximum power of each electrode to 200 kW while maintaining the maximum current density at the electrode surface to 1.5 A / cm 2 . Furthermore, for example, the immersion electrode height is between 0.3 and 0.8 times the height of the glass melt.

[0061] The combustion heating device 3 in the downstream region Z2 in the main melting tank M is composed of a burner in particular. Specifically, these burners may be generally arranged in rows and along side walls of the zone, for example on one side or alternatively on each side thereof, so that the flame may spread almost the entirety of the zone. Above the width. Alternatively or additionally, these burners may also be located in the furnace top C2, which promotes heat transfer to the mixing material, thereby facilitating the mixing material length and preventing the mixing material from reaching the end of the downstream zone Z2, This avoids reaching the downstream end of the main melting tank.

[0062] Fuel and air, or fuel and oxygen, or fuel and oxygen-rich gas may be supplied to the combustion heating device 3 . The fuel can be fossil fuel, natural gas, biogas, hydrogen, ammonia, synthesis gas, or mixtures thereof.

[0063] According to an advantageous embodiment, at least one upstream zone Z1 may include additional auxiliary combustion heating means (eg, burner, not shown in the figure) in order to allow the control of the temperature of the furnace top C1 (eg, limiting temperature variations along zone Z1) , and raise the temperature when the temperature of the furnace top drops below a certain level (eg, below 600°C). In particular, these auxiliary combustion heating devices can advantageously be located in the furnace top C1 to reduce space occupancy in the free volume above the melt / mixture thin layer.

[0064] According to an embodiment, the auxiliary melting tank (not shown in the figure) is preferably connected at the upstream portion of the main melting tank M (eg, in zone Z1), more preferably as far as possible upstream of the main melting tank M (in particular, In zone Z1) in order to achieve better uniformity / mixture of the pre-melt and the melt.

[0065] An example of an auxiliary melting tank suitable for use in the present invention is described in Patent Application EP 2137115A1.

[0066] The upstream region Z1 according to the invention has a furnace top C1. The downstream region Z2 according to the invention has a furnace top C2.

[0067] According to the present invention, the height H1 of the furnace top C1 is defined by: H1≤0.75*H2; H2 is the height of the furnace top C2. In the present invention, the change in the height of the furnace top C1 and the furnace top C2 along the main melting tank M means a transition zone T.

[0068] The "height" of the furnace roof in the present invention refers to the "height" of the furnace roof from the inner surface of the furnace roof to the glass melt (if there is a thin layer of compounding material, the thin layer of compounding material is excluded) The average inner height (e.g. Figure 2 as shown). The height H1 of the furnace top C1 may be substantially constant along the length of the furnace top, or alternatively, the height may vary over the length of the furnace top. The height H1 of the furnace top C1 may be substantially constant along the width of the furnace top, or alternatively, the height may vary over the width of the furnace top (eg, in the case of an arch / doubled furnace top Down). The height H2 of the furnace top C2 may be substantially constant along the length of the furnace top, or alternatively, the height may vary over the length of the furnace top. The height H2 of the furnace top C2 may be substantially constant along the width of the furnace top, or alternatively, the height may vary over the width of the furnace top (eg, in the case of an arch / doubled furnace top Down).

[0069] According to an embodiment of the present invention, the height H1 of the furnace top C1 is defined by: H1≤0.7*H2, preferably H1≤0.6*H2, and even H1≤0.5*H2. This allows for the above advantages of the present invention to be enhanced.

[0070] According to the present invention, the length L1 of at least one upstream region Z1 is defined by: 0.25*(L1+L2)≤L1≤0.8*(L1+L2); L2 is the length of the downstream region Z2.

[0071] "Length" refers to dimensions taken along the glass stream as herein and throughout the specification and claims.

[0072] According to another embodiment of the invention, the length L1 of at least one upstream region Z1 is defined by: 0.3*(L1+L2)≤L1, preferably 0.4*(L1+L2)≤L1, even 0.5*(L1+L2)≤L1, or even 0.5*(L1+L2)≤L2 )≤L1. This also allows for the above advantages of the present invention to be enhanced.

[0073] According to another embodiment of the invention, the length L1 of at least one upstream region Z1 is defined by: L1≤0.75*(L1+L2), preferably L1≤0.7*(L1+L2).

[0074] It is worth mentioning that the total length of the main melting tank M may be slightly higher than the sum of (L1+L2) (for example, about 10% to 15% higher). In fact, it is common in the art to provide a first zone Z0 (usually referred to as "the first zone Z0 for introducing the vitrified material in the direction of the melt) for the introduction of the vitrified material (usually referred to as " feeding room”) (not shown in the figure).

[0075] The furnace roof C1 according to the invention may be arched or dome-shaped, or alternatively, the furnace roof may be flat. Independently with the furnace roof C1, the furnace roof C2 according to the invention may be arched or dome-shaped, or alternatively, the furnace roof may be flat.

[0076] Advantageously, the furnace top C1 can be composed of a refractory material generally made of silica (eg, high purity silica). Silica refractory materials are known to be more sensitive to corrosion (for example compared to alumina), but because of the presence of a neck-shaped portion that separates the melting tank from the clarification tank in the present invention, the alkali in the flue gas present in the main melting tank is more few.

[0077] The advantage of silica is its low coefficient of expansion at temperatures above about 600°C, which allows to withstand high changes in temperature without disturbing the furnace top upper structure.

[0078] Alternatively, the furnace top C1 and / or the furnace top C2 may be composed of refractory materials generally made of alumina or AZS (alumina-zirconia-silica) which have better corrosion resistance. And therefore has a better life span.

[0079] According to the invention and Figure 2 As shown, the furnace comprises a main melt tank M, which comprises at least one upstream region Z1 and a downstream region Z2 having different furnace top heights, the furnace top C1 has a height H1 and the furnace top C2 has a height H2.

[0080] In the furnace provided in the method according to the invention, the change in the height of the furnace top C1 and the furnace top C2 along the main melting tank M means a transition zone T.

[0081] According to the invention, the length LT of the transition zone T is defined by: LT≤0.2*(L1+L2), preferably LT≤0.15*(L1+L2), or even LT≤0.1*(L1+L2).

[0082] According to an embodiment, the transition zone T between the furnace top C1 and the furnace top C2 may be an end wall. The end wall according to the embodiment may be a vertical wall or a short inclined wall (allowing a progressive transition). In this embodiment, the furnace top C1 preferably has an inner surface which is generally at the same level as the lower edge of the end wall or is slightly lower than the lower edge. The end wall may be composed of a suspended rear wall. The suspended rear wall according to the invention may be, for example, the suspended rear wall described in Patent Application US 5011402 A. Alternatively, the end wall may be located on the outer surface of the furnace top C1.

[0083] According to another embodiment, the transition zone T between the furnace top C1 and the furnace top C2 is a shielding wall. The "blocking wall" in the present invention means that the lower edge extends below the inner surface of the furnace top C1 and thus closer to the wall of the glass melt, but the wall leaves free space above the glass melt. The advantage of this embodiment is to further reduce the radiant heat exchange between the upstream and downstream regions of the main melting tank and to better separate the flue gas released from Z1 and Z2 while allowing the release of glassable from upstream Free space through which the material passes. For example, as known in the art, the shielding wall may be an air-cooled suspension wall. The shielding wall according to the invention may be formed of a suspended U-shaped shielding wall (as described for example in Patent Application US 3399046 A).

[0084] According to another embodiment, the transition zone T between the furnace top C1 and the furnace top C2 includes at least one step. In a configuration with one step, the height change of the furnace top C1 and the furnace top C2 is obtained by a transition zone T, which from C1 to C2 includes: a first end wall, a short height between H1 and H2 the furnace top and the second end wall. The advantage of this configuration is that it facilitates the production of the transition between the furnace roof C1 and the furnace roof C2 and increases the transition stability.

[0085] "Length of the transition zone" refers to the dimensions of the zone along the glass flow, as used herein and throughout the specification and claims, including walls(s) even on the furnace top C1 and / or furnace thickness on and / or overlap with top C1).

[0086] According to an advantageous embodiment, the transition zone is composed of a refractory material generally made of silica.

[0087] Advantageously, according to another embodiment, the furnace top C1 and the transition zone T are made of the same refractory material in order to avoid expansion between materials and / or corrosion between materials. Preferably, they are composed of a refractory material made generally of silica.

[0088] Also advantageously, according to another embodiment, the furnace top C1, the furnace top C2 and the transition zone T are made of the same refractory material in order to avoid expansion between materials and / or corrosion between materials. Preferably, they are composed of a refractory material made generally of silica.

[0089] According to the invention, the furnace comprises a clarification tank F, which is covered by the furnace top C4 and is equipped with an oxygen combustion heating device 3'.

[0090] "Oxygen combustion device" 3' according to the present invention means supplying gaseous oxygen (O) 2 ) The combustion device as a combustion aid. Typically, O supplied to a glass melting furnace 2 The gas combustion aid is at least 90% purity, or even at least 95% purity. Compared with the use of air, the advantage of using gaseous oxygen as a combustion aid is that it greatly reduces the so-called corrosive <<NOx" pollutants that appear during combustion. Even if they can still be present in the flue gas (depending on O 2 The purity and amount of parasitic air will also be very low.

[0091] The oxygen combustion heating device 3' in the clarification tank F according to the invention can be formed by burners advantageously arranged along the side walls of the clarification tank. Furthermore, the burners are advantageously spaced from each other so as to distribute the energy supply over a portion of the clarification tank F, preferably upstream portion (eg, over about 50% of the length). These burners are also usually arranged in rows on one side of the clarification groove F, or alternatively on each side of the clarification groove, and are preferably arranged in an interlaced manner (to spread the flame to almost the entire width of the groove). superior).

[0092] The furnace top C4 according to the invention is preferably arched or dome-shaped.

[0093] According to an advantageous embodiment, the clarification tank F may include additional electrical heating means (not shown in the figure), especially in the upstream portion of the clarification tank (eg, at about 50% of its length) including additional electrical Heating device. This allows for increased electrical input fraction and therefore increased energy efficiency, thereby reducing CO 2 emission.

[0094] According to the invention, the furnace comprises a neck-shaped portion N, which is covered by the furnace top C3 and separates / sections the main melting tank M from the clarification tank F.

[0095] According to the present invention, the "neck-shaped portion" that separates the main melting tank M and the clarification tank F refers to the width and (furnace) compared with the downstream region of the main melting tank (z2) and compared with the upstream region of the clarification tank F and (furnace) in width and (furnace) in comparison with the downstream region of the main melting tank F and (dryer) in width and (dryer) in furnace compared with the downstream region of the main melting tank F and (dryer) in width and (dryer) in furnace compared with the downstream region of the clarification tank F and (dryer) in furnace and (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in furnace (dryer) in Top) becomes narrower in height. The opening of the neck-shaped portion according to the invention is only partially below the free surface of the glass melt / mixture thin layer, and a free opening is left above the glass melt / mixture thin layer.

[0096] Based on the definition of the neck-shaped portion according to the present invention, the width W of the neck-shaped portion N N As follows: W N <W M ,W M It is the width of the main melting tank M. Also based on the definition of the neck-shaped part according to the invention, the width W of the neck-shaped part N N As follows: W N <W F ,W F It is the width of the clarification groove F.

[0097] "Width" in the present invention refers to the (average) dimensions perpendicular to the glass flow throughout the specification and claims.

[0098] This furnace design with segmented furnaces for melting and clarification tanks brings many advantages, which is beneficial to energy consumption / CO 2 Emission and facilitates the mechanical stability / life of the furnace. In particular, advantageously, in the context of the invention, the furnace with its specific segment design, if desired, allows independent treatment of the flue gas from the main melt tank M (zone Z1 and / or zone Z2) and from The flue gas of the clarification tank.

[0099] The base of the neck-shaped portion N in the present invention may be located substantially at or above or below the bottom of the base plate / bottom of the main melting tank M. Furthermore, the base of the neck-shaped portion N may be located substantially at or above or below the bottom of the bottom plate / bottom of the clarification groove F.

[0100] According to an embodiment, the neck N does not include any heating means, such as any electrical heating means.

[0101] The furnace roof C3 according to the invention may be arched or dome-shaped, or alternatively, the furnace roof may be flat. Based on the definition of the neck-shaped portion according to the present invention, the height H3 of the furnace top C3 of the neck-shaped portion N is lower than the height H2 of the furnace top C2 of the main melting tank M. Also based on the definition of the neck-shaped portion according to the invention, the height H3 of the furnace top C3 of the neck-shaped portion N is lower than the height H4 of the furnace top H4 of the clarification tank F.

[0102] According to a further advantageous embodiment of the invention, the furnace may include a removable wall (eg, a scraper rod from the side wall of the neck) located at the neck so that (i) may prevent possible arrival of the main The unmelted vitrified material at the end of the melting tank prevents the unmelted vitrified material from passing through the neck toward the clarification tank and (ii) controls the reverse direction of the glass melt from the clarification toward the main melting tank The strength of the flow or eliminates the reverse flow of the glass melt from clarification towards the main melt tank.

[0103] According to yet another advantageous embodiment of the invention, the furnace may include a removable wall located at the neck (eg, a shielding wall passing through the furnace top) in order to increase the melting tank and the clarification tank in the atmosphere and thermal radiation segmentation.

[0104] According to the invention, the furnace comprises an outlet device O, which is located downstream of the clarification tank F for causing the molten glass to reach the working area. According to an embodiment, the outlet device O is usually formed of a neck-like portion to direct the melt to the working area, which is generally referred to as the "working end" or also as the "pressure steaming" or also as the "regulating area". Alternatively, the outlet device O is formed of a throat-like portion (ie, an opening completely immersed in the glass melt with no free surface left above) in order to direct the melt to a working area including, for example, for the fork furnace(s) . The working area according to the invention may include, for example, a regulating zone in which the glass melt is thermally adjusted by controlled cooling before leaving the zone through the outlet to reach the molding zone. Such forming zones may include, for example, float facilities and / or rolling facilities.

[0105] According to the invention (such as Figure 2 and Figure 3 As shown), the furnace comprises at least one flue gas extraction device 4 located at at least one upstream region Z1, preferably close to the inlet device(s) X, in order to recover heat from the flue gas Heat is transferred to the glass melt and / or the unmelted vitrified material in the main melting tank M.

[0106] According to an embodiment of the invention, the furnace further comprises at least one flue gas extraction device in the downstream zone Z2 and / or at least one flue gas extraction device in the clarification tank F (not shown in the figure).

[0107] When the extraction device is present in zone Z2, if the flue gas in downstream zone Z2 is rich in alkali, this advantageously allows the flue gas to be extracted from the downstream zone (to avoid condensation in zone Z1 and the consequent corrosion).

[0108] When the extraction device is present in the clarification tank F, the extraction device is preferably located in the upstream portion of the clarification tank.

[0109] Preferably, in the present invention, the extraction device(s) 4 are located on the side walls (side walls on one or both sides).

[0110] In particular, it is advantageous in the present invention to maximize the extraction of flue gas from upstream of the furnace, especially from upstream of the main melting tank. For example, at least 25% of the flue gas generated in the melting zone can advantageously be extracted from upstream of the main melting tank. However, it may be advantageous to extract a portion of the flue gas from downstream in the main melting tank in order to limit the risks associated with alkali erosion of the furnace top refractory material. In fact, alkali evaporation increases with temperature, so the alkali concentration in the flue gas in the downstream portion of the melting zone will be higher. Flue gas with higher alkali concentrations may create condensation-related problems in the cooler areas of the superstructure / top, so it is more appropriate to discharge the flue gas from the downstream. Furthermore, it may be advantageous to extract a portion of the flue gas from upstream in the main melting tank because in this upstream region the flue gas consists generally of gas released from the decomposition of raw materials and thus has a low alkali content. Finally, it may also be advantageous to extract a portion of the flue gas from the clarification tank, since the flue gas in the clarification tank contains even more alkali due to the higher temperature required for clarification.

[0111] Furthermore, it is further advantageous in the present invention that the flue gas (at least a large part of it) generated by the decomposition of the raw material in the upstream Z1 of the main melting tank can be almost independent of the flue gas from the combustion (in zone Z2 and / or The clarification tank) is extracted (and thus processed). In fact, the NOx and SOx contents of flue gases that appear in zone Z1 are low, thus facilitating CO. 2 capture.

[0112] In an advantageous embodiment of the invention, such as Figure 4 As shown, the furnace of the present invention comprises a main melting tank M, which is laterally enlarged and equipped with inlet devices(s) X' and X' at each lateral side such that the main melting tank comprises Two different upstream regions Z1' and Z1' and two transition regions T' and T', where two opposing glass flows converge through central downstream region Z2.

[0113] In this configuration: - The height H1' of the melting furnace top C1' is defined by: H1'≤0.75*H2; - The height H1" of the melting furnace top C1" is defined by: H1"≤0.75*H2; -The length L1' of at least one upstream region Z1' is defined by: 0.25*(L1'+L2)≤L1'≤0.8*(L1'+L2); -The length L1" of at least one upstream region Z1" is defined by: 0.25*(L1"+L2)≤L1"≤0.8*(L1"+L2); -The length LT' of the transition zone T' is defined by: LT'≤0.2*(L1'+L2); and -The length LT" of the transition zone T" is defined by: LT"≤0.2*(L1"+L2).

[0114] In addition, in this configuration: - The main melting tank comprises a downstream furnace top C2 and two upstream furnace tops C1' and C1'. The furnace tops C1' and C1' can each be independently configured according to any embodiment of the invention related to the furnace top C1. For example, upstream furnace tops C1' and C1" may have the same or different heights H1' and H1"; -The main melting tank comprises two transition zones T' and T'. The two transition zones may each be configured independently according to any embodiment of the invention related to the transition zone T.

[0115] Furthermore, in this configuration, for example, the combustion heating device 3 is, Figure 4 The shown in the molten groove wall facing the neck is located, for example, two burners. Alternatively, for example, the combustion heating device 3 is located in the furnace top C2.

[0116] In this advantageous configuration / embodiment, each upstream area, each upstream furnace top and each inlet device are in accordance with the invention and embodiments thereof and may be independently of other upstream areas, other upstream respectively according to the above description. The furnace roof and other inlet devices are designed. Therefore, for the sake of clarity, the features described above with respect to Z1 are independently applicable to Z1' and Z1', the features described above with respect to C1 are independently applicable to C1' and C1', the features described above with respect to T are independently applicable to T. It is independently applicable to T' and T', and the features described above with respect to X are independently applicable to X' and X'. Furthermore, the specific advantageous features described with respect to M, C2, C3, C4, N, F, etc. are also applicable to this particular configuration, and the advantages are the same.

[0117] In addition, in this configuration, the auxiliary melting tank ( Figure 4 Not shown in this article may be located / connected at one of the upstream portions of the main melting tank M (eg in zone Z1'), more preferably as far as possible upstream of the main melting tank M (e.g. in zone Z1') ). Alternatively, the furnace may include two auxiliary melting tanks, including one auxiliary melting tank at each upstream portion of the main melting tank M (eg in zones Z1' and Z1"), more preferably, each upstream. Areas Z1' and Z1" include an auxiliary melting tank.

[0118] A specific glass furnace design is described in European Patent Application EP 21200998.9, which is incorporated by reference as an embodiment of the invention.

[0119] According to a particular embodiment, the furnace of the present invention is defined by the following: 0.1*W F ≤W N ≤0.6*W F ; W M ≥1.4*W N ; W M is the width of the melting tank M; W F is the width of the clarification groove F; W N It is the width of the neck-shaped part N.

[0120] This embodiment allows for the enhancement of the above advantages of the invention, as follows: - Better separate the atmosphere between the melting tank and the clarification tank, thereby limiting the return of corrosive flue gas from the clarification tank to the melting tank; - Enhance the cutting of thermal radiation from the clarification tank toward the melt tank; - Enhance the limit on the overall flow rate of molten glass or even eliminate reverse flow.

[0121] Also preferably, the furnace is from 0.2*W F ≤W N ≤0.6*W F , or even 0.3*W F ≤W N ≤0.5*W F limited. This allows for a good trade-off between the following two opposite requirements: On the one hand, the neck(s) between the melting zone and the clarification zone should ideally be as narrow as possible in order to (1) reduce the melting superstructure / The opening between the furnace top and the clarified superstructure / The furnace top, and (2) an obstacle to the overall strength of the glass melt convection in the melt tank, on the other hand, the neck should ideally be as wide as possible, In order to limit the glass speed inside the neck, thereby limiting the wear / corrosion of the refractory wall of the neck.

[0122] Also preferably, the furnace of the present invention is from M ≥1.5*W N , or even W M ≥1.8*W N limited. More preferably, the furnace of the present invention is from M ≥2*W N limited. This allows a higher width limit to be achieved at the neck N, and allows for improved cutoff of thermal radiation, allows for better atmosphere separation, and allows for a restriction on the flow rate of molten glass.

[0123] According to an embodiment, the furnace may include a melting tank and a neck-shaped portion; or two melting tanks and two neck-shaped portions; or even three melting tanks and three neck-shaped portions. These examples are widely described in European Patent Application EP 21200998.9, which is incorporated by reference herein.

[0124] exist Figure 5 In the specific "double melt tank" configuration shown, the furnace for melting the vitrified material includes two melt tanks M' and M', two neck-shaped portions N' and N' (one neck for each melt tank. and at least two inlet devices X' and X' (one inlet device for each melting tank).

[0125] Configuration with single melting tank ( Figure 3 ) This configuration is particularly advantageous in comparison, as this configuration allows: - Reduce the top span of each melt tank under the same total area of ​​the melt tank and the furnace length (length is usually more constrained than width). Reduction of furnace top span allows: (i) Reduce the stress inside the furnace roof material, thereby reducing the risk of material creep and furnace roof sag. Then, refractory materials with high corrosion resistance and low creep resistance, such as alumina or spinel, will be used to extend the furnace life; (ii) Reduce the furnace top average height in the case of the arched furnace top C1 and / or C2, thereby lowering the horizontal radiation transfer, and subsequently, in the case of the flue gas extracted from the melting tank, the flue gas is caused from the flue gas The heat transfer to the glass melt is better; -Total width in the same neck shape (W N' +W N” ) and in the case of the neck-shaped furnace top C3 in the arch-shaped shape, the opening surface between the melting tank and the clarification tank is reduced; -Total width in the same neck shape (W N' +W N” ) reduces the strength of glass convection in the molten tank; -Make furnace maintenance easier in the melting zone. In fact, using two melt tanks, one melt tank can be isolated from the rest of the furnace and allowed to cool while producing with the other melt tank. The total life of the furnace can then be extended by replacing the worn refractory material in the melting area (the area that is the most critical in terms of wear / corrosion).

[0126] In this configuration, the furnace has two melting tanks M', M', each melting tank has its upstream region Z1' or Z1', its upstream furnace top C1' or C1', its downstream region Z2' or Z2', Its transition zone T' or T', and its inlet device X' or X'. In addition, each of the melting tanks M' and M'" is separated from the clarification tank F by the neck-shaped portions N' and N', respectively.

[0127] In addition, in this configuration, the auxiliary melting tank ( Figure 5 Not shown in this) may be located / connected at one of the upstream portions of the main melting tank M' (eg, in zone Z1'), more preferably as far as possible upstream of the main melting tank M' (especially in zone Z1'). 'middle). Alternatively, the furnace may include two auxiliary melting tanks, including one auxiliary melting tank at each upstream portion of the main melting tanks M' and M', more preferably at each upstream region Z1' and Z1'. An auxiliary melting tank.

[0128] In this configuration, according to the invention: - The height H1' of the melting furnace top C1' is defined by: H1'≤0.75*H2'; - The height H1" of the melting furnace top C1" is defined by: H1"≤0.75*H2"; -The length L1' of the upstream area Z1' is defined by: 0.25*(L1'+L2')≤L1'≤0.8*(L1'+L2'); and -The length L1" of at least one upstream region Z1" is defined by: 0.25*(L1"+L2")≤L1"≤0.8*(L1"+L2"); -The length LT' of the transition zone T' is defined by: LT'≤0.2*(L1'+L2'); and -The length LT" of the transition zone T" is defined by: LT"≤0.2*(L1"+L2").

[0129] Furthermore, in this configuration, the furnace can advantageously be defined by: 0.1*W F ≤W N' ≤0.6*W F ; 0.1*W F ≤W N” ≤0.6*W F ; W M' ≥1.4*W N' ; W M' ≥1.4*W N” ; W M' is the width of the melting tank M'; W M” is the width of the melting tank M”; W F is the width of the clarification groove F; W N' It is the width of the neck-shaped portion N'. W N' It is the width of the neck-shaped part N".

[0130] In addition, in this configuration: -The upstream and downstream regions may each be configured independently according to any embodiment of the invention related to Z1 and Z2. - The furnace tops C1' and C1" may each be independently configured according to any embodiment of the invention related to the furnace top C1. For example, the upstream furnace tops C1' and C1" may have the same or different heights H1' and H1"; - The furnace tops C2' and C2" may each be independently configured according to any embodiment of the invention related to the furnace top C2. For example, the furnace tops C2' and C2" may have the same or different heights H2' and H2"; and - Transition zones T' and T" may each be configured independently according to any embodiment of the invention related to transition zone T.

[0131] In this advantageous configuration / embodiment, each melting tank, each upstream area, each downstream area, each transition area, each neck and each inlet device are in accordance with the invention and embodiments thereof , and can be designed independently of other melting tanks, other upstream areas, other downstream areas, other transition areas, other neck-shaped parts and other inlet devices according to the above description. Therefore, for the sake of clarity, the features described above with respect to M are independently applicable to M' and M', the features described above with respect to Z1 are independently applicable to Z1' and Z1', the features described above with respect to C1 are independently applicable to features described above with respect to C1. Independently applicable to C1' and C1", the features described above with respect to Z2 are independently applicable to Z2' and Z2", the features described above with respect to C2 are independently applicable to C2' and C2", the features described above with respect to T The described features are independently applicable to T' and T', and the features described above with respect to X are independently applicable to X' and X'.

[0132] Furthermore, the specific advantageous features described with respect to furnaces with single melt tanks (eg those described with respect to C3, C4, F) are applicable to this "double melt tank" configuration, and the advantages are the same.

[0133] In a "double melt tank" furnace according to an embodiment, the two melt tanks M' and M" are preferably passed by a width W located at the clarification tank F. F The two neck-shaped parts N', N" in the "subtitle" are connected to the clarification groove F (eg Figure 5 as shown). Alternatively, in a "double melt tank" configuration, one melt tank passes through a width W located at the clarification tank F The neck-like part in the middle is connected to the clarification groove, and the second melting groove is located in the length of the clarification groove (right or left) and close to the upstream of the clarification groove (ie, in the first third of the length of the clarification groove The neck-like portion of the clarification groove is connected to the clarification groove. For example, this latter configuration may be advantageous when the space present in the device containing the furnace is insufficient to place two melting tanks side by side.

[0134] In a "double melt tank" configuration, two melt tanks pass through a width W located at the clarification tank. F In the case where the neck-like portion in the middle is connected to the clarification groove, the distance D between the two melting grooves is preferably at least 1 m, more preferably at least 2 m, or more preferably at least 3 m. This is advantageous as this allows access to the zone for maintenance operations and for outer coating of the groove wall.

[0135] In an alternative embodiment of the invention, the furnace is in a configuration with three melting tanks, three necks and three inlet devices. This embodiment is particularly advantageous in the same manner as the "double melt tank" configuration as the "double melt tank" configuration. In this "three melt tank" configuration, each neck-shaped portion, each melt tank and each inlet device are in accordance with the present invention and embodiments and may be independent of other neck-shaped portions, other respectively according to the above description. Melting tanks and other inlet devices are designed.

[0136] The specific advantageous features described with respect to furnaces with "single melt tank" configurations and with "double melt tank" configurations are applicable to "three melt tank" configurations, with the same advantages.

[0137] In a "three melt tank" furnace according to an embodiment, at least two melt tanks pass through a width W located at the clarification tank. F In the case where the neck-like portion in the middle is connected to the clarification groove, the distance D between the two adjacent melting grooves is preferably at least 1 m, more preferably at least 2 m, or more preferably at least 3 m.

[0138] In all furnace configurations according to the invention (ie, "single melt tank" configuration, "double melt tank" configuration and "three melt tank" configuration) each may be used to facilitate the distribution of the vitrified material to be fed to be fed for each The melting tank is provided with more than one inlet device, ie, two inlet devices per each inlet channel.

[0139] Preferably, the total surface area of ​​the melting tank(s) is 25m 2 To 400m 2 . Also preferably, according to the invention, the surface area of ​​the clarification tank F is in the range of 25 m. 2 To 400m 2 .

[0140] According to the invention and Figure 1 As shown, a method for melting a vitrified material to produce flat glass includes the step of loading the vitrified material into the main melt tank M with at least one inlet device X, which are glassable The chemical material includes raw materials and broken glass.

[0141] According to the invention, the amount of broken glass is at least 10% by weight of the total amount of vitrified material. Preferably, the amount of broken glass is at least 20% by weight of the total amount of vitrified material. More preferably, the amount of broken glass is at least 30% by weight, or even very preferably at least 40% by weight, of the total amount of vitrified material. This is advantageous because it allows for a reduction in CO of the process of the invention 2 generation / emission (due to reduced emissions generated by decarbonization of carbonate raw materials). It is also preferred that the amount of broken glass is at most 90% by weight, or even at most 80% by weight, of the total amount of vitrified material. More preferably, the amount of broken glass is at most 70% by weight, or even at most 60% by weight, of the total amount of vitrified material.

[0142] According to the invention and Figure 1 As shown, the method further comprises the step of premelting at least a portion of the broken glass in the auxiliary melt tank and causing the premelting broken glass to flow to the main melt tank.

[0143] According to the invention, the portion of the broken glass to be pre-melted is loaded into the auxiliary melting tank, and the remaining portion of the broken glass (unpre-melted portion, if any) is loaded into the main melting tank. Since this embodiment allows the use of poor quality broken glass or contaminated broken glass in the process of the invention, this embodiment has the advantage of avoiding the lack of available high-quality broken glass. In fact, in this embodiment, at least a portion of the broken glass is "digested" in the auxiliary melting tank in advance. For example, by using a reducing agent (such as coke or anthracite) to produce a molten metal, the metal compound present in the broken glass can be eliminated in the auxiliary melt tank, which will melt with the glass by decanting at the bottom of the auxiliary melt tank The body is separated and the obtained "purified" glass melt can flow from the top to the main melt tank.

[0144] According to an embodiment, the remaining portion of the broken glass (unpre-melted portion, if any) is loaded with the raw material into the main melting tank (ie through the same inlet device(s) X), or alternatively, Independently from the raw material, it is loaded into the main melt tank through different inlet devices(s).

[0145] Also according to the embodiment, only a portion of the broken glass is pre-melted in the auxiliary melting tank. For example, the portion of the broken glass that is considered "contaminated" or not clean enough is pre-melted in the auxiliary melting tank, and the remaining "cleaning" portion of the broken glass is loaded into the main melting tank. Alternatively, the total amount of broken glass is pre-melted in the auxiliary melting tank.

[0146] According to an embodiment of the invention, at least a portion of the broken glass pre-melted in at least one auxiliary melting tank accounts for at least 2% by weight, and preferably at least 5% by weight, or even at least 10% by weight, and More preferably at least 20% by weight. According to another embodiment of the invention, at least a portion of the broken glass pre-melted in at least one auxiliary melting tank accounts for at least 60% by weight, and preferably at most 50% by weight, or even at most 40% by weight, of the total amount of broken glass, of which is preferably at most 50% by weight, or even at most 40% by weight, of the total amount of broken glass. .

[0147] Alternatively, the total amount of broken glass is pre-melted in the auxiliary melting tank (meaning that only the raw material from the vitrified material of the invention is loaded into the main melting tank).

[0148] According to the invention, the step of pre-melting at least a portion of the broken glass can be performed in the auxiliary melting tank with an electrical heating device (such as an immersion electrode) and / or with a combustion device (such as an air burner or immersion combustion device).

[0149] According to an embodiment, the step of pre-melting at least a portion of the broken glass may be performed in two auxiliary melting tanks.

[0150] According to the invention and Figure 1 As shown, the method for melting the vitrified material to produce flat glass includes the step of melting the vitrified material in the melt tank M by heating with a heating device (ie, an electric heating device 2 and a combustion heating device 3).

[0151] According to the invention and Figure 1 The method for melting a vitrified material to produce flat glass includes the step of clarifying the melt in the clarification tank F by heating with an oxygen combustion heating device 3', which is supplied with gas and / Or hydrogen. The term "gas" herein includes but is not just natural gas, syngas and biogas. Natural glass is currently the most widely used for reasons of practicality, economicality and availability.

[0152] According to the present invention, the oxygen combustion heating device 3' is supplied with gas and / or hydrogen. In an embodiment, the oxygen combustion heating device 3' is supplied with at least 50% hydrogen, preferably at least 80% hydrogen. More preferably, the oxygen combustion heating device 3' is supplied with 100% hydrogen. This is advantageous because it allows a substantial reduction in overall CO of the method 2 emission. In an alternative, the oxygen combustion heating device is supplied with more than 50% gas, preferably at least 80% gas, or even at least 100% gas. This is advantageous because it allows higher CO in the flue gas 2 concentration, thereby promoting and improving CO 2 Capture steps, and limit the effects on the chemical properties of the glass and the furnace refractory material. In a specific and advantageous embodiment of the invention, the oxygen combustion heating device 3' is supplied with 50% gas and 50% hydrogen.

[0153] According to the invention, the electrical input fraction in the method ranges from 30% to 85%. "Electric input fraction" according to the invention refers to the power part for melting / clarifying in the total energy input of the method / furnace, ie, electric power / (fuel + electric power), the total energy input is the method / furnace in standard / normal The total energy input in the production mode, that is, the total energy input under its standard output range (excluding the time period of startup, maintenance, thermal repair, fragmented glass...). Preferably, the electrical input fraction ranges from 35% to 85%, more preferably from 40% to 85%.

[0154] According to the invention and Figure 1 The method for melting a vitrified material to produce flat glass as shown includes the step of flowing the melt from the clarification tank F to the working area through the outlet device O.

[0155] According to the invention, the outlet device O is located downstream of the clarification tank F for the molten glass to reach the working area. According to an embodiment, the outlet device is usually composed of a neck-shaped portion to direct the melt to the working area, which is commonly referred to as the "working end". Alternatively, the outlet device is formed of a throat-like portion to direct the melt to a working area including, for example, a fork furnace(s). The working area according to the invention may include, for example, a regulating zone in which the glass melt is thermally adjusted by controlled cooling before leaving the zone through the outlet to reach the molding zone. Such forming zones may include, for example, float facilities and / or rolling facilities.

[0156] According to the invention and Figure 1 As shown, a method for melting a vitrified material to produce flat glass includes capturing CO from flue gas 2 steps.

[0157] According to the invention, the flue gas (ie, undergoes CO 2 Capture step flue gas) has at least 35% CO 2 concentration. CO according to the invention 2 The concentration is for dry flue gas (ie, with water removal (H) 2 The concentration defined by all components of the flue gas) except O) is defined. Preferably, the flue gas in the present invention has at least 40% CO 2 Concentration, more preferably at least 50% CO 2 Concentration, or even higher at least 60% CO 2 concentration. This is advantageous because the CO of the flue gas 2 The higher the concentration, the CO applied to the flue gas 2 The easier and more effective it is to capture.

[0158] According to the invention, CO is captured from flue gas 2 The steps include compression and / or dehydration steps. The dehydration step corresponds to the water condensation and / or drying step of the flue gas. The compression step corresponds to the increase of CO usually by using a compressor 2 pressure. The dehydration step may be prior to the compression step, and / or the dehydration step may be accompanied by the compression step.

[0159] In particular, the capture of CO from the flue gas according to the invention 2 The steps can be used to use CO 2 The compression and purification unit (or CPU) is performed in a known manner.

[0160] like Figure 1As shown, the flue gas according to the invention can be recovered from the melt tank M, or from the clarification tank F, or from both for CO 2 capture. In particular, if only hydrogen is supplied with the oxygen combustion heating device 3' according to the invention, the flue gas is advantageously recovered only from the melting tank M (the flue gas discharged from the clarification tank F does not contain CO. 2 ).

[0161] Capture CO in accordance with the invention 2 After the steps, CO 2 The product, for example, has a pressure of about 35 bar at a temperature of 5°C to 40°C, is in a gaseous form, is suitable for transport by pipe, or has about 100 bar, is in a liquid form, is suitable for transport by pipe but is also suitable for transport by truck or rail. . For trucking, it is also known that a value of 15 bar gauge pressure at -35°C is suitable.

[0162] This simple and effective CO 2 The capture method is very advantageous because it allows the avoidance of any adsorbents / chemical reagents that can cause operational / energy costs and environmental problems, and because it allows cost-effective CO to be achieved 2 Capture makes the entire method of the invention economically feasible.

[0163] According to a preferred embodiment, CO is captured from the flue gas 2 The steps generally consist of compression and / or dehydration steps.

[0164] According to an advantageous embodiment, the method of the invention further comprises the step of eliminating the acidic component from the flue gas. This step of eliminating acidic components is captured in CO 2 The steps are performed before or simultaneously with them (e.g. before or simultaneously with the compression and / or dehydration steps).

[0165] The step of eliminating the acidic component may include the step of desulfurizing the flue gas (or removing the so-called SOx compound). It may also include the step of removing so-called NOx compounds, which may still exist, even if the amount of these compounds is very low due to the use of oxygen as a combustion aid. This is advantageous because this allows the removal of corrosive compounds (SOx, NOx) prior to transportation, storage and / or use.

[0166] Capture CO in accordance with the invention 2 After the steps, in a known manner, CO 2 The product (eg, in liquid form) can be transported to its final destination by pipe and then stored / sealed (eg, deep seabed or geological formations, such as groundwater layers with high saline content), or alternatively used ( For example, for improving oil recovery, or for food / beverage applications, or for fire protection applications). Advantageously, in capturing CO 2 After the steps obtained 2 The product can be used locally to limit transportation. If the captured CO 2 The amount is not too high, so that it can be absorbed by the local market, so you can consider doing so.

[0167] According to an advantageous embodiment of the invention, the method further comprises the step of preheating the broken glass by at least partially recovering heat from the furnace 1 before loading the broken glass into the main melting tank M. According to this embodiment, the recovery of heat from the furnace 1 can be from the flue gas from (i) the main melting tank M or (ii) the clarification tank F, or (iii) from the entire furnace (hereby including from the melting tank and clarification tank Flue gas).

[0168] According to this embodiment and advantageously, CO 2 The capture step may be performed by the flue gas used in the broken glass preheating step.

[0169] Also according to this embodiment, the raw material is loaded into the main melting tank M with the preheated broken glass through the same inlet device(s) X (so that this means that the two types of vitrified materials are mixed before loading) . Alternatively, the raw material is loaded into the main melt tank M independently of the preheated broken glass by different inlet devices(s).

[0170] Preferably, according to this embodiment, in the preheating step of crushed glass, the maximum temperature of crushed glass is 450°C. This allows avoiding clogging issues.

[0171] According to an embodiment, the step of preheating of broken glass may be performed in at least one broken glass preheater, for example, in a type of broken glass preheater of one of those described in US 5526580 or DE 3716687.

[0172] Advantageously, the at least one broken glass preheater can be located at an upstream portion of the groove over the width of the melting groove or laterally in its length. Advantageously, the step of preheating of broken glass can be carried out in at least two broken glass preheaters, such as on both sides of the width of the melting tank or laterally on their length. Located at the upstream part of the melting tank. For example, the step of preheating of broken glass may be performed in four broken glass preheaters located at an upstream portion of the melting tank, distributed over the width of the melting tank, or laterally therein in length (eg, two on each side). For example, the step of preheating of broken glass may be carried out in six broken glass preheaters that are either on the width of the melting tank or laterally on their length (eg, three on each side. ) is located at the upstream part of the melting tank, or the preheating of the broken glass can also be carried out in eight broken glass preheaters, which are on the width of the melting tank or laterally therein. In length (eg, four on each side) are located at the upstream portion of the melting tank.

[0173] According to another embodiment of the invention, the method further comprises the step of preheating at least a portion of the broken glass by recovering heat from the furnace 1 before loading at least a portion of the broken glass into the auxiliary melting tank.

[0174] According to another advantageous embodiment of the invention, the raw material comprises less than 25% by weight of the carbonate compound. "Carbonate compound" means, for example, alkali metal carbonates and alkaline earth metal carbonates. Preferably, the raw material comprises less than 20% by weight, more preferably less than 10% by weight, even less than 5% by weight of the carbonate compound. The raw material may advantageously be free of any carbonate compounds.

[0175] This example is advantageous because with sodium carbonate Na 2 CO 3 , limestone CaCO 3 and dolomite CaMg(CO 3 ) 2 Compared to classic glass melting methods, which are generally used as a source of sodium, calcium and magnesium, this embodiment allows for reduced CO produced by decarbonization of raw materials. 2 Emission part. According to this embodiment, the alkali metal and alkaline earth metal sources can advantageously be at least partially oxides or hydroxides (such as CaO, CaO.MgO (calcined dolomite), Ca(OH) 2 , Mg(OH) 2 , NaOH, KOH) exists in the form of.

[0176] According to a very preferred embodiment of the invention, the method for melting a vitrified material to produce flat glass comprises the following steps: - Provides a furnace, which includes: (i) a main melting tank M, the main melting tank includes at least one upstream area Z1 covered by the furnace top C1 and equipped with an electric heating device 2 , a downstream area Z2 covered by the furnace top C2 and equipped with a combustion heating device 3 , and In the transition zone T between the furnace top C1 and the furnace top C2; (ii) Auxiliary melting tank, (iii) A clarification tank F, which is covered by the furnace top C4 and equipped with an oxygen combustion heating device 3', (iv) The neck-shaped portion N is covered by the furnace top C3 and separates the main melting tank M and the clarification tank F, (v) at least one inlet device X located at the main melting tank M; (vi) the outlet device O located downstream of the clarification tank F; and (vii) at least one flue gas extraction device located at at least one upstream area Z1; The height H1 of the furnace top C1 of the furnace is defined by: H1≤0.75*H2; H2 is the height of the furnace top C2, and the length L1 of at least one upstream area Z1 is defined by: 0.25*(L1+L2)≤L1≤ 0.8*(L1+L2); L2 is the length of the downstream region Z2, and the length LT of the transition region T is defined by: LT≤0.2*(L1+L2), - Filling a vitrified material into a main melting tank with at least one inlet device, the vitrified material comprising (i) a raw material having less than 25% by weight of carbonate compound and ( ii) is a broken glass in an amount of at least 10% by weight of the total amount of the vitrified material, - preheating of the broken glass by at least partly by recovering heat from the furnace before the broken glass is loaded into the main melting tank and / or the auxiliary melting tank; - Pre-melting at least a portion of the broken glass in the auxiliary melting tank and causing the pre-melting broken glass to flow to the main melting tank; - Use heating devices 2 and 3 to melt the vitrified material in the main melting tank; - The melt in the clarification tank F is clarified by heating with an oxygen combustion heating device 3', which is supplied with gas and / or hydrogen; - Flow the melt through the outlet device O from the clarification tank F to the working area; -Catch CO from flue gas 2 , the flue gas has at least 35% CO 2 concentration; where the electrical input fraction ranges from 30% to 85%, and where CO is captured from the flue gas 2 The steps include compression and / or dehydration steps.

[0177] All previously described specific embodiments related to each step of the method of the invention are applicable to this last very preferred embodiment.

[0178] Those skilled in the art recognize that the invention is by no means limited to the preferred embodiments described above. Rather, many modifications and variations are possible within the scope of the appended claims. It should be further noted that the invention relates to all possible combinations of features and preferred features described herein and stated in the claims.

Claims

1. A method for melting a vitrifiable material to produce flat glass, the method comprising the following steps: - Providing a furnace 1, said furnace comprising: (i) a main melting tank M, comprising at least one upstream zone Z1 covered by a furnace roof C1 and equipped with an electric heating device 2, a downstream zone Z2 covered by a furnace roof C2 and equipped with a combustion heating device 3, and a transition zone T between the furnace roofs C1 and C2; (ii) auxiliary melting tank; (iii) a clarification tank F, which is covered by a furnace roof C4 and is equipped with an oxygen combustion heating device 3', (iv) a neck portion N which is covered by the furnace roof C3 and separates the main melting tank M from the clarification tank F, (v) at least one inlet device X located at the main melting tank M; (vi) an outlet device O located downstream of the clarification tank F; and (vii) at least one flue gas extraction device located at said at least one upstream zone Z1; The height H1 of the furnace roof C1 of the furnace is defined by: H1≤0.75*H2; H2 is the height of the furnace roof C2, the length L1 of the at least one upstream zone Z1 is defined by: 0.25*(L1+L2)≤L1≤0.8*(L1+L2); L2 is the length of the downstream zone Z2, and the length LT of the transition zone T is defined by: LT≤0.2*(L1+L2), - charging the vitrifiable material into the main melting tank M and / or the auxiliary melting tank having the at least one inlet device X, the vitrifiable material comprising raw materials and cullet, the amount of cullet being at least 10% by weight of the total amount of the vitrifiable material; - pre-melting at least a portion of the cullet in the auxiliary melting tank, and allowing the pre-melted cullet to flow to the main melting tank; - melting the vitrifiable material in the main melting tank M using the heating device 2; 3; - fining the melt in the fining tank F by heating with the oxygen combustion heating device 3 ′, the oxygen combustion heating device being supplied with gas and / or hydrogen; - allowing the melt to flow from the clarification tank F to the working area through the outlet device O; - Capturing CO2 from flue gas, said flue gas having a CO2 concentration of at least 35%; wherein the electricity input fraction ranges from 30% to 85%, and wherein the step of capturing CO2 from the flue gas comprises a compression and / or dehydration step.

2. Method for melting a vitrifiable material according to the preceding claim, characterized in that The amount of cullet is at least 30% by weight of the total amount of vitrifiable material.

3. The method for melting a vitrifiable material according to the preceding claim, characterized in that The oxy-combustion heating device is supplied with at least 50% hydrogen, preferably at least 80% hydrogen.

4. Method for melting a vitrifiable material according to the preceding claim, characterized in that The flue gas has a CO2 concentration of at least 40%.

5. Method for melting a vitrifiable material according to the preceding claim, characterized in that The flue gas has a CO2 concentration of at least 50%.

6. Method for melting a vitrifiable material according to the preceding claim, characterized in that The steps of capturing CO2 from flue gases generally consist of a compression and / or a dehydration step.

7. Method for melting a vitrifiable material according to the preceding claim, characterized in that The method further comprises the step of eliminating acidic components from the flue gas.

8. Method for melting a vitrifiable material according to the preceding claim, characterized in that The step of eliminating acidic components from the flue gas is carried out before or simultaneously with the step of capturing CO2.

9. Method for melting a vitrifiable material according to the preceding claim, characterized in that The method further comprises the step of preheating the cullet before charging the cullet into the melting tank M, at least in part by recovering heat from the melting furnace.

10. The method for melting a vitrifiable material according to claim 9, characterized in that The maximum temperature of the cullet in the cullet preheating step is 450°C.

11. Method for melting a vitrifiable material according to the preceding claim, characterized in that The raw material contains less than 25% by weight of carbonate compounds.

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