Glass manufacturing method and glass manufacturing apparatus

Abstract

To provide a technique of reducing H2O gas concentration in a furnace atmosphere of a glass melting furnace in the case of using H2 gas as flammable gas.SOLUTION: A glass manufacturing method has: generating at least CO gas from CO2 gas and H2 gas by reaction in which overall reaction is expressed by formula (1) or formula (2) in the specification; and forming a flame inside the glass melting furnace by burning flammable gas containing the generated CO gas and oxidizing gas by a burner.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to glass manufacturing methods and glass manufacturing apparatus. [Background technology]

[0002] The glass manufacturing apparatus includes a burner that forms a flame inside a glass melting furnace. The burner forms the flame by burning a combustible gas and a combustion-supporting gas. The combustible gas is, for example, natural gas. The natural gas contains CH4 gas as a main component. The combustion-supporting gas is, for example, pure oxygen gas or air. The flame heats glass raw materials and molten glass obtained by melting the glass raw materials.

[0003] As mentioned above, air is sometimes used as the combustion supporting gas. In this case, since N2 gas, which makes up the majority of the air, does not contribute to combustion, a large amount of air is used, and a large amount of combustion gas is discharged from the glass melting furnace. Combustion gas refers to the gas remaining after the combustion reaction between combustible gas and combustion supporting gas (including N2 gas, which does not contribute to the combustion reaction). In order to recover the heat from the large amount of combustion gas discharged, a first regenerator and a second regenerator are sometimes installed next to the glass melting furnace.

[0004] The first and second heat regenerators are used in combination with the first and second burners. The glass manufacturing apparatus alternately and repeatedly performs the first burner to form a flame inside the glass melting furnace and the second burner to form a flame inside the glass melting furnace.

[0005] The first regenerator recovers heat from the combustion gas discharged from the glass melting furnace while the second burner forms a flame inside the glass melting furnace. The first regenerator releases the previously recovered heat to heat at least one of the combustible gas and the combustion-supporting gas while the first burner forms a flame inside the glass melting furnace. The first burner forms a flame inside the glass melting furnace by combusting the combustible gas and the combustion-supporting gas heated in the first regenerator.

[0006] Similarly, the second regenerator recovers heat from the combustion gas discharged from the glass melting furnace while the first burner forms a flame inside the glass melting furnace. The second regenerator releases the previously recovered heat to heat at least one of the combustible gas and the combustion-supporting gas while the second burner forms a flame inside the glass melting furnace. The second burner forms a flame inside the glass melting furnace by combusting the combustible gas and the combustion-supporting gas heated in the second regenerator.

[0007] The first heat regenerator in Patent Document 1 releases heat while the first burner forms a flame inside the glass melting furnace to promote an endothermic reaction. As an example of the endothermic reaction, a reaction is disclosed in which CO gas and H gas are produced from CH gas, H2O gas, and CO2 gas. The CO gas and H2 gas produced in the first heat regenerator are supplied to the first burner as combustible gases.

[0008] As mentioned above, pure oxygen gas may be used as the combustion-supporting gas. In this case, the combustion-supporting gas does not contain N2 gas. Therefore, the amount of combustion gas discharged is small and a heat regenerator is not required, which increases the degree of freedom in the design of the glass melting furnace. In addition, N2 gas, which does not contribute to combustion, is not heated unnecessarily, and the glass can be heated efficiently using the combustion heat. Furthermore, NO X Gas generation can be suppressed.

[0009] As a means for recovering heat from the combustion gas discharged from the glass melting furnace, a recuperator may be used instead of a regenerator.

[0010] The recuperator in Patent Document 2 heats air by heat exchange with combustion gas. The air transports heat from the recuperator to the reactor. The reactor heats natural gas by heat exchange with the air heated in the recuperator, and the C contained in the natural gas is m H n An endothermic reaction occurs in which CH4 gas is produced from the gas (m and n are integers of 2 or greater).

[0011] Patent Document 3 discloses that if the H2O gas concentration in the atmosphere inside a glass melting furnace is too high, the moisture concentration in the molten glass will be too high, resulting in a decrease in glass quality (for example, defects will occur on the bottom surface of float glass). [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent No. 3705713 [Patent Document 2] Patent No. 6980795 [Patent Document 3] Patent No. 6144622 Summary of the Invention [Problem to be solved by the invention]

[0013] Natural gas is generally used as the combustible gas burned in a burner. Natural gas contains CH4 gas as its main component. When CH4 gas is burned, CO2 gas is generated. Therefore, in order to reduce the amount of CO2 gas generated and therefore CO2 gas emissions, it is possible to use H2 gas instead of CH4 gas.

[0014] When H2 gas is burned instead of CH4 gas, the reaction between H2 gas and O2 gas generates H2O gas, but no CO2 gas is generated. However, the absence of CO2 gas results in a higher H2O gas concentration in the furnace atmosphere. This is particularly noticeable when pure oxygen gas is used as the combustion-supporting gas. When pure oxygen gas is used, the H2O gas concentration in the furnace atmosphere can theoretically reach 100% by volume.

[0015] Note that glass frits may release gases during melting. For example, if the frits contain carbonates such as calcium carbonate or magnesium carbonate, they will release CO gas during melting. Therefore, the HO gas concentration in the furnace atmosphere is actually less than 100% by volume.

[0016] If the HO gas concentration in the furnace atmosphere is too high, NaOH gas derived from the Na contained in the molten glass is likely to be generated, which can corrode furnace materials such as bricks. Alternatively, if the HO gas concentration in the furnace atmosphere is too high, the water concentration in the molten glass can become too high, which can result in poor glass quality.

[0017] One aspect of the present disclosure provides a technique for reducing the H2O gas concentration in the furnace atmosphere of a glass melting furnace when H2 gas is used as a combustible gas. [Means for solving the problem]

[0018] A glass manufacturing method according to one embodiment of the present disclosure includes generating at least CO gas from CO gas and H gas by an overall reaction represented by the following formula (1) or (2): and burning the generated flammable gas containing CO gas and a combustion-supporting gas with a burner to form a flame inside a glass melting furnace:

[0019] [ka]

[0020] [ka] [Effects of the Invention]

[0021] According to one aspect of the present disclosure, when H gas is used as a combustible gas, H gas and CO gas are converted to produce at least CO gas, and the resulting combustible gas containing CO gas and a combustion-supporting gas are combusted with a burner. This reduces the HO gas concentration in the combustion gas and the HO gas concentration in the furnace atmosphere of a glass melting furnace. [Brief explanation of the drawings]

[0022] [Figure 1]FIG. 1 is a diagram showing a glass manufacturing apparatus according to one embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a reaction (x=0.5) in which the overall reaction is represented by formula (1). [Figure 3] FIG. 3 is a diagram showing examples 1 to 14 of combinations of combustible gas, combustion-supporting gas, H2O gas concentration in the combustion gas, and H2O gas concentration in the furnace atmosphere. [Figure 4] FIG. 4 is a diagram showing a first embodiment of a glass manufacturing apparatus including a recuperator and a reactor. [Figure 5] FIG. 5 shows a second embodiment of a glass manufacturing apparatus including a recuperator and a reactor. [Figure 6] FIG. 6 shows a third embodiment of a glass manufacturing apparatus including a recuperator and a reactor. [Figure 7] FIG. 7 is a diagram showing a first embodiment of a glass manufacturing apparatus including a first heat storage chamber and a second heat storage chamber. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their description may be omitted. In the specification, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0024] A glass manufacturing apparatus 1 according to one embodiment will be described with reference to Fig. 1. The glass manufacturing apparatus 1 includes a glass melting furnace 10. The glass melting furnace 10 contains glass raw materials and molten glass obtained by melting the glass raw materials. After being removed from the glass melting furnace 10, the molten glass is formed into a desired shape and slowly cooled. This produces a glass product.

[0025] The glass frit is prepared by mixing a plurality of materials. The glass frit may contain a fining agent. The glass frit may contain glass cullet in order to recycle the glass. The glass frit may be a powder raw material or a granulated raw material obtained by granulating the powder raw material. The glass frit is determined depending on the composition of the glass product.

[0026] The glass melting furnace 10 is made of refractory bricks. Examples of the refractory bricks include electroformed zirconia bricks, electroformed alumina bricks, electroformed alumina-zirconia bricks, electroformed AZS (Al-Zr-Si) bricks, and dense-fired bricks. The glass melting furnace 10 may be made of multiple types of refractory bricks.

[0027] The glass manufacturing apparatus 1 includes a burner 20. The burner 20 generates a flame inside the glass melting furnace 10. The flame heats the glass frit and the molten glass. The glass frit is added from above to the surface of the molten glass, forming a layer on at least a portion of the surface. The glass frit gradually melts into the molten glass. Although only one burner 20 is shown in FIG. 1, there are usually multiple burners 20.

[0028] Glass manufacturing apparatus 1 may also use multiple electrodes (not shown) as a heat source. The multiple electrodes apply an AC voltage to the molten glass, thereby electrically heating the molten glass. In this case, the molten glass generates heat. Glass manufacturing apparatus 1 may also use an electric heater (not shown) as a heat source. The electric heater generates heat itself. Glass manufacturing apparatus 1 is only required to be equipped with at least burner 20 as a heat source.

[0029] The burner 20 forms a flame by burning a combustible gas and a combustion-supporting gas. In this embodiment, H2 gas (more specifically, a gas obtained by transforming H2 gas, as described below) is used as at least a part of the combustible gas. By using H2 gas, the amount of CO2 gas generated and therefore the amount of CO2 gas emitted can be reduced compared to when CH4 gas is used.

[0030] It is sufficient to use H2 gas as at least a part of the combustible gas, and natural gas may be used in combination. Since natural gas contains CH4 gas as a main component, the less natural gas used, the better. From the viewpoint of reducing the amount of CO2 gas generated, the amount of natural gas used is preferably 0% to 50% by volume, more preferably 0% to 25% by volume, and even more preferably 0% by volume.

[0031] When H2 gas is burned instead of CH4 gas, the reaction between H2 gas and O2 gas generates H2O gas, but no CO2 gas is generated. However, the absence of CO2 gas results in a higher H2O gas concentration in the furnace atmosphere. This is particularly noticeable when pure oxygen gas is used as the combustion-supporting gas. When pure oxygen gas is used, the H2O gas concentration in the furnace atmosphere can theoretically reach 100% by volume.

[0032] Note that glass frits may release gases during melting. For example, if the frits contain carbonates such as calcium carbonate or magnesium carbonate, they will release CO gas during melting. Therefore, the HO gas concentration in the furnace atmosphere is actually less than 100% by volume.

[0033] If the HO gas concentration in the furnace atmosphere is too high, NaOH gas derived from the Na contained in the molten glass is likely to be generated, which can corrode furnace materials such as bricks. Alternatively, if the HO gas concentration in the furnace atmosphere is too high, the water concentration in the molten glass will be too high, which can result in poor glass quality.

[0034] If air is used as the combustion-supporting gas instead of pure oxygen gas, the concentration of H2O gas in the furnace atmosphere can be reduced. In this case, since N2 gas, which makes up the majority of the air, does not contribute to combustion, a large amount of air is used, and a large amount of combustion gas is discharged from the glass melting furnace. Combustion gas refers to the gas (including N2 gas, which does not contribute to combustion) remaining after the combustion reaction between combustible gas and combustion-supporting gas. To recover the heat from the large amount of combustion gas discharged, a heat regenerator is installed next to the glass melting furnace 10.

[0035] On the other hand, if pure oxygen gas is used as the combustion supporting gas, the combustion supporting gas does not contain N2 gas. Therefore, the amount of combustion gas discharged is small and a heat regenerator is not required, which increases the degree of freedom in the design of the glass melting furnace 10. In addition, it is possible to avoid wasting heat on N2 gas that does not contribute to combustion, and the glass can be efficiently heated by the combustion heat. Furthermore, NO X Gas generation can be suppressed.

[0036] However, if pure oxygen gas is used as the combustion-supporting gas, the HO gas concentration in the furnace atmosphere will be higher than when air is used. If oxygen-enriched air is used as the combustion-supporting gas instead of pure oxygen gas, the HO gas concentration will also be higher than when air is used. Oxygen-enriched air is a mixed gas of pure oxygen gas and air, and has a higher oxygen gas concentration than air.

[0037] The glass manufacturing apparatus 1 of this embodiment includes a gas transformation unit 30 that transforms H gas to reduce the H2O gas concentration in the furnace atmosphere. One or more gas transformation units 30 (one in FIG. 1) are provided. The gas transformation unit 30 generates at least CO gas and H2O gas from CO2 gas and H2 gas through an overall reaction represented by the following formula (1) or (2): CO2 gas and H2 gas are reactants, and CO gas and H2O gas are products. The products may further include H2 gas or CO2 gas.

[0038] [ka]

[0039] [ka] In formulas (1) and (2), x represents the molar ratio of CO gas to H gas supplied to the gas converter 30. The molar ratio x is greater than 0.00. Generally, the molar ratio corresponds to the volume ratio.

[0040] The gas shifter 30 may simultaneously advance a reaction different from the overall reaction represented by formula (1) or formula (2). Therefore, the gas shifter 30 may be supplied with CO gas and H gas as reactants, and other gases may also be supplied.

[0041] Figure 2 shows an example of a reaction (x=0.5) whose overall reaction is represented by equation (1). In Figure 2, ΔH is the change in enthalpy (kJ / mol). Enthalpy is also called heat content. As is clear from Figure 2, the reaction whose overall reaction is represented by equation (1) or equation (2) is an endothermic reaction. The product of the endothermic reaction (CO gas) potentially contains a greater amount of heat than the reactant of the endothermic reaction (H gas).

[0042] The overall reaction represented by formula (1) or formula (2) includes, for example, at least one of (A) a reverse water gas shift (RWGS) reaction, (B) a combination of a methanation reaction and a dry reforming (DRM) reaction, and (C) a combination of a methanation reaction and a steam reforming (STR) reaction.

[0043] Compared with (B) and (C), (A) can reduce the number of reactions used and simplify the device configuration. On the other hand, (B) and (C) can lower the reaction temperature compared with (A). Incidentally, the reverse shift reaction is expressed by the following formula (3). The methanation reaction is expressed by the following formula (4). The DRM reaction is expressed by the following formula (5). Furthermore, the STR reaction is expressed by the following formula (6).

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047] [ka] Equation (3) shows that the reverse shift reaction is an endothermic reaction. Equation (4) shows that the methanation reaction is an exothermic reaction. Equation (5) shows that the DRM reaction is an endothermic reaction. Equation (6) shows that the STR reaction is an endothermic reaction. The product of the endothermic reaction (CO gas) potentially contains a larger amount of heat than the reactant of the endothermic reaction (H2 gas or CH4 gas). Therefore, burning the product of the endothermic reaction (CO gas) can produce a larger amount of combustion heat than burning the reactant of the endothermic reaction (H2 gas or CH4 gas).

[0048] The gas converter 30 supplies products such as CO gas to the burner 20. The supplied gas contains, for example, CO gas and HO gas (see formulas (1) and (2)). The supplied gas may further contain H gas (see formula (1)) or CO gas (see formula (2)). The supplied gas may also contain both H gas and CO gas.

[0049] The burner 20 combusts the combustible gas containing CO gas generated in the gas shifter 30 and the combustion-supporting gas to form a flame inside the glass melting furnace 10. By burning CO gas, the combustion heat per mole can be improved compared to burning H gas.

[0050] The combustion reaction of CO gas is expressed by the following formula (7), and the combustion reaction of H2 gas is expressed by the following formula (8). Here, the lower heating value is used as the combustion heat of H2 gas.

[0051] [ka]

[0052] [ka] From equations (7) and (8), it can be seen that burning CO gas can improve the heat of combustion per mole compared to burning H2 gas.

[0053] The combustion reaction of the combustible gas and the combustion-supporting gas by the burner 20 is expressed by, for example, the following formula (9) or (10).

[0054] [ka]

[0055] [ka] Equation (9) represents the combustion reaction of the product obtained by equation (1). Meanwhile, equation (10) represents the combustion reaction of the product obtained by equation (2). In equations (9) and (10), x represents the molar ratio of CO gas to H gas supplied to the gas shifter 30. The molar ratio x is greater than 0.00.

[0056] The combustion reaction between the combustible gas and the combustion-supporting gas may include at least the combustion reactions expressed by formulas (9) and (10), and may further include other combustion reactions.

[0057] As described above, the burner 20 burns the combustible gas containing CO gas generated in the gas shifter 30 and the combustion-supporting gas. Therefore, the combustion gas contains not only HO gas but also CO gas. This is also clear from equations (9) and (10). HO gas can be diluted with CO gas, and the HO gas concentration in the furnace atmosphere can be reduced.

[0058] 3 shows examples 1 to 14 of combinations of combustible gas, combustion-supporting gas, HO gas concentration in the combustion gas, and HO gas concentration in the furnace atmosphere. The furnace atmosphere contains, in addition to the combustion gas, gases released from the glass frits when they are melted. Therefore, the HO gas concentration in the furnace atmosphere is lower than the HO gas concentration in the combustion gas.

[0059] As shown in Figure 3, when H2 gas is used instead of CH4 gas as the combustible gas, CO2 gas is not generated, and the HO gas concentration in the furnace atmosphere increases. This is particularly noticeable when pure oxygen gas is used as the combustion-supporting gas. When pure oxygen gas is used, the HO gas concentration in the combustion gas is 100% by volume, and the HO gas concentration in the furnace atmosphere is 88% by volume.

[0060] The HO gas concentration in the furnace atmosphere is mainly determined by the types of combustible gas and combustion-supporting gas, although it also depends on the type of glass raw material. Therefore, in this embodiment, the HO gas concentration in the combustion gas is adopted as a parameter to be controlled.

[0061] The HO gas concentration in the combustion gas is preferably 67% by volume or less. Conventionally, molten glass has been produced by burning CH gas and O gas (pure oxygen gas), and it has been confirmed that if the HO gas concentration in the combustion gas is 67% by volume or less, there are no problems with the quality of the glass product or corrosion of furnace materials.

[0062] The molar ratio x is preferably 0.50 or more so that the HO gas concentration in the combustion gas is 67% by volume or less (see FIG. 3). The HO gas concentration in the combustion gas is more preferably 65% ​​by volume or less. The molar ratio x is more preferably 0.55 or more so that the HO gas concentration in the combustion gas is 65% by volume or less (see FIG. 3).

[0063] The lower limit of the HO gas concentration in the combustion gas is not particularly limited, but from the viewpoint of feasibility, it is preferably 20% by volume or more. In order to make the HO gas concentration in the combustion gas 20% by volume or more, it is preferable that the molar ratio x is 4.00 or less (see FIG. 3).

[0064] It is more preferable that the molar ratio x is 1.00 or less. When the molar ratio x is 1.00 or less, the combustion reaction is expressed by equation (9). On the other hand, when the molar ratio x exceeds 1.00, the combustion reaction is expressed by equation (10). As is clear from equation (10), when the molar ratio x exceeds 1.00, there is (x-1) moles of CO2 gas that does not contribute to combustion. This CO2 gas not only does not generate combustion heat, but also wastes combustion heat. When the molar ratio x is 1.00 or less, the (x-1) moles of CO2 gas that does not contribute to combustion are not wasted and the glass can be efficiently heated with the combustion heat.

[0065] Although a dedicated supply source such as a gas cylinder (not shown) may be used to supply CO2 gas to the gas shifter 30, in this embodiment, a circulation line 50 is used. The circulation line 50 supplies at least a portion of the CO2 gas contained in the combustion gas from the glass melting furnace 10 to the gas shifter 30. At least a portion of the CO2 gas discharged from the glass melting furnace 10 can be used as a reactant in the overall reaction. CO2 gas can be circulated, thereby reducing the amount of CO2 gas emitted.

[0066] A dehydration tank 51 is preferably provided midway along the circulation line 50. The dehydration tank 51 separates H2O gas from CO2 gas by removing H2O gas from the combustion gas. At least a portion of the separated CO2 gas can be used as a reactant for the overall reaction. This can limit the supply of H2O gas to the gas shifter unit 30, thereby reducing the H2O gas concentration in the furnace atmosphere of the glass melting furnace 10. While it is sufficient for the dehydration tank 51 to remove at least a portion of the H2O gas, in this embodiment, it removes substantially all of the H2O gas.

[0067] The glass manufacturing apparatus 1 preferably recovers heat from the combustion gas burned by the burner 20 and uses the recovered heat to promote the overall reaction represented by formula (1) or formula (2). By recovering heat from the combusted combustion gas, energy waste can be reduced. As the heat recovery means, a recuperator or a heat storage chamber, which will be described later, is used. The heat recovery means and the like will be described below.

[0068] A first embodiment of a glass manufacturing apparatus 1 including a recuperator 60 and a reactor 70 will be described with reference to Fig. 4. The glass manufacturing apparatus 1 includes a glass melting furnace 10, a burner 20, the recuperator 60, and the reactor 70. The reactor 70 is an example of a gas shift unit 30, and promotes, for example, a reverse shift reaction. Below, differences from the glass manufacturing apparatus 1 shown in Fig. 1 will be mainly described.

[0069] The recuperator 60 heats the heat transfer medium by heat exchange with the combustion gas discharged from the glass melting furnace 10. The heat transfer medium may be gas or liquid, but since the temperature of the combustion gas is high, the heat transfer medium is preferably gas in order to prevent boiling. The heat transfer medium is preferably air. The recuperator 60 transfers heat between the combustion gas and the heat transfer medium (e.g., air) without mixing them. In FIG. 4, the recuperator 60 is provided outside the glass melting furnace 10, but it may also be provided inside the glass melting furnace 10. One or more recuperators 60 (one in FIG. 4) are provided. The recuperator 60 is thermally connected to the reactor 70 via a heat transport line 80. The heat transport line 80 transports the heat transfer medium from the recuperator 60 to the reactor 70.

[0070] The reactor 70 heats the CO2 gas and H2 gas through heat exchange with the heat medium heated in the recuperator 60, thereby promoting a reverse shift reaction and producing at least CO gas from the CO2 gas and H2 gas. CO2 gas and H2 gas are reactants, and CO gas and H2O gas are products (see formula (3)). The products may further include H2 gas or CO2 gas (see formulas (1) and (2)). The reactor 70 transfers heat between the reactants and products of the reverse shift reaction without mixing them with a heat medium (e.g., air).

[0071] Because the reverse shift reaction is an endothermic reaction, heat can be efficiently recovered from the heat transfer medium, and the heat recovered from the combustion gas can be efficiently utilized. In addition, the product of the endothermic reaction (CO gas) potentially contains a larger amount of heat than the reactant of the endothermic reaction (H gas). Therefore, by burning CO gas, the heat of combustion per mole can be improved compared to burning H gas (see equations (7) and (8)). As a result, the energy consumption rate of molten glass can be reduced. The energy consumption rate is the amount of energy consumed from outside the system to produce one ton of molten glass.

[0072] The reactions occurring in the reactor 70 need only be endothermic reactions overall, and may include reactions other than the reverse shift reaction. Therefore, the reactants and products in the reactor 70 are not particularly limited. The products (i.e., combustible gas) produced in the reactor 70 are supplied to the burner 20 via a first supply line 21. On the other hand, the combustion-supporting gas is supplied to the burner 20 via a second supply line 22.

[0073] The glass manufacturing apparatus 1 preferably includes a circulation line 50. The circulation line 50 supplies at least a portion of the CO2 gas contained in the combustion gas burned by the burner 20 from the glass melting furnace 10 to the reactor 70. At least a portion of the CO2 gas discharged from the glass melting furnace 10 can be used as a reactant for the reverse shift reaction. The CO2 gas can be circulated, thereby reducing the amount of CO2 gas emitted.

[0074] The glass manufacturing apparatus 1 more preferably includes a dehydration tank 51 in the circulation line 50. The dehydration tank 51 separates H2O gas from CO2 gas by removing H2O gas from the combustion gas. The circulation of H2O gas can be restricted while allowing CO2 gas to circulate. H2O gas not only does not generate combustion heat, but also wastefully consumes combustion heat. Restricting the circulation of H2O gas avoids the needless heating of H2O gas that does not contribute to combustion, and allows the glass to be heated efficiently with the combustion heat. Furthermore, restricting the circulation of H2O gas can reduce the H2O gas concentration in the furnace atmosphere. The dehydration tank 51, for example, removes substantially all H2O gas from the combustion gas.

[0075] It is more preferable to provide a desulfurization tank 52 in the circulation line 50. The desulfurization tank 52 removes sulfur-containing gas from the combustion gas. The sulfur contained in the sulfur-containing gas originates from the glass raw materials, for example, from the fining agent. By providing the desulfurization tank 52 in the circulation line 50, the supply of sulfur-containing gas to the reactor 70 can be limited. This allows the reactor 70 to be maintained in a clean state.

[0076] Unlike the heat storage chamber described later, the recuperator 60 and the reactor 70 recover heat from the combustion gas using a heat medium, so that the combustion gas can be restricted from flowing directly into the reactor 70, and the reactor 70 can be maintained in a clean state. Therefore, when the reactor 70 has a metal catalyst, deterioration of the metal catalyst can be suppressed.

[0077] The reactor 70 may contain a metal catalyst. The metal catalyst promotes the reverse shift reaction. The metal catalyst increases the reaction rate of the reverse shift reaction, allowing the reaction to reach equilibrium in a short time. By increasing the reaction rate of the reverse shift reaction, the metal catalyst can also reduce the volume of the reactor 70. As the metal catalyst, copper (Cu) or nickel (Ni) is used. Note that if the reaction rate is sufficiently fast, the metal catalyst may not be necessary.

[0078] A second embodiment of the glass manufacturing apparatus 1 including a recuperator 60 and a reactor 70 will be described with reference to Fig. 5. Differences from the glass manufacturing apparatus 1 shown in Fig. 4 will be mainly described below. As shown in Fig. 5, the glass manufacturing apparatus 1 preferably includes a heat exchanger 23.

[0079] The heat exchanger 23 is provided midway along the second supply line 22 and preheats the combustion-supporting gas (e.g., pure oxygen gas) by heat exchange with a heat medium heated in the recuperator 60. The heat recovered from the combustion gas can be effectively utilized, reducing the energy consumption rate of the molten glass. The heat exchanger 23 transfers heat between the combustion-supporting gas and the heat medium (e.g., air) without mixing them.

[0080] The heat transport line 80 transports the heat transfer medium from the recuperator 60 to the heat exchanger 23. Preferably, the heat transport line 80 transports the heat transfer medium from the recuperator 60 to the reactor 70, and then transports the heat transfer medium from the reactor 70 to the heat exchanger 23. The reactants of the reverse shift reaction can be heated before the combustion-supporting gas is heated, making it easier to secure the heat required to drive the reverse shift reaction.

[0081] A third embodiment of the glass manufacturing apparatus 1 including a recuperator 60 and a reactor 70 will be described with reference to Fig. 6. Differences from the glass manufacturing apparatus 1 shown in Fig. 4 will be mainly described below. As shown in Fig. 6, the glass manufacturing apparatus 1 preferably includes a second heat exchanger 24 and a second dehydration tank 25.

[0082] The second heat exchanger 24 transfers heat from the product of the reactor 70 to the combustion-supporting gas at a first point where the first supply line 21 overlaps with the second supply line 22. The second heat exchanger 24 transfers heat between the product of the reactor 70 and the combustion-supporting gas without mixing them. The second dehydration tank 25 removes HO gas from the product of the reactor 70 at a second point downstream of the first point on the first supply line 21. The second dehydration tank 25 only needs to remove at least a portion of the HO gas, but in this embodiment, it removes substantially all of the HO gas.

[0083] The second dehydration tank 25 removes HO gas from the product of the reactor 70, for example, by cooling the product. HO gas not only does not generate combustion heat, but also wastefully consumes the combustion heat. The second dehydration tank 25 limits the supply of HO gas to the burner 20. This prevents the wasteful heating of HO gas that does not contribute to combustion, allowing the glass to be efficiently heated by the combustion heat. Furthermore, the HO gas concentration in the furnace atmosphere can be reduced.

[0084] Before second dehydration tank 25 cools the product of reactor 70, second heat exchanger 24 transfers heat from the product of reactor 70 to the combustion-supporting gas. This allows efficient use of heat recovered from the combustion gas, reducing the energy consumption rate of the molten glass.

[0085] A first embodiment of a glass manufacturing apparatus 1 including a first heat regenerator 90A and a second heat regenerator 90B will be described with reference to Fig. 7. The glass manufacturing apparatus 1 includes a glass melting furnace 10, a first burner 20A, a second burner 20B, a first heat regenerator 90A, and a second heat regenerator 90B. The first heat regenerator 90A and the second heat regenerator 90B are an example of a gas shift unit 30, and promote, for example, a reverse shift reaction. Below, differences from the glass manufacturing apparatus 1 shown in Fig. 1 will be mainly described.

[0086] The first heat storage chamber 90A and the second heat storage chamber 90B are used in combination with the first burner 20A and the second burner 20B. Although the number of first heat storage chambers 90A is one in Fig. 7, there may be more than one. Similarly, the number of second heat storage chambers 90B, the number of first burners 20A, and the number of second burners 20B may also be one or more.

[0087] In the glass manufacturing apparatus 1, the first burner 20A alternately forms a flame inside the glass melting furnace 10, and the second burner 20B alternately forms a flame inside the glass melting furnace 10. Fig. 7 is a diagram showing a state in which the first burner 20A forms a flame inside the glass melting furnace 10.

[0088] The first regenerator 90A recovers heat from the combustion gas discharged from the glass melting furnace 10 while the second burner 20B forms a flame inside the glass melting furnace 10. The first regenerator 90A releases the previously recovered heat to promote a reverse shift reaction that produces at least CO gas from CO gas and H gas while the first burner 20A forms a flame inside the glass melting furnace 10. The first burner 20A forms a flame inside the glass melting furnace 10 by combusting the combustible gas, including CO gas, and the combustion-supporting gas produced in the first regenerator 90A.

[0089] Similarly, the second regenerator 90B recovers heat from the combustion gas discharged from the glass melting furnace 10 while the first burner 20A forms a flame inside the glass melting furnace 10. The second regenerator 90B releases the previously recovered heat to promote a reverse shift reaction that produces at least CO gas from CO gas and H gas while the second burner 20B forms a flame inside the glass melting furnace 10. The second burner 20B forms a flame inside the glass melting furnace 10 by combusting the combustible gas, including CO gas, and the combustion-supporting gas produced in the second regenerator 90B.

[0090] The combustion gas flows directly into the first regenerator chamber 90A and the second regenerator chamber 90B, unlike the recuperator 60 and the reactor 70. The heat of the combustion gas is accumulated in the hearths of the first regenerator chamber 90A and the second regenerator chamber 90B.

[0091] The first heat storage chamber 90A and the second heat storage chamber 90B heat the CO2 gas and H2 gas to promote a reverse shift reaction, producing at least CO gas from the CO2 gas and H2 gas. CO2 gas and H2 gas are reactants, and CO gas and H2O gas are products (see formula (3)). The products may further include H2 gas or CO2 gas (see formulas (1) and (2)).

[0092] Because the reverse shift reaction is an endothermic reaction, heat can be efficiently recovered from the combustion gas, and the heat of the combustion gas can be efficiently utilized. In addition, the product of the endothermic reaction (CO gas) potentially contains a larger amount of heat than the reactant of the endothermic reaction (H gas). Therefore, by burning CO gas, the heat of combustion per mole can be improved compared to burning H gas (see Equations (7) and (8)). As a result, the energy consumption rate of molten glass can be reduced.

[0093] The reactions occurring in the first heat storage chamber 90A and the second heat storage chamber 90B may be endothermic reactions overall, and may include reactions other than the reverse shift reaction. Therefore, the reactants and products in the first heat storage chamber 90A and the second heat storage chamber 90B are not particularly limited.

[0094] The glass manufacturing apparatus 1 preferably includes a circulation line 50. The circulation line 50 supplies at least a portion of the CO2 gas contained in the combustion gas discharged from the glass melting furnace 10 from the second regenerator 90B to the first regenerator 90A while the first burner 20A forms a flame inside the glass melting furnace 10. At least a portion of the CO2 gas discharged from the glass melting furnace 10 can be used as a reactant for the reverse shift reaction. The CO2 gas can be circulated, thereby reducing the amount of CO2 gas emitted.

[0095] The circulation line 50 may supply at least a portion of the CO2 gas contained in the combustion gas discharged from the glass melting furnace 10 from the first regenerator 90A to the second regenerator 90B while the second burner 20B forms a flame inside the glass melting furnace 10. Note that the circulation line 50 that circulates the CO2 gas while the first burner 20A forms a flame inside the glass melting furnace 10 and the circulation line 50 that circulates the CO2 gas while the second burner 20B forms a flame inside the glass melting furnace 10 are the same in this embodiment, but they may be different lines or may be provided separately.

[0096] The glass manufacturing apparatus 1 more preferably includes a dehydration tank 51 in the circulation line 50. The dehydration tank 51 separates H2O gas from CO2 gas by removing H2O gas from the combustion gas. The circulation of H2O gas can be restricted while allowing CO2 gas to circulate. H2O gas not only does not generate combustion heat, but also wastefully consumes combustion heat. If the circulation of H2O gas can be restricted, the H2O gas that does not contribute to combustion is not unnecessarily heated, and the glass can be efficiently heated by the combustion heat. Furthermore, if the circulation of H2O gas can be restricted, the H2O gas concentration in the furnace atmosphere can be reduced. Although it is sufficient for the dehydration tank 51 to remove at least a portion of the H2O gas, in this embodiment, substantially all of the H2O gas is removed.

[0097] It is more preferable to provide a desulfurization tank 52 in the circulation line 50. The desulfurization tank 52 removes sulfur-containing gas from the combustion gas. The sulfur contained in the sulfur-containing gas originates from the glass raw materials, for example, from a fining agent. By providing the desulfurization tank 52 in the circulation line 50, it is possible to limit the supply of sulfur-containing gas to the first heat storage chamber 90A or the second heat storage chamber 90B.

[0098] The following supplementary notes are disclosed regarding the above-described embodiments. [Appendix 1] The overall reaction is represented by formula (1) or formula (2) described in the specification, and at least CO gas is produced from CO gas and H gas; burning the generated flammable gas containing CO gas and the combustion-supporting gas with a burner to form a flame inside the glass melting furnace; A method for producing glass comprising the steps of: [Appendix 2] 2. The glass manufacturing method according to claim 1, wherein the H2O gas concentration in the combustion gas burned by the burner is 67% by volume or less. [Appendix 3] 3. The method for producing glass according to claim 1, wherein at least a portion of CO2 gas contained in the combustion gas burned by the burner is used as a reactant for the overall reaction. [Appendix 4] H2O gas is removed from the combustion gas burned by the burner to separate H2O gas and CO2 gas, 4. The method for producing glass according to claim 3, wherein at least a portion of the separated CO2 gas is used as a reactant in the overall reaction. [Appendix 5] 5. The method for producing glass according to any one of claims 1 to 4, wherein the molar ratio x of CO2 gas to H2 gas in the overall reaction is greater than 0.00 and not greater than 1.00. [Appendix 6] 6. The method for producing a glass according to any one of Appendices 1 to 5, wherein the overall reaction represented by formula (1) or formula (2) includes at least one of (A) a reverse shift reaction, (B) a combination of a methanation reaction and a dry reforming reaction, and (C) a combination of a methanation reaction and a steam reforming reaction. [Appendix 7] 7. The method for producing glass according to any one of Appendices 1 to 6, wherein heat recovered from combustion gas combusted in the burner is used for the overall reaction represented by formula (1) or formula (2). [Appendix 8] a gas conversion unit that generates at least CO gas from CO gas and H gas by an overall reaction represented by formula (1) or formula (2) described in the specification; a burner that forms a flame inside the glass melting furnace by combusting the flammable gas containing CO gas generated in the gas shifter and a combustion-supporting gas; A glass manufacturing apparatus comprising: [Appendix 9] 9. The glass manufacturing apparatus according to claim 8, wherein the H2O gas concentration in the combustion gas burned by the burner is 67% by volume or less. [Appendix 10] 10. The glass manufacturing apparatus according to claim 8 or 9, further comprising a circulation line for supplying at least a portion of the CO2 gas contained in the combustion gas burned by the burner from the glass melting furnace to the gas converting unit. [Appendix 11] 11. The glass manufacturing apparatus according to claim 10, further comprising a dehydration tank disposed in the circulation line for removing H2O gas from the combustion gas. [Appendix 12] 12. The glass manufacturing apparatus according to any one of claims 8 to 11, wherein the molar ratio x of CO2 gas to H2 gas in the overall reaction is greater than 0.00 and not greater than 1.00. [Appendix 13] 13. The glass manufacturing apparatus according to any one of Appendices 8 to 12, wherein the overall reaction represented by formula (1) or formula (2) includes at least one of (A) a reverse shift reaction, (B) a combination of a methanation reaction and a dry reforming reaction, and (C) a combination of a methanation reaction and a steam reforming reaction. [Appendix 14] 14. The glass manufacturing apparatus according to any one of Appendices 8 to 13, wherein heat recovered from the combustion gas combusted by the burner is used for the overall reaction represented by the formula (1) or the formula (2).

[0099] The glass manufacturing method and glass manufacturing apparatus according to the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments, etc. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These changes also naturally fall within the technical scope of the present disclosure. [Explanation of symbols]

[0100] 1. Glass manufacturing equipment 10 Glass melting furnace 20 Burner 30 Gas transformation section

Claims

1. The overall reaction is represented by the following formula (1) or the following formula (2), ２ Gas and H ２ generating at least CO gas from the gas; burning the generated flammable gas containing CO gas and the combustion-supporting gas with a burner to form a flame inside the glass melting furnace; A method for producing glass comprising the steps of: 【Chemistry 1】 【Chemistry 2】

2. H in the combustion gas burned by the burner ２ 2. The method for producing glass according to claim 1, wherein the O gas concentration is 67% by volume or less.

3. CO contained in the combustion gas burned by the burner ２ 3. The method of claim 1, wherein at least a portion of the gas is used as a reactant in the overall reaction.

4. H from the combustion gas burned by the burner ２ By removing O gas, H ２ O gas and CO ２ Separating the gas, The separated CO ２ 4. The method of claim 3, wherein at least a portion of the gas is used as a reactant in the overall reaction.

5. In the overall reaction, H ２ CO to gas ２ 3. The method for producing glass according to claim 1, wherein the molar ratio x of the gas is greater than 0.00 and not greater than 1.

00.

6. 3. The method for producing a glass according to claim 1 or 2, wherein the overall reaction represented by formula (1) or formula (2) includes at least one of (A) a reverse shift reaction, (B) a combination of a methanation reaction and a dry reforming reaction, and (C) a combination of a methanation reaction and a steam reforming reaction.

7. 3. The method for producing glass according to claim 1 or 2, wherein heat recovered from combustion gas combusted in the burner is used for the overall reaction represented by formula (1) or formula (2).

8. The overall reaction is represented by the following formula (1) or the following formula (2), ２ Gas and H ２ a gas converter that generates at least CO gas from the gas; a burner that forms a flame inside the glass melting furnace by combusting the flammable gas containing CO gas generated in the gas shifter and a combustion-supporting gas; A glass manufacturing apparatus comprising: 【Transformation 3】 【Chemistry 4】

9. H in the combustion gas burned by the burner ２ 9. The glass manufacturing apparatus according to claim 8, wherein the O gas concentration is 67% by volume or less.

10. CO contained in the combustion gas burned by the burner ２ The glass manufacturing apparatus according to claim 8 or 9, further comprising a circulation line that supplies at least a portion of the gas from the glass melting furnace to the gas transformer unit.

11. In the circulation line, H is extracted from the combustion gas. ２ The glass manufacturing apparatus according to claim 10, further comprising a dehydration tank for removing O gas.

12. In the overall reaction, H ２ CO to gas ２ 10. The glass manufacturing apparatus according to claim 8, wherein the molar ratio x of the gas is greater than 0.00 and equal to or less than 1.

00.

13. 10. The glass manufacturing apparatus according to claim 8 or 9, wherein the overall reaction represented by formula (1) or formula (2) includes at least one of (A) a reverse shift reaction, (B) a combination of a methanation reaction and a dry reforming reaction, and (C) a combination of a methanation reaction and a steam reforming reaction.

14. 10. The glass manufacturing apparatus according to claim 8, wherein heat recovered from combustion gas combusted by the burner is used for the overall reaction represented by formula (1) or formula (2).

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