A process for producing high-transmission float glass

Abstract

This application belongs to the field of high-transmittance photovoltaic rolled glass technology, specifically relating to a process for producing high-transmittance photovoltaic rolled glass. The process includes: obtaining raw materials, mixing, melting in a gas furnace, three-row bubbling, defoaming in hot spots, high-temperature clarification, rolling, and annealing to obtain high-transmittance photovoltaic rolled glass. Gas is used as the main fuel, with natural gas and pure oxygen configured at the front end of the gas furnace for combustion assistance. The furnace atmosphere inside the gas furnace is an oxidizing atmosphere, promoting the oxidation of iron ions in the molten glass. This application improves product transmittance and yield, and the gentle temperature field effectively reduces defects caused by insufficient homogenization of the molten glass, increasing the rolled glass yield by 3%-5%.

Description

Technical Field

[0001] This application relates to the field of high-transmittance photovoltaic rolled glass technology, specifically, this application relates to a process for producing high-transmittance photovoltaic rolled glass. Background Technology

[0002] With the continuous decline in the cost of photovoltaic power generation, rolled photovoltaic glass has become the mainstream choice for photovoltaic module substrates due to its advantages of low cost and large size. Currently, most mainstream melting solutions in the industry use natural gas + air-assisted combustion furnaces.

[0003] The existing gas kilns have the following disadvantages: high cost: natural gas prices vary greatly across regions, leading to persistently high fuel costs; difficulty in transformation: considering that gas kilns are weaker than natural gas kilns in controlling the redox atmosphere, they are mostly used for producing ordinary architectural glass, and are not currently used for producing photovoltaic glass. Breaking this convention requires overcoming many technical bottlenecks to ultimately achieve the transformation of gas kilns. The combustion characteristics of existing gas kilns are a relatively strong reducing atmosphere, resulting in an unstable redox atmosphere within the kiln. Affected by this atmosphere, the concentration of ferrous ions in the molten glass is high, affecting the transmittance of the glass between 380-1100nm. The unstable atmosphere leads to unstable ferrous ions, and consequently, unstable transmittance. Therefore, there is an urgent need for a process that uses gas kilns to produce high-transmittance photovoltaic rolled glass. Summary of the Invention

[0004] This application provides a process for producing high-transparency photovoltaic rolled glass, comprising: obtaining raw materials, mixing, melting in a gas kiln, three-row bubbling, defoaming in hot spots, high-temperature clarification, rolling, and annealing to obtain high-transparency photovoltaic rolled glass; wherein the Redox value of the raw materials is +4.0 to +7.0, gas is used as the main fuel, and natural gas + pure oxygen are configured at the front end of the gas kiln for combustion assistance; the volume ratio of gas to natural gas is (80-85):(20-15); the furnace atmosphere inside the gas kiln is an oxidizing atmosphere, the oxidation-reduction potential of the glass melt is +130 to +190mV, which promotes the oxidation of iron ions in the glass melt, and the molar ratio of ferrous ions to total iron in the high-transparency photovoltaic rolled glass is ≤0.1:1.

[0005] As a preferred embodiment of the process for producing high-transmittance photovoltaic rolled glass as described in this application, the raw materials, by mass percentage, include: ultra-low iron silica sand: 58%-60%, dolomite: 14%-16%, calcite: 4%-5%, aluminum hydroxide powder: 1%-1.2%, soda ash: 18.5%-19.5%, sodium sulfate: 0.4%-0.6%, and sodium antimonate pyrophosphate: 0.15%-0.2%; wherein, the iron content in the ultra-low iron silica sand is ≤60ppm, and the titanium oxide content in the ultra-low iron silica sand is ≤200ppm.

[0006] In a preferred embodiment of the process for producing high-transparency photovoltaic rolled glass as described in this application, the gas is producer gas with a calorific value of 1700-1800 kcal / Nm³. 3 The volume ratio of natural gas to pure oxygen is 1:2.1.

[0007] As a preferred embodiment of the process for producing high-transparency photovoltaic rolled glass described in this application, the temperature field of the gas furnace is precisely controlled so that the daily temperature fluctuation of the gas furnace is within ±5℃.

[0008] As a preferred embodiment of the process for producing high-transmittance photovoltaic rolled glass described in this application, when the speed of the calender fluctuates within the range of 300-400 m / h during the calendering process, the gentle temperature gradient characteristics of the gas flame are utilized to balance the lateral temperature difference of the molten glass at the gas kiln outlet by using lateral hanging bricks and edge torches. The lateral temperature difference of the molten glass is ≤20℃, the thickness difference of the molten glass is within ±0.1 mm, and the pattern depth is 30-50 μm.

[0009] As a preferred embodiment of the process for producing high-transmittance photovoltaic rolled glass described in this application, the mixing is carried out under a fully automatic batching system. Plastic wear-resistant liners and wear-resistant polyurethane screens are added at each stage of the fully automatic batching system. The increase in iron in the fully automatic batching system is ≤10ppm, and the iron content in the glass melt is ≤85ppm. The mixing also includes premixing.

[0010] As a preferred embodiment of the process for producing high-transparency photovoltaic rolled glass described in this application, the melting temperature of the gas furnace is 1550-1600℃, the high-temperature clarification temperature is 1430-1480℃, and the rolling forming temperature is 1100-1200℃.

[0011] As a preferred embodiment of the process for producing high-transparency photovoltaic rolled glass described in this application, the excess air coefficient in the gas furnace is as follows: the gas furnace is divided into a flame zone and a clarification zone. The excess air coefficient in the flame zone is 1.1-1.3, and the residual oxygen is 3%-4%. The excess air coefficient in the clarification zone is >1.3, and the residual oxygen is >4%.

[0012] As a preferred embodiment of the process for producing high-transparency photovoltaic rolled glass described in this application, the combustion angle of each small furnace in the gas kiln is optimized to ensure complete combustion of the flame, and the front pool depth and bottom sill design of the gas kiln are increased to stabilize the flow of molten glass at the bottom of the gas kiln.

[0013] As a preferred embodiment of the process for producing high-transmittance photovoltaic rolled glass described in this application, the transmittance of the 2mm high-transmittance photovoltaic rolled glass is ≥92.1%, the yield of the 2mm high-transmittance photovoltaic rolled glass is ≥90%, and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass is ≥95%.

[0014] The beneficial effects of this application are as follows: This application provides a process for producing high-transmittance photovoltaic rolled glass. The process utilizes a gas furnace with an oxygen lance (No. 0) to assist high-temperature melting at the furnace's front end. Three rows of bubbling aid in homogenizing the molten glass. Defoaming technology is employed in hot spots. High-temperature clarification promotes the formation of a mirror-like surface in the clarification section, reducing surface bubbles and concretions. The gas furnace is equipped with advanced temperature control technology and precise control of the oxidation-reduction atmosphere, which is conducive to the formation of ferric iron in the molten glass and reduces the proportion of ferrous iron. High-temperature melting combined with an oxidizing atmosphere within the furnace contributes to improved transmittance. An ultra-wide 5.350-meter rolling mill is used for the process. High-transmittance photovoltaic rolled glass is obtained by calendering and annealing. This application uses coal gas as the main fuel and natural gas + pure oxygen are configured at the front end of the coal gas kiln for combustion assistance. The volume ratio of coal gas to natural gas is (80-85):(20-15). The atmosphere in the furnace of the coal gas kiln is an oxidizing atmosphere. The oxidation-reduction potential of the glass melt promotes the oxidation of iron ions in the glass melt. The temperature field of the coal gas kiln is precisely controlled so that the daily temperature fluctuation of the coal gas kiln is within ±5℃. The gentle temperature gradient characteristics of the coal gas flame are used to match the rhythm of high-temperature clarification and calendering of the glass melt.

[0015] This application utilizes sodium pyroantimonate to assist in oxidation and clarification; it employs ultra-low iron silica sand (iron content below 60 ppm) with ultra-low titanium oxide (below 200 ppm) to facilitate the production of high-transmittance photovoltaic rolled glass; the Redox value of the raw materials in this application is +4.0 to +7.0, and the furnace atmosphere in the gas kiln is an oxidizing atmosphere. The gas kiln is divided into a flame zone and a clarification zone. The excess air coefficient in the flame zone is 1.1-1.3, and the residual oxygen is 3%-4%; the excess air coefficient in the clarification zone is >1.3, and the residual oxygen is >4%; the oxidation-reduction potential of the glass melt is +130 to +190 mV; the molar ratio of ferrous ions to total iron in the high-transmittance photovoltaic rolled glass is ≤0.1:1; and the transmittance of 2mm high-transmittance photovoltaic rolled glass is ≥92.1%.

[0016] This application optimizes the combustion angle of each small furnace to ensure complete flame combustion, increases the depth of the front pool of the gas kiln, and enhances the design of the bottom sill of the gas kiln to stabilize the bottom glass melt flow. Defoaming technology is added to the hot spot area to facilitate heat absorption, increase the defoaming speed, and improve the yield of high-quality glass sheets. This application also increases the width of the calender, resulting in wider production sheets, more diverse product specifications, reduced edge loss, increased cutting rate, and a calendering yield of over 90%. With increased production, glass consumption per unit decreases, and the fuel cost per ton of glass is reduced by 5%-10% compared to a natural gas kiln of the same scale. The optimized gas kiln combustion process increases the temperature in the refining zone, significantly reducing glass sheet bubble defects and improving the yield of high-quality finished products to over 95%.

[0017] This application has the following characteristics: significant cost reduction and efficiency improvement, with fuel costs reduced by 5%-10%, greatly increasing enterprise profit margins. It improves product transmittance and yield; the gentle temperature field effectively reduces defects caused by insufficient homogenization of the molten glass, increasing the rolled product yield by 3%-5%. It offers strong production stability and a wide load adjustment range, adapting to the characteristics of rapid order fluctuations and frequent specification changes in the photovoltaic industry. Detailed Implementation

[0018] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] This application provides a process for producing high-transparency photovoltaic rolled glass, comprising: obtaining raw materials, mixing, melting in a gas kiln, three-row bubbling, defoaming in hot spots, high-temperature clarification, rolling, and annealing to obtain high-transparency photovoltaic rolled glass; wherein the Redox value of the raw materials is +4.0 to +7.0, gas is used as the main fuel, and natural gas + pure oxygen are configured at the front end of the gas kiln for combustion assistance; the volume ratio of gas to natural gas is (80-85):(20-15); the furnace atmosphere inside the gas kiln is an oxidizing atmosphere, the oxidation-reduction potential of the glass melt is +130 to +190mV, which promotes the oxidation of iron ions in the glass melt, and the molar ratio of ferrous ions to total iron in the high-transparency photovoltaic rolled glass is ≤0.1:1.

[0020] The raw materials, by mass percentage, include: ultra-low iron silica sand: 58%-60%, dolomite: 14%-16%, calcite: 4%-5%, aluminum hydroxide powder: 1%-1.2%, soda ash: 18.5%-19.5%, sodium sulfate: 0.4%-0.6%, and sodium pyroantimonate: 0.15%-0.2%; wherein, the iron content in the ultra-low iron silica sand is ≤60ppm, and the titanium oxide content in the ultra-low iron silica sand is ≤200ppm.

[0021] The gas is producer gas, and its calorific value is 1700-1800 kcal / Nm³. 3The volume ratio of natural gas to pure oxygen is 1:2.1. The temperature field of the gas kiln is precisely controlled to keep the daily temperature fluctuation within ±5℃. When the calender speed fluctuates within the range of 300-400 m / h during calendering, the gentle temperature gradient characteristics of the gas flame are utilized to balance the lateral temperature difference of the molten glass at the gas kiln outlet through horizontal hanging bricks and side torches. The lateral temperature difference of the molten glass is ≤20℃, the thickness difference is within ±0.1 mm, and the pattern depth is 30-50 μm. The mixing is carried out under a fully automatic batching system. Wear-resistant plastic liners and wear-resistant polyurethane screens are installed at each stage of the fully automatic batching system. The increase in iron in the fully automatic batching system is ≤10 ppm, and the iron content in the molten glass is ≤85 ppm. The mixing also includes premixing.

[0022] The melting temperature in the gas furnace is 1550-1600℃, the high-temperature clarification temperature is 1430-1480℃, and the rolling forming temperature is 1100-1200℃. The furnace atmosphere inside the gas furnace is an oxidizing atmosphere. The gas furnace is divided into a flame zone and a clarification zone. The excess air coefficient in the flame zone is 1.1-1.3, and the residual oxygen is 3%-4%; the excess air coefficient in the clarification zone is >1.3, and the residual oxygen is >4%. The combustion angle of each small furnace in the gas furnace is optimized to ensure complete combustion. The front pool depth and bottom sill design of the gas furnace are increased to ensure stable glass flow at the bottom of the gas furnace. The transmittance of the 2mm high-transmittance photovoltaic rolled glass is ≥92.1%, the yield of the 2mm high-transmittance photovoltaic rolled glass is ≥90%, and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass is ≥95%.

[0023] The technical solution of this application will be further described below with reference to specific embodiments.

[0024] Example 1

[0025] The process involves obtaining raw materials, mixing, melting in a gas kiln, three-row bubbling, defoaming in hot spots, high-temperature clarification, calendering, and annealing to obtain 2mm high-transparency photovoltaic rolled glass. The raw materials, by mass percentage, include: ultra-low iron silica sand: 59.72%, dolomite: 15%, calcite: 4.5%, aluminum hydroxide powder: 1.1%, soda ash: 19%, sodium sulfate: 0.5%, and sodium pyroantimonate: 0.18%. The iron content in the ultra-low iron silica sand is ≤60ppm, and the titanium oxide content in the ultra-low iron silica sand is ≤200ppm. The Redox value of the raw materials is +4.5.

[0026] Mixing is carried out under a fully automatic batching system. Plastic wear-resistant liners and wear-resistant polyurethane screens are installed at each stage of the fully automatic batching system. The increase in iron in the fully automatic batching system is ≤10ppm, and the iron content in the glass melt is ≤85ppm. Mixing also includes premixing.

[0027] Coal gas is used as the main fuel, with natural gas and pure oxygen added at the front end of the gasifier for combustion aiding. The volume ratio of coal gas to natural gas is 82:18. The coal gas is producer gas with a calorific value of 1750 kcal / Nm³. 3 The volume ratio of natural gas to pure oxygen is 1:2.1.

[0028] The temperature field of the gasifier is precisely controlled to keep the daily temperature fluctuation within ±5℃. The furnace atmosphere is oxidizing, and the gasifier is divided into a flame zone and a clarification zone. The excess air coefficient in the flame zone is 1.20, and the residual oxygen is 3.5%; the excess air coefficient in the clarification zone is 1.40, and the residual oxygen is 6.0%. The oxidation-reduction potential of the molten glass is +145mV, which promotes the oxidation of iron ions in the molten glass. The molar ratio of ferrous ions to total iron in 2mm high-transmittance photovoltaic rolled glass is 0.09:1.

[0029] When the speed of the calender fluctuates within the range of 300-400m / h during calendering, the gentle temperature gradient characteristics of the gas flame are utilized to balance the lateral temperature difference of the molten glass at the gas kiln outlet by using lateral hanging bricks and side torches. The lateral temperature difference of the molten glass is ≤20℃, the thickness difference of the molten glass is within ±0.1mm, and the pattern depth is 30-50μm.

[0030] The melting temperature in the gas furnace is 1580℃, the high-temperature clarification temperature is 1450℃, and the rolling forming temperature is 1150℃. The combustion angles of each small furnace within the gas furnace are optimized to ensure complete combustion. The design of the front pool depth and the bottom sill of the gas furnace are also improved to ensure stable flow of molten glass at the bottom of the furnace.

[0031] Tests showed that the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.18%, the yield of the 2mm high-transmittance photovoltaic rolled glass was 91.8%, and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 97%.

[0032] Example 2

[0033] The difference between this embodiment and Embodiment 1 is that, by mass percentage, the raw materials include: ultra-low iron silica sand: 59.65%, dolomite: 14.98%, calcite: 4.49%, aluminum hydroxide powder: 1.1%, soda ash: 18.98%, sodium sulfate: 0.6%, and sodium antimonate pyrophosphate: 0.2%; the Redox value of the raw materials is +6.5, and the volume ratio of coal gas to natural gas is 85:15; the coal gas is producer gas with a calorific value of 1780 kcal / Nm³. 3The excess air coefficient in the flame zone is 1.24, and the residual oxygen is 4%; the excess air coefficient in the refining zone is 1.38, and the residual oxygen is 5.8%. The redox potential of the molten glass is +185mV, which promotes the oxidation of iron ions in the molten glass. The molar ratio of ferrous ions to total iron in 2mm high-transmittance photovoltaic rolled glass is 0.05:1. The melting temperature in the gas furnace is 1600℃, the high-temperature refining temperature is 1480℃, and the rolling forming temperature is 1200℃.

[0034] Tests showed that the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.20%, the yield of the 2mm high-transmittance photovoltaic rolled glass was 90.5%, and the excellent rate of the 2mm high-transmittance photovoltaic rolled glass finished products was 95%.

[0035] Example 3

[0036] The difference between this embodiment and Embodiment 1 is that, by mass percentage, the raw materials include: ultra-low iron silica sand: 59.68%, dolomite: 14.99%, calcite: 4.5%, aluminum hydroxide powder: 1.1%, soda ash: 18.99%, sodium sulfate: 0.55%, and sodium antimonate pyrophosphate: 0.19%; the Redox value of the raw materials is +6.2, and the volume ratio of coal gas to natural gas is 80:20; the coal gas is producer gas with a calorific value of 1800 kcal / Nm³. 3 The excess air coefficient in the flame zone is 1.17, and the residual oxygen is 3%; the excess air coefficient in the refining zone is 1.35, and the residual oxygen is 5.5%. The redox potential of the molten glass is +140mV, which promotes the oxidation of iron ions in the molten glass. The molar ratio of ferrous ions to total iron in 2mm high-transmittance photovoltaic rolled glass is 0.08:1. The melting temperature in the gas furnace is 1550℃, the high-temperature refining temperature is 1430℃, and the rolling forming temperature is 1100℃.

[0037] Tests showed that the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.14%, the yield of the 2mm high-transmittance photovoltaic rolled glass was 91%, and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 96%.

[0038] Comparative Example 1 The difference between this comparative example and Example 1 is that the volume ratio of coal gas to natural gas is 90:10.

[0039] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.15:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 91.98%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 84%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 89%.

[0040] Comparative Example 2 The difference between this comparative example and Example 1 is that the volume ratio of coal gas to natural gas is 75:25.

[0041] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.09:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.12%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 85%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 91%.

[0042] Comparative Example 3 The difference between this comparative example and Example 1 is that, by mass percentage, the raw materials include: ultra-low iron silica sand: 59.72%, dolomite: 15%, calcite: 4.5%, aluminum hydroxide powder: 1.1%, soda ash: 18.28%, sodium sulfate: 1%, sodium pyroantimonate: 0.4%; and the Redox value of the raw materials is +10.

[0043] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.05:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.15%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 83%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 88%.

[0044] Comparative Example 4 The difference between this comparative example and Example 1 is that, by mass percentage, the raw materials include: ultra-low iron silica sand: 59.72%, dolomite: 15%, calcite: 4.5%, aluminum hydroxide powder: 1.1%, soda ash: 19.28%, sodium sulfate: 0.3%, sodium pyroantimonate: 0.1%; and the Redox value of the raw materials is +2.

[0045] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.15:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 91.99%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 86%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 91%.

[0046] Comparative Example 5 The difference between this comparative example and Example 1 is that the excess air coefficient in the flame zone is 1.05 and the residual oxygen is 2%.

[0047] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.12:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.05%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 85.5%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 90%.

[0048] Comparative Example 6 The difference between this comparative example and Example 1 is that the excess air coefficient in the flame zone is 1.35 and the residual oxygen is 5%.

[0049] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.06:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.16%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 87%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 93%.

[0050] Comparative Example 7 The difference between this comparative example and Example 1 is that the redox potential of the glass melt is +110mV.

[0051] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.11:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.08%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 88%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 94%.

[0052] Comparative Example 8 The difference between this comparative example and Example 1 is that the redox potential of the glass melt is +210mV.

[0053] Tests showed that the molar ratio of ferrous ions to total iron in the 2mm high-transmittance photovoltaic rolled glass was 0.08:1; the transmittance of the 2mm high-transmittance photovoltaic rolled glass was 92.17%; the yield of the 2mm high-transmittance photovoltaic rolled glass was 88.5%; and the excellent rate of the finished 2mm high-transmittance photovoltaic rolled glass was 94%.

[0054] Based on the above embodiments and comparative examples, Example 1, combined with Comparative Example 1, shows that an increased proportion of coal gas and natural gas is detrimental to reducing ferrous ions in the glass, thus hindering the production of high-transmittance photovoltaic rolled glass. Example 1, combined with Comparative Example 2, shows that an increased proportion of natural gas leads to excessively high temperatures at the furnace front end, which is detrimental to the recirculation of raw materials and the reduction of surface stones / bubbles. Example 1, combined with Comparative Example 3, shows that excessively high Redox content in raw materials exacerbates refractory material erosion, hindering the healthy operation of the kiln and increasing nitrogen oxides in the exhaust gas, which is detrimental to meeting environmental standards. Example 1, combined with Comparative Example 4, shows that excessively low Redox content in raw materials indicates a strong reducing atmosphere inside the kiln, resulting in increased ferrous ions, causing the glass to turn green, and affecting the production of high-transmittance photovoltaic rolled glass. Performance indicators: Example 1, combined with Comparative Example 5, shows that a low excess air coefficient in the flame zone is not conducive to reducing ferrous ions in the molten glass, resulting in a greenish glass color and affecting the production indicators of high-transmittance photovoltaic rolled glass; Example 1, combined with Comparative Example 6, shows that a high excess air coefficient in the flame zone will lead to a waste of fuel calorific value, while also exacerbating the erosion of refractory materials, resulting in higher levels of nitrogen oxides in the flue gas and more stones on the plate surface; Example 1, combined with Comparative Example 7, shows that a low redox potential in the molten glass is not conducive to reducing ferrous ions, affecting the performance of antimony-based clarifying agents, slowing the oxygen release process, and affecting the clarification and defoaming effect; Example 1, combined with Comparative Example 8, shows that a high redox potential in the molten glass exacerbates the erosion of refractory materials, resulting in higher levels of nitrogen oxides in the flue gas and more stones on the plate surface.

[0055] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A process for producing high-transmittance photovoltaic rolled glass, characterized in that, include: The process involves obtaining raw materials, mixing, melting in a gas kiln, three-row bubbling, defoaming in hot spots, high-temperature clarification, rolling, and annealing to obtain high-transmittance photovoltaic rolled glass. The raw materials, by weight percentage, include: ultra-low iron silica sand: 58%-60%, dolomite: 14%-16%, calcite: 4%-5%, aluminum hydroxide powder: 1%-1.2%, soda ash: 18.5%-19.5%, sodium sulfate: 0.4%-0.6%, and sodium antimonate pyroximate: 0.15%-0.2%. %; the Redox value of the raw materials is +4.0 to +7.0, coal gas is used as the main fuel, and natural gas + pure oxygen is configured at the front end of the coal gas kiln for combustion assistance; the volume ratio of coal gas to natural gas is (80-85):(20-15); the furnace atmosphere inside the coal gas kiln is an oxidizing atmosphere, and the oxidation-reduction potential of the glass melt is +130 to +190mV, which promotes the oxidation of iron ions in the glass melt, and the molar ratio of ferrous ions to total iron in the high-transmittance photovoltaic rolled glass is ≤0.1:

1.

2. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The iron content in the ultra-low iron silica sand is ≤60ppm, and the titanium oxide content in the ultra-low iron silica sand is ≤200ppm.

3. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The gas is producer gas, and its calorific value is 1700-1800 kcal / Nm³. 3 The volume ratio of natural gas to pure oxygen is 1:2.

1.

4. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The temperature field of the gas kiln is precisely controlled to keep the daily temperature fluctuation within ±5℃.

5. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, When the speed of the calender fluctuates within the range of 300-400m / h during calendering, the gentle temperature gradient characteristics of the gas flame are utilized to balance the lateral temperature difference of the molten glass at the gas kiln outlet by using lateral hanging bricks and side torches. The lateral temperature difference of the molten glass is ≤20℃, the thickness difference of the molten glass is within ±0.1mm, and the pattern depth is 30-50μm.

6. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The mixing is carried out under a fully automatic batching system. Plastic wear-resistant liners and wear-resistant polyurethane screens are installed at each stage of the fully automatic batching system. The increase in iron in the fully automatic batching system is ≤10ppm, and the iron content in the glass melt is ≤85ppm. The mixing also includes premixing.

7. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The melting temperature in the gas kiln is 1550-1600℃, the high-temperature clarification temperature is 1430-1480℃, and the calendering temperature is 1100-1200℃.

8. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The furnace atmosphere inside the gas kiln is an oxidizing atmosphere. The gas kiln is divided into a flame zone and a clarification zone. The excess air coefficient in the flame zone is 1.1-1.3, and the residual oxygen is 3%-4%. The excess air coefficient in the clarification zone is >1.3, and the residual oxygen is >4%.

9. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, Optimize the combustion angle of each small furnace in the gas kiln to ensure complete combustion of the flame, increase the front pool depth design and the bottom sill design of the gas kiln to stabilize the flow of molten glass at the bottom of the gas kiln.

10. The process for producing high-transmittance photovoltaic rolled glass according to claim 1, characterized in that, The transmittance of 2mm high-transmittance photovoltaic rolled glass is ≥92.1%, the yield of 2mm high-transmittance photovoltaic rolled glass is ≥90%, and the excellent rate of 2mm high-transmittance photovoltaic rolled glass products is ≥95%.