Method for building float glass cooling part pressure relief chimney

Abstract

The invention discloses a method for building a float glass cooling part pressure relief chimney. Comprising the following steps that firstly, a steel structure platform is additionally arranged at a pressure relief opening to support a subsequent chimney and a subsequent flue; secondly, two layers of aluminum silicate heat preservation cotton are laid on a platform at the bottom of the pressure relief chimney for heat insulation treatment; 3, designing the size of a pressure relief opening according to a cooling part of the melting furnace, and building a flue by using clay standard bricks; step 4, chimney design; fifthly, a marking ruler is manufactured or pasted at the upper end of the chimney opening; and 6, sealing the upper part of the flue. After the method is implemented, the pressure of the cooling part can be accurately controlled by adjusting the pavement area of the chimney opening adjusting block. Meanwhile, the scale design of the left and right pressure relief openings accurately achieves left and right symmetrical pressure relief.

Description

Technical Field

[0001] This invention belongs to the field of float glass production equipment. Background Technology

[0002] During the production process, the cooling section of a float glass furnace experiences localized pressure fluctuations due to the interaction between the high-temperature molten glass and the cooling air supplied by the dilution fan. These pressure fluctuations lead to instability in the glass flow and internal stress, resulting in uneven annealing stress in the annealing furnace and causing defects such as optical distortion, thus affecting glass quality. Furthermore, excessive pressure in the cooling section can exacerbate the erosion of refractory materials, significantly reducing the furnace's lifespan. The design of the pressure relief vents in the cooling section provides favorable conditions for stabilizing the furnace pressure.

[0003] Currently, most float glass production lines are designed with two pairs of pressure relief ports symmetrically opened upstream and downstream of the cooling section's breast wall. The size of these ports is controlled by either sealing them with clay bricks or installing stainless steel pressure relief sliding doors. However, these methods carry certain risks. First, the pressure relief ports are directly connected to the breast wall, creating a direct connection between the cooling section's internal space and the external environment. When negative pressure occurs inside the furnace, a large amount of contaminants around the pressure relief ports can be drawn into the furnace, affecting glass quality. Second, this method primarily relies on the pressure difference between the inside and outside of the cooling section for pressure relief, resulting in poor efficiency. Third, the conventional opening size of the pressure relief ports can only be estimated, not accurately determined, making it difficult to achieve symmetrical pressure relief.

[0004] CN200410010366.3 discloses a pressure stabilizing device for the cooling section of a float glass production line melting furnace. A pair of chimneys are set on each side of the cooling section. The air duct at the top of the chimney is connected to a fan. The inner wall of the annular air inlet has multiple air outlets arranged around the circumference. A regulating valve for controlling and adjusting the air inlet volume and a pressure measuring tube for measuring the furnace pressure are installed.

[0005] CN202220635630.6 discloses a pressure regulating device for the cooling section of a float glass melting furnace, including a chimney. One end of the chimney is connected to the cooling section of the melting furnace, and an air curtain is installed between the two ends of the chimney. The air curtain is used to create resistance to the airflow inside the chimney. That is, a draft is formed inside the chimney, which changes with the pressure of the cooling section of the melting furnace. In order to maintain the stability of the furnace pressure, an air curtain is installed between the two ends of the chimney. The air curtain creates resistance to the airflow inside the chimney. This resistance is controllable and stable. When the furnace pressure increases, the amount of gas discharged from the chimney increases, and when it decreases, the amount of gas discharged decreases, thereby automatically maintaining the constant pressure of the cooling section of the melting furnace. The above invention has the following shortcomings: 1. The high-velocity, low-temperature air in the air curtain and the high-temperature exhaust gas in the cooling section produce fluidized matter that condenses into the flue. When the dilution fan trips, there is a negative pressure inside the cooling section of the furnace, which will draw the air from the air curtain into the cooling section, causing the condensate in the flue to be drawn into the cooling section and causing pollution. 2. The air curtain is unstable, isolating most of the exhaust gas from being discharged, affecting the cooling efficiency of the dilution air on the glass. Summary of the Invention

[0006] The main objective of this invention is to provide a method for constructing a pressure relief chimney for the cooling section of float glass.

[0007] The technical solution of the present invention is as follows:

[0008] A method for constructing a pressure relief chimney for the cooling section of float glass includes the following steps:

[0009] Step 1: Add a new steel structure platform at the pressure relief outlet to support the subsequent chimney and flue;

[0010] Step 2: Lay two layers of aluminum silicate insulation cotton on the bottom platform of the pressure relief chimney for heat insulation to prevent deformation of the steel structure; then lay a layer of clay bricks on top of the insulation cotton as the bottom of the flue.

[0011] Step 3: Based on the design size of the pressure relief port of the furnace cooling section, construct the flue using clay bricks. The cross-sectional dimension of the flue gas inlet should be larger than the design pressure relief port of the furnace cooling section; the design position of the chimney opening should be larger than the width of the cooling section arch walkway.

[0012] Step 4, Chimney Size Design

[0013] According to the ideal gas equation PV=nRT, the gas volume V at different temperatures is obtained. 烟 =P 稀 *Q 稀 *24*T 烟 / T 稀 *P 烟 And given the flue gas volume V=Q*h, the actual flue gas volume in the cooling section can be obtained; the formula for the chimney outlet area is: Where Q is the flue gas volume (m3 / h) and Vy is the flue gas velocity (m / s);

[0014] The formula yields the cross-sectional area of ​​the chimney outlet for different flue gas velocities, and the length of the chimney when the width is fixed.

[0015] Step 5: Make or attach a marking ruler at the top of the chimney opening. Use the chimney opening adjustment block to adjust the chimney opening according to the marking ruler, thereby precisely controlling the size of the chimney opening, controlling the flue gas emission from the cooling section, and controlling the pressure of the cooling section.

[0016] Step 6, sealing the upper part of the flue: Use hot filler to seal the brick joints to ensure the airtightness of the flue and reduce the adhesion of condensate.

[0017] Furthermore, in step one, the flue platform is made of steel plate and has supporting feet at the bottom.

[0018] Furthermore, in step three, the width of the flue is greater than the length of the pressure relief port; the height of the flue is greater than the width of the pressure relief port.

[0019] Furthermore, in step five, the thickness of the chimney opening adjustment block is 5~10mm.

[0020] Furthermore, in step five, the chimney opening adjustment block is a zero-expansion silica brick; the zero-expansion silica brick is movable at the upper end of the chimney opening.

[0021] Furthermore, in step five, if it is necessary to adjust the cooling section pressure again according to production needs, the size of the chimney opening is precisely controlled by moving the position of the zero-expansion silica brick at the top of the chimney opening according to the marking ruler.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention enables precise control of the cooling section pressure by adjusting the surface area of ​​the chimney opening regulating block. Simultaneously, the left and right pressure relief port scale design ensures precise symmetrical pressure relief.

[0024] By designing and constructing pressure relief chimneys on both sides of the cooling section of the float glass melting furnace, a draft is generated at the chimney openings to extract flue gas from inside the cooling section. Compared to traditional pressure relief methods, chimney pressure relief adds the auxiliary draft at the chimney openings, significantly improving the discharge of flue gas.

[0025] This invention greatly reduces the contamination of the cooling section caused by negative pressure air entering the cooling section cavity through the original cooling section pressure relief port. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention.

[0027] Figure 2 This is a partial schematic diagram of the present invention.

[0028] Figure 3 This is a top view of the structure of the present invention.

[0029] In the diagram: 1-Cooling section; 2-Pressure relief port; 3-Fluorite duct; 4-Chimney; 5-Fluorite platform

[0030] 6-Insulation cotton 7-Supporting feet 8-Chimney opening adjustment block 9-Chimney opening 10-Scale line Detailed Implementation

[0031] Example 1

[0032] See Figures 1 to 3 In this invention, a flue platform 5 is provided at the left and right pressure relief ports 2 of the cooling section 1. The flue platform 5 is made of steel plate and has supporting feet 7 at the bottom. A chimney 4 and a flue 3 for connecting the chimney 4 and the pressure relief port 2 are provided on the flue platform 5. The top of the chimney 4 is provided with multiple chimney opening adjustment blocks 8 arranged in parallel and scale lines 10. The opening area of ​​the chimney opening 9 is controlled by the arrangement of the chimney opening adjustment blocks 8 and the markings of the scale lines.

[0033] Furthermore, the width of the flue 3 is greater than the length of the pressure relief port 2; the height of the flue 3 is greater than the width of the pressure relief port 2.

[0034] The requirements for the flue arch and chimney opening seal are high, specifically: high resistance to corrosion and acid to prevent brick erosion and falling debris; high thermal stability, remaining intact even at long-term high temperatures of 1300℃ and not breaking during disassembly; and low thermal expansion to fit snugly against the chimney and reduce air permeability. In this invention, the chimney opening adjusting block 8 is made of zero-expansion silica brick, which meets the above conditions. The thickness of the chimney opening adjusting block 8 is preferably 5~10mm.

[0035] Furthermore, hot-applied sealant is used to seal the brick joints, ensuring the flue's airtightness and reducing condensation buildup.

[0036] Furthermore, two layers of aluminum silicate insulation cotton 6 are laid on the bottom platform (steel structure panel) of the pressure relief chimney for heat insulation to prevent deformation of the steel structure. A layer of clay bricks is then laid on top of the insulation cotton 6 as the bottom of the flue.

[0037] The specific bricklaying method of the present invention is as follows:

[0038] Step 1: Steel Structure Platform

[0039] A steel structure platform, 1500mm wide (larger than the pressure relief vent) and 3300mm long, was constructed using 5mm thick iron plates, and reinforced with I-beams. This platform is located at the bottom of the pressure relief chimney in the float glass cooling section.

[0040] Step 2: Laying the bottom of the flue

[0041] Two layers of aluminum silicate insulation cotton are laid on the bottom platform (steel structure panel) of the pressure relief chimney for heat insulation to prevent deformation of the steel structure. A layer of clay bricks is then laid on top of the insulation cotton to form the bottom of the flue.

[0042] Step 3: Construction of the flue

[0043] Based on the design size of the pressure relief vent in the furnace cooling section, the flue was constructed using clay bricks, with the flue gas inlet cross-section larger than the design pressure relief vent in the furnace cooling section. The chimney opening was designed to be larger than the width of the cooling section's arched walkway. This not only prevents the steel structure walkway from being carbonized by the upward-exhausted high-temperature flue gas, but also avoids employees being burned by the heat during inspections.

[0044] Flue design for a 350t / d electronic glass production line:

[0045] The flue length is 3300mm (the length of the steel structure platform); the flue width is 1500mm (greater than the length of the pressure relief port); and the flue height is 600mm (greater than the width of the pressure relief port).

[0046] Step 4: Chimney Size Design

[0047] Chimney outlet cross-sectional area

[0048] Table 1: Operating parameters of the cooling section of a 350t / d electronic glass production line

[0049] <![CDATA[Dilution air (P 稀 ) Pa]]> <![CDATA[Dilution air volume (Q 稀 )(m 3 / h)]]> <![CDATA[Dilution air temperature (T 稀 ) K]]> <![CDATA[Cooling section temperature (T 烟 ) K]]> <![CDATA[Cooling section pressure (P 烟 ) Pa]]> 1027 2000 303 1473 18

[0050] Based on the actual production data shown in the figure above, and according to the ideal gas equation PV=nRT, the gas volume V at different temperatures can be obtained. 烟 =P 稀 *Q 稀 *24*T 烟 / T 稀 *P 烟 =(1027*2000*1473*24) / (18*303)=13313716m 3 Given the flue gas volume V = Q * h, the actual flue gas volume in the cooling section is: Q = 13313716 / 24 = 554738 m³ 3 Formula for chimney outlet area: Where Q is the flue gas volume (m3 / h) and Vy is the flue gas velocity (m / s).

[0051] The formula can be used to obtain the cross-sectional area of ​​the chimney outlet for different flue gas velocities, and the length of the chimney when the width is fixed at 1.1m.

[0052] Table 2. Cross-sectional area of ​​chimney outlet at different flue gas velocities

[0053] <![CDATA[Flue gas flow velocity V y / (m / s)]]> <![CDATA[Chimney outlet area A / (m 2 )]] Chimney width / m Chimney length / m 30 5.14 1.5 3.42 40 3.85 1.5 2.57 50 3.08 1.5 2.05 60 2.57 1.5 1.71 70 2.20 1.5 1.47 80 1.93 1.5 1.28

[0054] By controlling the flue gas velocity at 60 m / s, the chimney outlet area A = 554738 / (3600 * 60) = 2.57 m². 2 Therefore, the length of the chimney is 2.57 / 1.5 = 1.71m.

[0055] Based on the design of a total flue length of 3300mm, the auxiliary chimney should be built starting at a distance of 3300-1710=1590mm from the pressure relief port.

[0056] Chimney height

[0057] Chimney draft formula:

[0058] Where H is the height of the flue (m). External air density (kg / m³) 3 ), Internal smoke density (kg / m³) 3 g is the acceleration due to weight (m / s²) 2 )

[0059] Table 3 Chimney height under different chimney drafts

[0060] Chimney draft / Pa <![CDATA[Air density at standard atmospheric pressure of 303K / (kg / m 3 )]]> <![CDATA[Air density at 1473K and 18Pa / (kg / m 3 )]]> Chimney height / m 5 1.16 0.000043 0.44 10 1.16 0.000043 0.88 15 1.16 0.000043 1.32 20 1.16 0.000043 1.76 25 1.16 0.000043 2.20

[0061] In a specific application, taking the cooling section of a 350t / d electronic glass production line as an example, if the chimney draft is controlled at 15pa, the chimney height can be calculated as H = 15 / ((1.164 - 0.000043) * 9.8) ≈ 1.32m. With an actual cooling section pressure of +18pa and an additional chimney draft of -15pa to assist in flue gas discharge, the actual flue gas pressure discharged from the cooling section is 33pa, which greatly improves flue gas discharge efficiency.

[0062] Step 5: Sealing the flue arch and chimney opening

[0063] The requirements for flue arch and chimney inlet sealing bricks are high, specifically: they must have high resistance to erosion and acid to prevent brick erosion and falling debris; they must have high thermal stability, not cracking even at 1300℃ for a long time, and not breaking during disassembly; they must have low thermal expansion, allowing them to fit snugly against the chimney and reduce air permeability; after experimental investigation, zero-expansion silica bricks meet the requirements, therefore, 5-10mm thick strips of zero-expansion silica bricks can be used for flue arch and chimney inlet sealing bricks.

[0064] By using zero-expansion silica bricks to pave the chimney opening and controlling its size, the emission of flue gas from the cooling section can be controlled, while simultaneously controlling the pressure within the cooling section. Marking rulers can be made or affixed to the chimney to precisely control the size of the exhaust vent. Zero-expansion silica bricks, also known as fused silica bricks or thermal shock resistant silica bricks, are a special siliceous refractory material with an extremely low coefficient of thermal expansion. The silica (SiO2) content of zero-expansion silica bricks is typically greater than 99%, exhibiting excellent resistance to acid erosion. The iron content (Fe2O3) is less than 0.1%, and the flux index (Al2O3 + 2R2O) is less than 0.3%. They also possess good structural stability at high temperatures, with a load softening temperature exceeding 1600°C, making them suitable for high-temperature load-bearing applications.

[0065] Step 6: Sealing the upper part of the flue:

[0066] Use hot-applied sealant to seal the brick joints, ensuring the flue's airtightness and reducing condensation buildup.

[0067] After implementation of this invention, by adjusting the paving area of ​​the zero-expansion silica bricks, the pressure in the cooling section can be precisely controlled at 0.1 Pa (the reading of the on-site pressure transmitter can be controlled at 0.1 Pa). Simultaneously, the scale design of the left and right pressure relief ports ensures precise symmetrical pressure relief.

[0068] By designing and constructing pressure relief chimneys on both sides of the cooling section of the float glass melting furnace, a draft is generated at the chimney openings to extract flue gas from inside the cooling section. Compared to traditional pressure relief methods, chimney pressure relief adds the auxiliary draft at the chimney openings, significantly improving the discharge of flue gas.

[0069] This invention greatly reduces the contamination of the cooling section caused by negative pressure air entering the cooling section cavity through the original cooling section pressure relief port.

[0070] In specific production line applications, the original crude pressure relief method of opening holes in the cooling section of line 1-1 in the "one kiln, two lines" system resulted in a high number of defects (grades 4-5) on the float glass sheets, affecting the selection rate of high-end product orders. After implementing this invention, the number of defects per hour decreased by 50-100.

[0071] This invention significantly reduces the impact of cooling section contamination on plate quality.

[0072] Application Example 1

[0073] In our company's No. 2 float glass production line (700T / D), the steel structure platform of the building cooling section is made of 5mm thick iron plate, with a width of 1100mm (larger than the width of the pressure relief port) and a length of 3300mm. I-beams are used to reinforce and support the platform.

[0074] Bottom platform of the pressure relief chimney (steel structure panel) 3300*1100*5 (length*width*thickness)

[0075] Construct pressure relief chimneys on both sides of the float glass cooling section. The designed pressure relief flue dimensions are (length * width * height): 2300 * 1100 mm * 600 mm. The chimney dimensions, calculated using the above method, are designed as (length * width * height): 920 * 1100 * 880 mm.

[0076] Table 4 Operating parameters of the cooling section of the No. 2 float glass production line (700T / D)

[0077] <![CDATA[Dilution air (P 稀 ) Pa]]> <![CDATA[Dilution air volume (Q 稀 )(m 3 / h)]]> <![CDATA[Dilution air temperature (T 稀 ) K]]> <![CDATA[Cooling section temperature (T 烟 ) K]]> <![CDATA[Cooling section pressure (P 烟 ) Pa]]> 467 1000 303 1423 10

[0078] According to the above formula, Q = (467 * 1000 * 1423 * 24) / (10 * 303 * 24) = 219320m 3 With the flue gas velocity controlled at 60 m / s per hour, the chimney outlet area A = 219320 / (3600 * 60) = 1.02 m². 2 Therefore, the chimney length is 1.02 / 1.1=0.92m, meaning the chimney should be built at a position 1380mm from the flue.

[0079] If the chimney draft is controlled at 15 Pa, the chimney height can be calculated as H = 15 / ((1.164 - 0.000024) * 9.8) ≈ 1.31 m. Where 1.164 kg / m² is the maximum thrust. 3 The density of air at standard atmospheric pressure of 303K is 0.000024 kg / m³. 3 This is the air density at standard atmospheric pressure of 1423K.

[0080] With an actual cooling section pressure of +10 Pa and an additional -15 Pa chimney draft to assist in flue gas discharge, the actual flue gas pressure discharged from the cooling section is 25 Pa, significantly improving flue gas discharge efficiency.

[0081] Application Example 2

[0082] Table 5: Operating parameters of the cooling section of a 350t / d electronic glass production line

[0083] <![CDATA[Dilution air (P 稀 ) Pa]]> <![CDATA[Dilution air volume (Q 稀 )(m 3 / h)]]> <![CDATA[Dilution air temperature (T 稀 ) K]]> <![CDATA[Cooling section temperature (T 烟 ). K]]> <![CDATA[Cooling section pressure (P 烟 ) Pa]]> 1027 2000 303 1473 18

[0084] Based on the actual production data shown in the above figure, and according to the ideal gas equation PV=nRT, the gas volume at different temperatures can be obtained as V_smoke = P_dilute * Q_dilute * 24 * T_smoke / T_dilute * P_smoke = (1027 * 2000 * 1473 * 24) / (18 * 303) = 13313716 m³ 3

[0085] Given the flue gas volume V = Q * h, the actual flue gas volume in the cooling section is: Q = 19970574 / 24 = 554738 m³. 3 / h

[0086] Formula for chimney outlet area: Where Q is the flue gas volume (m³) 3 / h), Vy is the flue gas velocity (m / s).

[0087] For the cooling section of a 350t / d electronic glass production line, with the chimney draft controlled at 15pa, the chimney height is H = 15 / ((1.164 - 0.000043) * 9.8) ≈ 1.32m. With an actual cooling section pressure of +18pa and an additional chimney draft of -15pa to assist in flue gas discharge, the actual flue gas pressure discharged from the cooling section is 33pa, significantly improving flue gas discharge efficiency.

Claims

1. A method for building a pressure relief chimney of a float glass cooling section, comprising the following steps: Step one, adding a steel structure platform at the pressure relief port to support the subsequent chimney and flue; Step two, laying two layers of aluminum silicate insulation cotton on the platform at the bottom of the pressure relief chimney for heat insulation treatment to prevent steel structure deformation; laying a layer of clay bricks above the insulation cotton as the bottom of the flue; Step three, designing the size of the pressure relief port according to the cooling section of the melting furnace, using clay bricks to build the flue, and the cross-sectional size of the flue gas inlet is larger than the design of the pressure relief port of the cooling section of the furnace; the design position of the chimney port is larger than the width of the cooling section; Step four, chimney size design According to the ideal gas equation PV = nRT, the gas volume V at different temperatures is 烟 = P 稀 *Q 稀 *24*T 烟 / T 稀 *P 烟 and the flue gas volume V = Q*h, the actual cooling part flue gas volume; chimney outlet area formula: , where Q is the flue gas volume (m3 / h), Vy is the flue gas flow rate (m / s); According to the formula, the cross-sectional area of the chimney outlet at different flue gas flow rates; and the length of the chimney when the width is fixed; Step five, making or pasting a mark ruler on the upper end of the chimney port, using a chimney opening adjusting block, and controlling the size of the chimney opening according to the mark ruler, to finely control the size of the chimney opening, control the flue gas emission of the cooling section, and control the pressure of the cooling section; Step six, sealing the upper part of the flue: using hot repair material to seal the brick joints to ensure the airtightness of the flue and reduce condensate adhesion.

2. A method of constructing a pressure relief stack for a float glass cooling section according to claim 1, wherein In step one, the flue platform is made of steel plate with supporting feet at the bottom.

3. A method of constructing a pressure relief stack for a float glass cooling section according to claim 1, wherein In step three, the width of the flue is greater than the length of the pressure relief port; the height of the flue is greater than the width of the pressure relief port.

4. A method of constructing a pressure relief stack for a float glass cooling section according to claim 1, wherein In step five, the thickness of the chimney opening adjusting block is 5-10mm.

5. A method of constructing a pressure relief stack for a float glass cooling section according to claim 1, wherein In step five, the chimney opening adjusting block is a zero expansion silica brick; the zero expansion silica brick is movable at the upper end of the chimney port.

6. A method of constructing a pressure relief stack for a float glass cooling section according to claim 5, wherein In step five, if it is necessary to adjust the pressure of the cooling section again according to production needs, the size of the chimney opening can be finely controlled by moving the position of the zero expansion silica brick at the upper end of the chimney port according to the mark ruler.

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