Tertiary air flashboard with ventilation cooling function for cement kiln

Abstract

The utility model discloses a tertiary air flashboard with a ventilation cooling function for a cement kiln. The tertiary air flashboard is provided with a plate-shaped heat-resistant metal component serving as a framework. The plate-shaped heat-resistant metal component is of a hollow structure; a refractory material brick wall is mounted on the outer side wall surface of the plate-shaped heat-resistant metal component; an unshaped refractory material with a low heat conductivity coefficient is filled between the refractory material brick wall and the outer side wall surface of the plate-shaped heat-resistant metal component; the refractory material brick wall is composed of a plurality of refractory material hanging bricks hung on the outer side wall face of the plate-shaped heat-resisting metal component. And a high-wear-resistance unshaped refractory material is filled between every two adjacent refractory material hanging bricks. The tertiary air flashboard of the rotary cement kiln has excellent wear resistance and scouring resistance, the service life can exceed two years, the tertiary air flashboard is free of maintenance in the using process, the production reliability is improved, and the maintenance and production cost is remarkably reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of cement production process equipment, in particular to a high wear-resistant and long-life tertiary air damper for a dry-process cement kiln. Background Art

[0002] The air volume distribution of a new dry-process cement rotary kiln and a decomposition furnace is realized by adjusting the opening of the tertiary air damper of the kiln tail throat and the high-temperature regulating valve of the tertiary air duct. As the core component of the high-temperature regulating valve, the tertiary air damper (also known as the tertiary air duct damper) plays an important role in cement production. Adjusting the opening of the tertiary air damper can control the air volume distribution of the cement rotary kiln and the decomposition furnace, which has an important impact on the operation rate, energy consumption and clinker quality of the cement kiln. Therefore, the life and reliability of the tertiary air damper are very important for cement production.

[0003] A large amount of fine granular solid clinker particles are mixed in the tertiary air, which contain erosion medium components such as sulfur and alkali. The air temperature can sometimes reach 1050°C, and the wind speed is as high as 20-30 m / s. The high-speed hot air mixed with solid particles causes serious impact, wear and chemical erosion on the damper. At present, the tertiary air damper is generally composed of a steel bar skeleton and refractory castable. During use, the refractory castable on the damper will gradually peel off. Generally, the refractory castable on the working surface needs to be repaired every about half a year, and the whole damper needs to be replaced every 2-3 years. The tertiary air damper weighs 3-5 tons. The maintenance of the tertiary air damper is time-consuming and laborious, and the replacement cost is high and the time consumption is long, which seriously affects the smooth production. There are a large number of dry-process cement kiln production lines in China. The development and use of high-reliability, long-life and maintenance-free tertiary air dampers have important practical significance. Summary of the Utility Model

[0004] The utility model provides a high wear-resistant and long-life tertiary air damper for a dry-process cement kiln. The damper has excellent impact resistance, wear resistance and corrosion resistance. The service life exceeds 1.5 years, and it is maintenance-free during use, effectively avoiding the risks and cost increase caused by uncertain maintenance, and significantly improving the reliability of production. The specific technical solution of the utility model is as follows:

[0005] A tertiary air damper for a cement kiln with a ventilation and cooling function, the tertiary air damper has a plate-shaped heat-resistant metal component as a skeleton; the plate-shaped heat-resistant metal component is a hollow structure; a refractory brick wall is installed on the outer side wall surface of the plate-shaped heat-resistant metal component; an amorphous refractory material with a low thermal conductivity is filled between the refractory brick wall and the outer side wall surface of the plate-shaped heat-resistant metal component; the refractory brick wall is composed of multiple refractory hanging bricks suspended on the outer side wall surface of the plate-shaped heat-resistant metal component; a high wear-resistant amorphous refractory material is filled between every two adjacent refractory hanging bricks.

[0006] The hollow cavity of the plate-shaped heat-resistant metal member is partitioned into a plurality of vertical channels, and the plurality of vertical channels communicate with each other; a lifting hook is installed on the upper part of the plate-shaped heat-resistant metal member, and an air inlet and an air outlet are provided.

[0007] The refractory hanging bricks are fixed to the outer surface of the plate-shaped heat-resistant metal member by metal bolts and nuts.

[0008] The metal bolts are vertically fixed to the outer surface of the plate-shaped heat-resistant metal member by welding or threading, and the diameter of the metal bolts is ≤ 25 mm.

[0009] Each refractory hanging brick contains 1 to 3 stepped straight through-holes, and the length, width and thickness of the hanging brick are ≤ 400 mm and ≤ 80 mm respectively.

[0010] The hot air temperature at the air outlet of the plate-shaped heat-resistant metal member is controlled to be ≤ 400 °C.

[0011] The hot air temperature at the air outlet of the plate-shaped heat-resistant metal member is 150 - 300 °C.

[0012] A kind of tertiary air damper for cement kiln with ventilation and cooling function proposed by the utility model is composed of metal and refractory materials, and includes: ① a large-area plate-shaped hollow metal member, which is the main body skeleton of the damper, and the outer surface is coated with refractory materials. Under the condition that the refractory materials are not damaged, all the metal materials on the metal member do not directly contact with the hot air in the tertiary air duct; ② refractory hanging bricks paved on the outer surface of the hollow metal member, which are high-abrasion-resistant shaped refractory products, and are fixed to the outer surface of the hollow metal member by metal bolts and nuts, and directly contact with the hot air in the tertiary air duct; ③ heat-resistant metal bolts and nuts for fixing the hanging bricks on the metal member, the bolts are vertically welded or vertically fixed to the outer surface of the metal member by threading; the hanging bricks are hung on the bolts and then fixed in position with nuts; ④ low-thermal-conductivity refractory materials for filling the gaps between the hanging bricks and the outer surface of the hollow metal member, with a refractory material thickness of 2 - 10 mm, to prevent hot air from leaking in and directly contacting the outer surface of the metal member, and to protect the metal member from direct corrosion by hot air, and the material is preferably refractory mortar; ⑤ high-abrasion-resistant refractory materials for filling the gaps between the hanging bricks, and the large-area working surface composed of multiple hanging bricks forms a hole-free and integrally dense working surface under the filling action of the refractory materials, eliminating the possibility of hot air entering from the brick joints and directly corroding the metal inside; ⑥ wear-resistant refractory materials filled in the positioning through-holes of the hanging bricks, which block the direct contact between the hot air and the bolts and nuts, reduce the working temperature of the bolts and nuts, and this material can be refractory ramming material or ceramic nuts.

[0013] In this utility model, the integral plate-shaped hollow metal component is the main framework of the gate frame. Its outer surface is entirely coated with refractory materials, and the middle part is a hollow cavity. The cavity is partitioned, and the air inlets and outlets are arranged at the upper part. The rest of the surfaces are airtight sealing structures. The fan passes cooling air into the hollow cavity from the upper air inlet. After the cooling air is heated, it is discharged from the upper air outlet through the interlayer in the hollow cavity. The function of the cooling air is to keep the working temperature of the hollow metal component, positioning bolts and nuts within their safe operating temperature ranges, avoid overheating, and achieve the purpose of improving the reliability and service life of the metal component. If there is no ventilation, the service life of the gate will be reduced, but short-term lack of ventilation has a relatively small impact on the gate's life. The ventilation volume is determined according to the gate area, thickness, temperature and flow rate of the tertiary air, etc. The inlet air is at room temperature, and the hot air temperature at the outlet is controlled to be ≤400 °C, preferably 150 - 300 °C. The metal component serving as the main body of the gate is made of heat-resistant metal, and steels such as Q235b, Q355b, 304, 309S, 310, 310S, 316, etc. can be selected, with 310 stainless steel being preferred.

[0014] The hanging bricks are paved and fixed on the outer surface of the above-mentioned metal component, and the hanging bricks are in direct contact with the hot air in the tertiary air duct. The hanging bricks are wear-resistant shaped refractory products, and materials such as silicon carbide dense shaped products, alumina products, alumina-silica sintered products, etc. can be selected; the length and width of the hanging bricks are ≤400 mm, and the thickness is ≤80 mm. The hanging bricks are provided with through holes perpendicular to the brick surface and parallel to the thickness direction. Each hanging brick has 1 - 3 stepped through holes. The positioning of the hanging bricks is jointly achieved by metal bolts, nuts and refractory mortar. The materials of the metal bolts and nuts can be stainless steels such as 304, 309S, 310, 310S, 316, etc., with 310S being preferred. During installation, first vertically fix the bolts on the outer surface of the metal component by welding or threading. After aligning the through holes of the hanging bricks with the bolt positions, hang the hanging bricks on the bolts, and then fix the hanging bricks with nuts. There is a gap of 2 - 10 mm between the hanging bricks and the surface of the metal component, and the gap is filled with refractory mortar with a low thermal conductivity. The refractory mortar in this gap can be made of refractory materials with relatively small thermal conductivities such as alumina and silica. After drying, the refractory mortar has high strength, can completely fill and compact the gap between the hanging bricks and the metal component, realize the firm fixation of the hanging bricks, and at the same time prevent the hot air in the tertiary air duct from entering the gap and directly acting on the metal component, completely avoiding the thermal corrosion of the metal component by the hot air. The nut is located inside the through hole of the hanging brick, and there is a certain space between the nut and the working surface of the hanging brick. This space is filled with highly wear-resistant refractory materials, and materials such as silicon carbide, alumina, silicon carbide-alumina, etc. various dense ramming materials can be selected, or shaped refractory materials such as silicon carbide, alumina, silicon carbide-alumina, alumina-silica, etc. that have been sintered at high temperatures can also be selected.

[0015] After the refractory bricks are paved on the metal component, there is a gap between the refractory bricks, and the width of the gap is 2-10 mm. After filling with refractory materials, it is equivalent to forming a refractory mud buffer layer between the refractory bricks and the hollow plate-shaped metal component, which can avoid the cracking of the refractory bricks caused by the large difference in the thermal expansion coefficients of the metal and the refractory materials. After the paving of the refractory bricks is completed, the gaps between the refractory bricks are filled with high-abrasion-resistant refractory materials. The materials can be selected from ramming materials or plastic materials of different materials such as silicon carbide-based, alumina-based, and silicon carbide-alumina-based. Silicon carbide-alumina-based ramming material is preferred. After the gaps between the refractory bricks are completely filled, multiple hanging plates form an integral working surface without holes, and the plate-shaped hollow metal component serving as the main skeleton of the gate plate is completely covered by refractory materials with excellent high-temperature performance, avoiding the direct corrosion of the surface of the metal component by high-temperature hot air.

[0016] The gate plate of the present utility model is composed of a composite of metal materials and refractory materials. All the parts in direct contact with the hot air are high-abrasion-resistant and corrosion-resistant refractory materials, and the entire frame body is made of metal. Through the structural design and use of the ventilation function, it is ensured that the metal materials are completely within the safe operating temperature during use, eliminating the hidden danger of over-temperature causing metal deformation and then causing the cracking and spalling of the refractory materials, realizing the long life and high reliability of the tertiary air gate plate. Under normal operating conditions, it can be free of maintenance for 2 years, which can save a large amount of maintenance costs for cement production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the front view of the tertiary air gate plate for a cement kiln with ventilation and cooling functions. (In the figure, a refractory brick and a metal screw in the upper left corner are removed, and the amorphous refractory materials between the refractory bricks and the metal component and between the refractory bricks are not constructed.)

[0018] Figure 2 It is the side sectional view of the tertiary air gate plate for a cement kiln with ventilation and cooling functions.

[0019] Figure 3 It is the schematic front sectional view of the plate-shaped heat-resistant metal component inside the tertiary air gate plate.

[0020] Figure 4 It is the schematic structural diagram of the refractory brick for the tertiary air gate plate.

[0021] In the figure: 1 - hollow plate-shaped metal component, 2 - refractory brick, 3 - heat-resistant metal bolt, 4 - heat-resistant metal nut, 5 - amorphous refractory material, 6 - high-abrasion-resistant amorphous refractory material, 7 - high-abrasion-resistant refractory material, 8 - gate plate lifting hook, 101 - heat-resistant metal partition in the hollow cavity, 102 - air inlet, 103 - air outlet, 201 - through hole with a step on the refractory brick. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Example 1:

[0023] Select a plate-shaped metal member 1 made of 310 material, a heat-resistant stainless steel plate with a thickness of 12 mm, to make the damper of the tertiary air duct. The length of the metal member is 3 m, the width is 2 m, and the total thickness is 80 mm (the width of the hollow cavity is 56 mm). The hollow cavity is vertically divided into three compartments by 310 steel plates 101. The three divided compartments are connected at the bottom. Normal temperature air for cooling is introduced into the left and right compartments. After the air is heated, it converges into the middle compartment from the bottom, and the hot air is led out from the upper air outlet. Use metal Si powder, industrial SiC particles (0.1 - 2.5 mm) and fine powder (0 - 0.065 mm), through mixing, vibration pressing, drying, and nitriding firing, to make Si3N4 bonded SiC hanging bricks 2. The size of the hanging bricks 2 is 328×328×45 mm. There are 2 through holes 201 on each hanging brick 2. The distance between the through holes 201 is 110 mm. The diameter of the large mouth above the through hole 201 is 25 mm, and the diameter of the small mouth below is 13 mm. The physical and chemical indexes of the hanging bricks 2 are: 75.2% SiC, 20.3% Si3N4, 0.25% Fe2O3, bulk density 2.70 g•cm -3 , apparent porosity 13.5%, cold crushing strength 220 MPa, flexural strength at 1350 °C 52 MPa; use 310S to make bolts 3 with a diameter of 12 mm and a length of 40 mm, and use 310S to make nuts 4 with a thickness of 8 mm, an outer diameter of 20 mm, and an inner diameter of M12; select silica with a particle size of 0.1 - 0.5 mm, 325-mesh clay, aluminate cement, carboxymethyl cellulose and water to prepare low-form refractory material 5. The chemical composition of the refractory material is Al2O3 18%, SiO2 78%, bulk density 1.7 g•cm-3, thermal conductivity (500 °C) is 1.2 W•m -1 •K -1 . Use industrial SiC particles (0.1 - 1.5 mm), SiC fine powder (0 - 0.045 mm), corundum particles (0.1 - 1.2 mm), corundum fine powder (0 - 0.045 mm), and SiO2 fine powder as raw materials. After proportioning these raw materials, mix them evenly, and then add aluminum dihydrogen phosphate solution to prepare SiC - Al2O3 quality wear-resistant ramming material as high wear-resistant refractory material 6. The chemical composition of the high wear-resistant refractory material 6 is SiC 50%, Al2O3 45.1%, bulk density 2.80 g•cm -3Using industrial SiC particles (0.1 - 1.5 mm), SiC fine powder (0 - 0.045 mm), corundum particles (0.1 - 1.2 mm), and corundum fine powder (0 - 0.045 mm) as raw materials, after proportioning these raw materials and mixing them evenly, silica sol is added to prepare the SiC - Al₂O₃ based wear - resistant plastic mass as the high - wear - resistant refractory material 7. The chemical composition of the plastic mass is SiC 75%, Al₂O₃ 20%, and the bulk density is 2.55 g•cm -3 .

[0024] The bolt 3 is welded on the metal component 1 by a welding machine. The vertical spacing of the bolts 3 used for each hanging brick 2 is about 110 ± 1 mm, and the horizontal spacing is 333 ± 1 mm. After the bolts 3 are welded, the unshaped refractory material 5 is applied on the outer surface of the metal component 1 with a thickness of 6 - 8 mm. The through - hole of the hanging brick 2 is aligned with the bolt 3 and hung on. The hanging plate 2 is tightened, so that a small amount of the applied slurry overflows from around the hanging brick 2, and then the nut 4 is tightened to keep the gap between the hanging plate 2 and the metal component 1 at 5 - 5.5 mm. After all the hanging bricks 2 are installed, the 5 - 6 mm brick joints between the hanging bricks 2 are filled tightly with the high - wear - resistant unshaped refractory material 6. Then, the space above the bolt 3 and the nut 4 in the through - hole 201 of the hanging brick is filled with the wear - resistant plastic mass 7 until it is flush with the surface of the hanging brick 2. Finally, the installed throttle plate is baked at a baking temperature of 380 °C for 8 hours of heat preservation. After cooling, the tertiary air throttle plate is obtained.

[0025] This throttle plate is installed at the position of the tertiary air duct valve. Under the condition of ventilation and cooling, the outlet temperature is controlled at 300 °C, and the service life of the throttle plate exceeds 2 years. If it is difficult to install ventilation facilities on - site, under the condition of non - ventilation and cooling, the throttle plate can still be used for 10 months. Example 2:

[0026] Select a plate-shaped metal component 1 of the tertiary air duct damper made of Q235b steel quality and 15 mm thick heat-resistant steel plate. The length of the metal component is 2.5 m, the width is 1.6 m, and the total thickness is 90 mm (the width of the hollow cavity is 60 mm). The hollow cavity is vertically divided into three compartments by 304 stainless steel plates 101. The three divided compartments are connected at the bottom. Normal temperature air for cooling is introduced into the left and right compartments. After the air is heated, it converges into the middle compartment from the bottom, and the hot air is led out from the upper air outlet. Use electrofused Al2O3 particles (0.1~3 mm), Al2O3 fine powder (average particle size 0.002 mm), industrial SiC particles (0.5~1.0 mm) and fine powder (<0.045 mm), SiO2 fine powder (average particle size 0.0015 mm), through mixing, machine pressing, drying, and firing at 1500 °C, prepare a SiC-Al2O3-SiO2 composite refractory hanging plate 2 with mullite as the bonding phase. The size of the hanging plate 2 is 308×300×50 mm. There are 2 through holes 201 on each hanging brick 2. The distance between the through holes 201 is 120 mm. The upper large mouth diameter of the through hole 201 is 30 mm, and the lower small mouth diameter is 15 mm. The physical and chemical indexes of the hanging brick 2 are: Al2O3 45.5%, SiC 49.5%, SiO2 4.5%, Fe2O3 0.2%, bulk density 2.76 g•cm -3 , apparent porosity 12%, normal temperature compressive strength 135 MPa, flexural strength at 1200 °C 30 MPa. Use 310S to make bolts 3 with a diameter of 14 mm and a length of 48 mm, and use 310S to make nuts 4 with a thickness of 10 mm, an outer diameter of 28 mm, and an inner diameter of M14. Select 0.1~1 mm high alumina bauxite particles, pyrophyllite particles (0.1-0.5 mm), silica particles (0.1~0.5 mm), 325 mesh clay, high alumina cement, carboxymethyl cellulose and water to prepare unshaped refractory 5. The chemical composition of the unshaped refractory is Al2O3 50.5%, SiO2 48%, bulk density 2.3 g•cm -3 , thermal conductivity (500 °C) is 1.8 W•m -1 •K -1 ; Use industrial SiC particles (0.1~1.5 mm), SiC fine powder (0~0.045 mm), electrofused brown corundum particles (0.1~1.5 mm), white corundum fine powder (0~0.045 mm), SiO2 fine powder, and aluminate cement as raw materials. After weighing these raw materials according to the formula and mixing them evenly, add an appropriate amount of water to prepare a SiC-Al2O3-SiO2 quality wear-resistant ramming material as the high wear-resistant unshaped refractory 6. The chemical composition of the ramming material is SiC 35%, Al2O3 60%, bulk density 2.93 g•cm -3; Using industrial SiC particles (0.1 - 1.5 mm), SiC fine powder (0 - 0.045 mm), corundum particles (0.1 - 1.2 mm), corundum fine powder (0 - 0.045 mm), and clay fine powder as raw materials. After proportioning these raw materials and mixing them evenly, phosphoric acid solution is added to prepare the SiC - Al2O3 - SiO2 - based plastic refractory as the highly wear - resistant refractory material 7. The chemical composition of the plastic refractory is SiC 40.5%, Al2O3 50.6%, and the bulk density is 2.60 g•cm -3 .

[0027] Process M14 screw holes with a depth of 12 mm on the metal component 1. The vertical spacing of the screw holes corresponding to each hanging brick is 120 ± 1 mm, and the horizontal spacing is 305 ± 1 mm. Screw the bolt 3 tightly into the screw holes, and then apply the unshaped refractory material 5 on the outer surface of the metal component 1 with a thickness of 8 - 9 mm. Align the through - holes of the hanging bricks 2 with the bolts 3 and hang them up. Press the hanging plates 2 tightly. After a small amount of the smeared slurry overflows from around the hanging bricks 2, tighten the nuts 4 to keep the gap between the hanging plates 2 and the metal component 1 about 6 mm. After all the hanging bricks 2 are installed, fill the 6 - 7 mm brick joints between the hanging bricks 2 with the highly wear - resistant unshaped refractory material 6. Then fill the voids above the bolts 3 and nuts 4 in the through - holes 201 of the hanging bricks with the highly wear - resistant refractory material 7 until the surface of the highly wear - resistant refractory material 7 is flush with the surface of the hanging bricks 2. Finally, bake the installed damper plate at a baking temperature of 350 °C for a heat - preservation time of 10 hours. After cooling, the tertiary air damper plate is obtained.

[0028] This damper plate is installed at the position of the tertiary air duct valve. Under the condition of ventilation and cooling, control the outlet air temperature at 250 °C, and the service life of the damper plate exceeds 2 years; if it is difficult to install ventilation facilities on - site, under the condition of non - ventilation and cooling, the damper plate can still be used for more than 6 months.

Claims

1. A tertiary air damper for a cement kiln with ventilation and cooling functions, characterized in that: The tertiary air damper has a plate-shaped heat-resistant metal member as a framework; the plate-shaped heat-resistant metal member is of a hollow structure; a refractory brick wall is installed on the outer wall surface of the plate-shaped heat-resistant metal member; an amorphous refractory material with a low thermal conductivity is filled between the refractory brick wall and the outer wall surface of the plate-shaped heat-resistant metal member; the refractory brick wall is composed of multiple refractory hanging bricks suspended on the outer wall surface of the plate-shaped heat-resistant metal member; a highly wear-resistant amorphous refractory material is filled between every two adjacent refractory hanging bricks.

2. The triple air damper for a cement kiln with a ventilation and cooling function according to claim 1, wherein: The hollow cavity of the plate-shaped heat-resistant metal member is divided into multiple vertical channels, and the multiple vertical channels communicate with each other; a lifting hook is installed on the upper part of the plate-shaped heat-resistant metal member, and an air inlet and an air outlet are provided.

3. The triple air damper for a cement kiln with a ventilation and cooling function according to claim 1, wherein: The refractory hanging bricks are fixed on the outer surface of the plate-shaped heat-resistant metal member through metal bolts and nuts.

4. The triple air damper for a cement kiln with a ventilation and cooling function according to claim 3, characterized in that: The metal bolts are vertically fixed on the outer surface of the plate-shaped heat-resistant metal member by welding or threading, and the diameter of the metal bolts is ≤ 25 mm.

5. The triple air damper for a cement kiln with a ventilation and cooling function according to claim 1, characterized in that: Each refractory hanging brick contains 1 to 3 stepped straight through holes, and the length, width and thickness of the hanging brick are ≤ 400 mm and ≤ 80 mm respectively.

6. The triple air damper for a cement kiln with a ventilation and cooling function according to claim 1, characterized in that: The hot air temperature at the air outlet of the plate-shaped heat-resistant metal member is controlled to be ≤ 400 °C.

7. The triple air damper for a cement kiln with a ventilation and cooling function according to claim 1, characterized in that: The hot air temperature at the air outlet of the plate-shaped heat-resistant metal member is 150 - 300 °C.

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