A furnace lining structure and repair process for lime shaft kiln gunning repair

Abstract

A furnace lining structure and repair process for lime shaft kiln gunning repair relates to the technical field of furnace lining repair. It comprises a first anchor, a second anchor, an expansion bolt, a first anchor net, a second anchor net, a plurality of expansion bolts are fixed on the refractory brick layer, the first anchor and the second anchor are fixed on the expansion bolt, the first anchor net is close to the refractory brick layer, the second anchor net is arranged on the inner side of the first anchor net, the first anchor net and the second anchor net are poured with a spraying layer, the double-layer staggered anchor net is arranged on the working layer in the kiln, the anchor is arranged in the staggered position, the stretching limit in the horizontal direction and the vertical direction is carried out, and the wet gunning process can effectively improve the tightness, strength and wear resistance of the lining material, so that the rapid repair of the lining of the lime shaft kiln is realized, and the working life of the lining is prolonged.

Description

Technical Field

[0001] The invention relates to a furnace lining structure and a repair process for a lime shaft kiln gunning repair, and relates to the technical field of furnace lining repair. Background Art

[0002] During the production process of a vertical lime kiln, after long-term use, the kiln lining bricks will be severely worn and eroded, and the refractory materials in the combustion zone and the preheating zone working layer will be burned and fall off. In addition, a large area of ​​bricks will fall off above the flue bottom plate, that is, in the straight section of the kiln mouth, causing the upper kiln ring to tilt and the material distribution in the kiln to be uneven. It is necessary to adjust the coal-stone ratio to improve product quality, resulting in increased energy consumption, which is not conducive to energy-saving production and also poses a safety hazard.

[0003] In order to repair the lime shaft kiln that has been put into production, the existing technology usually adopts a semi-dry spraying method, in which dry powder spray material is transported to the spray gun nozzle through a pipeline using high-pressure gas, water is added at the spray gun nozzle for premixing, and then the paint is sprayed on the lining to repair the lime kiln lining. However, the amount of water added in this method is difficult to meet the precise requirements. In addition, the dry powder spray material material and water are premixed for a short and uneven time before being sprayed onto the wall, resulting in a large amount of dust and a high rebound rate of aggregates, resulting in poor density, strength and wear resistance of the sprayed surface, which affects the service life of the furnace lining. Therefore, a lining structure and repair process for lime shaft kiln gunning repair are proposed to solve the problems existing in the existing technology. Summary of the Invention

[0004] The purpose of the present invention is to address the defects or shortcomings in the existing technology and provide a lining structure for lime shaft kiln gunning repair. By adopting a double-layer staggered anchoring mesh set on the working surface of the kiln and arranging anchor pieces at the staggered positions, transverse and longitudinal stretching limiting is performed. In combination with the wet spraying process, the tightness, strength and wear resistance of the lining material can be effectively improved, thereby achieving rapid repair of the lime shaft kiln lining and extending the working life of the lining.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: it includes a first anchor 1, a second anchor 2, an expansion bolt 8, a first anchoring net, and a second anchoring net. Several expansion bolts 8 are fixed on the refractory brick layer 9, the first anchor 1 and the second anchor 2 are both fixed on the expansion bolt 8, the first anchoring net is close to the refractory brick layer 9, the second anchoring net is arranged on the inner side of the first anchoring net, and a spray coating 10 is cast between the first anchoring net and the second anchoring net.

[0006] Furthermore, the first anchoring mesh includes first longitudinal steel bars 3 and first transverse steel bars 5, and a plurality of first longitudinal steel bars 3 and first transverse steel bars 5 are cross-welded to form the first anchoring mesh.

[0007] Furthermore, the second anchoring mesh includes second longitudinal steel bars 4 and second transverse steel bars 6. Several second longitudinal steel bars 4 and second transverse steel bars 6 are cross-welded to form the second anchoring mesh, and the cross-welding points between the second anchoring mesh and the first anchoring mesh are staggered.

[0008] Furthermore, the first anchor 1 and the second anchor 2 have the same structure.

[0009] Furthermore, the first anchor 1 includes an anchor body 11, a front limit plate 12, a rear limit plate 13, and a fixing plate 14. The front limit plate 12 and the rear limit plate 13 are obliquely arranged at the top of the anchor body 11, and the fixing plate 14 is arranged at the bottom of the anchor body 11.

[0010] Furthermore, the fixing plate 14 is provided with a fixing hole 15 .

[0011] Furthermore, the angle between the front limiting plate 12 and the rear limiting plate 13 is 60 degrees.

[0012] Furthermore, the first anchor 1 is arranged with a first longitudinal steel bar 3 at a transverse interval, the first anchor 1 is arranged with a first transverse steel bar 5 at a longitudinal interval, and the second anchor 2 is arranged in the same manner as the first anchor 1, but the second anchor 2 is arranged starting from the interval of the first anchor 1, thereby forming a staggered grid structure.

[0013] Furthermore, the anchor body 11 of the first anchor 1 is arranged below the first transverse reinforcement 5 and the second transverse reinforcement 6, and the end of the anchor body 11 of the second anchor 2 is located above the first transverse reinforcement 5, and the front end passes through from below the second transverse reinforcement 6.

[0014] Furthermore, the anchor body 11 , the front limiting plate 12 , and the rear limiting plate 13 are coated with an asphalt coating.

[0015] After adopting the above technical solution, the beneficial effects of the present invention are as follows: by adopting a double-layer staggered anchoring mesh to be set on the working surface of the kiln, and arranging anchors at the staggered positions, horizontal and vertical stretching limiting is performed, and combined with the wet spraying process, the tightness, strength and wear resistance of the lining material can be effectively improved, thereby achieving rapid repair of the lining of the lime shaft kiln and extending the working life of the lining. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 yes Figure 1 A top view of

[0019] Figure 3 yes Figure 2 Middle AA section view;

[0020] Figure 4 yes Figure 3 The enlarged structural diagram at B in the middle;

[0021] Figure 5 yes Figure 3 The enlarged structural diagram at C in the middle;

[0022] Figure 6 It is a structural schematic diagram of the first anchor 1 in the present invention;

[0023] Figure 7 yes Figure 6 A second angle view of

[0024] Figure 8 yes Figure 6 A third angle view of

[0025] Figure 9 It is a schematic diagram of the construction effect of the present invention in a lime shaft kiln.

[0026] Explanation of the accompanying drawings: first anchor 1, second anchor 2, first longitudinal reinforcement 3, second longitudinal reinforcement 4, first transverse reinforcement 5, second transverse reinforcement 6, bolt 7, expansion bolt 8, refractory brick layer 9, spray coating 10, fixture body 11, front limit plate 12, rear limit plate 13, fixing plate 14, fixing hole 15. DETAILED DESCRIPTION

[0027] See Figures 1-9 As shown, the technical solution adopted in this specific embodiment is: a lining structure for lime shaft kiln gunning repair, which includes a first anchor 1, a second anchor 2, an expansion bolt 8, a first anchoring net, and a second anchoring net. Several expansion bolts 8 are fixed on the refractory brick layer 9, the first anchor 1 and the second anchor 2 are fixed on the expansion bolt 8, the first anchoring net is close to the refractory brick layer 9, the second anchoring net is arranged on the inner side of the first anchoring net, and a spraying layer 10 is poured between the first anchoring net and the second anchoring net. The lining of the traditional lime shaft kiln will fall off after a long period of operation, which not only affects the product quality and increases energy consumption, but also poses a safety hazard. Therefore, in this embodiment, anchors and anchoring nets are used as the main frame of the lining, with a length of 200m 3Taking the energy-saving lime shaft kiln as an example, the specific operation is to drive the expansion bolts into the refractory brick layer. The expansion bolts are arranged in a grid form. The size of the expansion bolts is: ￠10*120, with a spacing of 250mm*250mm. The anchors are then fixed to the expansion bolts with bolts. At the same time, steel bars are used for welding, and full welding must be ensured. After the anchor welding is completed, the anchor net is installed. The first anchor net is welded to the anchor close to the refractory brick layer. The second anchor net is welded to the front end of the anchor at intervals from the first anchor net. The two layers of anchor nets cooperate with the anchors to form a three-dimensional protective structure, which can better form the inner lining layer.

[0028] To be more specific, the first anchoring mesh includes a first longitudinal steel bar 3 and a first transverse steel bar 5, and several first longitudinal steel bars 3 and first transverse steel bars 5 are cross-welded to form a first anchoring mesh; the second anchoring mesh includes a second longitudinal steel bar 4 and a second transverse steel bar 6, and several second longitudinal steel bars 4 and second transverse steel bars 6 are cross-welded to form a second anchoring mesh, and the cross-welding points of the second anchoring mesh and the first anchoring mesh are staggered. In this embodiment, the two anchoring meshes are staggered to obtain better tensile resistance, and the overall firmness and tightness are better after the inner lining layer is formed by spray casting.

[0029] To be more specific, the first anchor 1 and the second anchor 2 have the same structure. The first anchor 1 includes an anchor body 11, a front limiting plate 12, a rear limiting plate 13, and a fixed plate 14. The front limiting plate 12 and the rear limiting plate 13 are obliquely arranged at the top of the anchor body 11, and the fixed plate 14 is arranged at the bottom of the anchor body 11. The angle between the front limiting plate 12 and the rear limiting plate 13 is 60 degrees. In this embodiment, inclined front and rear limiting plates are arranged on the top of the anchor, which can form a limiting structure after being welded with the anchor mesh. After the spray coating is cast, it will form a limiting effect on the spray coating, which can more effectively prevent the occurrence of collapse.

[0030] More specifically, the fixing plate 14 is provided with fixing holes 15 for installing bolts, and the fixing plate is compressed by nuts to be more secure when welding with steel bars.

[0031] To be more specific, the first anchor 1 is arranged with a first longitudinal steel bar 3 at a transverse interval, the first anchor 1 is arranged with a first transverse steel bar 5 at a longitudinal interval, the second anchor 2 is arranged in the same manner as the first anchor 1, but the second anchor 2 is arranged starting from the interval of the first anchor 1, thereby forming a staggered grid structure, the anchor body 11 of the first anchor 1 is arranged below the first transverse steel bar 5 and the second transverse steel bar 6, the end of the anchor body 11 of the second anchor 2 is located above the first transverse steel bar 5, and the front end passes through from below the second transverse steel bar 6. In this embodiment, the first and second anchors are staggered, and the second anchor also passes between the two transverse steel bars, which can support the transverse steel bars of this row from two directions, and can provide better supporting effect after welding, and the overall structure is more solid.

[0032] To be more specific, the anchor body 11, the front limit plate 12, and the rear limit plate 13 are coated with an asphalt coating. The anchor is a very important metal component connecting the spray coating and the furnace body itself in spray construction. In order to effectively control the expansion coefficient between the spray coating and the metal, and avoid cracks in the spray coating and material falling off the spray surface, a layer of asphalt is applied to the end of the anchor after construction, thereby effectively protecting the anchor and the spray coating, thereby effectively protecting the overall working life.

[0033] This embodiment also provides a lining repair process for lime shaft kiln gunning repair, which adopts a wet spraying process and includes the following process steps:

[0034] Step 1, material selection; HL-65G wear-resistant spray coating is selected and mixed with water in a mixer. Since the surface of the spray coating in the furnace lining is not only impacted and rubbed by limestone, but also blasted by the kiln bottom, eroded by hot flue gas and contacted by open flames, the spray coating is required to have a high temperature resistance of more than 1200°C and a material with high compressive strength, high flexural strength, thermal conductivity and small linear variation rate. Therefore, HL-65G wear-resistant spray coating is selected in this embodiment, which can form an effective wear-resistant lining layer after pouring;

[0035] Step 2, steel selection; Due to the different temperatures in the furnace lining, the thermal expansion coefficients of different parts are inconsistent, and when large thermal stress is generated, it is easy to cause the welds to crack, causing the anchors and the gunning material to fall off together. In this embodiment, 0Cr25Ni20 heat-resistant stainless steel bars are selected as the anchor material. It has a high percentage of chromium and nickel, which makes it have high creep strength and can continue to operate at high temperatures. It not only has oxidation resistance and corrosion resistance, but also has good high temperature resistance and carburization resistance.

[0036] Step 3, cleaning the kiln; clean the eroded parts of the inner wall of the lime kiln, and remove the nodules, slag, attachments, etc. in the entire furnace lining, and remove the loose refractory bricks. If there are many nodules in the kiln, use high-pressure water mist to spray the nodules at the kiln wall at about 300°C. Spray continuously for 5 minutes at each location, and then let it pulverize naturally. If the pulverization is not completely removed, repeatedly spray with high-pressure water mist until the pulverization is clean. After the water-spraying and nodule removal operation, all the nodules on the kiln wall have fallen off. This not only has no effect on the life of the kiln wall, but also reduces the workload of subsequent manual nodule removal and speeds up the project progress. This is an important process. Whether the kiln wall is clean before spraying is directly related to the service life of the spray material.

[0037] Step 4, anchors and anchor nets are arranged; expansion bolts are driven into the surface of the working layer (refractory brick layer) in the kiln, and anchors are installed. The expansion bolt size is: ￠10*120, with a spacing of 250mm*250mm. After the expansion bolts are planted, the anchors are locked on the nuts and then fully welded with stainless steel welding rods. The installation of anchors needs to be determined according to the erosion situation. If the kiln lining peels off to the kiln shell, the anchor nails are directly welded to the kiln shell. If the erosion is not serious, they are normally installed on the refractory brick layer. After the anchors are arranged, the anchor net is welded. The first layer of anchor net is welded to the refractory brick layer and the anchor, and the second layer of anchor net is welded to the end of the anchor. The double-layer anchor net not only protects the installation surface, but also better forms a three-dimensional framework for easy subsequent operations.

[0038] Step 5: Anchor coating: Anchors are very important components in spray coating construction, connecting the spray coating and the furnace body itself. In order to effectively control the expansion coefficient between the spray coating and the metal and avoid cracks in the spray coating and material shedding on the spray surface, a layer of asphalt is applied to the end of the anchor after construction to form an asphalt layer to protect the anchor.

[0039] Step 6, kiln cleaning: After the mesh is hung, the kiln is cleaned by blowing high-pressure gas to clean the kiln wall to ensure that there are no impurities on the kiln wall;

[0040] Step 7: Hang the center line. To ensure that the entire kiln body meets the design requirements of the original drawing after spraying, find the center point from the kiln surface to the kiln bottom, hang the vertical center line, and install multiple probes according to the radius of each zone in the kiln according to the drawing to determine whether the spraying thickness meets the kiln radius requirements.

[0041] Step 8, test spraying; In order to achieve the ideal spraying effect, a test spraying is required before the formal spraying operation to determine the optimal water addition amount, spraying pressure and jet speed. Since wet spraying is used, the rebound amount is required to be controlled within 8%. After the test spraying is completed, natural drying is mainly used, and the sound of the sprayed surface being hit with a hammer is used to judge the strength;

[0042] Step 9: Anchor inspection: Check whether the anchors and anchor mesh at each part are fully welded and whether the welding is reliable; whether the spacing and row spacing of the anchors are controlled at about 250mm to prevent the anchors from falling off and causing cracking or falling off of the sprayed surface;

[0043] Step 10, spraying; the spray material after stirring evenly is transported to the nozzle through the hose by the pressure pump equipped with the sprayer. The nozzle is equipped with a water pipe, which can pass through the liquid coagulant. The wet-mixed spray material and the coagulant are mixed in the nozzle and then sprayed out from the nozzle to enter the formal spraying stage. When the spraying construction begins, the material is continuously pumped and the construction is uninterrupted to avoid flashing and flowing of the material on the spraying surface. The spray gun should be tilted vertically downward to the sprayed surface and keep a reasonable distance from the sprayed surface. First, start with the deepest concave part of the furnace lining erosion, and then carry out the overall spiral spraying from top to bottom. Lining construction, material construction speed is controlled at 13-15t / h. When spraying, an adjustable screw should be used to check whether the kiln radius and spray thickness meet the design requirements. If not, spray from bottom to top to meet the design thickness requirements at one time to ensure that there is no interlayer in the sprayed part. The spray material is poured on the anchoring net and anchoring pieces by spraying to form a spray layer. Due to the high pressure of the wet spraying equipment, the spray surface attached to the furnace lining after spraying is more dense. Therefore, the wet spraying process is combined with pouring and spraying to effectively improve the tightness, strength and wear resistance of the lining material.

[0044] Step 11, ignite the kiln; gradually remove the moisture from the spray paint inside the kiln lining by slowly heating, so as to avoid damage such as cracks and falling off of the refractory materials in the kiln due to the rapid increase in temperature and the rapid discharge of moisture during the kiln opening process. For specific kiln temperature control, please refer to the kiln temperature control table. By segmented heating, the final repair of the lining can be effectively completed.

[0045] Kiln temperature control table

[0046]

[0047] The traditional masonry repair process combined with dry spraying is not only time-consuming, usually more than 15 days, but also involves material waste, resulting in high material consumption and poor results. In this embodiment, the main frame of the lining layer is built by anchors and anchor nets, and then a wet spray repair process is used. This can effectively shorten the maintenance time of the kiln shutdown and reduce the losses caused by the shutdown. At the same time, it improves the kiln wall effect, truly embodying the four major advantages of saving time, labor, materials, and safety.

[0048] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A lining structure for lime shaft kiln gunning repair, characterized by: The invention comprises a first anchor (1), a second anchor (2), an expansion bolt (8), a first anchoring net, and a second anchoring net. A plurality of expansion bolts (8) are fixed on a refractory brick layer (9). The first anchor (1) and the second anchor (2) are both fixed on the expansion bolts (8). The first anchoring net is in close contact with the refractory brick layer (9). The second anchoring net is arranged on the side of the first anchoring net away from the refractory brick. A spray coating (10) is poured between the first anchoring net and the second anchoring net. The first anchor (1) is arranged with a first longitudinal steel bar (3) at intervals in the transverse direction. The first anchor (1) is arranged with a first transverse steel bar (5) at intervals in the longitudinal direction. The second anchor (2) is arranged in the same manner as the first anchor (1), but the second anchor (2) is arranged starting from the interval between the first anchor (1), thereby forming a dislocated grid structure.

2. The lining structure for lime shaft kiln gunning repair according to claim 1, characterized in that: The first anchoring net comprises a first longitudinal steel bar (3) and a first transverse steel bar (5), wherein a plurality of the first longitudinal steel bars (3) and the first transverse steel bars (5) are cross-welded to form the first anchoring net; the second anchoring net comprises a second longitudinal steel bar (4) and a second transverse steel bar (6), wherein a plurality of the second longitudinal steel bars (4) and the second transverse steel bars (6) are cross-welded to form the second anchoring net, and cross-welding points of the second anchoring net and the first anchoring net are staggered.

3. The lining structure for lime shaft kiln gunning repair according to claim 1, characterized in that: The first anchor (1) comprises an anchor body (11), a front limiting plate (12), a rear limiting plate (13), and a fixing plate (14); the front limiting plate (12) and the rear limiting plate (13) are arranged obliquely on the top of the anchor body (11); and the fixing plate (14) is arranged on the bottom of the anchor body (11).

4. The lining structure for lime shaft kiln gunning repair according to claim 3, characterized in that: The fixing plate (14) is provided with a fixing hole (15).

5. The lining structure for lime shaft kiln gunning repair according to claim 3, characterized in that: The angle between the front limiting plate (12) and the rear limiting plate (13) is 60 degrees.

6. A lining structure for lime shaft kiln gunning repair according to any one of claims 3 to 5, characterized in that: The first anchoring piece (1) and the second anchoring piece (2) have the same structure.

7. The lining structure for lime shaft kiln gunning repair according to claim 3, characterized in that: The anchor body (11), the front limiting plate (12) and the rear limiting plate (13) are coated with an asphalt coating.

8. A lining repair process for lime shaft kiln gunning repair, characterized by: The wet spraying process includes the following steps: Step 1, material selection: select HL-65G wear-resistant spray paint and mix it with water in a blender; Step 2, steel selection: 0Cr25Ni20 heat-resistant stainless steel bars are selected as anchor material; Step 3: Clean the kiln: clean the eroded parts of the inner wall of the lime kiln, remove the tumors, slag, and attachments in the entire furnace lining, and remove the loose refractory bricks; Step 4: Arrange anchors and anchoring nets. Drive expansion bolts into the refractory brick layer and install anchors. The expansion bolt size is ¢10*120, with a spacing of 250mm*250mm. After the expansion bolts are planted, lock the anchors onto the nuts and then weld them fully with stainless steel welding rods. The installation of anchors needs to be determined according to the corrosion situation. Step 5, anchor coating; After construction, apply a layer of asphalt to the end of the anchor to form an asphalt layer to protect the anchor; Step 6, kiln cleaning: After the mesh is hung, the kiln is cleaned by blowing high-pressure gas to clean the kiln wall to ensure that there are no impurities on the kiln wall; Step 7: Hang the center line. To ensure that the entire kiln body meets the design requirements of the original drawing after spraying, find the center point from the kiln surface to the kiln bottom, hang the vertical center line, and install multiple probes according to the radius of each zone in the kiln according to the drawing to determine whether the spraying thickness meets the kiln radius requirements. Step 8, test spraying; in order to achieve the ideal spraying effect, a test spraying is required before the formal spraying operation to determine the optimal amount of water, spraying pressure and jet speed, and the rebound amount is controlled within 8%. After the test spraying is completed, it is mainly dried naturally, and the strength is judged by the sound of the sprayed surface being hit with a hammer; Step 9: Anchor inspection: Check whether the anchors and anchor mesh at each location are fully welded and whether the welding is reliable; whether the spacing and row spacing of the anchors are controlled within 250mm; Step 10, spraying; the spray material after stirring evenly is transported to the nozzle through a hose by a pressure pump equipped with a sprayer. The nozzle is equipped with a water pipe. Through the liquid coagulant, the wet-mixed spray material and the coagulant are mixed in the nozzle, and then sprayed from the nozzle to enter the formal spraying stage. When the spraying construction begins, the material is continuously pumped and the construction is uninterrupted to avoid flashing and flowing of the material on the spraying surface. The spray gun should be tilted vertically downward to the sprayed surface and maintain a reasonable distance from the sprayed surface. First, start with the concave part where the furnace lining is most eroded, and then carry out the mobile spraying and lining construction from top to bottom in a spiral manner. The material construction speed is controlled at 13-15 t / h. When spraying, an adjustable screw should be used to check whether the radius of the kiln and the spraying thickness meet the design requirements. If they do not meet the requirements, spray from bottom to top to meet the design thickness requirements at one time to ensure that there is no interlayer in the sprayed part. The spray material is poured on the anchor net and anchor to form a spray layer. Step 11, ignite the furnace; gradually remove the moisture of the spray paint inside the kiln lining by slowly heating.

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