CN111271977A

CN111271977A - Repair method for prefabricated module at bottom of suspension cylinder of Maerz lime kiln

Info

Publication number: CN111271977A
Application number: CN202010087271.0A
Authority: CN
Inventors: 张楼清; 赵鸣; 王俊刚; 李强; 宋界勇; 孙婷婷
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd
Priority date: 2020-02-11
Filing date: 2020-02-11
Publication date: 2020-06-12
Anticipated expiration: 2040-02-11
Also published as: CN111271977B

Abstract

The invention discloses a repairing method of a prefabricated module at the bottom of a suspension cylinder of a Maerz lime kiln, and belongs to the field of furnace kiln refractory repairing. The provided repairing method converts all materials into domestic materials, the materials are convenient to purchase and cheap, and the manufacturing cost is reduced; the 52 prefabricated modules in each chamber are changed into 13 prefabricated modules, so that the gaps among the prefabricated modules are reduced, and meanwhile, the problem that the construction period is prolonged due to the long loading period of foreign purchases is solved by adopting a cast-in-place mode; the design structure is more reasonable, and the service cycle of the prefabricated module is prolonged; the damaged prefabricated modules can be locally poured again, and the installation and disassembly cost is saved.

Description

Repair method for prefabricated module at bottom of suspension cylinder of Maerz lime kiln

Technical Field

The invention belongs to the field of repair of refractory materials of kilns, and particularly relates to a repair method of a prefabricated module at the bottom of a suspension cylinder of a Maerz lime kiln.

Background

At present, the steel-clad wheat kiln with a 600-ton daily-output suspension cylinder structure is manufactured by three steel-clad wheat kilns, the bottom of a suspension cylinder is of an inlet prefabricated module structure, but the actual use effect is not ideal, the prefabricated module falls off after being used for one year, and the refractory on the outer wall of the suspension cylinder has to be stopped for repair due to the falling of the refractory. The suspension cylinder prefabricated module does not have a production unit at present at home, and if the prefabricated module is replaced, the suspended cylinder prefabricated module can only be imported from foreign countries; the method has the advantages of long feeding period, high price and poor use effect.

Disclosure of Invention

Aiming at one or more problems in the prior art, the invention provides a repairing method of a prefabricated module at the bottom of a suspension cylinder of a Maerz lime kiln, wherein the bottom of the suspension cylinder of the Maerz lime kiln comprises 52 prefabricated modules, 4 adjacent prefabricated modules are divided into one unit plate, the unit plate is divided into 13 unit plates in total, and the unit plates are sequentially named as unit plates 1-13; wherein the repair method comprises the following steps:

1) firstly, dismantling the prefabricated modules of the unit plate 2, the unit plate 4, the unit plate 6, the unit plate 8, the unit plate 10 and the unit plate 12 and all refractory materials on the prefabricated modules, reserving a prefabricated module bottom plate, and dismantling the damaged anchoring piece;

2) removing MSS ramming mass between the prefabricated module and a first ring high-alumina brick at the bottom of the suspension cylinder;

3) repairing or replacing the damaged original connecting plate, re-welding and installing the damaged original anchoring piece, and adding a V-shaped anchoring piece between the adjacent prefabricated module bottom plates in each unit plate, wherein the connecting plate is a connecting plate between the prefabricated module and the steel structure at the bottom of the suspension cylinder;

4) the method comprises the following steps of (1) coating asphalt paint on the head of an anchor part which is repaired, replaced and newly added, and pasting a refractory ceramic fiber pad on the lower surface of a bottom plate of a prefabricated module, the exposed part of a suspension cylinder, the lower surfaces of a first layer of bricks ZA-5686-N, DS 601-280 and DS 600-280, wherein the refractory ceramic fiber pad is subjected to waterproof treatment;

5) respectively erecting a formwork according to the size of the unit plate with the prefabricated module removed, and separating the unit plate with the prefabricated module removed from the unit plate without the prefabricated module removed by using a partition plate;

6) sequentially pouring the unit plates which are supported by the mold, wherein the pouring material flows into the mold from holes at two ends of the mold, and is fed while vibrating until the upper mold opening is leveled and the air is exhausted basically and completely;

7) after the castable in the unit plate 2, the unit plate 4, the unit plate 6, the unit plate 8, the unit plate 10 and the unit plate 12 is solidified, removing the prefabricated modules in the remaining unit plate 1, the remaining unit plate 3, the remaining unit plate 5, the remaining unit plate 7, the remaining unit plate 9, the remaining unit plate 11 and the remaining unit plate 13, and all the refractory materials on the prefabricated modules, retaining the prefabricated module bottom plates, and simultaneously removing the damaged anchoring members;

8) detaching the partition board in the step 5), and adhering a refractory ceramic fiber mat to the original partition board;

9) repeating the steps 2) to 6), and finishing the casting of all 13 unit plate blocks to obtain 13 cast bodies;

10) curing the solidified casting body, then removing the mold, and performing edge cutting treatment to ensure that the casting body is smooth and has no convex-concave defect, simultaneously checking the size of an expansion joint, controlling the size to be 5-6mm, and checking whether a suspension cylinder has missing casting and missing edges and corners;

11) and baking the casting body which meets the inspection qualification requirement.

And 4) adhering a refractory ceramic fiber mat with the thickness of 10mm to the lower surface of the prefabricated module bottom plate, adhering a refractory ceramic fiber mat with the thickness of 6mm to the exposed part of the suspension cylinder, and adhering a refractory ceramic fiber mat with the thickness of 10mm to the lower surfaces of the first layer of bricks ZA-5686-N, DS 601-280 and DS 600-280.

The castable in the step 6) is mullite steel fiber castable, wherein the addition amount of steel fibers is not less than 1% based on the total weight of the castable.

The baking in the step 11) is a two-stage baking, wherein the purpose of the first-stage baking is to remove free water in the internal structure part of the casting body, and the purpose of the second-stage baking is to remove bound water in the internal structure part of the casting body.

The first stage baking is carried out by drying and heating with an electric hot plate for 3 days, wherein the temperature of the first day is controlled within 120 ℃, the temperature of the second day is controlled within 200 ℃, and the temperature of the third day is controlled within 250 ℃.

The first-stage baking temperature rise control specifically comprises the following steps: the heating rate is 8 ℃/h-12 ℃/h within the range of less than or equal to 110 ℃, the constant temperature is set for a time at 110 ℃, the heating rate is 5 ℃/h within the range of 110 ℃ to 250 ℃, and the constant temperature is set for a time at 250 ℃; wherein the constant temperature setting time at 110 ℃ is 25h-30h, and the constant temperature setting time at 250 ℃ is 6h-10 h.

The second stage baking adopts a method of opening the kiln and igniting the kiln by a Mach-Zehnder kiln, the baking time is 5 days, wherein the temperature on the first day is controlled within 300 ℃, the temperature on the second day is controlled within 400 ℃, the temperature on the third day is controlled within 600 ℃, the temperature on the fourth day is controlled within 700 ℃, and the temperature on the fifth day is controlled within 900 ℃.

The temperature control of the second stage baking is specifically as follows: the temperature rise rate is 12.5 ℃/h within the range of less than or equal to 400 ℃, the constant temperature is set for 400 ℃, the temperature rise rate is 10 ℃/h within the range of 400 ℃ to 600 ℃, the constant temperature is set for 600 ℃, the temperature rise rate is 12.5 ℃/h within the range of 600 ℃ to 900 ℃, and the constant temperature is set for 900 ℃; the time set at the constant temperature of 400 ℃ is 20h, the time set at the constant temperature of 600 ℃ is 16h, and the time set at the constant temperature of 900 ℃ is 8 h.

The repair method for the prefabricated modules at the bottom of the suspension cylinder of the Maerz lime kiln, which is provided based on the technical scheme, can quickly repair the damaged prefabricated modules at the bottom of the suspension cylinder by utilizing on-site domestic construction conditions and materials so as to effectively replace imported prefabricated modules, and has the following beneficial effects compared with the prior art:

1) all materials are converted into domestic materials, the materials are convenient to purchase and cheap, and the manufacturing cost is reduced;

2) v-shaped anchoring parts are added between the prefabricated module bottom plates, so that the number of the anchoring parts on the outer side of the bottom of the suspension cylinder is increased, and the strength of the suspension cylinder is increased;

3) changing the original MSS ramming material into a casting material to integrate the MSS ramming material with a casting module; the low-cement pouring material which is the main material of the original imported prefabricated module is changed into the steel fiber pouring material, so that the thermal shock stability of the prefabricated module is improved, the generation of microcracks is reduced, and the service life is greatly prolonged;

4) the casting body is baked in two stages, firstly, free water in the internal structure of the casting body is removed, and then the casting body is further baked by adopting a method of igniting and baking a kiln by a wheat kiln, so that the damage to the casting body caused by igniting and baking the kiln by the wheat kiln is reduced; meanwhile, the scheme of igniting and drying the kiln is improved on the basis of the prior art, and the service life of the prefabricated module is greatly prolonged.

In conclusion, the repair method of the prefabricated module at the bottom of the suspension cylinder of the Mailz lime kiln, provided by the invention, not only has the service life far exceeding that of an imported prefabricated module, but also has the construction and material cost greatly lower than that of the imported module, the service life is prolonged to 60 months from 15 months, the capital can be saved by 647.04 ten thousand yuan only from the material cost and the construction cost, the kiln halt caused by two times of maintenance is reduced by 60 days, and the production halt loss is avoided by 297.68 ten thousand yuan. The method can be popularized and applied to three steel-clad suspension cylinder wheat kilns, can be popularized to all suspension cylinder wheat kilns with similar structures in China, can bring a new way for the localization of spare parts of production units in the same industry, and has great significance.

Drawings

Fig. 1 is a schematic structural view of 13 unit slabs divided by 52 prefabricated modules;

FIG. 2 is a schematic view of the addition of V-shaped anchors between the bottom plates of the precast modules;

FIG. 3 is a schematic structural view after casting a casting material in a part of the unit plate;

FIG. 4 is a schematic cross-sectional view taken along line A-A of FIG. 3;

FIG. 5 is a first stage baking temperature control curve;

FIG. 6 is an ignition kiln plan provided by McLetz;

FIG. 7 is a second stage baking temperature control curve.

Detailed Description

The present invention is explained in detail by the following detailed description and the accompanying drawings.

The embodiments are provided in order to provide detailed embodiments and specific procedures, which will help understanding of the present invention, but the scope of the present invention is not limited to the following embodiments.

Example 1:

the embodiment provides a repairing method for a prefabricated module at the bottom of a Maerz lime kiln suspension cylinder, wherein the prefabricated module at the bottom of the Maerz lime kiln suspension cylinder is a prefabricated module with an external inlet and 52 prefabricated modules in total, in the repairing method provided by the embodiment, firstly, 52 prefabricated modules are a unit plate according to 4 prefabricated modules and are divided into 13 unit plates, as shown in FIG. 1, and the 13 unit plates are respectively named as a unit plate 1, a unit plate 2, a unit plate 3, a unit plate 4, a unit plate 5, a unit plate 6, a unit plate 7, a unit plate 8, a unit plate 9, a unit plate 10, a unit plate 11, a unit plate 12 and a unit plate 13; the repair method provided by the embodiment specifically comprises the following steps:

1) and (3) removing the prefabricated modules imported from the outer sides of the damaged

unit plate blocks

2, 4, 6, 8, 10 and 12 at the bottom of the suspension cylinder and all refractory materials on the prefabricated modules and the prefabricated module bottom plates by using tools such as air picks, and removing the damaged anchoring parts. And (3) temporarily keeping the prefabricated modules of the

unit plates

1, 3, 5, 7, 9, 11 and 13 as upper masonry support protection, and after the

unit plates

2, 4, 6, 8, 10 and 12 are subjected to formwork support pouring, sequentially removing the prefabricated modules of the

unit plates

1, 3, 5, 7, 9, 11 and 13.

2) Demolish MSS ramming mass between prefabricated module and the first ring high-alumina brick of suspension cylinder bottom, care when demolishing, can not damage and hang cylinder and the first layer brick body in upper portion.

3) The damaged original connecting plate (the connecting plate between the prefabricated module and the steel structure at the bottom of the suspension cylinder) is repaired or replaced, the damaged original anchoring piece is welded and installed again, and a V-shaped anchoring piece 31 is additionally arranged between the original adjacent prefabricated module bottom plates respectively, as shown in figure 2, each chamber has 13 unit plates, 3V-shaped anchoring pieces 31 are additionally arranged in each unit plate, and therefore 39V-shaped anchoring pieces 31 are additionally arranged in each chamber. The V-shaped anchoring pieces 31 are added between the prefabricated module bottom plates, so that the number of anchoring pieces outside the bottom of the suspension cylinder is increased, and the strength of the suspension cylinder can be increased.

4) Coating asphalt paint on the head parts of the repaired, replaced and newly added anchoring parts, as shown in figures 3 and 4, and adhering refractory ceramic fiber mats on the lower surfaces of the bottom plates of the prefabricated modules, the exposed parts of the suspension cylinders, the lower surfaces of the first layers of bricks ZA-5686-N, DS 601-280 and DS 600-280, wherein the refractory ceramic fiber mats are subjected to waterproof treatment; wherein a first refractory ceramic fiber mat 23 with the thickness of 10mm is stuck on the lower surface of the prefabricated module bottom plate, a second refractory ceramic fiber mat 25 with the thickness of 6mm is stuck on the exposed part of the suspension cylinder, a third refractory ceramic fiber mat 24 with the thickness of 10mm is stuck on the lower surfaces of the first layer of bricks ZA-5686-N, DS 601-280 and DS 600-280, and a fourth refractory ceramic fiber mat 26 with the thickness of 10mm is stuck between the suspension cylinder and the first layer of bricks DS 601-280 and DS 600-280. This embodiment adopts refractory ceramic fiber pad to carry out effective parcel to hanging jar bottom steel construction, not only reduces the heat transfer but also reduces refractory material and the different resistant material life-span that leads to of steel construction coefficient of expansion and shortens, prolongs the life of the prefabricated module after changing greatly.

5) Respectively erecting a formwork according to the size of the unit plate with the prefabricated module removed, and separating the unit plate with the prefabricated module removed from the unit plate without the prefabricated module removed by using a partition plate; wherein each unit plate is independently supported by a mold, the mold is made of engineering plates, and the partition plates between the unit plates are made of thin steel plates.

6) As shown in fig. 3, the unit plates (shown as

unit plates

2, 4, 6, 8, 10 and 12) which are already supported are poured in sequence, the pouring material flows into the die from holes at two ends of the die, is compacted by vibration of a vibration rod, has no honeycomb holes, and is discharged until the upper die opening is leveled by vibration and the air is exhausted basically completely; as shown in fig. 4, there is shown a schematic cross-sectional structure along line a-a of fig. 3, in which a casting body 21 formed by solidifying a casting material is filled in a mold formed by each unit plate and covers all anchoring members 22, and the original MSS ramming material is also changed to the casting material to be integrated with the casting body under the bottom plate of the prefabricated module. The castable changes the low-cement pouring material which is the main material of the original imported precast module into mullite steel fiber castable, wherein the addition amount of the steel fiber is not less than 1% based on the total weight of the castable, and the castable can increase the thermal shock stability and reduce the generation of microcracks, thereby greatly prolonging the service life.

7) After the casting materials in the unit plate 2, the unit plate 4, the unit plate 6, the unit plate 8, the unit plate 10 and the unit plate 12 are solidified, the prefabricated modules in the residual unit plate 1, the residual unit plate 3, the residual unit plate 5, the residual unit plate 7, the residual unit plate 9, the residual unit plate 11 and the residual unit plate 13 and all the refractory materials on the prefabricated modules are removed, the prefabricated module bottom plates are reserved, and meanwhile, the damaged anchoring parts are removed.

8) Detaching the partition board in the step 5), and adhering a refractory ceramic fiber mat to the original partition board, wherein the thickness of the refractory ceramic fiber mat is 6 mm.

9) And (5) repeating the steps 2) to 6), and finishing the casting of all 13 unit plate blocks to obtain 13 cast bodies.

10) Curing the solidified casting body, then removing the mold, and performing edge cutting treatment to ensure that the casting body is smooth and has no convex-concave defects, simultaneously checking the size of an expansion joint, controlling the size to be 5-6mm, and if the size is too large, treating the casting body, and repairing the casting body by using a fine-grain casting material; if the size is too small, the size is enlarged by a cutting machine; and checking whether the suspension cylinder has missing pouring and missing edges and corners.

11) Baking the casting body with qualified inspection requirements, wherein the baking in the step is two-stage baking, the first-stage baking aims at removing free water of the internal structure part of the casting body, and the second-stage baking aims at removing combined water of the internal structure part of the casting body;

wherein, the first stage baking adopts an electric heating plate for drying and heating, and 20 electric heating plates with 400 x 200mm and 2000W rated power are purchased according to the size of a hanging cylinder, and 20 electric heating plates are purchased in each chamber. A temporary platform is built 550mm away from the bottom of the casting material of the suspension cylinder, and a refractory fiber felt is used for surrounding and blocking the casting material to be baked to form a closed annular area. Evenly put the electric plate on the platform before the annular region seals, two insulating bricks are filled up to the electric plate low part, and the electric plate lead wire is drawn out from the outer wall (reserves the pin hole when building the outer wall), for wire fusing when preventing high temperature, the lead wire that gets into the annular region will be protected with ceramic bushing. Two 400 ℃ digital temperature measuring instruments are connected to each chamber outside the castable expansion joint of the suspension cylinder so as to monitor the temperature conveniently. The baking time is about 3 days, a group of electric heating plates are firstly opened in each chamber, the temperature change condition is observed, and if the temperature is slowly increased, a group of electric heating plates are additionally opened; wherein the temperature is controlled within 120 ℃ on the first day, within 200 ℃ on the second day and within 250 ℃ on the third day. The first stage baking temperature rise control is specifically shown in fig. 5: the heating rate in the range of 110 ℃ or less is 8 ℃/h to 12 ℃/h, preferably 10 ℃/h, the temperature is set at a constant temperature for 110 ℃, for example, 25h to 30h, the heating rate in the range of 110 ℃ to 250 ℃ is 5 ℃/h, and the temperature is set at a constant temperature for 250 ℃, for example, 6h to 10 h.

The second stage of baking adopts a method of opening the Maerz kiln and igniting the Maerz kiln, the temperature environment of the Maerz kiln and igniting the Maerz kiln can be used for removing the bonding water of the internal structure part of the casting body, the temperature of the Maerz kiln and igniting the Maerz kiln can be ensured, two purposes are achieved, and the high-temperature baking procedure of the casting body is simplified. The ignition kiln scheme is well known to those skilled in the art, and may refer to the ignition kiln scheme provided by malz corporation, as shown in fig. 6, the baking time is 3 days, the temperature is increased to 600 ℃ at a certain temperature increasing rate on the first day, the temperature is kept at 600 ℃ for 24 hours on the second day, and the temperature is increased to 900 ℃ at a certain temperature increasing rate from 600 ℃ on the third day. However, the inventor finds that the ignition kiln drying scheme provided by the malz company cannot meet the repairing method of the invention, so that the repaired prefabricated module has poor use effect, and the inventor provides a new ignition kiln drying scheme through creative efforts, wherein the baking time is 5 days, the temperature on the first day is controlled within 300 ℃, the temperature on the second day is controlled within 400 ℃, the temperature on the third day is controlled within 600 ℃, the temperature on the fourth day is controlled within 700 ℃, and the temperature on the fifth day is controlled within 900 ℃. As shown in fig. 7, which shows an ignition kiln solution suitable for the present invention, the temperature control of the second stage baking is specifically: the temperature rise rate is 12.5 ℃/h within the range of less than or equal to 400 ℃, the constant temperature is set for 400 ℃, the temperature rise rate is 10 ℃/h within the range of 400 ℃ to 600 ℃, the constant temperature is set for 600 ℃, the temperature rise rate is 12.5 ℃/h within the range of 600 ℃ to 900 ℃, and the constant temperature is set for 900 ℃; the time set at the constant temperature of 400 ℃ is 20h, the time set at the constant temperature of 600 ℃ is 16h, and the time set at the constant temperature of 900 ℃ is 8 h.

The repairing method for the prefabricated module at the bottom of the suspension cylinder of the Mailz lime kiln, which is provided by the technical scheme in the embodiment, not only has the service life far exceeding that of an imported prefabricated module, but also has the construction and material cost greatly lower than that of the imported module, the service life is prolonged from 15 months to 60 months, the capital can be saved by 647.04 ten thousand yuan only from the material cost and the construction cost, the kiln shutdown caused by two times of maintenance is reduced for 60 days, and the production shutdown loss is avoided by 297.68 ten thousand yuan. The method of the embodiment can be popularized and applied to three steel-clad suspension cylinder wheat kilns, can be popularized to all suspension cylinder wheat kilns with similar structures in China, can bring a new way for the localization of spare parts of production units in the same industry, and is significant.

In conclusion, the cast-in-place method designed and developed by the invention replaces an imported Maerz kiln suspension cylinder bottom prefabricated module, not only exceeds the imported prefabricated module in service life, but also has construction and material costs greatly lower than the imported module costs, and is worthy of popularization in the Maerz kilns with the same structure nationwide.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A repair method of a prefabricated module at the bottom of a Maerz lime kiln suspension cylinder is disclosed, wherein the bottom of the Maerz lime kiln suspension cylinder comprises 52 prefabricated modules, and is characterized in that 4 adjacent prefabricated modules are divided into a unit plate, 13 unit plates in total and sequentially named as unit plates 1-13; wherein the repair method comprises the following steps:

2. A method according to claim 1, characterized in that in step 4) a 10mm thick mat of refractory ceramic fibres is applied to the lower surface of the prefabricated module floor, a 6mm thick mat of refractory ceramic fibres is applied to the exposed part of the suspension cylinder, and a 10mm thick mat of refractory ceramic fibres is applied to the lower surface of the first layer of bricks ZA-5686-N, DS 601-280 and DS 600-280.

3. The method according to claim 1 or 2, characterized in that the castable material in step 6) is a mullite steel fiber castable material, wherein the amount of steel fiber added is not less than 1% based on the total weight of the castable material.

4. The method according to any one of claims 1 to 3, wherein the baking in step 11) is a two-stage baking, wherein the first stage baking is aimed at removing free water from the internal structural part of the cast body and the second stage baking is aimed at removing bound water from the internal structural part of the cast body.

5. The method of claim 4, wherein the first stage baking is performed by hot plate baking for 3 days, wherein the temperature is controlled within 120 ℃ on the first day, within 200 ℃ on the second day, and within 250 ℃ on the third day.

6. The method according to claim 5, wherein the first stage baking temperature rise control is specifically: the heating rate is 8 ℃/h-12 ℃/h within the range of less than or equal to 110 ℃, the constant temperature is set for a time at 110 ℃, the heating rate is 5 ℃/h within the range of 110 ℃ to 250 ℃, and the constant temperature is set for a time at 250 ℃; wherein the constant temperature setting time at 110 ℃ is 25h-30h, and the constant temperature setting time at 250 ℃ is 6h-10 h.

7. The method as claimed in claim 4, wherein the second stage baking is performed by firing a Maerz kiln for 5 days, wherein the temperature is controlled within 300 ℃ on the first day, within 400 ℃ on the second day, within 600 ℃ on the third day, within 700 ℃ on the fourth day, and within 900 ℃ on the fifth day.

8. The method according to claim 7, wherein the temperature control of the second stage baking is specifically: the temperature rise rate is 12.5 ℃/h within the range of less than or equal to 400 ℃, the constant temperature is set for 400 ℃, the temperature rise rate is 10 ℃/h within the range of 400 ℃ to 600 ℃, the constant temperature is set for 600 ℃, the temperature rise rate is 12.5 ℃/h within the range of 600 ℃ to 900 ℃, and the constant temperature is set for 900 ℃; the time set at the constant temperature of 400 ℃ is 20h, the time set at the constant temperature of 600 ℃ is 16h, and the time set at the constant temperature of 900 ℃ is 8 h.