CN115585664A - Method for repairing bottom of annular heating furnace - Google Patents
Method for repairing bottom of annular heating furnace Download PDFInfo
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- CN115585664A CN115585664A CN202211432937.7A CN202211432937A CN115585664A CN 115585664 A CN115585664 A CN 115585664A CN 202211432937 A CN202211432937 A CN 202211432937A CN 115585664 A CN115585664 A CN 115585664A
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- pouring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/0043—Floors, hearths
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/12—Casings; Linings; Walls; Roofs incorporating cooling arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D2001/0046—Means to facilitate repair or replacement or prevent quick wearing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- General Engineering & Computer Science (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
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Abstract
The invention relates to the field of heating furnace repair, in particular to a method for repairing a furnace bottom of an annular heating furnace. The repairing method comprises the following steps: cooling in the furnace, controlling the temperature to be 300-800 ℃, blowing at the bottom of the furnace, and cleaning residues; pumping, pouring and furnace bottom rotation are combined, and pouring materials are poured into the groove material level of the furnace bottom; curing and heating are carried out after pouring; wherein, the pouring adopts a pouring manipulator which moves from one end of the groove to the other end at a variable speed within the range of 0-1 m/s along the plane vertical to the discharging port, the furnace bottom is rotated at the rotating speed of 1-2 min/material level, and the rotating direction of the furnace bottom is rotated from the discharging furnace door to the feeding furnace door. The method is used for repairing the furnace bottom of the annular heating furnace, can reduce maintenance cost and time, can quickly and effectively prolong the service life of the furnace bottom, improves the heating efficiency and quality of the billet, reduces the heating energy consumption and lightens the operation difficulty.
Description
Technical Field
The invention relates to the field of heating furnace repair, in particular to a method for repairing a furnace bottom of an annular heating furnace.
Background
In the use process of the annular heating furnace, the bottom of the furnace can form a groove-shaped material level after a period of use. This kind of material level can continuously deepen along with live time, can also play the effect that prevents to roll steel at first, nevertheless along with the recess deepens, can finally influence the heating efficiency and the effect of cylindrical steel billet, makes the steel billet heating unable reach the requirement even, leads to blowing out.
For the above groove type material level, there are three main maintenance modes at present: firstly, blowing out the furnace, integrally removing the bottom of the furnace and pouring again; secondly, filling magnesia particles in the grooves in a thermal state manually; thirdly, adopting a filling material compacting mode to repair.
However, the above-mentioned repair techniques for the furnace bottom of the annular heating furnace have various problems. The whole furnace is shut down, the bottom of the furnace is removed and the furnace is poured again, and the mode has long construction period and high cost. The magnesia in the filling magnesia method easily falls into the water seal tank, the damage of the water seal tank is accelerated, the workload of cleaning the water seal tank is increased, the magnesia needs to be repeatedly added in the method, and the cost is high. The press repairing method has the defects of low construction speed, complex operation of a plurality of processes of material scattering and material pressing, serious organic matter combination pollution and high overall cost.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for repairing the bottom of an annular heating furnace.
The invention provides a method for repairing the bottom of an annular heating furnace, which comprises the following steps: cooling in the furnace, controlling the temperature to be 300-800 ℃, blowing at the bottom of the furnace, and cleaning residues; pumping, pouring and furnace bottom rotation are combined, and pouring materials are poured into the groove material level of the furnace bottom; curing and heating are carried out after pouring; wherein, the pouring adopts a pouring manipulator, the pouring manipulator moves from one end of the groove to the other end of the groove at a variable speed within the range of 0-1 m/s along the plane vertical to the discharging port, the furnace bottom rotates at the rotating speed of 1-2 min/material level, and the rotating direction of the furnace bottom rotates from the discharging furnace door to the feeding furnace door.
The method for repairing the bottom of the annular heating furnace is formed by combining the pouring manipulator with the rotation control of the bottom of the annular heating furnace and matching the heat preservation and temperature rise technology in the furnace. The method needs short shutdown time, and the production can be recovered within 24 hours at the bottom of a common large heating furnace; the blowing-out requirement is low, the furnace temperature is generally controlled to be lower than 800 ℃, part of burners can be opened to maintain the furnace temperature during the material pouring period, the whole body is oxidized for 2 hours after the material pouring is finished, and the normal production can be realized through the shortest 4-hour temperature rise.
According to the method for repairing the bottom of the annular heating furnace, provided by the invention, continuous wet pumping is adopted for pumping, and the fluidity of the castable is 160-250.
The continuous wet pumping refers to that the casting material is uniformly mixed in advance and then is placed in a pumping bin, and the material is always stored in the pumping bin, so that the continuity of construction is ensured. It will be appreciated that it is also permissible for the pumping process to require brief pauses or interruptions for some onsite reason. Compared with the common castable conveying technology, the continuous wet pumping construction speed is high and can reach 8-20 tons/hour. The continuous wet pumping has strong terrain-crossing complex factor capability, continuous material pumping, no pouring pause and no material layering.
The pumping equipment in the invention adopts a pumping machine, which is a machine for continuously conveying refractory materials along a pipeline by using pressure. The cooling device is composed of a pump body and a delivery pipe, and is structurally in a piston type, wherein the part of the delivery pipe entering a furnace needs to adopt a winding refractory fiber blanket, a water-cooling or air-cooling structure and measures.
According to the method for repairing the furnace bottom of the annular heating furnace, provided by the invention, the castable comprises the following raw materials in percentage by weight:
20 to 50 percent of mullite
20 to 35 percent of alumina
10 to 25 percent of corundum
2 to 5 percent of swelling agent
4 to 8 percent of silicon micropowder
3 to 6 percent of alumina micro powder
2-3% of pure calcium aluminate cement
5-15% of B20 inorganic resin, wherein the B20 inorganic resin is added, and the weight percentage of the B20 inorganic resin is based on the sum of other raw materials.
According to the castable provided by the invention, al in the B20 inorganic resin 2 O 3 0-60% of SiO 2 The weight percentage content of the components is 0-50 percent,and Al 2 O 3 And SiO 2 The weight percentage of the components is not 0 at the same time.
According to the castable provided by the invention, the mullite is prepared from four grain sizes of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to the weight ratio of 2:10:5: 5. The mullite is particles produced by sintering or electric melting process, wherein Al is contained in the particles 2 O 3 50-70% of Fe 2 O 3 0.5-2.5% of SiO 2 The weight percentage of the components is 25-45%.
According to the castable provided by the invention, the alumina is prepared from four particle size grades of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to the weight ratio of 2:10:5: 5. The bauxite is a particle produced by a sintering process, wherein Al is 2 O 3 60-90% of Fe 2 O 3 0.5-2.5% of SiO 2 The weight percentage of the components is 15-40%.
According to the castable provided by the invention, the corundum is prepared from four particle size grades of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to the following weight ratio of 2:10:5: 5. The corundum is particles produced by sintering or electric melting process, including but not limited to brown corundum, white corundum, tabular corundum, compact corundum and the like, wherein Al is 2 O 3 The weight percentage content of the composite material is 90-99.9%.
According to the pouring material provided by the invention, the granularity of the expanding agent is 30-200 meshes, wherein Al 2 O 3 0-60% of SiO 2 The weight percentage of the components is 40-99.9%. The expanding agent includes, but is not limited to, sillimanite, andalusite, kyanite, quartz powder, etc.
According to the castable provided by the invention, siO in the silica micropowder 2 The weight percentage of the component is 90-96%. Al in the alumina micro powder 2 O 3 The weight percentage of the composite material is more than 99 percent.
The castable prepared from the raw materials is a self-flowing anti-explosion and anti-slag castable, has high self-flowing performance, the self-flowing value is more than 160mm, the castable can be constructed at the temperature of 800 ℃, the fluidity is maintained for more than 5 minutes at the temperature of 800 ℃, the pumping construction performance is good, the castable has the self-pore-forming anti-explosion characteristic at high temperature, the castable does not burst after construction, the adhesion with the furnace bottom is strong, the heavy pressure of a steel billet at the furnace bottom and the corrosion of maintenance iron can be met, and the service life of the castable can reach more than 6 months.
According to the method for repairing the furnace bottom of the annular heating furnace, the pouring height of the pouring material in the groove is 0-100mm higher than the furnace bottom.
According to the method for repairing the furnace bottom of the annular heating furnace, 1 expansion joint with the thickness of 3-20mm and the height of 20-200mm is installed or reserved at the position of the groove with the interval of 1-5. The expansion joint can be made of combustible materials or compressible materials such as PVC, wood, refractory fibers and the like. The expansion joint during high-temperature construction should resist 800 ℃ and keep the shape unchanged.
According to the method for repairing the bottom of the annular heating furnace, the maintenance condition is that the furnace is continuously rotated for 2-6 hours according to the pouring time direction according to the rotating speed of 1-2 minutes per material level.
According to the method for repairing the bottom of the annular heating furnace, the temperature is raised according to 100-200 ℃/hour, and the steel billet can be placed after the temperature reaches 800 ℃.
In some embodiments of the invention, the repair method comprises the steps of:
step one, temperature reduction and control in a furnace: after the billet is taken out of the furnace and heating is stopped, closing the burners, opening a furnace door and an access hole for ventilation and cooling for at least 4-6 hours, uniformly opening the high-temperature section burners when the furnace temperature is reduced to be below 800 ℃, keeping the furnace temperature at a certain temperature between 300 ℃ and 800 ℃ stably, wherein the flame length is less than 1 meter;
step two, blowing and supporting the mold at the furnace bottom: blowing and cleaning iron oxide, magnesia and refractory materials on the surface of the furnace bottom during the period of blowing out and cooling, and supporting molds at the low-lying positions at the two ends of the groove of the furnace bottom after cleaning to fill up thermal-state plug materials;
step three, setting a manipulator: a pouring manipulator is arranged at the central position of a furnace door at the discharge end of the annular furnace, an adjusting manipulator is perpendicular to the plane of the discharge port and freely runs at the speed of 0-1 m/s, and a debugging pump material outlet can be poured to the farthest position and the nearest position of the furnace bottom;
step four, rotationally arranging the furnace bottom: setting the rotating speed of the furnace bottom to be 1-2 minutes/material level, and pausing;
step five, hot pouring: the pouring material is stirred, the fluidity reaches 160-250, the pouring material is pumped by a pump, the pouring material is conveyed into a pipeline of a manipulator through a pipeline with the length of 10-150 meters, the pouring material is conveyed into the material level of a groove in the furnace bottom by moving the manipulator back and forth, the manipulator is aligned with the central position of the groove in the furnace bottom and slowly moves from one end of the groove to the other end of the groove, the furnace bottom is rotated towards the end of the feeding direction at the rotating speed of 1-2 minutes/material level, the manipulator gun head is enabled to face the center of the next material level to be continuously pumped from one end of the groove to the other end of the groove, the furnace bottom is rotated in the same direction to move for pouring, the pouring height of the pouring material is 0-100mm higher than that of the furnace bottom until the pouring is finished, and 1 expansion gap with the thickness of 3-20mm and the height of 20-200mm is arranged or reserved at every 1-5 material levels;
step six, maintenance: the poured furnace bottom gradually dehydrates and hardens along with the rotation of the furnace bottom during the pouring period, and after the pouring is finished, the furnace bottom continuously rotates for 2 to 6 hours according to the pouring time direction at the rotating speed of 1 to 2 minutes per material level;
step seven, temperature rising: the temperature is raised according to 100-200 ℃/hour, and the billet can be placed after 800 ℃.
By adopting the method, the maintenance time is short, and the repair time of the furnace bottom is reduced to 12-48 hours. The service life of the single thermal state maintenance material reaches 6-12 months.
Furthermore, in the second step, whether the mold is supported or not can be determined according to the furnace side condition, and when the furnace side condition is better, the mold support can be omitted. Specifically, when the frame brick has no defect or the length of single defect is not more than 0.5 m, and the total defect rate is less than or equal to 5%, the furnace edge condition is considered to be better.
Furthermore, in the third step, the mechanical arm is a suspended mechanical arm with a water cooling structure, can be installed and carried with a pumping pipeline and can freely advance through the operation of a remote controller. The manipulator can freely move forward and backward by more than 5 meters. The manipulator can realize normal use at the temperature of 800 ℃. Preferably, the manipulator is also provided with a temperature measuring device, so that the material temperature and the furnace temperature can be detected in real time. The viscosity of the material (casting material) can be detected by a viscometer arranged in a manipulator discharge pipe, and the material discharge flow state can be adjusted by feedback or manual regulation of a control system. The flow value of the material at high temperature is controlled between 160 and 220 for optimal construction conditions.
Furthermore, in the sixth step, the fluidity is adjusted during pouring according to the temperature condition in the furnace, so that the furnace bottom material is naturally flattened, and when the pouring material is transferred to the next manhole or the furnace door, tools such as a long-handle spatula are adopted to assist in leveling when the pouring material is not level.
The invention provides a method for repairing the bottom of an annular heating furnace, which comprises the important steps of bottom cleaning, castable pumping, bottom rotation control and pouring manipulator cooperative control, heat preservation and temperature rise in the furnace and the like. The method is used for repairing the furnace bottom of the annular heating furnace, can reduce maintenance cost and time, can quickly and effectively prolong the service life of the furnace bottom, improves the heating efficiency and quality of the billet, reduces the heating energy consumption and lightens the operation difficulty.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Unless otherwise specified, the starting materials for the examples of the present invention are commercially available.
In the following examples, the mullite is prepared from four grain sizes of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to the weight ratio of 2:10:5: 5. The mullite is a particle produced by a sintering process, wherein Al is contained in the mullite 2 O 3 50-70% of Fe 2 O 3 0.5-2.5% of SiO 2 The weight percentage of the components is 25-45%.
The bauxite is prepared from four particle size grades of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to the weight ratio of 2:10:5: 5. The bauxite is a particle produced by a sintering process, wherein Al is 2 O 3 Occupied weight60-90% of Fe 2 O 3 0.5-2.5% of SiO 2 The weight percentage of the components is 15-40%.
The corundum is prepared from four particle size grades of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to the weight ratio of 2:10:5:5, the components are mixed. Wherein Al is 2 O 3 The weight percentage of the component is 90-99.9%.
The particle size of the expanding agent is 30-200 meshes, wherein Al 2 O 3 0-60% of SiO 2 The weight percentage of the components is 40-99.9%.
SiO in silica micropowder 2 The weight percentage of the component is 90-96%.
Al in alumina micropowder 2 O 3 The content of the active ingredients is 99 percent by weight.
Al in B20 inorganic resin 2 O 3 0-60% of SiO 2 0-50% by weight of Al 2 O 3 And SiO 2 The weight percentage of the components is not 0 at the same time.
Example 1
The embodiment provides a method for repairing the bottom of an annular heating furnace, which comprises the following specific steps:
step one, a 38-meter annular furnace is used for sweeping the bottom of the furnace in advance (the bottom of the furnace starts to sweep one day before blowing out, the condition of the furnace edge is better, a formwork is not supported), steel billets are discharged completely in advance, a burner is closed in the furnace to stop heating, and a charging furnace door and an access hole are opened to carry out ventilation and cooling for at least 4 hours. The furnace temperature is reduced to 620-780 ℃, the high-temperature section burner is opened uniformly, the flame length is 0.5 m, and the furnace temperature of the high-temperature section is stably maintained at 550 ℃.
And secondly, installing a pouring manipulator at the center of a furnace door at the discharge end of the annular furnace, adjusting the manipulator to freely run at a speed of 0-1 m/s perpendicular to the plane of the discharge end, and adjusting a pump material outlet to pour the material to the farthest and the nearest parts of the furnace bottom.
And step three, setting the rotation of the furnace bottom, namely, adopting a steering wheel type handheld remote control to operate the rotation of the furnace bottom, setting the rotation speed of the furnace bottom to be 1-2 minutes/material level, and pausing.
And step four, performing thermal state pouring, wherein after the thermal state pouring material is properly stirred by a stirrer, the fluidity reaches 180, the thermal state pouring material is pumped by a pumping machine, conveyed into a manipulator pipeline through a pipeline with the diameter of 100mm and the length of about 25 m, and pumped into a groove at the bottom of the construction site furnace through the back-and-forth movement of the manipulator. The average casting height of the pumping material is 70mm, 1 refractory fiber with the thickness of 5mm and the height of 70mm is arranged at every 3 material positions as an expansion joint, and a three-ply board is adopted to support and fix the expansion joint. And naturally flattening the furnace bottom castable.
The formula of the thermal-state castable is as follows:
50 percent of mullite
Alumina 20 percent
Dense corundum 10%
Andalusite 5%
8 percent of silicon micropowder
5 percent of alumina micro powder
2 percent of pure calcium aluminate cement
And B20 inorganic resin 10%.
And step five, after the pouring is finished, the furnace bottom is still rotated for 6 hours according to the pouring time direction according to 1-2 minutes/material level for maintenance.
And step six, heating, namely heating according to the temperature of 100 ℃ per hour. The steel billet can be placed after 800 ℃.
The total construction period of the repairing method of the embodiment is 24 hours. The service life of the furnace bottom of the heating furnace is one year after the repair. Wherein, the hot state pouring layer is completely worn through by 70mm as in the embodiment, the heating condition of the furnace bottom billet is deteriorated to the level before construction, and the furnace bottom needs to be maintained again.
Example 2
The embodiment provides a method for repairing the bottom of an annular heating furnace, which comprises the following specific steps:
step one, a 42-meter annular furnace is stopped due to an accident, steel billets cannot be normally delivered, the steel billets are gradually delivered after the furnace is stopped, the temperature of the furnace is controlled by a high-temperature section, the whole furnace is in a cooling state, the time for discharging the steel billets is 20 hours, a furnace door and an access hole are opened during the period for ventilating and cooling, the whole low-temperature section of the furnace is reduced to 200-300 ℃, high-temperature section burners are uniformly opened after the steel billets are discharged, the flame length is 0.8 meter, and the furnace temperature is stably maintained at 450 ℃.
And step two, synchronously carrying out furnace bottom sweeping and formwork support during the steel tapping period. And (4) after cleaning, supporting a mold at the low-lying positions at two ends of the groove in the furnace bottom, and filling 2 tons of thermal-state plugging materials.
And step three, mounting a pouring manipulator at the center of a furnace door at the discharge end of the annular furnace, adjusting the manipulator to freely run at a speed of 0-1 m/s perpendicular to the plane of the discharge end, and adjusting a pump material outlet to pour the material to the farthest and the nearest parts of the furnace bottom.
And step four, furnace bottom rotation setting, namely, the furnace bottom rotation is operated by adopting a hand-held key type remote control, the furnace bottom rotation speed is set to be 1-2 minutes/material level, and the operation can be stopped.
And fifthly, performing thermal state pouring, wherein after the thermal state pouring material is stirred properly by a stirrer, the fluidity reaches 220, the pouring material is pumped by a pumping machine, conveyed into a manipulator pipeline through a pipeline with the diameter of 100mm and the length of 35 m, and pumped into a groove at the bottom of the construction site to be poured by a manipulator moving back and forth. The average casting height of the pumped materials is 50mm, and PVC expansion gaps with the thickness of 5mm and the height of 50mm are installed at every 5 material positions during tapping.
The formula of the thermal-state castable is as follows:
mullite 35%
20 percent of alumina
Corundum 25%
Andalusite 5%
8 percent of silicon micropowder
5 percent of alumina micro powder
2 percent of pure calcium aluminate cement
And 9% of B20 inorganic resin.
And step six, maintaining at the bottom of the furnace, and continuing to rotate for 4 hours in the pouring direction according to 1-2 minutes/material level.
And step seven, heating according to 200 ℃/hour. The billet can be put after 800 ℃.
The total construction period of the repairing method of the embodiment is 40 hours (including tapping 20 hours). The service life of the furnace bottom of the heating furnace is 1 year after the repair.
Example 3
The embodiment provides a method for repairing the bottom of an annular heating furnace, which comprises the following specific steps:
step one, 36 m of annular furnace, stopping heating when the billet is discharged out of the furnace, closing a burner, opening a furnace door and an access hole, and ventilating and cooling for at least 4 hours. When the furnace temperature is reduced to below 800 ℃, uniformly opening the high-temperature section burner, wherein the flame length is 0.9 m, and stably maintaining the furnace temperature at 800 ℃.
And step two, blowing the furnace bottom, wherein the furnace temperature is high and the mold is not supported.
And step three, installing a pouring manipulator at the center of a furnace door at the discharge end of the annular furnace, wherein the speed of the manipulator is not adjusted.
And step four, the rotation of the furnace bottom is not set, a discharging furnace door constructor communicates with a master control room through an interphone to operate the rotation of the furnace bottom, the rotation speed of the furnace bottom is set to be 3 m/s, and the furnace bottom can be stopped and retreated.
And fifthly, performing thermal state pouring, wherein after the thermal state pouring material is stirred properly by a stirrer, the fluidity reaches 220, the thermal state pouring material is pumped by a pumping machine, conveyed into a manipulator pipeline through a pipeline with the diameter of 100mm and the length of 20m, and pumped to a groove at the bottom of the construction site for pouring by the back and forth movement of the manipulator. The planned height of the pumped material pouring is 50mm, and 1 refractory fiber expansion joint is installed or reserved at every 3 material positions. However, the speed of the manipulator is too high to reach 8 m/s because the speed of the manipulator is not adjusted, the manipulator cannot move at a constant speed, the manipulator can not move 1m at a short time, the material is not uniformly poured at the furnace bottom but is piled up, the furnace temperature is high, the pouring material cannot uniformly fill the material level, the material begins to lose fluidity after 3 minutes, the material spread out by a manual iron rake is loose when the furnace is not timely filled, and the loose material cannot be densely filled at the furnace bottom and only can be used as waste for cleaning and is difficult to clean. After the adjusting speed of the manipulator is 0.5 m/S, the rotating speed is too high when the furnace bottom is operated due to the fact that the furnace bottom is not adjusted, materials are poured into the furnace bottom in an S shape, grooves cannot be filled, and a large amount of materials are accumulated on one point when the furnace bottom is stopped due to the delay of operation of the interphone, so that the situation that the furnace bottom cannot be automatically flattened is caused. After 2 hours of debugging, normal operation is recovered. During the pouring stopping period, the furnace bottom material is naturally flattened due to the fact that the temperature in the furnace is high and the fluidity is adjusted to be high.
The formula of the thermal-state castable is as follows:
mullite 40%
20 percent of alumina
Corundum 20%
5 percent of swelling agent
8 percent of silicon micropowder
5 percent of alumina micro powder
2 percent of pure calcium aluminate cement
And 11% of B20 inorganic resin.
And step six, maintenance, wherein the poured furnace bottom gradually dehydrates and hardens along with the rotation of the furnace bottom during pouring.
And step seven, heating according to the speed of 150 ℃ per hour. The billet can be put after 800 ℃.
The total construction period of the repairing method is 12 hours, wherein 2 hours of delay is caused by adjusting the manipulator and the rotating speed of the furnace bottom, and 1 ton of material waste is caused. The furnace temperature reaches 800 ℃ during construction, and the addition amount of the material binding agent is increased from 11% to 13%. The service life of the furnace bottom of the heating furnace is 8 months after the repair.
Example 4
The embodiment provides a method for repairing the bottom of an annular heating furnace, which comprises the following specific steps:
step one, carrying out a 38-meter annular furnace, carrying out 7-day overhaul on the furnace, finding that part of furnace walls are seriously inclined after stopping the furnace, and dismantling the furnace walls with the height of 6 meters in the high-temperature section. And opening the furnace door and the access hole to perform ventilation and cooling during the period, and cleaning the furnace when the overall temperature of the furnace is reduced to below 100 ℃.
And step two, replacing the damaged frame brick. And blowing the furnace bottom to be clean. And (3) erecting a surrounding and blocking mould at low-lying positions at two ends of a groove in the furnace bottom and at positions for replacing frame bricks, and using 3 tons of thermal-state plugging materials. And (4) pouring the furnace wall.
And step three, mounting a pouring manipulator at the center of a furnace door at the discharge end of the annular furnace, adjusting the manipulator to freely run at a speed of 0-1 m/s perpendicular to the plane of the discharge end, and adjusting a pump material outlet to pour the material to the farthest and the nearest parts of the furnace bottom.
And step four, furnace bottom rotation setting, namely, the furnace bottom rotation is operated by adopting a hand-held key type remote control, the furnace bottom rotation speed is set to be 1-2 minutes/material level, and the operation can be stopped.
And fifthly, pouring at the furnace temperature of 100 ℃, after the thermal-state pouring material is properly stirred by a stirrer, the fluidity reaches 220, the pouring material is pumped by a pumping machine, conveyed into a manipulator pipeline through a pipeline with the diameter of 100mm and the length of 15 meters, and pumped into a groove at the bottom of the furnace at the construction part for pouring by the back-and-forth movement of the manipulator. The average casting height of the pumped materials is 70mm, and PVC expansion gaps with the thickness of 5mm and the height of 50mm are installed at every 5 material positions during tapping.
The formula of the thermal-state castable is as follows:
mullite 20%
35 percent of alumina
Corundum 25%
5 percent of swelling agent
8 percent of silicon micropowder
5 percent of alumina micro powder
2 percent of pure calcium aluminate cement
And B20, 8 percent of inorganic resin.
And step six, maintaining at the bottom of the furnace, and continuing to rotate for 4 hours in the pouring direction according to 1-2 minutes/material level.
And step seven, during construction of the furnace bottom, the temperature of the furnace bottom is reduced greatly due to maintenance of the furnace wall, and the situation that the surface of the material is firstly hardened and the center is not hardened occurs. In order to put into production as early as possible, partial burners are ignited to raise the temperature, so that the poured bottom of the furnace is rotated to the position of opening the burners, and 10-20mm of materials on the surface of the bottom of the furnace are cracked. Because the low not closed access door of furnace temperature has in time found the problem of bursting, reduces some burner flame length to 0.5 meters afterwards, opens 4 nozzles simultaneously more to evenly promote furnace temperature. After the construction is finished for 6 hours, the furnace temperature reaches 300 ℃, the poured furnace bottom rotates in the furnace for 3 weeks, and then the temperature is raised to 800 ℃ according to 100 ℃/hour. The billet can be put after 800 ℃. The temperature is raised to the production temperature according to 200 ℃/hour.
The construction period of the repairing method of the embodiment is 24 hours (no furnace shutdown and furnace wall repairing are included). The service life of the furnace bottom of the heating furnace is 1 year after the repair.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The method for repairing the bottom of the annular heating furnace is characterized by comprising the following steps of: cooling in the furnace, controlling the temperature to be 300-800 ℃, blowing at the bottom of the furnace, and cleaning residues; pumping, pouring and furnace bottom rotation are combined, and pouring materials are poured into the groove material level of the furnace bottom; curing and heating after pouring;
wherein, the pouring adopts a pouring manipulator which moves from one end of the groove to the other end at a variable speed within the range of 0-1 m/s along the plane vertical to the discharging port, the furnace bottom is rotated at the rotating speed of 1-2 min/material level, and the rotating direction of the furnace bottom is rotated from the discharging furnace door to the feeding furnace door.
2. The method for repairing the bottom of the annular heating furnace according to claim 1, wherein the pumping is performed by a continuous wet pumping, and the fluidity of the castable is 160-250.
3. The method for repairing the bottom of the annular heating furnace according to claim 2, wherein the castable comprises the following raw materials in percentage by weight:
20 to 50 percent of mullite
20 to 35 percent of alumina
10 to 25 percent of corundum
2 to 5 percent of swelling agent
4 to 8 percent of silicon micropowder
3 to 6 percent of alumina micro powder
2-3% of pure calcium aluminate cement
5-15% of B20 inorganic resin, wherein the B20 inorganic resin is added, and the weight percentage of the B20 inorganic resin is based on the sum of other raw materials.
4. The method for repairing a hearth of an annular heating furnace according to claim 3, wherein Al in the B20 inorganic resin is 2 O 3 Occupied weight0-60% of SiO 2 0-50% by weight of Al 2 O 3 And SiO 2 The weight percentage of (A) is not 0 at the same time.
5. The method for repairing the hearth of the annular heating furnace according to claim 3, wherein the mullite, the alumina and the corundum are prepared from four grain sizes of 8-5mm, 5-3mm, 3-1mm and 1-0mm according to a weight ratio of 2:10:5:5, preparing a composition;
and/or the particle size of the expanding agent is 30-200 meshes, wherein Al 2 O 3 0-60% of SiO 2 The weight percentage of the components is 40-99.9%.
6. The method for repairing the hearth of the annular heating furnace according to claim 1, wherein the casting height of the casting material in the groove is 0-100mm higher than the hearth.
7. The method for repairing the hearth of the annular heating furnace according to claim 1, wherein 1 expansion joint with the thickness of 3-20mm and the height of 20-200mm is installed or reserved at the position of the groove with the interval of 1-5.
8. The method for repairing a hearth of an annular heating furnace according to claim 1, wherein the maintenance is performed under the condition that the hearth is continuously rotated in the casting time direction at a rotation speed of 1 to 2 minutes per material level for 2 to 6 hours.
9. The method for repairing the bottom of the annular heating furnace according to claim 1 or 8, wherein the temperature is raised according to 100-200 ℃/hour, and the billet can be placed after the temperature reaches 800 ℃.
10. The method for repairing a hearth of an annular heating furnace according to claim 1, characterized by comprising the steps of:
step one, temperature reduction and control in a furnace: after the billet is taken out of the furnace and heating is stopped, closing the burners, opening a furnace door and an access hole for ventilation and cooling for at least 4-6 hours, uniformly opening the high-temperature section burners when the furnace temperature is reduced to be below 800 ℃, keeping the furnace temperature at a certain temperature between 300 ℃ and 800 ℃ stably, wherein the flame length is less than 1 meter;
step two, blowing and supporting the mold at the furnace bottom: blowing and cleaning iron oxide, magnesia and refractory materials on the surface of the furnace bottom during the period of blowing out and cooling, and supporting molds at the low-lying positions at the two ends of the groove of the furnace bottom after cleaning to fill up thermal-state plug materials;
step three, setting a manipulator: a pouring manipulator is arranged at the central position of a furnace door at the discharge end of the annular furnace, the adjusting manipulator is vertical to the plane of the discharge port and freely runs at the speed of 0-1 m/s, and a debugging pump material outlet can be poured to the farthest and the nearest parts of the furnace bottom;
step four, rotationally arranging the furnace bottom: setting the rotating speed of the furnace bottom to be 1-2 minutes/material level, and pausing;
step five, hot pouring: the pouring material is stirred, the fluidity reaches 160-250, the pouring material is pumped by a pump, the pouring material is conveyed into a pipeline of a manipulator through a pipeline with the length of 10-150 meters, the pouring material is conveyed into the material level of a groove in the furnace bottom by moving the manipulator back and forth, the manipulator is aligned with the central position of the groove in the furnace bottom and slowly moves from one end of the groove to the other end of the groove, the furnace bottom is rotated towards the end of the feeding direction at the rotating speed of 1-2 minutes/material level, the manipulator gun head is enabled to face the center of the next material level to be continuously pumped from one end of the groove to the other end of the groove, the furnace bottom is rotated in the same direction to move for pouring, the pouring height of the pouring material is 0-100mm higher than that of the furnace bottom until the pouring is finished, and 1 expansion gap with the thickness of 3-20mm and the height of 20-200mm is arranged or reserved at every 1-5 material levels;
step six, maintenance: after the pouring is finished, the furnace bottom continuously rotates for 2-6 hours according to the pouring time direction according to the rotating speed of 1-2 minutes/material level;
step seven, temperature rising: the temperature is raised according to 100-200 ℃/hour, and the billet can be placed after 800 ℃.
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