A method for overhauling a blast furnace hearth in a confined space

Abstract

The present invention relates to a confined space blast furnace hearth maintenance construction method, comprising: 1. hearth data detection, collecting temperature data of various points in the hearth to determine the maintenance, dismantling and restoration scope; 2. cleaning slag, sending the slag to the outside of the blast furnace after the blast furnace is in a safe range; 3. adding a first-stage reinforcement device, after the slag in the furnace is removed to a preset distance below the center line of the tuyere, sending the first-stage reinforcement device into the furnace for installation; 4. removing carbon bricks, after the first-stage reinforcement device is in place, removing the carbon bricks between the iron mouth and the retained carbon bricks, performing docking reinforcement of the second-stage reinforcement device, and removing the carbon bricks below the top surface of the residual iron; 5. cutting local residual iron, taking protective measures for carbon bricks on the bottom layer of the retained carbon bricks, and then cutting the residual iron; 6. removing carbon bricks at the edge of the retained carbon bricks, after the residual iron cutting is completed, removing the carbon bricks that need to be removed adjacent to the retained carbon bricks; 7. after the residual iron cutting and carbon brick removal are completed, grinding and cleaning the residues on the surface of the cooling wall; 8. laying new carbon bricks.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace hearth maintenance, and in particular to a blast furnace hearth maintenance construction method in a confined space. Background Art

[0002] The performance of refractory materials for blast furnace hearth is one of the key factors affecting the life of blast furnace. Due to the properties of carbon refractory bricks, they are widely used in the construction of blast furnace bottoms and hearths. In recent years, the scope of use has been continuously expanded, and carbon bricks have also begun to be used in the furnace belly and the lower part of the furnace body, which can increase the continuous operation time of the blast furnace and extend its service life. However, after the blast furnace has been put into operation for a period of time, the carbon bricks in the hearth will be damaged due to various reasons, which will in turn affect the service life of the blast furnace. The repair of carbon bricks for blast furnace maintenance has become an important measure to improve the life of the blast furnace. Conventional maintenance and construction methods can only alleviate the existing problems but cannot cure them. If a thorough cure is required, the hearth needs to be overhauled, and the cost and construction period far exceed this plan. In addition, the space in the blast furnace hearth is limited. How to efficiently and smoothly complete the repair work and ensure the construction quality of the carbon bricks in the hearth is particularly important. Therefore, a new blast furnace hearth maintenance plan is urgently needed. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for the maintenance of a blast furnace hearth in a confined space. This solution is understood to be the first in the world. It is a construction method for partially removing and restoring the ring carbon at the maintenance location in a limited space without placing residual iron and meeting the corresponding production requirements. The present invention includes the following steps:

[0004] Step 1: Detect the data of each point of the furnace, collect the temperature data of each point of the furnace to determine the scope of maintenance, removal and restoration;

[0005] Step 2: Clean the slag. After the blast furnace is cooled and the temperature, gas and oxygen concentrations are within a safe range, the slag is transported out of the furnace through the large square holes and tuyere on the top of the furnace;

[0006] Step 3: After the first section of the reinforcement device is added, the slag in the furnace is removed to a preset distance below the center line of the tuyere, and the first section of the reinforcement device is sent into the furnace through the large square hole on the top of the furnace and installed in place at the corresponding position;

[0007] Step 4: Remove the carbon bricks. After the first section of the reinforcement device is in place, first remove the carbon bricks above the iron mouth to the retained carbon bricks, then carry out the docking reinforcement of the second section of the reinforcement device, and finally remove the carbon bricks below the top surface of the residual iron;

[0008] Step 5: Cutting of local residual iron: First, take protective measures on the carbon bricks on the bottom layer, and then drill and cut the residual iron multiple times;

[0009] Step 6: Remove the carbon bricks at the edge of the retained carbon bricks. After the residual iron is cut, use a water drill to remove the carbon bricks that need to be removed that are adjacent to the retained carbon bricks;

[0010] Step 7: After the residual iron cutting and carbon brick removal are completed, the residual on the surface of the cooling wall is polished and cleaned, and then the foundation is leveled with the furnace casting material;

[0011] Step 8: Laying down new carbon bricks: Determine the elevation of new carbon bricks, and then lay them layer by layer.

[0012] Furthermore, in step 4, when removing the carbon bricks, a displacement sensor is installed at the bottom of the remaining carbon bricks. Specifically, by installing the displacement sensor, the remaining carbon bricks can be monitored in real time to ensure that no displacement occurs.

[0013] Furthermore, in step 4, when the overhanging size of the carbon bricks on both sides exceeds 2 / 3 of the width of the original carbon bricks, transverse supports are added for reinforcement. Specifically, the stability of the carbon bricks is further enhanced by the provided transverse supports, ensuring that the removal of the carbon bricks is carried out according to the plan.

[0014] Furthermore, in the step 4, the removal of the carbon bricks in the narrow area below the residual iron surface or in contact with the retained carbon bricks is carried out in coordination with the cutting of the residual iron.

[0015] Furthermore, in step seven, when the foundation is leveled, the upper surface of the castable should be level with the upper surface of the retained carbon brick in the radial direction. Specifically, the retained carbon brick has a certain amount of wear, and after the castable is leveled, it can be ensured that the laying thickness is flush with the original carbon brick or the newly laid carbon brick.

[0016] Furthermore, in step eight, the elevation of the newly laid charcoal bricks is controlled by the elevation of the upper surface of the retained charcoal bricks in the same layer, thick carbon mortar is used for the mortar joints of charcoal bricks less than or equal to 2 mm, and the fullness of the mortar in the joints is ensured, and special powder is used to fill the horizontal brick joints greater than or equal to 2 mm.

[0017] Furthermore, in step eight, when the penultimate layer of carbon bricks is laid, the maximum value of the closing brick that can enter from the side when all the new carbon bricks are retreated to the cooling wall surface is calculated, and the closing brick is designed as a wedge-shaped brick based on the maximum value, and is pushed in horizontally from the side when closing the door.

[0018] Furthermore, in step eight, the last layer of carbon bricks is built, and the carbon bricks in the non-door closing area are designed in two layers, the second layer is designed as small carbon blocks, and the height of the small carbon blocks is larger than the design value; the last layer of carbon brick door closing bricks is designed as all small carbon bricks, and is built layer by layer from the cooling wall direction into the furnace. Specifically, during the construction, the second layer of small carbon blocks is polished on site according to the actual situation, so that the small carbon blocks and the upper retained carbon bricks fit tightly.

[0019] Furthermore, in the step five, the brittle layer between the carbon bricks and the residual iron at the residual iron cutting position is removed, the cutting drilling position is determined according to the maximum weight of the residual iron lifting, and the residual iron is cut through the brittle layer gap and the drill hole.

[0020] Furthermore, in step eight, when laying new carbon bricks, a thermocouple is set at the junction of each layer of new and old carbon bricks.

[0021] In summary, the beneficial technical effects of the present invention are: creatively removing part of the carbon bricks in the furnace and replacing them with new carbon bricks, providing a new idea for the maintenance of the blast furnace hearth. The repair construction technology is safe and reliable, so that the maintenance work can be carried out smoothly and the construction quality of the furnace hearth carbon bricks is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used throughout the drawings to represent the same components; Figure 1 It is the overall construction process of the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0024] Reference Figure 1The above is a confined space blast furnace hearth maintenance construction method disclosed by the present invention, which includes step one, detecting data of each point in the hearth, collecting temperature data of each point in the hearth to determine the maintenance scope, removal scope, and restoration scope; step two, cleaning the slag, after the blast furnace is cooled and the temperature, gas, and oxygen concentration are within a safe range, the slag is sent out of the furnace through the large square hole on the furnace top and the tuyere; step three, adding the first section of the reinforcement device, after the slag in the furnace is scraped to a preset distance below the center line of the tuyere, the first section of the reinforcement device is sent into the furnace through the large square hole on the furnace top, and installed in place at the corresponding position; step four, removing the carbon bricks, after the first section of the reinforcement device is in place, first remove the iron mouth to Remove the carbon bricks between the retained carbon bricks, then carry out the docking reinforcement of the second section of the reinforcement device, and finally remove the carbon bricks below the top surface of the residual iron; Step 5, local residual iron cutting, first take protective measures for the carbon bricks on the bottom layer of retained carbon bricks, and then perform multiple drilling and cutting of the residual iron; Step 6, remove the carbon bricks on the edge of the retained carbon bricks, after the residual iron cutting is completed, use a water drill to remove the carbon bricks that need to be removed adjacent to the retained carbon bricks; Step 7, material beating and trimming, after the residual iron cutting and carbon brick removal are completed, grind, correct and clean the residues on the surface of the cooling wall, and then use the furnace castable to level the foundation; Step 8, lay new carbon bricks, determine the elevation of the new carbon bricks, and then lay them layer by layer.

[0025] The best embodiment is as follows

[0026] Step 1: Detect data at each point in the furnace, collect temperature data at each point in the furnace to determine the scope of maintenance, demolition and restoration. Specifically: (1) Estimate the thickness of the residual carbon bricks at each point based on the temperature of each point in the furnace collected during the production process, and determine the approximate scope of maintenance; (2) According to the scope of demolition, formulate a demolition method for partial demolition of carbon bricks. The demolition principle is to keep the carbon bricks from being damaged or displaced; (3) According to the scope of demolition of carbon bricks in the furnace, determine the reinforcement method for the retained carbon bricks. The reinforcement principle is to ensure that the retained carbon bricks are safe and do not sink; they should not affect other operations such as slag removal, residual iron cutting and lifting in the furnace; (4) The partial cutting method of residual iron, the cutting principle is to keep the carbon bricks from being damaged; the residual iron cutting range meets the space for new carbon bricks (including construction operation space); (5) According to the demolition scope, formulate the scope of carbon brick restoration, restoration quality standards, restoration quality control measures, etc.; (6) According to the maintenance content, sort out the connection between various professions and processes.

[0027] Step 2: Clean the slag. After the blast furnace is cooled and the temperature, gas and oxygen concentrations are within a safe range, the slag is sent out of the furnace through the large square holes on the furnace roof and the tuyere. Specifically: (1) Clean the slag. After the blast furnace is cooled, the temperature, gas concentration and oxygen concentration in the furnace are within a safe range. A small excavator is hoisted into the furnace through the large square hole on the furnace roof, and the slag is sent out of the furnace through the belt conveyor installed at the tuyere. (2) During the slag removal process, the slag and iron residues attached to the surface of the tuyere composite bricks and the carbon ring should be cleaned manually to expose the tuyere composite bricks and carbon bricks completely, but the refractory material itself should not be damaged. (3) While removing the slag from the furnace, remove the castables at the contact area between the main ditch and the outer iron mouth frame that need to be repaired, and then remove the iron mouth composite bricks from the outside to the inside; (4) The main ditch outside the furnace is equipped with a corresponding excavator to cooperate with the excavator inside the furnace to clean the slag in the furnace.

[0028] (5) Slag is scraped from the furnace to the upper surface of the residual iron in the furnace, and the slag on the upper surface of the residual iron is cleaned with a head-pulling machine until it can no longer be removed.

[0029] Step three, the first section of the reinforcement device is added. After the slag in the furnace is removed to a preset distance below the center line of the tuyere, the first section of the reinforcement device is sent into the furnace through the large square hole on the top of the furnace and installed in place at the corresponding position. Specifically, the first section of the reinforcement device is added. When the slag in the furnace is removed to a position about 1m below the center line of the tuyere, the first section of the carbon brick reinforcement device is sent into the furnace through the large square hole on the top of the furnace. The corresponding tuyere is located according to the position of the demolition and the first section of the reinforcement device is installed in place. The first section of the reinforcement device is used to reinforce the retained carbon bricks. In addition to ensuring the safety of the furnace, it can also ensure that the carbon bricks do not settle and ensure the quality of the blast furnace after the carbon bricks are restored.

[0030] Step 4, carbon brick removal. After the first section of the reinforcement device is in place, first remove the carbon bricks between the iron mouth and the retained carbon bricks, then carry out docking reinforcement of the second section of the reinforcement device, and finally remove the carbon bricks below the top surface of the residual iron. Specifically: (1) Principles of carbon brick removal: It is forbidden to use large machinery for removal. Appropriate use of pneumatic picks and electric picks for removal. Use water drills for drilling and removal operations near the retained carbon bricks; (2) Carbon bricks are removed from the iron mouth to the retained carbon bricks. The removal width is the width of two carbon bricks until the bottom of the retained carbon bricks. If the removal width is too wide, the upper carbon bricks are easy to sink. Then the second section of the reinforcement device that is transported to the furnace through the iron mouth is docked with the first section to reinforce the retained carbon bricks. After the first reinforcement is completed, the carbon bricks on both sides are removed according to the removal range, and they are reinforced in time during the removal process. After the entire reinforcement is completed, the reinforcement device is connected as a whole using angle steel to form a whole.

[0031] (3) To monitor the retained carbon bricks in real time, displacement sensors are installed at the bottom of the retained carbon bricks to monitor the retained carbon bricks in real time to ensure that no displacement occurs; (4) As the demolition range expands, when the cantilever size of the carbon bricks on both sides exceeds 2 / 3 of the original carbon brick width, lateral supports need to be added for reinforcement to prevent displacement; (5) Removal of carbon bricks below the top surface of the residual iron: remove the brittle layer between the carbon bricks and the residual iron, use a water drill to drill holes in one of the carbon bricks on the same layer (the carbon brick that is easy to remove) and then remove it with a pneumatic pick; for other carbon bricks on the same layer, remove the brittle layer at the front end and the ramming material at the rear end, and then remove them with a crowbar; the removed carbon bricks are lifted by a winch installed on the furnace top to a rail trolley and transported outside the furnace; (6) The removal of carbon bricks in narrow areas below the residual iron surface or in contact with the retained carbon bricks needs to be coordinated with the cutting of the residual iron.

[0032] Step 5: Cutting of local residual iron. First, take protective measures on the carbon bricks on the bottom layer of retained carbon bricks, and then drill and cut the residual iron multiple times. Specifically: (1) Determine the radial thickness of the residual iron cutting according to the size of the restored carbon bricks, the thickness of the protective layer castable and the construction operation space; determine the width of the residual iron cutting according to the range of the removed carbon bricks and the above-mentioned influencing factors; (2) In order to ensure the construction period, the amount of residual iron cutting should be minimized while ensuring the space, and the residual iron should be cut locally and protective measures should be taken for the retained carbon bricks; (3) The brittle layer between the carbon bricks and the residual iron at the cutting site needs to be removed for local residual iron cutting. The cutting drilling position is determined according to the maximum weight of the residual iron hoisting (each construction area requires multiple drilling and cutting to meet the construction requirements), and the rope saw cuts the residual iron through the gaps in the brittle layer and the drilled holes; (4) Before cutting the residual iron, take protective measures on the carbon bricks on the bottom layer of retained carbon bricks to prevent the retained carbon bricks from being damaged by the cut residual iron.

[0033] Step 6: Remove the carbon bricks that retain the edge of the carbon bricks. After the residual iron is cut, use a water drill to remove the carbon bricks that need to be removed that are adjacent to the retained carbon bricks.

[0034] Step 7: After the residual iron cutting and carbon brick removal are completed, the residual on the cooling wall surface is polished and cleaned, and then the foundation is leveled with furnace casting material. Specifically:

[0035] (1) Prepare for the reinstallation of carbon bricks by beating and trimming the materials. After the residual iron cutting and carbon brick removal are completed, the residue on the surface of the cooling wall is polished, and the ramming materials between the carbon bricks and the cooling wall are trimmed to create conditions for the reinstallation of the carbon bricks. (2) After the cleaning is completed, the foundation is leveled with the furnace castable. The upper surface of the castable should be level with the upper surface of the retained carbon bricks in the radial direction (the retained carbon bricks have a certain amount of wear and tear and need to be leveled).

[0036] Step 8: Laying down new carbon bricks. Determine the elevation of the new carbon bricks, and then lay them layer by layer. Specifically: (1) Laying down new carbon bricks. Use the elevation of the upper surface of the same layer of retained carbon bricks to control the elevation of the new carbon bricks. Use thick carbon mortar for the mortar joints of carbon bricks within 2mm and ensure the fullness of the mortar in the joints. Fill the horizontal brick joints exceeding 2mm with refractory materials with similar performance to that part. Adjust the radius of the loose joints. (2) After laying down each layer of carbon bricks, check all the brick joints of the carbon bricks until they are adjusted to meet the requirements. Then construct the ramming material between the carbon bricks and the cooling wall. The construction of the ramming material must be carried out strictly in accordance with the construction requirements. After the work is completed, sampling and monitoring are carried out, and the next process is entered after passing the test; (3) In order to better monitor the furnace generation status in subsequent production, thermocouples are set at the junction of each layer of new and old carbon bricks; (4) During masonry, the horizontal joints and the release joints of the carbon bricks must be ensured, and the angles and brick joints at the junction of the new and old carbon bricks must be adjusted; (5) The second-to-last layer of carbon bricks is closed. Due to the insufficient space for the reserved carbon bricks on the upper part, the door cannot be closed according to the normal masonry method. In order to avoid the appearance of straight bricks for closing the door, it is calculated that when all the new carbon bricks are retreated to the cooling wall surface, the door bricks can be moved sideways. The maximum value of the entry is designed, and the door-closing bricks are designed to be wedge-shaped bricks according to the maximum value, and are pushed in horizontally from the side when closing the door; (6) Before the last layer of carbon bricks is laid, the carbon ramming material between the carbon bricks and the cooling wall needs to be prefabricated according to the size, and the last layer of carbon bricks is laid after the prefabricated blocks are completed; (7) When the last layer of carbon bricks is laid, the carbon bricks in the non-door-closing area are designed in two layers, and the second layer is designed to be small carbon blocks. The height of the small carbon blocks is larger than the design value. During laying, they are ground on site according to the actual situation so that the small carbon blocks can fit tightly with the upper retained carbon bricks; The last layer of carbon bricks closes the door The bricks are designed to be all small carbon bricks, which are laid layer by layer from the cooling wall direction into the furnace; (8) The last layer of carbon bricks is laid from both sides, and the carbon brick reinforcement supports are gradually removed on both sides until the entire construction is completed; (9) After all carbon bricks are laid, a 300mm thick castable is poured on the new carbon bricks and the junction of the new and old carbon bricks; (10) The castable at the junction of the new and old carbon bricks covers the old carbon bricks by at least 500mm, and the castable is transitioned at a 30° angle. This design helps to ensure that the flow direction of molten iron is in accordance with the construction requirements under production conditions in the furnace.

[0037] In summary, the beneficial technical effects of the present invention are: creatively removing part of the carbon bricks in the furnace and replacing them with new carbon bricks, providing a new idea for the maintenance of the blast furnace hearth. The repair construction technology is safe and reliable, so that the maintenance work can be carried out smoothly and the construction quality of the furnace hearth carbon bricks is ensured.

[0038] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0039] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A confined space blast furnace hearth maintenance construction method, characterized in that: include: Step 1: Detect the data of each point of the furnace, collect the temperature data of each point of the furnace to determine the scope of maintenance, removal and restoration; Step 2: Clean the slag, after the blast furnace is cooled and the temperature, gas and oxygen concentration are within a safe range, send the slag out of the furnace; Step 3: After the first section of the reinforcement device is added and the slag in the furnace is removed to a preset distance below the center line of the tuyere, the first section of the reinforcement device is sent into the furnace and installed in place at the corresponding position; Step 4: Remove the carbon bricks. After the first section of the reinforcement device is in place, first remove the carbon bricks above the iron mouth to the retained carbon bricks, then carry out the docking reinforcement of the second section of the reinforcement device, and finally remove the carbon bricks below the top surface of the residual iron; Step 5: Cutting of local residual iron: First, take protective measures on the carbon bricks on the bottom layer, and then cut the residual iron; Step 6: Remove the carbon bricks at the edge of the retained carbon bricks. After the residual iron cutting is completed, remove the carbon bricks that need to be removed that are adjacent to the retained carbon bricks; Step 7: After the residual iron cutting and carbon brick removal are completed, the residual on the surface of the cooling wall is polished and cleaned, and then the foundation is leveled with the furnace casting material; Step 8: Laying down new carbon bricks: Determine the elevation of new carbon bricks, and then lay them layer by layer.

2. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In the step 4, when the carbon bricks are removed, a displacement sensor is installed at the bottom of the remaining carbon bricks.

3. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In the step 4, when the overhanging size of the carbon bricks on both sides exceeds 2 / 3 of the width of the original carbon bricks, lateral supports are added for reinforcement.

4. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In the step 4, the removal of carbon bricks in the narrow area below the residual iron surface or in contact with the retained carbon bricks is carried out in coordination with the cutting of the residual iron.

5. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In the step 7, when the foundation is leveled, the upper surface of the castable should be kept level with the upper surface of the retained carbon brick in the radial direction.

6. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In step eight, when the penultimate layer of carbon bricks is laid, the maximum value of the door closing brick that can enter from the side when all the new carbon bricks are retreated to the cooling wall surface is calculated, and the door closing brick is designed as a wedge-shaped brick based on the maximum value, and is pushed in horizontally from the side when closing the door.

7. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In the step eight, the last layer of carbon bricks is laid, and the carbon bricks in the non-door closing area are designed in two layers, the second layer is designed to be small carbon blocks, and the height of the small carbon blocks is larger than the design value; the last layer of carbon brick door closing bricks is designed as all small carbon bricks, and are laid layer by layer from the cooling wall direction into the furnace.

8. The confined space blast furnace hearth maintenance construction method according to claim 1 is characterized in that: In the step five, the brittle layer between the carbon bricks and the scrap iron at the scrap iron cutting position is removed, the cutting drilling position is determined according to the maximum weight of the scrap iron lifting, and the scrap iron is cut through the brittle layer gap and the drill hole.

9. The confined space blast furnace hearth maintenance construction method according to claim 1, characterized in that: In the step eight, when laying new carbon bricks, a thermocouple is arranged at the junction of each layer of new and old carbon bricks.

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