A hot state step-by-step patching repair method for coke oven wall refractory bricks

Abstract

The application discloses a hot-state step-by-step patching repair method for coke oven wall refractory bricks and belongs to the technical field of coke oven maintenance. The hot-state step-by-step patching repair method for coke oven wall refractory bricks comprises the following steps: S1, construction detection and preparation; S2, old damaged wall body removal; S3, base layer interface pretreatment; S4, expansion joint positioning and setting, expansion joints filled with filling materials are set in layers and in directions in the bricklaying process; S5, new refractory brick bricklaying; S6, airtight heat preservation and maintenance; S7, gradient temperature rising treatment, the furnace temperature is raised to the normal working temperature in stages according to the preset temperature rising rate; and S8, sealing finishing and production resumption. In order to realize semi-hot-state local repair without stopping production, the application standardizes the whole-process process parameters, optimizes the joint structure and expansion joint design, reduces thermal shock, and improves the bonding strength of the new and old wall bodies, so that the service life of the repaired area is prolonged, the construction period is shortened, and the production and operation and maintenance costs are reduced.

Description

Technical Field

[0001] This invention belongs to the field of coke oven maintenance technology, and in particular relates to a hot-state stepped excavation and repair method for refractory bricks in coke oven walls. Background Technology

[0002] The walls of coke ovens are mainly constructed with silica bricks and operate in a high-temperature environment of 1200-1350℃ for a long time. They are also subjected to mechanical impacts from pushing coke and charging coal, chemical erosion from pulverized coal and raw coal gas, and thermal shock from alternating hot and cold temperatures. As a result, the walls are prone to defects such as local brick loss, erosion holes, deep and shallow cracks, and loose and peeling bricks.

[0003] Currently, coke oven wall repair is mainly divided into three categories: cold overall repair, hot spraying, and conventional local excavation and patching. 1. Cold repair requires the entire coke oven to be shut down and cooled down, resulting in a long downtime, significant loss of enterprise capacity, and extremely high energy consumption during the cooling and heating process; 2. Hot-applied refractory is an unshaped refractory material with weak bonding to the original silica brick matrix. It has poor wear resistance and thermal shock resistance, resulting in a short service life of the repair layer and repeated repairs that increase maintenance costs. 3. Traditional hot-state partial excavation and patching techniques have many defects: the construction temperature range is not properly controlled, and the temperature difference between the new bricks and the old wall is too large, resulting in thermal shock; the new and old walls are joined with straight joints, and the joint is prone to cracking and falling off during thermal expansion; the expansion joints are not set properly and the filling materials are not selected properly, causing secondary damage due to thermal expansion and contraction of the furnace body; there is no standardized process for cleaning the base layer, preheating the bricks, and heating and curing, resulting in unstable repair quality. Summary of the Invention

[0004] To address the above-mentioned technical deficiencies, this invention provides a hot-state stepped patching repair method for refractory bricks in coke oven walls, enabling partial repair without interrupting production in a semi-hot state. By standardizing the process parameters throughout the entire process, optimizing the joint structure and expansion joint design, thermal shock is reduced, and the bonding strength between the old and new walls is improved, thereby extending the service life of the repaired area, shortening the construction period, and reducing production and maintenance costs.

[0005] To achieve the above-mentioned technical objectives, the present invention is implemented through the following technical solution: A method for hot-state stepped patching repair of refractory bricks in coke oven walls, comprising: S1. Construction inspection and preparation, including delineating the damaged area, adjusting the furnace condition, and preparing materials and tools; S2. Demolition of old and damaged walls: remove the damaged bricks from top to bottom, and process the joint surface between the old and new walls into a stepped joint structure. S3. Base interface pretreatment: Apply thin fire mortar to the cleaned base surface to form a transition bonding layer. S4. Expansion joint positioning and setting: During the masonry process, expansion joints filled with filling material are set in layers and directions. S5. New refractory brick masonry: new bricks are laid in layers with staggered joints from bottom to top using standard fire mortar. S6. Sealed insulation and curing: After the masonry is completed, the furnace door is closed for constant temperature curing. S7. Gradient heating process: The furnace temperature is raised to the normal operating temperature in stages according to the preset heating rate. S8. Sealing and resuming production: After sealing the minor gaps, production is resumed.

[0006] Preferably, the step height of the stepped joint structure is the height of a single brick, and the step overlap width is not less than 1 / 3 of the brick length.

[0007] Preferably, the expansion joint includes a horizontal expansion joint and a vertical expansion joint. The horizontal expansion joint is set every 3 layers of refractory bricks, and the width of the horizontal expansion joint is 2 to 2.5 mm. The vertical expansion joint is set every 0.5 m along the height of the excavated area, and the width of the vertical expansion joint is 3 to 4 mm.

[0008] Preferably, the filling material for the expansion joint is asphalt-impregnated horse manure paper.

[0009] Preferably, in S5, when laying new refractory bricks, the vertical joints of two adjacent layers of refractory bricks are staggered, the stagger distance is not less than 1 / 4 of the brick length, and the mortar joint thickness is controlled between 1.2 and 1.8 mm.

[0010] Preferably, the constant temperature curing time is 24 hours, and the furnace temperature is maintained above 800°C during the curing period.

[0011] Preferably, the gradient heating process includes three stages: the first stage heats up to 1000℃ at a rate of 50℃ / day; the second stage heats up to 1200℃ at a rate of 70℃ / day; and the third stage heats up to the normal operating temperature of the coke oven at a rate of 80℃ / day.

[0012] Preferably, in S1, the materials include high-temperature silica bricks, silica mortar, expansion joint filler, and high-temperature resistant sealant.

[0013] Preferably, in S1, the siliceous fire clay is divided into dilute fire clay, standard fire clay, and concentrated fire clay.

[0014] Preferably, the water-cement mass ratio of the dilute fire clay is 0.85:1, the water-cement mass ratio of the standard fire clay is 0.7:1, and the water-cement mass ratio of the concentrated fire clay is 0.55:1.

[0015] The advantages and technical effects of this invention are: This invention allows for semi-hot construction with minimal capacity loss. It enables localized repairs without interrupting production in a semi-hot state, eliminating the need for a complete furnace shutdown for cooling and significantly reducing capacity loss and energy consumption associated with shutdowns.

[0016] The present invention has a reasonable structure and strong crack resistance. It uses stepped joints to replace traditional straight joints and is combined with a standardized expansion joint system to effectively offset the high-temperature thermal expansion stress of silica bricks, eliminate joint cracking and brick detachment problems, and significantly improve the service life of the repaired area compared with traditional processes.

[0017] The entire process parameters are controllable, ensuring stable repair quality. Key process parameters such as brick preheating, mortar ratio, joint thickness, and heating rate are quantitatively specified, and standardized operations avoid human error, resulting in high repair consistency.

[0018] The present invention has low thermal shock and can effectively protect the original furnace body. The preheating silica bricks and gradient heating system greatly reduce the thermal shock of temperature difference between the old and new bricks and the furnace body, and avoid secondary cracks in the surrounding intact furnace walls.

[0019] The present invention has high construction efficiency, clear process division, and matching special tools, shortens the construction cycle of single local excavation and patching, and significantly reduces labor and maintenance costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of a preferred embodiment of the present invention is shown. Detailed Implementation

[0022] To make the above-mentioned objectives, control system design, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] This invention relates to the repair of damaged coke oven walls, employing a hot-dip patching method. First, the cavity is cooled, safety precautions are taken, materials are prepared, and the damaged area is surveyed. Damaged bricks are removed from top to bottom, and the base surface is cleaned, leaving expansion joints. Silicon bricks of the same specification are used for staggered laying, controlling the mortar joint thickness and smoothing the joints. Subsequently, insulation material is applied for curing, followed by a gradual, gradual increase in temperature. Production resumes after acceptance testing. Continuous inspections are conducted after completion, with strict temperature and safety control throughout the process to ensure repair quality.

[0024] Please see Figure 1A method for hot-state stepped patching repair of refractory bricks in coke oven walls, comprising: S1. Construction inspection and site preparation; specifically including: Defect detection and area delineation are carried out using an industrial endoscope inside the furnace, an infrared thermometer, and a feeler gauge to detect damaged areas: identifying molten holes, spalling, cracks, and loose areas, and measuring the depth of damage, crack width, and damaged area; the construction area is delineated by extending the excavation and repair boundary outward by 60-80mm, and a rectangular construction outline is marked on the surface of the damaged furnace wall; if there is a through crack, the entire length of the crack is included in the excavation and repair area.

[0025] Adjust the furnace operating conditions to completely push out the coke inside the carbonization chamber to be repaired, keeping the furnace empty; close the heating gas valve, and allow the inner wall of the furnace to cool down naturally.

[0026] Material preparation and pretreatment: Main brick material: High-temperature silica bricks are selected, with no cracks or missing corners in appearance, and dimensional deviation ≤ ±1mm; Bonding material: Siliceous fire mortar, particle size ≤0.45mm, divided into three categories: base thin fire mortar, standard masonry fire mortar, and sealing thick fire mortar; Thin refractory mortar: water-cement ratio 0.85:1; Standard refractory mortar: water-cement ratio 0.7:1; Thick refractory mortar: water-cement ratio 0.55:1; Expansion joint filling material: 3-4mm thick asphalt-impregnated cardboard; Auxiliary materials: high-temperature resistant sealant, high-temperature resistant protective cotton, and temporary support steel.

[0027] Tools and safety precautions are provided, including a hollow brick-picking hammer, a high-pressure air gun (working air pressure 0.55MPa), a special shovel, a masonry trowel, a grouting knife, a spirit level, and a thermometer; temporary H-beam supports are erected outside the construction area to prevent the surrounding intact bricks from loosening and collapsing.

[0028] S2. Demolition of old, damaged walls (layered work from top to bottom); specifically includes: Strictly follow the marked outline during operation, and use a hollow brick-removing hammer to remove broken bricks, loose bricks, slag and surface graphite layer by layer from top to bottom. Do not strike with a large hammer to avoid vibration damage to the surrounding intact furnace walls.

[0029] During the demolition process, the joint between the old and new walls will be processed into a stepped joint structure. The height of the step will be the height of a single brick, and the overlap width of the step will be ≥1 / 3 of the brick length. Vertical straight joints will be strictly prohibited throughout the process.

[0030] Remove the brickwork until it reaches a hard, dense, and intact brick base. Control the depth of excavation and repair according to the thickness of the original wall. The height of a single layer of bricks to be removed should not exceed 5 layers.

[0031] After demolition, use 0.55MPa compressed air to thoroughly blow away the base surface, brick joints, and step joint gaps to completely remove loose brick debris, dust, and graphite. After blowing, let it stand for 15 minutes to ensure that the base is dry and free of debris.

[0032] S3, Basic Interface Preprocessing; specifically including: After cleaning, apply a thin layer of silica refractory putty evenly to the entire construction base and stepped joint surface, with a thickness of 1.5-2 mm, ensuring complete coverage without any omissions. Allow it to air dry for 30 minutes to form a transition bonding layer, enhancing the bonding strength between the new and old refractory materials.

[0033] S4. Expansion joint positioning and setup; specifically including: Taking into account the high-temperature thermal expansion characteristics of coke ovens, expansion joints are set in layers and directions, and all expansion joints are filled with asphalt-impregnated cardboard. Horizontal expansion joints: A horizontal expansion joint is set every 3 layers of silica bricks, with a joint width of 2 to 2.5 mm, and is arranged along the entire length of the excavated and patched area; Vertical expansion joints: A vertical expansion joint is set every 0.5m in the height of the excavated area, with a joint width of 3-4mm, and the vertical joint is continuous with the horizontal joint. Expansion joints should be placed away from the center of the brickwork, at the joint between the bricks, and the filling material should be used to fill the gaps and compact them, ensuring that there are no gaps or loose parts.

[0034] S5. New refractory brick masonry (layered masonry from bottom to top), specifically including: Construction sequence: Follow the principle of bottom-up and staggered joints. The vertical joints of two adjacent layers of silica bricks should be staggered, with a stagger distance of ≥1 / 4 brick length. Vertical joints that run through the bricks are strictly prohibited.

[0035] Mortar joint control: Standard silica mortar is used for masonry. The horizontal and vertical mortar joints are uniformly controlled to be 1.2-1.8mm, and the mortar joint fullness is ≥95%.

[0036] Brick placement: Silicon bricks should be gently tapped into place, and strong impacts are strictly prohibited; at the joint between new and old walls, the top surface of the new brick should be 2mm lower than the top surface of the adjacent old brick to allow for thermal expansion.

[0037] After each layer of masonry is completed, immediately use a grouting knife to clean up any excess mortar and smooth the surface initially. After each layer is completed, check the flatness; if the deviation is ≤2mm, the next layer can be constructed.

[0038] After the entire wall is built to the original design elevation, the top joints are repaired to ensure that the overall wall surface is flat and continuous.

[0039] S6. Sealed thermal insulation curing, specifically including: After all the masonry work is completed, immediately close the furnace door to achieve airtight insulation; Natural constant temperature curing for 24 hours, during which the temperature inside the furnace is maintained above 800℃. Ventilation, cooling, and disturbance of the walls are prohibited to ensure that the fire clay fully solidifies and bonds.

[0040] S7, Gradient heating process, specifically includes: After curing, gradually increase the furnace temperature according to a gradient heating system to avoid thermal shock cracking caused by rapid heating. Phase 1: Heating rate of 50℃ / day, raising the furnace temperature to 1000℃; Second stage: Heating rate of 70℃ / day, raising the furnace temperature to 1200℃; The third stage: the heating rate is 80℃ / day, gradually increasing to the normal operating temperature of the coke oven, 1200℃~1300℃; The furnace wall temperature and expansion joint status are monitored in real time throughout the heating process. If abnormal expansion of the gaps or loosening of the bricks occurs, the heating rate is immediately slowed down and the problem is investigated and dealt with.

[0041] S8. Sealing and resuming production, specifically including: After the furnace temperature reaches the normal operating temperature and stabilizes for 8 hours, sealing work is carried out: for micro cracks and joint gaps of less than 2mm, a mixture of concentrated silica fire clay and high-temperature resistant sealant is used for grouting, compaction, and smoothing. Remove temporary supports, construction tools, and protective facilities; clean up debris inside the furnace. Gradually resume coal charging, coking, and coking processes. First, extend the coking time for two trial runs. If no abnormalities are found, resume normal coking oven production.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for hot-state stepped patching and repair of refractory bricks in coke oven walls, characterized in that, include: S1. Construction inspection and preparation, including delineating the damaged area, adjusting the furnace condition, and preparing materials and tools; S2. Demolition of old and damaged walls: remove the damaged bricks from top to bottom, and process the joint surface between the old and new walls into a stepped joint structure. S3. Base interface pretreatment: Apply thin fire mortar to the cleaned base surface to form a transition bonding layer. S4. Expansion joint positioning and setting: During the masonry process, expansion joints filled with filling material are set in layers and directions. S5. New refractory brick masonry: new bricks are laid in layers with staggered joints from bottom to top using standard fire mortar. S6. Sealed insulation and curing: After the masonry is completed, the furnace door is closed for constant temperature curing. S7. Gradient heating process: The furnace temperature is raised to the normal operating temperature in stages according to the preset heating rate. S8. Sealing and resuming production: After sealing the minor gaps, production is resumed.

2. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 1, characterized in that, The step height of the stepped joint structure is the height of a single brick, and the step overlap width is not less than 1 / 3 of the brick length.

3. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 1, characterized in that, The expansion joints include horizontal expansion joints and vertical expansion joints. The horizontal expansion joints are set every 3 layers of refractory bricks, and the width of the horizontal expansion joints is 2 to 2.5 mm. The vertical expansion joints are set every 0.5 m along the height of the excavated area, and the width of the vertical expansion joints is 3 to 4 mm.

4. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 3, characterized in that, The expansion joint is filled with asphalt-impregnated horse manure paper.

5. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 1, characterized in that, In S5, when laying new refractory bricks, the vertical joints of two adjacent layers of refractory bricks are staggered, with a stagger distance of not less than 1 / 4 of the brick length, and the mortar joint thickness is controlled between 1.2 and 1.8 mm.

6. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 1, characterized in that, The constant temperature curing time is 24 hours, and the temperature inside the furnace is maintained above 800℃ during the curing period.

7. The hot-state stepped patching repair method for refractory bricks in coke oven walls according to claim 1, characterized in that, The gradient heating process includes three stages: the first stage heats up to 1000℃ at a rate of 50℃ / day; the second stage heats up to 1200℃ at a rate of 70℃ / day; and the third stage heats up to the normal operating temperature of the coke oven at a rate of 80℃ / day.

8. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 1, characterized in that: In S1, the materials include high-temperature silica bricks, silica caustic soda, expansion joint filling material, and high-temperature resistant sealant.

9. The hot-state stepped patching repair method for refractory bricks in coke oven walls according to claim 1, characterized in that, In S1, the siliceous fire clay is divided into dilute fire clay, standard fire clay, and concentrated fire clay.

10. The hot-state stepped patching and repair method for refractory bricks in coke oven walls according to claim 9, characterized in that: The water-cement ratio of thin refractory is 0.85:1, the water-cement ratio of standard refractory is 0.7:1, and the water-cement ratio of thick refractory is 0.55:1.

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