Method for treating local thickening at lower part of blast furnace shaft

Abstract

The invention relates to the technical field of blast furnace ironmaking, in particular to a method for treating local thickness at the lower part of a blast furnace shaft, which comprises the following steps: adding additional coke at a furnace throat above the local thickness part at the lower part of the blast furnace shaft, and closing a tuyere coal injection gun below the local thickness part at the lower part of the blast furnace shaft when the additional coke reaches a soft melting zone; developing local edge airflow to perform thermal shock and scouring on the local thickness at the lower part of the blast furnace body, so as to promote the local thickness at the lower part of the blast furnace body to fall off. According to the method, the local thickness at the lower part of the blast furnace body is scoured and thermally shocked by adopting a mode of combining additional coke, closing the tuyere coal injection gun below the local thickness at the lower part of the blast furnace body and developing local edge airflow, the specific operation is simple and convenient, the side effect on the blast furnace is small, the smooth running state of the blast furnace is basically not influenced, and the service life of the blast furnace is prolonged. The damage to the furnace condition of the blast furnace and cooling equipment due to treatment of local thickening at the lower part of the blast furnace body is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace ironmaking, and in particular to a method for treating local thickening at the lower part of a blast furnace shaft. Background Art

[0002] The local thickening of the lower part of the blast furnace shaft refers to the adhesive material in the lower part of the blast furnace shaft that exceeds the normal thickness due to the reduction of raw material quality, cyclic enrichment of harmful elements or alkali metals, water leakage of cooling wall, improper control of cooling intensity, and long-term overweight of the edge during the operation of the blast furnace during normal operation. The local thickening of the lower part of the blast furnace shaft is generally manifested as a local bulge or a large area bulge from the inside of the shaft toward the center. Due to the low thermal conductivity of the thickened material, the local thickening of the lower part of the blast furnace shaft will cause a decrease in the local heat flux intensity, which is intuitively manifested as the cooling wall temperature at the thickened part is lower than that at the normal position, and the cooling wall water temperature difference at this part is reduced. After the thickening falls off, the cooling wall temperature will return to normal levels.

[0003] The bulges caused by the local thickening in the lower part of the blast furnace body will affect the normal descent of the charge at the raised position, resulting in the deviation of the charge in the blast furnace. The bulge also makes the originally regular circle inside the furnace body irregular, thereby changing the edge airflow distribution. The deviation of the charge in the blast furnace and the change of the airflow distribution will destroy the long-term stable and smooth operation of the blast furnace, and have a great adverse impact on the economic and technical indicators of the blast furnace. The local thickening in the lower part of the blast furnace body will also cause frequent fluctuations in the static pressure of the furnace body in this direction, thereby generating pipeline airflow. Severe pipeline airflow will cause the blast furnace top pressure to fluctuate violently, the furnace top temperature to rise rapidly, and affect the safe operation of the gas pipeline and dust removal system.

[0004] In the traditional blast furnace production process, no treatment measures are generally taken for slight local thickening of the lower part of the blast furnace shaft. For serious local thickening of the lower part of the blast furnace shaft, the material surface is lowered to expose the thickened part, and then it is cleaned manually or mechanically. After the cleaning is completed, the material is reloaded and the furnace is opened. If the thickening is not serious and only affects the economic indicators of the blast furnace and has not yet destroyed the smooth operation of the furnace, the blast furnace workers generally use one or a combination of the following treatment measures: (1) Develop the overall peripheral edge airflow of the blast furnace. By adjusting the blast furnace charging system, reducing the coke load at the edge of the blast furnace, and developing the overall peripheral edge airflow of the blast furnace. The more developed edge airflow scours the thickened parts, thereby reducing or shedding the thickness. This method is likely to cause the protective slag skin of the non-thickened parts of the blast furnace body to fall off, which in turn leads to scouring and wear of the cooling wall and severe thermal shock, accelerating the damage of the cooling wall. At the same time, a large amount of slag skin shedding will also cause the blast furnace thermal system to malfunction. If the coke load or operation is not handled properly or in a timely manner, it is very easy to cause the rapid loss of heat reserve in the blast furnace hearth, resulting in unqualified pig iron, or even freezing of the hearth.

[0005] (2) Reduce the local cooling intensity, causing the local thickening of the lower part of the blast furnace body to fall off. By adjusting the cooling wall water flow rate at the thickening part, the local cooling intensity of the blast furnace is reduced, causing the adhesive at this location to melt and fall off. This method can easily cause the local cooling wall to expand and deform due to a large temperature rise, causing the cooling water pipe of the cooling wall to be subjected to shear stress and cause the root to rupture and leak. After the water pipe leaks, the cooling wall cannot be cooled normally, which will cause the cooling wall to burn, and then the temperature of the local furnace shell will rise, posing a huge safety risk of furnace body burning through. This kind of damage cannot be repaired during normal maintenance and can only be replaced during maintenance at the lowering surface, which poses a great safety hazard.

[0006] (3) Reduce the coke load, increase the furnace temperature, and hot wash the furnace wall. This measure alone cannot eliminate the local thickening of the lower part of the blast furnace body. Under normal circumstances, it is used in conjunction with other measures to avoid a sharp drop in furnace temperature due to the shedding of slag skin from the furnace body, which may lead to quality accidents.

[0007] (4) Reduce the basicity of slag, reduce the melting temperature of slag, and promote the melting and shedding of slag. Blast furnace slag is a glassy material without a fixed melting point. The melting temperature of slag increases with the increase of basicity. By reducing the basicity, the melting temperature of slag is reduced, the fluidity of slag is improved, and the local thickening of the lower part of the blast furnace body is cleaned to reduce or shedding the thickening. In order to reduce the melting temperature of slag, the basicity of blast furnace batching can only be reduced. The reduction of slag basicity will reduce the desulfurization capacity of slag, which will lead to an increase in the sulfur content in pig iron, reduce the quality of pig iron, and even cause quality accidents.

[0008] (5) Add flux to clean the blast furnace wall. Fluxes such as fluorite and silica are added to the charge to improve the fluidity of the slag, strengthen the cleaning of the local thickening in the lower part of the blast furnace body, and promote the reduction or shedding of the thickening. Fluxes are acidic substances, which will greatly reduce the desulfurization capacity of the slag, resulting in a significant increase in the sulfur content in the pig iron. If not properly controlled, quality accidents are very likely to occur. Moreover, fluxes will cause the protective slag skin in non-thickening parts to melt and fall off, which will then cause a significant increase in the heat load in non-thickening parts, leading to erosion and wear of the cooling wall and severe thermal shock, accelerating the damage of the cooling wall.

[0009] Traditional treatment measures for local thickening in the lower part of the blast furnace shaft have shortcomings. The method of lowering the material surface to treat the thickening is very effective, but the treatment cost is too high. Other treatment measures have average treatment effects and have significant side effects. Summary of the invention

[0010] In view of the technical problems that the methods for treating the local thickening of the lower part of the blast furnace shaft in the prior art have high risks and poor effects, the present invention provides a method for treating the local thickening of the lower part of the blast furnace shaft, which takes into account the smooth operation of the blast furnace condition and the safety of cooling equipment, and avoids the damage to the blast furnace condition and cooling equipment caused by treating the local thickening of the lower part of the blast furnace shaft.

[0011] The technical solution of the present invention is as follows: A method for treating local thickening of the lower part of a blast furnace shaft comprises adding additional coke at the furnace throat above the local thickening part of the lower part of the blast furnace shaft, and when the additional coke reaches the soft melting zone, closing the tuyere coal injection gun below the local thickening of the lower part of the blast furnace shaft, developing local edge airflow to thermally shock and scour the local thickening of the lower part of the blast furnace shaft, thereby causing the local thickening of the lower part of the blast furnace shaft to fall off.

[0012] Furthermore, before adding the additional coke, the location of the local thickening in the lower part of the blast furnace shaft is determined, and the severity of the local thickening in the lower part of the blast furnace shaft is judged.

[0013] Furthermore, the location of the local thickening in the lower part of the blast furnace shaft is determined based on the difference in temperature distribution of the cooling wall; the condition of the blast furnace charge surface is judged based on the performance of the camera and the probe in the blast furnace, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged.

[0014] Furthermore, when the water temperature of at least one cooling wall in the same section is 3-15°C lower than the water temperature of other cooling walls in the same section, it is judged that there is local thickness in the lower part of the blast furnace shaft on the cooling wall; when the camera inside the blast furnace detects that there is a depth difference of 0.3-1.2m between two of the probes among the east probe, west probe and south probe, it is necessary to process the local thickness in the lower part of the blast furnace shaft.

[0015] Furthermore, the additional coke fed into the furnace adopts a fixed-point distribution mode or a fan-shaped distribution mode. When the local thickening area of ​​the lower part of the blast furnace body is n cooling wall areas, the distribution amount of the additional coke is n tons, n>0.

[0016] Furthermore, every time the thickness area reaches 3 cooling walls, one tuyere coal injection gun below the local thickness of the lower part of the blast furnace body is closed. When the number of closed coal injection guns is more than two, the tuyere coal injection guns are closed at intervals.

[0017] Furthermore, additional coke is added at the throat above the local thickening part of the lower part of the blast furnace shaft. When the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening part of the lower part of the blast furnace shaft is closed, and the local edge airflow is developed to perform thermal shock and flushing on the local thickening part of the lower part of the blast furnace shaft. The process is repeated at least once until the local thickening part of the lower part of the blast furnace shaft falls off and melts.

[0018] Further, the following steps are included: (1) Determine the location of local thickening in the lower part of the blast furnace shaft based on the difference in temperature distribution of the cooling wall; (2) According to the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface is judged, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged; (3) Adding additional coke to the corresponding throat position just above the local thickening position of the lower part of the blast furnace shaft, and using the local excess additional coke to heat the local thickening position of the lower part of the blast furnace shaft to compensate for the heat loss after the local thickening of the lower part of the blast furnace shaft falls off and melts; (4) When the additional coke reaches the soft melting zone, the tuyere coal injection guns below the local thickening of the lower part of the blast furnace shaft are closed; according to the location and severity of the local thickening of the lower part of the blast furnace shaft, the corresponding direction and number of tuyere coal injection guns to be closed are determined; when the additional coke reaches the soft melting zone, the tuyere coal injection guns below the local thickening of the lower part of the blast furnace shaft are closed; (5) Repeating steps (3) and (4) in sequence causes the local thickness of the lower part of the blast furnace shaft to be subjected to continuous scouring and thermal shock until the thickness of the shaft falls off and melts.

[0019] The beneficial effects of the present invention are: (1) Accurately eliminate thickening: By adding additional coke at the furnace throat and closing the tuyere coal injection gun below the thickening part, the local thickening at the bottom of the blast furnace shaft can be accurately thermally shocked and flushed, causing the thickening to fall off quickly. Compared with the traditional method, the present invention does not require lowering the material level or manual cleaning, significantly reducing the processing cost and time.

[0020] (2) Maintain stable furnace conditions: Additional coke releases a large amount of heat when burning in the soft melting zone, which compensates for the heat loss when the thickening occurs, avoids drastic fluctuations in furnace temperature, maintains sufficient heat reserves in the furnace, and ensures a stable thermal system of the blast furnace. By developing local edge airflow, the thickening areas can be accurately flushed to avoid unnecessary damage to the cooling wall and slag skin in the non-thickening areas.

[0021] (3) Reduce side effects: Traditional methods (such as reducing cooling intensity or adjusting edge airflow) can easily lead to damage to the cooling wall, abnormal furnace temperature or reduced pig iron quality. This solution minimizes these side effects by controlling the operation of additional coke and coal injection guns. The local edge airflow developed after shutting down the coal injection gun can avoid drastic fluctuations in furnace conditions and ensure smooth operation of the blast furnace.

[0022] (4) Simple operation and strong applicability: This solution is simple and easy to operate by adding additional coke and closing the coal injection gun, without the need for complex equipment or major adjustments to the production rhythm. It is suitable for blast furnaces of different volumes and can flexibly adjust the amount of additional coke and the number of coal injection guns closed according to the location and severity of the thickening, and has wide applicability.

[0023] (5) Improve the quality of pig iron: By precisely controlling the operation of the additional coke and coal injection gun, the large fluctuation of slag basicity and the increase of sulfur content in pig iron are avoided, ensuring the stability of pig iron quality. Compared with the traditional method, this solution will not cause the quality of pig iron to decrease due to the decrease of slag basicity or the addition of flux.

[0024] (6) Extending equipment life: By controlling local airflow and heat distribution, excessive scouring and thermal shock of the cooling wall are avoided, the wear and damage of the cooling wall are reduced, and the service life of the equipment is extended. Compared with traditional methods, this solution significantly reduces the risk of cooling wall rupture and furnace shell burn-through.

[0025] (7) Energy saving and consumption reduction: By controlling the amount of additional coke and the operation of the coal injection gun, unnecessary heat waste is avoided and fuel consumption is reduced. Compared with the traditional material surface cleaning method, this solution does not require stopping the furnace or significantly adjusting the production rhythm, reducing energy waste and production losses. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] Example 1 A method for treating local thickening at the lower part of a blast furnace shaft comprises the following steps: (1) Determine the local thickening position of the lower part of the blast furnace shaft according to the difference in the temperature distribution of the cooling wall: The local thickening of the lower part of the blast furnace shaft will lead to the obstruction of heat transfer in the blast furnace, which is intuitively manifested as the furnace body temperature and the cooling wall water temperature of the local thickening position of the lower part of the blast furnace shaft are lower than those of the normal position. According to the difference between the furnace body temperature and the cooling wall water temperature, determine the local thickening position of the lower part of the blast furnace shaft; The temperature of the 18#-22# cooling walls in the 11th and 12th sections of the 5100m³ blast furnace body (the body has 10-18 sections from bottom to top) (the 5100m³ blast furnace has a total of 40 tuyere openings, and the positions of the tuyere openings are horizontally parallel to the 6th section, among which the 1# tuyere opening is in the north direction and arranged clockwise; the 1# cooling walls in the 11th and 12th sections are in the same direction as the 1# tuyere, and the other cooling walls in the same section are arranged clockwise) is 5-15℃ lower than that of other cooling walls in the same section. It is judged that there is a local thickening of the lower part of the blast furnace body in this area, resulting in a decrease in thermal conductivity, which directly manifests as a lower than normal furnace body temperature; (2) According to the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface is judged, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged; The video and probe inside the 5100m³ blast furnace show that the east probe is shallow and the west probe is deep, with a depth difference of 0.9m. The overall furnace condition is in good condition. The local thickening of the lower part of the blast furnace shaft affects the distribution of local edge airflow. The local thickening of the lower part of the blast furnace shaft on the east side causes the material feeding to be slower than other directions, resulting in uneven material lines. Combined with the degree of furnace condition, it is judged that the thickening situation is not serious, and there is no need to expose the thickened parts for manual or mechanical cleaning; (3) Add additional coke to the corresponding throat position just above the local thickening position of the lower part of the blast furnace shaft, and use the local excess additional coke to heat the local thickening position of the lower part of the blast furnace shaft to make up for the heat loss after the local thickening of the lower part of the blast furnace shaft falls off and melts, maintain sufficient heat reserve in the furnace, and avoid abnormal thermal system of the blast furnace. Add additional coke to the furnace at a fixed point from the β angle of the distribution chute to ensure that the coke entering the furnace is the local thickening position of the lower part of the blast furnace shaft. According to the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is selected. For every 1 cooling wall area of ​​the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is 1 ton, and so on. In the direction of 18#-22# cooling wall, the temperature of 5 cooling wall areas was abnormal, and 5 tons of additional coke was added in fan-shaped distribution mode; (4) When the additional coke reaches the soft melting zone, the tuyere coal injection gun is closed; the corresponding direction and number of tuyere coal injection guns to be closed are determined according to the location and severity of the local thickening of the lower part of the blast furnace shaft; when the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening of the lower part of the blast furnace shaft is closed; for every three cooling walls of the thickening area, one coal injection gun in the corresponding direction of the local thickening of the lower part of the blast furnace shaft is closed. If the number of closed coal injection guns is more than two, they need to be closed at intervals to avoid causing furnace condition fluctuations; by closing the tuyere coal injection guns at the corresponding parts, the local material feeding speed can be increased, the local edge airflow can be developed, the local high temperature area can be raised, and the thickening parts can be heated. The scouring and temperature rise of the local edge airflow scour and thermally shock the local thickening of the furnace shaft, causing the local thickening of the lower part of the blast furnace shaft to fall off; After 25 batches of materials (materials include ore and coke for smelting, and the mass of one batch of materials in a 5100m³ blast furnace is about 170 tons), 5 tons of additional coke arrive at the soft melting zone, the 14# tuyere coal injection gun (corresponding to cooling wall 20#) is closed, and local edge airflow is developed to scour and thermally shock the thickening, causing the local thickening at the lower part of the blast furnace shaft to fall off; (5) Repeating steps (3) and (4) in sequence to subject the local furnace body thickness to continuous scouring and thermal shock until the furnace body thickness falls off and melts; One hour after closing the No. 14 tuyere coal injection gun, the static pressure of the east-facing 11th section furnace body fluctuated violently. The material surface was 2.3m deep after the east-facing material collapsed. At the same time, the static pressure dropped. When the static pressure fluctuated, the furnace body temperature rose rapidly, and then gradually dropped. The fault was caused by the partial thickening and falling off of the furnace body. The blast furnace did not take other countermeasures and the transition was smooth.

[0028] Example 2 A method for treating local thickening at the lower part of a blast furnace shaft comprises the following steps: (1) Determine the local thickening position of the lower part of the blast furnace shaft according to the difference in the temperature distribution of the cooling wall: The local thickening of the lower part of the blast furnace shaft will lead to the obstruction of heat transfer in the blast furnace, which is intuitively manifested as the furnace body temperature and the cooling wall water temperature of the local thickening position of the lower part of the blast furnace shaft are lower than those of the normal position. According to the difference between the furnace body temperature and the cooling wall water temperature, determine the local thickening position of the lower part of the blast furnace shaft; The temperature of the 5#-7# cooling walls in the 7th and 8th sections of the 1750m³ blast furnace body (the body is divided into 7th to 14th sections from bottom to top) (the 1750m³ blast furnace has a total of 24 tuyere, and the positions of the tuyere are horizontally parallel to the 4th section. Among them, the 1# tuyere is in the north direction and arranged clockwise; the 1# cooling walls in the 7th and 8th sections are in the same direction as the 1# tuyere, and the other cooling walls in the same section are arranged clockwise) is 3-10℃ lower than that of other cooling walls in the same section. It is judged that there is a local thickening in the lower part of the blast furnace body at this location, resulting in a decrease in thermal conductivity, which directly manifests as a lower furnace body temperature than normal; (2) According to the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface is judged, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged; The video and probe inside the 1750m³ blast furnace show that the probe is shallow in the east and deep in the west, with a depth difference of 0.6m. The overall furnace condition is in good condition. The local thickening of the lower part of the blast furnace shaft affects the distribution of local edge airflow. The local thickening of the lower part of the blast furnace shaft on the east side causes the material feeding to be slower than other directions, resulting in uneven material line. Combined with the degree of furnace condition, it is judged that the thickening situation is not serious, and there is no need to expose the thickened parts for manual or mechanical cleaning; (3) Add additional coke to the corresponding throat position just above the local thickening position of the lower part of the blast furnace shaft, and use the local excess additional coke to heat the local thickening position of the lower part of the blast furnace shaft to make up for the heat loss after the local thickening of the lower part of the blast furnace shaft falls off and melts, maintain sufficient heat reserve in the furnace, and avoid abnormal thermal system of the blast furnace. Add additional coke to the furnace at a fixed point from the β angle of the distribution chute to ensure that the coke entering the furnace is the local thickening position of the lower part of the blast furnace shaft. According to the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is selected. For every 1 cooling wall area of ​​the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is 1 ton, and so on. In the direction of 5#-7# cooling wall, the temperature of 3 cooling wall areas was abnormal, and 3 tons of additional coke was added in fixed-point distribution mode; (4) When the additional coke reaches the soft melting zone, the tuyere coal injection gun is closed; the corresponding direction and number of tuyere coal injection guns to be closed are determined according to the location and severity of the local thickening of the lower part of the blast furnace shaft; when the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening of the lower part of the blast furnace shaft is closed; for every three cooling walls of the thickening area, one coal injection gun in the corresponding direction of the local thickening of the lower part of the blast furnace shaft is closed. If the number of closed coal injection guns is more than two, they need to be closed at intervals to avoid causing furnace condition fluctuations; by closing the tuyere coal injection guns at the corresponding parts, the local material feeding speed can be increased, the local edge airflow can be developed, the local high temperature area can be raised, and the thickening parts can be heated. The scouring and temperature rise of the local edge airflow scour and thermally shock the local thickening of the furnace shaft, causing the local thickening of the lower part of the blast furnace shaft to fall off; After 20 batches of materials (materials include ore and coke for smelting, and the mass of one batch of materials in a 1750m³ blast furnace is about 60 tons), 3 tons of additional coke arrive at the soft melting zone, the 3# tuyere coal injection gun (corresponding to cooling wall 6#) is closed, and local edge airflow is developed to scour and thermally shock the thickening, causing the local thickening at the lower part of the blast furnace shaft to fall off; (5) Repeating steps (3) and (4) in sequence to subject the local furnace body thickness to continuous scouring and thermal shock until the furnace body thickness falls off and melts; 30 minutes after closing the 3# tuyere coal injection gun, the static pressure of the east-facing 7th section furnace body fluctuated violently. The material surface was 2.5m deep after the east-facing material collapsed. At the same time, the static pressure dropped. When the static pressure fluctuated, the furnace body temperature rose rapidly, and then gradually dropped. The fault was caused by the partial furnace body thickening and falling off. The blast furnace did not take other countermeasures and the transition was smooth.

[0029] Example 3 A method for treating local thickening at the lower part of a blast furnace shaft comprises the following steps: (1) Determine the local thickening position of the lower part of the blast furnace shaft according to the difference in the temperature distribution of the cooling wall: The local thickening of the lower part of the blast furnace shaft will lead to the obstruction of heat transfer in the blast furnace, which is intuitively manifested as the furnace body temperature and the cooling wall water temperature of the local thickening position of the lower part of the blast furnace shaft are lower than those of the normal position. According to the difference between the furnace body temperature and the cooling wall water temperature, determine the local thickening position of the lower part of the blast furnace shaft; The temperature of the 45# and 46# cooling walls in the 10th and 11th sections of the 5100m³ blast furnace body (the body has 10-18 sections from bottom to top) (the 5100m³ blast furnace has a total of 40 tuyere openings, and the positions of the tuyere openings are horizontally parallel to the 6th section, among which the 1# tuyere opening is in the north direction and arranged clockwise; the 1# cooling walls in the 10th and 11th sections are in the same direction as the 1# tuyere, and the other cooling walls in the same section are arranged clockwise) is 5-15℃ lower than that of other cooling walls in the same section. It is judged that there is a local thickening of the lower part of the blast furnace body in this part, resulting in a decrease in thermal conductivity, which directly manifests as a lower furnace body temperature than normal; (2) According to the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface is judged, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged; The video and probe inside the 5100m³ blast furnace show that the probe is deep in the east and shallow in the west, with a depth difference of 0.8m. The overall furnace condition is in good condition. The local thickening of the lower part of the blast furnace shaft affects the distribution of local edge airflow. The local thickening of the lower part of the blast furnace shaft on the east side causes the material feeding to be slower than other directions, resulting in uneven material lines. Combined with the degree of furnace condition, it is judged that the thickening situation is not serious, and there is no need to expose the thickened parts for manual or mechanical cleaning; (3) Add additional coke to the corresponding throat position just above the local thickening position of the lower part of the blast furnace shaft, and use the local excess additional coke to heat the local thickening position of the lower part of the blast furnace shaft to make up for the heat loss after the local thickening of the lower part of the blast furnace shaft falls off and melts, maintain sufficient heat reserve in the furnace, and avoid abnormal thermal system of the blast furnace. Add additional coke to the furnace at a fixed point from the β angle of the distribution chute to ensure that the coke entering the furnace is the local thickening position of the lower part of the blast furnace shaft. According to the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is selected. For every 1 cooling wall area of ​​the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is 1 ton, and so on. In the direction of the 45# and 46# cooling walls, the temperature of a total of 4 cooling wall areas was abnormal, and 4 tons of additional coke was added in a fan-shaped distribution mode; (4) When the additional coke reaches the soft melting zone, the tuyere coal injection gun is closed; the corresponding direction and number of tuyere coal injection guns to be closed are determined according to the location and severity of the local thickening of the lower part of the blast furnace shaft; when the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening of the lower part of the blast furnace shaft is closed; for every three cooling walls of the thickening area, one coal injection gun in the corresponding direction of the local thickening of the lower part of the blast furnace shaft is closed. If the number of closed coal injection guns is more than two, they need to be closed at intervals to avoid causing furnace condition fluctuations; by closing the tuyere coal injection guns at the corresponding parts, the local material feeding speed can be increased, the local edge airflow can be developed, the local high temperature area can be raised, and the thickening parts can be heated. The scouring and temperature rise of the local edge airflow scour and thermally shock the local thickening of the furnace shaft, causing the local thickening of the lower part of the blast furnace shaft to fall off; After 25 batches of materials (materials include ore and coke for smelting, and the mass of one batch of materials in a 5100m³ blast furnace is about 170 tons), 4 tons of additional coke arrive at the soft melting zone, the 30# tuyere coal injection gun (corresponding to 45# cooling wall) is closed, and local edge airflow is developed to scour and thermally shock the thickening, causing the local thickening at the lower part of the blast furnace shaft to fall off; (5) Repeating steps (3) and (4) in sequence to subject the local furnace body thickness to continuous scouring and thermal shock until the furnace body thickness falls off and melts; One hour after closing the 30# tuyere coal injection gun, the static pressure of the west-facing 11th section furnace body fluctuated violently. The material surface was 2.0m deep after the west foot collapsed. At the same time, the static pressure dropped. When the static pressure fluctuated, the furnace body temperature rose rapidly, and then gradually dropped. The fault was caused by the partial thickening and falling off of the furnace body. The blast furnace did not take other countermeasures and the transition was smooth.

[0030] Example 4 A method for treating local thickening at the lower part of a blast furnace shaft comprises the following steps: (1) Determine the local thickening position of the lower part of the blast furnace shaft according to the difference in the temperature distribution of the cooling wall: The local thickening of the lower part of the blast furnace shaft will lead to the obstruction of heat transfer in the blast furnace, which is intuitively manifested as the furnace body temperature and the cooling wall water temperature of the local thickening position of the lower part of the blast furnace shaft are lower than those of the normal position. According to the difference between the furnace body temperature and the cooling wall water temperature, determine the local thickening position of the lower part of the blast furnace shaft; The temperature of the 25#-27# cooling walls in the 8th and 9th sections of the 1750m³ blast furnace body (the body is divided into 7th to 14th sections from bottom to top) (a 1750m³ blast furnace has 24 tuyere in total, and the positions of the tuyere are horizontally parallel to the 4th section, among which the 1# tuyere is in the north direction and arranged clockwise; the 1# cooling walls in the 8th and 9th sections are in the same direction as the 1# tuyere, and the other cooling walls in the same section are arranged clockwise) is 5-10℃ lower than that of other cooling walls in the same section. It is judged that there is a local thickening in the lower part of the blast furnace body at this location, resulting in a decrease in thermal conductivity, which directly manifests as a lower furnace body temperature than normal; (2) According to the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface is judged, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged; The video and probe inside the 1750m³ blast furnace show that the south probe is shallow and the west probe is deep, with a depth difference of 0.8m. The overall furnace condition is in good condition. The local thickening of the lower part of the blast furnace shaft affects the distribution of local edge airflow. The local thickening of the lower part of the blast furnace shaft on the east side causes the material feeding to be slower than other directions, resulting in uneven material line. Combined with the degree of furnace condition, it is judged that the thickening situation is not serious, and there is no need to expose the thickened parts for manual or mechanical cleaning; (3) Add additional coke to the corresponding throat position just above the local thickening position of the lower part of the blast furnace shaft, and use the local excess additional coke to heat the local thickening position of the lower part of the blast furnace shaft to make up for the heat loss after the local thickening of the lower part of the blast furnace shaft falls off and melts, maintain sufficient heat reserve in the furnace, and avoid abnormal thermal system of the blast furnace. Add additional coke to the furnace at a fixed point from the β angle of the distribution chute to ensure that the coke entering the furnace is the local thickening position of the lower part of the blast furnace shaft. According to the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is selected. For every 1 cooling wall area of ​​the local thickening area of ​​the lower part of the blast furnace shaft, the amount of additional coke is 1 ton, and so on. In the direction of the 25#-27# cooling wall, the temperature of a total of 6 cooling wall areas was abnormal, and 6 tons of additional coke was added using the fixed-point distribution mode; (4) When the additional coke reaches the soft melting zone, the tuyere coal injection gun is closed; the corresponding direction and number of tuyere coal injection guns to be closed are determined according to the location and severity of the local thickening of the lower part of the blast furnace shaft; when the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening of the lower part of the blast furnace shaft is closed; for every three cooling walls of the thickening area, one coal injection gun in the corresponding direction of the local thickening of the lower part of the blast furnace shaft is closed. If the number of closed coal injection guns is more than two, they need to be closed at intervals to avoid causing furnace condition fluctuations; by closing the tuyere coal injection guns at the corresponding parts, the local material feeding speed can be increased, the local edge airflow can be developed, the local high temperature area can be raised, and the thickening parts can be heated. The scouring and temperature rise of the local edge airflow scour and thermally shock the local thickening of the furnace shaft, causing the local thickening of the lower part of the blast furnace shaft to fall off; After 20 batches of materials (materials include ore and coke for smelting, and the mass of one batch of materials in a 1750m³ blast furnace is about 60 tons), 6 tons of additional coke arrive at the soft melting zone, the 13# tuyere coal injection gun (corresponding to cooling wall 26#) is closed, and local edge airflow is developed to scour and thermally shock the thickening, causing the local thickening at the lower part of the blast furnace shaft to fall off; (5) Repeating steps (3) and (4) in sequence to subject the local furnace body thickness to continuous scouring and thermal shock until the furnace body thickness falls off and melts; One hour after closing the No. 13 tuyere coal injection gun, the static pressure of the east-facing 7th section furnace body fluctuated violently. The material surface was 2.7m deep after the east-facing material collapsed. At the same time, the static pressure dropped. When the static pressure fluctuated, the furnace body temperature rose rapidly, and then gradually dropped. The fault was caused by the thickening and falling off of the local furnace body. The blast furnace did not take other countermeasures and the transition was smooth.

[0031] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and such changes or substitutions shall be within the scope of protection of the present invention.

Claims

1. A method for treating local thickening at the lower part of a blast furnace shaft, characterized in that: Additional coke is added at the throat above the local thickening part of the lower part of the blast furnace shaft. When the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening part of the lower part of the blast furnace shaft is closed, and local edge airflow is developed to thermally shock and scour the local thickening part of the lower part of the blast furnace shaft, thereby causing the local thickening part of the lower part of the blast furnace shaft to fall off.

2. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 1, characterized in that: Before adding additional coke, first determine the location of the local thickening in the lower part of the blast furnace shaft and judge the severity of the local thickening in the lower part of the blast furnace shaft.

3. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 2, characterized in that: The location of local thickening in the lower part of the blast furnace shaft is determined based on the difference in temperature distribution of the cooling wall.

4. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 3, characterized in that: When the water temperature of at least one cooling wall in the same section is 3-15° C. lower than the water temperature of other cooling walls in the same section, it is determined that local thickening of the lower part of the blast furnace shaft exists on the cooling wall.

5. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 2, characterized in that: Based on the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface can be judged, and then the severity of the local thickening in the lower part of the blast furnace body can be judged.

6. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 5, characterized in that: When the camera inside the blast furnace detects that there is a depth difference of 0.3-1.2m between two of the probes among the east probe, west probe and south probe, it is necessary to process the local thickness of the lower part of the blast furnace shaft.

7. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 1, characterized in that: The additional coke fed into the furnace adopts a fixed-point distribution mode or a fan-shaped distribution mode. When the local thickening area of ​​the lower part of the blast furnace body is n cooling wall areas, the distribution amount of the additional coke is n tons, n>0.

8. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 1, characterized in that: Every time the thickness area reaches 3 cooling walls, one tuyere coal injection gun below the local thickness of the lower part of the blast furnace shaft is closed. When the number of closed coal injection guns is more than two, the tuyere coal injection guns are closed at intervals.

9. A method for treating local thickening at the lower part of a blast furnace shaft as claimed in claim 1, characterized in that: Additional coke is added at the throat above the local thickening part of the lower part of the blast furnace shaft. When the additional coke reaches the soft melting zone, the tuyere coal injection gun below the local thickening part of the lower part of the blast furnace shaft is closed, and the local edge airflow is developed to perform thermal shock and flushing on the local thickening part of the lower part of the blast furnace shaft. The process is repeated at least once until the local thickening part of the lower part of the blast furnace shaft falls off and melts.

10. A method for treating local thickening at the lower part of a blast furnace shaft according to claim 1, characterized in that: The steps include: (1) Determine the location of local thickening in the lower part of the blast furnace shaft based on the difference in temperature distribution of the cooling wall; (2) According to the performance of the camera and probe inside the blast furnace, the condition of the blast furnace charge surface is judged, and then the severity of the local thickening in the lower part of the blast furnace shaft is judged; (3) Adding additional coke to the corresponding throat position just above the local thickening position of the lower part of the blast furnace shaft, and using the local excess additional coke to heat the local thickening position of the lower part of the blast furnace shaft to compensate for the heat loss after the local thickening of the lower part of the blast furnace shaft falls off and melts; (4) When the additional coke reaches the soft melting zone, the tuyere coal injection guns below the local thickening of the lower part of the blast furnace shaft are closed; according to the location and severity of the local thickening of the lower part of the blast furnace shaft, the corresponding direction and number of tuyere coal injection guns to be closed are determined; when the additional coke reaches the soft melting zone, the tuyere coal injection guns below the local thickening of the lower part of the blast furnace shaft are closed; (5) Repeating steps (3) and (4) in sequence causes the local thickness of the lower part of the blast furnace shaft to be subjected to continuous scouring and thermal shock until the thickness of the shaft falls off and melts.