Method for correcting serious deviation of circumferential descending speed of blast furnace burden surface

Abstract

The invention relates to the technical field of blast furnace smelting, in particular to a method for correcting severe deviation of circumferential descending speed of a blast furnace charge level, which comprises the following steps: increasing the air inlet rate of a fast blanking area to slow down the blanking speed of the fast blanking area until the descending speed of the charge level is circumferentially uniform; or, the air inlet amount of the slow discharging area is reduced, so that the discharging speed of the slow discharging area is increased till the downward speed of the material level is uniform in the circumferential direction; or the air inlet amount of the fast discharging area is increased and the air inlet amount of the slow discharging area is reduced at the same time until the downward speed of the material level is uniform in the circumferential direction. According to the method, a traditional blast furnace charge level deviation mechanism is overturned, a tuyere layout adjustment strategy opposite to a traditional method is adopted, and the charge level deviation problem occurring in the blast furnace production process is successfully solved. No matter a small blast furnace or a large blast furnace, the stock rod deviation is obviously improved by implementing the method disclosed by the invention, and the deviation value is greatly reduced to be within a reasonable range (lt); 300mm), and can be kept stable for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, and in particular to a method for correcting a serious deviation in the circumferential downward speed of a blast furnace material surface. Background Art

[0002] The blast furnace is a vertical furnace countercurrent reactor. The raw materials (sintering + pellets + lump ore + coke) added from the top of the furnace are acted upon by the high-temperature reducing gas flowing upward in the countercurrent (the reducing gas is the air blown in by the blower, which is heated by the hot blast furnace and enters the blast furnace through the tuyere, where it reacts with the coke in the blast furnace to generate coal gas). They are continuously heated, decomposed, reduced, softened, melted, dripped, carburized, and finally form a slag-iron melt and separate. The blast furnace production process is continuous, with materials continuously being loaded from the top of the furnace and iron continuously being tapped from the taphole below.

[0003] The operation status of a blast furnace is difficult to see directly, but it can be judged through relevant parameters. The parameters that can characterize the operation status of a blast furnace include: cold air flow, cold air pressure, hot air pressure, furnace top pressure, hot air temperature, furnace body temperature, furnace top temperature, material level probe downward condition, furnace body static pressure, etc. Among them, the data on the furnace top that can most directly reflect the operation status of a blast furnace is the material level downward condition.

[0004] Blast furnaces are generally equipped with two probes at 180° intervals in the circumferential direction (some medium and large blast furnaces are equipped with three probes at 120°). The charge moves from top to bottom in the blast furnace, and the probe moves steadily and evenly downward along with the charge surface. Under normal circumstances, the descending speed of the two probes is basically equal, and the depths measured by the probes are basically close. Occasionally, there is a deviation within 0.3m. However, during the operation of the blast furnace, due to the influence of various factors: such as uneven circumferential erosion of the furnace wall or uneven thickness of the slag skin on the furnace wall, unreasonable layout of the tuyere, uneven circumferential iron tapping, uneven distribution of the furnace top, etc., it may cause uneven material discharge speed, resulting in huge deviations in the measured values ​​of the two probes, such as a deviation of 1.5-2.0m or even greater.

[0005] When the deviation of the two probes of the blast furnace is ≤0.3m, generally no adjustment is required. The blast furnace can automatically correct the deviation during operation to make the material surface gradually uniform. When the deviation of the two probes is 0.3-0.6m, the blast furnace can correct the deviation of the probes by adjusting the charging system at the top, changing the distribution matrix, and improving the quality of raw materials and fuels to increase the blast furnace air volume, increase the blast kinetic energy, and activate the center of the blast furnace. However, when the blast furnace has a serious deviation in the downward direction of the probe, the deviation of the two probes is ≥0.6m and sometimes even reaches 2.0 or more, indicating that there is a major problem in the operation of the blast furnace, and the above methods can no longer solve the problem of probe deviation. In order to correct the deviation of the probe, it is necessary to adjust the circumferential airflow of the blast furnace. The traditional treatment methods are basically the following measures: ① Reduce the air inlet area of ​​the tuyere at the circumferential position of the fast material discharge; ② Block 1-2 tuyere at the circumferential position of the fast material discharge area to limit the air intake in this area; ③ Use tuyere with longer length in the fast material discharge area; ④ Use fan-shaped cloth, and spread more cloth at the circumferential position of the fast material discharge to fill the space in this area, so that the two probes are flush. The overall idea of ​​the first three methods here is to reduce the air intake in the fast material discharge area and reduce the combustion reaction of coke in this area to slow down the material discharge speed. However, this method often backfires in production practice and has the opposite effect; the fourth method uses fan-shaped cloth to supplement materials, but does not solve the fundamental problem of too fast material discharge, which is a temporary solution.

[0006] The above traditional methods cannot solve the problem of material surface deviation encountered in blast furnace production. On the contrary, they will aggravate the deterioration trend of the blast furnace, leading to blast furnace malfunction and further aggravation of blast furnace losses. Therefore, the present invention subverts the traditional cognition through the study of the mechanism of blast furnace material surface deviation, and can effectively prevent blast furnace material surface deviation. Summary of the invention

[0007] The present invention aims to solve the above-mentioned problems and proposes a method for correcting the serious deviation of the circumferential downward speed of the blast furnace charge surface. By reasonable lower adjustment, the circumferential deviation of the blast furnace charge surface is corrected, so that the circumference of the blast furnace is uniform and stable, thereby achieving stable operation of the blast furnace and energy saving and consumption reduction.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for correcting a serious deviation in the circumferential downward velocity of a blast furnace charge surface, characterized in that the method comprises:

[0010] Increase the air intake in the fast-feeding area to slow down the material feeding speed in this area until the material surface downward speed is uniform in the circumferential direction;

[0011] Alternatively, the air intake in the slow material feeding area is reduced to speed up the material feeding speed in the slow material feeding area until the material surface downward speed is uniform in the circumferential direction;

[0012] Alternatively, the air intake in the area where the material is discharged quickly is increased and the air intake in the area where the material is discharged slowly is reduced at the same time until the downward speed of the material surface is uniform in the circumferential direction.

[0013] As a further optimization scheme of the present invention, a method for increasing the air intake volume in the fast material discharge area includes: expanding the air intake area of ​​the air outlet in the fast material discharge area.

[0014] As a further optimization scheme of the present invention, a method for expanding the air inlet area of ​​the tuyere in the fast material discharge area includes: increasing the diameter of the tuyere in the fast material discharge area.

[0015] As a further optimization scheme of the present invention, the method of reducing the air intake volume in the slow material feeding area includes: reducing the air inlet area of ​​the tuyere in the slow material feeding area and / or using a longer tuyere in the slow material feeding area.

[0016] Among them, the use of long air vents can make the air in this area blow more toward the center, which correspondingly reduces the air volume in the edge area, which is beneficial to reduce or eliminate the pipeline stroke in this area, stabilize the gas flow, thereby reducing the resistance of the gas flow in this area to the material column, and promote the reduction of raw materials and restore the normal feeding speed.

[0017] As a further optimization scheme of the present invention, the method of reducing the air inlet area of ​​the tuyere in the slow material feeding area includes: reducing the number of tuyere in the slow material feeding area and / or reducing the diameter of the tuyere in the slow material feeding area.

[0018] As a further optimization scheme of the present invention, a method for reducing the number of air vents in the slow material feeding area includes: directly blocking some of the air vents.

[0019] As a further optimization scheme of the present invention, after the downward speed of the blast furnace charge surface is uniform in the circumferential direction, the blocked tuyere are opened one by one.

[0020] As a further optimization scheme of the present invention, during the blast furnace shutdown procedure, the fast-feeding area and the slow-feeding area are corrected.

[0021] The mechanism of blast furnace charge surface deviation is analyzed as follows:

[0022] The traditional concept is that the reasons for uneven circumference of the blast furnace and fast local material discharge are: the air intake of the corresponding lower space in the area where the material is discharged too quickly is larger than that in other circumferential areas, so the coke combustion reaction is more intense, and it is easier to form a coke empty area, which speeds up the material discharge; at the same time, the rising gas volume in this area is large, the chemical reaction is more than other areas, the melting of the charge is accelerated, resulting in a fast drop of the charge in this area; at the same time, there is also a phenomenon: the area with fast material discharge has a long tapping time at the corresponding iron mouth. Therefore, the traditional methods for correcting the deviation of the material surface are basically the following measures: ① Reduce the air inlet area of ​​the tuyere at the circumferential position where the material is discharged quickly; ② Block 1-2 tuyere at the circumferential position where the material is discharged quickly to limit the air intake in this area; ③ Use a longer tuyere in the area where the material is discharged quickly; ④ Use fan-shaped distribution, and distribute more material at the circumferential position where the material is discharged quickly to fill the space in this area, so that the two probes are flush. The general idea of ​​the first three methods is to reduce the air intake in the fast feeding area to reduce the amount of coke burned in this area and reduce the amount of chemical reaction in this area to slow down the feeding speed. The fan-shaped distribution in the fourth method can only solve the temporary problem and will be restored in a short time. This method of correcting the deviation of the material surface often goes against one's will in production practice. The reason is that the mechanism of the deviation of the material surface is misunderstood.

[0023] The present invention corrects the mechanism of the deviation of the material surface in the medium and high blast furnaces, and its main viewpoints are: ① The coal gas flow at a certain circumferential position of the blast furnace is too large, resulting in a pipeline stroke at this position or the upper area of ​​this position, generating a force opposite to the direction of material descent, so that the material discharge in the furnace top area corresponding to the circumferential position of the blast furnace is slowed down. ② The iron mouth at the position with pipeline airflow is prone to splashing when exposed to the wind, making it difficult to tap iron. Therefore, according to this mechanism, the air intake at the circumferential position is too large, which leads to slow material discharge in this area, and due to the pipeline airflow in this area, the iron mouth in the high area is prone to splashing, so less iron is tapped. In the opposite direction, the material discharge is fast, the iron mouth is not easy to splash, and more iron is tapped. Therefore, the circumferential position with fast material discharge has weak airflow and less air intake, rather than more air intake. This mechanism subverts traditional cognition, and in correcting the deviation of the material surface, it uses measures that are exactly opposite to the traditional adjustment of the tuyere layout.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention successfully solves the problem of material surface deviation in the blast furnace production process by overturning the traditional blast furnace material surface deviation mechanism and adopting a tuyere layout adjustment strategy that is opposite to the traditional method. Whether it is a small blast furnace or a large blast furnace, by implementing the method of the present invention, the probe deviation is significantly improved, the deviation value is greatly reduced to a reasonable range (<300mm), and remains stable for a long time. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions of the present invention, preferred implementation schemes of the present invention are described below in conjunction with specific examples to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0027] Various factors in blast furnaces cause huge deviations between the two probes, sometimes even 1.5-2.0m, or even larger. At this time, it is difficult to correct the probe deviation by simply improving the quality of raw materials and fuels, adjusting the furnace top charging system, and improving the wind pressure, wind volume, and wind temperature. For this reason, the layout of the tuyere must be adjusted. The specific implementation steps are:

[0028] (1) Prepare several tuyere sleeves with different diameters. For example, if the normal tuyere sleeve diameter is 110mm, prepare 5-8 tuyere sleeves with diameters of 105mm and 115mm respectively. Prepare 3-4 tuyere sleeves that are 40mm longer than the normal ones. For example, if the normal tuyere sleeve length is 560mm, prepare 3-4 tuyere sleeves with a sleeve diameter of 105mm and a tuyere length of 600mm.

[0029] (2) Keep the blast furnace running smoothly as much as possible, ensure that the furnace temperature is sufficient, and the molten iron temperature is 1480-1520℃. At the same time, increase the slag MgO / Al2O3 (mass ratio) by 0.65-0.75 to prepare for the smooth shutdown of the blast furnace.

[0030] (3) The blast furnace is shut down according to normal short-term shutdown procedures.

[0031] (4) Take advantage of the wind break opportunity to adjust the layout of different air outlets: either increase the air intake in the area; or reduce the air intake in the slow material feeding area; or take the above measures at the same time. Among them, the method of increasing the air intake in the fast material feeding area includes: expanding the air intake area of ​​the air outlet in the fast material feeding area. Further, the method of expanding the air intake area of ​​the air outlet in the fast material feeding area includes: increasing the diameter of the air outlet in the fast material feeding area. The method of reducing the air intake in the slow material feeding area includes: reducing the air intake area of ​​the air outlet in the slow material feeding area and / or using longer air outlets in the slow material feeding area. Further, the method of reducing the air intake area of ​​the air outlet in the slow material feeding area includes: reducing the number of air outlets in the slow material feeding area and / or reducing the diameter of the air outlet in the slow material feeding area. Further, the method of reducing the number of air outlets in the slow material feeding area includes: directly blocking some air outlets.

[0032] (5) After the circumferential layout of the air-free tuyere is adjusted, the blast furnace resumes air supply. After the blast furnace charge level is corrected and the probe deviation is within the normal range, the blocked tuyere is opened one by one.

[0033] Example 1

[0034] The effective volume of a blast furnace is 1400m 3, there are 22 tuyere and 2 iron ports in the lower part, which are opened in the 180° direction, namely the east iron port and the west iron port; there are 2 mechanical probes on the top of the furnace, which correspond to the circumferential positions of the east and west iron ports, respectively, namely the east probe and the west probe; the diameter of the tuyere is mainly 115mm. The blast furnace operated stably in the first two years of production. However, two years later, the blast furnace experienced fluctuations to varying degrees, with collapsed and suspended materials in the blast furnace, the air volume remained at a low level for a long time, and the tuyere sleeve was frequently damaged. The measurement values ​​of the east and west probes differed by 1500-2000mm. The east material ruler with a low measurement value had little change in the measurement value for a long period of time, and the material ruler data only showed a sharp increase when the material collapsed. The blast furnace was difficult to maintain normal production, and had to be shut down, the furnace cylinder was removed, and the furnace body was sprayed before restarting. After the restart, the blast furnace operated basically normally for a short period of time. After two months of production, the blast furnace fell into a passive situation again. To this end, the traditional material surface deviation mechanism was overturned. By adopting a tuyere layout that was contrary to traditional cognition, the misunderstanding was overcome, the deviation was corrected, and the blast furnace gradually got out of the predicament.

[0035] In order to correct the deviation, the traditional method was used to adjust the tuyere layout: (1) The west probe was feeding faster, while the east probe was almost not moving. The west probe was 1500-2000mm deeper than the east probe. The east probe only showed a sharp increase in value when the material collapsed. After the fan-shaped material was used to correct the material surface height, the material size soon showed a sharp deviation again after the normal material feeding was restored. (2) Five (3) One vent on the west side was blocked for a long time, and even three vents were blocked in this area many times; the east side was not used. (4) The west side has blocked tuyere, the air inlet area is small, but the iron-outlet time is long and the iron-outlet is large; the east side has unblocked tuyere, the air inlet area is large, but the iron-outlet is small. (5) The top temperature on the west side is low, but obvious flames can be seen on the top of the furnace in this area; the top temperature on the east side is high, but no flames can be seen on the top of the furnace in this area.

[0036] The above traditional cognition cannot solve the material surface deviation, on the contrary it becomes more and more serious. Therefore, the following adjustments are made:

[0037] (1) Prepare several tuyere sleeves with different diameters. The normal tuyere sleeve of the blast furnace has a diameter of 110 mm. Prepare 6 tuyere sleeves with diameters of 105 mm and 115 mm. Prepare several tuyere sleeves with different lengths. The normal tuyere length of the blast furnace is 560 mm. Prepare 4 tuyere sleeves with a diameter of 105 mm and a length of 600 mm.

[0038] (2) Keep the blast furnace running smoothly as much as possible, ensure sufficient furnace temperature, ensure the molten iron temperature is 1490℃, and increase the slag MgO / Al2O3 (mass ratio) to 0.75. Prepare for the smooth shutdown of the blast furnace.

[0039] (3) The blast furnace is shut down according to normal short-term shutdown procedures.

[0040] (4) Taking advantage of the wind stop opportunity, the blast furnace adjusted the layout of different tuyere diameters: ① Open the west side (faster material discharge) to block the tuyere, and The three diameters of the tuyere are enlarged to Increase the air intake area on the west side. ② Block one air outlet on the east side (slow material discharge) to reduce the air intake area in this area. ③ Use 3 air outlets with a length of 600mm on the east side (slow material discharge).

[0041] (5) After the adjustment of the circumferential layout of the tuyere is completed, the blast furnace resumes air supply. After the blast furnace charge surface is corrected and the probe deviation is ≤300mm, the blocked tuyere is opened. Among them, step (4) is to make the material discharge speed of the east side (slow material discharge) faster and slightly faster than the west side through a slight transition correction. After the material surface is gradually corrected, the blocked tuyere is opened again to slow down the material discharge speed slightly and keep it balanced with the east side.

[0042] The above adjustments have achieved significant results:

[0043] (1) The probe gradually levels off, with occasional small differences but all within a reasonable range (<300mm), and there is no need to use fan-shaped cloth.

[0044] (2) The iron tapping on the east and west sides is normal, and the values ​​of parameters such as iron tapping amount, iron tapping time, and molten iron temperature are close.

[0045] (3) The temperatures of the furnace tops on the east and west sides gradually approach each other, and the curves occasionally have intersections.

[0046] (4) The difference in static pressure between the upper part of the furnace body on the east and west sides is reduced.

[0047] (5) The blast furnace is subject to an increase in top pressure and pressure difference, the air volume increases significantly, and the blast furnace runs smoothly and stably.

[0048] After the adjustment of the blast furnace, great progress has been made in various technical and economic indicators (see Table 1 below for a comparison of various technical and economic indicators before and after implementation).

[0049] Table 1

[0050] project Probe deviation Utilization coefficient Focal Ratio Coal ratio Fuel ratio unit mm t / m3.d kg / t kg / t kg / t Before implementation 1800 2.3 450 121 571 After implementation 20 3.5 401 123 524 Out of tolerance -1780 1.2 -49 2 -47 project Gas utilization rate Pig iron cost Oxygen enrichment rate Furnace top temperature Weekly suspension times unit ％ Yuan / t ％ ℃ Second-rate Before implementation 41 2936 1.5 210 8 After implementation 46 2705 6 130 0 Out of tolerance 5 -231 4.5 -80 -8

[0051] Example 2

[0052] The effective volume of a blast furnace is 2800m 3, there are 28 tuyere in the lower part, and 4 iron mouths, which are evenly opened along 90°, namely the east iron mouth, south iron mouth, west iron mouth and north iron mouth; there are 2 mechanical probes on the top of the furnace, corresponding to the circumferential positions of the south and north iron mouths, respectively, the south probe and the north probe; the diameter of the tuyere is mainly 120mm. The blast furnace operated stably in the first three years of production. However, three years later, the blast furnace experienced fluctuations to varying degrees, with collapsed and suspended materials in the blast furnace, the air volume was at a low level for a long time, and the tuyere sleeve was frequently damaged. The difference between the south and north probes was 1500-2000mm. The low-measured south material ruler had little change in the measured value for a long period of time, and the material ruler data only showed a sharp increase when the material collapsed. The blast furnace was difficult to maintain production, and had to be shut down, the furnace cylinder was removed, and the furnace body was sprayed before restarting. After the restart, the blast furnace operated basically normally for a short period of time. After two months of production, the blast furnace fell into a passive situation again. To this end, the traditional material surface deviation mechanism was overturned. By adopting a tuyere layout that was contrary to traditional cognition, the misunderstanding was overcome, the deviation was corrected, and the blast furnace gradually got out of the predicament.

[0053] In order to correct the deviation, the traditional method was used to adjust the tuyere layout: (1) The north probe was feeding faster, while the south probe was almost not moving. The north probe was 1500-2000mm deeper than the south. The south probe only showed a sharp increase in value when the material collapsed. After the fan-shaped material was used to correct the material surface height, the material size soon showed a sharp deviation again after the normal material feeding was restored. (2) Four (3) One air vent in the north was blocked for a long time, and even two air vents were blocked in this area many times; there was no air vent in the south. (4) The air inlet on the north is blocked, the air inlet area is small, but the iron outlet on the north takes a long time to produce more iron; the air inlet on the south is not blocked, the air inlet area is large, but less iron is produced. The iron outlet is easily splashed by the wind. (5) The top temperature on the north side is low, but obvious flames can be seen on the top of the furnace in this area; the top temperature on the south side is high, but no flames can be seen on the top of the furnace in this area. The above traditional cognition cannot solve the deviation of the material surface, on the contrary, it becomes more and more serious. Therefore, the following adjustments are made:

[0054] (1) Prepare several tuyere sleeves with different diameters. The normal tuyere sleeve of the blast furnace has a diameter of 120 mm. Prepare 6 tuyere sleeves with diameters of 115 mm and 125 mm respectively. Prepare several tuyere sleeves with different lengths. The normal tuyere sleeve of the blast furnace has a minimum length of 600 mm. Prepare 4 tuyere sleeves with a diameter of 115 mm and a length of 640 mm.

[0055] (2) The blast furnace should be kept running smoothly as far as possible to ensure that the furnace temperature is sufficient and the molten iron temperature is 1500°C. At the same time, the MgO / Al2O3 (mass ratio) of the slag should be increased to 0.7 to prepare for the smooth shutdown of the blast furnace.

[0056] (3) The blast furnace is shut down according to normal short-term shutdown procedures.

[0057] (4) Taking advantage of the wind stop opportunity, the blast furnace adjusted the layout of different tuyere diameters: ① Open the north side (faster material discharge) to block the tuyere, and The three diameters of the tuyere are enlarged to Increase the air intake area on the north side. ② Block an air outlet on the south side (slow material discharge) to reduce the air intake area in this area. ③ Use 3 air outlets with a length of 640mm on the south side (slow material discharge).

[0058] (5) After the circumferential layout of the tuyere is adjusted, the blast furnace resumes air supply. After the blast furnace charge surface is corrected and the deviation of the probe is ≤300mm, the blocked tuyere is opened.

[0059] The above adjustments have achieved significant results:

[0060] (1) The probe gradually levels off. Occasionally there are small differences, but they are all within a reasonable range (<300mm). There is no need for fan-shaped distribution.

[0061] (2) The iron discharge from the north and south sides is normal, and the iron discharge amount, iron discharge time, and molten iron temperature are similar.

[0062] (3) The temperatures of the furnace tops on the north and south sides gradually approach each other, and the curves occasionally have intersections.

[0063] (4) The difference in static pressure on the upper part of the furnace body on the north and south sides is reduced.

[0064] (5) The blast furnace is subject to an increase in top pressure and pressure difference, the air volume increases significantly, and the blast furnace runs smoothly and stably.

[0065] After the adjustment of the blast furnace, great progress has been made in various technical and economic indicators (see Table 2 below for a comparison of various technical and economic indicators before and after implementation).

[0066] Table 2

[0067]

[0068]

[0069] As can be seen from Table 1 and Table 2, by implementing the method of the present invention, the deviation of the probe has been significantly improved, and the deviation value has been greatly reduced to a reasonable range. After correcting the deviation of the charge surface, the utilization coefficient of the blast furnace has been significantly improved, and the coke ratio and fuel ratio have both decreased, which means that more molten iron can be produced in the same production time, while the consumption of raw materials and energy is reduced, reducing production costs. In addition, the gas utilization rate of the blast furnace is improved, the cost of pig iron is reduced, and the economic benefits are further improved.

[0070] In summary, the present invention subverts the traditional blast furnace charge surface deviation mechanism and adopts a reasonable tuyere layout adjustment strategy to successfully solve the charge surface deviation problem in blast furnace production, improve the stability and smoothness of blast furnace operation, reduce production costs, and improve economic benefits, which has important promotion and application value.

[0071] According to the description of the present invention, those skilled in the art can easily use the method of the present invention to correct the serious deviation of the circumferential downward speed of the blast furnace charge surface, and can produce the positive effects recorded in the present invention.

[0072] The above is only a preferred embodiment of the present invention, but the present invention is not limited to the above specific embodiments. Those skilled in the art may make some modifications, supplements or use similar methods instead without departing from the principle of the present invention, which should also be regarded as the protection scope of the present invention.

Claims

1. A method for correcting a serious deviation in the circumferential downward velocity of a blast furnace charge surface, characterized in that: The method comprises: Increase the air intake in the fast-feeding area to slow down the material feeding speed in this area until the material surface downward speed is uniform in the circumferential direction; Alternatively, the air intake in the slow material feeding area is reduced to speed up the material feeding speed in the slow material feeding area until the material surface downward speed is uniform in the circumferential direction; Alternatively, the air intake in the area where the material is discharged quickly is increased and the air intake in the area where the material is discharged slowly is reduced at the same time until the downward speed of the material surface is uniform in the circumferential direction.

2. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 1 is characterized in that: Methods for increasing the air intake volume in the fast material discharge area include: expanding the air intake area of ​​the air outlet in the fast material discharge area.

3. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 2, characterized in that: Methods for expanding the air inlet area of ​​the tuyere in the fast material discharge area include: increasing the diameter of the tuyere in the fast material discharge area.

4. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 1 is characterized in that: Methods for reducing the air intake volume in the slow material feeding area include: reducing the air intake area of ​​the tuyere in the slow material feeding area and / or using a longer tuyere in the slow material feeding area.

5. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 4 is characterized in that: The method of reducing the air inlet area of ​​the tuyere in the slow material feeding area includes: reducing the number of tuyere in the slow material feeding area and / or reducing the diameter of the tuyere in the slow material feeding area.

6. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 5, characterized in that: Methods to reduce the number of tuyere in the slow material feeding area include: directly blocking some tuyere.

7. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 6, characterized in that: After the downward speed of the blast furnace material surface is uniform in the circumferential direction, open the blocked tuyere one by one.

8. The method for correcting the serious deviation of the circumferential downward velocity of the blast furnace charge surface according to claim 1, characterized in that: During the blast furnace shutdown procedure, corrections are made to the fast and slow material feeding areas.

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