Treatment method for bonding of blast furnace wall body

Abstract

The invention relates to a blast furnace wall bonding treatment method which comprises the following steps: S1, controlling the charging proportion of high-zinc furnace charge, discharging zinc by utilizing central airflow, and reducing the gathering of zinc in the furnace; s2, the air temperature and the oxygen enrichment rate are increased, so that the theoretical combustion temperature in the furnace is increased, the combustion rate of pulverized coal is increased, the yield of the blast furnace is increased, fuel consumption is reduced, and the retention time of the zinc element in the blast furnace is shortened; s3, increasing the operation pressure difference; on the basis of high pressure difference, full-wind operation is carried out, and a high wind speed is kept, so that enough central airflow can be ensured in the blast furnace; s4, the furnace temperature and the air inlet speed are increased; the blast furnace wall body stickers are severely scoured by the airflow, so that the stickers rapidly fall off; and S5, wall body temperature monitoring. The problems of wall bonding, nodulation and the like in the long-term operation process of the blast furnace can be effectively solved, so that the operation efficiency of the blast furnace is improved, and the service life is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnaces, and in particular to a method for treating blast furnace wall adhesion. Background Art

[0002] At present, as the steel market price continues to fall and the pressure on production costs gradually increases, the use of waste resources such as dust and sludge with high zinc content is increasing day by day. Although this can reduce the cost of ironmaking, it will lead to an increase in the zinc load of blast furnace charges.

[0003] Zinc compounds will be reduced in the high temperature area of ​​more than 1000℃ in the blast furnace, and gasify into zinc vapor (the boiling point of zinc is 907℃), then rise with the coal gas, and condense when reaching the lower temperature area at the top of the blast furnace (the melting point of zinc is 420℃), and are mostly oxidized into fine particles of zinc oxide by H, O, CO, etc. in the coal gas, part of which adheres to the descending charge and enters the high temperature area again, and the other part forms a binder on the blast furnace wall along with the impurities and slag in the raw materials, and this cycle repeats, forming a circulation accumulation of zinc in the blast furnace. When zinc circulates and enriches to a certain extent in the blast furnace, the blast furnace wall will form a bond, resulting in a reduction in the effective volume of the blast furnace, hindered heat transfer, and reduced smelting efficiency. In severe cases, it may even affect the normal operation of the blast furnace. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method for treating blast furnace wall adhesion, which can effectively solve the problems of wall adhesion, nodules, etc. during the long-term operation of the blast furnace, thereby improving the operation efficiency of the blast furnace and extending its service life.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for treating blast furnace wall adhesion proposed by the present invention comprises the following steps:

[0007] S1. Control the proportion of high-zinc charge entering the furnace, use the central airflow to discharge zinc, and reduce the accumulation of zinc in the furnace;

[0008] S2. Increase the wind temperature and oxygen enrichment rate to increase the theoretical combustion temperature in the furnace and the combustion rate of pulverized coal, thereby increasing the output of the blast furnace and reducing fuel consumption, and shortening the residence time of zinc in the blast furnace;

[0009] S3. Increase the operating pressure difference; on the basis of high pressure difference, operate with full wind and maintain a high wind speed to ensure sufficient central airflow inside the blast furnace;

[0010] S4. Increase the furnace temperature and air velocity; make the airflow scour the adhesive on the blast furnace wall violently, causing the adhesive to fall off quickly;

[0011] S5. Wall temperature monitoring.

[0012] Furthermore, the step S1 specifically includes: controlling the zinc load of the charge into the furnace to ≤0.3kg / t, and at the same time adjusting the distribution system to develop the central airflow to discharge zinc and reduce the accumulation of zinc in the furnace; loosening the edge airflow and controlling the edge airflow not to be too strong to ensure the smooth operation of the blast furnace.

[0013] Furthermore, the step S2 specifically includes: increasing the wind temperature to 1150-1250° C., reducing the height of the soft melting zone, increasing the proportion of blocky strip material columns, and discharging zinc through the coal gas flow; and increasing the oxygen enrichment rate to above 4.0%.

[0014] Furthermore, in step S3, the increase in the pressure difference meets the following prerequisites: the wind pressure is stable, the furnace charge drops normally, there is an upper limit value, and the increase does not exceed 10% of the normal pressure difference.

[0015] Furthermore, the step S4 specifically includes: taking advantage of the wind stop opportunity to reduce the tuyere, reduce the tuyere area by 8-12%, increase the depth of the whirlpool zone, and reduce the dead material column in the center of the furnace; at the same time, in the process of restoring the furnace condition, the furnace temperature is controlled at a higher level between 1.0-1.5%, and the inlet wind speed reaches more than 260m / s; under the action of blast furnace temperature and high wind speed, the airflow violently scours the adhesive on the blast furnace wall, causing it to fall off quickly.

[0016] Furthermore, the step S5 specifically includes: after processing the wall adhesion, continue to monitor the various parameters of the blast furnace and the temperature changes of the cooling wall. Once an abnormal situation is found, it should be adjusted and processed in time to maintain a reasonable furnace type. At the same time, it is also necessary to continuously optimize and improve the batching structure and operating parameters of the blast furnace to ensure that the slag basicity is around 1.20, and at the same time control the excessive pressure difference to return it to normal pressure difference.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention can successfully consume low-cost furnace materials, reduce ironmaking costs, utilize waste resources, and reduce environmental pollution.

[0019] 2. In the case of blast furnace wall adhesion, ensure the smooth operation of the blast furnace, avoid fluctuations in furnace conditions, and reduce production losses.

[0020] 3. Avoid centralized coke addition and furnace washing, save coke consumption, and reduce the coke ratio of blast furnaces.

[0021] 4. Improve smooth operation, protect blast furnace equipment and extend maintenance cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the longitudinal and transverse sections inside the blast furnace when the blast furnace wall is bonded;

[0023] Figure 2 It is a schematic diagram of the longitudinal and transverse sections inside the blast furnace after being treated by the method of the present invention. DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] The present invention proposes a method for treating blast furnace wall adhesion, and the specific implementation process is as follows:

[0026] S1. Control the proportion of high-zinc charge entering the furnace, use the central airflow to discharge zinc, and reduce the accumulation of zinc in the furnace;

[0027] Control the zinc load of the charge to ≤0.3kg / t (national standard ≤0.15kg / t) to prevent the wall from sticking. At the same time, adjust the distribution system, develop the central airflow (the central temperature of the infrared image of the furnace top is above 500℃) to discharge zinc and reduce the accumulation of zinc in the furnace. Appropriately loosen the edge airflow and control the edge airflow not to be too strong (the edge temperature of the infrared image of the furnace top is below 150℃), which can ensure the smooth operation of the blast furnace.

[0028] S2. Increase the wind temperature and oxygen enrichment rate to increase the theoretical combustion temperature in the furnace and the combustion rate of pulverized coal, thereby increasing the output of the blast furnace and reducing fuel consumption, and shortening the residence time of zinc in the blast furnace;

[0029] Increase the air temperature to 1150-1250℃, reduce the height of the soft melting zone, increase the proportion of blocky strip material columns, and discharge zinc through the coal gas flow. Increase the oxygen enrichment rate to more than 4.0%, effectively improving smelting efficiency and output. The above operations can increase the theoretical combustion temperature in the furnace, increase the combustion rate of coal powder, thereby increasing the output of the blast furnace and reducing fuel consumption, and shortening the residence time of zinc elements in the blast furnace.

[0030] Since the increase of oxygen enrichment rate will lead to the increase of theoretical combustion temperature in front of the tuyere, thus affecting the distribution of coal gas flow in the furnace and the stability of furnace conditions, it is necessary to accurately control the oxygen enrichment rate during blast furnace operation, adjust the operating wind pressure of the blast furnace, ensure the normal descent of the charge, and avoid the intensification of the contradiction between the air permeability in the furnace and the movement of coal gas flow.

[0031] S3. Increase the operating pressure difference; on the basis of high pressure difference, operate with full wind and maintain a high wind speed to ensure sufficient central airflow inside the blast furnace;

[0032] Due to the adhesion of the wall, the edge airflow is weak, so the pressure difference increases, and edge airflow and edge pipes will not be generated. However, there are three prerequisites for increasing the pressure difference: first, the wind pressure must be stable; second, the furnace charge can drop normally; third, there must be an upper limit; the pressure difference increase generally does not exceed 10% of the normal pressure difference. On the basis of high pressure difference, try to run at full wind and maintain a high wind speed to ensure sufficient central airflow inside the blast furnace.

[0033] S4. Increase the furnace temperature and air velocity; make the airflow scour the adhesive on the blast furnace wall violently, causing the adhesive to fall off quickly;

[0034] Take advantage of the wind stop opportunity to reduce the tuyere, reduce the tuyere area by 8-12%, increase the depth of the whirlpool zone, reduce the dead material column in the center of the hearth, make the hearth more active, make the primary airflow distribution more reasonable, and make the blast furnace reaction more complete.

[0035] At the same time, in the process of restoring the furnace condition, the furnace temperature is controlled at a higher level of 1.0-1.5%, the air inlet speed reaches more than 260m / s, and the tuyere is opened under the premise of ensuring high wind speed. Under the "double high" means of blast furnace temperature and high wind speed, the airflow violently flushes the adhesive on the blast furnace wall, causing it to fall off quickly, so that the adhesion of the furnace wall is completely cured.

[0036] S5. Wall temperature monitoring;

[0037] After dealing with the wall adhesion, it is necessary to continue to monitor the various parameters of the blast furnace and the temperature changes of the cooling wall. Once an abnormal situation is found, it should be adjusted and handled in time to maintain a reasonable furnace type. At the same time, it is also necessary to continuously optimize and improve the blast furnace's batching structure and operating parameters to ensure that the slag basicity is around 1.20, and at the same time control the high pressure difference to return it to normal pressure difference, so as to improve the production efficiency and stability of the blast furnace.

[0038] The above method can quickly deal with the adhesion of the blast furnace wall. Its working principle is to ensure the activity of the furnace hearth and allow the blast furnace to absorb a higher air volume. With the air volume, there will be enough gas volume and gas flow rate, and the wall adhesive will naturally fall off under the action of the strong gas flow. The zinc and zinc oxide that have not formed adhesion are discharged out of the furnace with the strong gas flow, blocking the source of the adhesive, and the blast furnace wall adhesion can be successfully treated. During the treatment process, due to the obstruction of the adhesive to the edge airflow, the blast furnace pressure difference will increase, so it is necessary to control the pressure difference to ensure the smooth operation of the blast furnace.

[0039] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for treating blast furnace wall adhesion, characterized in that: The method comprises the following steps: S1. Control the proportion of high-zinc charge entering the furnace, use the central airflow to discharge zinc, and reduce the accumulation of zinc in the furnace; S2. Increase the wind temperature and oxygen enrichment rate to increase the theoretical combustion temperature in the furnace and the combustion rate of pulverized coal, thereby increasing the output of the blast furnace and reducing fuel consumption, and shortening the residence time of zinc in the blast furnace; S3. Increase the operating pressure difference; on the basis of high pressure difference, operate with full wind and maintain a high wind speed to ensure sufficient central airflow inside the blast furnace; S4. Increase the furnace temperature and air velocity; make the airflow scour the adhesive on the blast furnace wall violently, causing the adhesive to fall off quickly; S5. Wall temperature monitoring.

2. A method for treating blast furnace wall adhesion according to claim 1, characterized in that: The step S1 specifically includes: controlling the zinc load of the charge into the furnace to be ≤0.3kg / t, and at the same time adjusting the charge distribution system to develop the central airflow to discharge zinc and reduce the accumulation of zinc in the furnace; loosening the edge airflow and controlling the edge airflow not to be too strong to ensure the smooth operation of the blast furnace.

3. The method for treating blast furnace wall adhesion according to claim 1, characterized in that: The step S2 specifically includes: increasing the wind temperature to 1150-1250° C., reducing the height of the soft melting zone, increasing the proportion of blocky strip material columns, and discharging zinc through the coal gas flow; and increasing the oxygen enrichment rate to above 4.0%.

4. The method for treating blast furnace wall adhesion according to claim 1, characterized in that: In step S3, the increase in pressure difference meets the following prerequisites: the wind pressure is stable, the furnace charge drops normally, there is an upper limit value, and the increase range does not exceed 10% of the normal pressure difference.

5. The method for treating blast furnace wall adhesion according to claim 1, characterized in that: The step S4 specifically includes: utilizing the wind stop opportunity to reduce the tuyere, reducing the tuyere area by 8-12%, increasing the depth of the raceway, and reducing the dead material column in the center of the furnace; at the same time, in the process of restoring the furnace condition, the furnace temperature is controlled at a higher level of 1.0-1.5%, and the air inlet speed reaches more than 260m / s; under the action of the blast furnace temperature and high wind speed, the airflow violently scours the adhesive on the blast furnace wall, causing it to fall off quickly.

6. The method for treating blast furnace wall adhesion according to claim 1, characterized in that: The step S5 specifically includes: after processing the wall adhesion, continue to monitor the various parameters of the blast furnace and the temperature changes of the cooling wall. Once an abnormal situation is found, it should be adjusted and processed in time to maintain a reasonable furnace type. At the same time, it is also necessary to continuously optimize and improve the batching structure and operating parameters of the blast furnace to ensure that the slag basicity is around 1.20, and at the same time control the excessive pressure difference to return it to normal pressure difference.

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