Method for treating suspended materials in blast furnace

Abstract

The invention belongs to the technical field of blast furnace smelting, and particularly discloses a method for treating suspended materials in a blast furnace, which specifically comprises the following steps of: dividing the suspended materials into general suspended materials, serious suspended materials and intractable suspended materials according to pressure difference, through burning index (K value) and stockline depth; then, multi-parameter linkage regulation and control are achieved by establishing a time sequence operation rule of air volume, top pressure, feeding and thermal compensation; and finally, the coal injection ratio is optimized in combination with the liquid permeability index of the dead stock column and the coal gas utilization rate (eta CO), and the technical blind area in suspended material treatment is solved through a graded response mechanism and dynamic parameter closed-loop control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace smelting, in particular to a method for treating suspended material in a blast furnace. BACKGROUND

[0002] Suspended material is a typical malignant accident in the process of blast furnace smelting, which is manifested as the stagnation of furnace charge, the sudden rise of pressure difference and the deterioration of gas permeability. According to the suspended material in the process of starting up the A blast furnace of Bayi Steel, the causes of suspended material are complex, including: imbalance of heat system: insufficient heat accumulation in the hearth (PT<1470℃, Si<0.3%), and too high fuel ratio (>600kg / t); disordered gas distribution: unreasonable tuyere configuration (blowing kinetic energy <90kJ / s), and too vigorous edge gas flow (edge / center gas flow ratio >1:0.6); lagging operation response: wind is not reduced in time when the pressure difference is >180kPa, and the wind is increased and the top pressure is raised simultaneously; structural defects of the hearth: dead column liquid permeability index <0.3, and coke pulverization rate >30%.

[0003] The traditional suspended material treatment method has the following defects: only relying on single wind reduction operation, ignoring the synergy of wind volume-top pressure-charge; not responding to the severity of suspended material, resulting in insufficient treatment or over-treatment; lacking dynamic regulation of the thermal state of the hearth and the utilization rate of gas. SUMMARY

[0004] The purpose of the present application is to provide a method for treating suspended material in a blast furnace to solve the problems of insufficient treatment or over-treatment in the prior art.

[0005] To achieve the above-mentioned purpose, the basic scheme provided by the present application is: a method for treating suspended material in a blast furnace, comprising: S1: suspended material classification diagnosis general suspended material: pressure difference 160-180kPa, K value 5.0-5.5, and material line fluctuation <2m; severe suspended material: pressure difference >180kPa, K value >5.5, and material line sudden drop 3-5m, which needs to be forced to settle material; stubborn suspended material: the material does not fall within 30 minutes after settling, accompanied by ηCO<40%, and dead column porosity <25%; S2: classification response treatment 1) general suspended material treatment reduce the wind to 70% of the current wind volume; the top pressure is lowered by 0.02kPa simultaneously according to the wind volume; add one batch of clean coke, and reduce the load ratio by 0.1; 2) severe suspended material treatment initial stage: wind volume is suddenly reduced to 600m 3 / min, furnace top pressure shut off to 50kPa; Material handling procedure: Add 3 batches of clean coke, reduce the load ratio by 0.3, and increase the coke layer thickness by 450mm; Recovery phase: Air volume reduced from 2500m³ / h 3 Start at / min, increase by 50m every 10 minutes. 3 / min; the furnace top pressure is adjusted with a lag of air volume × 0.018 kPa; when ηCO > 45% and K value < 5.0, the ore load is gradually increased; Treatment of stubborn suspended materials Thermal compensation: If the Si content of molten iron is <0.3%, the air temperature is increased to 1130℃; if the Si content of molten iron is >0.8%, the coal injection rate is reduced by 10kg / t. Air vent intervention: Stop the airflow, replace the leaking manhole cover, and adjust the air vent area to 0.2963m². 2 ; Dead material column activation: If the K value is <0.3, fluorite is added to wash the furnace, and the coke ratio is increased to 3.5t / t; S3: Dynamic monitoring and closed-loop control Parameter monitoring: Differential pressure, K value, ηCO, PT, and [Si] are collected every 5 minutes; Automatic triggering: When the pressure difference is greater than 170 kPa and the K value is greater than 5.0, the central control platform will issue an early warning and initiate the air reduction program; Recovery criteria: K value ≤ 4.5, ηCO > 47%, PT > 1480℃ must be met simultaneously.

[0006] Furthermore, in step S2, the amount of net coke added during the general suspension process is 5t per batch.

[0007] Furthermore, in step S2, the K value needs to be monitored during the suspension process. If the K value is ≤5.0 within 30 minutes, then proceed with a 50m... 3 / min stepped air supply.

[0008] Furthermore, the amount of net coke added per batch during the severe suspension treatment in step S2 is 15t.

[0009] Furthermore, in step S2, the ore load added each time during the severe suspension treatment is 0.05.

[0010] Furthermore, it also includes step S4: preventative maintenance, as follows: Charging system: The angle difference between ore and coke distribution is ≥7°; Air outlet configuration: blower kinetic energy ≥100kJ / s, wind speed >280m / s; Heat reserve management: During the start-up phase, the amount of sleepers filled should be ≥300m³. 3 Oven baking time > 120 hours.

[0011] Furthermore, the weighted angle of the coke fabric is 37°, and the weighted angle of the ore fabric is 30°.

[0012] Compared with the prior art, the advantages of this invention are: 1. Graded and precise response: Differentiated processes are matched according to the type of suspended material, improving processing efficiency by 50%; Dynamic closed-loop control: Human error is avoided by adjusting ηCO and K value in a coordinated manner; Long-term maintenance of the hearth: The permeability index of the dead material column is improved by 30%, extending the blast furnace life. Detailed Implementation

[0013] The present invention will be further described in detail below through specific embodiments: A method for handling suspended materials in a blast furnace includes: S1: Suspension material grading diagnosis Typical suspended material: pressure difference 160-180kPa, K value 5.0-5.5, material line fluctuation <2m; Severe material suspension: pressure difference > 180 kPa, K value > 5.5, material drop of 3-5m, forced material setting required; Stubborn suspended charge: The furnace charge does not fall within 30 minutes after being set, accompanied by ηCO < 40% and dead charge column porosity < 25%; S2: Hierarchical Response Processing 1) General suspension material treatment Reduce the air volume to 70% of the current air volume; simultaneously reduce the furnace top pressure by 0.02 kPa based on the air volume; add one batch of clean coke, 5 tons per batch, reducing the load ratio by 0.1; monitor the K value, and if the K value is ≤5.0 within 30 minutes, adjust the pressure by 50m... 3 / min stepped air supply; 2) Severely suspended material treatment Initial stage: Air volume drops sharply to 600m 3 / min, furnace top pressure shut off to 50kPa; Material handling procedure: Add 3 batches of clean coke, each batch being 15t, reduce the load ratio by 0.3, and increase the coke layer thickness by 450mm; Recovery phase: Air volume reduced from 2500m³ / h 3 Start at / min, increase by 50m every 10 minutes. 3 / min; the furnace top pressure is adjusted with a lag of air volume × 0.018 kPa; when ηCO > 45% and K value < 5.0, the ore load is gradually increased, with each increase being 0.05; Treatment of stubborn suspended materials Thermal compensation: If the Si content of molten iron is <0.3%, the air temperature is increased to 1130℃; if the Si content of molten iron is >0.8%, the coal injection rate is reduced by 10kg / t. Air vent intervention: Stop the airflow, replace the leaking manhole cover, and adjust the air vent area to 0.2963m². 2 ; Dead material column activation: If the K value is <0.3, fluorite is added to wash the furnace, and the coke ratio is increased to 3.5t / t; S3: Dynamic monitoring and closed-loop control Parameter monitoring: Differential pressure, K value, ηCO, PT, and [Si] are collected every 5 minutes; Automatic triggering: When the pressure difference is greater than 170 kPa and the K value is greater than 5.0, the central control platform will issue an early warning and initiate the air reduction program; Recovery criteria: K value ≤ 4.5, ηCO > 47%, PT > 1480℃ must be met simultaneously.

[0014] Step S4: Preventive Maintenance Charging system: The angle difference between ore and coke is ≥7°, the weighted angle of coke is 37°, and the weighted angle of ore is 30°. Air outlet configuration: blower kinetic energy ≥100kJ / s, wind speed >280m / s; Heat reserve management: During the start-up phase, the amount of sleepers filled should be ≥300m³. 3 Oven baking time > 120 hours.

[0015] The above method is used in the following example to handle suspended materials during the start-up of the blast furnace at Baosteel: Example 1: Treatment of Severely Suspended Materials Accident background: The pressure difference is 188 kPa, the K value is 5.8, and the material line drops sharply from 5.2 m to 9.4 m; the molten iron PT=1367℃, [Si]=0.97%, and ηCO=38%.

[0016] Processing procedure: 1) Initial airflow reduction: Within 3 minutes, the airflow decreases from 4200 m³ / h. 3 / min decreased to 600m 3 / min, furnace top pressure shut off to 50kPa; 2) Material setting operation: Add 3 batches (15t) of clean coke, and the load ratio is reduced from 3.44 to 3.14; 3) Airflow recovery: at 2500m 3 Starting from / min (8m material line), add 50m every 10 minutes. 3 / min; air volume up to 3200m 3 When the pressure reaches 60 kPa / min, the furnace top pressure is increased to 60 kPa (3200 × 0.018 ≈ 58 kPa, rounded down); when the K value drops to 5.0, the air volume is increased to 3800 m³ / min. 3 / min, top pressure synchronized to 70kPa.

[0017] 4) Thermal regime adjustment: Air temperature increased from 1050℃ to 1100℃, [Si] restored to 1.2%; 5) Hearth repair: Coal injection rate was reduced from 80 kg / t to 60 kg / t, and dead material column porosity was increased from 24% to 28%.

[0018] Recovery results: After 6 hours, the K value stabilized at 4.8, ηCO = 44%, and PT = 1490℃; within 24 hours, the load recovered to 3.2, and the air volume reached 4500m³. 3 / min.

[0019] Example 2: Treatment of Stubborn Suspended Materials Accident background: After the charge was placed, the furnace charge remained undisturbed for 40 minutes, with a liquid permeability index of 0.26; water leaked from the tuyeres #13 and #29, and the blast energy was only 75 kJ / s.

[0020] Processing procedure: 1) Intervention for ventilation shutdown: Replace the leaking sleeve and adjust the vent area to 0.2963m². 2 (Diameter 100-115mm); 2) Furnace cleaning operation: Add 2t / batch of fluorite, increasing the coke ratio to 3.5t / t; 3) Optimization of coal gas flow: The wind speed was increased to 280m / s, and the edge / center airflow ratio was optimized from 1:0.6 to 1:0.8.

[0021] Recovery effect: The permeability index of the dead material column increased to 0.35, and ηCO increased from 40% to 45%; the air volume stabilized at 4300 m³ / h within 48 hours. 3 / min, no secondary suspension of material.

[0022] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for treating suspended materials in a blast furnace, characterized in that, include: S1: Suspension material grading diagnosis Typical suspended material: pressure difference 160-180kPa, K value 5.0-5.5, material line fluctuation <2m; Severe material suspension: pressure difference > 180 kPa, K value > 5.5, material drop of 3-5m, forced material setting required; Stubborn suspended charge: The furnace charge does not fall within 30 minutes after being set, accompanied by ηCO < 40% and dead charge column porosity < 25%; S2: Hierarchical Response Processing 1) General suspension material treatment Reduce the air volume to 70% of the current air volume; adjust the furnace top pressure by 0.02 kPa based on the air volume; add one batch of clean coke, and reduce the load ratio by 0.1; 2) Severely suspended material treatment Initial stage: Air volume drops sharply to 600m 3 / min, furnace top pressure shut off to 50kPa; Material handling procedure: Add 3 batches of clean coke, reduce the load ratio by 0.3, and increase the coke layer thickness by 450mm; Recovery phase: Air volume reduced from 2500m³ / h 3 Start at / min, increase by 50m every 10 minutes. 3 / min; the furnace top pressure is adjusted with a lag of air volume × 0.018 kPa; when ηCO > 45% and K value < 5.0, the ore load is gradually increased; Treatment of stubborn suspended materials Thermal compensation: If the Si content of molten iron is <0.3%, the air temperature is increased to 1130℃; if the Si content of molten iron is >0.8%, the coal injection rate is reduced by 10kg / t. Air vent intervention: Stop the airflow, replace the leaking manhole cover, and adjust the air vent area to 0.2963m². 2 ; Dead material column activation: If the K value is <0.3, fluorite is added to wash the furnace, and the coke ratio is increased to 3.5t / t; S3: Dynamic monitoring and closed-loop control Parameter monitoring: Differential pressure, K value, ηCO, PT, and [Si] are collected every 5 minutes; Automatic triggering: When the pressure difference is greater than 170 kPa and the K value is greater than 5.0, the central control platform will issue an early warning and initiate the air reduction program; Recovery criteria: K value ≤ 4.5, ηCO > 47%, PT > 1480℃ must be met simultaneously.

2. The method for treating suspended materials in a blast furnace according to claim 1, characterized in that, In step S2, the amount of net coke added during the general suspension process is 5 tons per batch.

3. The method for treating suspended materials in a blast furnace according to claim 1, characterized in that, In step S2, the K value needs to be monitored during the suspension process. If the K value is ≤5.0 within 30 minutes, then proceed with a 50m... 3 / min stepped air supply.

4. The method for treating suspended materials in a blast furnace according to claim 1, characterized in that, The amount of net coke added per batch during the severe suspension treatment in step S2 is 15t.

5. A method for treating suspended materials in a blast furnace according to claim 1, characterized in that, In step S2, the ore load added each time during the severe suspension treatment is 0.

05.

6. A method for treating suspended materials in a blast furnace according to claim 1, characterized in that, It also includes step S4: preventative maintenance, as follows: Charging system: The angle difference between ore and coke distribution is ≥7°; Air outlet configuration: blower kinetic energy ≥100kJ / s, wind speed >280m / s; Heat reserve management: During the start-up phase, the amount of sleepers filled should be ≥300m³. 3 Oven baking time > 120 hours.

7. A method for treating suspended materials in a blast furnace according to claim 6, characterized in that, The weighted angle of the coke fabric is 37°, and the weighted angle of the ore fabric is 30°.