Method for adjusting tuyere area during blow-in period of blast furnace

Abstract

The invention belongs to the technical field of blast furnace smelting, and particularly discloses a blast furnace blow-in tuyere area adjusting method which comprises five steps of tuyere partition configuration at the initial blow-in stage, dynamic monitoring and parameter feedback, graded adjustment and optimization, abnormal working condition treatment and stable period transition. Through the five steps, the problems of coal gas flow unbalance, hearth inactivity and material suspension risk caused by a traditional fixed tuyere are solved, so that the liquid permeability index and the production efficiency are improved, and the material suspension rate is reduced by 80%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace smelting, in particular to a method for adjusting tuyere area during blast furnace start-up. BACKGROUND

[0002] Blast furnace start-up is a key stage in the smelting process, and its core challenge lies in insufficient heat state of the hearth, uneven distribution of gas flow, and poor permeability of the initial charge column. In traditional start-up operations, the tuyere area is usually fixed (such as a standard tuyere with a diameter of 110 mm), but there are the following technical defects: imbalance of blast kinetic energy: the fixed tuyere area cannot match the dynamic changes of the permeability of the initial charge column, resulting in fluctuations in blast kinetic energy (E) (such as <80 kJ / s or >120 kJ / s), excessive edge gas flow (edge / center gas flow ratio >1:0.6) or center accumulation; insufficient hearth activity: when the initial tuyere area is too large, the wind speed (<240 m / s) and penetration are insufficient, the dead column permeability index (Φ) <0.3, and the core temperature (PT) <1450℃; high risk of suspended material: when the pressure difference (ΔP) >180 kPa, the gas flow is easily disturbed, which can induce suspended material, and it takes more than 8 hours to recover, resulting in a loss of 15-20% of the daily average output. As shown in the example of A blast furnace start-up, the initial tuyere area of 0.3219 m 2 (diameter 110-120 mm) results in a blast kinetic energy of only 75-90 kJ / s, a wind speed of 240 m / s, and a hearth permeability index of 0.28-0.32, ultimately leading to a suspended material accident. Therefore, there is an urgent need for a tuyere area regulation method based on multi-parameter dynamic feedback to ensure smooth start-up. SUMMARY

[0003] The purpose of the present application is to provide a method for adjusting the tuyere area during the start-up of a blast furnace, which dynamically adjusts the tuyere area and the air volume ratio by monitoring the blast kinetic energy, the pressure difference, and the hearth permeability index in real time, and solves the problems of gas flow imbalance, hearth inactivity, and suspended material risk caused by traditional fixed tuyeres.

[0004] To achieve the above-mentioned purpose, the basic scheme provided by the present application is: a method for adjusting the tuyere area during the start-up of a blast furnace, comprising the following steps: S1: initial tuyere zoning configuration Divide the 30 tuyeres of the blast furnace into 4 control zones, each zone having 7-8 tuyeres, and set the initial tuyere diameter to 100-115 mm, corresponding to a total area of 0.2963 m 2 ; differentially configure the tuyere diameters in each zone; simultaneously set the initial air volume to 4300 Nm 3 / min, the target wind speed to 280 m / s, and the blast kinetic energy to 85-120 kJ / s; S2: dynamic monitoring and parameter feedback Real-time collection of ΔP, E, Φ, PT, edge / center airflow ratio, control threshold: E = 90-110 kJ / s, ΔP < 170 kPa, Φ > 0.35, edge / center airflow ratio 1:0.8; S3: hierarchical adjustment and optimization Stage I (0-24h): monitor the tuyere wind speed every 2h, if the wind speed deviation of a certain area is >10%, adjust the tuyere diameter of the area; when ΔP > 160 kPa, preferentially reduce the tuyere diameter of the edge area (1st area, 4th area) by 5mm; Stage II (24-72h): if Φ < 0.3, increase the tuyere diameter of the center area (2nd area, 3rd area) by 3mm, and simultaneously reduce the coal injection amount by 10kg / t; if PT < 1480℃, increase the wind temperature to 1150℃ and add 2 batches of clean coke; S4: abnormal condition handling Suspension material precursor (ΔP > 180 kPa): immediately reduce the air to 2500Nm / min, and reduce the top pressure to 50 kPa; replace the water leakage tuyere small sleeve and adjust the tuyere area of the corresponding area; add 3 batches of clean coke, and reduce the load by 0.3. 3

[0005] Further, the increased clean coke in step S4 is 15t per batch.

[0006] Further, it further comprises step S5: transition in stable period, specifically: when ηCO > 45%, ΔP < 150 kPa for 4h, gradually expand all tuyeres to the standard diameter of 110mm.

[0007] Further, in step S1, the tuyere diameters of 3#, 10#, 12#, 18# and 27# are set to 100mm.

[0008] Further, in step S3, the tuyere adjustment needs to be monitored simultaneously to ensure that the dead material column porosity is >25%.

[0009] Further, in step S4, the coal injection amount needs to be maintained at ≤80kg / t after the suspension material treatment.

[0010] Compared with the prior art, the advantages of the present application are: 1. Gas flow optimization: the edge / center airflow ratio is optimized from 1:0.6 to 1:0.8, ηCO is increased to 45%; furnace hearth activation: the liquid permeability index is increased from 0.28 to 0.38, and PT is stable >1480℃; production efficiency: the suspension rate is reduced by 80%, and the production time is shortened to 72h. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structure diagram of tuyere partition configuration in the method of adjusting tuyere area during the blowing-in period of the blast furnace.​ DETAILED DESCRIPTION

[0012] The application will be further described in detail by the specific embodiments: As Figure 1 shown: a method for adjusting tuyere area during the start-up of a blast furnace, comprising the following steps: S1: tuyere zoning configuration in the early stage of start-up Divide the 30 tuyeres of the blast furnace into 4 control zones, with 7-8 tuyeres in each zone, and set the initial tuyere diameter to 100-115 mm, corresponding to a total area of 0.2963 m 2 ; Differentiate the tuyere diameters in each zone, and preferentially set the diameters of tuyeres 3#, 10#, 12#, 18#, and 27# to 100 mm; simultaneously set the initial air volume to 4300 Nm 3 / min, the target air speed to 280 m / s, and the blast kinetic energy to 85-120 kJ / s; S2: dynamic monitoring and parameter feedback Real-time collection of ΔP, E, Φ, PT, and edge / center airflow ratio, with control thresholds of E = 90-110 kJ / s, ΔP < 170 kPa, Φ > 0.35, and edge / center airflow ratio 1:0.8; S3: staged adjustment and optimization Stage I (0-24 h of start-up): monitor the tuyere speed every 2 h, and if the speed deviation of a zone is >10%, adjust the tuyere diameter of that zone; when ΔP > 160 kPa, preferentially reduce the tuyere diameter of the edge zone (zones 1 and 4) by 5 mm; Stage II (24-72 h): if Φ < 0.3, increase the tuyere diameter of the center zone (zones 2 and 3) by 3 mm, and simultaneously reduce the coal injection amount by 10 kg / t; if PT < 1480℃, increase the blast temperature to 1150℃ and add 2 batches of clean coke; simultaneously monitor the dead manhole porosity to ensure that the dead manhole porosity is >25%; S4: abnormal condition handling Suspension material precursor (ΔP > 180 kPa): immediately reduce the air volume to 2500 Nm 3 / min, and the top pressure to 50 kPa; shut down to replace the water leakage tuyere small sleeve, adjust the tuyere area of the corresponding zone; add 3 batches of clean coke, each batch being 15 t, reduce the load ratio by 0.3, and after handling the suspension material, maintain the coal injection amount ≤80 kg / t.

[0013] Step S5: transition in the stable period, specifically: when ηCO > 45% and ΔP < 150 kPa for 4 h, gradually expand all tuyeres to the standard diameter of 110 mm.

[0014] The implementation of the above method in the blast furnace of Bayi Steel is as follows: Initial configuration: Air outlet diameter set according to 4 zones, total area 0.2963m² 2 Air volume 4300Nm 3 / min, air temperature 1050℃, coke ratio 3.5t / t; Phase I (0-24h): Monitoring revealed that the wind speed in Zone 1 was low (260m / s). The diameter of the No. 9 and No. 15 air outlets was reduced from 115mm to 110mm. After the adjustment, the wind speed increased to 275m / s, and ΔP decreased from 170kPa to 165kPa. Phase II (24-48h): When Φ=0.29, the No. 5 tuyere in Zone 2 is expanded from 115mm to 118mm, the coal injection rate is reduced from 80kg / t to 70kg / t, PT is increased from 1460℃ to 1490℃, and Φ is improved to 0.36.

[0015] Abnormal Handling: When ΔP=185kPa, handle according to S4 plan, and restore the air volume to 4200Nm after 6 hours. 3 / min.

[0016] Treatment of stubborn suspended materials Accident background: After the material is suspended, the material line is 9.4m long with a diameter of 0.25mm. The small sleeve of the No. 13 air outlet is leaking water. Handling procedure: Replace unit #13 and adjust the vent area of ​​its corresponding zone 3 to 0.0693m². 2 Add 2 tons of fluorite per batch for furnace cleaning, increasing the coke ratio to 3.8 tons per ton. Recovery effect: After 48 hours, Φ=0.38, ηCO=44%, and air volume stabilized at 4500Nm. 3 / min.

[0017] 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 adjusting the tuyeres area during blast furnace start-up, characterized in that, Includes the following steps: S1: Initial Furnace Start-up Tubular Zone Configuration The 30 tuyeres in the blast furnace were divided into 4 control zones, with 7-8 tuyeres in each zone. The initial tuyere diameter was set at 100-115 mm, corresponding to a total area of ​​0.2963 m². 2 Differentiated configuration of air outlet diameters for each zone; Initial airflow set synchronously to 4300 Nm. 3 / min, target wind speed 280m / s, blower kinetic energy 85-120kJ / s; S2: Dynamic Monitoring and Parameter Feedback Real-time acquisition of ΔP, E, Φ, PT, and edge / center airflow ratio; control thresholds: E=90-110kJ / s, ΔP<170kPa, Φ>0.35, edge / center airflow ratio 1:0.8; S3: Hierarchical Adjustment and Optimization Phase I (0-24h after furnace start-up): Monitor the tuyere wind speed every 2 hours. If the wind speed deviation in a certain area is >10%, adjust the tuyere diameter in that area. When ΔP >160kPa, prioritize reducing the tuyere diameter in the edge areas (zones 1 and 4) by 5mm. Phase II (24-72h): If Φ < 0.3, increase the diameter of the tuyeres in the central area (zones 2 and 3) by 3mm and simultaneously reduce the coal injection rate by 10kg / t; if PT < 1480℃, increase the air temperature to 1150℃ and add 2 batches of clean coke. S4: Abnormal Operating Condition Handling Predictive sign of material suspension (ΔP > 180 kPa): Immediately reduce airflow to 2500 Nm 3 / min, top pressure dropped to 50kPa; shut down the ventilation and replaced the leaking air vent sleeve, and adjusted the air vent area of ​​the corresponding area; added 3 batches of clean coke, and the load ratio decreased by 0.

3.

2. The method for adjusting the tuyeres area during blast furnace start-up according to claim 1, characterized in that, The amount of net coke added in step S4 is 15t per batch.

3. The method for adjusting the tuyeres area during blast furnace start-up according to claim 1, characterized in that, It also includes step S5: stabilization transition, which is: after ηCO > 45% and ΔP < 150kPa for 4 hours, gradually expand all air outlets to a standard diameter of 110mm.

4. The method for adjusting the tuyeres area during blast furnace start-up according to claim 1, characterized in that, In step S1, the diameter of air outlets #3, #10, #12, #18, and #27 is preferentially set to 100mm.

5. The method for adjusting the tuyeres area during blast furnace start-up according to claim 1, characterized in that, When adjusting the air outlet in step S3, the porosity of the dead material column must be monitored simultaneously to ensure that the porosity of the dead material column is greater than 25%.

6. The method for adjusting the tuyeres area during blast furnace start-up according to claim 1, characterized in that, In step S4, the pulverized coal injection rate must be maintained at ≤80kg / t after the suspension treatment.

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