Method for quickly reaching production capacity in blast furnace after repair

Abstract

The present application belongs to the technical field of blast furnace ironmaking, and particularly relates to a method for quickly reaching production capacity after blast furnace repair and blow-in, comprising the following contents: (1) optimizing the blast furnace repair and blow-in process, and prolonging the constant temperature blow-in time at 550 DEG C; (2) optimizing the blow-in charge composition; (3) charging with cold blast; (4) the blow-in process: 1. preparing for plugging the tuyere and blowing the iron notch; 2. quickly introducing coal gas; 3. controlling the parameters before the formation of the soft melting zone; 4. controlling the parameters after the formation of the soft melting zone; 5. adjusting the blast furnace coke ratio, coal ratio and rich oxygen during the blow-in process; 6. controlling the blast furnace molten iron [Si]; and 7. optimizing the charging matrix. The method combines the use of multiple technologies, such as prolonging the constant temperature blow-in time at 550 DEG C, charging with cold blast during the blow-in process, quickly introducing coal gas, reasonably controlling the parameters before and after the formation of the soft melting zone, gradually opening the tuyere, adjusting the blast furnace coke ratio, coal ratio and rich oxygen, and optimizing the charging matrix, to achieve the purposes of safe blow-in after blast furnace repair, improving production efficiency, reducing energy consumption, and quickly reaching production capacity.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace ironmaking technology, and particularly relates to a method for rapidly reaching production capacity during blast furnace repair and start-up. Background Technology

[0002] After many years of operation, a blast furnace needs to undergo intermediate or major repairs. The process of resuming normal production after an intermediate or major repair is called furnace restart. Traditionally, the constant temperature of 550℃ during blast furnace start-up and baking is 8-10 hours, which is too short. This results in insufficient heating of the refractory material in the blast furnace hearth and increased heat consumption during start-up. The static, non-ventilated charging process prevents the removal of powder generated during charging, reducing the permeability of the charge column and weakening its looseness. This hinders the rapid introduction of gas after blast furnace start-up, leading to prolonged gas introduction time, instability of furnace conditions, extended time to reach full production capacity, and high energy consumption. Furthermore, the single-ring charging matrix throughout the charging process causes an unreasonable gas flow distribution in the initial blast furnace start-up, making furnace conditions prone to fluctuations. The ratio of top pressure to hot blast pressure is controlled at 0.50-0.52 before and after the formation of the softening zone, but this is not adjusted in time. Additionally, the opening of the tuyeres during softening zone formation causes fluctuations in furnace conditions, resulting in a long start-up time to reach full production capacity, low efficiency, and high energy consumption. Summary of the Invention

[0003] The purpose of this invention is to provide a method for rapid production capacity during blast furnace repair and start-up, solving the problems of long start-up time, low efficiency, and high energy consumption.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for rapid production ramp-up during blast furnace repair and start-up includes the following:

[0006] (i) Optimize the blast furnace repair and drying process and extend the 550℃ constant temperature drying time.

[0007] The total oven drying time is 40-44 hours, with 2-3 hours for heating from 100℃ to 150℃, 6-7 hours for maintaining a constant temperature at 150℃, 4-5 hours for heating from 150℃ to 350℃, 4-6 hours for maintaining a constant temperature at 350℃, 4-5 hours for heating from 350℃ to 550℃, 15-18 hours for maintaining a constant temperature at 550℃, and 2-3 hours for cooling down; the initial air volume is 1170 m³ / h. 3 / min-1200m 3 / min, gradually increase the air volume to 1400m³ / min. 3 / min-1500m 3 / min;

[0008] (ii) Optimize the composition of the start-up feed

[0009] Prepare sufficient high-quality start-up feed: 100.00% top-charged coke, 360m 3 Two days before starting the furnace, all raw materials and fuels used, including sintered ore, pellets, manganese ore, silica, dolomite, limestone, and serpentine, should be fed into the silo and tested.

[0010] (iii) Loading with cold air

[0011] Low-temperature, oxygen-free cold air is supplied to the blast furnace through the hot blast stove's cold air gate and the mixing air regulating valve. During the cold air charging process, the air volume is controlled as follows: the air volume is 1.48-1.55 times the furnace volume per minute. When the charge reaches the furnace waist, the cold air pressure is 65 kPa-71 kPa. When the charge level is between the furnace waist and the middle of the furnace body, the cold air pressure is 72 kPa-75 kPa. When the charge level is above the middle of the furnace body, the cold air pressure is 75 kPa-90 kPa. During the charging process, the furnace top vent valve remains open, and the charging speed is controlled at 5-6 batches / h.

[0012] (iv) Furnace start-up process

[0013] 1. Preparation for blocking air vents and iron spraying nozzles

[0014] (1) Use a bowl filled with cement to block 4-6 air vents;

[0015] (2) Install ventilation pipes at the north and south iron outlets and prepare for the iron spraying nozzles;

[0016] 2. Rapidly introduce coal gas

[0017] After ignition and air supply, when the gas at the top of the furnace has O2 < 1%, H2 < 4%, and the top temperature is greater than 110℃ and less than 180℃, the conditions for igniting the gas are met. After the gas explosion test is successful, the gas is quickly ignited, that is, the gas is ignited within 1-2 hours of air supply.

[0018] 3. Controlling parameters before the formation of the remelted zone

[0019] The air volume is controlled at 1.48-1.55 times the furnace volume per minute for 6-7 hours, the air pressure is controlled at 140kpa-165kpa, and the ratio of top pressure to hot air pressure is controlled at 0.32-0.33.

[0020] 4. Controlling parameters after the formation of the remelted zone

[0021] The hot blast pressure was gradually increased from 160-165 kPa to 210-240 kPa, and the pressure difference (pressure difference = hot blast pressure - top pressure) was controlled at 110-130 kPa, maintaining a stable furnace condition. Then, the tuyeres were gradually and orderly opened. In the initial stage, the hot blast pressure increased by 13-15 kPa for each tuyer opened, controlled at 65%-75% of the normal tuyer air supply of 20 kPa. In the middle and later stages, the hot blast pressure increased by 16-18 kPa for each tuyer opened, controlled at 80%-90% of the normal tuyer air supply of 20 kPa. The ratio of top pressure to hot blast pressure was increased from 0.32-0.33 to 0.41, and then gradually restored to 0.55-0.57 to stabilize the airflow.

[0022] 5. Properly control the blast furnace coke ratio, coal ratio, and oxygen enrichment.

[0023] (1) The coke ratio in the blast furnace was gradually reduced from 600 kg / t to 375 kg / t;

[0024] (2) When the coke ratio in the blast furnace is 500 kg / t, pulverized coal injection begins, with a coal ratio of 15 kg / t-30 kg / t and an oxygen enrichment of 2000 m³ / t. 3 / h-2500m 3 / h;

[0025] 6. Controlling molten iron in the blast furnace [Si]

[0026] After the furnace is opened and oxygen-enriched with pulverized coal, the blast temperature is rapidly increased, causing the molten iron [Si] to drop rapidly to 0.90%-1.20%, and then steadily increase and stabilize at 0.45%-0.55%, with the physical heat of the molten iron reaching 1495℃-1515℃, ensuring sufficient physical heat of the molten iron.

[0027] 7. Optimize the cloth matrix

[0028] The material distribution method, which adopts central diversion and platform widening, forms a platform + funnel pattern, which improves gas utilization, stabilizes the central airflow, and enhances furnace stability.

[0029] Preferably, (a) further includes the blast furnace drying air pressure: the initial air pressure is 50 kPa-56 kPa, the air pressure is 57 kPa-60 kPa when the blast furnace is kept at a constant temperature of 150°C, the air pressure is 88 kPa-95 kPa when the blast furnace is kept at a constant temperature of 350°C, and the air pressure is 62 kPa-67 kPa when the blast furnace is kept at a constant temperature of 550°C.

[0030] Preferably, (iii) further includes a material line depth that is the same as the furnace throat height, a total coke ratio of 2820.0 kg / t, a slag-to-iron ratio of 896.2 kg / t, a magnesium-to-aluminum ratio of 0.57, and a slag basicity R2 of 0.83.

[0031] Preferably, the specific operation of optimizing the fabric matrix in step (iv) is as follows:

[0032] As the feed increases and the feed line rises, the coke feed gradually increases from a single ring of at least 12° to three rings, and the platform widens and moves outward. The ore feed maintains two rings, with the feed angle consistent with the innermost two rings of coke. The maximum feed angle of the ore is 2° smaller than that of the coke feed, and the platform moves outward synchronously with the coke platform. The coke is top-loaded, and the ore includes sinter, pellets, manganese ore, silica, dolomite, limestone, and serpentine.

[0033] Preferably, step 3 in (iv) further includes spraying and plugging the iron tap before the soft melt zone is formed.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0035] (1) Extend the time of constant temperature of 550℃ in the furnace to increase the heating range of the refractory material in the blast furnace hearth and reduce the heat consumption of the blast furnace opening;

[0036] (2) Using cold air charging, an upward airflow is generated from the tuyeres to blow out the dust and powder generated during the opening of the furnace and to improve the permeability of the charge column. The charge column is blown to keep it loose, which facilitates the rapid introduction of gas and the stabilization of the furnace condition after the blast furnace is ignited and blasted.

[0037] (3) In the early stage of furnace start-up, block the tuyeres before the soft melting zone is formed to maintain the wind speed and facilitate the stabilization of furnace conditions; quickly introduce coal gas to accelerate the heat transfer and reduction reaction in the furnace, improve the heat utilization rate of the hearth and the stability of the furnace conditions, and shorten the start-up and production time.

[0038] (4) Before and after the formation of the blast furnace softening zone, relevant parameters should be reasonably controlled. After the furnace condition is continuously stable after the formation of the blast furnace softening zone, the tuyeres should be opened gradually to stabilize the airflow, stabilize the furnace condition, reduce energy consumption, and improve efficiency.

[0039] (5) During the blast furnace start-up process, the coke ratio and coal ratio should be reasonably controlled to ensure sufficient heat in the hearth and stable smelting process. In addition, timely and appropriate oxygen enrichment should be used to improve the combustion efficiency of pulverized coal, increase the hearth temperature, and accelerate the smelting process, so as to avoid fluctuations in furnace conditions due to premature or excessive oxygen enrichment.

[0040] (6) The method of the present invention combines a variety of technologies, such as extending the blast furnace baking constant temperature of 550℃, adopting cold air charging during the furnace start-up process, rapidly introducing coal gas, reasonably controlling the parameters before and after the formation of the softening zone, gradually opening the tuyeres after the furnace condition has been continuously stable after the formation of the softening zone, adjusting the blast furnace coke ratio, adjusting the blast furnace coal ratio and oxygen enrichment, and optimizing the charging matrix, to achieve the purpose of safe blast furnace start-up during maintenance, improving production efficiency, reducing energy consumption, and rapidly reaching production capacity. Detailed Implementation

[0041] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0042] 5 #After the blast furnace undergoes a mid-term overhaul, the method for rapid production recovery upon restarting the blast furnace following the mid-term overhaul of this invention includes the following:

[0043] (a) Measure the dimensions of each part of the blast furnace to determine the charging volume.

[0044]

[0045] (ii) Blast furnace drying

[0046] 1. The oven baking started at 4:00 AM on January 21st. It took 2 hours to heat up from 100℃ to 150℃, 6 hours to maintain a constant temperature of 150℃, 4 hours to heat up from 150℃ to 350℃, 4 hours to maintain a constant temperature of 350℃, 4 hours to heat up from 350℃ to 550℃, 18 hours to maintain a constant temperature of 550℃, and 2 hours to cool down. The oven baking ended at 8:00 PM on January 22nd, for a total of 40 hours.

[0047] 2. Changes in air volume and air pressure: Initial air volume 1200m³ 3 The air volume was gradually increased to 1568 m³ / min when the blast furnace was kept at a constant temperature of 150℃. 3 / min, the blast volume at a constant temperature of 350℃ in the blast furnace is 1605m³ / min. 3 / min, the blast volume at a constant temperature of 550℃ in the blast furnace is 1461m³ / min. 3 / min; the initial blast pressure is 55 kPa, the blast pressure is 58 kPa when the blast furnace is kept at a constant temperature of 150℃, the blast pressure is 91 kPa when the blast furnace is kept at a constant temperature of 350℃, and the blast pressure is 65 kPa when the blast furnace is kept at a constant temperature of 550℃.

[0048] (III) Optimize the composition of the start-up feed

[0049] 100.00% top-loading coke, 360m 3 Sintered ore, pellets (Hongwei pellets), manganese ore, silica, dolomite, limestone, and serpentine. All raw materials and fuels used two days before furnace start-up were fed into the silo and tested. The composition of the start-up feed is shown in the table below:

[0050] Composition of sintered ore and pellets (Hongwei spheres)

[0051] ;

[0052] excipients

[0053] ;

[0054] Top-loading coke components

[0055] ;

[0056] Top-loading coke ash composition

[0057] .

[0058] (iv) Loading with cold air

[0059] 1. The distribution of the furnace charge at the start of operation is shown in the table below:

[0060] ;

[0061] 2. Composition of start-up feed

[0062] (1) Net coke weight per batch: 7100 kg / batch for top-loaded coke;

[0063] (2) Amount of empty coke per batch: (7100kg coke + 1450kg dolomite + 910kg silica + 1350kg limestone) / batch;

[0064] (3) Normal material composition:

[0065] Normal feed Z1 composition: (13500kg sinter + 1500kg sintered ore + 600kg manganese ore + 920kg silica + 460kg serpentine) / batch; 7100kg coke / batch; coke ratio 750.0kg / t; slag basicity R2=0.95;

[0066] Normal feed Z2 composition: (13500kg sinter + 1500kg Hongwei pellets + 600kg manganese ore + 1020kg silica + 310kg serpentine) / batch; 6050t coke / batch; coke ratio 650.0kg / t; slag basicity R2=0.95;

[0067] 3. Total furnace charge calculation: Charge line 1.65m (furnace throat height), total coke ratio 2820.0kg / t, slag-to-iron ratio 896.2kg / t, magnesium-to-aluminum ratio 0.57, slag basicity R2=0.83;

[0068] 4. The parameters for loading with cold air are controlled as follows:

[0069] ;

[0070] Loading with cold air began at 20:00 on January 22 and ended at 3:30 on January 23, totaling 7 hours and 30 minutes; the material line was 4.35 meters on the south foot and 3.50 meters on the north foot.

[0071] The cooling air volume is controlled at 1770m³. 3 / min-1860m 3 / min, based on a furnace volume of 1200m³ 3The cold air pressure is controlled at 1.48-1.55 times the normal pressure. When the charge level is below the furnace waist, the cold air pressure is 68kPa-71kPa; when the charge level is between the furnace waist and the middle of the furnace body, the cold air pressure is 72kPa-75kPa; when the charge level is above the middle of the furnace body, the cold air pressure is 77kPa-78kPa. The charging speed is controlled at 6 batches / h, and the furnace top vent valve is kept open during the charging process to ensure that the powder is blown out and the charge column is loosened.

[0072] (v) Furnace start-up process

[0073] 1. Preparation for blocking air vents and iron spraying nozzles

[0074] (1) 20 air vent sleeves: 10 Φ115mm (slanted) air vent sleeves and 10 Φ110mm air vent sleeves are used, with a total air inlet area of ​​0.1988m². 2 Before supplying air, use a bowl filled with cement to block six air vents: vents #2, #5, #8, #12, #15, and #18. The air supply area is 0.1453 m². 2 ;

[0075] (2) Install air ducts at the north and south iron outlets and prepare for the iron spraying process;

[0076] 2. Rapidly introduce coal gas

[0077] At 3:36 AM on January 23, the blast furnace was emptied, and the blast furnace parameters and gas analysis results are as follows:

[0078] Blast furnace parameter changes

[0079] ;

[0080] Blast furnace gas composition analysis

[0081] ;

[0082] The gas meets the requirements of O2 < 1% and H2 < 4%. After the blast furnace gas explosion test is successful and the top temperature is greater than 110℃ and less than 180℃, the conditions for igniting the gas are met. The gas is ignited quickly, and the blast furnace gas is ignited completely in 4:52, that is, the gas is ignited completely in 1 hour and 16 minutes after the air is supplied.

[0083] 3. Parameter control before the formation of the remelting band

[0084] At 9:00 AM on January 23, the taphole for slag injection in the north blast furnace was plugged. At 9:40 AM, the taphole for slag injection in the south blast furnace was plugged. The softening zone of the blast furnace was formed. The parameters before the softening zone was formed are as follows:

[0085] ;

[0086] Air volume maintained at 1769m 3 / min-1866m3 Between 4:52 and 4:52, after the blast furnace gas was introduced, the hot blast pressure was gradually increased from 74 kPa to 164 kPa. In order to stabilize the air volume, the ratio of top pressure to hot blast pressure was controlled at 0.32, and the top pressure was gradually increased from 5 kPa to 52 kPa to ensure the air velocity.

[0087] 4. Parameter control after the formation of the reconstituted zone

[0088] The parameters after the formation of the blast furnace softening zone are as follows:

[0089] ;

[0090] (1) Hot blast pressure adjustment: gradually increase from 164 kPa to 199 kPa, and then to 210 kPa. Hot blast is sent to 14 tuyeres when the blast furnace is started. The hot blast pressure corresponding to each tuyere is 15 kPa. The pressure difference is controlled at 110-130 kPa. The furnace condition is stable and the conditions for opening tuyeres are met. In the initial stage, the hot blast pressure is increased by 15 kPa for each tuyere opened, and controlled at 75% of the normal production air pressure of 20 kPa for each tuyere. In the middle and late stages, the hot blast pressure is increased by 17 kPa for each tuyere opened, and controlled at 85% of the normal production air pressure of 20 kPa for each tuyere. By 2:00 on January 24, the hot blast pressure was 346 kPa, reaching the full blast state (more than 85% of the normal air pressure is full blast).

[0091] (2) Top pressure adjustment: As the blast furnace increases air pressure, the top pressure increases from 52 kPa to 81 kPa, and then gradually increases to 188 kPa. The ratio of top pressure to hot blast pressure increases from 0.32 to 0.41, and then gradually returns to 0.55-0.57.

[0092] (3) At 14:02, the air vents were fully opened. The air vent opening process was as follows:

[0093] ;

[0094] 5. Adjust the coke ratio in the blast furnace and rationally control the coal ratio and oxygen enrichment.

[0095] After the blast furnace is blasted, the material is fed in. The coke ratio in the blast furnace is quickly adjusted from 650 kg / t to 600 kg / t, and then gradually and steadily reduced to 375 kg / t.

[0096] The blast furnace coke ratio was set at 500 kg / t to initiate pulverized coal injection, with a coal ratio of 22 kg / t and an oxygen enrichment of 2411 m³. 3 The parameter control settings for / h are as follows:

[0097] ;

[0098] 6. Controlling molten iron in the blast furnace [Si]

[0099] After oxygen-enriched pulverized coal injection at start-up, the blast temperature is rapidly increased, causing the [Si] content of the molten iron to drop quickly from 3.01% to between 0.90% and 1.20%, then steadily increase and stabilize between 0.45% and 0.55%. The physical heat of the molten iron reaches 1495-1515℃, ensuring sufficient physical heat. The changes in iron tapping and composition at the furnace are as follows:

[0100] ;

[0101] 7. Optimize the cloth matrix

[0102] A central airflow diversion and platform-widened material distribution method is adopted to form a platform + hopper pattern, which stabilizes the central airflow and enhances furnace stability. The adjustment of the coke and ore material distribution matrix is ​​shown in the table below:

[0103] Coke and ore material distribution matrix adjustment

[0104] ;

[0105] At 20:00 on January 22, the blast furnace began charging with cold air. As the charge increased, the charge line was raised. The coke charging line gradually increased from a single ring of at least 12° to three rings, while the ore charging line remained at two rings. The maximum angle of the ore charging line was 2.0° smaller than that of the coke charging line. The coke and ore platforms shifted outwards, and the charging matrix was adjusted as follows:

[0106] C 28.0 26.0 24..0 + O 26.0 24..0

[0107] 4 3 3 3 5

[0108] At 3:36 AM on January 23, the blast furnace was blasted, and the blast was gradually increased and the tuyeres were opened to gradually improve the furnace strength and ensure rapid recovery of furnace conditions. The coke and ore charging matrices were adjusted as follows:

[0109] C 39.0 37.0 34.5 32.0 29.0 + O 38.0 36.0 34.0 32.0

[0110] 3 3 2 2 2 2 3 3 2

[0111] The coke and ore platforms were simultaneously widened and moved outwards. The maximum angle of the coke feeding was increased from 28.0° to 39.0°, and the minimum angle from 24.0° to 29.0°. The difference between the maximum and minimum angles increased from 4.0° to 10.0°, and the number of feeding rings increased from 3 to 5, for a total of 12 feeding circles. The maximum angle of the ore feeding was increased from 26.0° to 38.0°, and the minimum angle from 24.0° to 32.0°. The difference between the maximum and minimum angles increased from 2.0° to 6.0°, and the number of feeding rings increased from 2 to 4, for a total of 10 feeding circles. The maximum angle of the ore feeding was 1.0° smaller than that of the coke feeding, and the minimum angle of the ore feeding was 3.0° larger than that of the coke feeding. The coke-ore feeding pattern was maintained, and two airflows were developed, which facilitated rapid recovery of furnace conditions.

[0112] With the continuous improvement of blast furnace strength, the coke and ore charging matrices were adjusted on January 24th.

[0113] C 40.0 38.0 35.5 33.0 30.0 + O 40..0 38.0 36.0 34.0

[0114] 3 3 2 2 2 2 3 3 2

[0115] To ensure continuous stability of furnace conditions, the coke and ore charging matrices were adjusted as follows on January 25:

[0116] C 40.5 38.5 36.0 33.5 29.5 + O 40.5 38.5 36.0 34.0

[0117] 3 3 2 2 2 2 3 3 2

[0118] The coke and ore platforms are simultaneously widened and moved outward. The maximum angle of the coke feeding is expanded to 40.5°, and the minimum angle is expanded to 29.5°, with the difference between the maximum and minimum angles increasing from 10.0° to 11.0°. The maximum angle of the ore feeding is expanded to 40.5°, the same as the maximum angle of the coke feeding, and the minimum angle is expanded to 34.0°, which is 4.5° larger than the minimum angle of the coke feeding. The difference between the maximum and minimum angles increases from 6.0° to 6.5°. The platform + hopper feeding mode is maintained, which moderately suppresses the edge airflow, strengthens the guidance of the central airflow, stabilizes the center, and enhances the stability of the furnace.

[0119] In this embodiment, the blast furnace gas was fully ignited in 1 hour and 16 minutes of blast ventilation, the softening zone was formed in 6 hours and 4 minutes of blast ventilation, iron was tapped in 8 hours and 44 minutes of blast ventilation, the tuyeres were fully open in 10 hours and 26 minutes of blast ventilation, and full blast was maintained in 22 hours and 24 minutes of blast ventilation. The blast furnace coal ratio gradually increased from 87.0 kg / t to 138.7 kg / t, and the fuel ratio gradually decreased from 567.3 kg / t to 516.0 kg / t. On the third day of blast ventilation, the daily output of the blast furnace reached 4258.40 tons, achieving safe and rapid start-up and production targets. The performance indicators are as follows:

[0120]

Claims

1. A method for rapid production ramp-up during blast furnace repair and start-up, characterized in that, Includes the following: (i) Optimize the blast furnace repair and drying process and extend the 550℃ constant temperature drying time. The total oven drying time is 40-44 hours, with 2-3 hours for heating from 100℃ to 150℃, 6-7 hours for maintaining a constant temperature at 150℃, 4-5 hours for heating from 150℃ to 350℃, 4-6 hours for maintaining a constant temperature at 350℃, 4-5 hours for heating from 350℃ to 550℃, 15-18 hours for maintaining a constant temperature at 550℃, and 2-3 hours for cooling down; the initial air volume is 1170 m³ / h. 3 / min-1200m 3 / min, gradually increase the air volume to 1400m³ / min. 3 / min-1500m 3 / min; (ii) Optimize the composition of the start-up feed Prepare sufficient high-quality start-up feed: 100.00% top-charged coke, 360m 3 Two days before starting the furnace, all raw materials and fuels used, including sintered ore, pellets, manganese ore, silica, dolomite, limestone, and serpentine, should be fed into the silo and tested. (iii) Loading with cold air Low-temperature, oxygen-free cold air is supplied to the blast furnace through the hot blast stove's cold air gate and the mixing air regulating valve. During the cold air charging process, the air volume is controlled as follows: the air volume is 1.48-1.55 times the furnace volume per minute. When the charge reaches the furnace waist, the cold air pressure is 65 kPa-71 kPa. When the charge level is between the furnace waist and the middle of the furnace body, the cold air pressure is 72 kPa-75 kPa. When the charge level is above the middle of the furnace body, the cold air pressure is 75 kPa-90 kPa. During the charging process, the furnace top vent valve remains open, and the charging speed is controlled at 5-6 batches / h. (iv) Furnace start-up process (1) Preparation for blocking air vents and iron spraying vents ① Use a bowl filled with cement to block 4-6 air vents; ② Install ventilation pipes at the north and south iron-producing areas and prepare the iron-spraying nozzles; (2) Rapidly introduce coal gas After ignition and air supply, when the gas at the top of the furnace has O2 < 1%, H2 < 4%, and the top temperature is greater than 110℃ and less than 180℃, the conditions for igniting the gas are met. After the gas explosion test is successful, the gas is quickly ignited, that is, the gas is ignited within 1-2 hours of air supply. (3) Controlling parameters before the formation of the remelting zone The air volume is controlled at 1.48-1.55 times the furnace volume per minute for 6-7 hours, the air pressure is controlled at 140kpa-165kpa, and the ratio of top pressure to hot air pressure is controlled at 0.32-0.

33. (4) Controlling parameters after the formation of the remelting zone The hot blast pressure was gradually increased from 160-165 kPa to 210-240 kPa, with the pressure difference controlled at 110-130 kPa. The pressure difference was calculated as hot blast pressure minus the top pressure. The furnace condition remained stable. Then, the tuyeres were opened gradually and systematically. Initially, the hot blast pressure increased by 13-15 kPa for each tuyer opened, controlled at 65%-75% of the normal tuyer increase of 20 kPa. In the middle and later stages, the hot blast pressure increased by 16-18 kPa for each tuyer opened, controlled at 80%-90% of the normal tuyer increase of 20 kPa. The ratio of top pressure to hot blast pressure was increased from 0.32-0.33 to 0.41, and then gradually returned to 0.55-0.

57. (5) Adjustment of blast furnace coke ratio, coal ratio and oxygen enrichment are reasonably controlled. ① The coke ratio in blast furnaces was gradually reduced from 600 kg / t to 375 kg / t; ② When the blast furnace coke ratio reaches 500 kg / t, pulverized coal injection begins, with a coal ratio of 15 kg / t-30 kg / t and an oxygen enrichment of 2000 mg / t. 3 / h-2500m 3 / h; (6) Controlling blast furnace molten iron [Si] After the furnace is opened and oxygen-enriched with pulverized coal, the blast temperature is rapidly increased, causing the molten iron [Si] to drop rapidly to 0.90%-1.20%, and then steadily increase and stabilize at 0.45%-0.55%, with the physical heat of the molten iron reaching 1495℃-1515℃, ensuring sufficient physical heat of the molten iron. (7) Optimize the fabric matrix By adopting a central flow diversion and platform widening method, a platform + funnel pattern is formed, which improves gas utilization and stabilizes the central airflow.

2. The method for rapid production ramp-up and start-up of a blast furnace during repair according to claim 1, characterized in that, The first part also includes the blast furnace drying air pressure: the initial air pressure is 50 kPa-56 kPa, the air pressure is 57 kPa-60 kPa when the blast furnace is kept at a constant temperature of 150°C, the air pressure is 88 kPa-95 kPa when the blast furnace is kept at a constant temperature of 350°C, and the air pressure is 62 kPa-67 kPa when the blast furnace is kept at a constant temperature of 550°C.

3. The method for rapid production ramp-up after blast furnace repair according to claim 1, characterized in that, The third part also includes the same material line depth as the furnace throat height, a total coke ratio of 2820.0 kg / t, a slag-to-iron ratio of 896.2 kg / t, a magnesium-to-aluminum ratio of 0.57, and a slag basicity R2 of 0.

83.

4. The method for rapid production ramp-up and start-up of a blast furnace during repair according to claim 1, characterized in that, The specific operation of optimizing the fabric matrix in (7) of (IV) is as follows: As the feed increases and the feed line rises, the coke feed gradually increases from a single ring of at least 12° to three rings, and the platform widens and moves outward. The ore feed maintains two rings, with the feed angle consistent with the innermost two rings of coke. The maximum feed angle of the ore is 2° smaller than that of the coke feed, and the platform moves outward synchronously with the coke platform. The coke is top-loaded, and the ore includes sinter, pellets, manganese ore, silica, dolomite, limestone, and serpentine.

5. The method for rapid production ramp-up and start-up of a blast furnace during repair according to claim 1, characterized in that, (3) in (iv) also includes spraying and plugging the iron tap before the soft melting zone is formed.

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