Rapid reblowing method for long-term damping down of blast furnace

Abstract

The invention relates to a quick reblowing method for long-term damping down of a blast furnace, which belongs to the technical field of blast furnace ironmaking and comprises the damping down process: S1, adding coke in one tank, and replacing sintering with 5 tons of manganese ore; the coke adding retreating load is 4.21, the ore batch is 42 tons, and the coke batch is 9.98 tons; s2, adding coke into three tanks, and replacing sintering with 15 tons of manganese ore; after coke is added, the ore batch reaches 40 tons, the load reaches 4.01, and the coke batch reaches 9.98 tons; s3, adding coke into two tanks, and replacing sintering with 10 tons of manganese ore; the ore batch is 40 tons, the load is 4.01, and the coke batch is 9.98 tons; and S4, one tank of coke is added again, 5 tons of manganese ore is used for replacing sintering, the ore batch is 40 tons, the load reaches 4.01, and the coke batch is 9.98 tons. Re-blowing operation: adding 1-2 tanks of coke when the furnace top has a discharging condition; four air ports are blocked before air supply; air is sent to an exhaust valve 5 minutes ahead of time; when the air pressure is greater than 50kPa, the air supply condition of more than eight spray guns is met, compressed air is supplied, and the hydraulic coal cutting guns are seen; in the early stage of air supply, air is added to 300 kPa by several times; and after the materials are moved, blowing and oxygen enrichment are recovered, the ore batch is expanded, the load is added, and the stock line is supplemented. According to the method, the whole wind recovery time is shortened to 35% of the original time.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and relates to a method for quickly resuming the ventilation of a blast furnace after a long-term shutdown, and in particular to a method for quickly resuming the ventilation of a blast furnace after a long-term shutdown (more than 20 hours). Background Art

[0002] As the core equipment of the long-process ironmaking, the operating efficiency and stability of the blast furnace directly affect the output and quality of steel production. As a continuous reactor, the blast furnace generally has a long-term wind-down maintenance (more than 20 hours) within half a year, or due to the increase in production uncertainties such as environmental protection restrictions and safety inspections, the long-term wind-down of the blast furnace is increasing. After a long wind-down, the re-blowing operation of the blast furnace is a technically difficult task. In order to ensure that the blast furnace can resume production quickly and stably, a series of technical measures need to be taken. These measures include preparations before the wind-down, the addition of wind-down materials, the adjustment of parameters such as air volume, wind temperature, furnace temperature, etc. during the re-blowing operation, and the optimization of the charge structure and slag-making system.

[0003] Although the technology of long-term wind-off and wind-reopening of blast furnaces has made some progress, there are still some problems. Among them, the time it takes for the blast furnace to reach full wind after the wind is supplied is generally half of the wind-off time, which will cause great production losses and cost losses. This is a problem that needs to be solved at present. Summary of the invention

[0004] The present invention aims to provide a method for quickly restoring the blast furnace after long-term wind stoppage, which shortens the time for restoring full wind to 35% of the original time and greatly reduces the cost.

[0005] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0006] A method for quickly restoring the blast furnace after a long-term shutdown, comprising the following operations:

[0007] Rest process:

[0008] S1. Add one can of coke (a batch of 8.7 tons of coke), 5 tons of manganese ore instead of sintering; after adding coke, the load is reduced to 4.21, the ore batch is 42 tons, sintered ore 63% + pellet ore 25% + lump ore 12%, and the coke batch is 9.98 tons;

[0009] S2. Add 3 cans of coke and 15 tons of manganese ore instead of sintering. According to volume calculation, the first can of coke reaches the upper part of the furnace waist; after adding coke, 40 tons of ore batches are withdrawn, the load is 4.01, sintering 62% + pellet 26% + lump 12%, coke batch 9.98 tons, 10 batches are taken;

[0010] S3. Add 2 more coke tanks, 10 tons of manganese ore instead of sintering; 40 tons of ore batch, load to 4.01, sintering 62% + pellet 26% + lump 12%, coke batch 9.98 tons;

[0011] S4. Add another can of coke, 5 tons of manganese ore instead of sintering, 40 tons of ore batch, load to 4.01, sintering 62% + pellet 26% + lump 12%, coke batch 9.98 tons;

[0012] Rewind operation:

[0013] After the furnace wall is treated, wait until the furnace top is ready for discharge and add 1-2 cans of coke (9.98 tons);

[0014] Before supplying air, block the four air vents (no single air supply vent can be sandwiched between the blocked vents to prevent leakage), and block them firmly with bricks so that they cannot be opened without poking;

[0015] Before supplying air, check with the trough, fan room, pump room, and slag flushing room to confirm everything. Supply air only after confirmation.

[0016] The foreman sent the air to the exhaust valve 5 minutes in advance according to the maintenance progress in front of the furnace;

[0017] When the wind pressure is greater than 50kPa, the conditions for more than 8 spray guns to supply air are met, and the coal spraying workers are notified to supply compressed air (coal spraying carrier) and the hydraulic workers are required to start the spraying;

[0018] In the early stage of air supply, add air several times to 300kPa;

[0019] After the material starts moving, coal injection and oxygen enrichment are resumed, and the ore batch is expanded and the load is increased. The ore batch is 40 tons, the coke batch is 9 tons, the load is 4.44, and the material line is completed.

[0020] Furthermore, the cloth angle and cloth turns are controlled as follows during air supply:

[0021] The material line is 1.4m, the angle and number of circles of the mine platform are 33°2 circles, 31.3°3 circles, 29.3°3 circles, 27°2 circles, 24.3°2 circles; the angle and number of circles of the coking platform are 35.3°3 circles, 33.1°3 circles, 30.3°2 circles, 27.3°2 circles, 23.8°1 circle, 13°3 circles;

[0022] The material line is 1.4-1.8m, the angle and number of circles of the mine platform are 32°2 circles, 30.3°3 circles, 28.3°3 circles, 26°2 circles, 23.3°2 circles; the angle and number of circles of the coking platform are 34.3°3 circles, 32.1°3 circles, 29.3°2 circles, 26.3°2 circles, 22.8°1 circle, 13°3 circles;

[0023] The material line is 1.8-2.2m, the angle and number of circles of the mine platform are 31°2 circles, 29.3°3 circles, 27.3°3 circles, 25°2 circles, 22.3°2 circles; the angle and number of circles of the coking platform are 33.3°3 circles, 31.1°3 circles, 28.3°2 circles, 25.3°2 circles, 21.8°1 circle, 13°3 circles;

[0024] The material line is 2.2-2.6m, the angle and number of circles of the mine platform are 30°2 circles, 28.3°3 circles, 26.3°3 circles, 24°2 circles, 21.3°2 circles; the angle and number of circles of the coking platform are 32.3°3 circles, 30.1°3 circles, 27.3°2 circles, 24.3°2 circles, 20.8°1 circle, 13°3 circles;

[0025] The material line is 2.6-3.3m, the angle and number of circles of the mine platform are 29°2 circles, 27.3°3 circles, 25.3°3 circles, 23°2 circles, 20.3°2 circles; the angle and number of circles of the coking platform are 31.3°3 circles, 29.1°3 circles, 26.3°2 circles, 23.3°2 circles, 19.8°1 circle, 13°3 circles;

[0026] The material line is 3.3-4.0m, the angle and number of circles of the mine platform are 28°2 circles, 26°3 circles, 23°2 circles, and 20°2 circles; the angle and number of circles of the coking platform are 30.5°3 circles, 28.5°3 circles, 26°2 circles, 23°2 circles, 19.5°1 circle, and 13°3 circles;

[0027] The material line is 4.0-5.0m, the angle and number of circles of the mine platform are 26.5°2 circles, 24.5°3 circles, 21°3 circles, 18°2 circles; the angle and number of circles of the coking platform are 29°3 circles, 27°3 circles, 24.5°2 circles, 21°2 circles, 18°1 circle, 13°3 circles;

[0028] The material line is 5.0-6.0m, the angle and number of circles of the mine platform are 25°2 circles, 23°3 circles, 20°3 circles, 17°2 circles; the angle and number of circles of the coking platform are 27°3 circles, 25°3 circles, 22°2 circles, 19°2 circles, 16°1 circle, 13°3 circles;

[0029] The material line is 6.0-7.0m. The feeding angle and number of feeding circles of the mining platform are 23°2 circles, 20°3 circles, and 16.5°2 circles; the feeding angle and number of feeding circles of the coking platform are 25°3 circles, 23°3 circles, 20°2 circles, 17°2 circles, 23.8°1 circle, and 13°3 circles.

[0030] Furthermore, the time interval between step S1 and step S2 is 3.5 hours, the time interval between step S2 and step S3 is 100 minutes, and the time interval between step S3 and step S4 is 90 minutes.

[0031] Furthermore, the silicon content in the molten iron is controlled to be above 0.45% before the wind is stopped.

[0032] Furthermore, after air supply, if the material line depth exceeds 4 meters, the coke ring belt will be collected. The material line within 4 meters has a 1-meter material line and a 2° angle to collect the coke. For material lines above 5 meters, multi-ring material distribution becomes meaningless, and the coke ring belt should be reduced as much as possible.

[0033] Furthermore, when the injection and oxygen enrichment are resumed, coal is injected first and then oxygen enrichment is performed.

[0034] Furthermore, the wind is stopped and the material surface is lowered to 5.5-6m.

[0035] Furthermore, in the early stage of air supply, air is added to 300kPa in several times; in steps, 0-200kPa time is 20min; 200kPa is stable for 5min; 200-240kPa time is 14min; 240kPa is stable for 17min; 240-300kPa time is 10min.

[0036] The beneficial effects of the present invention are:

[0037] The invention shortens the time of restoring full wind to 35% of the original time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the blast furnace structure of the present invention. DETAILED DESCRIPTION

[0039] The present invention is described in detail below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should belong to the scope of protection of the present invention.

[0040] Example 1

[0041] 1. Precautions for wind-break materials and wind-break process

[0042] It is expected that the wind will stop at 8:00 on October 24, and the material level will drop to 5.5-6 meters.

[0043] 1. At 1:00 on October 24 (the time of entering the furnace), one can of coke was added and 5 tons of manganese ore was used instead of sintering (to increase the heat of coke and to serve as a function before the wind is shut down).

[0044] 2. After adding coke, the load is reduced to 4.21, the ore batch is 42 tons, sintering is 63% + pellet ore is 25% + lump ore is 12%, and the coke batch is 9.98 tons.

[0045] 3. At 4:30 on the 24th, 3 cans of coke and 15 tons of manganese ore were added instead of sintering (based on volume measurement, the first can of coke reached the upper part of the furnace waist).

[0046] After adding coke, 40 tons of ore batches are withdrawn, the load is brought to 4.01, 62% + pellet ore 26% + lump ore 12% are sintered, and the coke batch is 9.98 tons (10 batches are taken).

[0047] 5. At 6:10, add 2 more cans of coke and 10 tons of manganese ore instead of sintering.

[0048] Ore batch 40 tons, load to 4.01, sintering 62% + pellet 26% + lump 12%, coke batch 9.98 tons.

[0049] At 7:40, add another can of coke and 5 tons of manganese ore instead of sintering.

[0050] Ore batch 40 tons, load to 4.01, sintering 62% + pellet 26% + lump 12%, coke batch 9.98 tons.

[0051] 2. Operation inside the furnace after re-airing

[0052] 1. After the furnace wall is treated, the furnace top is ready for discharge and 1-2 cans (9.98 tons) of coke are added.

[0053] 2. Block the four air vents (5#9#19#23#) before supplying air. Requirements: Block them firmly with bricks and they cannot be opened without poking.

[0054] 3. Before supplying air, contact and confirm with relevant types of work and positions (under the trough, fan room, pump room, slag flushing), and only supply air after confirmation.

[0055] 4. The foreman will send air to the exhaust valve 5 minutes in advance according to the progress of furnace maintenance.

[0056] 5. When the wind pressure is greater than 50kPa, the conditions for more than 8 spray guns to supply air are met, and the coal sprayers are notified to supply compressed air (coal spray carrier) and watch the water workers start shooting.

[0057] 6. In the early stage of air supply, add air to 300kPa in several times in steps. 0-200kPa takes 20 minutes, 200kPa stabilizes for 5 minutes, 200-240kPa takes 14 minutes, 240kPa stabilizes for 17 minutes, 240-300kPa takes 10 minutes. The air adding process can be slowed down and air can be added gradually depending on the situation of the transmittance indicator.

[0058] 7. After the material starts moving, gradually resume coal injection and oxygen enrichment (first coal injection and then oxygen enrichment), and expand the ore batch and increase the load as soon as possible, which will help to fill the material line as soon as possible.

[0059] 8. After the material moves, iron is tapped in front of the furnace.

[0060] The control of cloth angle and cloth turns during air supply is shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] The technical requirements of the present invention are:

[0065] 1. Add a can of heating coke to ensure that it reaches the furnace when the wind is stopped, and ensure that the Si content of molten iron is above 0.45% before the wind is stopped.

[0066] 2. After adding hot coke, reduce the coke load to 87-89% of the original load.

[0067] 3. Add 3 cans of coke, which will reach the upper part of the furnace waist when the air is off, to ensure the furnace temperature of the second furnace of iron after air is supplied.

[0068] 4. After adding coke, reduce the coke load to 82-84% of the original load.

[0069] 5. After air supply, if the material line depth exceeds 4 meters, the coke ring belt should be collected. The material line within 4 meters should be 1 meter deep and the coke angle should be 2°. For material lines above 5 meters, multi-ring material laying becomes meaningless. The coke ring belt should be reduced as much as possible to prevent the edge from being too heavy.

[0070] 6. In the early stage of air supply, add air to 300kPa several times. The air adding process can be slowed down later, and air can be added gradually depending on the situation of the transmittance.

[0071] The ventilation was restored by the method of the present invention, and the monitoring data of the ventilation were shown in Table 2.

[0072] Table 2

[0073]

Claims

1. A method for quickly restoring blast furnace after long-term shutdown, characterized in that: Rest process: S1. Add 1 tank of coke and 5 tons of manganese ore instead of sintering; after adding coke, the load is reduced to 4.21, the ore batch is 42 tons, including 63% sintered ore, 25% pelletized ore and 12% lump ore, and the coke batch is 9.98 tons; S2. Add 3 cans of coke and 15 tons of manganese ore instead of sintering. According to volume calculation, the first can of coke reaches the upper part of the furnace waist; After adding coke, the ore batch is 40 tons, the load is 4.01, including 62% sinter, 26% pellets and 12% lump ore, the coke batch is 9.98 tons, and 10 batches are taken; S3. Add 2 more cans of coke and 10 tons of manganese ore instead of sintering; Ore batch 40 tons, loaded to 4.01, including 62% sinter, 26% pellets and 12% lump ore, coke batch 9.98 tons; S4. Add another tank of coke, 5 tons of manganese ore instead of sintering, 40 tons of ore batch, load to 4.01, including 62% sintering, 26% pellets and 12% lump ore, 9.98 tons of coke batch; Rewind operation: After the furnace wall is treated, wait until the furnace top is ready for discharge and add 1-2 cans of coke; Before supplying air, block the four air vents with bricks to make them firm and cannot be opened without poking; Before supplying air, check with the trough, fan room, pump room, and slag flushing room to confirm everything. Supply air only after confirmation. The foreman sent the air to the exhaust valve 5 minutes in advance according to the maintenance progress in front of the furnace; When the wind pressure is greater than 50kPa, the conditions for more than 8 spray guns to supply air are met, and the coal sprayer is notified to supply compressed air and the water worker is required to start the spraying; In the early stage of air supply, add air several times to 300kPa; After the material is moving, resume coal injection and oxygen enrichment, expand the ore batch, increase the load, ore batch 40 tons, coke batch 9 tons, load 4.44, fill the material line; After the material moves, iron is tapped in front of the furnace.

2. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: When supplying air, control the cloth angle and cloth turns as follows: The material line is 1.4m, the angle and number of circles of the mine platform are 33°2 circles, 31.3°3 circles, 29.3°3 circles, 27°2 circles, 24.3°2 circles; the angle and number of circles of the coking platform are 35.3°3 circles, 33.1°3 circles, 30.3°2 circles, 27.3°2 circles, 23.8°1 circle, 13°3 circles; The material line is 1.4-1.8m, the angle and number of circles of the mine platform are 32°2 circles, 30.3°3 circles, 28.3°3 circles, 26°2 circles, 23.3°2 circles; the angle and number of circles of the coking platform are 34.3°3 circles, 32.1°3 circles, 29.3°2 circles, 26.3°2 circles, 22.8°1 circle, 13°3 circles; The material line is 1.8-2.2m, the angle and number of circles of the mine platform are 31°2 circles, 29.3°3 circles, 27.3°3 circles, 25°2 circles, 22.3°2 circles; the angle and number of circles of the coking platform are 33.3°3 circles, 31.1°3 circles, 28.3°2 circles, 25.3°2 circles, 21.8°1 circle, 13°3 circles; The material line is 2.2-2.6m, the angle and number of circles of the mine platform are 30°2 circles, 28.3°3 circles, 26.3°3 circles, 24°2 circles, 21.3°2 circles; the angle and number of circles of the coking platform are 32.3°3 circles, 30.1°3 circles, 27.3°2 circles, 24.3°2 circles, 20.8°1 circle, 13°3 circles; The material line is 2.6-3.3m, the angle and number of circles of the mine platform are 29°2 circles, 27.3°3 circles, 25.3°3 circles, 23°2 circles, 20.3°2 circles; the angle and number of circles of the coking platform are 31.3°3 circles, 29.1°3 circles, 26.3°2 circles, 23.3°2 circles, 19.8°1 circle, 13°3 circles; The material line is 3.3-4.0m, the angle and number of circles of the mine platform are 28°2 circles, 26°3 circles, 23°2 circles, and 20°2 circles; the angle and number of circles of the coking platform are 30.5°3 circles, 28.5°3 circles, 26°2 circles, 23°2 circles, 19.5°1 circle, and 13°3 circles; The material line is 4.0-5.0m, the angle and number of circles of the mine platform are 26.5°2 circles, 24.5°3 circles, 21°3 circles, 18°2 circles; the angle and number of circles of the coking platform are 29°3 circles, 27°3 circles, 24.5°2 circles, 21°2 circles, 18°1 circle, 13°3 circles; The material line is 5.0-6.0m, the angle and number of circles of the mine platform are 25°2 circles, 23°3 circles, 20°3 circles, 17°2 circles; the angle and number of circles of the coking platform are 27°3 circles, 25°3 circles, 22°2 circles, 19°2 circles, 16°1 circle, 13°3 circles; The material line is 6.0-7.0m. The feeding angle and number of feeding circles of the mining platform are 23°2 circles, 20°3 circles, and 16.5°2 circles; the feeding angle and number of feeding circles of the coking platform are 25°3 circles, 23°3 circles, 20°2 circles, 17°2 circles, 23.8°1 circle, and 13°3 circles.

3. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: The time interval between step S1 and step S2 is 3.5 hours, the time interval between step S2 and step S3 is 100 minutes, and the time interval between step S3 and step S4 is 90 minutes.

4. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: The silicon content in the molten iron is controlled to be above 0.45% before the wind is shut down.

5. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: After air supply, if the material line is more than 4 meters deep, a coke ring belt will be collected. If the material line is within 4 meters, the coke angle will be collected at 1 meter and 2°.

6. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: When resuming coal injection and oxygen enrichment, inject coal first and then oxygen enrichment.

7. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: Stop the wind and lower the material level to 5.5-6m.

8. A method for quickly restoring blast furnace after long-term shutdown according to claim 1, characterized in that: During the re-air operation, air is added to 300kPa several times in the early stage of air supply; in steps, 0-200kPa time is 20min, 200kPa is stable for 5min, 200-240kPa time is 14min, 240kPa is stable for 17min, and 240-300kPa time is 10min.

Images