CN116103455A - Method for improving iron slag heat in long-term blowing-down and re-blowing initial stage of copper cooling wall blast furnace - Google Patents
Method for improving iron slag heat in long-term blowing-down and re-blowing initial stage of copper cooling wall blast furnace Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/006—Automatically controlling the process
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/007—Conditions of the cokes or characterised by the cokes used
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2300/00—Process aspects
- C21B2300/04—Modeling of the process, e.g. for control purposes; CII
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Abstract
The invention relates to the technical field of blast furnace ironmaking, in particular to a method for improving the heat of slag iron in the long-term damping down and re-blowing initial stage of a copper cooling wall blast furnace, which comprises the following steps: 1) The coke ratio is increased by 10-15 kg/t in two smelting periods before the blast furnace is in a damping-down state; 2) Determining a basic coke ratio of a damping down material according to the damping down time; 3) Adding empty coke according to the length of the damping-down time; 4) Adjusting the flow rate of cooling water of the cooling wall to 1.0m/s within 6-8 hours after the damping down, and adjusting the flow rate of water of the water cooling pipe at the bottom of the furnace to 0.6-0.7 m/s; 5) After re-wind, wind is fast added to make the wind supply ratio reach 0.5, namely the wind quantity/furnace capacity reaches 0.5; 6) After the steps 1) to 5) are adopted, the temperature of the slag iron in the hearth is increased from 1300 ℃ to 1350 ℃ to 1400 ℃ to 1450 ℃ to reach a temperature higher than the free flowing temperature of the slag iron, so that the heat of the slag iron is rapidly increased after the copper cooling wall blast furnace has been subjected to long-term damping down and re-blowing, and the furnace condition is recovered. The invention greatly reduces coke consumption and basically solves the problem that the air supply recovery of the copper cooling wall blast furnace is difficult for a long time.
Description
Technical Field
The invention relates to the technical field of blast furnace ironmaking, in particular to a method for improving the heat of slag iron in the long-term damping down and re-blowing initial stage of a copper cooling wall blast furnace.
Background
At present, a copper cooling wall is generally used from a furnace belly to a furnace waist to the lower part of the furnace body when the middle and large-sized blast furnace is designed and built, and has the advantages of high heat conduction performance, good thermal shock resistance, hot-blast shock resistance and the like, so that a protective slag skin is easy to form on the hot surface of the copper cooling wall in the production process of the blast furnace. But once the slag crust falls off in a large area, the furnace temperature is low, and even the furnace cooling accident is caused.
The blast furnace usually needs to be overhauled once after 3 to 4 months of operation, and has been down for 16 to 48 hours. The furnace temperature is gradually reduced because no coke burns and heat brought by hot air is generated in the furnace during the period of damping down and stopping production, and particularly the furnace is provided with a copper cooling wall, the high heat conductivity of copper causes the heat in the furnace to be rapidly dissipated, and the hearth temperature is further reduced. When the furnace is in a damping down and re-blowing for a long time, the slag iron heat quantity is poor and the fluidity is poor due to low furnace hearth temperature, so that the abnormal air flow distribution is easily caused in the process of recovering the furnace condition, malignant furnace condition disorders such as material collapse, material suspension, pipeline formation and the like are caused, the re-blowing process is influenced, and the fuel consumption is increased.
Therefore, in order to achieve the green low-carbon metallurgical goal, the iron slag heat in the initial stage of re-blowing after long-term blowing down of the copper cooling wall blast furnace must be improved as much as possible, so as to shorten the process of recovering the furnace condition, further reduce the fuel consumption and reduce the carbon emission.
The method aims to provide a method for improving the iron slag heat in the initial stage of long-term blowing-down and re-blowing of the copper cooling wall blast furnace, and aims to adjust the blowing-down coke ratio, the empty coke position and the cooling water amount in the blowing-down period according to different blowing-down time periods when the copper cooling wall blast furnace is in long-term blowing-down, so that the iron slag heat in the initial stage of re-blowing is improved greatly, the furnace condition recovery time is shortened, and the fuel consumption is reduced.
Disclosure of Invention
The invention aims to solve the problems and provides a method for improving the heat of slag iron in the long-term damping down and re-blowing initial stage of a copper cooling wall blast furnace.
Aiming at the long-term blowing down of the copper cooling wall blast furnace, the blowing down coke ratio, the empty coke position, the cooling water quantity during the blowing down period and the blowing down rhythm are adjusted according to different blowing down time, so that the slag iron heat quantity in the initial stage of blowing down is greatly improved, the furnace condition recovery time is shortened, and the fuel consumption is reduced. The purpose of the invention is realized in the following way:
a method for improving the heat of slag iron in the long-term damping down and re-blowing initial stage of a copper cooling wall blast furnace comprises the following steps: 1) The coke ratio is improved by 10-15 kg/t in two smelting periods before the blast furnace is in damping down; 2) Determining a basic coke ratio of a damping-down material according to the damping-down time, and applying a formula (1)
K Damping material ＝K Normal material +h Duration of damping down ×1.5(1)
Wherein:
K damping material -damping down material coke ratio, kg/t;
K normal material Normal coke ratio, kg/t;
h duration of damping down -duration of damping-down, h; by counting the data of heat loss during the damping down period and heat loss caused by the fact that coal cannot be sprayed after air supply, the basic coke ratio of the damping down material of the whole furnace is increased by 1.5kg/t every damping down for 1 h; the charging coke ratio in a smelting period before blowing down is K Damping material Until damping down; 3) Adding empty coke according to the length of the damping-down time, and adding the number n of the empty coke Empty coke Calculated by formula (2);
n empty coke ＝h Time of damping down /16+0.5(2)
Wherein:
n empty coke -the number of hollow coke in the damping down material is rounded to an integer, and the number is a whole;
h time of damping down -planning the number of hours from the start of the damping-down to the resumption of the damping-down;
long-term damping down within 60 hours, and adding hollow coke in damping down materials;
the method comprises the steps that after the last batch of normal materials are charged, blowing down is carried out, and a first group of empty coke positions are positioned at the upper part of a blast furnace belly; 4) The blast furnace still has direct reduction reaction of furnace charge after the blowing down, and molten slag iron can continuously drip into the hearth, so the flow rate of cooling water of the cooling wall is adjusted to 1.0m/s 6-8 hours after the blowing down, and the flow rate of water of a water cooling pipe at the bottom of the furnace is adjusted to 0.6-0.7 m/s; 5) After re-wind, wind is fast added to make the wind supply ratio reach 0.5, namely the wind quantity/furnace capacity reaches 0.5; 6) After the steps 1) to 5) are adopted, the temperature of the slag iron in the hearth is increased from 1300 ℃ to 1350 ℃ to 1400 ℃ to 1450 ℃ to reach the temperature above the free flowing temperature of the slag iron, so that the heat of the slag iron is quickly increased after the copper cooling wall blast furnace has been subjected to long-term damping down and re-blowing, and the furnace condition is recovered.
The long-term damping-down space coke adding mode in the step 3) is damping-down time length of 8h, the number of space coke is 1, and the arrangement mode is (1C+x delta) plus y delta; the damping-down time is 12h, the number of empty coke is 1, and the arrangement mode is (1C+x delta) + (1C+x delta) +ydelta; the damping-down time is 24 hours, the number of empty coke is 2, and the arrangement mode is (1C+x delta) + (1C+x delta) +ydelta; the damping-down time is 36h, the number of empty coke is 3, and the arrangement mode is (2C+x delta) + (1C+x delta) +ydelta; the damping-down time is 48h, the number of empty coke is 4, and the arrangement mode is (2C+x delta) + (1C+x delta) +y delta; the damping-down time is 60h, the number of empty coke is 4, and the arrangement mode is (2C+x delta) + (1C+x delta) +y delta;
x is the batch number of normal materials loaded after empty coke, and is calculated by a formula (3);
x＝(V working volume ×0.85/(1-η Compression )-V Empty coke ×n Empty coke )/V Batch volume /8 (3)
Wherein:
x, the batch number of normal materials is filled after empty coke;
V working volume -working volume of blast furnace, m 3 ；
η Compression The average compression rate of furnace burden is 10-12%, 1000m 3 Lower limit of blast furnace, 4000m 3 Taking the upper limit of the grade blast furnace;
V empty coke -volume of single empty focus, m 3 ；
n Empty coke The number of empty coke;
V batch volume Per volume of batch, m 3 ；
y is the batch number which needs to be loaded after the last empty coke and x normal materials are loaded until the time of blowing down, and is calculated by a formula (4);
wherein:
Σx—after each group of empty coke, loading the sum value of the normal material x, one;
V working volume -effective volume of blast furnace, m 3 ；
η Compression The average compression rate of furnace burden is 10-12%, 1000m 3 Lower limit of blast furnace, 4000m 3 Taking the upper limit of the grade blast furnace;
V empty coke -volume of single empty focus, m 3 ；
n Empty coke The number of empty coke;
V batch volume Per volume of batch, m 3 。
Step 4) specifically adjusts the rhythm as follows: during normal production, the water flow rate of the hearth cooling wall is 2.7m/s, and the water flow rate of the furnace bottom water cooling pipe is 2.0m/s; 1 hour after the damping down, the water flow rate of the hearth cooling wall is 2.10m/s, and the water flow rate of the furnace bottom water cooling pipe is 2.0m/s; 2 hours after the damping down, the water flow rate of the hearth cooling wall is 1.80m/s, and the water flow rate of the furnace bottom water cooling pipe is 1.60m/s; 4 hours after the damping down, the water flow rate of the hearth cooling wall is 1.40m/s, and the water flow rate of the furnace bottom water cooling pipe is 1.20m/s; 6 hours after the damping down, the water flow rate of the hearth cooling wall is 1.00m/s, and the water flow rate of the furnace bottom water cooling pipe is 0.60m/s. The beneficial effects of the invention are as follows: 1. 1800m of Tai steel ironworks 3 The method is used for the blast furnace, the temperature of slag iron in the initial stage of re-blowing is increased from 1300 ℃ to 1400 ℃ in the long-term blowing-down of the definite inspection, the blowing-in recovery time is shortened from more than 24 hours to 10 hours, the coke consumption is greatly reduced, and the problem that the blowing-in recovery of the copper cooling wall blast furnace is difficult is basically solved. 1800m of 2022, 4 and 13 day Tai steel iron works 3 The blast furnace is subjected to fixed inspection and has a blowing-down period of 47h, 15 days of re-blowing for 4 months, and the full blowing is recovered for 10h, so that compared with the conventional blowing-down period of more than 40h, the yield loss is reduced by 1000t, the coke consumption is reduced by 120t, and the economic benefit is 100 ten thousand yuan.
2. The copper cooling wall technology is widely used at home and abroad, and by using the patent, the recovery of a blast furnace can be greatly shortened, the working strength of workers is reduced, and the copper cooling wall technology has remarkable benefits in the aspects of environmental protection, safety, greenness, low carbon, high efficiency and the like and has stronger popularization value.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a view showing the position of the empty coke in the blast furnace according to the present invention.
Wherein: 1. third group of empty coke, 2. Second group of empty coke, 3. First group of empty coke.
Detailed Description
The invention adopts the basic technical conception: the copper cooling wall blast furnace utilizes the high heat conductivity of copper to quickly generate slag skin with low heat conductivity, and plays roles of protecting the cooling wall and regulating air flow. In the past, the furnace is often washed in advance when the furnace is in a long-term damping down, so that slag skin attached to a copper cooling wall falls off in a large area, and the furnace temperature is increased through high fuel ratio to keep the heat of slag iron. The invention keeps the adhesive capacity of the slag skin by adjusting before the damping down, avoids the falling of the slag skin, reduces the heat loss in the damping down process, reduces the disturbance of the coal gas flow to the slag skin in the initial stage of the damping down, and simultaneously supplements the heat as soon as possible so as to quickly improve the heat of slag iron in the initial stage of the damping down and shorten the recovery time of furnace conditions.
The invention provides a method for improving the heat quantity of slag iron in the long-term damping-down and re-blowing initial stage of a copper cooling wall blast furnace, which comprises the following steps: 1. the coke ratio is increased by 1.5 times the number of the blowing-down hours kg/t in a smelting period before blowing-down according to the blowing-down time of the blast furnace. 2. Adding empty coke according to the length of the damping-down time, wherein the number of the empty coke is (damping-down hours/16+0.5), and the first empty coke is positioned at the middle upper part of the furnace belly. 3. Reducing the cooling water quantity within 6-8 hours after the damping down, controlling the flow according to the cooling wall water flow rate of 1.0m/s and the furnace bottom water cooling pipe water flow rate of 0.6m/s, and strengthening the adhesion of slag crust. 4. After the air is recovered, the air quantity of the furnace is improved by adopting a mode of adding air for a plurality of times in a small amplitude, the normal descent of the furnace burden is maintained, and the slag skin is eliminated from falling off greatly.
The specific technical scheme of the invention is as follows.
1. The coke ratio is increased by 10-15 kg/t in two smelting periods before the blast furnace is in damping down.
2. Determining a basic coke ratio of a damping-down material according to the damping-down time, wherein the invention applies a formula (1):
K damping downMaterial ＝K Positive production material +h Duration of damping down ×1.5(1)
Wherein:
K damping material -damping down material coke ratio, kg/t;
K normal material Normal coke ratio, kg/t;
h duration of damping down -duration of damping-down, h;
by counting the heat loss during the damping down period and the data of heat deficiency caused by the fact that coal cannot be sprayed after air supply, the basic coke ratio of the damping down material of the whole furnace is increased by 1.5kg/t every damping down for 1 h. The charging coke ratio in a smelting period before blowing down is K Damping material Until the damping down is completed.
3. Adding empty coke according to the length of the damping-down time, and adding the number n of the empty coke Empty coke Calculated by equation (2).
n Empty coke ＝h Time of damping down /16+0.5 (2)
Wherein:
n empty coke -the number of hollow coke in the damping down material is rounded to an integer, and the number is a whole;
h time of damping down -planning the number of hours from the start of the break to the resumption of the break.
The mode of adding hollow coke in the damping down material after long-term damping down within 60 hours is shown in table 1.
TABLE 1 Long-term damping-down Coke addition method
In the table, x is the batch number of normal materials charged after empty coke, and is calculated by the formula (3).
x＝(V Working volume ×0.85/(1-η Compression )-V Empty coke ×n Empty coke )/V Batch volume /8 (3)
Wherein:
x, the batch number of normal materials is filled after empty coke;
V working volume -working volume of blast furnace, m 3 ；
η Compression The average compression rate of furnace burden is 10-12%, 1000m 3 Lower limit of blast furnace, 4000m 3 Taking the upper limit of the grade blast furnace;
V empty coke -volume of single empty focus, m 3 ；
n Empty coke The number of empty coke;
V batch volume Per volume of batch, m 3 。
In table 1, y is the batch number to be charged from the last empty coke and x normal materials to the time of blowing down, and is calculated by the formula (4).
Wherein:
Σx—after each group of empty coke, loading the sum value of the normal material x, one;
V working volume -effective volume of blast furnace, m 3 ；
η Compression The average compression rate of furnace burden is 10-12%, 1000m 3 Lower limit of blast furnace, 4000m 3 Taking the upper limit of the grade blast furnace;
V empty coke -volume of single empty focus, m 3 ；
n Empty coke The number of empty coke;
V batch volume Per volume of batch, m 3 。
And (3) calculating the quantity of the charged empty coke and the quantity of normal materials according to the formula (2), the formula (3) and the formula (4), and damping down the last batch of normal materials when the first group of empty coke is positioned at the upper part of the blast furnace belly, namely the position shown in figure 1.
4. The blast furnace still has the direct reduction reaction of furnace charge in the back of blowing down, and molten slag iron can continuously drip in the hearth simultaneously, if still keeps great cooling strength this moment, on the one hand can condense more slag iron on the copper cooling wall and lead to slag skin thickening, increases the risk of droing, on the other hand cooling water takes more heat from the hearth, further reduces the temperature of slag iron. Therefore, the cooling water quantity of the furnace body is adjusted after the blowing down, the cooling strength is properly reduced, and the stability of slag skin and the maintenance of the heat quantity of slag iron in a hearth are facilitated. Because the cooling water quantity of different blast furnaces is different, the control is carried out according to the actual flow rate of the cooling water in the cooling equipment, the flow rate of the cooling water of the cooling wall is adjusted to 1.0m/s 6-8 hours after the damping down, and the flow rate of the water cooling pipe at the bottom of the furnace is adjusted to 0.6-0.7 m/s. The specific adjustment rhythm is shown in table 2.
TABLE 2 copper cooled wall blast furnace long-term damping down cooling water adjustment mode
5. After re-wind, wind is fast added to make the wind supply ratio reach 0.5, i.e. the wind quantity/furnace volume reach 0.5, and the wind quantity/furnace volume is 2000m 3 For example, the initial air volume of the blast furnace should reach 1000m 3 And/min. Then adopting a mode of adding air for multiple times with small amplitude, and adding air for 100-300 m every 7-10 min 3 The speed per min increases the furnace inlet air quantity by 1000m 3 Lower limit of blast furnace, 4000m 3 The upper limit of the grade blast furnace is adopted, so that the furnace burden can be kept to normally descend, and slag skin attached to the copper cooling wall can be kept stable, and falling is avoided.
6. After 1 to 5 steps are adopted, the blast furnace slag skin can be stably attached and does not fall off, the consumed heat of the copper cooling wall is greatly reduced, the heat load of the blast furnace is stable, the lost heat is reduced, meanwhile, along with the improvement of the entering air quantity, additional empty coke in the blowing-down material quickly reaches the air port area to burn and heat, the heat of slag iron in the hearth is further improved, the heat of slag iron of the copper cooling wall blast furnace is quickly improved after long-term blowing-down and re-blowing, and the recovery of furnace conditions is facilitated.
The method is carried out on Tai steel 1800m 3 The blast furnace is better used, and the 2022, 4-month and 13-day damping down is taken as an example, and the concrete implementation scheme is as follows: 1. planning and checking for 40h, and planning the air-break time: 4 month 13 day 4: 30-14 days 20:30. 2. The structure of the raw fuel is as follows: 72% sinter+28% Yuan Qiu +silica, 80% metallurgical coke+20% intermediate bulk coke. 3. Damping down material loading sequence: 12 Delta++ (2C+6 Delta) + (1C+6 DELTA+ (6tC+6 DELTA) +10 DELTA, 40 batches total, 49t for ore, 13.9t for coke batch (empty coke) (17.6/10.2), 0.5t for coke, 3 empty coke, and a normal feed coke ratio of 450kg/t. Full furnace coke ratio 487kg/t, coke ratio 494kg/t above tuyere and coke ratio 503kg/t above empty coke. 4. Empty coke loading position: the first is arranged at the middle upper part of the furnace belly, the second empty coke is arranged at the lower part of the 8 sections of cooling walls of the furnace body, and 22 batches of normal materials are arranged above the empty coke. 5. The actual blowing-down time is 4:30 on 13 days to 3:26 on 15 days of 4 months, and the actual blowing-down time is 46h and 56min. 6. A water regulating scheme during the period of damping down.
TABLE 3 copper cooled wall blast furnace long-term damping down cooling water adjustment mode
Air supply is started at a speed of 3:26 in 15 days of 4 months, then air is gradually added at normal pressure, and air is added at a speed of 4:30 to 1700m 3 And/min. The accumulated air quantity is 10 ten thousand, and coal injection is started. 5:40 wind is added to 2000m 3 And/min. 6:36 accumulated air quantity is 28 ten thousand, a south iron notch is opened, the tapping time of the first furnace is shorter, and tapping is carried out for 30min. The ore expansion batch is 7:30 to 39t, and the coke ratio is 450 to 408. After the first furnace is closed, the large trench is cleaned, a second furnace south field is opened in a ratio of 7:57, the temperature is measured at 1407 ℃, and the temperature is measured at 1445 ℃ in the later stage. 10:34, the door is closed, tapping is carried out for 2h37min, tapping is carried out for 120t, tapping is carried out for 30t, molten iron Si is 1.41, and slag alkalinity R2 is 1.06. 11:09 south field third furnace opening, 30min to remove slag, water slag, temperature measurement 1443 ℃, molten iron Si1.53 and slag alkalinity R2 of 1.16. 12:56 closing the door. Then gradually adding air to expand ore batches, charging load and adding air to 3050m according to the air flow in the furnace and the heat and discharge condition of slag iron in front of the furnace, wherein the air is 13:30 3 Per min (90% of normal air quantity), 11000m of oxygen 3 And/h, finishing air supply recovery.
Compared with the traditional damping-down for more than 40 hours, the damping-down recovery of the regular test from 13 days of 4 months to 15 days of 4 months reduces the yield loss by 1000t, reduces the coke consumption by 120t and has the economic benefit of 100 ten thousand yuan.
Taking 2021, 9 and 14 days of damping down as an example, specific embodiments are as follows: 1. planning and checking for 24 hours, and planning the air-break time: day 3:00 of 9 months 14 to day 3:00 of 15 days. 2. The structure of the raw fuel is as follows: 72% sinter+15% Yuan Qiu +13% Emei balls+silica, 100% outsourced coke. 3. Damping down material loading sequence: 12 Delta+ (2C+6 Delta) + (1C+6 Delta) +16 Deltaj, 40 batches, 49t ore batch, 13.0t coke batch (empty coke), 0.5t coke batch, 3 empty coke batch, and 440kg/t normal feed coke ratio. Full furnace coke ratio 472kg/t, tuyere upper coke ratio 475kg/t, empty coke upper coke ratio 489kg/t. 4. Empty coke loading position: the first is arranged at the middle upper part of the furnace belly, the second empty coke is arranged at the lower part of the 8 sections of cooling walls of the furnace body, and 22 batches of normal materials are arranged above the empty coke. 5. The actual blowing-down time is 9 months, 14 days, 3:00 to 15 days, 4:56, and the actual blowing-down time is 25h and 56min. 6. A water regulating scheme during the period of damping down.
TABLE 4 copper cooled wall blast furnace long-term damping down cooling water adjustment mode
Air supply is started at a speed of 4:56 in 15 days of 9 months, then air is gradually added at normal pressure, and air is added at a speed of 5:30 to 1500m 3 And/min. The accumulated air quantity is 10 ten thousand, and coal injection is started. 5:40 wind is added to 2000m 3 And/min. And 5, placing a stock rod stock level at a ratio of 09, wherein the north rule is 3.37m, and the south rule is 3.43m. The starting material is obvious in 5:18, the north rule of the 5:57 stockline is 3.85m, the south rule is 3.96m, and the first tank material (air quantity 1640m 3 /min)。
6:10 air volume is added to 1700m 3 And/min, accumulating the air quantity for 10 ten thousand, and starting coal injection.
6:45 (air supply 1h49 min) to 2000m 3 And/min. Maintaining the air quantity to be 2000m 3 The reaction time/min is not movable.
And the accumulated air quantity is 28 ten thousand in 7:40, the iron notch of the south field is opened, after the iron notch is opened, the slag skimmer is changed to be used for measuring the temperature of 1352 ℃ at the initial stage of tapping and 1407 ℃ at the later stage. 10:07 closing the door, tapping for 2h27min, and tapping for 220t.
After the emission of the south field is smooth, air is added into the furnace, and the air is added to 2500m from 9:46 3 min, batch size up to 36t, and coke ratio 440 to 420.
And a second furnace opening of a south field is 10:45, slag is flushed after 15min, and the temperature is measured at 1415 ℃.13:16 blocking and closing the door.
Opening 18# air port at 11:28, gradually adding air, and enabling the air volume to reach 2800m at 12:09 3 And/min, the ore batch is expanded to 40t, and the coke ratio is 406.
The first opening of the north field is 13:29, slag is discharged for 13min, and the temperature is measured at 1370 ℃.13:58 poking out 8# and 22# air openings, and fully opening the air openings.
Adding air to 3000m in a ratio of 14:17 3 And/min, the ore batch is expanded to 44t, and the coke ratio is 395.
And then gradually adding wind to expand ore batches and loading according to the air flow in the furnace, the heat quantity of slag iron in front of the furnace and the discharge condition. Adding air to 3500m at a ratio of 16:40 3 Per min (90% of normal air quantity), and the oxygen is 14000m 3 And/h, ore batch 47t, coke ratio 387. And (5) air supply recovery is completed.
Compared with the conventional 24-hour or more blowing-down recovery, the 2021 9-month 14-month 15-day test blowing-down recovery method shortens the recovery time from 24 hours to 12 hours, reduces the yield loss by 750t, reduces the coke consumption by 80t and has the economic benefit of 82 ten thousand yuan.
The method provides a method for greatly improving the iron heat of slag of a hearth by comprehensively measures such as the coke ratio of the damping down materials, the quantity and the position of the addition of the damping down materials and the empty coke in the long-term damping down and damping down process of the copper cooling wall blast furnace, adjusting the cooling system in the damping down process, controlling the damping down rhythm in the initial damping down stage and the like, eliminating the risk of greatly falling slag skin of the copper cooling wall to reduce the iron heat of slag of the hearth, and greatly shortening the recovery time of the damping down of the copper cooling wall blast furnace after the long-term damping down by matching with the heating effect of the damping down materials and the empty coke, reducing the fuel consumption and the yield loss, thereby laying the foundation for green low-carbon iron making.
The above embodiments are merely examples of the present invention, but the present invention is not limited to the above embodiments, and any changes or modifications within the scope of the present invention are intended to be included in the scope of the present invention.
Claims (3)
1. A method for improving the heat of slag iron in the initial stage of long-term damping down and re-damping down of a copper cooling wall blast furnace is characterized by comprising the following steps: the method comprises the following steps:
1) The coke ratio is improved by 10-15 kg/t in two smelting periods before the blast furnace is in damping down;
2) Determining a basic coke ratio of a damping-down material according to the damping-down time, and applying a formula (1)
K Damping material ＝K Normal material +h Duration of damping down ×1.5(1)
Wherein:
K damping material -damping down material coke ratio, kg/t;
K normal material Normal coke ratio, kg/t;
h duration of damping down -duration of damping-down, h; by counting the data of heat loss during the damping down period and heat loss caused by the fact that coal cannot be sprayed after air supply, the basic coke ratio of the damping down material of the whole furnace is increased by 1.5kg/t every damping down for 1 h; the charging coke ratio in a smelting period before blowing down is K Damping material Until damping down;
3) Adding empty coke according to the length of the damping-down time, and adding the number n of the empty coke Empty coke Calculated by formula (2);
n empty coke ＝h Time of damping down /16+0.5(2)
Wherein:
n empty coke -the number of hollow coke in the damping down material is rounded to an integer, and the number is a whole;
h time of damping down -planning the number of hours from the start of the damping-down to the resumption of the damping-down;
long-term damping down within 60 hours, and adding hollow coke in damping down materials;
the method comprises the steps that after the last batch of normal materials are charged, blowing down is carried out, and a first group of empty coke positions are positioned at the upper part of a blast furnace belly;
4) The blast furnace still has direct reduction reaction of furnace charge after the blowing down, and molten slag iron can continuously drip into the hearth, so the flow rate of cooling water of the cooling wall is adjusted to 1.0m/s 6-8 hours after the blowing down, and the flow rate of water of a water cooling pipe at the bottom of the furnace is adjusted to 0.6-0.7 m/s;
5) After re-wind, wind is fast added to make the wind supply ratio reach 0.5, namely the wind quantity/furnace capacity reaches 0.5;
6) After the steps 1) to 5) are adopted, the temperature of the slag iron in the hearth is increased from 1300 ℃ to 1350 ℃ to 1400 ℃ to 1450 ℃ to reach the temperature above the free flowing temperature of the slag iron, so that the heat of the slag iron is quickly increased after the copper cooling wall blast furnace has been subjected to long-term damping down and re-blowing, and the furnace condition is recovered.
2. The method for improving the iron slag heat in the long-term blowing-down and re-blowing initial stage of the copper cooling wall blast furnace according to claim 1, which is characterized in that: the long-term damping-down space coke adding mode in the step 3) is damping-down time length of 8h, the number of space coke is 1, and the arrangement mode is (1C+x delta) plus y delta; the damping-down time is 12h, the number of empty coke is 1, and the arrangement mode is (1C+x delta) + (1C+x delta) +ydelta; the damping-down time is 24 hours, the number of empty coke is 2, and the arrangement mode is (1C+x delta) + (1C+x delta) +ydelta; the damping-down time is 36h, the number of empty coke is 3, and the arrangement mode is (2C+x delta) + (1C+x delta) +ydelta; the damping-down time is 48h, the number of empty coke is 4, and the arrangement mode is (2C+x delta) + (1C+x delta) +y delta; the damping-down time is 60h, the number of empty coke is 4, and the arrangement mode is (2C+x delta) + (1C+x delta) +y delta;
x is the batch number of normal materials loaded after empty coke, and is calculated by a formula (3);
x＝(V working volume ×0.85/(1-η Compression )-V Empty coke ×n Empty coke )/V Batch volume /8 (3)
Wherein:
x, the batch number of normal materials is filled after empty coke;
V working volume -working volume of blast furnace, m 3 ；
η Compression The average compression rate of furnace burden is 10-12%, 1000m 3 Lower limit of blast furnace, 4000m 3 Taking the upper limit of the grade blast furnace;
V empty coke -volume of single empty focus, m 3 ；
n Empty coke The number of empty coke;
V batch volume Per volume of batch, m 3 ；
y is the batch number which needs to be loaded after the last empty coke and x normal materials are loaded until the time of blowing down, and is calculated by a formula (4);
wherein:
Σx—after each group of empty coke, loading the sum value of the normal material x, one;
V working volume -effective volume of blast furnace, m 3 ；
η Compression The average compression rate of furnace burden is 10-12%, 1000m 3 Lower limit of blast furnace, 4000m 3 Taking the upper limit of the grade blast furnace;
V empty coke -volume of single empty focus, m 3 ；
n Empty coke The number of empty coke;
V batch volume Per volume of batch, m 3 。
3. The method for improving the iron slag heat in the long-term blowing-down and re-blowing initial stage of the copper cooling wall blast furnace according to claim 1, which is characterized in that: step 4) specifically adjusts the rhythm as follows: during normal production, the water flow rate of the hearth cooling wall is 2.7m/s, and the water flow rate of the furnace bottom water cooling pipe is 2.0m/s; 1 hour after the damping down, the water flow rate of the hearth cooling wall is 2.10m/s, and the water flow rate of the furnace bottom water cooling pipe is 2.0m/s; 2 hours after the damping down, the water flow rate of the hearth cooling wall is 1.80m/s, and the water flow rate of the furnace bottom water cooling pipe is 1.60m/s; 4 hours after the damping down, the water flow rate of the hearth cooling wall is 1.40m/s, and the water flow rate of the furnace bottom water cooling pipe is 1.20m/s; 6 hours after the damping down, the water flow rate of the hearth cooling wall is 1.00m/s, and the water flow rate of the furnace bottom water cooling pipe is 0.60m/s.
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