CN112899422A - Material level lowering method for blast furnace shutdown - Google Patents
Material level lowering method for blast furnace shutdown Download PDFInfo
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- CN112899422A CN112899422A CN202110063825.8A CN202110063825A CN112899422A CN 112899422 A CN112899422 A CN 112899422A CN 202110063825 A CN202110063825 A CN 202110063825A CN 112899422 A CN112899422 A CN 112899422A
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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
- C21B7/00—Blast furnaces
- C21B7/10—Cooling; Devices therefor
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Abstract
The invention relates to a charge level lowering method for blast furnace shutdown, which comprises the following steps: s100, providing a blast furnace, wherein a water spraying device is arranged in a furnace throat and is communicated with a water supply pipeline and a nitrogen supply pipeline; s200, debugging a water spraying device to enable the sprayed mixture to be separated from the furnace wall at the minimum output pressure and to be sprayed onto the furnace wall at the maximum output pressure; step S300, stopping feeding and re-airing the blast furnace to enable the charge level to descend; from the highest position to the lowest position of the charge level, the furnace comprises a furnace body, a furnace waist, a furnace belly and a furnace hearth which are sequentially reduced, the water sprinkling device is selectively opened, and the pressure of water and nitrogen is adjusted; when the charge level is on the furnace body, the temperature of the furnace throat is T1; when the charge level is at the furnace waist, the temperature of the furnace throat is T2; when the charge level is in the furnace bosh, the temperature of the furnace throat is T3; when the charge level is in the hearth, the temperature of the throat is T4; and S400, damping down when the charge level is lowered to the lowest position. The method has the characteristics of high furnace shutdown safety and high furnace shutdown efficiency.
Description
Technical Field
The invention relates to the technical field of blast furnace smelting, in particular to a charge level lowering method for blast furnace blowing out.
Background
At present, the design furnace life of a blast furnace is 15 years, and after the production reaches a certain age, the blast furnace needs to be shut down and overhauled. When the blast furnace is stopped, mineral aggregates, coke and the like in the furnace need to be removed, so that the inner wall of the blast furnace is exposed for maintenance. In the prior art, a furnace top water spraying and material level lowering method is generally adopted for blowing out a blast furnace, and the temperature of the top of the blast furnace is controlled by spraying water, so that the situation that surrounding equipment is burnt due to overhigh temperature of the top is avoided. In the process of sprinkling water for cooling, water flows down along the furnace wall to cause the furnace wall to generate a large amount of solidified iron layers, a large amount of working hours are needed to be spent for cleaning the solidified iron layers, and then the total consumption of furnace shutdown operation is increased, and the furnace shutdown efficiency is low.
Disclosure of Invention
The invention aims to provide a charge level lowering method for blast furnace shutdown, which has high safety and high shutdown efficiency.
In order to achieve the purpose, the invention adopts the following technical scheme:
the provided charge level lowering method for blast furnace shutdown comprises the following steps:
s100, providing a blast furnace, damping down the blast furnace, arranging a water spraying device in a furnace throat of the blast furnace, wherein the water spraying device is communicated with a water supply pipeline and a nitrogen supply pipeline, and the water spraying device is used for cooling the furnace throat by spraying a mixture of water and nitrogen;
step S200, debugging the water spraying device, wherein when the working pressure S of spraying water is the minimum output pressure S1 of the water supply pipeline and the working pressure D of spraying nitrogen is the minimum output pressure D1 of the nitrogen supply pipeline, the distance between the mixture and the furnace wall of the blast furnace is L; when the working pressure S of spraying water is the maximum output pressure S2 of the water supply pipeline and the working pressure D of spraying nitrogen is the maximum output pressure D2 of the nitrogen supply pipeline, the mixture can be sprayed onto the furnace wall;
step S300, stopping feeding and re-airing the blast furnace to enable the charge level to descend;
selectively starting the water spraying device and adjusting the working pressure S of water spraying and the working pressure D of nitrogen spraying, wherein S is S1-S2, and D is D1-D2; and the process is carried out in a way that,
when the charge level is positioned in the furnace body, the temperature of the furnace throat is T1;
when the charge level is positioned at the furnace waist, the temperature of the furnace throat is T2;
when the charge level is positioned in the furnace bosh, the temperature of the furnace throat is T3;
when the charge level is positioned in the hearth, the temperature of the throat is T4;
and S400, damping down the blast furnace when the charge level is lowered to the lowest position.
Further, watering device includes a plurality of atomized water pipes, atomized water pipe is used for spraying mixture, at least one atomized water pipe is located the middle part position of furnace throat, remaining all atomized water pipe is followed the even interval distribution of circumferencial direction of furnace throat.
Further, in step S200, the distance L between the mixture and the furnace wall is greater than 50mm, and when the water spraying working pressure S is S2 and the nitrogen spraying working pressure D is D2, the spraying surface of the mixture is equal to the cross section of the furnace throat.
Further, in step S300, when the charge level is located in the furnace body, the temperature T1 is 300 to 400 ℃, the operating pressure S of spraying water is 1.2MPa, and the operating pressure D of spraying nitrogen is 0.6 MPa; when the charge level is positioned at the waist of the furnace, the temperature T2 is 200-350 ℃, the working pressure S of spraying water is 1.2MPa, and the working pressure D of spraying nitrogen is 0.8 MPa; when the charge level is positioned at the furnace belly, the temperature T3 is 150-300 ℃, the working pressure S of water spraying is 1.2MPa, and the working pressure D of nitrogen spraying is 1.0 MPa; when the charge level is positioned in the hearth, the temperature T4 is 300-450 ℃, the working pressure S of water spraying is 1.2MPa, and the working pressure D of nitrogen spraying is 1.0 MPa.
Further, in step S300, the blast air volume of the blast furnace is sequentially decreased as the burden surface is decreased.
Furthermore, during air supply, the input gas comprises high-temperature air and pure oxygen, and the input amount of the pure oxygen is sequentially reduced along with the reduction of the charge level.
Further, in step S300,
when the charge level is positioned on the furnace body, the air supply volume is the air volume in a full-air full-oxygen state;
when the charge level is positioned at the furnace waist, the air supply volume is 60% -90% of the air volume in the full-air full-oxygen state, and the air supply volume is reduced by 1% -5% of the air volume in the full-air full-oxygen state every time the charge level is reduced by 0.2 m;
when the charge level is positioned in the furnace belly, the air supply volume is 30% -60% of the air volume in the full-air full-oxygen state, and the air supply volume is reduced by 1% -5% of the air volume in the full-air full-oxygen state every time the charge level is reduced by 0.2 m.
Further, in step S300, when the charge level is located in the furnace bosh, the pure oxygen input is stopped.
Further, in step S300, during the descending process of the burden surface, sampling and detecting the gas in the furnace throat, wherein the sampling interval time is t.
Further, in step S300, steam is input to the throat at a level lowering stage of the blast furnace, and the pressure of the steam is greater than 0.4 MPa.
Compared with the prior art, the invention has the beneficial effects that:
according to the method for lowering the charge level of the blast furnace blowing out, the water pressure and the nitrogen pressure in the water spraying device are adjusted when the charge level is located at different positions in the charge level lowering process, and the temperature of the furnace throat area is controlled in different ranges, so that the method is favorable for adapting to the temperature change and the gas component change caused by different smelting materials participating in smelting reaction in the charge level lowering process, and further the safety of the blast furnace blowing out is improved. Meanwhile, the phenomenon that the sprayed water flows down along the furnace wall to cause the occurrence of a solidified iron layer during cooling is avoided, the operation of removing the solidified iron layer in the later period is avoided, the total time consumption of furnace shutdown is reduced, and the efficiency of furnace shutdown of the blast furnace is improved.
Drawings
FIG. 1 is a schematic view of a blast furnace according to an embodiment.
In the figure:
1. a housing; 11. a taphole; 12. a slag outlet; 13. an air outlet; 14. a furnace belly; 15. a throat; 16. a feeding device; 17. a furnace body; 18. a furnace waist; 19. a hearth; 2. a refractory layer; 3. a watering device; 4. a ring furnace hot air pipe; 41. a hot air nozzle; 5. a layer of mineral stone; 6. a coke layer; 7. molten iron; 8. slag.
Detailed Description
In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings.
Referring to fig. 1, the invention provides a charge level lowering method for blast furnace shutdown, which is applied to the shutdown treatment of a blast furnace. The method comprises the following steps:
step S100, providing a blast furnace, damping down the blast furnace, arranging a water sprinkling device 3 in a furnace throat 15 of the blast furnace, wherein the water sprinkling device 3 is communicated with a water supply pipeline and a nitrogen supply pipeline, and the water sprinkling device 3 cools the furnace throat 15 by sprinkling a mixture of water and nitrogen;
step S200, debugging the water spraying device 3, wherein when the water spraying pressure S is the minimum output pressure S1 of the water supply pipeline and the working pressure D of the nitrogen spraying is the minimum output pressure D1 of the nitrogen supply pipeline, the distance between the mixture and the furnace wall of the blast furnace is L; when the working pressure S of spraying water is the maximum output pressure S2 of the water supply pipeline and the working pressure D of spraying nitrogen is the maximum output pressure D2 of the nitrogen supply pipeline, the mixture can be sprayed onto the furnace wall;
step S300, stopping feeding and re-airing the blast furnace to enable the charge level to descend;
from the highest position of the charge level to the lowest position of the charge level, the position of the charge level comprises a furnace shell 17, a furnace waist 18, a furnace belly 14 and a furnace hearth 19 which are sequentially reduced, the water spraying device 3 is selectively started, and the working pressure S of water spraying and the working pressure D of nitrogen spraying are adjusted, wherein S is S1-S2, and D is D1-D2; and the process is carried out in a way that,
when the charge level is on the shaft 17, the temperature of the throat 15 is T1;
when the charge level is at the furnace waist 18, the temperature of the furnace throat 15 is T2;
when the charge level is located in the furnace bosh 14, the temperature of the furnace throat 15 is T3;
when the charge level is in the hearth 19, the temperature of the throat 15 is T4;
and S400, damping down the blast furnace when the charge level is lowered to the lowest position.
It should be noted that the working pressure S of the water spraying is that when the sprinkler 3 is started, the water supply pipeline supplies water at the working pressure S; the working pressure D of spraying nitrogen is that when the sprinkler 3 starts, the nitrogen supply pipeline supplies nitrogen at the working pressure D.
It will be appreciated that the blast furnace is a raw iron smelting plant for producing molten iron 7 from iron ore, coke and slag forming solvent by high temperature combustion. The blast furnace includes shell 1 of making with the steel sheet, and shell 1 has the chamber that holds that is used for holding smelting materials such as iron ore, coke, has laid flame retardant coating 2 on shell 1's the inner wall, and the heat that produces when flame retardant coating 2 is used for separation high temperature combustion plays the guard action to shell 1. The blast furnace 1 is divided into five regions from top to bottom, the five regions are a furnace throat 15, a furnace body 17, a furnace waist 18, a furnace bosh 14 and a furnace hearth 19 in sequence, and combustion reaction is carried out in the furnace bosh 14, so that the temperature in the furnace bosh 14 is highest and can reach about 1800 ℃, the temperature is reduced from the furnace bosh 14 to two ends of the blast furnace in sequence, the temperature in the furnace throat 15 region needs to be controlled below 500 ℃, and equipment arranged in the furnace throat 15 region is prevented from being influenced by high temperature. The metallurgical material is discharged from a feeder device 16 located at the top of the blast furnace, wherein a certain amount of iron ore and coke form the ore layers 5 and the coke layers 6, respectively, and the ore layers 5 and the coke layers 6 are alternately stacked in the receiving chamber, i.e. one coke layer 6 is located between two adjacent ore layers 5. The annular ring furnace hot air pipe 4 is arranged at the position of the furnace belly 14 of the blast furnace, the ring furnace hot air pipe 4 is used for conveying high-temperature gas, the high-temperature gas comprises high-temperature air and mixed pure oxygen, the ring furnace hot air pipe 4 is provided with a plurality of hot air nozzles 41 along the circumferential direction of the ring furnace hot air pipe 4, and the hot air nozzles 41 are communicated with the inside of the blast furnace, so that the ring furnace hot air pipe 4 inputs oxygen participating in combustion into the blast furnace through the hot air nozzles 41. Under the action of high-temperature combustion, the ore layer 5 and the coke layer 6 in the furnace chamber 14 are melted to form molten iron 7 or slag 8, and the molten iron 7 and the slag 8 are deposited in the furnace cylinder 19 and discharged through the tap hole 11 and the slag hole 12 respectively. As the layer of ore 5 and the layer of coke 6 in the furnace bosh 14 melt, the layer of ore 5 and the layer of coke 6 located on the top slide down successively and enter the furnace bosh 14. The side surface of the ore layer 5 or the coke layer 6 which is positioned at the top and is close to the top of the blast furnace is the charge level, so the position of the charge level can reflect the quantity of smelting materials in the blast furnace. When the blast furnace is stopped for maintenance, the smelting material in the blast furnace needs to be removed, and the condition that the material level is lowered below the position of the hot blast nozzle 41 can be understood. During smelting, a large amount of coal gas is generated in the blast furnace, is accumulated in the furnace throat 15 and is discharged through the gas outlet 13. In order to avoid the overhigh temperature in the furnace throat 15, the sprinkler 3 is used for cooling, and the water is prevented from flowing down along the furnace wall to generate a solidified iron layer on the furnace wall when the sprinkler is used for cooling.
In this embodiment, the sprinkler 3 is disposed in the furnace throat 15 of the blast furnace, and the sprinkler 3 is used for spraying cooling water to the region of the furnace throat 15, so as to cool the gas in the region, and avoid the influence of the overhigh temperature of the gas in the furnace throat 15 on the equipment installed in the region, such as the feeding device 16 located in the furnace throat 15. The water spraying device 3 is communicated with a water supply pipeline and a nitrogen supply pipeline, the water supply pipeline is used for inputting cooling water to the water spraying device 3, the pressure range of the water supply pipeline is 0.8-1.2 MPa, namely the minimum output pressure S1 of the water supply pipeline is 0.8MPa, and the maximum output pressure S2 of the water supply pipeline is 1.2 MPa; the nitrogen supply pipeline is used for inputting nitrogen to the water spraying device 3, and the nitrogen and the cooling water are mixed to form cooling water in an atomized state, so that heat absorption and evaporation are facilitated. The pressure range of the nitrogen supply pipeline is 0.6-1.0 MPa, namely the minimum output pressure D1 of the nitrogen supply pipeline is 0.6MPa, and the maximum output pressure D2 of the nitrogen supply pipeline is 1.0 MPa. Meanwhile, gas in the furnace throat 15 is discharged to a gas transmission pipeline through the gas outlet 13, a bag-type dust collector is arranged between the gas outlet 13 and the gas transmission pipeline, and the bag-type dust collector is used for filtering the gas and removing particles floating along with the gas.
Before the material level begins to fall, the sprinkler 3 is debugged, so that the mixture (namely cooling water in an atomized state) sprayed by the sprinkler 3 meets the corresponding temperature reduction requirement. The water spraying device 3 in this embodiment includes a plurality of atomized water pipes for spraying the mixture, at least one atomized water pipe is located at the middle position of the furnace throat 15, and the remaining atomized water pipes are evenly spaced along the circumferential direction of the furnace throat 15. This structure is favorable to making the mixture that the atomizing water pipe sprayed distribute evenly, and it is big to spray the area, is favorable to cooling down to the gas in the furnace throat 15. During the adjustment, water is fed through the water supply pipe at the minimum output pressure S1, and nitrogen is fed through the nitrogen supply pipe at the minimum output pressure D1, and the mixture sprayed by the sprinkler 3 forms a spraying surface smaller than the cross section of the furnace throat 15, i.e. the edge position of the mixture is spaced from the furnace wall, and the distance between the two is L. It is also understood that the mixture cannot be sprayed onto the furnace wall. Preferably, L > 50mm, i.e. the mixture sprayed by the sprinkler 3 is spaced from the furnace wall by a distance of more than 50 mm. The mixture sprayed by the sprinkler 3 can be sprayed onto the furnace wall by feeding water through the water feed pipe at a maximum output pressure S2 and nitrogen through the nitrogen feed pipe at a maximum output pressure D2. Preferably, when water and nitrogen are output at the maximum output pressure S2 and the maximum output pressure D2, the spraying surface of the mixture is equal to the cross section of the throat 15, i.e., the mixture is just sprayed onto the furnace wall, and in this state, the mixture can form a full coverage of the throat 15, the cooling effect is the best, and it is avoided that a large amount of water is sprayed onto the furnace wall, causing water to flow down along the furnace wall and form a solidified iron layer. Through the debugging, watering device 3 makes the face of spraying of mixture detect and adjust when minimum output pressure and maximum output pressure, ensures to fall the cooling performance of material face in-process watering device 3.
And after debugging is finished, the burden surface operation is started to drop, the blast furnace stops feeding, and high-temperature air is input into the blast furnace through the ring furnace hot air pipe 4. The blast furnace is in a smelting state, the ore layer 5 and the coke layer 6 in the furnace bosh 14 are melted successively, and the charge level is lowered. The top surface of the smelting material is at the highest position of the material surface when smelting is not started, the smelting material is basically completely melted after smelting is finished, the material surface is positioned below the hot air nozzle 41, and the material surface is at the lowest position at the moment. From the highest level position to the lowest level position, the level position comprises a successively lower shaft 17, waist 18, belly 14 and hearth 19. During the lowering of the charge level, as the smelting proceeds, gases are continuously generated and pass through the smelting material into the region of the throat 15, and the temperature of the throat 15 is raised by the large amount of heat carried by the gases. Therefore, when the temperature in the furnace throat 15 is higher than the maximum limit value, the sprinkler 3 is turned on to spray water for cooling, and when the temperature in the furnace throat 15 is lower than the minimum limit value, the sprinkler 3 is turned off. When the material surface is positioned at different positions during water spraying and temperature reduction, the working pressure S of water spraying of the water spraying device 3 is different from the working pressure D of nitrogen spraying, the working pressure S of water spraying is adjusted between the minimum output pressure S1 and the maximum output pressure S2 of a water supply pipeline, and the working pressure D of nitrogen spraying is adjusted between the minimum output pressure D1 and the maximum output pressure D2 of a nitrogen supply pipeline. And when the charge level is positioned at different positions, the temperature of the furnace throat 15 is controlled within a corresponding temperature value range. Preferably, the capacity is 3200m3For example, in the charge level lowering process, when the charge level is located in the furnace body, the temperature T1 in the furnace throat 15 is controlled to be 300-400 ℃, the working pressure S of water spraying of the water spraying device 3 is 1.2MPa, and the working pressure D of nitrogen spraying is 0.6 MPa; when the charge level is positioned at the furnace waist, the temperature T2 in the furnace throat 15 is controlled to be 200-350 ℃, the working pressure S of water spraying of the water spraying device 3 is 1.2MPa, and the working pressure D of nitrogen spraying is 0.8 MPa; when the charge level is positioned at the furnace belly, the temperature T3 in the furnace throat 15 is controlled to be 150-300 ℃, the working pressure S of water spraying of the water spraying device 3 is 1.2MPa, and the working pressure D of nitrogen spraying is 1.0 MPa; when the charge level is positioned in the hearth, the temperature T4 in the furnace throat 15 is controlled to be 300-450 ℃, and the water spraying device3 the working pressure S of spraying water is 1.2MPa, and the working pressure D of spraying nitrogen is 1.0 MPa. The method controls the temperature of the furnace throat 15 in different ranges by controlling the pressure of water and nitrogen of the sprinkler 3 and enabling the charge level to be positioned at different positions so as to adapt to different temperature changes and different gas components caused by different quantities of smelting materials participating in smelting reaction in the process of lowering the charge level. The method can effectively control the hydrogen content in the furnace throat 15, thereby improving the safety of blast furnace shutdown, avoiding the increase of later cleaning work caused by the solidified iron layer caused by water flowing down along the furnace wall, and further improving the efficiency of blast furnace shutdown.
Specifically, in step S300, the blast air volume of the blast furnace is sequentially decreased as the burden surface is decreased. It can be understood that, as smelting progresses, smelting materials in the blast furnace are gradually reduced, the air supply quantity is reduced, the control of the temperature and the gas content of the furnace throat 15 is facilitated, the material level is kept at a certain descending speed, and material collapse caused by too fast descending of the material level is avoided.
Specifically, when air is supplied, the input gas includes high-temperature air and pure oxygen. In the smelting process, a large amount of oxygen is needed for combustion supporting and participation in chemical reaction. It is therefore necessary to add pure oxygen to the air to increase the oxygen content. The air and pure oxygen are mixed and heated to about 1300 ℃ and then are input into the furnace bosh 14 of the blast furnace through the ring furnace hot air pipe 4. The input amount of pure oxygen is reduced in sequence along with the reduction of the charge level. As can be understood, with the reduction of smelting materials in the blast furnace, the oxygen demand is reduced, the oxygen input is reduced, and the explosion danger caused by the fact that oxygen which does not participate in smelting reaction enters the throat area and is mixed with coal gas is avoided. Preferably, in step S3, when the charge level is located in the furnace shell 17 during the lowering of the charge level, the blast air volume is the air volume in the full-air and full-oxygen state. The full-wind full-oxygen state is the maximum input wind quantity in the normal production state, and the oxygen content in the high-temperature air is also the maximum value. For example: the capacity is 3200m3When the blast furnace is in a full-wind full-oxygen state, the input air quantity is 5800m3Min, oxygen input 21500m3The falling speed of the charge level is high by adopting the air quantity in a full-air full-oxygen state, and the reduction of the charge level is facilitatedThe total time consumption is reduced. When the charge level is positioned at the furnace waist 18, the air supply quantity is 60-90% of the air quantity in the full-air full-oxygen state, the oxygen input quantity is 50% of the oxygen quantity in the full-air full-oxygen state, and the air supply quantity is reduced by 1-5% of the air quantity in the full-air full-oxygen state every time the charge level is reduced by 0.2 m. Meanwhile, every time the charge level is reduced by 0.2m, the oxygen input amount is reduced by 5-10% of the oxygen amount in the full-wind full-oxygen state, so that the pure oxygen input is stopped when the charge level is reduced to the lower end of the furnace waist 18. When the charge level is positioned at the furnace bosh 14, the air supply volume is 30-60% of the air volume in the full-air full-oxygen state, and the air supply volume is reduced by 1-5% of the air volume in the full-air full-oxygen state every time the charge level is reduced by 0.2 m. And stopping air supply when the charge level descends to the set lowest position.
Specifically, in step S300, when the charge level is located in the furnace bosh 14, the input of pure oxygen is stopped. By controlling the oxygen content and the input quantity of high-temperature air, the oxygen content is ensured to be within a safety value in the blowing-out process, the air flow in the blast furnace is prevented from being overturned in the charge level reducing process, and the charge level is ensured to stably reduce.
Specifically, in step S300, during the lowering of the charge level, the gas in the furnace throat 15 is sampled and detected, and the sampling interval time is t. It is understood that this step detects the component content of the gas, including the concentration of carbon monoxide, the concentration of oxygen, etc., by sampling and detecting the gas in the furnace throat 15, so as to monitor and manage the component of the gas. For example, when the oxygen concentration in the gas exceeds the standard, the input amount of the oxygen or the air supply amount can be reduced to meet the requirement of normal operation of the blast furnace, so that accidents are avoided.
Specifically, in step S300, steam is supplied to the throat 15 at a stage of lowering the charge level of the blast furnace, and the pressure of the steam is greater than 0.4 MPa. It is understood that during the smelting process, the produced molten iron 7 and slag 8 are deposited in the hearth 19, and a certain pressure needs to be maintained in the blast furnace so that the molten iron 7 and slag 8 can be smoothly discharged. The position in the blast furnace is within a certain pressure range by inputting steam. Of course, as the burden surface decreases and the blast air volume decreases, the production rate of the molten iron 7 and the slag 8 decreases, or the discharge rate decreases, so that the pressure in the blast furnace decreases as the burden surface decreases or the blast air volume decreases, and the pressure in the blast furnace can be reduced by reducing the steam input pressure and the exhaust of the exhaust valve.
The remarkable effects of the embodiment are as follows: according to the method, the water pressure and the nitrogen pressure in the water spraying device 3 are adjusted when the charge level is at different positions in the charge level lowering process, and the temperature of the furnace throat area is controlled in different ranges, so that the method is favorable for adapting to the temperature change and gas component change caused by different smelting materials participating in smelting reaction in the charge level lowering process, and further the safety of blast furnace blowing-out is improved. Meanwhile, the phenomenon that the sprayed water flows down along the furnace wall to cause the occurrence of a solidified iron layer during cooling is avoided, the operation of removing the solidified iron layer in the later period is avoided, the total time consumption of furnace shutdown is reduced, and the efficiency of furnace shutdown of the blast furnace is improved.
The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.
Claims (10)
1. A charge level lowering method for blast furnace shutdown is characterized by comprising the following steps:
s100, providing a blast furnace, damping down the blast furnace, arranging a water spraying device in a furnace throat of the blast furnace, wherein the water spraying device is communicated with a water supply pipeline and a nitrogen supply pipeline, and the water spraying device is used for cooling the furnace throat by spraying a mixture of water and nitrogen;
step S200, debugging the water spraying device, wherein when the working pressure S of spraying water is the minimum output pressure S1 of the water supply pipeline and the working pressure D of spraying nitrogen is the minimum output pressure D1 of the nitrogen supply pipeline, the distance between the mixture and the furnace wall of the blast furnace is L; when the working pressure S of spraying water is the maximum output pressure S2 of the water supply pipeline and the working pressure D of spraying nitrogen is the maximum output pressure D2 of the nitrogen supply pipeline, the mixture can be sprayed onto the furnace wall;
step S300, stopping feeding and re-airing the blast furnace to enable the charge level to descend;
selectively starting the water spraying device and adjusting the working pressure S of water spraying and the working pressure D of nitrogen spraying, wherein S is S1-S2, and D is D1-D2; and the process is carried out in a way that,
when the charge level is positioned in the furnace body, the temperature of the furnace throat is T1;
when the charge level is positioned at the furnace waist, the temperature of the furnace throat is T2;
when the charge level is positioned in the furnace bosh, the temperature of the furnace throat is T3;
when the charge level is positioned in the hearth, the temperature of the throat is T4;
and S400, damping down the blast furnace when the charge level is lowered to the lowest position.
2. The charge level lowering method for a blast furnace shutdown according to claim 1, wherein the water spraying device includes a plurality of atomized water pipes for spraying the mixture, at least one of the atomized water pipes is located at a middle position of the furnace throat, and all of the atomized water pipes are uniformly spaced in a circumferential direction of the furnace throat.
3. The charge level lowering method for blast furnace shutdown according to claim 1, wherein in step S200, the distance L between the mixture and the furnace wall is greater than 50mm, and the spraying level of the mixture is equal to the cross section of the furnace throat when the water spraying operation pressure S is S2 and the nitrogen spraying operation pressure D is D2.
4. The charge level lowering method for blowing out the blast furnace according to claim 1, wherein in step S300, when the charge level is located in the furnace shell, the temperature T1 is 300 ℃ to 400 ℃, the working pressure S of spraying water is 1.2MPa, and the working pressure D of spraying nitrogen is 0.6 MPa; when the charge level is positioned at the waist of the furnace, the temperature T2 is 200-350 ℃, the working pressure S of spraying water is 1.2MPa, and the working pressure D of spraying nitrogen is 0.8 MPa; when the charge level is positioned at the furnace belly, the temperature T3 is 150-300 ℃, the working pressure S of water spraying is 1.2MPa, and the working pressure D of nitrogen spraying is 1.0 MPa; when the charge level is positioned in the hearth, the temperature T4 is 300-450 ℃, the working pressure S of water spraying is 1.2MPa, and the working pressure D of nitrogen spraying is 1.0 MPa.
5. The charge level lowering method according to claim 1, wherein in step S300, the blast air volume of the blast furnace is sequentially decreased as the charge level is lowered.
6. The charge level lowering method for blowing out a blast furnace according to claim 5, wherein the gas supplied during blowing comprises high temperature air and pure oxygen, and the amount of the pure oxygen supplied is sequentially decreased as the charge level is lowered.
7. The method for lowering the charge level in a blast furnace shutdown according to claim 6, wherein, in step S300,
when the charge level is positioned on the furnace body, the air supply volume is the air volume in a full-air full-oxygen state;
when the charge level is positioned at the furnace waist, the air supply volume is 60% -90% of the air volume in the full-air full-oxygen state, and the air supply volume is reduced by 1% -5% of the air volume in the full-air full-oxygen state every time the charge level is reduced by 0.2 m;
when the charge level is positioned in the furnace belly, the air supply volume is 30% -60% of the air volume in the full-air full-oxygen state, and the air supply volume is reduced by 1% -5% of the air volume in the full-air full-oxygen state every time the charge level is reduced by 0.2 m.
8. The charge level lowering method for blowing out a blast furnace according to claim 7, wherein in step S300, when the charge level is located in the furnace belly, the input of pure oxygen is stopped.
9. The charge level lowering method for blast furnace shutdown according to claim 1, wherein in step S300, during the lowering of the charge level, the gas in the throat is sampled and detected, and the sampling interval is t.
10. The charge level lowering method for blast furnace shutdown according to claim 1, wherein in step S300, steam is supplied to the throat during the charge level lowering phase of the blast furnace, and the pressure of the steam is greater than 0.4 MPa.
Priority Applications (1)
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| CN102782161A (en) * | 2010-03-02 | 2012-11-14 | 杰富意钢铁株式会社 | Blast furnace operation method, iron mill operation method, and method for utilizing a gas containing carbon oxides |
| CN103789473A (en) * | 2014-01-16 | 2014-05-14 | 宝钢集团新疆八一钢铁有限公司 | Water spraying device for blowing-out of blast furnace |
| CN109321699A (en) * | 2018-11-27 | 2019-02-12 | 南京钢铁股份有限公司 | A kind of method of the blast furnace stockline dropping blowing out not residual iron placing burn-up dead coke heap of tuyere area |
| CN110117683A (en) * | 2019-04-29 | 2019-08-13 | 柳州钢铁股份有限公司 | Stockline dropping is to air port novel environment friendly blowing out operating method |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102782161A (en) * | 2010-03-02 | 2012-11-14 | 杰富意钢铁株式会社 | Blast furnace operation method, iron mill operation method, and method for utilizing a gas containing carbon oxides |
| CN103789473A (en) * | 2014-01-16 | 2014-05-14 | 宝钢集团新疆八一钢铁有限公司 | Water spraying device for blowing-out of blast furnace |
| CN109321699A (en) * | 2018-11-27 | 2019-02-12 | 南京钢铁股份有限公司 | A kind of method of the blast furnace stockline dropping blowing out not residual iron placing burn-up dead coke heap of tuyere area |
| CN110117683A (en) * | 2019-04-29 | 2019-08-13 | 柳州钢铁股份有限公司 | Stockline dropping is to air port novel environment friendly blowing out operating method |
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