CN112176142A - Operation method for converting large and medium blast furnace from center coke feeding to center-free coke feeding - Google Patents
Operation method for converting large and medium blast furnace from center coke feeding to center-free coke feeding Download PDFInfo
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Abstract
An operation method for converting center coke feeding into center-free coke feeding of a large and medium-sized blast furnace belongs to the technical field of blast furnace iron-making operation. The technical scheme comprises the following procedures: (1) damping down: reducing the coke load, then adding a damping-down material to carry out damping-down operation, and reducing the stockline to be 4.0-6.0 m below the normal stockline when damping-down is finished; (2) adjusting the air port: determining the blast furnace air supply ratio after the central coke addition is cancelled, calculating the blast furnace air supply quantity according to the blast furnace air supply ratio, controlling the blast kinetic energy to be 75-160kw, and determining the blast area and the tuyere diameter of a blast furnace tuyere according to the blast energy; (3) charging: a material driving line operation is carried out by adopting a centerless coke feeding system; (4) and (5) re-air, and loading by adopting a centerless coke-feeding loading system. Is suitable for effective volume more than or equal to 1500m3The large and medium blast furnace utilizes short-term damping down, and a central coke charging system is converted into a non-central coke charging system under a static state, so that the difficulty of material system adjustment can be greatly reduced, and the stable and smooth conversion of the two systems can be stably realized.
Description
Technical Field
The invention relates to an operation method of a blast furnace, in particular to an operation method of a blast furnace for converting central coking into non-central coking of a large and medium-sized blast furnace, belonging to the technical field of blast furnace ironmaking operation.
Background
At present, large and medium blast furnaces (effective volume is more than or equal to 1500 m) adopting bell-less top equipment and using a multi-ring material distribution system3) The cloth mode mainly has two kinds, one kind has the center to add burnt, another kind does not have the center to add burnt. The purpose of central coke charging is to increase the proportion of coke in the central part of the blast furnace, reduce the resistance of furnace burden in the central part to blast furnace gas, and further reduce the phenomena that the descending speed of the furnace burden is slow, stagnation and the like are not beneficial to the smooth running of the blast furnace caused by the overhigh resistance of the furnace burden to the blast furnace gas, so as to realize the stable and high yield of the blast furnace. After the central coke charging and distributing, because the resistance of the furnace burden at the central part to the gas in the furnace is reduced, the flow velocity of the gas at the central part in the furnace is improved, the contact time of the gas and the furnace burden is shortened, and the quantity of iron oxide in the gas reduction furnace burden is reduced, so that the blast furnace with the central coke charging has the advantages of lower gas utilization rate, higher fuel ratio and poorer technical and economic indexes; the blast furnace without center coke feeding has high coal gas utilization rate, low fuel ratio and good technical and economic indexes. With the continuous improvement of the operation level of blast furnaces, a material distribution system without central coke feeding is adopted when the raw material conditions of most blast furnaces are improved, so that the technical and economic indexes of the blast furnaces are improved, and further, the stable production and the low consumption of the blast furnaces are realized. In actual production, when a plurality of large and medium blast furnaces change from a central coke feeding and distributing system to a non-central coke feeding and distributing system in the production process, the air flow in the furnacesThe furnace condition fluctuation such as slippage, material collapse and the like often occurs due to the disorder of the distribution, even the abnormality of the furnace condition seriously affects the stable production and low consumption of the blast furnace, the work is usually abandoned, and the blast furnace has to be returned to the original material preparation for central coking. Therefore, it is highly desirable to invent an operation method to realize the smooth transition of the material distribution system from the center coke feeding to the non-center coke feeding.
Disclosure of Invention
The present invention is to overcome the above problems in the prior art and to provide a method for converting a large or medium-sized blast furnace from center-charging to center-less-charging, so as to achieve stable and high yield of the blast furnace.
In order to solve the technical problems, the invention adopts the technical scheme that:
an operation method for converting a large and medium-sized blast furnace from center coking to center-less coking comprises the following steps:
(1) damping down: reducing the coke load, then adding a damping-down material to carry out damping-down operation, and reducing the stockline to be 4.0-6.0 m below the normal stockline when damping-down is finished;
(2) adjusting the air port:
a. firstly, determining the blast furnace air supply ratio:
blast furnace blast ratio of W/Vu
W-blast furnace blast air quantity in unit M3/m；
Vu-effective volume of blast furnace, unit M3；
The blast furnace air supply ratio is 0-0.15 lower than that in the state of central coking;
b. calculating to obtain blast furnace air quantity, controlling blast kinetic energy to be 75-160kw, determining area of a tuyere for blast furnace air supply, and further determining diameter of the tuyere;
(3) charging: a centerless coke feeding and charging system is adopted to carry out the material driving line operation, the material is driven to a normal material line before re-air, the size of an ore batch is 500-1000 mm when mineral materials are paved on the plane of the furnace throat, and the thickness of a material layer is 200-300 mm when coke is paved on the plane of the furnace waist; during material distribution, the total angle difference of ore is 6-10 degrees, and the total angle difference of coke is 6-13 degrees; the cloth gear of ore deposit is 3 ~ 6 keep off, and the cloth gear of burnt is 3 ~ 7 keep off. The number of turns of each grade of material distribution of the ore and the coke is 2-4;
(4) and (5) re-air, and loading by adopting a centerless coke-feeding loading system.
In the damping-down process, the coke load is reduced by 0.10-0.30 t/t on the basis of the coke load in a central coke feeding and distributing mode.
In the procedure of adjusting the tuyere, the blast furnace is a blast furnace without center coke feeding with stable furnace condition, the air supply ratio is lower by 0-0.15 compared with the blast furnace with the center coke feeding state, and the weighted length of the tuyere is 0-50 mm longer than the length of the tuyere with the center coke feeding state.
In the charging process, the number of the gear circles of the outer ring close to the furnace throat steel brick is not less than the number of the gear circles close to the center of the furnace throat; the distance between the blanking point corresponding to the maximum ore angle and the maximum coke angle distribution and the furnace throat steel brick is 200-700 mm; and the blanking point corresponding to the minimum ore angle and the minimum coke angle distribution is positioned between the furnace throat steel brick and the half of the radius of the furnace throat, and the blanking point of the minimum ore angle distribution is positioned between the blanking point of the minimum coke angle distribution and the furnace throat steel brick.
In the charging procedure, after a material driving line operation is carried out by adopting a centerless coke charging system, the shape of a charge level of an edge platform and a central funnel is formed at the throat, the width of the edge platform is 0.5-2.5 m, and the depth of the central funnel is 0.5-2.0 m;
in the secondary air process, in order to stabilize the furnace condition, 0-6 air ports are firstly blocked, air is supplied according to 30-70% of the blast furnace air supply quantity in the process (2), and after the furnace condition is stabilized, the residual air ports are gradually opened, and the air quantity is correspondingly increased to the normal blast furnace air supply quantity. After the air is re-blown, a non-center coke feeding system is adopted for feeding, and the feeding system is finely adjusted according to the furnace condition, so that a relatively stable non-center coke feeding reference feeding system is finally formed.
In the charging process, in the operation process of the material driving line, when the material line is 300mm smaller than the normal material line, the material is charged at the same time by reducing the material distribution angle of ore and coke by 1 degree, so that the furnace burden is prevented from colliding with the furnace wall, but the material distribution angle of the ore and coke is reduced by 3 degrees at most; when the stockline reaches 900mm below the normal stockline, the ore angle and the coke angle are simultaneously increased by 1 degree when the stockline rises by 300mm until the normal stockline and the distribution angle are recovered. .
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the operation of converting the central coking into the non-central coking is suitable for the effective volume of more than or equal to 1500m3The large and medium blast furnace realizes the conversion from a central coke feeding system to a non-central coke feeding system in a short-term damping-down state, and the maximum time can be finished within 4 hours. The static adjustment under the damping down condition can greatly reduce the difficulty of material preparation adjustment, and the operation of converting into the centerless coking can be completed in one step. The invention can effectively standardize the operation steps of converting the central coke feeding and distributing system of the large and medium-sized blast furnace to the non-central coke feeding and distributing system, stably and smoothly convert the two systems by damping down the blast furnace, and realize the stable yield and low consumption of the blast furnace. The condition that the coke is forced to return to the original center for coke feeding due to furnace condition fluctuation and even abnormality caused by the conversion of a material distribution system under the condition of air supply movement is avoided.
Detailed Description
The present invention will be described in further detail below with reference to specific examples.
Example 1: this example is 2500m3The operation method for converting the blast furnace from center coke feeding to center-free coke feeding is carried out by utilizing 2.5h short-term damping down according to the following procedures:
(1) damping down: on the basis of the coke load of a central coke feeding and distributing mode, the coke load is reduced by 0.15 t/t. The ore batch and the coke batch are 60 tons and 13 tons respectively when the blast furnace is normally produced and adopts central coke charging, and the load of the coke charged into the furnace is 4.6 t/t. In order to ensure that the blast furnace moves forward and realize the non-center coke feeding and distributing system without center coke feeding, the coke load of the charging materials is reduced to 4.45t/t before the blast furnace is shut down, namely the ore batch of light load materials is adjusted to 65 tons, the material layer thickness is 633mm when the ore materials are flatly paved on the furnace throat plane, the coke batch is 14.6 tons, and the coke layer thickness is 205mm when the coke is flatly paved on the furnace waist plane.
And (3) damping down operation, namely adding damping down materials according to a conventional blast furnace operation procedure and implementing the blast furnace damping down operation, wherein when damping down is finished, light-load furnace materials reach the upper edge of the furnace waist, and the material line is 5 m.
(2) Adjusting the air port: when the blast furnace is normally used for production and central coke charging, the blast furnace charging air quantity is 4900Nm3/min, and the air supply ratio is 1.96; blast furnace blast airThe number of the openings is 30, the diameter phi of the air opening is 125mm, and the air supply area is 0.3680m2The tuyere weighted length is 500 mm; determining that the blast furnace air supply ratio of a centerless coke charging and distributing system is 1.88 when the center coke charging is cancelled, and calculating to obtain the corresponding air quantity of 4700Nm3And/min. In order to ensure that the central air flow of the blast furnace is abundant and stable when the center-free coke-charging cloth is distributed, the air supply area is determined to be 0.3584m2Namely, the number of blast furnace air supply tuyeres is 30, and the diameter of the tuyeres is 10 multiplied by phi 120mm +20 multiplied by phi 125 mm; the length is 5 XL 500mm +25 XL 125mm, the tuyere weighted length thereof is increased to 516mm, and the tuyere is replaced.
(3) Charging:
when the blast furnace normally produces and adopts central coke feeding, the material distribution line of the blast furnace is 1.3m, and the central coke feeding and material distribution parameters are shown in a table 1:
TABLE 1 center coke addition distribution parameters
According to the calculation and actual measurement results of the blanking point and the corresponding distributing angle, the center-free coke-adding distributing parameters are determined to be shown in the table 2:
TABLE 2 center-less coke addition distribution parameters
As can be seen from the above table, the total angular difference of the ore is 8.5 degrees, and the total angular difference of the coke is 12.5 degrees; the distribution gears of the ore and the coke are all 5 gears, the number of the distribution turns of the ore at the 1-2 gears is 4, the number of the distribution turns of the ore at the 3-4 gears is 3, and the number of the distribution turns of the ore at the 5 gears is 2; the cloth turns of coke at 1-3 gears are 3 turns, and the cloth turns of coke at 4-5 gears are 2 turns.
When the material distribution angle of the ore at 1 position is 41 degrees, the blanking point is 530mm away from the throat steel brick; the blanking point of coke is 250mm away from the furnace throat steel brick when the material distribution angle of coke at 1 position is 41 degrees. When the material distribution angle of the ore at 5 gears is 32.5 degrees, the blanking point is positioned between one half of the radius of the furnace throat and the steel brick at the furnace throat and is 1650mm away from the steel brick at the furnace throat, and when the material distribution angle of the coke at 5 gears is 28.5 degrees, the blanking point is positioned between one half of the radius of the furnace throat and the steel brick at the furnace throat and is 1930mm away from the steel brick at the furnace throat.
During the damping down, the material distributing system and the light-load material distributing line are adopted, the first batch of materials of the material distributing line start to simultaneously retreat at the ore and coke distributing angles by 3 degrees, when the material line is driven to 1.9m and 1.6m, the ore and coke distributing angles are respectively simultaneously lifted by 1 degree, and when the normal material line of 1.3m is reached, the normal distributing angle is recovered, at the moment, the shape of the throat material surface of the furnace is the shape of an edge platform plus a central funnel, the width of the platform is 0.95m, and the depth of the funnel is 1.0 m.
(4) Wind recovery:
the number 5, 12, 19 and 27 are blocked before the air recovery, and the air recovery starting air quantity is 2500Nm3And/min. The air quantity is 3500-3600 Nm at the initial stage of air recovery3And at the time of/min, the temperature of the central gas is 400-450 ℃, the temperature of the edge gas flow is 120-140 ℃, and the central gas flow is weaker. And the material distribution operation of a small ore angle gear of 32.5 degrees is cancelled in the 9 th batch after air supply. Then, under the combined action of cloth adjustment and air adding, the temperature of the central gas is gradually increased to 550-550 ℃, and the temperature of the edge gas flow is decreased to 90-100 ℃. The 18 th batch recovered a notch and lap distribution at a small mine angle of 32.5 deg. as the core air flow became stronger. The stability of furnace condition is better, and the air quantity is increased to 4100Nm3After/min, maintaining for 30 min, poking 5 # and 19 # 2 air ports, and further adding the air quantity to 4400m3Min, stabilizing for 40 minutes, and finally poking the rest No. 12 and No. 27 air ports to realize air supply of full-open air ports, wherein the air quantity is increased to 4700m3And/min. After that, the material preparation was finely adjusted and aligned again within a period of about 10 days according to the furnace condition reaction and the gas flow change. Through fine adjustment, the furnace condition and the air flow of the blast furnace become more stable, and finally, a reference material system for the centerless coking of the blast furnace is formed. Therefore, the central coke feeding is successfully cancelled, and the smooth transition from the central coke feeding to the non-central coke feeding cloth system is smoothly realized. Reference material parts determined for center-less coke addition table 3:
TABLE 3 center-less coking reference cloth parameters
The material system adjustment is mainly to fix a reference material system and finely adjust the material line, the adjustment range of the material line is controlled to be 1.3 +/-0.3 m, and if the adjustment range is within the range, the effect of adjusting the material line is not obvious, and the adjustment circle number and the adjustment angle are considered. The standard material is not fixed, is kept relatively fixed only within a certain period of time, and is also properly adjusted along with the change of the cloth conditions. Selecting the size of the ore batch according to the large effective volume of the blast furnace, taking an upper limit value, and otherwise, taking a lower limit value; the coke batch size can be taken in the same way.
Example 2: this example is 1780m3The operation method for converting the blast furnace from center coke feeding to center-free coke feeding is carried out by using a short-term damping-down of 3.0h according to the following procedures:
(1) damping down: on the basis of the coke load of a central coke feeding and distributing mode, the coke load is reduced by 0.30 t/t. The ore batch when the blast furnace is normally produced and adopts central coke charging is 45 tons, and the coke charging load of the blast furnace is 4.83 t/t. In order to ensure that the blast furnace moves forward and realize the non-center coke feeding and distributing system without center coke feeding, the coke load of the charging materials is reduced to 4.53t/t before the blast furnace is shut down, namely the ore batch of light load materials is adjusted to 48 tons, the material layer thickness is 675mm when the ore materials are flatly paved on the furnace throat plane, the coke batch is 10.6 tons, and the coke layer thickness is 227mm when the coke is flatly paved on the furnace waist plane.
And (3) damping down operation, namely adding damping down materials according to a conventional blast furnace operation procedure and implementing the blast furnace damping down operation, wherein when damping down is finished, light-load furnace materials reach the upper edge of the furnace waist, and the stockline is 4 m.
(2) Adjusting the air port: when the blast furnace is normally used for production and central coke charging, the blast furnace charging air quantity is 3600Nm3/min, and the air supply ratio is 2.02; the number of blast furnace air supply tuyeres is 24, the diameter of the tuyere is 20 multiplied by phi 120mm +4 multiplied by phi 125mm, and the air supply area is 0.2751m2The tuyere weighted length is 488 mm; determining that the blast furnace air supply ratio of the centerless coke charging and distributing system is 1.97 by canceling center coke charging, and calculating to obtain the corresponding air quantity of 3500Nm3And/min. To ensure no-center coke-adding clothThe air flow of the center of the blast furnace is abundant and stable during charging, and the air supply area is determined to be 0.2713m2Namely, the number of blast furnace air supply tuyeres is 24, and the diameter of the tuyeres is 24 multiplied by phi 120 mm; the length is 24 xl 120mm, the tuyere weighted length thereof is increased to 500mm, and the tuyere is replaced.
(3) Charging:
when the blast furnace normally produces and adopts center coke feeding, the material distribution line of the blast furnace is 1.6m, and the material distribution parameters of the center coke feeding are as shown in the table 4:
TABLE 4 center coke addition distribution parameters
According to the calculation and actual measurement results of the blanking point and the corresponding distributing angle, determining a non-center coke-adding distributing parameter piece table 5:
TABLE 5 center-less scorch distribution parameters
As can be seen from the above table, the total angular difference of the ore is 8 degrees, and the total angular difference of the coke is 11 degrees; the distribution gear of the ore is 5 gears, the distribution coil number of the ore at 1 gear is 4 coils, the distribution coil number of the ore at 2 and 3 gears is 3 coils, the distribution coil number of the ore at 4 gears is 2 coils, and the distribution coil number of the ore at 5 gears is 1 coil; the cloth gear of burnt is 5 grades, and burnt cloth number of turns at 1 ~ 3 gears is 3 rings, is 2 rings at 4 grades of cloth number of turns and 5 grades of cloth number of turns.
When the material distribution angle of the ore at 1 position is 36.5 degrees, the blanking point is 550mm away from the furnace throat steel brick; the blanking point of coke is 300mm away from the furnace throat steel brick when the material distribution angle of coke at 1 position is 37 degrees. When the material distribution angle of the ore at 5 gears is 28.5 degrees, the blanking point is positioned between the half part of the furnace throat radius and the furnace throat steel brick and is 1550mm away from the furnace throat steel brick, and when the material distribution angle of the coke at 5 gears is 26 degrees, the blanking point is positioned between the half part of the furnace throat radius and the furnace throat steel brick and is 1600mm away from the furnace throat steel brick.
During the damping down, the material distributing system and the light-load material distributing line are adopted, the first batch of materials of the material distributing line start to synchronously retreat at the ore and coke distributing angles by 3 degrees, when the material line is driven to 2.0m, the ore and coke distributing angles are respectively and simultaneously lifted by 3 degrees, and when the normal material line of 1.6m is reached, the normal distributing angle is recovered, at the moment, the shape of the charge surface of the furnace throat is the shape of an edge platform plus a central funnel, the width of the platform is 2.5m, and the depth of the funnel is 0.5m when the furnace throat is observed from a manhole of the.
(4) Wind recovery:
the number 1 and the number 13 are blocked before the return air, the total number of 2 air ports are blocked, and the starting air quantity of the return air is 2000Nm3Min, restoring the air quantity to 3200Nm3Min, poking No. 1 air port according to furnace conditions, adding air to 3350Nm3And/min. At the moment, the stability of the furnace condition is better, the central air flow is narrow and stable, but the edge air flow is unstable according to the judgment of furnace top imaging and furnace body static pressure analysis. Accordingly, the ore burden distribution angle is raised by 0.5 °. After adjustment, not only the edge flow is stabilized, but also the center flow is enhanced. Then according to the furnace condition, poking the rest No. 13 air ports and adding the air quantity to 3500m3And/min, smoothly realizing the stable transition of a material distribution system from central coke feeding to non-central coke feeding.
Example 3: this example is 3200m3The operation method for converting the blast furnace from center coke feeding to center-free coke feeding is carried out by utilizing 1.0h short-term damping down according to the following procedures:
(1) damping down: on the basis of the coke load of a central coke feeding and distributing mode, the coke load is reduced by 0.10 t/t. The ore batch and the coke batch are 96 tons and 21.3 tons respectively when the blast furnace is normally produced and adopts central coke charging, and the load of the coke charged into the furnace is 4.5 t/t. In order to ensure that the blast furnace moves forward and realize the non-center coke feeding and distributing system without center coke feeding, the coke load of the charging materials is reduced to 4.30t/t before the blast furnace is stopped, namely the ore batch of light load materials is adjusted to 90 tons, the material layer thickness is 745mm when the ore materials are paved on the furnace throat plane, the coke batch is 20.9 tons, and the coke layer thickness is 280mm when the coke is paved on the furnace waist plane.
And (3) damping down operation, namely adding damping down materials according to a conventional blast furnace operation procedure and implementing the blast furnace damping down operation, wherein when damping down is finished, light-load furnace materials reach the upper edge of the furnace waist, and the stockline is 6 m.
(2) Adjusting the air port: the blast furnace inlet air quantity is 6100Nm when the blast furnace normally produces and adopts the center coke charging3Min, the air supply ratio is 1.91;the number of blast furnace air supply tuyeres is 32, the diameter of the tuyeres is 32 multiplied by phi 130mm, and the air supply area is 0.4245m2The weighting length of the tuyere is 570 mm; determining that the blast ratio of the blast furnace to realize the centerless coke charging and distributing system without the center coke charging is 1.81, and calculating to obtain the corresponding blast volume of 5800Nm3And/min. In order to ensure that the central air flow of the blast furnace is abundant and stable when the center-free coke-charging cloth is distributed, the air supply area is determined to be 0.4049m2Namely, the number of blast furnace air supply tuyeres is 32, and the diameter of the tuyeres is 22 multiplied by phi 130mm +10 multiplied by phi 120 mm; the length of the tuyere is 10 xL 600mm +22 xL 580mm, the weighted length of the tuyere is increased to 586mm, and the tuyere is replaced.
(3) Charging:
when the blast furnace normally produces and adopts center coke feeding, the material distribution line of the blast furnace is 1.4m, and the material distribution parameters of the center coke feeding are as shown in the table 6:
TABLE 6 center coke addition distribution parameters
According to the calculation and actual measurement results of the blanking point and the corresponding distributing angle, determining a center-free coke-adding distributing parameter piece table 7:
TABLE 7 center-less coke addition distribution parameters
As can be seen from the above table, the total angular difference of the ore is 8 degrees, and the total angular difference of the coke is 12 degrees; the distribution gears of the ore and the coke are respectively 5 and 6. The number of turns of the material distribution of the ore at 1-2 gears is 4, the number of turns of the material distribution at 3-4 gears is 3, and the number of turns of the material distribution at 5 gears is 2; the number of cloth turns of coke at 1-3 gears is 3, the number of cloth turns at 4-5 gears is 2, and the number of cloth turns at 6 gears is 3.
When the material distribution angle of the ore at 1 position is 45 degrees, the blanking point is 200mm away from the furnace throat steel brick; the blanking point of the coke is 280mm from the furnace throat steel brick when the material distribution angle of the coke at 1 position is 45 degrees. When the material distribution angle of the ore at 5 gears is 37 degrees, the blanking point is positioned between the half part of the furnace throat radius and the furnace throat steel brick and is 1700mm away from the furnace throat steel brick, and when the material distribution angle of the coke at 6 gears is 33 degrees, the blanking point is positioned between the half part of the furnace throat radius and the furnace throat steel brick and is 2200mm away from the furnace throat steel brick.
During the damping down, the material distributing system and the light-load material distributing line are adopted, the first batch of materials of the material distributing line start to simultaneously retreat at the ore and coke distributing angles by 3 degrees, when the material line is driven to 1.9m, the ore and coke distributing angles are respectively simultaneously lifted by 3 degrees, and when the normal material line of 1.4m is reached, the normal distributing angle is recovered, at the moment, the shape of the throat material surface of the furnace is an edge platform plus a central funnel shape, the platform width is 0.5m, and the funnel depth is 2.0 m.
(4) Wind recovery:
6 air ports 1, 6, 11, 16, 21 and 27 are uniformly distributed and blocked before air recovery. 3000Nm of composite wind starting wind volume3Min, the air quantity is recovered to 4700Nm3/min, No. 1 and No. 16 air ports are poked open, the air quantity is added to 5100m3Min, poking No. 6 and No. 21 2 air ports, and adding the air quantity to 5400m3Min, poking 11-numbered and 27-numbered 2 air ports, blowing air from all the air ports, and adding the air quantity to 5800m3And/min. After the central coke feeding is cancelled, the furnace condition is stable and smooth, the coal gas utilization rate is improved by 3 percent compared with that during the central coke feeding, and the fuel ratio is reduced by 15 kg/t.
The blast furnace uses the non-center coke feeding material as a reference material, the ore coke platform is adjusted and stabilized daily, the material line is adjusted finely to balance two air flows at the edge and the center, and the adjustment range of the material line is controlled within 1.4 +/-0.3 m.
Example 4: this embodiment is 3600m3The operation method for converting the blast furnace from center coke feeding to center-free coke feeding is carried out by using a short-term damping-down of 3.0h according to the following procedures:
(1) damping down: on the basis of the coke load of a central coke feeding and distributing mode, the coke load is reduced by 0.33 t/t. The batch of ore normally produced by the blast furnace and using center coke charging was 105 tons, and the coke charge to the furnace was 4.83 t/t. In order to ensure that the blast furnace moves forward and realize the non-center coke feeding and distributing system without center coke feeding, the coke load of the charging materials is reduced to 4.50t/t before the blast furnace is shut down, namely the ore batch of light load materials is adjusted to 95 t, the material layer thickness is 736mm when the ore materials are flatly paved on the furnace throat plane, the coke batch is 21.1 t, and the coke layer thickness is 267mm when the coke is flatly paved on the furnace waist plane.
Damping-down operation the damping-down material is added and the damping-down operation of the blast furnace is implemented according to the conventional blast furnace operation procedures, when the damping-down operation is finished, the light load furnace burden reaches the upper edge of the furnace waist, and the stockline is 4.8 m.
(2) Adjusting the air port: the blast furnace is normally produced and the furnace inlet air quantity of the blast furnace is 6200Nm when the center coke is added3Min, the air supply ratio is 1.72; the number of blast furnace air supply tuyeres is 32, the diameter of the tuyeres is 32 multiplied by phi 130mm, and the air supply area is 0.4245m2The weighting length of the tuyere is 600 mm; determining that the blast ratio of the blast furnace to realize the centerless coke charging and distributing system is 1.67 without the center coke charging, and calculating to obtain the corresponding blast volume of 6000Nm3And/min. In order to ensure that the central air flow of the blast furnace is abundant and stable when the center-free coke-charging cloth is distributed, the air supply area is determined to be 0.4088m2Namely, the number of blast furnace air supply tuyeres is 32, and the diameter of the tuyeres is 24 multiplied by phi 130mm +8 multiplied by phi 130 mm; the length of the tuyere is 16 XL 600mm +16 XL 620mm, the weight length of the tuyere is increased to 610mm, and the tuyere is replaced.
(3) Charging:
when the blast furnace normally produces and adopts center coke feeding, the material distribution line of the blast furnace is 1.5m, and the center coke feeding and material distribution parameter part is shown in table 8:
TABLE 8 center coke addition distribution parameters
According to the calculation and actual measurement results of the blanking point and the corresponding distributing angle, determining a no-center coke-adding distributing parameter table 9:
TABLE 9 centreless scorching distribution parameters
As can be seen from the above table, the total angular difference of the ore is 8 degrees, and the total angular difference of the coke is 11 degrees; the distribution gear of the ore is 5 gears, the number of distribution turns of the ore at 1-3 gears is 3 turns, and the number of distribution turns of the ore at 4-5 gears is 2 turns; the cloth gear of burnt is 6 keeps off, and burnt cloth number of turns at 1 ~ 3 gears is 3 rings, is 2 rings at the cloth number of turns of 4 ~ 6 gears.
When the material distribution angle of the ore at 1 position is 43 degrees, the blanking point is 450mm away from the furnace throat steel brick; the blanking point of coke is 300mm away from the furnace throat steel brick when the material distribution angle of coke at 1 position is 43 degrees. When the material distribution angle of ore at 5 gears is 35 degrees, the blanking point is positioned between one half of the furnace throat radius and the furnace throat steel brick and is 1900mm away from the furnace throat steel brick, when the material distribution angle of coke at 6 gears is 32 degrees, the blanking point is positioned between one half of the furnace throat radius and the furnace throat steel brick and is 2300mm away from the furnace throat steel brick
During the damping down, the material distributing system and the light-load material distributing line are adopted, the first batch of materials of the material distributing line start to synchronously retreat at an ore and coke distributing angle by 3 degrees, when the material line is driven to 2.0m and 1.7m, the ore and coke distributing angle is respectively and simultaneously lifted by 1 degree, and when the normal material line of 1.5m is reached, the normal distributing angle is recovered, at the moment, the shape of the throat charge surface is the shape of an edge platform and a central funnel, the width of the platform is 0.7m, and the depth of the funnel is 1.2m when the furnace top manhole observes.
(4) Wind recovery:
the number 2, 13 and 24 are blocked before the air recovery, and the air recovery starting air quantity is 3000Nm3And/min. The air quantity is recovered to 5400Nm3After min, according to the stability of furnace condition, poking 2 or 24 air ports, adding air to 5800Nm3And/min. After the air is added into the poking air opening, the furnace condition is generally smooth, but the pressure of the hot air is slightly fluctuated. And (4) according to furnace top cross temperature measurement, furnace top imaging and furnace body static pressure analysis, judging the stability deviation of the blast furnace edge airflow. Accordingly, the distribution angle of the ore and the coke is raised by 0.5 degrees. After adjustment, not only edge gas flow is stabilized, but also central gas flow is enhanced, and the stability of the furnace condition is improved. Then poking the rest of the air ports, and adding the air quantity to 6000m3And/min, smoothly realizing the stable transition of a material distribution system from central coke feeding to non-central coke feeding. After the material preparation adjustment is successful, the furnace condition keeps long-term stable and smooth, and then the standard material part without center coke addition is determined as shown in the table 10:
TABLE 10 centerless coking reference Material distribution parameters
The material system adjustment is mainly to fix the reference material system and finely adjust the material line, and the adjustment range of the material line is controlled to be 1.5 +/-0.3 m.
Claims (7)
1. An operation method for converting a large and medium-sized blast furnace from center coking to center-less coking is characterized by comprising the following steps of:
(1) damping down: reducing the coke load, then adding a damping-down material to carry out damping-down operation, and reducing the stockline to be 4.0-6.0 m below the normal stockline when damping-down is finished;
(2) adjusting the air port:
a. firstly, determining the blast furnace air supply ratio:
blast furnace blast ratio = W/Vu
W-blast furnace blast air quantity in unit M3/m ；
Vu-effective volume of blast furnace, unit M3 ；
The blast furnace air supply ratio is 0-0.15 lower than that in the state of central coking;
b. calculating to obtain blast furnace air quantity, controlling blast kinetic energy to be 75-160kw, determining area of a tuyere for blast furnace air supply, and further determining diameter of the tuyere;
(3) charging: a material driving line operation is carried out by adopting a centerless coke feeding and charging system, and the material is driven to a normal material line before air supply; the size of the ore batch is 500-1000 mm when the ore material is paved on the furnace throat plane, and the size of the coke batch is 200-300 mm when the coke is paved on the furnace waist plane; during material distribution, the total angle difference of ore is 6-10 degrees, and the total angle difference of coke is 6-13 degrees; the distribution gear of the ore is 3-6 gears, the distribution gear of the coke is 3-7 gears, and the number of turns of the distribution of each gear of the ore and the coke is 2-4 turns;
(4) and (5) re-air, and loading by adopting a centerless coke-feeding loading system.
2. The operating method for converting the center-charging into the centerless-charging of the large and medium-sized blast furnace according to claim 1, wherein the coke load in the damping-down process is reduced by 0.10 to 0.30t/t based on the coke load in the center-charging distribution manner.
3. The method of claim 1, wherein the tuyere adjusting step is performed such that the blast furnace without center-charging has a blast ratio lower by 0 to 0.15 than that in the state with center-charging and a tuyere weight length longer by 0 to 50mm than that in the state with center-charging.
4. The operating method for converting the large and medium-sized blast furnace from the center coke feeding to the center-less coke feeding according to claim 1, 2 or 3, wherein in the charging process, the number of shift turns of the outer ring near the throat steel bricks is not less than the number of shift turns near the center of the throat; the distance between the blanking point corresponding to the maximum ore angle and the maximum coke angle distribution and the furnace throat steel brick is 200-700 mm; and the blanking point corresponding to the minimum ore angle and the minimum coke angle distribution is positioned between the furnace throat steel brick and the half of the radius of the furnace throat, and the blanking point of the minimum ore angle distribution is positioned between the blanking point of the minimum coke angle distribution and the furnace throat steel brick.
5. The operating method for converting a center-charging mode into a center-less-charging mode in the large and medium-sized blast furnace according to claim 4, wherein in the charging step, after a material-removing line operation is performed by using a center-less-charging system, the shape of the charge level of the edge platform + the center hopper is formed at the throat, the width of the edge platform is 0.5 to 2.5m, and the depth of the center hopper is 0.5 to 2.0 m.
6. The operating method for converting the center-coking into the center-less-coking of the large and medium-sized blast furnaces according to claim 1, 2 or 3, characterized in that in the secondary air process, 0-6 air ports are blocked, 30-70% of air supply of blast furnace air supply amount in the air port process is adjusted according to the (2), and after the furnace conditions are stable, the rest air ports are opened gradually and the air amount is increased correspondingly to the normal blast furnace air supply amount.
7. The operating method for converting a large-medium sized blast furnace from center charging to centerless charging according to claim 5, wherein during the operation of the material driving line, when the material line is 300mm smaller than the normal material line, the charging is performed by reducing the material distributing angle of ore and coke by 1 degree at the same time, so as to prevent the charging from colliding with the furnace wall, but the material distributing angle of ore and coke is reduced by 3 degrees at most at the same time; when the stockline reaches 900mm below the normal stockline, the ore angle and the coke angle are simultaneously increased by 1 degree when the stockline rises by 300mm until the normal stockline and the distribution angle are recovered.
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