JP3787238B2 - Charging method into the center of the blast furnace - Google Patents

Description

【００４２】
実施番号１〜７は装入パターン▲１▼、▲２▼について実施したものであり、実施番号８〜１１についてはコークスの粒度および低反応性コークスの使用等について実施した。なお、実施番号１２については比較のために従来例を挙げた。
表１から明らかなように、本発明によれば良好な融着帯が従来例に比して安定して得られた結果、高炉操業が安定し、かつ高出銑比を確保することができた。
【００４３】
【発明の効果】
以上説明したように、本発明装入方法を実施することにより、コークスを炉半径方向でその分布を適正かつ確実に形成させることができ、適切な高炉内融着帯形状を安定して得ることが可能となり、適正な高炉中心ガス流を確保すると共に、炉円周方向にも安定した周辺ガス流を形成させることができる。
【図面の簡単な説明】
【図１】本発明による高炉への装入物の装入初期の状態を示した図。
【図２】本発明の装入方法によって得られた装入物の装入層の状態を示した図。
【図３】高炉内での逆Ｖ型融着帯の例を示した図。
【図４】通常の高炉装入における鉄鉱石層とコークス層の形状を示した図。
【図５】炉中心部の上昇ガス流が大きい場合の炉中心部の装入コークスの状態を模式的に示した図。
【図６】炉頂ホッパーでの装入物の貯留状態を示した図。
【図７】ベルレス高炉における高炉半径方向でのガス利用率（ηＣＯ）の分布状態を示した図。[0001]
BACKGROUND OF THE INVENTION
The present invention forms a cohesive zone that is stable against changes in the quality of pig iron produced by the blast furnace and the situation inside the furnace accompanying fluctuations in production volume, and has a cohesive zone shape for smooth blast furnace operation. The present invention relates to a charging method for charging a blast furnace center suitable for forming.
[0002]
[Prior art]
There are two main control means in the blast furnace: charge distribution control and air blow control. The airflow control determines the raceway conditions (raceway shape, raceway temperature distribution, raceway gas composition distribution, etc.), but the charge distribution control controls the gas flow distribution and melting that influence the reaction heat transfer in the blast furnace. Since it is the only means of determining the shape of the banding, it is the most commonly used and most important control means.
[0003]
In general, a blast furnace is charged with iron ore, sintered ore, pellets (hereinafter simply referred to as iron ore) and coke from the top of the blast furnace furnace, and from the blower tuyere (hereinafter simply referred to as tuyere) at the bottom of the furnace. It is operating with hot air. In the blast furnace, the iron ore is heated-reduced (indirect reduction) -melted while descending in the furnace with high-temperature furnace gas containing CO gas generated by the reaction between coke and hot air at the tip of the tuyere.
Furthermore, the molten iron ore is collected in the hot water reservoir while being reduced (direct reduction) with coke present in the dropping zone during dripping, and is discharged out of the furnace through the tap at an appropriate time. This iron ore is in a softened and fused state (hereinafter simply referred to as a fused zone) immediately before being melted and dripped, and exists in the furnace with coke interposed therebetween.
[0004]
Thus, in the blast furnace, there is a lump band portion in which the charged iron ore is in a lump state, a fusion band in a softened and fused state, a dripping band portion in a molten dripping state, The gas in the furnace is discharged from the tip of the tuyere through the dripping band, the fusion band, and the massive band in order. The air resistance of these three members is the largest in the cohesive zone, followed by the massive band portion, and the dropping band portion is the smallest. Therefore, the shape of the massive band portion and the dripping band portion is different depending on the shape of the fusion band, and the air permeability and gas utilization rate in the furnace are different.
[0005]
For example, in the so-called central flow type cohesive zone (reverse V type) in which the top of the cohesive zone is high, the massive belt portion is narrowed, while the dripping zone is widened, so that the air permeability is good and at the same time Since the gas always flows through the core and the gas flow is stabilized, the gas utilization rate can be maintained at a high level.
In addition, in the so-called flat type cohesive zone where the top of the cohesive zone is lowered, the massive belt portion is widened, but since the dripping zone is narrowed, the air permeability is deteriorated and at the same time, the gas in the furnace may drift. Yes, the gas utilization rate may decrease.
This air permeability and gas utilization rate are closely related to productivity and fuel ratio. If the position and shape of the cohesive zone are detected during blast furnace operation, and the cohesive zone is optimally controlled, the ventilation Efficiency and gas utilization can be adjusted, and productivity can be increased and fuel ratio can be reduced.
[0006]
Several inventions have been disclosed as a method for controlling the cohesive zone in such a blast furnace. For example, according to the technique presented in Japanese Examined Patent Publication No. 63-61367, One or more sondes are inserted into the furnace from the lower part, and the upper and lower positions of the cohesive zone are determined from the measured gas body and solid temperature obtained from the sonde, and the measured gas composition, It is characterized by controlling the distribution of iron ore layer thickness to coke layer thickness (O / C) and particle size distribution in the radial direction of the blast furnace so that the position of the cohesive zone occupies the optimum position for blast furnace operation Yes.
[0007]
That is, it is said that an appropriate cohesive zone can be obtained by controlling the distribution of O / C of iron ore and coke charged into the blast furnace as the control of the cohesive zone. Has a smaller particle diameter and layer space ratio than the coke layer, so the gas permeability is poor in the part where the iron ore layer thickness is relatively thick in the radial direction of the blast furnace, so the gas flow velocity flowing through that part, The gas flow rate decreases. A decrease in the gas flow rate affects various aspects, and with regard to heat transfer, it causes a decrease in the amount of sensible heat of gas flowing through the unit cross-sectional area and a deterioration in heat transfer to the solid substance. Regarding the reaction, since the gas amount sufficient to reduce the iron ore is not supplied, the concentration of the reducing gas is lowered, and the reduction driving force is weakened, resulting in a relative reduction in the reduction rate.
[0008]
From the above, a portion having a high O / C in the radial direction causes a reduction in reduction rate and a reduction in gas body and solid temperature.
Therefore, for example, in order to realize a high cohesive zone at the center, it is necessary to supply sufficient heat to the center at the bottom of the furnace. For this purpose, it is necessary to increase the gas supply to the furnace center, that is, to reduce the O / C at the center, and to achieve a high cohesive zone at the periphery, for the same reason, It is stated that an operation for reducing the O / C in the peripheral portion is necessary.
[0009]
However, according to the conventional method of charging the blast furnace charge in the conventional method, for example, as shown in FIG. 4, when the coke (C) and iron ore (O) are sequentially charged in layers, The tendency of the iron ore charge layer to be thick and the coke charge layer to be thin could not be avoided.
This is because the angle of repose of iron ore is smaller than the angle of repose of coke, and the bulk density of iron ore and coke is greatly different, resulting in a phenomenon that the iron ore layer is inevitably thickened in the center of the momentum furnace. Therefore, the flow of gas supplied from the lower part of the furnace at the furnace center becomes poor in air permeability in the thick part of the iron ore layer at the furnace center, and as a result, the gas flows to the furnace peripheral part where the gas flow is relatively easy. It will flow across that part.
[0010]
For example, there is a technique in which coke is charged only in the center of the blast furnace by a special means against such a distribution state of the charge, and the chimney-like coke accumulation state is actively maintained in the center of the furnace. This is disclosed in Japanese Patent Publication No. 6-37649.
If the technology described in this publication is applied to blast furnace operation, a chimney of coke should be able to be easily made in the center of the furnace. In the coke layer, the air permeability is excessive, the upward gas flow from the downward direction is too strong, and the coke that is to be deposited in the chimney form is blown up. As shown schematically in FIG. It is considered that the effect of charging the central portion of the coke is actually surprisingly small.
[0011]
[Problems to be solved by the invention]
As described above, an appropriate shape of the cohesive zone is known. For example, as shown in FIG. It is an ideal shape. In order to obtain this shape, as described above, it is necessary to reduce the O / C at the center of the furnace. In other words, there is a method for charging the charge so that the amount of coke at the center of the furnace is as large as possible. It is preferable.
[0012]
Under such circumstances, it is suitable for obtaining the distribution state of the charge distribution in the actual blast furnace (iron ore, coke, etc.), that is, the distribution state of appropriate O / C in the blast furnace radial direction. Charging equipment is required. However, in the bell-less blast furnace, if the above adjustment is to be carried out, it is necessary to move the tilt angle of the swivel chute over a wide range. Therefore, under high operating conditions, the charge is placed in the furnace. There was a problem that it took too long to charge, and there was a situation where a desired O / C distribution could not be made in the blast furnace radial direction.
[0013]
In addition, as mentioned above, the coke charging to the furnace center is affected by the gas flow rising up the furnace center, so if you do not adopt an appropriate charging method after considering the countermeasures, Therefore, after summarizing these points, it is possible to obtain the O / C distribution state in the blast furnace radial direction as described above simply and easily using conventional charging equipment. There was a strong demand for development of technology.
[0014]
[Means for Solving the Problems]
The present invention has been made to solve the problems in the conventional methods described above, and the gist of the present invention resides in the following means.
(1) In order to deposit coke and iron ore alternately in layers in the bell-less blast furnace , when charging the charge into the blast furnace , the coke and iron ore are sequentially charged, and the iron ore is charged immediately before the iron ore via a turning chute. In charging the final coke, the tilt angle of the turning chute is set to a specific angle within a range of 20 to 35 °, and then the final coke is charged into a predetermined position in the blast furnace radial direction , Charging in the shape of a dam and then charging the iron ore between the outside of the final coke deposit and the blast furnace wall with the swivel chute Law .
(2) In order to deposit coke and iron ore alternately in layers in the bell-less blast furnace , when charging the coke and iron ore into the blast furnace, the charge is charged immediately before the iron ore via a turning chute. In charging the final coke, the coke is introduced into the lower part of the furnace hopper directly above the blast furnace, and then iron ore is introduced into the upper part thereof, and the coke and iron ore are stored in layers in the furnace hopper. Thereafter, the tilt angle of the swivel chute is set to a specific angle within a range of 20 to 35 °, and then the shut-off valve is opened, and most of the lower storage coke is used as the final coke charged immediately before the iron ore . Charging into a predetermined position in the radial direction of the furnace mouth and depositing it in a weir shape , then moving the swivel chute to the outside of the final coke deposit and starting the charging of the upper stored iron ore. Charging method to the center of the blast furnace.
[0015]
(3) The iron ore charging after the final coke charging is performed in order from the outer side of the coke deposit part toward the blast furnace wall side in order to activate the blast furnace core part according to (1) or (2). Charging method for charging.
(4) The blast furnace according to any one of (1) to (3), wherein the final coke charged and deposited at a predetermined position in the radial direction of the blast furnace is charged into the blast furnace with a large particle size. To charge the furnace core in
(5) The final coke charged and deposited at a predetermined position in the blast furnace radial direction of the blast furnace is charged into any one of (1) to (4) by changing its reactivity to low reactivity. The charging method to the furnace center part in the described blast furnace.
[0016]
(6) The final coke charged and deposited at a predetermined position in the blast furnace radial direction of the blast furnace is adjusted and controlled by adjusting the coke charging ratio (1 / n) according to the gas utilization rate in the furnace radial direction at the top of the blast furnace. (1) to (5), the method of charging a charge into the furnace center in the blast furnace according to any one of (1) to (5).
The coke charging ratio (1 / n) is, for example, (C ↓ O ↓), (C ↓ C ↓ O ↓ O ↓), (C ↓ C ↓ C ↓ O ↓ O ↓), etc. When the charge of coke (C) and iron ore (O) in which the form exists is one charge, it means the number of coke charges with respect to the number of charge charges (n).
[0017]
(7) In the above (6), when the gas utilization rate (ηCO) exceeds 20% in the center of the furnace, the coke charging ratio of the final coke charged to a predetermined position in the blast furnace radial direction ( 1 / n) The charging method of charging into the furnace center in the blast furnace.
(8) In the above (6), when the gas utilization rate (ηCO) value satisfies 20% or less in the center of the furnace and the value of ηCO in the furnace middle part becomes 60% or more, A charging method for charging a furnace center portion in a blast furnace to reduce a coke charging ratio (1 / n) of a final coke charged to a predetermined position in a mouth radial direction.
(9) When a state where the gas utilization rate (ηCO) deviates from the value set in (7) or (8) has passed for at least 8 hours, the gas utilization rate (ηCO) is charged into a predetermined position in the blast furnace radial direction. A charging method for charging a furnace into the center of a blast furnace in which the coke charging ratio (1 / n) of the final coke is increased or decreased.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
When the present inventors considered the charging state of the charge in the blast furnace, as described above, the coke charged in the center of the blast furnace has a low specific gravity and a low bulk density, so that it rises from the lower part of the furnace. Because it is blown up and scattered by the gas flow, iron ore with heavy specific gravity flows into the gap (iron ore is easy because the angle of repose is small), and it is a lot difficult to obtain the desired coke deposit in the furnace center It turned out to be accompanied.
[0019]
Therefore, the present inventors do not require a special charging device in order to adjust the O / C in the blast furnace radial direction in the blast furnace charge to an appropriate distribution state in the control of the blast furnace cohesive zone. As a result of intensive research and investigations to be carried out using the above-mentioned charging equipment, in the bell-less blast furnace, the final coke charging in the furnace is appropriately determined in the blast furnace radial direction. It came to the conclusion that it was easy to solve the above problems by adjusting the position.
[0020]
In addition, various experiments were conducted to optimize the final coke charging position, and as a result of many trials and errors, the tilt angle of the turning chute was specified within a range of 20 to 35 °, and the center of the furnace was avoided. The final coke is charged at a position where the gas flow from the furnace to the furnace wall is not affected by the rising gas flow, and a dam-like coke deposit layer is once created, and the outside of the coke deposit layer (weir) By charging the iron ore between the furnace walls, the coke once deposited is used to flow the iron ore in the direction of the core, and the deposited coke is pushed into the center of the furnace. It was obtained that a chimney-like charge layer having good air permeability could be formed.
[0021]
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIGS. 1 and 2 schematically show the charge charged from the top of the blast furnace. In FIG. 1, the charge is stored in, for example, 1 hopper (1 dump) at the top of the coke layer previously charged. The final coke (C) is set to a specific angle within the range of 20 to 35 ° of the swivel chute, shifted from the center of the blast furnace by the swivel chute, and charged into a predetermined position in the blast furnace radial direction. (In this case, it is more effective to deposit the coke deposition layer thicker than the thickness of the layer normally charged).
Thereafter, charging is performed to the outside of the deposited portion where the final coke (C) in which the iron ore (O) has been previously charged is present. By performing such charging, the final coke (C) once deposited is pushed from the outside toward the furnace center by the flow of iron ore (O) toward the furnace center, and is shown in FIG. The distribution of the charge mainly composed of coke is obtained.
[0022]
That is, fluidized coke in the charged coke layer at the center of the furnace (as described above, the coke existing in the center of the furnace was soared by the gas flow that constantly rises in the center of the furnace, and it was fluidized because it repeatedly raised and lowered. The coke mixed with the deposited coke charged at the predetermined position is deposited, and the coke charged partially at the predetermined position remains on the outer periphery, and the iron ore is above it. Stones are stacked.
Since such a charge layer can be ensured, a chimney mainly composed of desired coke is formed in the center of the furnace, and the intended cohesive zone can be easily obtained.
[0023]
In the present invention, it is also possible to apply to the present invention the “charging method into the blast furnace” previously invented by the present inventors and already filed in Japanese Patent Application No. 9-341970. Of course, this is possible from the gist of the invention.
That is, the gist of the present invention is that “when charging the inside of the bell-less blast furnace into the blast furnace interior, after the coke is introduced into the lower part of the furnace top hopper just above the blast furnace, then the iron ore is introduced into the upper part thereof, After storing the coke and iron ore in layers, open the shut-off valve and charge the blast furnace with the charge through the swivel chute. As shown in FIG. 6, after the lower coke stored in the furnace hopper is charged and deposited at a predetermined position in the blast furnace radial direction, the tilt angle of the swivel chute is adjusted with the remaining iron ore as the main component. Since the coke deposited at the predetermined position by the iron ore can be pushed into the furnace center by moving outside the final charged coke layer deposited at the predetermined position and continuing the charging, The same purpose is achieved It is.
[0024]
For the charging of coke and iron ore in a normal blast furnace, the ratio of iron ore (O) and coke (C) in the total charging amount (O / C) is determined in advance according to the blast furnace operating situation, Coke and iron ore are sequentially charged so that coke and iron ore are alternately deposited in layers according to the ratio.
As the charging operation method of the above-mentioned charge for forming this deposited layer, various forms are adopted depending on characteristics on the charging equipment in the blast furnace, fluctuations in blast furnace operating conditions, and the like. In normal charging, charging of coke (C) and iron ore (O) is called one charge, but the charging order is, for example, (C ↓ O ↓), (C ↓ C ↓ O ↓) O ↓), (C ↓ C ↓ C ↓ O ↓ O ↓) and many other charging modes exist.
[0025]
In such a charging form, the final charging coke charged and deposited at a predetermined position in the radial direction of the blast furnace of the blast furnace referred to in the present invention is apparent from the object of the present invention as shown in FIG. It goes without saying that the coke (C) just before the iron ore (O) is charged is indicated.
Therefore, when coke is charged more than once within one charge, the coke that is charged last corresponds to this, but when the coke is charged only once, It is necessary to set in advance a charging pattern that can secure coke to be charged at a predetermined position in the blast furnace.
As described above, since the (O / C) ratio is determined from the charging amount in the entire blast furnace, the final coke amount should be determined in consideration of the (O / C) distribution.
[0026]
In the present invention, the tilt angle of the swivel chute for charging the final coke is regulated within the range of 20 to 35 ° (with respect to the furnace center axis (vertical line)). This value is the size of the blast furnace body. Depending on the charging line and the length of the swivel chute, the value has a width so that it can be selected according to the operating conditions of the blast furnace.
[0027]
If the angle of inclination of the swivel chute is less than 20 °, the charged final coke is too close to the furnace center, and it is entrained in the rising gas flow in the furnace center so that the coke is scattered and the effect of coke accumulation is obtained. If the inclination angle exceeds 35 °, the charged coke will be too close to the furnace wall side. This is because the pushing force is insufficient. The inclination angle is preferably 20 ° to 30 °.
[0028]
As described above, the tilt angle of the swivel chute is set to an optimal specific angle in response to the operating conditions of the blast furnace (may be a fixed fixed angle or an angle with some width). The final coke is charged and deposited at a predetermined position in the blast furnace radial direction of the blast furnace.
[0029]
Moreover, it is preferable that the final coke charged and deposited at a predetermined position in the blast furnace radial direction is charged uniformly over the entire blast furnace circumference. However, in charging with a turning chute, there is a case where the charging amount is biased depending on the variation in the particle size of the charged material and the fluctuation of the storage amount when flowing out from the hopper. When such a situation occurs, depending on the charging amount, when the length of the furnace circumference in which the coke is to be charged is long, the full length may not be satisfied in the furnace circumferential direction. Even if such a situation occurs, the final coke that has been charged and deposited exhibits its effect in the deposited portion, so that the purpose can be achieved although it is insufficient.
[0030]
Furthermore, when charging the iron ore after the final coke is charged to a predetermined position in the radial direction of the blast furnace throat, the charging is started from anywhere outside the final coke deposit (weir) and the blast furnace wall. Although it may be started, when considering the continuous movement of the swivel chute, it starts from the outside of the final coke deposit layer (weir), and the initial iron ore is used to push the deposited coke into the furnace center and sequentially toward the furnace wall. It is conceivable to adopt a charging form in which charging is continued.
Contrary to the above, the iron ore charging is started from the blast furnace wall side, and the charging is sequentially advanced toward the center of the furnace, and the charging is finished near the coke deposit layer. Also good.
[0031]
Furthermore, the final coke to be charged and deposited at a predetermined position in the radial direction of the blast furnace furnace is selected to have a particle size larger than that of ordinary coke in consideration of iron ore, maintaining the optimum particle size and maintaining the center of the furnace. Therefore, it is necessary to adjust so that a considerable amount of coke remains.
The coke does not require highly reactive coke in view of its reactivity, and low reactive coke is sufficient.
[0032]
In the present invention, the final coke that is charged and deposited at a predetermined position in the radial direction of the blast furnace hearth may be applied to all the charges every time the blast furnace is charged, but only at a rate of once per several charges. In many cases, it is preferable to adjust according to the blast furnace operation situation.
That is, since the operation status of the blast furnace varies depending on various factors, there may be a case where the gas flow in the center of the furnace becomes excessive in some cases. In such a case, this flow must be suppressed, and adjustment must be made so that an appropriate amount of gas flows also in locations other than the furnace center. Therefore, it is necessary to determine whether the gas flow in the furnace is appropriately performed and to determine the number of times.
[0033]
Here, there is a gas utilization rate as an index representing a gas flow situation in the furnace. This is usually ηCO and is represented by ηCO = (CO 2 / (CO + CO 2)). An example of the distribution state of ηCO in the radial direction of the blast furnace in a conventional bell-less blast furnace is shown in FIG. 7 (the blast furnace center is shown as 0 and the blast furnace wall is shown as 1). This figure shows the average value in a normal bell-less blast furnace. The distribution of ηCO is about 30% at the center of the furnace as shown by the dotted line, and the blast furnace radial direction is 0.5 to 0.7 (hereinafter, intermediate). And 50% for the blast furnace wall and about 45% for the blast furnace wall.
[0034]
Under such circumstances, the gas flow distribution in the furnace (ηCO) when the charging method of the charge into the blast furnace center according to the present invention is performed is about 5% at the furnace center as shown by the solid line, The value is about 52% in the middle part of the furnace and about 45% in the blast furnace wall, which improves the ηCO value in the center of the furnace, and can maintain a nearly ideal state of the distribution of gas flow in the furnace. it is obvious.
[0035]
However, this is the time when the above-mentioned blast furnace operating conditions did not change and the coke charging was ideally performed. In actual operation, as indicated by the solid line in FIG. However, it is not always possible to maintain a stable gas flow distribution, and an abnormal situation sometimes occurs in the gas flow distribution state. In such a case, according to the present invention, it is determined that an abnormality has occurred in the gas flow distribution on the basis of the distribution of ηCO in the furnace, and charged to a predetermined position in the blast furnace radial direction over the entire circumference of the furnace. The coke charging ratio (1 / n) of the final coke to be deposited is adjusted and controlled.
[0036]
That is, by increasing or decreasing the charging ratio (1 / n) of the charging coke of the final coke to be charged and accumulated as described above, the abnormality in the ηCO distribution is solved. Here, n represents the number of coke charging (number of charges).
Specifically, when the gas flow in the furnace center is excessive, n is increased, and conversely, when the gas flow in the furnace center is excessive, n is decreased. In addition to this, when an abnormality occurs in the ηCO distribution value at a location other than the furnace center portion, for example, when the gas flow distribution is such that ηCO increases to a value of 60% or more in the intermediate portion, the n number is set accordingly. By taking measures to increase, adjustment is performed so that the ηCO distribution value in the blast furnace radial direction can recover and maintain an appropriate value.
[0037]
In order to adjust this n number, there are cases where there is a specific variation in the ηCO distribution value depending on the blast furnace, and it is difficult to determine the ratio to one, and depending on the characteristics of the blast furnace, further, It is desirable to determine the appropriate value based on experience after many trials and errors in the blast furnace to be implemented in consideration of fluctuations.
[0038]
Generally, when the gas utilization rate (ηCO) exceeds 20% in the furnace center, the charging rate (1 / n) of coke charged to a predetermined position in the blast furnace radial direction is increased. Or when the gas utilization rate (ηCO) value satisfies 20% or less in the center of the furnace and the value of ηCO in the intermediate portion exceeds 60%. Therefore, it is necessary to reduce the charging ratio (1 / n) of the coke charged to a predetermined position in the radial direction of the blast furnace opening so as to be close to the ηCO distribution as shown by the solid line in FIG.
[0039]
In performing the above-described operation for changing the charging ratio (1 / n) of coke, the state in which the gas utilization rate (ηCO) deviates from the above value continues the same state even if at least 8 hours have elapsed. The ηCO value is out of the above range in consideration of sampling error, analysis error, etc. for measuring the gas utilization rate in the furnace, or temporary fluctuations in other factors. Even if it becomes, it is not preferable to take action immediately. On the contrary, not taking any action even after the lapse of the time leads to an adverse effect on blast furnace operation, which is also not preferable.
[0040]
【Example】
Hereinafter, examples in which the present invention is applied to an actual blast furnace will be described.
The blast furnace in which the operation was carried out is a blast furnace having an internal volume of 3280 m ³ during pulverized coal injection. Table 1 shows the charging pattern of the charge according to the present invention and the O / C for all charges in the blast furnace.
In addition, the results of the present invention showed the effect on the basis of the gas utilization rate in the central part of the shaft upper sonde. All of these were the same charging method continued for 7 days, and the numerical values in Table 1 represent the average values during that period.
[0041]
[Table 1]

[0042]
Run numbers 1 to 7 were carried out with respect to charging patterns {circle around (1)} and {circle around (2)}, and run numbers 8 to 11 were carried out with respect to the particle size of coke and the use of low-reactivity coke. In addition, about the implementation number 12, the prior art example was given for the comparison.
As is apparent from Table 1, according to the present invention, a good cohesive zone was stably obtained as compared with the conventional example. As a result, the operation of the blast furnace was stabilized and a high output ratio could be secured. It was.
[0043]
【The invention's effect】
As described above, by carrying out the charging method of the present invention, coke can be distributed properly and reliably in the radial direction of the furnace, and an appropriate blast furnace cohesive zone shape can be stably obtained. This makes it possible to secure an appropriate blast furnace center gas flow and to form a stable peripheral gas flow in the circumferential direction of the furnace.
[Brief description of the drawings]
FIG. 1 is a diagram showing an initial state of charging a charge into a blast furnace according to the present invention.
FIG. 2 is a view showing a state of a charge layer of a charge obtained by the charging method of the present invention.
FIG. 3 is a diagram showing an example of an inverted V-type cohesive zone in a blast furnace.
FIG. 4 is a diagram showing shapes of an iron ore layer and a coke layer in normal blast furnace charging.
FIG. 5 is a diagram schematically showing a state of charged coke in the furnace center when the rising gas flow in the furnace center is large.
FIG. 6 is a diagram showing a storage state of charges in a furnace hopper.
FIG. 7 is a diagram showing a distribution state of gas utilization rate (ηCO) in a blast furnace radial direction in a bell-less blast furnace.

Claims (9)

In order to deposit coke and iron ore alternately in layers in the bell-less blast furnace, the final charge that is charged immediately before the iron ore via a swivel chute when the charge that sequentially charges coke and iron ore is loaded into the blast furnace When charging the coke, the tilt angle of the turning chute is set to a specific angle within a range of 20 to 35 °, and then the final coke is charged to a predetermined position in the blast furnace radial direction to form a weir. A method for charging a furnace core in a blast furnace, wherein the iron ore is charged between the outer side of the final coke deposit and the blast furnace wall using the swirl chute. In order to deposit coke and iron ore alternately in layers in the bell-less blast furnace, the final charge that is charged immediately before the iron ore via a swivel chute when the charge that sequentially charges coke and iron ore is loaded into the blast furnace In charging the coke, after the coke is introduced into the lower part of the furnace hopper directly above the blast furnace, iron ore is then introduced into the upper part thereof, and the coke and iron ore are stored in layers in the furnace hopper. The tilt angle of the swivel chute is set to a specific angle within a range of 20 to 35 °, and then the shut-off valve is opened, and most of the lower storage coke is used as the final coke charged immediately before the iron ore. was charged to a predetermined position in the direction allowed deposited dam-shaped, then wherein the swivel chute to move to the outside of the deposition portion of the final coke starts charging the upper reservoir iron ore blast furnace Charge charging method to the definitive furnace center.   3. The blast furnace center according to claim 1, wherein the iron ore after the final coke is charged is sequentially charged from the outer side of the coke deposit part toward the blast furnace wall side. 4. The charging method to the club.   The final coke charged and deposited at a predetermined position in the blast furnace radial direction of the blast furnace is charged into the blast furnace with a larger particle size. The charging method to the furnace center in a blast furnace.   5. The final coke charged and deposited at a predetermined position in the blast furnace radial direction of the blast furnace is charged into the blast furnace by changing its reactivity to low reactivity. The charging method to the furnace center part in the blast furnace of the crab. The final coke to be charged and deposited at a predetermined position in the blast furnace radial direction of the blast furnace is to adjust and control the coke charging ratio (1 / n) according to the gas utilization rate value in the furnace radial direction at the top of the blast furnace furnace. 6. A method for charging a charge into a furnace center in a blast furnace according to any one of claims 1 to 5.
The coke charging ratio (1 / n) is, for example, (C ↓ O ↓), (C ↓ C ↓ O ↓ O ↓), (C ↓ C ↓ C ↓ O ↓ O ↓), etc. When the charge of coke (C) and iron ore (O) in which the form exists is one charge, it means the number of coke charges with respect to the number of charge charges (n).   In claim 6, when the value of the gas utilization rate (ηCO) exceeds 20% at the furnace center, the coke charging ratio (1 / n) of the final coke charged to a predetermined position at the blast furnace radius. ) In the blast furnace, characterized by increasing the charge to the furnace center.   In claim 6, when the value of the gas utilization rate (ηCO) satisfies 20% or less in the furnace central portion and the value of ηCO in the middle portion of the furnace becomes 60% or more, A charge charging method for a furnace center in a blast furnace, characterized in that the coke charging ratio (1 / n) of the final coke charged to a predetermined position with a radius is reduced.   If at least 8 hours have passed after the gas utilization rate (ηCO) has deviated from the value defined in claim 7 or claim 8, the final coke charged to a predetermined position at the blast furnace radius A method for charging a charge into a furnace center in a blast furnace, wherein the coke charging ratio (1 / n) is increased or decreased.

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