JPH09241711A - Method for estimating crumbling quantity of coke and preventing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the crumbling of coke as little as possible and to execute a stable blast furnace operation at high grade by surely estimating the crumbling quantity piled in the furnace with iron raw material charge and executing the adjustment of an armor plate, pellet ratio and stock line based on this estimation. SOLUTION: The surface conditions in the furnace diameter direction of the charged material piled in the furnace at just before and just after charging the iron raw material into the furnace are measured. The layer thickness distribution of the iron raw material in the furnace diameter direction is obtd. from these both measured values and also, a layer thickness reference value at the time of assuming that the charged iron raw material is uniformly charged in the furnace diameter direction, is estimated. The difference is obtd. by deducting the estimated layer thickness reference value from the measured layer thickness distribution, and each area at each part having negative error is obtd. and these area is integrated in the circular direction of the blast furnace to estimate the crumbling of the coke. Further, based on this estimated quantity, one or more items among the armor plate, pellet ratio and stock line are adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of estimating the amount of collapse of coke deposited in a furnace by charging an iron material into a furnace of a blast furnace, and a method of preventing the collapse. It is about.

[0002]

2. Description of the Related Art A blast furnace is a countercurrent reaction facility between a charge charged from the top of the furnace and a high-temperature reducing gas rising from the lower part of the furnace. In order to maintain the operation of the blast furnace in a stable state, It is important to appropriately maintain the gas-solid reaction in the furnace, and it is necessary to appropriately control the solid flow, gas flow, heat transfer phenomenon, reduction reaction, and other phenomena in the furnace. For that purpose, it is important to accurately control the distribution of the charge in the furnace. For this reason, for example, in Japanese Patent Publication No. 61-24445, the surface shape of the charge at the top of the blast furnace is measured, and this measurement is performed. The distribution of the falling velocity in the radial direction of the furnace is determined by a statistical method using the shape, the layer thickness distribution ratio is grasped based on this falling velocity, and it is fed back to the distribution control of the charging, and the distribution of the charging in the blast furnace It is proposed to properly adjust the temperature and maintain stable reactor conditions.

[0003]

However, when the layer thickness distribution of the charge is determined from the surface shape of the charge and the descending velocity distribution in the furnace radial direction, it has already been charged and deposited at the time of charging the iron raw material. It is not considered that the physical collision with the lower layer changes the layer thickness distribution of the lower layer and changes the layer thickness distribution of the charge. In the method proposed in Japanese Patent Publication No. 61-24445, in the case where the amount of coke collapse greatly changes due to a change in charging conditions such as a change in particle size of the charged material, a high-ranking furnace is used in charging material distribution control by feedback. It is difficult to stabilize the situation.

According to the present invention, when the iron raw material is charged into the furnace, the collapse amount of the coke deposited immediately before the iron raw material and accumulated in the furnace is accurately estimated, and the armor plate, An object of the present invention is to adjust the pellet ratio and one or more stock lines to reduce the coke collapse as much as possible and perform stable blast furnace operation at a high level.

[0005]

Means for Solving the Problems The present invention has been made to solve the above problems, and means 1 thereof is for charging a charge such as coke and iron raw material into a blast furnace. After charging the coke into the blast furnace, immediately before and after charging the iron raw material, the surface shape in the furnace radial direction of the charge deposited in the furnace was measured. Along with obtaining the layer thickness distribution in the radial direction, the layer thickness reference value when the charged iron raw material is assumed to be uniformly charged in the furnace radial direction is estimated, and the estimated layer thickness reference is obtained from the measured layer thickness distribution. This is a method in which coke collapse is estimated by subtracting the values to obtain the difference, obtaining the area of the portion where the error becomes negative, and integrating the area in the circumferential direction of the blast furnace.

Further, means 2 is a coke collapse ratio obtained by dividing the amount of coke collapse estimated in means 1 by a coke base, and an armor plate provided at the top of the blast furnace according to the coke collapse ratio, the iron raw material. It is a method of preventing coke collapse by adjusting the pellet ratio and one or more of the stock lines.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In order to continue the stable operation of a blast furnace, it is necessary to create a stable cohesive zone and to maintain an appropriate gas flow in the massive zone. The ore / coke (hereinafter simply referred to as O / C) distribution in the furnace radial direction has a large influence on these, and an inverted V-shaped cohesive zone formed when the O / C distribution is uniform in the furnace radial direction. However, it is said to be most preferable for stable operation of the blast furnace because it also improves the gas reduction efficiency.

However, when the O / C distribution in the furnace radial direction is maximized in the middle part,
A W-shaped cohesive zone is formed. When this cohesive zone forms a W shape, the bottom end of the cohesive zone moves to the core side, so that the space between the core and the bottom end of the cohesive zone becomes narrow, and the gas generated in the raceway The gas reduction efficiency also deteriorates due to poor ventilation and unstable gas flow.

Further, the coke supplied to the raceway is composed of coke in the peripheral portion and coke passing between the core and the cohesive zone. When this supply is stopped, a cavity is formed in the lower part of the cohesive zone, and Suspending on the shelf directly above the mouth, slippage occurs,
Unloading becomes irregular, which adversely affects blast furnace operation.
If the O / C distribution is maximized in the central portion, a low head cohesive zone is formed. In this case,
The gas flow is directed toward the periphery, and the temperature in the peripheral portion of the furnace rises, which gives a load to the furnace body.

Further, since the root of the cohesive zone is enlarged due to the temperature rise, ventilation in this part is obstructed and the gas flow becomes unstable, so that hanging on the top of the cohesive zone root easily occurs. It adversely affects blast furnace operation. When the O / C distribution is maximized in the peripheral portion, the above-mentioned inverted V-shaped cohesive zone shape in which the head is high and the position of the root is low. In this case,
Since the heat level around the furnace is reduced, the reduction at the periphery of the cohesive zone becomes difficult, and the mine is dropped, and the heat at the bottom of the furnace falls and the bottom of the furnace becomes inactive, which adversely affects the operation of the blast furnace.

Therefore, in order to stabilize the operation of the blast furnace, it is desirable to form a uniform O / C distribution in the furnace radial direction and to form an inverted V-shape as the shape of the cohesive zone. When the coke base is reduced, the layer thickness of the coke becomes thinner and the coke is destroyed by the ore.
The degree of non-uniform distribution becomes remarkable, and the problems described above occur.

Therefore, in the present invention, the layer thickness distribution in the furnace radial direction when the iron raw material is charged after charging the iron raw material and the layer thickness distribution in the furnace radial direction when the iron raw material is charged after the coke charging are set. It was found that there was a difference, and as a result of examining this difference, it was found that it was due to the collapse of the coke charged immediately before the iron raw material was charged. Therefore, assuming the layer thickness distribution of the iron raw material when the coke collapse does not occur when the iron raw material is charged after the coke charging, the layer thickness of the measured value when the iron raw material is charged after the coke charging is assumed. The amount of coke collapse was estimated from the difference in distribution.

Specifically, the amount was estimated by the following method.
That is, the surface shape in the furnace radial direction of the charge deposited in the furnace was measured with a profile meter immediately before and immediately after the charging of the iron raw material after the charging of the coke. The layer thickness reference value SK is estimated when the layer thickness distribution in the radial direction is obtained and the charged iron raw material is assumed to be uniformly loaded in the furnace radial direction, and the estimated layer thickness is calculated from the measured layer thickness distribution. The thickness reference value SK is subtracted to obtain the difference, and the area S of the portion where the difference becomes negative is obtained (see FIG. 1).

The area S is integrated in the radial direction of the furnace and the product of the coke specific gravity is estimated as the coke collapse amount. The charging distribution of the blast furnace charge H is adjusted according to the estimated amount, and the collapse amount is adjusted. By maintaining a stable low value, the O / C distribution in the furnace radial direction can be made more accurate, and the coke collapse in the peripheral area of the furnace reduces the coke layer thickness, resulting in excessive ore. It is possible to avoid the accumulation and increase of O / C in this portion, and it is possible to adjust the gas flow in the furnace and the shape of the cohesive zone to a good state.

The amount of coke collapse is adjusted by adjusting one or more of the armor plate MA, the pellet ratio, and the stock line STL.
By adjusting the armor plate MA, by changing the armor notch when charging the coke, the charging direction when the coke is charged into the furnace can be adjusted, and the charging distribution of the coke can be made flat. The iron raw material charged next is gently charged into the furnace, and as a result, coke collapse can be reduced.

Regarding the pellet ratio, by increasing the pellet ratio in the iron raw material charged immediately before the charging of the coke, the repose angle of the iron raw material stone in the layer immediately before the coke charging becomes smaller, so that the distribution of the iron raw material is in the furnace. Because it approaches a flat in the radial direction,
The coke charged therein tends to be deposited flatly, and coke collapse can be reduced as in the above. Further, by adjusting the stock line STL, it is possible to adjust the inflow rate and the angle when the coke and the iron raw material are charged into the furnace to change the flow-in condition so that the charge can be flatly distributed. Similarly, the breakage of coke can be reduced.

[0017]

EXAMPLE An example of the present invention will be described below with reference to FIG. 2 and Table 1. The blast furnace used in the present invention has an internal volume of 5245 m ³ , a nominal tapping capacity of 12000 t / day, and a charging mode of charging is 1C, 2C, 1O, 2O, (C: coke, O: ore,
Batch Nos. 1 and 2 are batch Nos. ) [1C: 12 to 16t, 2C:
12-18t, 10: 65-67t, 2O: 65-67
t], the air flow rate: 8,000 to 8,200 Nm ³ / mi
n, blast pressure: 4.2 to 4.4 kg / cm ² , oxygen enrichment: 8,000 to 12,000 Nm ³ / h Bell type blast furnace.

The charge dumped from the large bell as shown in FIG. 2 is kicked by the armor plate MA. The charge distribution shape of the charge is measured before and after the dump by the profile meter PF to obtain the layer thickness distribution in the furnace radial direction.

[0019]

[Table 1]

In the inventive example 1 in Table 1, the position of the armor plate MA was adjusted from the operating state of the comparative example 1 at the time of charging the second batch of the coke 2C (moved to the furnace wall side by 20 mm:
6 notches → 4 notches)
It was possible to suppress the amount of coke collapse when the ore 1O was charged in the batch (2.79t → 0.92t) (FIG. 3 → FIG. 4). For this reason, it is possible to prevent excess coke from flowing into the center of the furnace and to prevent excess ore from depositing near the furnace wall.
The gas flow was optimized and ventilation was improved, the gas reduction efficiency was improved, the heat load was suppressed, and the unloading fluctuation index was decreased, resulting in a stable furnace condition.

In the invention example 2, the stock line position is adjusted from 1.0 m to 0.9 m from the operating condition of the comparative example 2 so that the amount of coke collapse at the time of charging 1 O can be suppressed ( (Fig. 5 → Fig. 6), the furnace conditions could be improved in the same manner as above. Inventive Example 3 has 10% from the operating state of Comparative Example 3.
By changing the ratio of the pellets of 20 and 2O from 50:50 to 30:70, it is possible to suppress the amount of coke collapse by forming a base that makes the charging distribution state of coke flat (Fig. 7). → (Fig. 8), it was possible to improve the furnace conditions in the same manner as above.

Example 4 of the present invention is different from the operating state of Comparative Example 4 in that the position of the armor plate MA is adjusted (moving to the furnace wall side by 20 mm: 6 notches → 4 notches) at the time of charging the 2C, so that the stock line By adjusting the position from 1.0 m to 0.9 m, the ratio of the pellets of 10 and 20 was 50:50.
By changing the ratio from 50 to 30:70, the amount of coke collapse could be suppressed (Fig. 9 to Fig. 10), and the furnace conditions could be improved in the same manner as above.

As is apparent from Table 1, the present invention has improved gas flow, gas reduction, ventilation, heat load, unloading variation index, etc. as compared with the comparative example, and the furnace condition is stabilized, and at the same time, the fuel ratio is reduced. It is clear.

[0024]

INDUSTRIAL APPLICABILITY The present invention makes it possible to maintain a stable blast furnace operation at a low fuel ratio and a high level by properly estimating the coke collapse amount, suppressing the coke collapse amount, and maintaining it. The effect in this field is great.

[Brief description of drawings]

FIG. 1 is a relative layer thickness distribution diagram relatively illustrating the relationship between the difference in layer thickness distribution before and after charging 1O and the layer thickness SK when 10 is uniformly charged in the furnace.

FIG. 2 is a side sectional view showing a charging device and a detection end in a side sectional view of a blast furnace.

FIG. 3 is a 10O relative layer thickness distribution chart in Comparative Example 1.

FIG. 4 is a 10O relative layer thickness distribution chart in the case of Invention Example 1.

FIG. 5 is a 10O relative layer thickness distribution chart in Comparative Example 2

FIG. 6 is a 10O relative layer thickness distribution chart in Inventive Example 2;

FIG. 7 is a 10O relative layer thickness distribution chart in Comparative Example 3.

FIG. 8 is a 10O relative layer thickness distribution chart in the case of Invention Example 3.

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[Procedure amendment]

[Submission date] July 9, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a relative layer thickness distribution diagram relatively illustrating the relationship between the difference in layer thickness distribution before and after charging 1O and the layer thickness SK when 10 is uniformly charged in the furnace.

FIG. 2 is a side sectional view showing a charging device and a detection end in a side sectional view of a blast furnace.

FIG. 3 is a 10O relative layer thickness distribution chart in Comparative Example 1.

FIG. 4 is a 10O relative layer thickness distribution chart in the case of Invention Example 1.

FIG. 5 is a 10O relative layer thickness distribution chart in Comparative Example 2

FIG. 6 is a 10O relative layer thickness distribution chart in Inventive Example 2;

FIG. 7 is a 10O relative layer thickness distribution chart in Comparative Example 3.

FIG. 8 is a 10O relative layer thickness distribution chart in the case of Invention Example 3.

FIG. 9 is a 10O relative layer thickness distribution chart in Comparative Example 4.

FIG. 10 is a 10O relative layer thickness distribution chart in the case of Invention Example 4.

Claims (2)

[Claims] 1. When charging an iron raw material such as sinter or pellets and coke into a blast furnace, immediately after charging the iron raw material after charging the coke into the blast furnace. And immediately after that, the surface shape in the furnace radial direction of the charged material deposited in the furnace was measured, and the layer thickness distribution in the furnace radial direction of the charged material was obtained from both measured values, and the charged iron The layer thickness reference value when assuming that the raw materials are uniformly charged in the furnace radial direction is estimated, and the difference is obtained by subtracting the estimated layer thickness reference value from the measured layer thickness distribution, and the difference is negative. A method for estimating a coke collapse amount, which comprises: calculating an area of a broken portion and integrating the area in a circumferential direction of a blast furnace to estimate a coke collapse amount. 2. The estimated coke collapse amount according to claim 1,
Divide by the coke base is the coke collapse rate,
A coke collapse prevention method comprising adjusting one or more of an armor plate provided at the top of a blast furnace, a pellet ratio in the iron raw material, and a stock line according to the coke collapse ratio.