JP2001140008A - Operating method of blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably operate by simply and highly accurately grasping the condition in a blast furnace at the lower part of the furnace. SOLUTION: The liquid permeability and the temperature in the furnace in the radial direction at a tuyere part in the blast furnace, are measured to obtain the liquid permeability distribution and the temperature distribution in the furnace in the radial direction. The activity in the lower part of the blast furnace, is grasped with these liquid permeability distribution and the temperature distribution in the furnace to control the operating condition in the blast furnace. In this way, since the aggravation of the liquid permeability near a raceway for fear of the operation in the case of blowing pulverized fine coal, etc., can simply be grasped in high accuracy whether the blasting is stopped or not, the stable operation can be executed by controlling the operational condition according to the grasped state in the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a blast furnace, and more particularly, to the activity in the lower part of the furnace (the degree of good gas permeability and liquid permeability in the furnace. Is good, and if the gas permeability and liquid permeability are poor, the activity is poor.)

[0002]

2. Description of the Related Art In a blast furnace operation for producing pig iron, an iron source material and coke are charged in layers from the furnace top, but located below a cohesive zone where the iron source material softens and fuses at the lower part of the furnace. In the coke packed bed, the gas blown from the tuyere rises from the lower part, and the molten iron slag generated by the reduction and melting of the iron source material drops from the upper part.

[0003] Most of the coke in the lower part of the furnace moves toward the combustion zone (raceway) in front of the tuyere and burns and disappears. Form coke.

On the other hand, the iron source material and coke charged from the upper part of the furnace reach the lower part of the furnace in about several hours, but it is considered that the replacement of the core coke takes several days to several weeks. It is important to grasp the condition in blast furnace operation.

[0005] Since the core coke stays in the center of the furnace, it is a factor affecting gas and liquid aeration and liquid flow. It is obtained by inserting, coke particle size,
For example, a powder ratio (for example, what percentage is 3 mm or less), an estimated history temperature based on the degree of graphitization, and the like are used.

Recently, Japanese Patent Application Laid-Open No. 10-18321
No. 1 proposes a blast furnace operation method that measures the height of the raceway by measuring the thrust at the time of insertion of the sonde to grasp the filling condition of the furnace interior, and controls the blower specifications based on this grasp. Have been.

[0007]

However, the method of grasping the condition inside the furnace at the lower part of the furnace by inserting a sampler from the tuyere during the cold season is high in accuracy, but the situation inside the furnace is grasped only during the cold season. In addition to this, there is a time constraint that the process cannot be performed, and there is a disadvantage that the cost required for grasping the condition inside the furnace is high. Further, in order to grasp the condition inside the furnace, it is necessary to perform each test on the collected sample, and the result cannot be obtained on-time.

[0008] Further, in the grasp of the inside of the furnace based on the thrust proposed in Japanese Patent Application Laid-Open No. H10-183211, the thrust to be measured is determined by the relative position of the sonde and coke at the time of measurement even in the same inside of the furnace. Since it changes greatly, there is a problem in accuracy.

The present invention has been made in view of the above-mentioned problems of the conventional method, and enables stable operation by easily and accurately grasping the inside of the furnace at the lower part of the furnace. It aims to provide a blast furnace operating method.

[0010]

In order to achieve the above-mentioned object, a method for operating a blast furnace according to the present invention is characterized in that the distribution of liquid permeability in the radial direction of the tuyere portion of the blast furnace and the distribution of the temperature in the furnace make it possible to activate the blast furnace at the lower part of the blast furnace. The operating conditions of the blast furnace will be controlled based on the degree of operation. By doing so, the condition inside the furnace at the lower part of the furnace can be grasped simply and with high accuracy, and stable operation becomes possible.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors inserted a furnace core sonde equipped with an optical fiber and a two-color thermometer from a tuyere of a blast furnace, and analyzed the image of the obtained molten iron slag. It was found that there was a distribution in the amount, which reflects the state of gas permeability and liquid permeability in the furnace.

That is, the fact that the furnace temperature is high means that
This means that the inside of the furnace is activated, which does not deny that the gas is flowing well in the furnace. On the other hand, as for the liquid permeability in the furnace, a predetermined amount is dripped per day regardless of good or bad. Therefore, by measuring the furnace temperature and the distribution of the flow rate in the above-mentioned radial direction in the furnace, it is possible to accurately grasp the furnace state in the lower part of the blast furnace.

The method for operating a blast furnace according to the present invention is based on the above-mentioned knowledge, and measures the liquid permeability in the radial direction at the tuyere portion of the blast furnace and the temperature in the furnace to obtain the liquid permeability in the radial direction. The distribution and the temperature distribution in the furnace are obtained, the activity in the lower part of the blast furnace is grasped from the liquid permeability distribution and the temperature distribution in the furnace, and the operating conditions of the blast furnace are controlled.

In the method for operating a blast furnace according to the present invention, a method for measuring the liquid permeability in the radial direction at the tuyere portion of the blast furnace and the temperature in the furnace may be, for example, a method using a blast furnace blade equipped with an optical fiber and a two-color thermometer. Although it is conceivable to insert from the mouth, any method may be adopted as long as the liquid permeability in the radial direction and the furnace temperature can be measured.

Further, in the blast furnace operating method according to the present invention, the control of the blast furnace operating conditions based on the grasped activity includes, for example, changing the pulverized coal injection conditions, changing the oxygen enrichment rate, and controlling the blast furnace. This is performed by changing the particle size of the coke to be charged. An example is shown below.

In the case where the core temperature is leveling or rising, and when the flow rate in the furnace core and the flow rate in the furnace wall are flat, it is determined that there is no abnormality in both the furnace core and the furnace wall. , Continue operation.

[0017] When the core temperature is leveling or rising, the flow rate in the furnace core decreases, and when the flow rate in the furnace wall increases, there is no abnormality in both the furnace core and the furnace wall. And continue the operation as it is.

When the core temperature is flat and the flow rate in the furnace core increases and the flow rate in the furnace wall decreases, it is determined that there is a problem on the furnace wall side. Control such as raising the temperature in front of the tuyere by raising the conversion rate is performed.

In the case where the core temperature is lowered and the flow rate in the furnace core is equal to the flow rate in the furnace wall, it is determined that both the furnace core and the furnace wall have a problem, For the furnace core, for example, the center gas flow is strengthened by increasing the particle size of the coke to be charged, and for the furnace wall, the tuyere is increased, for example, by increasing the oxygen enrichment rate. Control such as raising the previous temperature is performed.

When the core temperature decreases and the amount of liquid flowing through the furnace core decreases, and when the amount of liquid flowing through the furnace wall increases, it is determined that there is a problem with the core. Control such as strengthening the center gas flow by increasing the particle size of the coke to be charged is performed.

When the temperature of the core decreases, the amount of liquid flowing through the furnace core increases, and when the amount of liquid flowing through the furnace wall decreases, it is considered that both the core and the furnace wall have a problem. Judge and perform the same control as

According to the method for operating a blast furnace according to the present invention, the condition inside the furnace at the lower part of the furnace can be grasped simply and with high accuracy without being limited to when the wind is shut off, so that the operating conditions can be controlled according to the grasped condition inside the furnace. By doing so, stable operation becomes possible.

[0023]

EXAMPLES In order to confirm the effects of the blast furnace operating method according to the present invention, results of applying the method of the present invention to a blast furnace having an inner volume of 2700 m ³ will be described below. FIG. 1 is a schematic view of a blast furnace to which the blast furnace operating method according to the present invention is applied. In FIG. 1, 1 indicates a blast furnace, 2 indicates a tuyere, and 3 indicates a raceway.

In the present embodiment, a furnace core sonde 4 equipped with an optical fiber and a two-color thermometer is inserted into the furnace from the tuyere 2, and the furnace temperature in the radial direction at the lower part of the furnace is measured by the two-color thermometer. The image obtained by using an optical fiber for the liquid passing state was subjected to image analysis.

(Embodiment 1) FIG. 2 shows a reference operation (solid line) and a certain period (dashed line) when pulverized coal is injected.
Distribution of molten iron slag in the radial direction at
Shows the furnace temperature change in the same case.

As shown in FIG. 2, during the standard operation (solid line), the flow rate in the radial direction in the furnace is about 1: 3 from the furnace core to the middle part and the ratio to the furnace wall is about 1: 3. However, it can be seen that, during a certain period, the flow rate from the furnace core portion to the intermediate portion is about 3/2 to 2 times that of the reference operation (broken line). On the other hand, as shown in FIG. 3, it can be seen that the furnace temperature hardly changed between the reference operation and a certain period (corresponding to the above).

From the above, this is because, in a certain period,
It is considered that the flow of liquid from the center of the furnace to the middle of the furnace increased as a result of the deterioration of the liquid permeability at the back of the raceway due to the injection of pulverized coal. If such a situation continues, the tuyere is broken and the furnace condition becomes unstable, so in order to improve the liquid permeability near the raceway, raise the coke ratio and increase the tuyere As a result of taking action to raise the temperature, the furnace condition was able to stably change.

Example 2 In another period (broken line), the distribution of molten iron slag in the radial direction is as shown in FIG. 4, and the change in furnace temperature is as shown in FIG. Was done.

In this case, the temperature at the center of the furnace has decreased, and the flow rate has increased from the furnace core to the middle as compared with the reference time (solid line). Because of the decrease, it was determined that both the furnace core and the furnace wall had a problem (corresponding to the above).

Therefore, for the furnace core, the central gas flow is strengthened by increasing the particle size of the coke charged, and for the furnace wall, the oxygen enrichment rate is increased. By controlling the temperature in front of the tuyere, the furnace condition could be changed stably.

[0031]

As described above, according to the blast furnace operating method of the present invention, the deterioration of the liquid permeability near the raceway, which is a concern at the time of pulverized coal injection operation or the like, is not limited to when the wind is shut off. Since it can be grasped easily and with high accuracy,
By controlling the operating conditions according to the in-furnace situation,
Stable operation becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic view of a blast furnace to which a blast furnace operating method according to the present invention is applied.

FIG. 2 is a diagram illustrating a drop distribution of molten iron slag in a radial direction during a reference operation (solid line) and a certain period (dashed line) in Example 1.

FIG. 3 is a diagram showing a furnace temperature change in the same case as in FIG. 2;

FIG. 4 is a diagram illustrating a dripping distribution of molten iron slag in a radial direction during a reference operation (solid line) and another period (broken line) in Example 2.

FIG. 5 is a diagram showing a furnace temperature change in the same case as in FIG. 4;

[Description of Signs] 1 Blast Furnace 2 Tuyere 3 Raceway 4 Furnace Sonde

Claims (1)

[Claims] 1. A liquid permeability and a furnace temperature in a radial direction at a tuyere portion of a blast furnace are measured to obtain a liquid permeability distribution and a furnace temperature distribution in the radial direction, and the liquid permeability distribution and the furnace temperature distribution are obtained. A method for operating a blast furnace, characterized in that the degree of activity in the lower part of the blast furnace is grasped by means of the method and the operating conditions of the blast furnace are controlled.