JP3004804B2 - Blast furnace core activity detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quickly detecting a deadman inactivation of a blast furnace which reduces the productivity of a blast furnace.

[0002]

2. Description of the Related Art In the lower center of a blast furnace, there is an area where solids move extremely slowly. This region is called a furnace core, in which hot metal or molten slag drops from the upper portion, and gas generated in the tuyere rises from the lower portion. If the ventilation and liquid permeability in the furnace core is hindered and inactivated, the productivity of the blast furnace decreases. Factors that inactivate the furnace core include adhesion of fine powder.

[0003] In particular, in the recent blast furnace operation method in which the amount of pulverized coal fed from tuyeres is increased, pulverized coal that cannot be completely burned in the tuyeres is trapped in the furnace core to deactivate the furnace core. Easy to do. When the core is deactivated, the productivity of the blast furnace is greatly reduced. Therefore, it is necessary to detect the activity of the mandrel and adjust the operating conditions of the blast furnace according to the state of the mandrel.

[0004] Various proposals have conventionally been made for detecting the activity of the furnace core. For example, Japanese Patent Application Laid-Open No. 2-775
In Japanese Patent Publication No. 05, slag in a mandrel is analyzed, and the activity of the mandrel is determined from the slag composition. JP-A-3-1
In JP 83707, the core coke depth from the tuyere tip to the core coke surface layer is measured with a sonde, and the activity of the core is determined based on the core coke temperature estimated from the core coke depth. . In Japanese Patent Application Laid-Open No. Hei 3-215610, the active state of the furnace core is maintained by detecting the insertion resistance value of a sonde inserted into the furnace core and operating the probe so that the insertion resistance value is equal to or less than a predetermined value. . In Japanese Patent Application Laid-Open No. 3-243708, the physical characteristics of the furnace core are estimated from the attenuation rate and propagation speed of the shock wave propagating in the furnace core.

[0005]

In the method disclosed in Japanese Patent Application Laid-Open No. 2-77505, in which the activity of the furnace core is determined from the slag composition, it takes a long time to analyze the slag composition. For this reason, there is a possibility that an action for changing the operating condition according to the activity of the furnace core may be delayed. In addition, particularly when the furnace core is in an inactive state, the composition of slag in the furnace core varies greatly.
For this reason, an estimation error occurs in the activity of the mandrel obtained from the slag composition, and there are cases where operating conditions corresponding to the actual mandrel conditions cannot be taken.

On the other hand, JP-A-3-183707, JP-A-3-215610, and JP-A-3-243708
In the method disclosed in Japanese Patent Application Laid-Open Publication No. H08-157, the reliability of the correlation between the state of activation of the furnace core and each measured value is insufficient. for that reason,
Even if the operating conditions are adjusted based on the measured values, the core may not be maintained or restored in the active state. For this reason, in the actual blast furnace operation, at present, the ventilation of the furnace core is eliminated by the fluctuation of the blowing pressure, and the air permeability and liquid permeability of the furnace core are controlled.

[0007] The present invention has been devised to solve such a problem, and deactivates the core by determining the activity based on the pressure difference between the core and the tuyere tip. Is to be easily and instantaneously detected.

[0008]

In order to achieve the object, a method for detecting a core activity of a furnace according to the present invention comprises: placing a sonde having a plurality of pressure measuring ports in a longitudinal direction in a furnace from a blast furnace tuyere in a radial direction. The pressure difference between the core and the tuyere tip is detected, and the activity of the core is detected based on the pressure difference.

[0009]

[Operation] The present inventors have conducted various investigations and studies regarding the direct measurement of the state of inactivation of the furnace core. Initially, an attempt was made to determine the core activity using only the pressure fluctuation inside the core. However, when the furnace core is deactivated, the pressure loss in the entire blast furnace increases and the blast pressure increases, so that the gas flow in the upper part of the furnace and the gas flow due to the core deactivation are distinguished. It was difficult to do.

The present inventors have further studied and found that the pressure difference between the core and the tuyere tip has a close correlation with the inactivation of the core. That is, when the furnace core becomes inactive, the flow of gas into the furnace core is hindered, and the pressure difference between the tuyere tip and the furnace core increases.

The pressure difference between the tuyere tip and the furnace core can be measured easily and quickly by inserting a sonde provided with a plurality of pressure measuring ports from the blast furnace tuyere in the radial direction. When the pressure difference measured by the sonde is used, the inactivation of the core can be detected easily and accurately, and the deterioration of the furnace condition caused by the inactivation of the core can be predicted in a short time. Become.

It is desirable to set the timing of the measurement when the pressure loss in the furnace increases. Under the condition of the furnace where the pressure loss in the furnace is increased, the pressure measuring sonde is inserted into the furnace from the tuyere of the blast furnace in the radial direction. When the pressure difference between the core and the tuyere tip at that time exceeds a certain set value, it is determined that the core is inactivated. Then, actions such as reducing the amount of pulverized coal injected and increasing the amount of oxygen during blowing are performed so as to restore the activity of the furnace core. If the pressure difference between the core and the tuyere tip is smaller than the set value even if the pressure loss in the furnace increases, it is determined that the gas flow in the upper part of the furnace has deteriorated, and the charge distribution is changed. Recover the furnace condition by increasing the strength.

[0013]

【Example】

Example 1: As shown in FIG. 1, when the pressure loss in the furnace increased, a sonde was inserted into the blast furnace and the pressure difference was measured. At this time, as shown in FIG. 2, a blast furnace having a distance L of 5.8 m from the furnace center C to the outer surface of the side wall brick 1 was used. Then, insert the sonde 3 from the tuyere 2, the position P ₁ and the furnace center C in the furnace core from the furnace center C at a distance of 0.5m
The position P ₂ of the tuyere in the distance of 3.7m with a pressure measuring point.

When the furnace condition was good, the pressure difference between the pressure measurement points P ₁ and P ₂ was kept at 0.25 kgf / cm ² or less. Then, this pressure difference 0.25kgf / c
m ² was set as a reference value. During the operation, the pressure difference between the pressure measurement points P ₁ and P ₂ was 0.36 kgf / cm ² , which was higher than the reference value. From this pressure difference, it was determined that the furnace core was inactivated, and the oxygen concentration during the blowing was increased. As a result, the pressure loss in the furnace could be reduced in a short period of less than two weeks.

Example 2 As shown in FIG. 3, an increase in pressure loss in the furnace was observed. At this time, a sonde is inserted into the furnace and the pressure measurement points P ₁ and P
_When the pressure of ₂ was measured, it was 0.18 lower than the reference value.
A pressure difference of kgf / cm ² was detected. Therefore, it was determined that the gas flow in the upper part of the furnace was defective, and an action was taken by controlling the charge distribution. As a result, the pressure loss in the furnace returned to the initial level in a short period of about 12 days.

[0016]

As described above, in the present invention, the pressure difference between the core and the tuyere tip is detected, and the activity of the core is determined based on the pressure difference. A close relationship is established between the pressure difference and the activity of the furnace core, and the pressure difference between the inside of the furnace core and the tuyere tip can be easily detected.
Therefore, the inactivation of the furnace core is easily and quickly detected, and the deterioration of the furnace condition due to the furnace core inactivation is quickly predicted, so that a stable operation of the blast furnace with high productivity can be performed.

[Brief description of the drawings]

FIG. 1 shows that when the pressure drop in the furnace increases due to the core inactivation, the inactivation of the furnace core is detected in accordance with the present invention, and the change in the pressure loss in the furnace when the deterioration of the furnace condition is prevented beforehand. The graph shown

FIG. 2 shows an insertion state of a sonde into a blast furnace in an embodiment of the present invention.

FIG. 3 When the pressure loss in the furnace increases due to the deactivation of the furnace upper part, it is determined according to the present invention that the deactivated portion is located at the furnace upper part, and the furnace condition when deterioration of the furnace condition is prevented beforehand. Graph showing changes in pressure loss

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C21B 7/24 303 C21B 5/00 310

Claims (1)

(57) [Claims] 1. A sonde provided with a plurality of pressure measuring ports in a longitudinal direction is inserted radially into a furnace from a tuyere tuyere, a pressure difference between a furnace core and a tuyere tip is detected, and a pressure difference is detected based on the pressure difference. Detecting the activity of the blast furnace core by detecting the blast furnace core activity.