JPH0563522B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of operating a blast furnace, and more particularly, to a method of controlling hot air from the tuyeres of the blast furnace.

[Prior art]

The hearth of a steelmaking blast furnace is constructed mainly of carbonaceous refractories from the viewpoints of pig iron capacity, molten slag resistance, and cooling effect. In other words, the hearth side walls are all made of carbon blocks, and the bottom of the hearth is made up of an upper warbon block and a lower chamotsu brick.Recently, the upper warbon block or high alumina brick is made of a lower carbon block, and the entire structure is made of carbon blocks. A number of structures such as 3D structures have been adopted, and countermeasures have been taken in terms of materials to prevent erosion.

As means for controlling the amount of erosion of these furnace bottom bricks, the following various methods and problems with each method are listed. Namely, (1) Control method using TiO ₂ input amount This is a method of controlling the amount of bottom erosion by controlling the amount of TiO ₂ in the blast furnace charging material. However, according to this method, the amount of erosion at the entire hearth bottom is controlled, and cannot be carried out for each part.

(2) Control method using the amount of water sprinkled on the bottom of the furnace This is a method of controlling the amount of erosion by adjusting the amount of cooling water at the bottom of the furnace. However, according to this method, the work for adjusting the amount of watering is complicated, and the effect may not be significant.

(3) Method of adjusting the tuyere diameter This is a method of adjusting the hearth bottom diameter to change the balance of the air flow rate and adjust the activity of the hearth bottom below the tuyere. make the person blind. This method is very effective, but air rest must be performed in order to adjust the tuyere diameter.

There are various conventional methods such as the above, but each of these methods has the above-mentioned drawbacks, and improvements have been desired.

[Purpose of the invention]

The present invention provides a hot air control valve in the tuyere blowing branch pipe of a blast furnace, and by controlling the opening degree of this valve, the amount of air blown from each tuyere is controlled, and as a result, the amount of erosion on the bottom of the furnace is The purpose is to extend the life of the blast furnace and stabilize the furnace condition by performing arbitrary control for each blast furnace.

[Summary of the invention]

The present invention has been made to achieve the above object, and its gist is to provide a furnace bottom thermometer and a furnace bottom side plate thermometer at a plurality of locations around the circumference of a blast furnace, and to measure the furnace bottom temperature and the furnace bottom temperature, respectively. The bottom side plate temperature is measured, and if either the hearth bottom temperature or the hearth bottom side plate temperature rises or falls above the set value, the air flow rate from the tuyere above the rising thermometer is adjusted by the hot air control valve installed in the blower branch pipe. This is a blast furnace operating method characterized by control.

That is, the present invention provides a hot air control valve with a ceramic valve body above the blast furnace tuyere distance piece, and prevents the furnace bottom temperature and the furnace bottom side plate temperature provided around the bottom circumference of the blast furnace from being abnormal with respect to the set value. If approved, the hot air control valve is operated to control the amount of air blown.

This makes it possible to arbitrarily control the furnace bottom temperature during operation, thereby controlling the amount of erosion at the furnace bottom, making it possible to stabilize the furnace condition and extend the life of the furnace.

[Embodiments of the invention]

Embodiments of the present invention will be described based on the drawings.

Fig. 1 is a schematic diagram for explaining the present invention, Fig. 2 is a schematic diagram for explaining the present invention;
The figure is a side view of the tuyeres and the vicinity of the blower pipe, and FIG. 3 is a block diagram of the method of the present invention.

In Figures 1 and 2, 1 is a blast furnace, 2 is a furnace bottom, 3 is a hot air blast pipe, 4 is a hot air blast branch pipe, 5 is a hearth bottom thermometer provided around the furnace circumference, and 6 is a temperature of the hearth bottom side plate. A total of 7 is a hot air control valve provided in a hot air blowing branch pipe, and the valve body is mainly made of ceramic, such as a sintered body of silicon carbide (SiC), and has a material characteristic of particularly high high temperature strength.

Next, as shown in FIG. 3, the temperature is first measured using the furnace bottom thermometer 5 and the furnace bottom side plate thermometer 6 installed at multiple locations in the circumferential direction of the blast furnace 1. If either the furnace bottom temperature or the furnace bottom side plate temperature rises above the set temperature, the hot air control valve 7 adjusts the air flow rate of the tuyere 4 at the location where the temperature has risen, and the air flow of the blower branch pipe 4 is increased to a predetermined amount. Decrease the air volume while measuring it by differential pressure.

If the temperature also drops, the hot air control valve 7 is fully opened.

Furthermore, when the temperature rises to the second set temperature, the amount of air blown is further reduced to reduce the variation and lowering of the furnace bottom temperature.

Next, by the method of the present invention, the furnace bottom side plate temperature S,
Figure 4 shows the results of long-term temperature measurements at four locations: W, E, and N ports. In Figure 4, the 14th day ()
The temperature of the bottom side plate of the furnace S tuyere showed a rising trend, so the opening of the hot air control valve was set to 60%, but as the temperature rose further, the opening was changed to 40% in () and on the 18th day. As the temperature began to drop, the valve opening was returned to 100% on the 20th day ().

As a comparative example, _the furnace bottom side plate temperature S, W,
Figure 5 shows the results of long-term temperature measurements at four locations at E and N ports.

The tuyere S began to rise on the 6th day (), although bottom watering was strengthened, but it continued to rise () and TiO ₂
As a result of increasing the input amount from 5 kg/T. pig iron to 8 kg/T. pig iron, the temperature became a downward curve, but even after 27 days, the hearth temperature of the S tuyere remained the same as that of the other W, E, and N. The temperature was still high with a considerable temperature difference.

As is clear from the comparison of FIG. 4 and FIG. 5, according to the method of the present invention, the bottom temperature of the blast furnace has less variation, recovers quickly to the set temperature, and can be maintained at a low temperature, thereby extending the life of the blast furnace. It was possible to stabilize the furnace condition.

〔Effect of the invention〕

The blast furnace operating method according to the present invention makes it possible to maintain the furnace bottom temperature at a low temperature and to arbitrarily control erosion in different parts of the furnace bottom, thereby extending the blast furnace life and contributing to stabilizing the furnace condition. This is a useful method.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram for explaining the present invention, Fig. 2 is a schematic diagram for explaining the present invention;
The figure is a side view of the tuyeres and the area around the blast pipe, FIG. 3 is a block process diagram of the method of the present invention, FIG. 4 is a graph of the furnace bottom plate temperature in the method of the present invention, and FIG. 5 is a graph of the furnace bottom plate temperature in the conventional method. DESCRIPTION OF SYMBOLS 1... Blast furnace, 2... Hearth bottom, 3... Hot air blast pipe, 4... Blower branch pipe, 5... Hearth bottom thermometer, 6... Hearth bottom side plate thermometer.
The same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Install hearth temperature gauges and furnace bottom side plate thermometers at multiple locations around the circumference of the blast furnace, measure the hearth bottom temperature and furnace bottom side plate temperature, respectively, and measure the hearth temperature and the furnace bottom side plate temperature. A method of operating a blast furnace characterized in that when any one of them rises or falls above a set value, the amount of air blown through the tuyere above the rising thermometer is controlled by a hot air control valve provided in a blowing branch pipe.