JPS61149411A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To exchange systematically a tuyere of a blast furnace when the furnace is operated by blowing powder from the tuyere, by embedding thermometers in the tip of the tuyere and detecting the friction state of the tuyere from the indicated values so as to find the danger of damage of the tuyere in the early stage. CONSTITUTION:Thermometers 11 are embedded in the tip of a tuyere 1 of a blast furnace at several positions close to a cooling water hat 8 in the form of a ring. Temps. Ti indicated by the thermometers 11 are continuously compared with a set temp. To, and in case of Ti>To, the blowing of powder is automatically stopped. Thus, the rate of operation of the blast furnace by the blowing of powder is increased and the blowing efficiency is also increased.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of operating a blast furnace, particularly a method of controlling the operation of a blast furnace by detecting the wear status of a tuyere in a blast furnace operation in which powder is injected through the tuyere. Regarding.

[Conventional technology]

Recently, as blast furnaces have become larger, advances in blowing technology have
There are remarkable features such as high-temperature air blowing, dehumidification, humidity-controlled air blowing, oxygen/nitrogen enriched air blowing, and high-pressure operation with fuel injection.

For this purpose, high-temperature hot air, oxygen/nitrogen enriched air, fuel, etc. are blown into the blast furnace through the tuyeres shown in FIG. FIG. 1 is an explanatory diagram of the blast furnace tuyere.

In the blowing tuyere section shown in Fig. 1, 1 is a normal tuyere, 2 is a fuel injection nozzle, 3 is a large tuyere, 4 is a tuyere support made of cast iron or cast steel, 5 is a blast furnace shell, and 6 is a stamp. , 7 is a tuyere brick, and 8 is a tuyere cooling water passage. The large tuyere 3 and the normal tuyere 1 are usually made of pure copper, and the normal tuyere IK has a structure in which cooling water of 600 to 500z/- flows through the cooling water passage 8 to extend its life. On the other hand, the tip and outer surface of the tuyere are coated with a heat-resistant material such as stamp material 6.

These tuyeres are often worn out by the falling of the charge inside the furnace, and there is no way to detect damage other than by checking for air bubbles that form in the tuyere cooling water. There is almost no way to detect this in advance, and the solution has been to periodically replace the tuyeres.

On the other hand, recently, techniques have been used to directly inject pulverized coal, limestone, iron oxide, mill scale, etc. into blast furnaces.

For example, Japanese Patent Publication No. 58-56721 discloses that pulverized coal and iron oxide or reduced iron are blown into the blast furnace through the blast tuyere.
A method for operating a blast furnace at low temperature by mixing pulverized iron is disclosed, which is characterized by reducing the 81 content in the tapped pig iron.

In blast furnace operation where powder is injected through the tuyeres, it is necessary to solve the problem of tuyere wear.

[Problem that the invention seeks to solve]

As mentioned above, when powders such as pulverized coal, limestone, iron oxide, and mill scale are directly injected into the blast furnace tuyeres, the tuyeres are usually worn out by these powders, and the tuyere cooling water infiltrates into the furnace. The furnace cools down rapidly, forcing a sudden shutdown. Therefore, in blast furnace operations in which powder is injected from the tip of the tuyere, the internal wear of the tuyere is usually detected in advance, and powder injection operations are carried out. There was a demand for the development of a technology that would prevent tuyere damage by stopping only the tuyeres.

[Means for Solving the Problems] The present invention has been made in response to the above-mentioned requests. The present invention provides several temperature gauges arranged in a ring shape near the cooling water passage at the tip of the inner surface of the tuyere. bury the thermometers, and continuously measure the changes in the readings of these thermometers.If an abnormality is detected at an early stage based on the readings of the thermometers, only the powder transportation can be stopped to prevent tuyere damage. It is intended to prevent

Figure 2 is a front view of the normal tuyere inlet, where 9 is the outer circumference of the tuyere, and 1
0 indicates the inner circumference of the tuyere.

As shown in FIGS. 1 and 2, thermometers 11 are embedded in several ring shapes near the cooling water passage 8 on the inner surface of the tuyere 1, and the indicated value of the shark thermometer 11 is used to detect the temperature of the tuyere. The degree of wear is determined and the powder blown into that tuyere is automatically or manually stopped.

Fig. 3 is a block diagram for explaining an embodiment of the present invention that monitors the tuyere wear condition and automatically stops powder injection. The normal temperature Ti is 100 to 200℃, and the set temperature To
For example, as shown in Figure 5,
The indicated value TI of the thermometer 11 is continuously set (compared with 1jiTo, and when TI)To, the powder injection is automatically stopped.

Incidentally, the Ti may be monitored and the injection of the "C" body soft body may be manually stopped.

〔Example〕

As shown in Figures 1 to 3, six thermometers for monitoring the wear status of the tuyere are embedded in a ring shape near the cooling water passage 8 on the inner surface 10 of the tuyere, and the set value To = 500 to 900°C. When the powder injection operation was carried out for three months with the following settings, the results were as follows.

Method of the present invention Conventional method Setting values 500℃ 700℃ 900℃
-Number of blowing stops 5 4 4 -Sudden wind breaks #0 01 5 By the method of the present invention, sudden wind breaks caused by blowing K into the powder were reduced compared to the conventional method, and it became possible to carry out planned wind breaks.

〔Effect of the invention〕

According to the method of the present invention, the danger of tuyere damage can be detected early, the tuyere can be replaced in a planned manner, and sudden wind shutdowns can be prevented, so powder injection operations into blast furnaces can be improved. 0, which improves the operating rate and increases efficiency.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the blowing tuyere section, Fig. 2 is a front view of the normal tuyere inlet section, and Fig. 3 is a block diagram for explaining an embodiment of the method of the present invention. 1 is usually the tuyere,
3 is the large tuyere, 8 is the cooling water passage, 11 is the thermometer, TI is the normal temperature, and To is the setting for the 1st shift. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] During blast furnace operation in which powder is injected from the tip of the blast furnace tuyere, multiple thermometers are embedded inside the tip of the tuyere, and the readings from the thermometers are used to detect the wear status of the tuyere and control the injection of powder. A blast furnace operating method characterized by: