JPS596888B2 - Method for detecting deposits on blast furnace walls - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting deposits on the wall of a blast furnace, and more specifically, the present invention relates to a method for detecting deposits on the wall of a blast furnace, and more specifically, detects a layer of deposits such as alkali metals such as zinc and carbon that are firmly formed on the wall of a blast furnace during operation. The present invention relates to a method for detecting deposits that can detect the position, thickness, etc. of the deposits.

In general, during the operation of a blast furnace, a layer of deposits called wall deposits may occur and grow on the furnace walls.

This deposit contains various components such as alkali metals such as zinc, metallic iron, and carbon, and various considerations have been made regarding the cause of its occurrence and the growth process, but it has not yet been definitively determined. Not yet.

However, if this deposit adheres to the furnace wall, the profile inside the furnace changes, leading to uneven conditions inside the furnace.

If it grows further and falls off the furnace wall for some reason, it will cause poor furnace conditions such as cooling at the bottom of the furnace.

Therefore, for blast furnace operation, it is very important to detect the presence, location, thickness, etc. of deposits.

The following methods are usually used to measure the presence or absence of deposits on the blast furnace wall.

(1) Method of actually measuring the thickness of deposits by polling the inside of the furnace from the outside of the steel shell during wind breaks.

(2) The presence of deposits deteriorates heat transfer from the high-temperature parts of the furnace, resulting in a decrease in the furnace wall brick temperature or iron skin temperature, and a method of detecting this temperature decrease.

(3) Since alkali metals such as zinc are thought to be a contributing factor to the formation of deposits, the amount of these metals in the charge and the amount of these metals in the discharged dust are compared and A method of determining the amount of accumulation and determining that there is a deposit when the amount of accumulation increases.

However, among the above measurement methods, method (1) is difficult to measure during operation, and requires a great deal of labor and time even during wind breaks.

In method (2), the cause of the decrease in the furnace wall temperature is not only deposits, so the decrease in temperature does not immediately lead to the adhesion of deposits, and the heat transfer properties of the deposits are unknown, so the thickness is It cannot be measured accurately and can only be estimated.

Method (3) cannot accurately measure both the amount of metals charged and the amount of metal discharged, so it is not possible to accurately calculate the amount accumulated in the furnace. Furthermore, it is impossible to estimate the location and thickness of the deposit.

The purpose of the present invention is to solve the above-mentioned drawbacks, and specifically, to provide a method that can accurately detect the presence or absence of deposits, as well as detect the position and thickness of deposits using a simple method even during operation. suggest.

That is, in the method of the present invention, a thermometer is inserted into the blast furnace wall through a through hole penetrating into the inside of the furnace, and the tip of the thermometer is made to protrude a certain length inside the furnace. It is characterized by continuously measuring temperature changes that fluctuate periodically corresponding to Method for detecting deposits on blast furnace walls.

The method of the present invention will be explained in detail below with reference to the drawings.

Note that FIG. 1 is an explanatory diagram of an example of carrying out the method of the present invention, and FIG. 2 shows periodic fluctuations in temperature corresponding to the raw material charging cycle when the temperature is measured as shown in FIG. 1. FIG. 3 is a graph showing an example of the formation of deposits on the blast furnace wall; FIG. 4 is a graph showing the temporal change in temperature in the case shown in FIG. 3; The figure is a block diagram of an example of an apparatus for carrying out the method of the present invention.

First, in FIG. 1, reference numeral 1 indicates the furnace wall, 2 indicates the steel shell, 3 indicates the thermometer, and 4 indicates the protective tube for the thermometer. A thermometer 3 is inserted into the through hole 5, and the thermometer 3 is sealed with gas by the tube seat 6.

Inside the blast furnace, the charge falls in the direction of the solid line arrow, and the gas in the furnace rises in the direction of the dotted line arrow.

In addition, the coke layer 7 and the ore layer 8 are charged alternately in layers, and when the coke layer 7 and the ore layer 8 descend smoothly, the temperature measured by the thermometer 3 will increase as shown in FIG. It appears as periodic changes in temperature.

Each charge temperature change corresponds to the charging period, which is usually about 7 to 10 minutes, and the temperature changes shown in FIG. 2 also appear at the same period.

That is, in a blast furnace, coke and ore are normally charged from the top of the furnace, and each forms a layer and descends.

On the other hand, hot air blown from the lower part of the furnace flows through each of these layers in sequence and heats the coke and ore.

However, ore and coke have different particle sizes and heat capacities, and the coke temperature is higher than that of ore.

Therefore, as mentioned above, when a thermometer is inserted into the furnace through the through hole that penetrates the furnace wall and the temperature inside the furnace wall is measured, the temperature of the gas flowing through the tip of the thermometer as well as the temperature of the gas flowing through the tip of the thermometer are measured. The temperature of the charged solid charge is also detected; in particular, due to the temperature difference between the ore and the coke, periodic temperature changes are detected as these layers pass through the tip of the thermometer.

Next, periodic temperature changes are detected steadily as described above, and while this state continues, for example, as shown in Figure 4, the periodic changes may disappear, and this disappearance may occur. The presence of deposits can be detected when they occur.

As shown in FIG. 3, when deposits 9 occur on the furnace wall 1, the descent of charges such as coke and ore is obstructed in this area.

At this time, the tip of the thermometer 3 is buried in the deposits 9, so the temperature difference between the coke and the ore cannot be detected.
Temporal changes in the furnace temperature do not show periodic changes corresponding to the charging cycle, and are approximately constant.

In this case, if the protruding length l of the thermometer 3 from the furnace wall is set to a predetermined value, the periodic fluctuations that coincide with the charging cycle will disappear when the tip of the thermometer 3 is inside the deposit 9. In other words, the deposit 9 is the length l of the thermometer inserted into the furnace.
This means that the deposit 9 has grown to a certain extent, and the thickness of the deposit 9 can also be detected.

Note that periodic changes in the temperature measurement values can be detected by recording them on a recorder and visually observing the recorded results, but it is also possible to determine them more quantitatively and automatically.

Generally, the strength S(f) of a periodic component with a period f of a certain varying amount x (t) can be calculated by the following equation (1).

Here, R(t) is an autocorrelation function of the variable x (t) and is expressed as.

T is the observation time. In addition, since the charging period can be calculated from the signal from the charging device, the magnitude of the fluctuation component S(f) of the period f equal to this charging period is monitored, and for example, the 5th
It may be automatically detected by the device shown in the figure.

That is, a temperature signal 11 is sent from a thermometer 3 attached to the wall of the blast furnace 10 as shown in FIG. 1 to a periodic component calculation device 12.

On the other hand, a charging signal 14 issued from a charge charging device 13 attached to the blast furnace 10 is input to a charging cycle calculation device 15 .

The detection device 16 receives the periodic component intensity signal 1 7 (corresponding to S (t) in equation ()) from the periodic component device 12 described above.
and the charging cycle signal 1 issued from the charging cycle calculation device 18.
9, the periodic component S ( f'
) 20 is detected and sent to the comparator 21.

The comparator 21 compares the preset value 22 and the periodic component S.
(f') 20 is compared, and when S(f') becomes smaller than the set value 22, a deposit adhesion alarm 23 is issued to the operator.

In summary, the method of the present invention effectively utilizes the thermal properties of the charge in the blast furnace to detect the presence, thickness, etc. of deposits, and these can be detected even during operation. It is possible.

In addition, it is possible to understand changes in the furnace profile caused by deposits, and take appropriate operational actions to equalize the reaction in the circumferential direction of the furnace or to remove deposits. This greatly contributes to the stable operation of blast furnaces.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of implementing the method of the present invention, and FIG. 2 is a graph showing an example of periodic fluctuations in temperature corresponding to the raw material charging cycle when the temperature is measured as shown in FIG. 1. , FIG. 3 is an explanatory diagram of the manner in which deposits are formed on the blast furnace wall, FIG. 4 is a graph showing the temporal change in temperature in the case shown in FIG. 3, and FIG. 5 is an example of an apparatus for carrying out the method of the present invention. FIG. Code 1...Furnace wall, 2...Iron shell, 3...
...Thermometer, 4...Protection tube for thermometer, 5.
...Through hole, 6...Pipe seat, 7...
・Coke layer, 8...Ore layer, 9...
Deposit, 10... Blast furnace, 11... Temperature signal, 12... Periodic component calculation device, 13...
...Charging device, 14...Charging signal, 15...
...Charging cycle calculation device, 16...Detection device, 17...Periodic component intensity signal, 18...
・Charging cycle calculation device, 19...Charging cycle signal,
20... Periodic component S(f'), 21...
・Comparison device, 22...Setting value, 23...
・Adherence alarm.

Claims (1)

[Claims] 1. A thermometer is inserted into the blast furnace wall through a through hole that penetrates to the inside of the furnace, and the tip of the thermometer protrudes a certain length inside the furnace. A method for attaching a wall of a blast furnace characterized by continuously measuring temperature changes that fluctuate periodically, and confirming and detecting the presence of deposits when the periodic temperature changes disappear and the value becomes approximately constant. Kimono detection method.