JPS60235986A - Method of cleaning wall surface of kiln - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for efficiently cleaning the wall surface of a steel furnace such as a coke oven.

(Prior art and its problems) In a steel kiln, cleaning the wall surface while the furnace is in operation is important to ensure stable operation of the furnace, and
It is also necessary as a pre-treatment for repairing damaged wall areas (for example, spraying) to increase the repair effect.

For example, in a coke oven, carbon adheres to almost the entire wall surface of the coking chamber, forming a layer. The formation of this layer narrows the internal dimensions of the furnace, causing clogging during coke cake extrusion work. Therefore, in order to remove this adhered carbon, we periodically oxidize and burn off the carbon, depending on the operating conditions. Because the carbon deposits are wedge-shaped, they are difficult to remove. Conventionally, this was done by blowing air or 01 gas onto the carbon deposited surface to accelerate oxidation, or by pushing it down with a long steel bar. I was dealing with it.

However, the effect of such a method in shortening the void time was not satisfactory.

In addition, when a void is detected, the damaged wall area where cracks or defects have occurred is repaired at the same time (usually by spraying), but as a pretreatment process, old repair materials and joint materials that are likely to fall off are also repaired. The wall surface is cleaned by knocking off the adhering carbon with a steel bar.

However, the above-mentioned cleaning work conventionally relied on manual means, which took a long time, resulting in excessive cooling of the furnace, and in addition, the finished product was incomplete. Additionally, in order to improve the adhesion of the repair material, there is a method of scraping off the deteriorated wall surface with an air hammer, but while this method is effective in terms of the adhesion of the repair material, it does not damage the furnace wall more than necessary. From the perspective of furnace body strength, since it will be scraped,
It is not recommended to perform this repeatedly.

On the other hand, in smelting furnaces such as converters, ladles, or tap sluices that hold molten metal, the remaining molten metal cannot be completely exhausted and solidifies on the lining surface or melted recesses. Although it is mechanically peeled off, it has the disadvantage that it tends to damage the wear bricks at this time. When repairing the wall, the material that has solidified on the wall surface will not peel off even if subjected to a slight thermal shock, so the repair material may be overlaid in that state. Then, when the furnace is restarted, the remaining solidified metal melts again, causing the repair material to peel off from the inside, and there is no repair effect at all.

In other words, conventional cleaning methods for kilns do not require workers to perform heavy, high-temperature work, but they do provide a clean furnace wall surface and minimize damage to the base material. ,
It was also not satisfactory as a pretreatment method before repairing the furnace.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems.
The purpose of the present invention is to provide a method for cleaning the wall surface of a kiln that can ensure a good finished wall surface, minimize damage to the lining bricks during the above-mentioned work, and furthermore prevent damage from occurring due to furnace cooling. .

(Structure of the Invention) The present invention is characterized in that the gas ejection speed at the ejection port is 50 m/r, ee
In this manner, the plasma jet stream with a gas temperature of 5000°C or higher at the core of the jet nozzle is brought close to or in contact with impurities attached to the lining bricks of the kiln, and the impurities are removed from the lining bricks. This is a method for cleaning the wall surface of a kiln, the gist of which is to melt, cut, or peel off the lining surface of the furnace.

Here, the reason why the gas ejection velocity at the ejection port of the plasma jet airflow is set to 50 m/- or more and the gas temperature at the ejection port core is set to 500°C or more is that the plasma jet airflow is made to have a conical shape. In order to prevent excessive heat from being applied to the kiln wall surface in the eastern part of the prefecture, and to melt impurities attached to the kiln wall in a short time and minimize the impact on the kiln wall as much as possible. It is.

(Example) The present waste method 1 will be described in detail below based on an example.

The method of the present invention uses a plasma jet stream (hereinafter referred to as "plasma flame") to melt, burn, and burn carbon, slag, or metal that is widely adhered to the wall of a steel kiln such as a coke oven in a short time. This method involves cutting or peeling.

In other words, as shown in Table 831 below, compared to other heat sources, plasma flame can easily generate temperatures that are -1 - digit higher;
The degree of heat concentration is high; ∎ The flow rate can be controlled to subsonic speed; ∎ It can be generated using gases of various components; ∎ The generator is simple and the cost required to generate a unit of heat is low. .

Table 1! Therefore, the method of the present invention uses a plasma flame. For example, Ar gas is used as the primary gas, and one or a mixture of 2 m of Hl or He gas is used as the secondary gas.

Then, the flow rate ratio of the primary gas and the second gas is set to 1, for example.
A plasma flame is generated and used in a range of 0:0 to 723.

11 The primary gas is determined primarily to ensure a high temperature, high velocity flame, and the secondary gas is determined primarily to ensure a high heat landscape.
The present invention is not limited to the embodiments described above as long as it meets this purpose.

In addition, the flow rate ratio of the primary gas and the secondary gas is such that the generated plasma flame has a high temperature and high velocity, that is, a sharp conical shape with a temperature of 5000°C or more at the core of the jet nozzle and a diameter of 50 m/- or more at the jet nozzle. In the above-mentioned embodiment, the ratio of the primary gas, Ar gas, to 70% or more (the secondary gas, ``ha'' or He gas, was mixed with one type or 2 seconds). (less than 30), the above conditions are satisfied.

A plasma flame that satisfies the above conditions has approximately 2
The plasma flame is maintained at a temperature of 1,000° C. and is brought into contact with deposits, such as carbon, attached to the lining bricks of the kiln, thereby melting and removing the deposits. Also,
Carbon attached to the wall of the coke oven carbonization chamber (melting point 6
000℃) has a thickness of several millimeters or more, but in the method of the present invention, by adjusting the distance between the plasma flame and the wall surface as appropriate, it is also possible to melt or cut the deposits. It is. Furthermore, according to the method of the present invention, methods such as adjusting the distance between the plasma flame and the wall surface to promote peeling due to the difference in thermal expansion between the deteriorated layer and the healthy layer on the wall surface or to promote melting and scattering can be adopted.

The basic configuration of the apparatus for carrying out the method of the present invention is 9. It was disclosed in Japanese Patent Publication No. 58-49889. That is, among the kiln wall repair equipment disclosed in the above publication, the equipment including the equipment M and its control system, the repair material feeding route, etc., the tamashi plasma gun operating equipment a and its cooling equipment. It is sufficient to use one constructed from the following.

(Specific Example 1) In a coke oven A (furnace capacity: 48.6 n/), the extruder flow value (pusher drive current during cake extrusion) exceeded the allowable value during operation at a load factor of 115 inches. Therefore, when air steaming was immediately started, the precipitated crab bons had formed an adhesion layer on both side walls of the central part of the carbonization chamber, each having a thickness of approximately 5 m, a height of 3 m, and a length of k<4 m. So, empty hole start 5
After an hour, the tip of a plasma flame (length 45 cm) was brought into contact with the adhesion layer at intervals of 500 mm for each of i, minor, and lateral directions, and the layer was cut into a lattice shape. As a result, the cut adhered carbon layer warped from the cut point and completely peeled off 10 hours after the opening. On the other hand, the adhering carbon layer on the wall surface of one side, which had been left untreated, began to peel off after 3:18 p.m. of the opening. In addition, in this specific example, Ar gas: 50t
/m, N, gas: using 5t/1Ith gas, 10
The experiment was conducted using a plasma flame generated at 9000° C. and 2400 cm with an output current of 0 QA.

(Specific Example 2) In converter B (furnace capacity: 150 mm), assimilation of slag occurred at the bottom blowing tuyere portion in a volume of approximately 201 mm. Therefore, with the furnace tilted 95 degrees, a plasma gun housed in a water-cooled case was inserted, the tip of the plasma flame (length 50 m) was brought into contact with the solidified deposits, and a pattern was drawn that drew a square with one side of 1005 m. While the plasma gun was not activated (2 ml-b), the solidified deposits were melted and flowed out to the side wall.

No, when the method of the present invention was used, it was possible to return to the operating line after about 1 hour.

On the other hand, in such cases, long steel bars are used and the solidified deposits are removed manually, but this method often damages the supporting bricks around the siding, so usually the furnace is first removed. After removing it from the Sks line, we had to break the tuyere bricks and replace them, and then return them to the operating line, which took about half a day. In this specific example, Ar gas: 50t/-1-1N2 gas: 15t/1
Using IiI gas gold, with an output current of 750A, 700
The experiment was conducted using a plasma flame generated at 0° C. and 2000 mAst.

(Effects of the Invention) As described above, according to the method of the present invention, the furnace can be cleaned in a short FQ without requiring the operator to perform long-term harsh wiping streaks or charcoal work. This invention has the great effect of keeping the damage to as small as possible.

Claims (1)

[Claims] (1) A plasma jet stream with a gas ejection speed of 50 m/m or more at the nozzle and a gas temperature of 5000°C or more at the nozzle core is attached to the lining bricks of the kiln. A method for cleaning a furnace wall surface, the method comprising: approaching or contacting impurities present in the furnace wall, and melting, cutting, or peeling off the impurities from the lining surface of the lining brick.