JPS62278217A - Lance inlaying thermocouple for controlling slag level - 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 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a blowing lance for controlling the slag level during rice cooking in a steelmaking furnace.

(Prior art) In steelmaking furnaces such as top-blown or top-bottom blown converters, in order to improve productivity and quality, it is necessary to grasp the progress state of the refining reaction inside the furnace and perform appropriate control according to the state. There is a need.

Therefore, in order to control the inside of the furnace, for example, when measuring the height of molten metal maple and slag in the furnace, as in JP-A-56-151881, the thermal displacement of a rod covered with a refractory has been measured. It has been proposed to detect the slag height.

However, even if this device is used, the consumption rates of the refractory and the rod do not necessarily match, and it is difficult to say that normal temperature detection can be performed depending on the consumption status of the refractory. That is, the heat transfer energy to the heat detector differs depending on the thermal conductivity and length of the rod.

This method has the disadvantage that the inner surface of the furnace, which should be measured, is melted and damaged, so it is not possible to embed a thermocouple in the surface.

In addition, when predicting all the slopping in a converter as in Japanese Patent Application Laid-open No. 55-38915, the impact force of the slag splatter/yu acting on the hanging end of the chain and the buoyant force due to slag forming can be detected and grasped. It has also been proposed to do so.

However, even with this method, a difference in moment occurs depending on the detection level, and due to the weight of the slag that has solidified on the chain, even if the same impact force or buoyancy force is generated, the difference in inertia force and the strain value will decrease. Therefore, measurement errors tend to increase. In addition, there is a drawback that time loss occurs during operation due to the loading and unloading of the equipment, making it impractical.

(Problems to be Solved by the Invention) The present invention is capable of detecting the slag level in the furnace with high ellipticity, which is a drawback of conventional slag level detection as described above, and also enables reliable grasping of the state inside the steelmaking furnace. Another object of the present invention is to provide a lance for controlling a slag level that can continue detecting a slag level for a long period of time and can perform a detection operation quickly.

(Means for Solving the Problems) The present invention provides a molten metal blowing acid lance in which a round flow path is provided inside and the outer periphery of the oxygen flow path is surrounded by a cooling water flow path, in which the blowing acid lance is cooled. A thermocouple embedded lance for controlling a slag level is characterized in that a plurality of thermocouples are embedded in an outer pipe of a water flow path.

The thermocouple embedded lance for controlling the nug level according to the present invention will be described below.

First, the present inventors found that direct detection using a lance used for blowing acid is the most efficient way to control the slag level while utilizing the conventional smelting process. Furthermore, it has been found that the cylindrical outer surface shape of the acid blowing lance and the long length inserted into the furnace make it possible to accurately grasp the entire bath surface even under extremely fluctuating conditions inside the furnace. Ta.

The present invention has been made based on the above-mentioned knowledge, and will be described in detail below based on the embodiment shown in the drawings.

Fig. 1 shows a sectional view near the head of the thermocouple embedded lance for slag level control of the present invention, Fig. 2 shows a partially enlarged view of part A in Fig. 1, and Fig. 3 shows the thermocouple embedded part. An enlarged cross-sectional view is shown.

The acid blowing lance 1 includes, for example, a cooling water flow path '7a which has an appropriate inner diameter and is composed of an oxygen flow path 4 communicating with the nozzle 3 of the head 2 at the tip, a partition pipe 5 surrounding the oxygen flow path 4, and an outer pipe 6; '7
b is provided.

The cooling water side of the outer tube 6 of this lance 1 is made of, for example, Cu-Ni.
, general thermocouples N-1 to N-3 made of various materials such as Cu-iron or Yamakasa-platinum rhodium are buried, and the opposite side of the thermocouples N=1 to N-3 is buried. Thermocouple M is similarly buried at approximately the same level as thermocouple N-i. The thermocouples N-1 to N-3 and M are buried within a thickness of % to %t with respect to the thickness t of the outer tube 6, as shown in Figs. 2 and 3, and the conductors are cooled. The water advances through the water flow path 7b and extends to the outside of the acid blowing lance 1.

In addition, a plurality of thermocouples N- are embedded in the outer pipe 6 of the acid blowing lance 1.
1 to N-3 are provided sequentially from the upper part of the head 2 toward the furnace mouth at appropriate intervals in the height direction, and at least one opposing thermocouple M is provided with thermocouples N-1 to N-3. and at least 90° or more or 360'/H for hJ hole lances
Provided so that the circumferential surface can be measured at intervals of .

In this way, by setting the angle to 90' or more or 360°/N, it is possible to accurately grasp the flow and ejection conditions in the furnace.
For the same surface within the above range, the accuracy is greatly reduced.

Next, by using the acid blowing lance 1 configured as described above, the following situation can be completely understood. First, as shown in FIG. 1, thermocouples N-'1 to N-3 buried in the right direction measure the slag height displacement as follows.

Thermocouple N-2 not immersed in slag shown in Figure 4
The temperature measurement f[T+ is the thermocouple N− immersed in the slag.
It shows a value lower than the measured temperature value T2 of No. 1. Next, when the slag level rises and thermocouple N-2, which was not previously immersed in slag, is immersed in slag, the temperature value measured by thermocouple N-2 changes as shown in Figure 5. occurs, and it is possible to recognize changes in the slag level both upward and downward. Also, the rate of increase in the slag level can be determined by the time difference at this time.

On the other hand, when the slag level above falls, the opposite phenomenon occurs and the sinking of the slag level can be detected.

Next, the functions of thermocouples M and N-1 buried at the same height will be explained with reference to FIGS. 6, 1, 7, and 8.

When the thermocouple is not immersed in the slag, thermocouple M and N-1
naturally shows a low temperature value. (Fig. 6) Next, when the slag surface rises in an inclined state, the thermocouple is attached to one side (for example, thermocouple M
) is immersed in the slag while the other is not, resulting in a difference in temperature measurements. (In the 7th figure, when thermocouple N-1, which was not immersed in the slag, is immersed in the slag, the temperature becomes the same. You can know.

Next, FIGS. 9 and 10 show the measurement results of the skin temperature of the outer tube 6 using the embedded thermocouple lance. In FIG. 9, 'PA' indicates the temperature of the outer tube shell where the embedded thermocouple is cooled by water, and 1'B indicates the temperature measured when the embedded part of the thermocouple is immersed in the slag layer. In addition, part a shows a state in which the water-cooled outer tube 6 is buried in the slag layer and the surface temperature gradually increases from the bottom of the lance due to forming of the slag in the steelmaking furnace. When the forming slag subsides, the outer tube 6 buried in the slag layer is exposed from the slag layer, and the temperature of the outer tube shell gradually decreases from above the lance. Therefore, the slag level at the actual time during the blowing process can be detected by the measurement described above.

Next, FIG. 10 shows that the slag in the steelmaking furnace was stirred violently and was not minked into layers. In other words, the temperature rise pattern of each buried thermocouple overlaps, and the temperature rises and falls regardless of the buried position of the thermocouple.

This is because slopping slag directly scatters and adheres from the molten metal surface to the part where the thermocouple is buried, increasing the temperature detected by the thermocouple at that location.Next, the slag adhering to the lance cools or peels off, causing the detected temperature to drop. Indicates that the aspect is repeated.

The slopping situation in the furnace can be monitored using the pitch of this temperature change pattern and the temperature change formula. It is also expected that the slag and base metal adhering to the lance surface will not peel off but will adhere and solidify, which may cause measurement errors in the lance surface temperature, but the current measurement is based on the temperature measured at the initial stage of blowing. If the temperature value and the q relative value are used for management, the slag level or forming speed drum can be detected in the same manner as described above.

(Example) Next, FIG. 11 shows the blowing results obtained by controlling the slag level using the lance of the present invention.

As shown in Figure A in Figure 11, slopping occurred due to disturbances even though the operation was carried out according to the standard confectionery method. Therefore, we tried to suppress this slopping by changing the acid supply lid and other equipment.

Thereafter, when 60% of the blowing time had elapsed, as shown in part B, the slag level increased and slopping occurred along with this increase. Therefore, the slag level was gradually stabilized as a result of controlling the slag level by controlling the speed of oxygen supply, the height of the lance, and adding an auxiliary material (reduced detergent).

In this way, by using the blown acid lance developed by the present invention, it is possible to suppress sysloping and abnormal slag forming, and also to control the slag level to an arbitrary height using multiple buried thermocouples. It has also become possible to improve the refining aptitude of p, s, etc.

(Effects of the invention) As described above, by using the lance of the present invention, (
1) Management of slag level, (2) Control of slag level becomes possible, and as a result, effects such as (1) improvement in yield, (2) high efficiency operation, and (3) cost reduction can be achieved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view near the head of the thermocouple buried lance for slag level control according to the present invention, Figure 2 is a partially enlarged view of section A in Figure 1, and Figure 3 is an enlarged sectional view of the thermocouple buried part. , Figure 4 (
al (bl, Figure 5 (a) (bl is a diagram showing the presence or absence of slag immersion of the hot soaked pair and temperature change, Figure 6 (a). (b), Figure 7 (a), (b), Figure 8 (al,
(Di is a diagram showing the temperature change depending on whether or not slag is immersed in the opposing hot-soaked pair. Figures 9 and 10 show the measurement results of the steel skin temperature using the hot-soaked pair buried in the outer pipe of the crawler. Figure, 1st
FIG. 1 is a schematic diagram showing an example of operation according to the present invention. 1... Lance 2... Head 3... Nozzle 4... Oxygen flow path 5... Partition pipe 6... Outer tubes '7a, 7b... Cooling water flow path N-to N-3... Heat-soaked pair M... Opposing heat-soaked pair Fig. 1 Ame 3'A Fig. 4 Tatsumi I @ % Bi 5- Hiaki → Figure 9 Gin [ Figure 10 Gin

Claims (1)

[Claims] In a molten metal blown acid lance that has an oxygen flow path inside and the outer periphery of the oxygen flow path is surrounded by a cooling water flow path, a plurality of thermocouples are embedded in the outer tube of the cooling water flow path of the blown acid lance. An embedded thermocouple lance for slag level control characterized by: