JPS62238308A - Temperature measuring method for bottom part of blast furnace - Google Patents

Abstract

PURPOSE:To easily measure the continuous temp. distribution at optional time on the boundary of the meridian section of a furnace bottom part by forming a passage having both ends opened to the outside of the furnace to the inside of the refractories from the furnace bottom to side wall and moving a temp. measuring sensor. CONSTITUTION:The passage 14 to be conducted with the temp. measuring sensor 12 is formed between the refractories 2 in the side wall part of the furnace bottom and a cooler 9 as well as the refractories 2 right above a surface plate 10 at the furnace bottom. This temp. measuring instrument 11 is remotely operated to wind or unwind the sensor 12 by a winder 13 and to freely move the sensor in the passage 14, by which the temps. of the refractories 2 in various parts are detected. The continuous temp. distributions at optional time from the center of the furnace bottom to the shell part of the side wall or from the shell part of the side wall to the shell part of the side wall on the base of the furnace bottom and from the part right under tuyeres 8 to the furnace bottom plate 10 on the side wall of the furnace bottom are measured on the optional meridian section of the furnace bottom refractories 2.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for measuring the temperature at the bottom of a blast furnace, and in particular to a method for measuring the temperature at the bottom of a blast furnace, particularly for corrosion of refractories in furnaces such as blast furnaces, which have high-temperature molten material inside and cannot directly monitor the inside. The present invention relates to a measurement method for estimating with high precision the distribution of a coagulated layer that ebbs and flows on the eroded surface of refractories, and improving the precision of control measures aimed at stabilizing operations and extending the life of the furnace. In addition, 1 unreleased item! The term "blast furnace" collectively refers to a furnace that contains a high-temperature molten material to promote a reaction, such as a blast furnace, electric furnace, or glass melting furnace.

[Conventional technology]

A blast furnace will be described below as a representative example of a blast furnace.

Increasing the size of blast furnaces and operating conditions in pursuit of crystal productivity in recent years
・R-butylation accelerates the wear and tear of heavy materials at the bottom of the furnace and shortens the life of the blast furnace. In blast furnace operation under conditions of low economic growth, it is important to maintain stable operation, extend the life of the blast furnace, and reduce the unit price of pig iron.

In order to ensure stable operation and extend the life of this blast furnace.

First of all, it is essential to constantly monitor the corrosion status of the bottom refractory during blast furnace operation and take prompt and accurate protection measures for the corroded areas.
It is lacking.

At the same time, we constantly monitor the distribution of the solidified layer, which is a mixture of hot metal, coke, brick fragments, and other charges, that repeatedly forms and disappears on the eroded surface of the refractory due to the protection measures.
Quantifying refractory protection measures and controlling the solidified layer thickness and layer thickness distribution are also important issues.

In other words, from the standpoint of protecting the refractory, it is desirable that the solidified layer be thick over the entire eroded surface of the furnace bottom refractory, but if it is too thick and the solidified layer is longer than the taphole level, it will damage the furnace bottom. The steel tends to become cold, which hinders the tapping operation. Even if it is not so abnormal, if the solidified layer grows locally in the center of the furnace bottom, the flow path for hot metal slag becomes smaller and the flow resistance increases, resulting in hot metal slag that can be discharged in one tap operation. The amount of melt decreases, and the melt tends to remain on the hearth, resulting in poor ventilation throughout the furnace and poor loading of the charge.

In order to achieve both stable tap slag work and effective protection of large objects at the bottom of the furnace, we have established a technology that can control the growth and development of the solidified layer at the bottom of the furnace, and established the optimal thickness and distribution of the solidified layer. It is therefore necessary to operate the blast furnace under optimal conditions.

In order to achieve this, not only the erosion condition of the heavy-duty material at the bottom of the furnace but also the online motoring of the solidified layer that repeatedly forms and disappears on the eroded surface must be +'+rN.

Since the 1-large-sized material at the bottom of the furnace gradually wears out after the blast furnace is fired, the side temperature values of the sensors at each part of the furnace bottom gradually increase to 1-) over a long period of time.
However, in the short term, depending on changes in blast furnace operating conditions and measures taken to protect the refractory, a solidified layer grows on the refractory and the side temperature value decreases. Therefore, the corrosion status of the refractory is estimated using the temperature measurement (di) at the time when the sensor of each part shows the maximum temperature value after burning, and the humidity measurement value is calculated at the time when the sensor temperature value decreases. It is necessary to successively estimate the distribution of the solidified layer extending IJt from the refractory erosion surface estimated at the previous point in time using the method.

The line of thickness distribution of the solidified layer that fades away, that is, the solidified layer line (
In order to estimate the erosion solidification layer line (hereinafter collectively referred to as the "eroded solidification layer line"), it is necessary to install multiple thermocouples or heat flow meters at the bottom of the blast furnace and perform heat transfer calculations at the bottom of the furnace.

Conventionally, the line of the eroded solidified layer at the bottom of the furnace has been estimated using a one-dimensional heat transfer calculation called I', using the actually measured temperatures detected by thermocouples at each part of the furnace bottom, or sometimes a two-dimensional heat transfer calculation. The element method has been adopted.

Estimation of the erosion solidified layer line at the corner of the furnace bottom is originally impossible by -dimensional heat transfer calculation, and even if the blast furnace hearth is simplified as an axisymmetric body with the longitudinal axis of the furnace as the axis of symmetry, Dimensional heat transfer calculations are essential.

The finite element method has generally been used for this two-dimensional heat transfer calculation, but this is a very time-consuming and tedious task.

In view of these circumstances, the inventors of the present invention
As shown in 84606, by applying a new numerical calculation method called the boundary element method, we are able to automatically estimate the erosion solidification layer line and online monitor the line, which could not be achieved with conventional technology, to protect the bottoms of multiple blast furnaces over the long term. By implementing countermeasures and thereby stabilizing operations, we were able to manage the reactor body by quickly responding to abnormalities such as the progress of erosion of large materials at the bottom of the reactor, and extend the life of the reactor.

Of course, the above-mentioned new method is based on the assumption that a number of temperature sensors equal to 1 are installed at each part of the bottom of the blast furnace, and that accurate temperature measurement data can be obtained.

However, in reality, the number of temperature sensors is small, and the number of sensors on one meridian section at the bottom of the furnace is, for example, about nine at most, as shown in FIG. In blast furnaces that were constructed a while ago, for example, as shown in FIG. 5, only one sensor is installed on the bottom of the furnace. In addition, the number of meridian cross sections of large furnace bottoms on which temperature sensors are installed is small, and there are only 4 at most.
It is about a cross section. This is because if many temperature sensors 3 are installed in many cross sections, the maintenance and management effort for the sensors and measurement value acquisition devices will be enormous, and in the end, they will be installed due to poor management. This was due to the fact that there were two kilometers of traffic that were not used.

[Problem that the invention seeks to solve]

In such a situation, there is a limit to the amount of accurate data that can be obtained, and even with the completely new method shown in Japanese Patent Application Laid-Open No. 60-184606, the accuracy of estimation and monitoring of the internal situation at the bottom of the blast furnace cannot be improved. There were limits.

By improving the side heating method, the uninvented method can be applied to the bottom of the furnace at the cross-sectional boundary (for example, 6 in Figs. 4 and 5) without increasing the number of sensors or temperature measurement data acquisition devices. The purpose is to provide a method that can easily measure continuous humidity distribution at any time, and the side temperature data obtained by this method is published in Japanese Patent Application Laid-Open No. 60-18460.
When combined with the method shown in Section 6, its true value will be demonstrated, and the accuracy of estimating the situation inside the reactor will be dramatically improved.

[Failure to solve the problem]

” - In order to achieve the above purpose, the inventor has proposed that, on any meridian section of the bottom of the blast furnace, the bottom surface of the furnace bottom has a line extending from the center of the bottom to the side wall skin or from the opposing side wall skin to the side wall skin. ,
In addition, a passage for a temperature sensor is built into the refractory on the side wall of the furnace bottom from just below the tuyere to the bottom plate of the furnace bottom, and both ends of the passage are open to the outside of the furnace, and a Δ11 temperature sensor is installed in this passage. We have developed a method to measure the continuous temperature distribution along the furnace meridian at the bottom of the furnace by inserting it in a movable manner and moving it arbitrarily.

[Effect]

1- When the method shown in the previous application is used to estimate the situation inside the reactor, it is mathematically reduced to a nonlinear optimization problem when combined with the present invention, so that the error between the measured temperature value and the calculated value is minimized. The eroded solidification layer line is determined.

Naturally, in this case, the more the number of temperature measurement points increases, and the more data from a wider range of positions can be obtained, the more accurate the estimation by this method becomes.

As described above, according to the present invention, it is possible to easily obtain a continuous temperature distribution at any time at the furnace bottom beam cross-sectional boundary 6k without increasing the number of temperature measurement sensors or temperature measurement data acquisition devices. As a result, the accuracy of estimating the situation inside the reactor can be dramatically improved. Furthermore, since the sensors can be replaced very easily and the number of sensors does not increase, the labor for maintaining and managing the sensors can be reduced, and the reliability of the measured values of all the sensors can be improved.

The apparatus used in the embodiments of the present invention has the following features: It is possible to continuously capture the temperature at any time at the boundary.

■ This increases the number of comparison points with calculated values and improves the accuracy of estimating the situation inside the reactor.

■ Sensors can be easily replaced when they deteriorate, and the number of sensors is small, making maintenance and management of sensors reliable.

It has the following advantages.

FIG. 1 schematically shows the structure of the bottom of a blast furnace having a stave cooling device 9 to which the method of the present invention is applied.

The hearth bottom is generally composed of various refractories 2 whose main components are carbon, silicon oxide, aluminum oxide, silicon carbide, etc., and in order to protect them, a cooling device is installed on the side wall of the hearth bottom and under the hearth bottom plate lO. 9 is provided.

Temperature measuring device: ξ11 is (
Between the refractory 2 and the cooling device 9, and the furnace bottom plate 10 Page 1;
It is embedded in a refractory 2 and consists of one or more temperature sensors 12, a winding device 13 for the sensors 12, and a passage 14 through which the sensors 12 are electrically connected. Further, if necessary, a device 15 (for example, a pulley) for guiding the temperature sensor 12 by changing its moving direction is provided. Temperature measuring device 11
is remotely and automatically operated, and the temperature of the side wall and bottom surface of the furnace bottom at any time can be collected as a continuous temperature distribution at each location. That is, the temperature sensor 12 is wound up or unwound by the winding device 13 and moves freely in the passage 14, and the sensor 12 captures the temperature of the contents of the passage [4], that is, the temperature of the refractories in each part, and At any meridian cross section of the bottom refractory 2, from the center of the hearth bottom to the side wall skin, or from the opposing side wall skin to the side wall skin, on the bottom side wall of the hearth there is one blade 8. It is possible to measure the continuous temperature surface distribution at any time from the bottom of the furnace to the bottom of the furnace. FIG. 2 is a schematic diagram illustrating an example;
As in the case in FIG. 1, it is possible to detect a continuous temperature distribution at the boundary of an arbitrary cross-section.

Details of the temperature sensor humidity sensing section 16 are shown in FIG.

Figure 3 shows a temperature sensor passage 14 with an inner diameter of 5 mm and an outer diameter of 10 mm.
A temperature sensing part 16 is installed in the middle of a temperature sensor 12 (-1 x 25 m) consisting of a JIS-specified sheath type thermocouple (outer diameter 3゜2 mm) using stainless steel piping with a diameter of 1 mm. Here is an example of inserting . The pipe 14 is embedded in the refractory 2.

The temperature sensor 12 is wound up by winding devices 13 at both ends.
The winding is performed, and the temperature sensing part 16 can freely slide left and right inside the pipe 14 to detect the temperature of each part.

By installing temperature sensor passages on the bottom side wall and the bottom of the furnace bottom of an arbitrary meridian cross section and measuring the temperature using the method of the present invention, the accuracy of estimating the erosion solidified layer line of the cross section can be greatly improved. It does not bring about immeasurable effects on stabilizing blast furnace operations such as protecting the refractories 2, thereby extending the life of the furnace 1, and ensuring proper tapping slag work.

〔Example〕

FIG. 6 shows the temperature measurement results of the bottom of a large blast furnace of 50,001-ton grade pig iron manufactured by the method of the present invention.

FIG. 6 shows the temperature measurement result 17.18 on a certain day about 7 years and 4 months after firing in the enlarged blast furnace and the estimated erosion line J9.20 of the refractory 2 based on the temperature measurement result.

Measurement results 17 using the method of the present invention in the radial direction and height direction of the furnace bottom and measurement results 1 using a conventional fixed temperature sensor
8 and 8. As shown in FIG. 6, they agree within a range of ±5° C., and the temperature of each part is correctly measured within the error range of the sensor itself.

The effectiveness of the method of the present invention, which is different from the conventional method, is that, as shown in Figure 6, by capturing the continuous temperature distribution along the temperature sensor path, it is possible to accurately grasp the local temperature outside. be. The erosion lines estimated from the two measurement results 17 and 18 were profiles 19 and 20 shown in FIG.

As can be seen from FIG. 6, the erosion line 19 obtained from the measurement result 17 obtained by the method of the present invention indicates that there is localized abnormal erosion immediately below the side wall tap hole level 5. Such localized abnormal erosion can cause major accidents such as damage to the bottom of the furnace, and even if an accident does not result, measures to protect the affected area will significantly reduce production and increase production costs. Therefore, early detection of abnormal local erosion and early implementation of countermeasures are essential for stable operation and extension of blast furnace life.

As is clear from Fig. 6, with the conventional method, it is not possible to detect local temperature rises and, by extension, to accurately predict localized abnormal erosion of the refractory 2, which has a high possibility of causing a major accident. In the conventional method, it is possible to grasp the local temperature rise only by burying an extremely large number of temperature sensors 3 in the bottom of the furnace, but this is impossible due to the cost and maintenance of the sensors and data acquisition equipment. .

According to the method of the present invention, two local temperature rises can be captured with at least two sensors in each meridian cross section, and therefore,
The erosion line of the hearth bottom refractory 2 can be accurately grasped, and its usefulness is immeasurable. Furthermore, the method of the present invention can be used to estimate the distribution of the solidified layer that repeatedly grows and disappears inside the hearth bottom, making it possible to realize more accurate hearth bottom management and, by extension, stable operation.

〔Effect of the invention〕

The method of the present invention makes it possible to continuously understand the temperature distribution at the bottom of the blast furnace, and by applying this to the estimation method of the erosion solidified layer line using the boundary element method, the erosion of large resistant materials at the bottom of the furnace can be confirmed. Precise and accurate estimation of progress greatly contributes to N, furnace body management, and extension of furnace life.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of the bottom of a blast furnace according to the method of the present invention, FIG. 1 schematically shows the installation position of a temperature measurement passage in a blast furnace equipped with a stave cooling device, and FIG. The following is an outline of the installation location of the temperature measurement passage in a blast furnace equipped with a water cooling bag. Third
The figure is an explanatory diagram showing details of the sensor temperature sensing part used in the temperature measuring method of the present invention, Figures 4 and 5 are explanatory diagrams showing an example of installation of a conventional temperature measuring sensor with a meridian cross section, and Figure 6 is , is an explanatory diagram showing a comparison of temperature measurement results by the temperature measurement method of the present invention and a conventional temperature measurement sensor, and a comparison of estimation results of a refractory corrosion line based on the respective temperature measurement results. 1... Axis of symmetry 2... Hearth bottom resistant material 3... Conventional temperature sensor 4... Refractory erosion line 5... Taphole level 6... Meridian section boundary line 7...・During construction, hearth bottom heavy-duty 8...blade 1 lebel 9...cooling device io...heart bottom plate 11...temperature measuring device 12...side temperature sensor 13...A11l temperature sensor winding Device 14...Temperature sensor passage 15...Device 16 for changing the movement/induction direction of the temperature sensor 16
...Temperature sensing part 17 of temperature sensor...71+11 constant results (continuous temperature distribution) by the method of the present invention 18...Measurement results by conventional side temperature sensor 19...
Unreleased I! Estimated erosion line 20 based on measurement results by + method... Estimated erosion line 21 based on measurement results by conventional temperature sensor... Blast furnace outer wall iron skin

Claims (1)

[Scope of Claims] 1. A passage for a temperature sensor along the meridian section of the blast furnace is housed in the refractory at the bottom of the blast furnace, with both ends of the passage open to the outside of the furnace, and the temperature sensor is movable within the passage. 1. A method for measuring temperature at the bottom of a blast furnace, comprising: inserting the passage through the passage, and moving a temperature sensor inside the passage from both ends of the passage to measure a continuous temperature distribution along the furnace meridian at the bottom of the furnace.