JP3188307B2 - Monitoring method of hot stove - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring a hot stove, which is a part of a steel making facility, based on temperature.

[0002]

2. Description of the Related Art A hot blast stove is a facility for heating air sent into a blast furnace (pig iron making facility, blast furnace), in which gas combustion and blowing with high-pressure air are alternately repeated. For this reason, the inner wall of the hot blast stove is covered with heat-resistant bricks, and the outer side is covered with an outer wall made of iron (called an iron shell). Here, in particular, since the iron shell is an important structural member that covers the entire hot blast stove, it is designed to have sufficient strength to withstand high temperature and high pressure.

However, if a part of the heat-resistant brick on the inner wall is broken or dropped due to thermal fatigue during operation of the hot blast stove, the steel in this region is exposed to the high temperature air in the furnace. In this case, there is a risk that the corresponding portion of the steel shell glows red, in the worst case, cracks occur, or hot air in the furnace blows out. In order to avoid such an abnormal situation, a thermometer has conventionally been mounted on the surface of the steel shell and monitored by a method of predicting this kind of abnormality from a change in the temperature (Japanese Utility Model Application Laid-Open No. 29248/1985). . That is, a temperature sensor such as a thermocouple is attached to an appropriate position on the surface of the steel shell so that a temperature rise due to the generation of red heat can be detected at an early stage.

[0004]

The conventional method for monitoring a hot stove using a thermocouple as described above has a disadvantage that the position where the thermocouple is attached can be measured only at "points". If this method is used to monitor the entire surface of the skin constituting the outer wall of the hot stove with a thermocouple, thousands of thermocouples must be spread around the outer wall, which leads to cost and workability problems. Could not be put to practical use at all.

[0005] For this reason, in the conventional monitoring method, only a few to at most several tens of thermocouples are arranged at important points of the steel shell, and their temperatures are monitored. However, with this number of measurement points, it is far from the overall monitoring of the hot stove, and even if it is limited to monitoring the welding line where the possibility of cracking is relatively high, it is not possible to cover the entire area,
The monitoring method was inadequate.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a method for monitoring a hot stove capable of constantly monitoring the entire steel shell.

[0007]

In order to achieve the above object, a method for monitoring a hot stove according to the present invention comprises the steps of:
Weld the guide pipe along the steel welding line and insert it inside
Laying optical fiber by inserting the fiber SUS tubed, from the time of the backward Raman scattered light intensity of the pulse light input to the optical fiber and to its return to measure the temperature distribution in the laying region of the optical fiber Together with the temperature of the measurement site
Monitor the distribution on a display and further measure
If the temperature of the part exceeds the specified upper limit temperature, an alarm
Generate and generate the corresponding hot-blast stove surface
The temperature is displayed on the display screen so as to monitor the temperature distribution of the entire area of the steel shell of the hot stove so that the abnormality can be detected.

[0008] In addition, the measurement of the temperature distribution on the surface of the iron shell is fragile.
It is performed along the steel welding line, which is a part, which is preferable for abnormality monitoring.

[0009] The optical fiber is laid along the welding line over almost the entire surface of the steel shell surface of the hot blast stove. This optical fiber may be continuously laid in a spiral form with one fiber, or a plurality of fibers may be dispersed and installed so that each fiber can be selectively switched by an optical switch. A pulse is incident from the input end of the optical fiber, and the backward Raman scattered light is detected.

The temperature is detected from the intensity of the Raman scattered light (the intensity ratio between the Stokes light and the anti-Stokes light), and the measurement position (or section) is detected from the time interval from the incidence to the return, and the surface of the iron skin is detected. Is measured. The obtained temperature distribution on the steel surface is graphically displayed on a CRT screen so that the temperature pattern and the actual temperature can be easily visually recognized in terms of density and color.

It is possible to monitor the temperature distribution along the steel welding line, which is a fragile portion, to detect abnormal temperature rise at an early stage, and to cope with troubles caused by red heat, cracks, and the like. it can.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. First, the configuration of the optical fiber thermometer used in the method of the present invention will be described. As shown in FIG. 7, the optical fiber thermometer 100 has a measuring unit 3 similar to the conventional device.
A pulse drive circuit 4 as a light pulse oscillating means and a pulse semiconductor laser (hereinafter, referred to as an LD) 5 are provided therein, and light pulses enter the optical fiber 2 from the LD 5 via a light splitter 6. An optical switch 14 serving as selection switching means is interposed at the base end of the optical fiber 2 in the measuring section 3.
It is driven in synchronization with D5.

The optical switch 14 has a half (0.5 m) of an optical pulse width (1 m in this embodiment, corresponding to the distance resolution).
m) A pair of length adjusting optical fibers 1 having different lengths
5 and 16 are built in. And the optical switch 14
Is driven, one of the fiber length adjusting optical fibers 15 and 16 is instantaneously connected to the optical fiber 2. Therefore, in the apparatus of the present embodiment, two types of optical fibers 2 (that is, detection paths) having different lengths by 0.5 m are provided. Of the two types of optical fibers 2, the shorter detection path is defined as a first route,
The longer detection path is defined as a second route.

On the other hand, the optical fiber 2
A thermostat 17 for storing the optical fiber 2 is provided.
Is kept constant within a predetermined section (1 m in this embodiment). The optical fiber 2 coming out of the thermostat 17 is laid along the DUT 1 as in the conventional apparatus. In the measuring section 3, two types of interference filters 7, 8 built in the optical demultiplexer 6, and first and second avalanche photodiodes (hereinafter, referred to as APDs) are provided.
In addition to the components 9 and 10, a high-speed averaging device 11 is provided.

An optical fiber 2 is laid along an object to be measured (power equipment, plant, etc., in this case, iron skin) 1, and a pulsed semiconductor laser driven by a pulse drive circuit 4 in a measuring section 3 on the optical fiber 2 From 5, light pulses are incident. Next, the Stokes light and the anti-Stokes light, which are two components of the Raman backscattered light, of the backscattered light at each part of the optical fiber 2 are separated by two kinds of interference filters 7 and 8 in the optical demultiplexer 6. And the first and second
APD (avalanche photo diode) 9,10
Performs photoelectric conversion. Next, the high-speed averaging device 11
Within, after A / D conversion of the intensity of these two components,
The data is added and stored in the memory corresponding to each delay time. Then, after all the backscattered light from the optical fiber 2 returns, an optical pulse is again incident on the optical fiber 2 to detect Raman backscattered light.

After repeating these operations many times (for example, several thousand times), averaging is performed by dividing by the number of repetitions. This averaging process is performed for the purpose of preventing a measurement error due to extremely weak Raman backscattered light. Thereafter, based on the intensity ratio between the Stokes light and the anti-Stokes light at each part output from the measurement unit 3, the temperature distribution information is obtained by the data processing device 12 and displayed on the screen of the display 13. In addition, Stokes light and anti-
To obtain the temperature from the intensity ratio with the Stokes light, a map created in advance based on experiments, calculations, and the like is used.

A data processing device 12 as a calculating means and a display 13 are arranged outside the measuring section 3.
It should be noted that the data processing device 12 is different from the above-described conventional device in that the phase is determined based on the intensity ratio between the Stokes light and the anti-Stokes light at each part of the first route and the second route output from the measurement unit 3. It has a function of calculating two temperature distribution measurement values shifted from each other and calculating a temperature distribution measurement value in a section where the pulse width is divided into two based on these.

In the present invention, the optical fiber 2 connected to the optical fiber thermometer 100 is laid on the surface of the steel shell 1 of a hot stove, and the temperature distribution is measured. First, a guide pipe G is welded to the surface of a steel shell, and a fiber containing a SUS tube is inserted and laid therein (step S1 in FIG. 1). This guide pipe G is shown in FIG.
As shown in the figure, the wire is wound at regular intervals so that the temperature can be monitored over the entire surface of the steel skin. The guide pipe G
In particular, the welding line, which is a fragile portion and has a high possibility of cracking, is laid so as to cover all of the welding line. In this case, one long optical fiber may be inserted through all the guide pipes, or a plurality of optical fibers may be dispersed and wound so that the measurement route of each optical fiber can be selectively switched by an optical switch. You may.

However, since the measurable length of an optical fiber is limited by the characteristics of the material constituting the fiber, it is generally not preferable to measure 2 km or more with one fiber. Also, the shorter the fiber, the easier the work is. For this reason, when a wide range of monitoring is required, such as in a hot stove, a method of covering with a large number of switchable optical fibers is desirable. This embodiment also employs this method, and is capable of periodically switching 20 optical fibers via switching means A and B. The optical fiber 2 is of course made of a fiber of a material that can be used even in a high temperature range of about 300 ° C.

The laser pulse light is made incident from one end of the optical fiber 2 arranged as described above, and the backward Raman scattered light is detected by the measuring section 3 of the optical fiber thermometer 100 (FIG. 1, step S2). In measuring the temperature distribution in the present embodiment, first, the LD 5 and the optical switch 14 are driven by the pulse driving circuit 4 and the optical pulse is transmitted to the optical fiber 2 (from among the many switching means A, B), and simultaneously switches the detection path between the first route and the second route.

For example, when an optical pulse is first incident on the first route, scattering occurs at each part of the optical fiber 2, and
The backward scattered light returns to the incident end of the optical fiber 2.
Of the returned backscattered light, Stokes light and anti-Stokes light, which are two components of Raman backscattered light, are separated by two types of interference filters 7 and 8 in an optical demultiplexer 6.
Each is photoelectrically converted by the first and second APDs 9 and 10. Next, in the high-speed averaging device 11,
After the A / D conversion of the intensities of these two components, they are added and stored in a memory corresponding to each delay time. Next, after all the backscattered light from the first route returns, an optical pulse is incident on the second route, and the intensity of the two components is stored in the memory of the high-speed averaging device 11 in the same procedure. Then, after the above operation is repeated many times, an averaging process is performed on each of the first route and the second route by dividing by the number of repetitions.

Thereafter, the phase (distance corresponding to the delay time) is shifted by 0.5 m in the data processing device 12 based on the intensity ratio between the Stokes light and the anti-Stokes light at each part output from the measuring unit 3. By obtaining two temperature distribution measurement values (FIGS. 8 and 9) and comparing them, the temperature measurement point can be determined with high accuracy. The measurement start point in FIG.
7 (point P in FIG. 1). At this time, the measurement start point is specified by the speed of the light pulse in the optical fiber 2 and the LD5.
The calculation is performed by calculating the delay time of the backscattered light from the distance from the temperature to the constant temperature bath 17 and the like. Further, the symbol (T
₁₁ , T ₁₂ , T ₁₃ , ─) indicate the section average temperature for every 1 m in the first route, and the symbols (T ₂₁ , T ₂₂ , T ₂₃ ,
─) shows the section average temperature for every 1 m in the second route. The symbols (t1, t2, t) in FIGS.
3─) shows the section average temperature every 0.5 m, but it has not been obtained yet at this time.

Next, the data processing device 12
The section average temperature for each 0.5 m is calculated based on the temperature distribution measurement value for each 1 m. First, the data processing device 12 obtains the first section average temperatures t1 and t2. However, in the section between 0 and 1 m in the first route, the temperature is constant because the optical fiber 2 is in the thermostat 17 as described above. It is kept in. Therefore, of course, the section average temperature t1,
t2 are both equal to interval average temperature T _11, t1 = t2
= The T _11.

Next, the data processing device 12 obtains the section average temperature t3.
interval average of m intervals temperature T ₂₁ is the section average temperature t2, t3
Because it is the average value, and _{T 21 = (t2 + t3)} / 2 becomes, t3 = 2T ₂₁ -t2. Here, as described above, because it is t2 = T _11, determined as t3 = 2T ₂₁ -T _11. In the same procedure, the average temperature in the section after t4 is also gradually obtained, and then the data processing device 12 puts this into temperature distribution information and displays it on the display 13 on the screen.

After measuring the temperature of each measurement point of one optical fiber 2 in this way, the switching means A and B switch the channel to the next optical fiber, and determine the position and temperature in the same manner. A temperature pattern for the entire steel skin can be created. The temperature distribution on the surface of the iron shell thus obtained is measured every 1 m (step S3), and the result is displayed on the display device 13 via the data processing device 12 (step S4). This display is graphically displayed as an illustration for easy understanding by the operator. In other words, as shown in the display example of FIG. 4, the surface of the iron skin of the hot stove is divided and displayed in a mosaic shape (decomposition power = 1 m), and the temperature of each mosaic region is displayed according to the concentration, so that the temperature pattern can be seen at first You can understand. The temperature display is, for example, 380 ° C., 360 ° C., 34
The concentration is classified at a pitch of 20 ° C., for example, 0 ° C.... 100 ° C. or less (FIG. 5). Further, the temperature history of each measurement point is stored for a long period of time, and the change can be viewed in the form of a trend graph.

Further, the display display of each part of the hot stove viewed from the north, south, east and west can be selected on the screen. For example, if any of the selection fields in FIG. 5 is designated by a cursor, a screen viewed from a desired observation direction in FIG. 4 can be obtained. If the temperature of the measurement site exceeds a predetermined upper limit temperature, an alarm is generated and the corresponding steel surface of the hot stove 101 is dis- played.
The information is displayed on the screen of the play 13 so that the abnormality diagnosis can be performed early and reliably (step S5).

In this embodiment, one hot blast stove (H
Although S) is a measurement target, an optical fiber may be wound around a plurality of hot blast stoves and may be centrally managed by one thermometer 100 (FIG. 6). As described above, according to the method of the present embodiment, thousands of measurement points can be monitored by one optical fiber thermometer. In addition, the use of the two optical fibers 15 and 16 for adjusting the fiber length and the thermostatic bath 17 makes it possible to obtain a spatial resolution twice that of the conventional apparatus. In addition, since the measurement results are displayed on an easy-to-understand display, a monitoring system suitable for safety management can be constructed.

As described above, the method for monitoring a hot blast stove according to the present invention employs a guide pie along a steel welding line on the surface of the hot blast stove.
SUS tube inside the tube
Insert the laying optical fiber, from the time of the backward Raman scattered light intensity of the pulse light input to the optical fiber and to its return to measure the temperature distribution in the laying region of the optical fiber
At the same time, monitor the temperature distribution of the measurement site on the display
The temperature along the welded seam, which is the fragile part, is displayed.
Monitor the distribution constantly to detect abnormal temperature rises early and
Troubles caused by cracks, etc.
Can be dealt with. Further, the temperature of the measurement site is
If an alarm occurs when the temperature exceeds the specified upper limit
Display the corresponding surface area of the hot-blast stove
Is displayed on the screen, so that abnormality diagnosis can be performed quickly and reliably.
be able to. From the above, it is possible to reliably monitor the entire shell of the hot blast stove. In addition, since the measurement results are displayed on the monitor in an easy-to-read format, it is extremely reliable as an abnormality monitoring system, and is excellent in improving the safety of hot stove equipment and related equipment, and improving the operation rate of steelmaking equipment. It has the effect.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating the method of the present invention.

FIG. 2 is a sectional view showing the inside of a hot blast stove.

FIG. 3 is a schematic diagram showing an optical fiber laid state on a surface of a steel shell.

FIG. 4 is a display example of a temperature distribution measurement result on a display screen.

FIG. 5 is a screen showing a temperature width and an observation direction on a display screen.

FIG. 6 is a principle configuration diagram of a temperature monitoring system using an optical fiber.

FIG. 7 is a configuration diagram of an optical fiber thermometer.

FIG. 8 is a temperature measurement example of a first route.

FIG. 9 is a temperature measurement example of a second route.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DUT (iron) 2 Optical fiber 3 Measuring part 4 Pulse drive circuit 5 Pulse semiconductor laser 12 Data processor 13 Display 100 Optical fiber thermometer 101 Hot stove A, B Switching means R Heat-resistant brick G Guide pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01K 11/12

Claims (1)

(57) [Claims] 1. Along a welding line on a surface of a shell of a hot blast stove.
Weld the guide pipe and put SUS tube inside
Laying optical fiber by inserting the fiber, from the time of the backward Raman scattered light intensity of the pulse light input to the optical fiber and to its back, while measuring the temperature distribution in the laying region of the optical fiber, measured Displays the temperature distribution of the part
On the monitor, and furthermore, the temperature of the measurement site is predetermined.
If the temperature exceeds the upper limit, an alarm is generated and
The corresponding hot-blast stove surface area is displayed on the screen of the display.
A method for monitoring a hot blast stove, wherein the method is displayed on the display .