JP4056534B2 - Furnace bottom temperature measuring method and apparatus, and melting furnace bottom monitoring method and apparatus - Google Patents

Description

  The present invention relates to a furnace bottom temperature measuring method and apparatus for measuring the temperature distribution of the furnace bottom surface of a melting furnace over a wide range and with high accuracy, and further, an abnormality in the furnace bottom of the melting furnace based on the measured temperature. The present invention relates to a method and apparatus for monitoring the bottom of a melting furnace.

The need for melting furnaces for melting waste is increasing from the viewpoint of detoxification, volume reduction, and resource recycling of waste. Known melting furnaces include a burner type melting furnace for melting an object to be processed using heavy oil or the like as a fuel, an electric resistance type melting furnace and a plasma type melting furnace for melting an object to be processed using electricity as a heat source.
As an example, a plasma melting furnace will be described with reference to FIG. 7. This plasma melting furnace 50 includes a main electrode 51 suspended from the top of the furnace and a furnace bottom electrode 52 disposed on the furnace bottom. A plasma arc is generated by applying a DC voltage 53 between these two electrodes. And the to-be-processed object dropped in the furnace main body 54 from the charging hopper 55 is heated and melted by plasma heat. The object to be processed is melted and molten slag 56 and molten metal 57 having a specific gravity larger than that are accumulated in the furnace main body 54 and discharged from the outlet 58. Moreover, since the inside of the furnace main body 54 is maintained at a high temperature, the inside thereof is formed of a refractory material such as an irregular refractory material 60 or a refractory brick 61, and a structure in which the refractory material is covered with an iron shell 62 is employed. .

  In such a melting furnace, there is a possibility that molten metal or molten slag leaks from the inside of the furnace, and there is a risk of a steam explosion or the like, so the furnace bottom is often not cooled with water. However, in the case of natural air cooling, the cooling is weak and the refractory is eroded by metal or slag. In general, the progress of erosion occurs from the joint where the refractories adhere to each other. When the erosion of the joint progresses, the fixing of the refractory brick becomes poor, and the refractory brick having a specific gravity smaller than that of the metal peels off and floats in the metal. The refractory brick gradually expands around the peeling portion, and the temperature of the iron skin near the peeling portion increases. If the iron skin is heated to a temperature higher than the heat-resistant temperature (about 350 ° C.), there is a risk that defects such as deformation and dropout may occur. Therefore, it is necessary to monitor the furnace skin temperature at the bottom of the furnace.

  Conventionally, as described in Patent Document 1 (Japanese Patent Laid-Open No. 11-218320) or the like, the thermocouple 65 (see FIG. 7) is used to measure the furnace temperature as it penetrates the refractory from the bottom of the furnace body. It was common to install and measure the temperature of the refractory, or to measure the temperature of the furnace bottom surface by installing a thermocouple on the furnace bottom iron skin.

JP 11-218320 A

However, the method described in Patent Document 1 can only measure the furnace bottom temperature locally. However, it is unclear which refractory material will float out of the refractory material laid almost on the bottom of the furnace, so it is necessary to grasp the temperature distribution over a wide range of the furnace bottom surface. In this case, in Patent Document 1, it is necessary to install a large number of thermocouples, and the temperature distribution obtained by combining the local temperatures obtained by a plurality of thermocouples does not go beyond the range of estimation, and the accuracy is high. It was not a good measurement.
Accordingly, in view of the above-described problems of the prior art, an object of the present invention is to provide a furnace bottom temperature measuring method and apparatus capable of accurately measuring the temperature of the furnace bottom surface over a wide range. Furthermore, it aims at providing the bottom monitoring method and apparatus of a melting furnace which can detect abnormality of a bottom using the said bottom temperature measuring technique.

Therefore, in order to solve this problem, the present invention provides:
A thermography device is installed at a position including the furnace bottom surface of the melting furnace in the measurement range, and a black body with an emissivity set to a value of 1.0 is provided in the vicinity of an arbitrary temperature measurement point included in the measurement range. Every
Setting the reference emissivity to a value of 1.0 in advance, and measuring the black body temperature from the radiant energy of the black body with the thermography device;
A step of obtaining an emissivity at which a measurement point temperature measured from the radiant energy of the measurement point by the thermography device matches the black body temperature;
Setting the obtained emissivity to the emissivity of the measurement range, and measuring the temperature distribution of the measurement range by the thermography device,
The black body is provided on the surface of a furnace bottom corresponding to a line connecting a melting furnace outlet from a center position of the melting furnace .

As in the present invention, by measuring the radiant energy from the bottom of the furnace using a thermography apparatus, a wide temperature distribution in the bottom of the furnace can be measured. Here, the thermography device is known as a thermometer that can measure the temperature of the measurement object by capturing radiant energy from the measurement object in a non-contact manner, but the emissivity of the measurement object is the type, It is known to be subject to various factors such as shape and temperature. Therefore, in order to perform temperature measurement with higher accuracy, it is necessary to accurately grasp the emissivity of the measurement area at the bottom of the furnace. Therefore, as in the present invention, the emissivity is 1. An ideal black body with a value of 0 is provided on the bottom of the furnace, and the emissivity in the measurement area is obtained based on the temperature of the black body and the temperature in the vicinity of the black body, enabling accurate temperature measurement. It becomes.

Further, as in the present invention , a black body is provided at any position in the flow direction of the molten slag and on the line connecting the tap port from the approximate center position of the melting furnace, and is likely to become the highest temperature in the melting furnace. By setting the vicinity of the spout where the refractory material in the furnace is significantly eroded as the measurement range, it is possible to reliably detect an abnormality in the furnace bottom.

In the present invention, a thermography apparatus is installed at a position including the furnace bottom surface of the melting furnace in the measurement range, and the emissivity is set to a value of 1.0 in the vicinity of an arbitrary temperature measurement point included in the measurement range. Providing a plurality of black bodies, setting a reference emissivity to a value of 1.0 in advance, and measuring the black body temperature from the radiant energy of the plurality of black bodies with the thermography device;
A step of obtaining an emissivity at which a measurement point temperature measured from the radiant energy of the measurement point by the thermography device matches the black body temperature;
Setting the obtained emissivity to the emissivity of the measurement range, and measuring the temperature distribution of the measurement range by the thermography device,
A plurality of the black bodies are provided on a concentric circle with the center position of the melting furnace as a central axis, or a plurality of black bodies are provided in the radial direction of the melting furnace, and the temperature distribution of the furnace bottom surface corresponding to the plurality of black bodies is determined. It is characterized by being measured.
This is because the temperature change on the concentric circle of the melting furnace is small due to the relationship between the temperature of the molten slag and the molten metal. By providing multiple black bodies in the concentric circle, errors in emissivity due to the temperature change can be minimized. It is possible to more accurately measure the temperature distribution in the measurement area. Further, since the temperature distribution in the radial direction is relatively large, the temperature dependence of the emissivity can be corrected by providing a plurality of black bodies here.
In addition, it is preferable that the selected wavelength of the thermography device is in the range of 8 to 14 μm, thereby preventing the influence of sunlight on the radiant energy detected by the thermography device, and enabling more accurate temperature measurement. It becomes.

Furthermore, in the bottom monitoring method of the melting furnace using the previous bottom temperature measurement method,
The method includes a step of detecting a high temperature region showing a higher temperature than that during normal operation based on the measured temperature distribution, and a step of detecting an abnormality of the furnace bottom based on the detected high temperature region.
Furthermore, the step of determining whether the high temperature region detected in the high temperature region detection step is local or wide area,
When it is determined that the high-temperature region is wide-area, determining whether the furnace temperature of the melting furnace is higher than the appropriate temperature based on other measurement factors;
A step of determining that an abnormality has occurred in the refractory material at the bottom of the furnace when the temperature in the furnace is appropriate or when the high temperature region is local.
In this way, by detecting the high temperature region from the measured temperature distribution, it is possible to accurately grasp problems such as erosion of the refractory material at the bottom of the furnace and floating even during operation. It is possible to prevent deformation, dropout, and the like. The other measurement factors include, for example, a molten slag temperature measured with a thermocouple or a radiation thermometer, a refractory material temperature measured with a thermocouple, a heat quantity of cooling water on the furnace wall, and the like.

Further, as an invention of the apparatus, a thermography apparatus installed at a position including the furnace bottom surface of the melting furnace in the measurement range, and an emissivity provided in the vicinity of an arbitrary temperature measurement point included in the measurement range is 1.0. And a black body set to the value of
Storage means for storing a black body temperature measured by the thermography apparatus with a reference emissivity set to a value of 1.0, and radiation whose measurement point temperature measured by the thermography apparatus matches the black body temperature An emissivity correction means for determining a rate, and a control device,
Set the emissivity obtained by the control device to the emissivity of the measurement range, measure the temperature distribution of the measurement range by the thermography device,
The black body is provided on the surface of a furnace bottom corresponding to a line connecting a melting furnace outlet from a center position of the melting furnace .

Also, characterized in that arranged at a position off the right under the thermography of the furnace bottom, which makes it possible to prevent damage to the thermographic apparatus due to dropping such as melt from the melting furnace.
Further, in the case of providing a plurality of the black bodies, a plurality of the black bodies are provided on a concentric circle with the center position of the melting furnace as a central axis, or a plurality of black bodies are provided in the radial direction of the melting furnace. .
Furthermore, it is preferable that the selected wavelength of the thermographic apparatus is in the range of 8 to 14 μm.
In the bottom monitoring device of the melting furnace using the bottom temperature measuring device,
The control device comprises means for detecting a high temperature region showing a higher temperature than during normal operation based on the measured temperature distribution, and means for detecting an abnormality in the furnace bottom based on the detected high temperature region. Features.

  As described above, according to the present invention, a wide temperature distribution in the furnace bottom can be easily measured, and an accurate emissivity is calculated by providing a black body, and temperature is measured based on this. Therefore, it is possible to measure the temperature at the bottom of the furnace with high accuracy, and as a result, it is possible to detect problems such as erosion of the furnace bottom refractory material and floating of the refractory material at an early stage, and to prevent defects such as deformation and dropout of the iron skin on the furnace bottom surface. It can be prevented in advance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
In this embodiment, a plasma melting furnace will be described as an example of a melting furnace to be measured and monitored at the furnace bottom. However, the present invention is not particularly limited as long as it is a melting furnace for melting an object to be processed.
FIG. 1 is an overall configuration diagram showing a side cross section of a melting furnace provided with a furnace bottom monitoring device according to an embodiment of the present invention, and FIG. 2 is a side showing an outline of a furnace bottom portion provided with a furnace bottom monitoring device according to this embodiment. FIG. 3 is a cross-sectional view, and FIG. 3 is a plan view showing an outline of a furnace bottom portion provided with the furnace bottom monitoring device shown in FIG.

  First, a plasma melting furnace in which a furnace bottom temperature measuring device and a monitoring device according to this embodiment are installed will be described with reference to FIG. In the plasma melting furnace 1, the main electrode 11 is suspended from the furnace lid of the furnace body 14, and the furnace bottom electrode 12 is inserted from the furnace bottom 17 to face the main electrode 11. In the plasma ash melting furnace 10, a direct current is passed between these electrodes by a direct current power source 13 to generate a plasma arc 24 in the furnace. An object to be processed input from the input hopper 21 is dropped into the furnace from an object input port 20 provided on the furnace wall, melted by plasma arc heat and Joule heat of current flowing between the electrodes, and melted. The slag 22 accumulates at the furnace bottom. In addition, a molten metal 23 is formed in the lower portion of the molten slag 22 due to a difference in specific gravity. After melting, it is discharged from the tap 25 as appropriate.

The inner side of the side wall and the lid of the furnace body 14 is formed of an irregular refractory material 15, and a refractory brick 18 is lined on the bottom, and the outer surface thereof is covered with an iron skin 16.
The plasma melting furnace 10 is provided with various measuring instruments (not shown) in order to perform a smooth and proper operation, and the operation and in-furnace monitoring are performed based on the measured values obtained thereby. For example, a slag thermometer installed in the measurement opening provided in the furnace lid, a thermocouple embedded in the furnace wall to detect the temperature of the refractory brick, the inlet temperature and outlet of the cooling water flowing through the outlet Examples include a temperature detector for detecting temperature, a temperature detector for detecting the temperature in the furnace, an ammeter and a voltmeter for measuring the current and voltage between the electrodes, and a meter for measuring the ash charged into the furnace.

In the present embodiment, a temperature measuring device for measuring the temperature of the furnace bottom 17 is provided. This temperature measurement device includes a thermography device 30 and a control device 40 having an image processing function.
The thermography device 30 is a well-known device that detects the amount of radiant energy emitted from a measurement object in a non-contact manner and determines the temperature of the measurement object from the amount of radiant energy. The thermography apparatus 30 is installed at a position including at least a part of the iron skin surface of the furnace bottom 17 in the measurement range, and particularly preferably, the furnace bottom 17 is moved from a lateral position outside the melting furnace 10. Installed at the position to be measured. Thereby, when molten slag 22 grade | etc., Flows out, it is prevented from falling to the thermography apparatus 30 and being damaged. A plurality of thermography devices 30 may be provided. Further, when the thermographic device 30 is disposed immediately below the furnace bottom, the thermographic device 30 may be freely movable by a jig or the like. Further, the thermographic device 30 may be configured to be movable, and may be periodically moved to a position having a different measurement range.
The selected wavelength of the thermographic device 30 is preferably 8 to 14 μm. As a result, accurate measurement is possible without being affected by sunlight.

Further, in the thermography device 30, since a large error occurs when the emissivity of the measurement object changes, in order to eliminate this, a correction mechanism for correcting the emissivity is provided in this embodiment. As shown in FIGS. 2 and 3, an emissivity 1.0 or a black body 31 approximated to this is provided in the vicinity of the temperature measurement point 32 included in the measurement range 33 in the furnace bottom 17. The black body 31 may be coated with a black paint, or may be processed and treated in the same manner, and its form is not particularly limited.
One or a plurality of the black bodies 31 are provided. Further, it is preferable that the black body 31 is installed at a position corresponding to the line connecting the furnace bottom electrode 12 and the tap outlet 25 along the slag flow direction in the furnace bottom 17. This is because the measurement range 33 is the vicinity of the spout where the melting furnace 10 is likely to reach the highest temperature and the refractory material in the furnace is significantly eroded.
Further, when a plurality of the black bodies 31 are provided, they are preferably provided concentrically around the electrode 12. This is because the temperature change is small on the concentric circle of the melting furnace 10, and by providing a plurality of black bodies 31 concentrically, errors in emissivity due to the temperature change are minimized, and the temperature distribution in the measurement range 33 is further improved. This is for more accurate measurement. Further, a plurality of them may be provided in the radial direction of the furnace bottom 17, and since the temperature distribution is relatively large in the radial direction, the temperature dependence of the emissivity can be compensated by providing a plurality of black bodies here. .

With the configuration described above, by correcting the reference emissivity epsilon _b set in advance, the furnace bottom steel shell surface is a measurement range 33 per method of calculating the specific emissivity will be described with reference to FIGS.
As shown in the figure, first, the reference emissivity is set to ε _b equal to 1.0 or a value approximate thereto, and the temperature T _b of the black body 31 is measured by the thermography device 30 (S1). The black body temperature _Tb thus recorded is recorded (S2). Further, the thermographic apparatus 30 is set to an arbitrary predicted emissivity ε _t , the measurement point temperature T _t is measured from the radiant energy of the measurement point 32, and the predicted emissivity ε _b is changed stepwise. (S3) The predicted emissivity ε _t when the black body temperature T _b substantially coincides with the measurement point temperature T _t is set to the emissivity of the measurement range 33 (S4).
In this way, the emissivity ε _t of the furnace bottom iron skin surface is set, and the temperature distribution of the furnace bottom 17 is measured by the thermography device 30 according to the emissivity. This makes it possible to obtain an accurate furnace bottom temperature distribution.

Furthermore, in this embodiment, there is provided a device for monitoring the furnace bottom based on the furnace bottom temperature measured as described above.
The furnace bottom monitoring device includes a thermography device 30 and a control device 40 connected to the thermography device 30, and a control signal calculated by the control device 40 is transmitted to various control devices of the melting furnace 10. It is like that.
An example of a method for monitoring the furnace bottom will be described with reference to FIG. 6. During the normal operation (S 10), the temperature distribution on the surface of the furnace bottom iron skin is periodically measured by the thermography device 30 (S 11). From the measured temperature distribution, it is determined whether the high temperature region is local or wide area (S12), and if it is wide area, it is obtained by the various measuring instruments provided in the melting furnace 10. The operation state is confirmed from other measurement factors (S13). Examples of the measurement factor include a detected slag temperature (S14), a calculated slag temperature (S15), a cooling water heat quantity (S16), a stamp temperature (S17), and the like. From these measurement factors, it is determined whether or not a high temperature region appears in a wide area because the operating temperature of the melting furnace is high (S18). If it is determined that the operating temperature is high, the control of the DC power source 13 is performed. Then, the operating temperature is lowered by increasing the main electrode, increasing the amount of work to be processed, etc. (S19) and returning to normal operation.

Here, when it is determined that the temperature rise in a wide area is not caused by the high operating temperature of the melting furnace, it is determined that there is a high possibility that the refractory brick 18 on the furnace bottom 17 is floating as a whole ( S20), the operation of the furnace is stopped (S21), and the refractory brick 18 is repaired or replaced (S22).
On the other hand, when it is determined from the temperature distribution image obtained by the thermography device 30 that the high temperature region is local, it is determined that there is a high possibility that the refractory bricks 18 in the furnace bottom 17 are partially floating. Then, the operation of the furnace is stopped (S24), and the refractory brick 18 is repaired or replaced (S25).
Thus, by detecting the high temperature region from the measured temperature distribution, it is possible to accurately grasp problems such as erosion of the refractory material of the furnace bottom 17 and lifting even during operation. It is possible to prevent the deformation and dropout of 16.

  Since the present invention can detect the temperature of the furnace bottom in a wide range and with high accuracy, it can be used in a plasma melting furnace, an electric resistance melting furnace, a burner melting furnace, a swirling melting furnace, a reflection melting furnace, etc. It can be applied to any melting furnace.

It is a whole block diagram which shows the side cross section of the melting furnace provided with the furnace bottom monitoring apparatus which concerns on the Example of this invention. It is a sectional side view which shows the outline of the furnace bottom part provided with the furnace bottom monitoring apparatus which concerns on a present Example. It is a top view which shows the outline of the furnace bottom part provided with the furnace bottom monitoring apparatus shown in FIG. It is a schematic diagram for demonstrating the emissivity correction method. It is a flowchart which shows the emissivity correction | amendment process in a present Example. It is a flowchart which shows the furnace bottom monitoring process of the melting furnace in a present Example. It is a whole block diagram which shows the cross section of the conventional melting furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plasma melting furnace 11 Main electrode 12 Furnace bottom electrode 14 Furnace main body 15 Amorphous refractory material 16 Iron skin 17 Furnace bottom 18 Refractory brick 22 Molten slag 23 Molten metal 25 Outlet 30 Thermography device 31 Black body 32 Target 40 Control device

Claims (10)

A thermography device is installed at a position including the furnace bottom surface of the melting furnace in the measurement range, and a black body with an emissivity set to a value of 1.0 is provided in the vicinity of an arbitrary temperature measurement point included in the measurement range. Every
Setting the reference emissivity to a value of 1.0 in advance, and measuring the black body temperature from the radiant energy of the black body with the thermography device;
A step of obtaining an emissivity at which a measurement point temperature measured from the radiant energy of the measurement point by the thermography device matches the black body temperature;
Setting the obtained emissivity to the emissivity of the measurement range, and measuring the temperature distribution of the measurement range by the thermography device,
The black body furnace bottom temperature measuring how to wherein providing the heart located in the furnace bottom surface corresponding to the line connecting the tapping port of the melting furnace in the melting furnace. A thermography apparatus is installed at a position including the furnace bottom surface of the melting furnace in the measurement range, and a plurality of black bodies having an emissivity of 1.0 are set in the vicinity of any temperature measurement point included in the measurement range. Providing a reference emissivity to a value of 1.0 in advance, and measuring the black body temperature from the radiant energy of the plurality of black bodies with the thermography device;
A step of obtaining an emissivity at which a measurement point temperature measured from the radiant energy of the measurement point by the thermography device matches the black body temperature;
Setting the obtained emissivity to the emissivity of the measurement range, and measuring the temperature distribution of the measurement range by the thermography device,
A plurality of the black bodies are provided on a concentric circle with the center position of the melting furnace as a central axis, or a plurality of black bodies are provided in the radial direction of the melting furnace, and the temperature distribution of the furnace bottom surface corresponding to the plurality of black bodies is determined. 2. The furnace bottom temperature measuring method according to claim 1, wherein the temperature is measured. The furnace bottom temperature measuring method according to claim 1 or 2, wherein a selected wavelength of the thermographic apparatus is within a range of 8 to 14 µm. In the bottom monitoring method of the melting furnace using the bottom temperature measuring method according to claim 1 or 2 ,
A melting furnace comprising: a step of detecting a high temperature region showing a higher temperature than during normal operation based on the measured temperature distribution; and a step of detecting an abnormality of the furnace bottom based on the detected high temperature region. Furnace bottom monitoring method. Determining whether the high temperature area detected in the high temperature area detection step is local or wide area; and
When it is determined that the high-temperature region is wide-area, determining whether the furnace temperature of the melting furnace is higher than the appropriate temperature based on other measurement factors;
And a step of determining that an abnormality has occurred in the refractory material at the bottom of the furnace when the furnace temperature is appropriate or the high temperature region is local. 4. A method for monitoring the bottom of a melting furnace according to 4 . A thermography device installed at a position including the bottom surface of the melting furnace in the measurement range, and a black body in which the emissivity provided in the vicinity of any temperature measurement point included in the measurement range is set to a value of 1.0 And comprising
Storage means for storing a black body temperature measured by the thermography apparatus with a reference emissivity set to a value of 1.0, and radiation whose measurement point temperature measured by the thermography apparatus matches the black body temperature An emissivity correction means for determining a rate, and a control device,
Set the emissivity obtained by the control device to the emissivity of the measurement range, measure the temperature distribution of the measurement range by the thermography device,
It said black body, the melting furnace hearth temperature measuring device you characterized in that provided on the furnace bottom surface corresponding to the line connecting the tapping port of the melting furnace from cardiac position within. A thermography device installed at a position including the bottom surface of the melting furnace in the measurement range, and a black body in which the emissivity provided in the vicinity of any temperature measurement point included in the measurement range is set to a value of 1.0 And comprising
Storage means for storing a black body temperature measured by the thermography apparatus with a reference emissivity set to a value of 1.0, and radiation whose measurement point temperature measured by the thermography apparatus matches the black body temperature An emissivity correction means for determining a rate, and a control device,
Set the emissivity obtained by the control device to the emissivity of the measurement range, measure the temperature distribution of the measurement range by the thermography device,
7. The furnace bottom temperature measuring device according to claim 6, wherein the thermography device is disposed at a position off the bottom of the furnace bottom. A thermography device installed at a position including the furnace bottom surface of the melting furnace in the measurement range, and a plurality of black bodies having an emissivity set to 1.0 provided in the vicinity of an arbitrary temperature measurement point included in the measurement range And comprising
Storage means for storing a plurality of black body temperatures measured by the thermography apparatus with a reference emissivity set to a value of 1.0, and a measurement point temperature measured by the thermography apparatus match the black body temperature An emissivity correction means for obtaining an emissivity to be
Set the emissivity obtained by the control device to the emissivity of the measurement range, measure the temperature distribution of the measurement range by the thermography device,
Wherein the plurality of black body, or providing a plurality on a concentric circle whose center axis the center position of the melting furnace, or the melting furnace hearth temperature measuring device you characterized by providing a plurality in the radial direction of the. The furnace bottom temperature measuring device according to claim 6, 7 or 8, wherein a selected wavelength of the thermographic device is within a range of 8 to 14 µm. In the bottom monitoring device of the melting furnace using the bottom temperature measuring device according to claim 6 or 7 or 8 ,
The control device comprises means for detecting a high temperature region showing a higher temperature than during normal operation based on the measured temperature distribution, and means for detecting an abnormality in the furnace bottom based on the detected high temperature region. A furnace bottom monitoring device for a melting furnace.

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