JP2002081992A - Plasma ash melting furnace and method for operating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma ash melting furnace capable of melting incineration ash under a constant condition so as not to generate overpower or the shortage of power. SOLUTION: A plasma arc type ash melting furnace 1 has a furnace chamber 6 surrounded by its inner wall 11. A plasma device which is equipped with the main electrode 4 arranged on the side of the furnace chamber 6, the furnace bottom electrode 7 arranged to a furnace bottom wall 5, a DC power supply 8 and the like, is provided in the ash melting furnace 1. The main electrode 4 is provided through the ceiling wall 3 of the melting furnace main body 2 to be arranged in a suspended state and is supported by a lift device 15 so as to be made movable up and down in the furnace chamber 6. A monitoring window 16 is provided to the melting furnace main body 2 through the inner wall 11, and an infrated camera 17 measuring the arc length of plasma arc is arranged outside the viewing window 16. The arc length can be made constant by analyzing the image of the infrated camera 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma type ash melting furnace in which incinerated ash such as refuse is melt-processed and turned into slag, and the ash furnace body is reduced to an incinerated ash amount. The present invention relates to a plasma type ash melting furnace which can be stably operated correspondingly and a method of operating the same.

[0002]

2. Description of the Related Art Ash melting furnaces are used to make effective use of refuse incineration ash. The incineration ash melted by the ash melting furnace is divided into low-boiling volatile matter, slag of metals and other components. , Detoxifying and recycling it. The need for such incineration ash melting furnaces is increasing. These ash melting furnaces use a burner-type ash melting furnace that uses heavy oil or the like as fuel to melt incinerated ash, or an ash-melting furnace that uses electricity as a heat source, such as an electric resistance ash melting furnace or a plasma ash melting furnace. What melts is known.

FIG. 10 shows a conventional plasma arc type ash melting furnace 51, in which a furnace chamber 56 surrounded by a melting furnace body 52 is provided. The ash melting furnace 51 is provided with a plasma device including a main electrode 54, a furnace bottom electrode 57, a DC power supply 58, and the like. The main electrode 54 is provided through a ceiling wall 53 of the melting furnace main body 52. Together with the lifting device 65
, The furnace chamber 56 can be moved up and down. At the lower end of the main electrode 54, a furnace bottom electrode 57 is provided on a furnace bottom wall 55 facing the tip, and a DC power supply 58 for plasma generation is connected between these electrodes 54, 57. The melting furnace body 52 has an outer wall covered with an iron shell 60, an inner wall 61 is formed of a refractory material such as brick, and a slag port 68 serving as a discharge port of a molten slag 63 is provided on a peripheral wall portion of the melting furnace body 52. The slag port 68 is connected to a slag gutter 69. A mold 71 placed on a slag conveyer 70 is provided below the tip of the slag gutter 69.

With such a configuration, incineration ash is introduced into the furnace chamber 56 of the ash melting furnace 51 from an incineration ash inlet (not shown) onto the furnace bottom wall, and the furnace chamber 56 of the ash melting furnace 51 is reduced in a reducing atmosphere. In this state, the voltage is applied by the DC power supply 58 to the electrodes 54,
57. Then, a plasma arc is generated between the electrodes 54 and 57, and the incinerated ash is heated and melted to form a slag 63, and a metal component contained in the incinerated ash is melted to become a molten metal 64 and sinks to the furnace bottom. . Molten slag 6
When 3 accumulates in the furnace bottom and reaches the height of the slag port 68, the slag 63 overflows from the slag port 68, passes through the slag chute 69, and is supplied to the mold 71, and the slag 63 is cooled.

[0005]

During operation of the ash melting furnace,
Since the main electrode of the plasma electrode is consumed, it is necessary to lower the main electrode at a constant speed by an elevating device by the consumed amount. Therefore, even if an attempt is made to measure the arc length of the plasma arc in the furnace chamber using a visible camera or the like, the light generated by the plasma arc is blocked by dust floating in the furnace, and the arc length of the plasma arc cannot be grasped during operation. . Therefore, the amount of electrode consumption is determined based on experience values, but this has problems in individual differences and accuracy,
If the arc length becomes long after continuous operation for a long time, the temperature of the ceiling refractory becomes high and the efficiency of heat input to the slag decreases.
Conversely, if the main electrode sinks below the slag surface, the liquid surface will be at a low temperature, resulting in poor slag removal.

When the amount of incinerated ash to be introduced into the furnace chamber of the ash melting furnace is different, it is necessary to adjust the output of the plasma electrode accordingly. When the electric power becomes excessive due to a malfunction of the gas supply unit or the like, the operation is performed at a high temperature, and the life of the refractory material forming the furnace chamber is shortened. Conversely, when the power is insufficient, low-temperature operation is performed, the slag blocks the slag outlet, and the ash melting furnace becomes inoperable.

[0007] There is also a method of empirically judging the color and viscosity of the molten slag discharged from the slag gutter of the melting furnace main body from an image of a monitoring camera. That is, if the color of the molten slag is white, it is determined that the temperature of the furnace chamber is high, and the temperature of the furnace chamber is lowered.If the temperature of the molten slag is red, it is determined that the temperature of the furnace chamber is low, and the temperature of the furnace chamber is determined. Make it higher. When the viscosity of the molten slag is high, the temperature of the furnace chamber is raised because the temperature is low, and when the viscosity of the molten slag is low, the temperature of the furnace chamber is lowered because the temperature is high. It has been done by experience. Since this method is also based mainly on the experience of the operator, there are individual differences, and the ash melting furnace cannot be operated at a constant rate. Furthermore, the temperature of the slag can be measured with a radiation thermometer, but since the slag flowing down from the slag gutter is measured, the properties of the slag vary depending on the state of the slag at that time. Fluctuates, and the measurement points of the radiation thermometer often shift.

The present invention has been made in view of such circumstances, and in order to melt incinerated ash to form slag, constant conditions, that is, a constant voltage (constant voltage) of the plasma electrode so that there is no overpower or insufficient power. Arc length)
If the melting temperature is low based on the voltage without changing the temperature of each part, the slag melting temperature is increased by flowing more current to the plasma electrode, and if the melting temperature is higher, the slag is melted by flowing less current to the plasma electrode. An object of the present invention is to provide a plasma type ash melting furnace capable of lowering a temperature and a method of operating the same.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a furnace body into which incineration ash is charged, and a plasma electrode comprising a main electrode and a furnace bottom electrode disposed in the furnace body. In a plasma type ash melting furnace in which the incinerated ash is heated by the plasma arc of the plasma electrode to form a slag, a transmission window for transmitting infrared rays is provided on a furnace wall of the furnace body, and a vicinity of the transmission window is provided. And a plasma ash melting furnace characterized in that a plasma arc at the tip of the main electrode is analyzed by the image of the infrared camera through the transmission window. In the plasma ash melting furnace, the wavelength of the infrared camera may be 3 μm or more.

[0010] Further, in order to achieve the above object, the present invention provides a plasma type ash in which incinerated ash is introduced into a furnace chamber of a furnace body, and the incinerated ash is heated and melted by a plasma arc to generate slag. In the operation method of the melting furnace, the lower end of the main electrode is obtained by analyzing the plasma arc with the image of the infrared camera, and the chamber of the plasma arc is so set that the length of the arc length is a fixed value or within a predetermined range. The main electrode arranged inside is moved up and down. The method of operating the plasma type ash melting furnace is characterized in that the height of the slag surface is determined by the position of a scale or a refractory brick provided on the furnace wall of the furnace chamber based on an image of a visible camera capable of monitoring the furnace chamber. And the arc length of the plasma arc may be determined to adjust the current value and the amount of power of the plasma electrode.

Further, the present invention comprises a furnace main body into which incineration ash is charged, and a plasma electrode comprising a main electrode and a furnace bottom electrode provided in the furnace main body, and the plasma arc of the plasma electrode forms In a plasma type ash melting furnace for heating incinerated ash to form slag, a radiation thermometer for measuring the temperature of slag in the furnace chamber is provided. In this plasma type ash melting furnace, a two-color radiation thermometer that measures the temperature of the molten slag with two wavelengths of the radiation thermometer of 3 μm or more can be provided. Further, the present invention, in order to achieve the above object, a melting furnace body provided with a furnace chamber into which incineration ash is charged,
A plasma device provided with a furnace bottom electrode provided at the bottom of the furnace chamber and a main electrode provided inside the furnace chamber, wherein the slag is formed by heating the incinerated ash by generating a plasma arc of the plasma device. In a method of operating a plasma type ash melting furnace, a radiation thermometer for measuring the temperature of slag in the furnace chamber is used. When the temperature of the slag is lower than a predetermined set value or within a predetermined range, the plasma electrode When the temperature of the slag is higher than a certain set value or within a predetermined range, the amount of current flowing to the plasma electrode can be reduced. Further, in order to achieve the above object, the present invention provides a melting furnace body provided with a furnace chamber into which incineration ash is charged, a furnace bottom electrode provided at the bottom of the furnace chamber, and a furnace bottom electrode disposed on the furnace chamber side. A plasma device provided with a main electrode, a discharge port for discharging the slag melted by heating the incinerated ash by generation of a plasma arc of the plasma device, and a slag disposed from the discharge port are accommodated. In the plasma type ash melting furnace provided with the container, a radiation thermometer for measuring the temperature of the slag contained in the container can be provided near the container. The plasma type ash melting furnace of the present invention may be a two-color radiation thermometer that measures the temperature of the molten slag at two wavelengths of 3 μm or more of the radiation thermometer. Further, the present invention provides a melting furnace body provided with a furnace chamber into which incineration ash is charged, a plasma provided with a furnace bottom electrode provided at the bottom of the furnace chamber and a main electrode provided on the furnace chamber side. A plasma including an electrode, a discharge port for discharging the slag melted by heating the incinerated ash by generation of a plasma arc of the plasma device, and a container for accommodating the slag disposed from the discharge port. In the method of operating the ash melting furnace, the slag accumulated in the container is processed by an image of an infrared camera, a site having the highest temperature of the slag is searched, and the temperature of the slag of the portion is measured by a radiation thermometer, When the measured temperature is lower than the set value, the amount of current flowing to the plasma electrode can be increased.

Further, in order to achieve the above object, the present invention comprises a furnace main body into which incineration ash is charged, and a plasma electrode comprising a main electrode and a furnace bottom electrode disposed in the furnace main body. In the plasma type ash melting furnace in which the incinerated ash is heated by the plasma arc of the plasma electrode and turned into slag,
If the slag temperature in the furnace chamber is higher than a set value or within a predetermined range, reduce the current and electric power flowing to the plasma electrode,
If the slag temperature is lower than a set value or within a predetermined range, an in-furnace temperature control device is provided for controlling the fluctuation of the slag temperature by increasing the current and the amount of electric power flowing to the plasma electrode. In this plasma type ash melting furnace, the furnace temperature control device calculates a preceding signal focusing on the change tendency of the slag temperature, and changes the current and the electric energy of the plasma electrode by using the signal. A control unit configured to reduce the fluctuation range of the temperature of the furnace chamber slag can be provided. In addition, this plasma ash melting furnace,
The in-furnace temperature control device creates a model for predicting a slag temperature at a certain time ahead from time-series data of the slag temperature in the furnace chamber, and calculates the current and the electric power of the plasma electrode using the predicted value of the model. By changing the control unit, a control unit configured to reduce the fluctuation range of the temperature of the slag in the furnace chamber can be provided. Further, in this plasma type ash melting furnace, the furnace temperature control device includes a thermometer that detects a slag temperature flowing through the slag outlet, and the slag temperature of the outlet is lower than a predetermined set value. In addition, a control unit configured to increase the plasma current can be provided. Further, in this plasma type ash melting furnace, when the in-furnace temperature control device changes the ash input amount into the furnace chamber, the plasma current and the electric power are adjusted according to the changed processing amount. A control unit can be provided. Further, in this plasma type ash melting furnace, when the furnace temperature control device changes the amount of ash introduced into the furnace chamber, the plasma current and the electric energy are adjusted so as to raise the temperature of the molten slag in advance. The control unit may be provided. Furthermore, the above-mentioned furnace temperature control device can be used in combination with each of the above-mentioned control units.

According to another aspect of the present invention, there is provided a furnace body into which incineration ash is charged, and a plasma electrode comprising a main electrode and a furnace bottom electrode disposed in the furnace body. In the plasma type ash melting furnace in which the incinerated ash is heated by the plasma arc of the plasma electrode and turned into slag,
If the slag temperature in the furnace chamber is higher than a set value, the amount of current and power flowing to the plasma electrode is reduced, and if the slag temperature is lower than the set value, the amount of current and power flowing to the plasma electrode is increased to increase the slag temperature. A temperature control device for controlling the fluctuation of the temperature, the furnace temperature control device calculates a preceding signal focusing on the change tendency of the slag temperature, and using the signal, the current and electric power of the plasma electrode. And a controller for reducing the fluctuation range of the temperature of the furnace chamber slag by changing the furnace chamber, and a model for predicting the slag temperature at a certain time ahead from the time series data of the slag temperature in the furnace chamber, A control unit configured to reduce the fluctuation range of the temperature of the slag in the furnace chamber by changing the current and the electric energy of the plasma electrode using the predicted value of the slag; A control unit configured to increase the plasma current when the temperature of the slag of the slag is lower than a predetermined set value, the control unit including a thermometer that detects a temperature of the slag flowing through the slag port, and the furnace temperature control device. However, when changing the amount of ash introduced into the furnace chamber, a control unit that adjusts the plasma current and the power amount according to the changed processing amount, and the furnace temperature control device is moved into the furnace chamber. And a control unit for adjusting the plasma current and the electric energy so as to raise the temperature of the molten slag in advance when changing the ash input amount of the slag.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for operating an ash melting furnace according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a plasma arc ash melting furnace 1 according to the present invention.
The ash melting furnace 1 has a furnace chamber 6 surrounded by an inner wall 11, and the inner wall 11 is formed of a heat-resistant material such as a heat-resistant brick. The ash melting furnace 1 includes a plasma apparatus including a main electrode 4 provided on the furnace chamber 6 side, a furnace bottom electrode 7 provided on a furnace bottom wall 5 of the furnace chamber 6, a DC power supply 8, and the like. Is provided. The main electrode 4 is disposed so as to hang down through the ceiling wall 3 of the melting furnace main body 2, and is configured to be able to move up and down in the furnace chamber 6 by being supported by the elevating device 15. The main electrode 4 is made of metal or graphite, and has a cylindrical shape in which a passage for generating a plasma gas is formed. At the lower end of the main electrode 4, a furnace bottom electrode 7 is installed on a furnace bottom wall 5 facing the tip, and a DC power source 8 for plasma generation is connected between these electrodes 4 and 7. The DC power supply 8 has + connected to the furnace bottom electrode 7 side and − connected to the main electrode 4 side.

A viewing window 12 is provided on the wall of the melting furnace body 2, a visible camera 33 is provided near the viewing window 32, and the height of the inner wall 11 is measured on the inner wall 11. Is displayed. The visible camera 13 can measure the liquid level of the slag by looking at the scale. FIG. 2 is a sectional view of the melting furnace main body 2 of FIG. 1 as viewed from another angle. As shown in FIG.
1 and an inspection window 16 penetrating through the steel shell 10, the inspection window 1 is provided.
An infrared camera 17 is provided outside the camera 6. The wavelength of the infrared camera 17 can be 3 μm or more, but preferably 8 μm or more. This infrared camera 1
7 is arranged toward the tip of the main electrode 4 and has a viewing window 16.
The arc length of the plasma arc can be observed via a monitor via the monitor. As shown in FIG. 3, an observation window 12 is provided on the ceiling wall 3 of the melting furnace main body 2.
Is disposed almost directly above the upper portion of the slag port 18 on the entrance side. Above the viewing window 12, a radiation thermometer 13 is provided, and a radiation thermometer having a long wavelength of 3 μm or more can be used. In the present embodiment, a two-color radiation thermometer that detects temperature at two wavelengths is used. Used. The radiation thermometer 13 can measure the temperature near the entrance of the slag port 18.

A cooling jacket (not shown) is provided around the inner wall 11 of the melting furnace main body 2, and a slag port 18 as an outlet for the molten slag 23 is provided on the lower wall of the melting furnace main body 2. The slag port 18 is connected to a slag gutter 19.
The slag port 18 and the slag gutter 19 are formed of a refractory material. A slag conveyor 21 is located immediately below the tip of the slag gutter 19.
A mold 22 mounted on the upper surface is provided. The mold 22 collects the molten slag 23 flowing down from the slag gutter 19.

As shown in FIG. 4, a mold 22 for collecting the molten slag 23 flowing down from the slag gutter 19 is provided near the tip of the slag gutter 19, that is, on both walls 25 and 26 of the slag conveyer 21. A plurality of viewing windows 27, 28 are provided at positions where the slag collection surface can be seen, and radiation thermometers 29, 30 are disposed in the viewing windows 27, 28, respectively.
A two-color thermometer that detects temperature by wavelength is used. The radiation thermometers 29 and 30 detect the temperature of the slag recovery surface of the mold 22 described above.

FIG. 5 shows an example of a control system for controlling the furnace temperature for controlling the ash melting furnace 1. The in-furnace temperature control device 35 provided in the ash melting furnace 1 receives measurement values from radiation thermometers 29 and 30 for measuring the slag temperature of the slag port 18, and uses the infrared camera 17 and the visible camera 33 and the like. In addition to the measured temperature of the furnace chamber slag,
The control unit of the hopper (not shown) is configured to input information on the amount of ash introduced into the furnace chamber 6. The ash melting furnace 1 is provided with a number of ash input hoppers and the like, which are not described, and a large number of control devices for controlling plasma and the like, but detailed descriptions thereof are omitted. I do.

Next, the operation of the embodiment of the present invention will be described. As shown in FIG. 1, incineration ash was injected into the furnace chamber 6 of the ash melting furnace 1 from an inlet (not shown) for incineration ash on the furnace bottom wall, and the furnace chamber 6 of the ash melting furnace 1 was brought into a reducing atmosphere. In this state, a voltage is applied between the electrodes 4 and 7 by the DC power supply 8.
Then, a plasma arc is generated between the electrodes 4 and 7, the atmosphere in the furnace chamber 6 becomes 1000 ° C. or more, and the incineration ash is melted. The incinerated ash melts to form slag 23, and the metal component contained in the incinerated ash melts to form molten metal 24, which sinks to the furnace bottom. When the supernatant molten slag 23 accumulates at the furnace bottom and reaches the level of the slag port 18, the slag 23 overflows from the slag port 18, passes through the slag gutter 19, and passes through the slag conveyor 2.
The slag 23 is supplied to the mold 22 which is a collection container provided in the slag 1, and the slag 23 is air-cooled.

During operation of the ash melting furnace 1, an infrared camera 17 shown in FIG. 2 takes an image of the tip of the main electrode 4 of the plasma electrode. The infrared camera 17 is for photographing the shape of the plasma arc, and the shape of the plasma arc can be viewed on a monitor. Therefore, the infrared camera 17
The monitor captures the image captured by the computer, analyzes the arc shape, and derives the arc length. During the melting of the incinerated ash, the main electrode 4 is moved up and down by the lifting device so that the length of the arc length is always maintained at a constant value. ), And thereby keep the temperature of each part constant. Thus, the main electrode 4
By making the height above the slag surface constant, the arc length of the plasma arc can be maintained at a constant length.

When the slag 23 is discharged from the slag port 18, the liquid level of the slag 23 is equal to the height of the slag port 18. The height of the lower end of the main electrode 4 is set to the infrared camera 17.
By determining the mounting angle of the infrared camera 17 and the position of the main electrode 4, the arc length can be accurately obtained without analyzing the shape of the plasma arc. The visible camera 33 shown in FIG. 1 can see the scale displayed on the inner wall 11 of the molten slag 23, so that the liquid level of the slag 23 can be measured. Therefore,
As described above, the height of the lower end of the main electrode 4 is adjusted by the infrared camera 1.
7, the arc length can be obtained without analyzing the plasma arc.

As described above, by keeping the distance between the main electrode 4 and the surface of the slag 23, ie, the arc length of the plasma arc, the voltage of the plasma electrodes 4 and 7 can be kept constant, and the melting of the slag 23 can be achieved. If it is determined that the temperature is lower than the set value, the temperature of the molten slag 23 is increased, and the amount of current of the plasma electrodes 4 and 7 is increased via a control device or the like, so that the amount of heat generated by the plasma electrodes 4 and 7 is increased. Then, the incinerated ash or the molten slag 23 can be heated. If it is determined that the melting temperature of the slag 23 is higher than the set value,
By reducing the amount of current of the plasma electrode via a control device or the like, the calorific value can be reduced, and the melting temperature of the molten slag 23 can be reduced.

During the operation of the ash melting furnace 1, the infrared camera 17 shown in FIG. 2 takes an image of the tip of the main electrode 4 of the plasma electrode. The infrared camera 17 measures the arc length of the plasma arc, that is, the distance between the main electrode 4 and the surface of the molten slag 23. The monitor 20 displays an image taken by the infrared camera 17 to analyze the arc length. I do. During the melting of the incineration ash, the main electrode 4 is moved up and down by the elevating device so that the length of the arc is always maintained at a constant length. As described above, by maintaining the arc length of the plasma arc at a constant length, the voltage of the plasma electrodes 4 and 7 can be kept constant. In the atmosphere in the furnace chamber 6 of the ash melting furnace 1, suspended matter and low-boiling-point steam are generated. However, the wavelength of the infrared camera 17 is hardly affected by these, and the arc length can be measured. .

The radiation thermometer 33 shown in FIG. 1 can measure the temperature of the molten surface of the molten slag 23. Slug 2
3 is lower than a set value or within a predetermined range, in order to raise the temperature of the molten slag 23, the amount of current of the plasma electrodes 4 and 7 is increased through the control device 31 so that the plasma electrodes 4 and 7 are increased. 7, the amount of heat generated is increased by increasing the amount of current flowing to the incineration ash or the molten slag 23. At this time, the plasma electrodes 4
The voltage of 7 is constant. If the melting temperature of the slag 23 is higher than a set value or within a predetermined range, the controller 31
By reducing the amount of current of the plasma electrode through the above, the calorific value can be reduced, and the melting temperature of the molten slag 23 can be lowered. The radiation thermometer 33 is less susceptible to floating substances and low boiling point steam in the furnace chamber 6 of the ash melting furnace 1,
Temperature can be measured. Particularly, in the present embodiment, since the two-color radiation thermometer 33 is used, it is possible to more accurately measure the melting temperature of the slag.

As shown in FIG. 4, the slag slag 23 flowing down from the slag gutter 19 is collected by the mold 22 and spreads around the drop point on the mold 22. Since the radiation thermometers 29 and 30 disposed on the walls 25 and 26 are spread over the surface of the mold 22 to measure the temperature of the slag, the radiation slag 23 to be measured does not exist at the position to be measured. The state disappears. That is, unlike the conventional case, the flow path of the slag slag changes and the measurement point of the slag slag of the radiation thermometer does not shift. In the present embodiment, the locations of the highest temperature of the waste slag 23 are measured by the radiation thermometers 29 and 30. These radiation thermometers 29 and 30 are used supplementarily, and when the measured value is equal to or lower than a certain temperature (for example, at a temperature that hinders slag slagging), the current value of the plasma electrodes 4 and 7 is increased. In this way, the slag is reliably drained. These radiation thermometers 29, 30
Is hardly affected by suspended matter and low boiling point vapor near the slag conveyor 21 and can measure the temperature of the molten slag 23. Further, since the two-color radiation thermometers 29 and 30 are used, the melting temperature of the slag can be measured more accurately. It is to be noted that a more accurate temperature can be determined by analyzing the highest slag portion in the mold 22 with an infrared camera and measuring the slag temperature of this high portion with a radiation thermometer.

Next, a method of controlling the slag temperature of the ash melting furnace 1 will be specifically described. Furnace temperature controller 35
The controller 36 controls the plasma electrode 4, which is the control target 37, based on a preset slag temperature set value.
7. Operate the current and energy of 7. As an example, the controller 4
FIG. 6 shows a method of controlling the control target 37 using a signal in which the phase of the slag temperature in the furnace is advanced by 1b. A in FIG.
In the diagram shown in FIG. 5, the vertical axis indicates the temperature T, the horizontal axis indicates time,
The curve shows the fluctuation of the slag temperature T. When the slag temperature T rises to the maximum set temperature a, the plasma electrodes 4, 7
The current and power amount of the plasma electrodes 4 and 7 are increased when the temperature and the power amount of the plasma electrodes 4 and 7 decrease to the minimum set temperature b. FIG. 6B shows the current set values of the plasma electrodes 4 and 7 at that time. The conventional current set value is UP when the slag temperature T is lower than the minimum set temperature b.
If the state is (large) and the temperature is higher than the maximum set temperature a, DOWN
(Small) state, and M in the state between the set temperatures a and b
An IDL (reference) state is set, and control is performed in three stages.

However, according to this control method, the current set value is changed after exceeding the set range a to b.
The fluctuation range of the slag temperature becomes large. Then, as a function of the relationship between the temperature and the time indicated by the slag temperature T, this is differentiated to obtain the slope of the temperature T as shown by a solid line T ′ in FIG. 6C, and T + kT in FIG. As shown in ′, the current set value of the plasma electrodes 4 and 7 is changed by a waveform (curve) with the phase of the temperature T advanced. It is shown in FIG. By controlling the plasma electrodes 4 and 7 with this current set value, the range of fluctuation of the slag temperature can be reduced.

The radiation thermometers 29 and 30 for detecting the temperature of the slag flowing down from the slag gutter 19 are provided with a furnace temperature controller 35.
The controller 38 compares the actual slag temperature of the slag gutter 19 with the set value, and varies the current and the electric power of the plasma electrodes 4 and 7 as current correction values by the variation. However, since the limiter 39 is provided,
The current is limited to a certain amount or less, and the current and the electric power of the plasma electrodes 4 and 7 are increased as the current correction only when there is a possibility that the slag is solidified in the slag gutter 19. Therefore, when the slag flows down from the slag gutter 19 normally, the slag is limited to the limiter 30 and does not operate.

FIGS. 7 and 8 show details of the controller 40 for correcting the current of the plasma electrodes 4 and 7 at the time of ash injection shown in FIG. This controller 40 is required because the slag temperature decreases when the amount of incinerated ash supplied to the ash melting furnace 1 is increased. Therefore, the current amount of the plasma electrodes 4 and 7 must be increased accordingly. Because it does not become. The feature of this control method is that before the ash input amount is increased, the temperature of the molten slag is raised in advance and then the ash is input into the furnace chamber 6.
That is, the controller 40 is provided with a delay circuit.
As shown in the flow chart of FIG. 7 and the timing chart of FIG. 8, when the ash input amount is changed, the current amount of the plasma electrodes 4 and 7 is increased by the amount corresponding to the increase. At that time, a timer is set, and when the furnace slag temperature is higher than a predetermined value (upper limit) and exceeds a predetermined time,
The hopper is controlled to change the ash supply amount. As shown in the furnace slag temperature in FIG. 8, when there is no present logic, the slag temperature fluctuates greatly at the same time as the ash is charged. However, as with the present logic, the fluctuation range of the furnace slag temperature becomes small.

The prediction model controller 41a shown in FIG. 5 is a circuit for predicting the slag temperature from the past operation state of the ash melting furnace 1, and predicts the slag temperature based on the controllers 36, 38 and 40 described above. However, it is a predictive control for adjusting the current and the electric energy of the plasma electrodes 4 and 7. As shown in FIG. 9A, in normal feedback control, the control output is determined according to the difference (deviation) between the current value and the set value. In the predictive control, as shown in FIG. 9B, a predictive model for predicting a value at a certain time ahead from past time-series data is created, and the difference between the output value (predicted value) of the model and the set value is calculated. This is a method of determining the control output of the plasma electrodes 4 and 7 accordingly. With this method, the operation can be performed before the change in the state quantity appears, so that the fluctuation cycle is shortened,
The fluctuation range of the slag temperature can be reduced.

As the prediction model, for example, an autoregressive model is used. The auto-regression model is defined as a state quantity (temperature deviation = slag temperature set value−slag temperature measured value) X (t), and a state quantity X (t−τ),
X (t−2τ),..., X (t−nτ), and is expressed by the following equation.

[0032]

(Equation 1) n: order, τ: measurement cycle, a _k (k = 1,...,
n), d: Model parameters When this model is used, the time t- (n-1) is calculated from the current time.
When a value up to × τ is obtained, the time t +
The temperature deviation X (t + τ) of τ can be expressed by the following equation.

[0033]

(Equation 2) It can be seen from this equation that it is possible to predict the value one step ahead of the past time-series data. As the model parameters a _k (k = 1,..., N) and d, values that minimize the error are obtained by the least square method or the like using past experimental data. If the model parameters change during operation, it should be possible to change them sequentially online.

As described above, in this embodiment, the arc length of the plasma arc is measured using the infrared camera 17, the radiation thermometers 29, 30, and 33, the temperature of the molten slag is actually measured, and a prediction model is used. Accordingly, the temperature of the molten slag 23 in the furnace chamber 6 is not increased unnecessarily, so that the life of the refractory material of the inner wall 11 can be extended and unnecessary power consumption can be prevented. Conversely, the temperature of the molten slag 23 decreases, and the molten slag 2
3 is prevented from being hindered, and the slag 23 does not block the slag port 18.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention. In the above embodiment, a slag 23 is used by using a two-color radiation thermometer.
Was measured, but the thermometer may be a normal radiation thermometer. Further, although the infrared camera and the radiation thermometer are used together with the ash melting furnace 1, the ash melting furnace may be operated using only the infrared camera or the radiation thermometer.

[0036]

As described above, according to the present invention, since the arc length of the plasma arc is analyzed via the infrared camera, the temperature of each part in the furnace is controlled by setting the arc length to a constant length. Can be kept constant. As a result, the arc length does not fluctuate, so that the temperature of the molten slag in the furnace chamber is not increased unnecessarily, the life of the refractory material on the inner wall is extended, and unnecessary power consumption is prevented. Temperature is so low that the slag port is not blocked. Since the ash melting furnace was operated while predicting the temperature of the molten slag in the furnace chamber by using the prediction model, the fluctuation range of the temperature of the molten slag could be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a portion where a visible camera of a plasma arc ash melting furnace according to an embodiment of the present invention is disposed.

FIG. 2 is a schematic sectional view of a portion of the ash melting furnace of FIG. 1 where an infrared camera is arranged.

FIG. 3 is a schematic sectional view of a portion where another infrared camera is arranged in the ash melting furnace of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of the vicinity of a tapping gutter of the ash melting furnace of FIG.

FIG. 5 is a block diagram of a furnace temperature control device of the ash melting furnace of FIG. 1;

FIG. 6 is a diagram for explaining a method of reducing the fluctuation width of the slag temperature by advancing the phase of the slag temperature in the furnace temperature control device of FIG. 5;

FIG. 7 is a flowchart for explaining an ash input amount changing logic of the ash melting furnace of FIG. 1;

FIG. 8 is a diagram showing a time chart of changing an ash input amount of the ash melting furnace of FIG. 1;

FIG. 9A is a block diagram of normal feedback control, and FIG. 9B is a block diagram of predictive control of the present embodiment.

FIG. 10 is a schematic cross-sectional view passing through a cross section of a slag port of a conventional plasma arc ash melting furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma arc type ash melting furnace 2 Melting furnace main body 3 Ceiling wall 4 Main electrode 5 Furnace bottom wall 6 Furnace room 7 Furnace bottom electrode 8 DC power supply 10 Iron shell 11 Inner wall 12, 16, 27, 28, 32 Viewing window 13 Visible camera DESCRIPTION OF SYMBOLS 15 Elevating device 17 Infrared camera 18 Slag port 19 Slag gutter 21 Slag conveyor 22 Mold 23 Melt slag 24 Metal 25, 26 Wall 33 Visible camera 35 Furnace temperature control device 36, 38, 40 Controller 37 Control target 39 Limiter 41a Prediction model controller 41b Phase lead controller 41c Switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22B 9/22 F27B 3/28 4K001 F27B 3/08 F27D 11/08 E 4K045 3/28 11/10 4K056 F27D 11/08 21/00 Z 4K063 11/10 G 21/00 G01J 1/42 C 5/48 D G01J 1/42 H05B 7/148 B 5/48 B09B 3/00 ZAB H05B 7/148 303L (72) Invention Person Ichiro Yamashita 1-8-1 Koura, Kanazawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Yokohama Research Laboratory of Mitsubishi Heavy Industries, Ltd. (72) Inventor Minoru Ike 12-nishikicho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Heavy Industries, Ltd. Person Tetsuo Sato 12 Nishiki-cho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Heavy Industries, Ltd.Yokohama Works (72) Inventor Tatsuo Tazawa Yokohama-shi, Kanagawa Prefecture 12 Nishiki-cho, Ward Mitsubishi Heavy Industries, Ltd. Yokohama Works (72) Inventor Keita Inoue 12 Nishiki-cho, Naka-ku, Yokohama, Kanagawa Prefecture Mitsubishi Heavy Industries, Ltd. Yokohama Works F-term (reference) 2G065 AA11 AB02 BA04 BA15 BA34 BC35 CA29 DA06 2G066 AA04 AC01 AC11 AC20 BA01 BA08 BA09 BA14 BC15 BC30 CA01 CA04 CA20 3K084 AA07 4D004 AA36 BA05 CA29 CA41 CA45 CB33 DA01 DA02 DA06 DA11 4G075 AA37 AA63 AA65 BB03 CA02 CA47 EB43 EC14 FC07 4K001 BA12 BA04 DA05 DA04 4K056 AA05 BB08 CA20 FA01 FA11 FA12 FA23 4K063 AA04 AA12 BA13 CA01 CA02 FA56 FA78

Claims (17)

[Claims] 1. A plasma apparatus having a melting furnace body provided with a furnace chamber into which incineration ash is charged, a furnace bottom electrode provided at the bottom of the furnace chamber, and a main electrode provided inside the furnace chamber. A plasma-type ash melting furnace for heating the incinerated ash by the plasma arc of the plasma electrode to form a slag, wherein a transmission window for transmitting infrared rays is provided on a furnace wall of the furnace body, and a vicinity of the transmission window. A plasma-type ash melting furnace characterized in that an infrared camera is provided in the apparatus, and a plasma arc at the tip of the main electrode is analyzed based on an image of the infrared camera through the transmission window. 2. The plasma type ash melting furnace according to claim 1, wherein the wavelength of the infrared camera is 3 μm or more. 3. A method of operating a plasma type ash melting furnace in which incinerated ash is charged into a furnace chamber of a furnace body, and the incinerated ash is heated and melted by a plasma arc to generate slag. The height of the lower end portion of the main electrode is obtained by analyzing the plasma arc, and the main electrode disposed on the indoor side of the plasma arc so that the length of the arc length is constant or within a predetermined range. Method of operating a plasma type ash melting furnace in which the ash is moved up and down. 4. The height of the slag surface is determined from a scale of a furnace wall of the furnace chamber or a position of a refractory brick based on an image of a visible camera capable of monitoring the furnace chamber. The method according to claim 3, wherein the length is determined. 5. A plasma apparatus provided with a melting furnace main body provided with a furnace chamber into which incinerated ash is charged, a furnace bottom electrode provided at the bottom of the furnace chamber, and a main electrode provided inside the furnace chamber. In the plasma type ash melting furnace for heating the incinerated ash by the plasma arc of the plasma electrode to form slag, a radiation thermometer for measuring the temperature of the slag in the furnace chamber is provided. Plasma type ash melting furnace. 6. The radiation thermometer having a wavelength of 3 μm or more.
The plasma type ash melting furnace according to claim 5, which is a two-color radiation thermometer that measures the temperature of the molten slag with a wavelength. 7. A plasma apparatus provided with a melting furnace main body provided with a furnace chamber into which incineration ash is charged, a furnace bottom electrode provided at the bottom of the furnace chamber, and a main electrode provided inside the furnace chamber. And a method of operating a plasma type ash melting furnace for heating the incinerated ash by the generation of a plasma arc of the plasma device to form a slag, wherein a radiation thermometer for measuring a temperature of the slag in the furnace chamber is used. If the temperature of the slag is lower than a certain set value or within a predetermined range, the current and the amount of power flowing to the plasma electrode are increased, and if the temperature of the slag is higher than a certain set value or within a predetermined range, A method for operating a plasma type ash melting furnace, wherein the amount of current flowing to the plasma electrode is reduced. 8. A plasma apparatus provided with a melting furnace main body provided with a furnace chamber into which incineration ash is charged, a furnace bottom electrode provided at the bottom of the furnace chamber, and a main electrode provided inside the furnace chamber. And an outlet for discharging the molten slag to the outside of the furnace chamber by heating the incinerated ash by generating a plasma arc of the plasma device,
A plasma-type ash melting furnace having a container for storing the slag disposed from the discharge port, wherein a radiation thermometer for measuring the temperature of the slag stored in the container is disposed near the container. Characteristic plasma type ash melting furnace. 9. The radiation thermometer having a wavelength of 3 μm or more.
9. The plasma type ash melting furnace according to claim 8, which is a two-color radiation thermometer that measures the temperature of the molten slag with a wavelength. 10. A melting furnace body provided with a furnace chamber into which incineration ash is charged, a plasma electrode provided with a furnace bottom electrode provided at the bottom of the furnace chamber and a main electrode provided inside the furnace chamber. And a discharge port for discharging the slag melted by heating the incinerated ash by the generation of the plasma arc of the plasma device to the outside of the furnace chamber, and a container provided with the slag disposed from the discharge port for accommodating the slag. In the method of operating the ash melting furnace, processing the image of the slag accumulated in the container by an infrared camera, searching for a site of the highest temperature of the slag, measuring the temperature of the slag of the site by a radiation thermometer, An operation method of a plasma type ash melting furnace, wherein the amount of current flowing to the plasma electrode is increased when the measured temperature is lower than a set value. 11. A furnace body into which incineration ash is charged, and a plasma electrode comprising a main electrode and a bottom electrode disposed in the furnace body, and the incineration ash is heated by a plasma arc of the plasma electrode. If the slag temperature in the furnace chamber is higher than a set value or within a predetermined range, the current and electric power flowing to the plasma electrode are reduced,
If the slag temperature is lower than a set value or within a predetermined range, an in-furnace temperature control device that controls the fluctuation width of the slag temperature to be small by increasing the current and the amount of power flowing to the plasma electrode is provided. Plasma ash melting furnace. 12. The furnace temperature control device calculates a preceding signal paying attention to the change tendency of the slag temperature, and uses the signal to change a current and an electric power of the plasma electrode, thereby obtaining a slag in the furnace chamber. 12. A control unit configured to reduce a fluctuation range of the temperature of the control unit.
3. The plasma ash melting furnace according to 1. 13. The in-furnace temperature control device creates a model for predicting a slag temperature at a certain point in time from time-series data of the slag temperature in the furnace chamber, and uses the predicted value of the model to generate a model of the plasma electrode. The plasma type ash melting furnace according to claim 11, further comprising a control unit configured to reduce a fluctuation range of the temperature of the furnace chamber slag by changing a current and an electric energy. 14. The in-furnace temperature control device includes a thermometer for detecting a slag temperature flowing through a slag outlet, and when the slag temperature at the outlet is lower than a predetermined set value, the plasma current is controlled. 12. The plasma type ash melting furnace according to claim 11, further comprising a control unit configured to increase the number. 15. The control apparatus according to claim 15, wherein the furnace temperature control device includes a controller configured to adjust a plasma current and a power amount according to the changed processing amount when changing the ash input amount into the furnace chamber. The plasma type ash melting furnace according to claim 11, wherein: 16. A control wherein the in-furnace temperature control device adjusts the plasma current and the electric power so as to raise the temperature of the molten slag in advance when changing the amount of ash introduced into the furnace chamber. 2. The device according to claim 1, further comprising:
6. The plasma type ash melting furnace according to 5. 17. A furnace main body into which incineration ash is charged, and a plasma electrode comprising a main electrode and a furnace bottom electrode disposed in the furnace main body, and the incineration ash is heated by a plasma arc of the plasma electrode. In a plasma-type ash melting furnace that turns into slag, the current and power flowing to the plasma electrode are reduced if the slag temperature in the furnace chamber is higher than a set value, and the current flowing to the plasma electrode if the slag temperature is lower than the set value. A furnace temperature controller for controlling the fluctuation of the slag temperature by increasing the amount of power, the furnace temperature controller calculates a preceding signal focusing on the change tendency of the slag temperature, and A control unit that changes the current and power amount of the plasma electrode to reduce the fluctuation range of the temperature of the slag in the furnace chamber, A control unit that includes a thermometer that detects the temperature of the slag flowing through the slag port, and increases the plasma current when the temperature of the slag at the slag port is lower than a predetermined set value; and the furnace temperature control device. However, when changing the ash input amount into the furnace chamber, a control unit that adjusts the plasma current and the electric energy according to the changed processing amount, and the furnace temperature control device is inserted into the furnace chamber. A control unit that adjusts the plasma current and the electric energy so as to raise the temperature of the molten slag in advance when changing the ash input amount of the ash, and a predetermined time ahead from the time-series data of the slag temperature in the furnace chamber. A controller that creates a model that predicts the slag temperature of the furnace, and changes the current and power of the plasma electrode using the predicted value of the model to reduce the fluctuation range of the temperature of the furnace chamber slag. Equipped Plasma ash melting furnace according to claim.