JP2932876B2 - Method and apparatus for measuring molten metal surface depth in incineration ash melting furnace - 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 measuring the depth of a slag melt and a metal in a melting furnace for melting waste such as incineration ash and sewage sludge. And an apparatus.

[0002]

2. Description of the Related Art Waste such as incinerated ash of urban garbage and sewage sludge contains various inorganic and organic substances, and if these are buried as they are, serious secondary pollution is caused. In recent years, incineration ash melting furnaces have been used to detoxify such wastes. In this melting furnace, most of the waste is turned into molten slag, which is a vitreous melt, and the remainder is turned into molten metal of metal by resistance heating by applying electricity between the electrodes loaded inside, and the two are separated and externally separated. To be discharged. In order to operate the melting furnace efficiently, it is desirable that a predetermined amount of waste is sequentially charged into the melting furnace, a large amount of molten slag is continuously taken out, and a small amount of molten metal is taken out intermittently. As a condition in this case, it is necessary that the slag surface in the furnace is always kept at a predetermined position so that the height difference between the slag surface of the molten slag and the slag port is always constant.

[0003] By the way, since the upper part of this melting furnace is sealed, the position of the slag surface in the furnace cannot be known. And since the ratio of organic matter and inorganic matter contained in the waste is not known, even if a predetermined amount of waste is put into the melting furnace, the position of the slag surface fluctuates. There is a risk that molten slag may overflow from the furnace when the position of the slag surface is too high because the slag cannot be reused because the slag is clogged or the metal is mixed with the molten slag to be taken out. Further, since the position of the metal surface also fluctuated, it was not possible to judge when to remove the metal. Therefore, in order to avoid such a situation, it is required to know the position of the slag surface in the furnace and adjust the removal of the slag and metal accordingly to make the slag surface constant.

[0004]

Conventionally, in an incineration ash melting furnace having a closed upper part, there has been no method or apparatus for finding the position of the slag surface in the furnace. The present invention
It has been made to solve such a problem, and in a melting furnace in which the upper part is sealed, a method and apparatus for measuring a molten metal surface depth of a melting furnace capable of knowing a position of a slag surface in the furnace. The purpose is to gain.

[0005]

According to the method of measuring the molten metal surface depth of an incineration ash melting furnace according to the present invention, the upper part is closed, and a plurality of electrodes filled in the furnace are heated in the furnace by electric resistance heating. In the method for measuring the molten metal surface depth of an incineration ash melting furnace that melts incinerated ash, a metal wire is fed from the furnace top to a terminal plate provided at the furnace bottom at a predetermined feed rate. A predetermined voltage is applied to the wire and the terminal plate during the wire feeding, and the time until the voltage between the wire and the terminal plate during the wire feeding decreases from a predetermined applied voltage value is set to 0V. The time required for the slag surface and the metal surface to be determined with reference to the furnace top is calculated and obtained based on the wire feed amount and the time required for the voltage to change, by measuring the time until the voltage changes. The apparatus for measuring the molten metal surface depth of an incineration ash melting furnace according to the present invention is an incineration method that melts incineration ash put into the furnace by electric resistance heating of a plurality of electrodes filled in the furnace with the top closed. A wire feeder that feeds a metal wire at a predetermined feed amount from the furnace top of the ash melting furnace to a terminal plate provided on the furnace bottom, and measures a feed amount of the wire sent out by the wire feeder. An encoder, a power supply for supplying a voltage to the wire and the terminal plate, a unit for measuring a voltage between the wire and the terminal plate, and a unit for measuring a wire feed amount and a voltage measured by the encoder were measured. And calculating means for calculating the positions of the slag surface and the metal surface based on the furnace top based on the time until the voltage changes.

[0006]

In the present invention, a metal wire is fed by a wire feeder from a furnace top of a melting furnace to a terminal plate provided on the furnace bottom at a predetermined feed rate, and the wire feeder is used by an encoder. The feeding amount of the wire sent out is measured, and a predetermined voltage is applied to the wire and the terminal plate by the power supply device during the wire feeding, and the voltage between the wire and the terminal plate during the wire feeding is changed. The time until the voltage decreases from a predetermined applied voltage value and the time until the voltage becomes 0 V are measured, and the time until the voltage measured by the means for measuring the wire feed amount and the voltage measured by the encoder is changed by the arithmetic means is changed. , The positions of the slag surface and the metal surface with respect to the furnace top are calculated, so that the positions of the slag surface and the metal surface from the furnace top of the melting furnace can be known by the calculation values of the calculating means.

[0007]

FIG. 1 is a block diagram showing an apparatus for measuring the molten metal surface depth of an incineration ash melting furnace according to an embodiment of the present invention. FIG. 2 is a plan view showing the arrangement of electrodes and wires of the incineration ash melting furnace. 3 is a waveform diagram of the voltmeter of the same measuring device when the molten slag is 1400 ° C, FIG. 4 is a waveform diagram of the voltmeter of the same measuring device when the molten slag is 1500 ° C,
FIG. 5 is a graph showing the relationship between the voltage change of the voltmeter of the measuring device and the wire feeding time, and FIG. 6 shows the change in resistance between the wire fed into the incineration ash melting furnace and the terminal plate. It is a graph. In the figure, 1 is an incineration ash melting furnace, 2 is a furnace main body of the incineration ash melting furnace 1, 3 is a lid covered on the upper part of the furnace main body 2,
Numeral 4 denotes two electrodes penetrating through the lid 3 and capable of moving up and down, the tips reaching near the bottom of the furnace, 5 two incineration ash inlets provided on the lid 2, and 6 a furnace wall of the furnace body 2. Slag outlet provided in the
Reference numeral 7 denotes a metal hole provided at the bottom of the furnace wall of the furnace main body 2, and reference numeral 8 denotes a terminal plate provided at the bottom of the furnace main body 2.

Reference numeral 10 denotes a metal wire having a diameter of 4.8 mm;
Penetrates the lid 2 from the furnace top of the melting furnace 1 to the terminal plate 8 at the furnace bottom.
And a motor 13 for driving a pair of rollers 12, 12. 14 is an encoder that measures the feed amount of the wire 10 sent out by the wire feeder 11, 15 is an AC power supply that supplies a voltage to the wire 10 and the terminal plate 8, and 16 is an AC power supply between the wire 10 and the terminal plate 8. The voltmeter 17 measures the voltage. The reference 17 is based on the furnace top based on the wire feed amount of the encoder 14 and the time until the voltage measured by the voltmeter 16 decreases from a predetermined applied voltage value and reaches 0 V. The calculating means 18 calculates the positions of the slag surface and the metal surface, and a level indicator 18 displays the positions of the slag surface and the metal surface based on the calculated values of the calculating means 17.

Next, the case where the method of the present invention is carried out using the apparatus for measuring the molten metal surface depth of the incineration ash melting furnace of the above embodiment will be described with reference to FIGS. First, the incineration ash supplied from the incineration ash inlet 5 into the furnace body 2 is melted by resistance heating generated by energization between the electrodes 4 and 4 to become molten slag and molten metal, and the molten slag layer S and the molten metal layer Form M. At this time, the electrodes 4, 4 are held such that their tips keep a certain distance from the surface of the molten slag layer S. When the molten slag layer S and the molten metal layer M are thus formed in the furnace main body 2, the wire 10 is moved from the furnace top of the furnace main body 2 toward the terminal plate 8 at the furnace bottom by the wire feeder 11. The amount of feed will be sent. At this time, the encoder 14 measures the feed amount of the wire 10 sent out by the wire feeder 11 from the rotation speed of the motor 13. At the same time as sending out the wire 10,
The voltmeter 16 measures a voltage change between the wire 10 to which the predetermined voltage is applied by the AC power supply device 15 and the terminal plate 8, and the measured value of the voltmeter 16 is sent to the calculating means 17. Further, the wire feed amount measured by the encoder 14 is also sent to the calculating means 17. The calculating means 17 determines the slag based on the furnace top based on the time required for the voltage measured by the voltmeter 16 to decrease from the voltage applied to the AC power supply 15 and the time required for the voltage to reach 0 V, and the wire feed amount of the encoder 14. Calculate the position of the surface and metal surface. The level indicator 18 displays the position of the slag surface of the molten slag layer S from the furnace top of the furnace main body 2 and the position of the metal surface of the molten metal layer M from the furnace value of the furnace body 2 based on the calculated value of the calculating means 17.

As described above, the position of the slag surface and the metal surface can be obtained by the calculation means 17 from the voltage change of the voltmeter 16 and the wire feed amount of the encoder 14 by the following reason. FIG. 3 shows a voltage change of the voltmeter 16 accompanying the feeding of the wire 10 when the temperature of the molten slag in the furnace body 2 is 1400 ° C. At this time, the supply voltage of the AC power supply 15 is, for example, 74 V, and
Is in the furnace space, the voltmeter 16 indicates a no-load voltage,
The voltage gradually drops after the wire 10 reaches the slag surface of the molten slag layer S, becomes 37 V immediately before reaching the metal surface of the molten metal layer M, and becomes 0 V when it reaches the metal surface. As described above, the reason why the voltage drop gradually starts after the wire 10 reaches the slag surface of the molten slag layer S is that the resistance generated between the tip of the wire 10 in the molten slag layer S and the terminal plate 8 is as shown in FIG. As shown in FIG. 5, the tip of the wire 10 gradually decreases as approaching the terminal plate 8, and the current flowing through the circuit increases accordingly. Is generated by subtracting the voltage generated in the internal resistance.
Further, the reason why the voltage becomes 0 V when reaching the metal surface is that the resistance between the tip of the wire 10 and the terminal plate 8 is short-circuited to zero, and no potential is generated.

FIG. 5 shows the relationship between the passage of the wire 10 and the change in the voltage of the voltmeter 16 when the temperature of the molten slag in the furnace body 2 is 1400 ° C. In this figure, t0 to t1 is the time from the top of the wire to the slag surface from the furnace top, t1 to t2 is the time from the slag surface to the metal surface, and t2 to t3 is the time from the metal surface to the slag surface. The time to reach the furnace bottom is shown. Therefore, when the time point of the voltage change of the voltmeter 16 is converted from the feed amount of the wire 10, the position of the slag surface of the molten slag layer S in the furnace main body 2 (the distance from the furnace top) and the metal surface of the molten metal layer M (Distance from the furnace top). For example, as shown in FIG.
Assuming that 5 mm / s, t0 to t1 is 8 seconds, so the distance from the furnace top to the slag surface is 348 mm, and t1 to t2 is 10 seconds, so the distance from the slag surface to the metal surface, that is, the depth of the slag water is 448 mm. I understand. FIG. 4 shows a voltage change of the voltmeter 16 accompanying the feeding of the wire 10 when the temperature of the molten slag in the furnace main body 2 is 1500 ° C. In this case,
Assuming that the wire feed amount is 43.5 mm / s, t0 to t1 become 1
Because it is 1 second, the distance from the furnace top to the slag surface is 478.5m
Since m and t1 to t2 are 7 seconds, it can be seen that the distance from the slag surface to the metal surface, that is, the depth of the slag hot water is 394.5 mm.

In the above embodiment, an AC voltage is output using the AC power supply device 15. However, the present invention can be applied to a case where a DC voltage is output using a DC power supply device. Not even. In addition, a voltmeter is used to insert a resistor in the power supply unit and to detect a change in current.
Even if it is used in place of the above, it is a matter of course that the same operation and effect can be achieved only by the difference that the current gradually starts increasing after the wire 10 reaches the slag surface of the molten slag layer S.

[0013]

As described above, according to the present invention, a metal wire is fed from a furnace top of an incineration ash melting furnace to a terminal plate provided on the furnace bottom at a predetermined feed rate, A predetermined voltage is applied to the wire and the terminal plate during the wire feeding, and the time until the voltage between the wire and the terminal plate during the wire feeding decreases from a predetermined applied voltage value is 0 V. The time until the voltage was changed was calculated by calculating the position of the slag surface and the metal surface based on the furnace top based on the wire feed amount and the time until the voltage was changed. This has the effect that the positions of the slag surface of the molten slag layer and the metal surface of the molten metal layer in the incinerated ash melting furnace can be easily known.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a molten metal surface depth measuring device of an incineration ash melting furnace according to one embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of electrodes and wires of an incineration ash melting furnace.

FIG. 3 is a waveform diagram of a voltmeter of the measuring device when the molten slag is 1400 ° C.

FIG. 4 is a waveform diagram of a voltmeter of the same measuring device when the molten slag is at 1500 ° C.

FIG. 5 is a graph showing a relationship between a voltage change of a voltmeter of the measuring device and a wire feeding time.

FIG. 6 is a graph showing a change in resistance between a wire fed into an incineration ash melting furnace and a terminal plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incineration ash melting furnace 2 Electrode 6 Terminal board 10 Metallic wire 11 Wire feeder 14 Encoder 15 AC power supply 16 Voltmeter 17 Calculation means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-37479 (JP, A) JP-A-51-116903 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01F 23/24

Claims (2)

(57) [Claims] 1. A method for measuring the depth of a molten metal surface of an incineration ash melting furnace in which an upper portion is sealed and a plurality of electrodes filled in the furnace are heated by electric resistance to melt the incineration ash charged into the furnace. A metal wire is fed at a predetermined feed amount from the furnace top toward a terminal plate provided on the furnace bottom, and a predetermined voltage is applied to the wire and the terminal plate during the wire feeding, A predetermined voltage is applied between the wire and terminal board during wire feeding
Time to decrease from voltage value and time to 0V
Is measured until the wire feed amount and the voltage change.
A method for measuring a molten metal surface depth of an incineration ash melting furnace, wherein a position of a slag surface and a metal surface with respect to a furnace top is calculated and obtained based on time . 2. An incineration ash melting furnace for melting incineration ash charged into the furnace by electric resistance heating of a plurality of electrodes filled in the furnace from the top to the bottom of the furnace. A wire feeder that feeds a metal wire at a predetermined feed amount toward the terminal plate, and an encoder that measures the feed amount of the wire sent by the wire feeder,
A power supply for supplying a voltage to the wire and the terminal plate, a unit for measuring a voltage between the wire and the terminal plate, and a unit for measuring a wire feed amount and a voltage measured by an encoder.
The furnace top is determined based on the time until the measured voltage changes.
An apparatus for measuring the molten metal surface depth of an incineration ash melting furnace, comprising: calculating means for calculating the positions of the slag surface and the metal surface as reference .