JP2947043B2 - Temperature measurement method for incinerator 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 temperature in a furnace of an incineration ash melting furnace, and in particular, does not require the use of an expensive thermocouple, and furthermore, a single probe can be used to measure the molten slag in the furnace depth direction. The present invention relates to a method for measuring the temperature in a furnace of an incineration ash melting furnace capable of accurately measuring the temperature distribution of the incinerator ash.

[0002]

2. Description of the Related Art Waste such as incinerated ash and sewage sludge of municipal garbage contains various inorganic and organic substances. If these are buried as they are, serious secondary disasters are caused. Then, in recent years, in order to make such wastes non-polluting, incineration ash of waste is melted by an incineration ash melting furnace.

[0003] The refractories used for the incineration ash melting electrode, the furnace wall, and the like inserted in the incineration ash melting furnace are consumed because they come into direct contact with high-temperature molten slag and molten metal. These consumptions are greatly affected by the furnace temperature, and the higher the furnace temperature, the greater the consumption of electrodes and refractories. On the other hand, when the temperature in the furnace increases, the thermal efficiency of the furnace decreases, and the economic efficiency deteriorates.

However, on the other hand, in order to stably discharge the molten slag and the molten metal in the furnace out of the furnace, it is necessary to raise the temperature in the furnace as much as possible and reduce the viscosity of the molten slag and the molten metal. .

[0005] From the above, it is necessary to measure the furnace temperature and maintain the furnace temperature appropriately. Therefore, temperature control of the molten slag in the furnace is an essential technology. At this time, it is required to measure the temperature distribution of the molten slag in the depth direction inside the furnace.

Conventionally, as a means for measuring the temperature in the furnace, there has been a method of inserting a thermocouple covered with a heat-resistant protective tube into the furnace from the furnace top.

[0007]

However, in the above-mentioned prior art, the thermocouple used is very expensive,
In order to measure the temperature distribution of the molten slag in the depth direction inside the furnace, it was necessary to use a plurality of thermocouples having different lengths.

Accordingly, an object of the present invention is to provide an incineration method that does not require the use of an expensive thermocouple and that can accurately measure the temperature distribution of molten slag in the furnace depth direction with a single probe. An object of the present invention is to provide a method for measuring the temperature inside a ash melting furnace.

[0009]

According to the present invention, electric resistance heating is performed by an incineration ash melting electrode inserted into a furnace.
In the furnace temperature measurement method of the incineration ash melting furnace to melt the incineration ash charged in the furnace, in the incineration ash melting furnace,
While lowering the probe attached with a pair of detection electrodes at the tip, intermittently, energization to the incineration ash melting electrode intermittently, for a short time, stop, measure the impedance between the detection electrodes during this time, It is characterized in that the temperature distribution of the molten slag in the furnace depth direction is determined based on a relationship between a previously determined molten slag temperature in the furnace and an impedance between the detection electrodes. .

[0010]

A probe having a pair of detection electrodes attached to its tip is inserted into a molten slag in a furnace with a voltage applied between the detection electrodes, and the impedance between the detection electrodes is measured. Since the impedance between the electrodes for detection changes depending on the temperature of the molten slag, if the relationship between the temperature of the molten slag and the impedance between the electrodes for detection is determined in advance, the temperature of the molten slag in the furnace depth direction can be obtained. The distribution can be measured accurately without using a thermocouple or the like.

[0011]

Next, an embodiment of a method for measuring the temperature in a furnace of an incineration ash melting furnace according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a method for measuring the temperature in a furnace of an incineration ash melting furnace according to the present invention, and FIG.
FIG. 3 is a perspective view of a probe used in the present invention.
FIG. 4 is a graph showing the relationship between the electrode voltage and electrode current and the feed amount of the probe, FIG. 4 is a graph showing the relationship between the inter-electrode impedance and the feed amount of the probe, and FIG. 5 is the relationship between the inter-electrode impedance and the molten slag temperature. FIG.

In FIG. 1, 1 is a molten metal outlet 1
A, an incineration ash melting furnace having a molten slag outlet 1B and an incineration ash inlet 1C, 2 is a pair of electrodes for incineration ash melting inserted into the incineration ash melting furnace 1, 3 is a power supply for the electrode 2, 4 is ,
The molten metal at the bottom of the incineration ash melting furnace 1, 5 is the molten metal 4
The upper molten slag, 6 is unmelted slag on the molten slag 5, and 7 is a rod-shaped coating material 8 made of ceramic or the like having excellent heat resistance and electrical insulation, as shown in FIG. A probe 10 including a pair of detection electrodes 9 inserted into the covering member 8 so that the lower end protrudes from the lower surface,
A sending device for the probe 7, a detecting power supply 11 for applying a detecting voltage to the detecting electrode 9 of the probe 7, a voltmeter 12, and an ammeter 13.

Reference numeral 14 denotes an impedance calculating means for calculating the impedance between the electrodes 9 in the depth direction inside the furnace in accordance with a signal indicating the feed amount of the probe 7 from an encoder described later. And an encoder 16 for sending a signal indicating the feed amount of the probe 7 to the impedance calculating means 14 connected to the furnace, and a melting slag temperature calculating means 16 in the furnace. Based on the impedance in the depth direction (FIG. 4) and the relationship between the molten slag temperature and the impedance between the electrodes 9 (FIG. 5) stored in advance, the temperature of the molten slag in the furnace depth direction is determined. Calculate. Reference numeral 17 denotes display means for displaying the temperature distribution of the molten slag in the furnace depth direction calculated in this manner.

FIG. 3 shows that the temperature of the molten slag in the furnace is 1400 ° C.
7 is a graph showing the relationship between the probe feed amount and the voltage and current values obtained by the voltmeter 12 and the ammeter 13 in the case of FIG. The supply voltage of the detection power supply 11 at this time is 15
V. As is apparent from FIG. 3, when the probe 8 is in the space in the furnace, the voltmeter 12 indicates a no-load voltage and the current is almost 0 A. When the probe 8 descends and the electrode 9 comes into contact with the surface of the molten slag 5, the voltage between the electrodes 9 starts to decrease (A in FIG. 3), and when it comes into contact with the molten metal 4, the voltage between the electrodes 9 becomes almost 0 V ( D) in FIG. The voltage between the electrodes 9 in the molten slag is A, B,
It descends in the order of C and D. Here, the point between the point A and the point B is inclined because the semi-molten slag 6 is mixed in the upper layer of the molten slag 5. The reason why the points C and D are inclined is that the lower layer of the molten slag 5
Is mixed. According to FIG. 3, points B and C
According to the present invention, the temperature distribution of the molten slag 5 at the point B and the point C can be obtained with high accuracy even when the temperature distribution during the period does not change much. .

FIG. 4 shows that the temperature of the molten slag in the furnace is 1400 ° C.
9 is a graph showing the relationship between the probe feed amount and the impedance between electrodes 9 in the case of FIG. In FIG. 4, l _{0 to} l
₁ is the feed amount of the probe 8 until the electrode 9 reaches the molten slag 5 surface, and l _{1 to} l ₂ are the feed amount of the probe 8 until the electrode 9 reaches the molten slag 5 surface. ,
l _{2 to} l ₃ indicate the feed amount of the probe 8 until the electrode 9 reaches the furnace bottom from the surface of the molten metal 4.

Therefore, if the encoder 15 is reset with the time point of the change in the impedance between the electrodes 9 (A in FIG. 3) as the surface of the molten slag 5, the impedance calculating means 14 outputs the molten slag 5 in the furnace depth direction. The impedance between the electrodes 9 is obtained. This result is sent to the in-furnace molten slag temperature calculating means 16. Since the relationship between the molten slag temperature and the impedance between the electrodes 9 is stored in advance in the in-furnace molten slag temperature calculating means 16, the in-furnace depth direction in the furnace is determined by the impedance between the electrodes 9 calculated by the impedance calculating means 14. The temperature distribution of the molten slag is calculated. This result is displayed on the display unit 17.

During the calculation of the impedance between the electrodes 9,
It is necessary to temporarily stop energizing the incineration ash melting electrode 2. This is because when the voltage value and the current value between the detection electrodes are measured without stopping the current supply to the incineration ash melting electrode 2 to calculate the impedance, the electrode 2 generated when the molten slag is resistance-heated is measured. This is because the distributed voltage of the power supply causes noise in the voltage value and the current value between the electrodes for detection, and it is not possible to calculate an accurate impedance between the electrodes 9.
In addition, even if the output of the power supply for the electrode 2 is stopped for a short time, the heat capacity of the molten slag is large, so there is almost no decrease in the temperature of the molten slag and the convection of the molten slag is stopped. In one measurement, the stop time of the power supply output for the electrode 2 is preferably within 0.01 to 1 second.

[0019]

As described above, according to the present invention, a probe having a pair of detection electrodes attached to its tip is placed in a molten slag in a furnace while a voltage is applied between the detection electrodes. By inserting and measuring the impedance between the detection electrodes, the impedance between the detection electrodes changes depending on the temperature of the molten slag, so the relationship between the temperature of the molten slag and the impedance between the detection electrodes is determined in advance. If this is done, it is not necessary to use an expensive thermocouple, and a useful effect such that the temperature distribution in the furnace depth direction can be accurately measured with one probe is provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a method for measuring an in-furnace temperature of an incineration ash melting furnace according to the present invention.

FIG. 2 is a perspective view of a probe used in the present invention.

FIG. 3 is a graph showing a relationship between an electrode voltage and an electrode current and a probe feed amount.

FIG. 4 is a graph showing a relationship between an inter-electrode impedance and a probe feed amount.

FIG. 5 is a graph showing a relationship between impedance between electrodes and molten slag temperature.

[Explanation of symbols]

 1: incineration ash melting furnace, 2: incineration ash melting electrode, 3: electrode 2 power supply, 4: molten metal, 5: molten slag, 6: semi-molten slag, 7: probe, 8: coating material, 9: detection Electrodes for use, 10: feeder, 11: power supply for detection, 12: voltmeter, 13: ammeter, 14: impedance calculation means, 15: encoder, 16: molten slag temperature calculation means, 17: display means.

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Claims (1)

(57) [Claims] 1. A method for measuring a temperature in a furnace of an incineration ash melting furnace in which incineration ash charged in the furnace is melted by electric resistance heating by an incineration ash melting electrode inserted into the furnace. In the melting furnace, while lowering the probe having a pair of detection electrodes attached to the tip, the power supply to the incineration ash melting electrode is intermittently stopped for a short time, and during this time, the detection electrode Measuring the impedance of the molten slag in the furnace depth direction, based on the relationship between the molten slag temperature in the furnace and the impedance between the detection electrodes, which has been determined in advance. Characteristic method of measuring the temperature inside the incineration ash melting furnace.