JP4564648B2 - DC power supply for electric resistance ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a direct current power supply device for an electric resistance type ash melting furnace in which ash such as incineration ash and fly ash of waste is melted.
[0002]
[Prior art]
An electric resistance type ash melting furnace used for melting incineration ash etc. of waste penetrates the main electrode 3 in the center of the furnace lid 2 so that it can be moved up and down as schematically shown in FIG. The lower end is inserted into the molten slag 6 on the molten metal layer 5 in the furnace body 1, and a direct current power source is provided between the main electrode 3 and the furnace bottom electrode 4 provided at the bottom of the furnace body 1. By passing a current based on the output voltage controlled by the device 7 through the molten slag 6, the ash 8 charged into the furnace body 1 is sequentially melted by Joule heat.
[0003]
In the ash melting furnace, since the load resistance between the electrodes 3 and 4 due to changes in the amount of insertion of the main electrode 3 into the molten slag 6 and the thickness of the molten metal layer 5 becomes wide, the DC power supply 7 Then, it is necessary to output a wide range of voltages according to the load resistance.
[0004]
For this reason, the conventional DC power supply device 7 can change the transformation ratio of the output voltage by switching the plurality of (three in the figure) taps 9a, 9b, 9c, as shown in FIG. The primary side of the rectifier transformer 10 is connected to an AC power supply circuit, and the secondary side of the rectifier transformer 10 is connected to the main electrode 3 and the furnace bottom electrode 4 and thyristor rectifiers 12a, 12b, and 12c are respectively connected. The load side circuit 11 having rectifier circuit portions 13a, 13b, and 13c arranged in parallel and connected to the taps 9a, 9b, and 9c, respectively, is connected. Reference numeral 14 denotes a DC reactor.
[0005]
[Problems to be solved by the invention]
However, in the case of the DC power supply device 7, in order to change the output voltage, it is necessary to switch the taps 9a, 9b, 9c. Voltage adjustment cannot be performed automatically, which is disadvantageous in terms of stable operation, and the circuit 11 of 24 pulses or 12 pulses is used as a harmonic countermeasure for reducing the harmonic current to the power supply side. However, since there are rectifier circuit portions corresponding to the number of taps, a large space is required, and there is a problem that the overall size is increased.
[0006]
Incidentally, in the bipolar electric resistance ash melting furnace in which the output electrode is provided in the furnace body 1 separately from the main electrode 3 so as to be movable up and down, and the molten slag is continuously output, Apart from the power supply device 7, a similar DC power supply device is provided for the output electrode, and the rectifier is provided for each of the main electrode and the output electrode. There was a problem above.
[0007]
Therefore, the present invention makes it possible to continuously adjust the output voltage to the electrode in a stepless manner in accordance with the variation of the load resistance, and to reduce the size of the entire apparatus. Is.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention has a first furnace chamber and a second furnace chamber which are communicated with each other in the lower part of the furnace body, and a main electrode and a furnace which are arranged to be movable up and down in the first furnace chamber. It is thrown into the first furnace chamber by flowing current between the furnace bottom electrode installed at the bottom of the body and between the tapping electrode arranged in the second furnace chamber so as to be able to move up and down and the furnace bottom electrode. In a DC power supply device used in an electric resistance ash melting furnace in which the ash is melted in the first furnace chamber and the second furnace chamber and discharged from the second furnace chamber , the primary phase of the multiphase transformer is used as the AC power source. A main electrode circuit connected to the main electrode and the furnace bottom electrode is provided on the secondary side of the multiphase transformer, and a silicon rectifier and a thyristor rectifier are connected to the main electrode circuit with silicon. The rectifier is installed in series so that it is on the upstream side of the energizing direction. An output electrode circuit connected to the output electrode and the furnace bottom electrode is connected in parallel between the upstream portion and the downstream portion of the output rectifier, and a thyristor rectifier is incorporated in the output electrode circuit. The main circuit is configured to share the silicon rectifier of the main electrode circuit .
[0009]
Since the silicon rectifier and the thyristor rectifier are connected in series in the main electrode circuit and the output electrode circuit, the output voltage to the main electrode and the output voltage to the output electrode are the output voltage of both rectifiers for each circuit . In this case, since the output voltage of the thyristor rectifier can be made variable by phase control, the output voltage can be continuously adjusted steplessly in accordance with the variation of the load resistance. Since the polyphase transformer does not require a tap switching operation, the circuit can be simplified and the whole can be miniaturized.
[0010]
Further, divorced rectifier since there as a shared main electrode circuit and the tapping electrode circuit can be miniaturized as compared with the case of using silicon rectifier separately.
[0011]
Furthermore, by providing a total output limiter for limiting the total maximum output of the main electrode and the output electrode, it is possible to reduce the power supply side capacity and the capacity of the multiphase transformer.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows an embodiment of a DC power supply device for an electric resistance type ash melting furnace. In an electric resistance type ash melting furnace having the same configuration as shown in FIG. 5, the output voltage is adjusted by a tap switching operation. Instead of the direct current power supply device 7, a direct current power supply device 15 </ b> A that can output a wide range of voltages according to the load resistance in a stepless manner is provided.
[0014]
The DC power supply device 15 </ b> A is connected to the AC power supply 16 on the primary side of the multiphase transformer 17, and on the secondary side of the multiphase transformer 17 is connected to the main electrode 3 and the furnace bottom electrode 4 as a load. The main electrode circuit 18 is provided, and a forward conversion type silicon rectifier 19 and a forward conversion / reverse conversion type thyristor rectifier 20 are provided in the main electrode circuit 18 so that the silicon rectifier 19 is upstream in the energization direction. And a DC reactor 14 is assembled on the downstream side of the thyristor rectifier 20.
[0015]
Since the silicon rectifier 19 and the thyristor rectifier 20 are connected in series in the electric resistance type ash melting furnace DC power supply device 15A having the above-described configuration, the output voltage supplied to the main electrode 3 as a load is that of the silicon rectifier 19. This is the sum of the output voltage Es and the output voltage Et of the thyristor rectifier 20. At this time, since the silicon rectifier 19 has no output adjusting element, the output voltage Es is constant. However, since the thyristor rectifier 20 can change the output voltage Et by phase control, the output voltage Et of the thyristor rectifier 20 is variable. By controlling the phase, the value of the output voltage Es + Et supplied to the main electrode 3 can be changed. Therefore, the output voltage Es + Et supplied to the main electrode 3 can be continuously adjusted in a wide range and steplessly according to the load resistance between the electrodes 3 and 4.
[0016]
In the above, when adjusting the output voltage Es + Et to the main electrode 3, it is not necessary to perform the tap switching operation in a no-load state as in the prior art. In addition, since the rectifier circuit section connected to the tap is eliminated by eliminating the tap switching operation, the number of thyristor elements can be greatly reduced as compared with the prior art, and the circuit configuration is simplified. Therefore, the entire apparatus can be reduced in size.
[0017]
Next, FIGS. 2 and 3 show one embodiment of the present invention, is obtained by applying the stepless adjustable DC power supply to the electrical resistance type ash melting furnace bipolar. That is, the inside of the furnace body 1 of the electric resistance type ash melting furnace having the same configuration as shown in FIG. 5 is partitioned by the partition wall 21 extending downward from the upper end position to the required depth position, and below the partition wall 21. The first furnace chamber 1a and the second furnace chamber 1b that communicate with each other are partitioned, and the main electrode 3 is disposed in the first furnace chamber 1a and the output electrode 22 is disposed in the second furnace chamber 1b so as to be movable up and down. In addition, the ash 8 can be charged into the first furnace chamber 1a so that the molten slag 6 in the first furnace chamber 1a flows into the second furnace chamber 1b through the lower part of the partition wall 21, and the second In a bipolar electric resistance ash melting furnace in which the molten slag 6 in the furnace chamber 1b overflows from a tap outlet 23 provided on the side wall of the second furnace chamber 1b and is continuously discharged, according to the load resistance. A wide range of voltages are continuously applied to the main electrode 3 and the output electrode 22 in a stepless manner. It is provided with a DC power supply device 15B that allow the force.
[0018]
As shown in FIG. 3, the DC power supply device 15B has a configuration similar to that of the DC power supply device 15A shown in FIG. 1, and is connected to a position where the silicon rectifier 19 of the main electrode circuit 18 is sandwiched between the upstream portion and the downstream portion. An output electrode circuit 24 connected to the electrode 22 and the furnace bottom electrode 4 is connected in parallel. A forward / reverse conversion type thyristor rectifier 25 and a DC reactor 14 are incorporated in the output electrode circuit 24, and the output In this configuration, the silicon rectifier 19 of the main electrode circuit 18 is shared by the saddle electrode circuit 24. Other configurations are the same as those shown in FIG. 1, and the same parts are denoted by the same reference numerals.
[0019]
In the case of the DC power supply device 15B shown in FIG. 3, the variation in load resistance between the main electrode 3 and the furnace bottom electrode 4 is connected in series as in the case of the DC power supply device 15A shown in FIG. The silicon rectifier 19 and the thyristor rectifier 20 are used to pass a current in the order of the silicon rectifier 19, the thyristor rectifier 20, the DC reactor 14, the main electrode 3, the furnace bottom electrode 4, and the silicon rectifier 19, and the phase control of the thyristor rectifier 20. The output voltage supplied to the main electrode 3 is adjusted by performing the steps described above, while the silicon rectifier 19 and the thyristor rectifier connected in series with respect to the load fluctuation between the output electrode 22 and the furnace bottom electrode 4 are adjusted. 25, current is passed in the order of silicon rectifier 19-thyristor rectifier 25-DC reactor 14-output electrode 22, furnace bottom electrode 4-silicon rectifier 19 in this order. So as to adjust the output voltage to be supplied to the tapping electrode 22 by performing the phase control of the thyristor rectifier 25.
[0020]
The output voltage to the main electrode 3 is the sum of the constant voltage of the silicon rectifier 19 and the variable voltage by the phase control of the thyristor rectifier 20, and the output voltage to the output electrode 22 is the same as the constant voltage of the silicon rectifier 19. Since this is the sum of the variable voltages by the phase control of the thyristor rectifier 25, for example, when the voltage of the main electrode 3 and the output electrode 22 can be adjusted to 0 to 240V, the voltage of the silicon rectifier 19 is fixed to 120V. In the thyristor rectifiers 20 and 25, both can be made variable in the range of −120V to + 120V, and the electrodes 3 and 22 as the respective loads can be separately controlled in a wide range from 0 to 240V. Thus, since the constant voltage silicon rectifier 19 is shared by the main electrode circuit 18 and the output electrode circuit 24, the entire circuit 18 and 24 is compared with the case where the silicon rectifier is used separately. Can be reduced in size, which is advantageous in terms of cost.
[0021]
Next, FIG. 4 shows another embodiment of the present invention. In the bipolar electric resistance type ash melting furnace DC power supply device 15B shown in FIG. 3, the total to the main electrode 3 and the output electrode 22 is shown. A maximum output limiter 26 is provided for limiting the maximum output of the output signal. The output to the main electrode 3 is prioritized within the range of the set output value of the maximum output limiter 26 to limit the output to the output electrode 22 And a rectifier controller 27 for sending a control command to the thyristor rectifier 20 of the main electrode circuit 18 and a rectifier controller 28 for sending a control command to the thyristor rectifier 25 of the output electrode circuit 24. It is what. Other configurations are the same as those shown in FIG. 3, and the same portions are denoted by the same reference numerals.
[0022]
In the case of the DC power supply device 15C shown in FIG. 4, for example, when the maximum output value to the main electrode 3 is set to 2000 kW and the maximum value to the output electrode 22 is set to 1200 kW, the maximum output limiter 26 is operated. The total maximum output is set to 2000 kW. For example, when the output to the main electrode 3 needs 1600 kW, the output to the output electrode 22 is limited to 400 kW so that the total can be suppressed to 2000 kW. To do.
[0023]
In this way, by limiting the total maximum output, the capacity on the power supply side can be reduced, and the contract power as a demand facility can be lowered. Since the capacity of the power factor improving capacitor can be reduced and the capacity of the rectifier multiphase transformer 17 can also be reduced, the entire apparatus can be further reduced in size, which is more advantageous in terms of installation space. It becomes.
[0024]
【The invention's effect】
As described above, according to the electric resistance type ash melting furnace DC power supply device of the present invention, the first furnace chamber and the second furnace chamber which are communicated with each other at the lower part in the furnace body are partitioned, and the first furnace chamber is formed. Current flows between the main electrode arranged on the bottom of the furnace and the bottom electrode installed on the bottom of the furnace body, and between the extraction electrode arranged on the second furnace chamber and the furnace bottom electrode. In the DC power supply apparatus used in the electric resistance ash melting furnace, the ash charged into the first furnace chamber is melted in the first furnace chamber and the second furnace chamber and discharged from the second furnace chamber. The primary side of the multiphase transformer is connected to the AC power source, and the main electrode circuit connected to the main electrode and the furnace bottom electrode is provided on the secondary side of the multiphase transformer. Incorporating a silicon rectifier and a thyristor rectifier in series so that the silicon rectifier is upstream in the energizing direction Further, an output electrode circuit connected to the output electrode and the furnace bottom electrode is connected in parallel between the upstream portion and the downstream portion of the silicon rectifier of the main electrode circuit, and the thyristor is connected to the output electrode circuit. incorporate rectifier, said output grounds since the electrode circuit are a structure which is adapted to share a silicon rectifier of the main electrode circuit, respectively stepless output voltage to the output voltage and the tapping electrode of the main electrodes In addition, the common use of the silicon rectifier can reduce the cost and reduce the overall size of the device, and the maximum output to limit the total maximum output of the main electrode and the output electrode. By having a configuration provided with a limiter, the capacity on the power supply side can be reduced and downsizing can be achieved, and the capacity of the multiphase transformer can also be reduced, and the installation space can be further reduced. Etc. It is effective.
[Brief description of the drawings]
1 is a circuit diagram showing one embodiment of the electrical resistance type ash melting furnace DC power supply.
FIG. 2 is a schematic diagram showing an embodiment of a DC power supply device for an electric resistance ash melting furnace according to the present invention, which is applied to a bipolar electric resistance ash melting furnace.
FIG. 3 is a circuit diagram of the bipolar electric resistance ash melting furnace DC power supply device shown in FIG. 2;
FIG. 4 is a circuit diagram of a DC electric power supply device for a bipolar electric resistance ash melting furnace showing another embodiment of the present invention.
FIG. 5 is a schematic view showing an example of an electric resistance type ash melting furnace.
FIG. 6 is a circuit diagram showing an example of a conventional DC power supply device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Furnace 1a 1st furnace chamber 1b 2nd furnace chamber 3 Main electrode 4 Furnace bottom electrode 8 Ash 15A, 15B, 15C DC power supply device 16 AC power supply 17 Multiphase transformer 18 Main electrode circuit 19 Silicon rectifier 20 Thyristor rectifier 22 Output electrode 24 Output electrode circuit 25 Thyristor rectifier 26 Maximum output limiter

Claims (2)

  A first furnace chamber and a second furnace chamber that communicate with each other in the lower part of the furnace body are partitioned and formed between a main electrode disposed in the first furnace chamber so as to be movable up and down and a furnace bottom electrode disposed at the bottom of the furnace body. The ash charged into the first furnace chamber is made to flow into the first furnace chamber and the second furnace chamber by flowing current between the tapping electrode disposed in the second furnace chamber so as to be movable up and down, and the furnace bottom electrode. In the direct current power supply apparatus used for the electric resistance ash melting furnace which is melted in the second furnace chamber and connected to the primary side of the multiphase transformer, A main electrode circuit connected to the main electrode and the furnace bottom electrode is provided on the secondary side, and a silicon rectifier and a thyristor rectifier are connected to the main electrode circuit in series so that the silicon rectifier is upstream in the energization direction. In addition, between the upstream portion and the downstream portion of the silicon rectifier of the main electrode circuit, The lead electrode circuit connected to the lead electrode and the furnace bottom electrode is connected in parallel, a thyristor rectifier is incorporated in the lead electrode circuit, and the silicon rectifier of the main electrode circuit is shared by the lead electrode circuit A DC power supply device for an electric resistance type ash melting furnace, characterized by having the configuration as described above. The main electrode and the tapping electrode of the total maximum output maximum output limiter electrical resistance type ash melting furnace DC power supply device according to claim 1, wherein provided for limiting.

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