JP2002171763A - Dc power supply unit for electric resistance type ash- melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously and steplessly regulate an output voltage and downsize the whole unit. SOLUTION: The primary side of a polyphase transformer 17 capable of steplessly changing the transformation ratio of the output voltage is connected to an AC power supply 16. A circuit 18 for a main electrode 3 of an ash-melting furnace connected to the main electrode 3 and a furnace bottom electrode 4 of the ash-melting furnace is provided on the secondary side of the polyphase transformer 17. A silicon rectifier 19 of a constant voltage and a thyristor rectifier 20 of a variable voltage are incorporated in series on the way of the circuit 18 for the main electrode 3. The thyristor rectifier 20 is subjected to a phase control to regulate the output voltage supplied to the main electrode 3 in response to a change in the load resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC power supply for an electric resistance type ash melting furnace which melts ash such as incineration ash and fly ash of waste.

[0002]

2. Description of the Related Art As shown schematically in FIG. 5, an electric resistance type ash melting furnace used for melting incineration ash and the like of wastes has a main electrode 3 at a central portion of a furnace lid 2. Is penetrated so as to be able to ascend and descend so that the lower end is inserted into the molten slag 6 on the molten metal layer 5 in the furnace body 1, so that the main electrode 3 and the furnace bottom electrode 4 provided on the bottom of the furnace body 1 are connected to each other. In between, DC power supply 7
Current based on the output voltage controlled by the melting slag 6
The ash 8 charged into the furnace body 1 is sequentially melted by Joule heat.

In the above-mentioned ash melting furnace, the load resistance between the electrodes 3 and 4 accompanying a change in the insertion amount of the main electrode 3 into the molten slag 6 and the thickness of the molten metal layer 5 becomes wide. In the power supply device 7, it is necessary to output a wide voltage according to the load resistance.

[0004] Therefore, the conventional DC power supply 7 has a configuration shown in FIG.
As shown in FIG. 1, a plurality (three in the figure) of taps 9a,
The primary side of the rectifier transformer 10 which can change the transformation ratio of the output voltage by the switching operation of 9b and 9c is connected to an AC power supply circuit, and the secondary side of the rectifier transformer 10 is The tap 9 is connected to the main electrode 3 and the bottom electrode 4 and has thyristor rectifiers 12a, 12b and 12c, respectively.
The configuration is such that a load-side circuit 11 having rectifier circuit units 13a, 13b, and 13c arranged in parallel and connected to a, 9b, and 9c, respectively, is connected. Reference numeral 14 denotes a DC reactor.

[0005]

However, in the case of the DC power supply 7, it is necessary to switch the taps 9a, 9b and 9c in order to change the output voltage. Therefore, it is not possible to continuously adjust the voltage steplessly, which is disadvantageous in terms of stable operation. In addition, as a countermeasure against harmonics to reduce the harmonic current to the power supply, 24 pulses Alternatively, a 12-pulse circuit 11 is used, but since there are rectifier circuits for the number of taps, a large space is required and there is a problem that the whole becomes large.

A bipolar electric resistance ash melting furnace in which a slag electrode is provided in the furnace body 1 separately from the main electrode 3 so as to be movable up and down so that molten slag is continuously slag. Aside from the DC power supply 7, a similar DC power supply is provided for the slag electrode, and the main electrode and the slag electrode are each provided with a rectifier independently, so that the entire device becomes larger. There was a problem with the installation space.

Therefore, the present invention enables the output voltage to the electrodes to be continuously and continuously adjusted in accordance with the fluctuation of the load resistance, and to reduce the size of the entire device. What you want to do.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for supplying an electric current between a main electrode which can be moved up and down in a furnace and a furnace bottom electrode which is installed at the bottom of the furnace. Thus, in a DC power supply device used in an electric resistance type ash melting furnace that is configured to melt ash charged in the furnace body,
The primary side of the polyphase transformer is connected to the AC power supply, and the secondary side of the polyphase transformer is provided with a main electrode circuit connected to the main electrode and the furnace bottom electrode. The configuration is such that a silicon rectifier and a thyristor rectifier are incorporated in series.

Since the silicon rectifier and the thyristor rectifier are connected in series, the output voltage to the main electrode is the sum of the output voltages of both rectifiers. At this time, the output voltage of the thyristor rectifier is made variable by phase control. Therefore, the output voltage can be continuously and continuously adjusted according to the change in the load resistance. Since the multi-phase transformer does not require a tap switching operation, the circuit can be simplified and the whole can be downsized.

Further, a first furnace chamber and a second furnace chamber which are communicated with each other at a lower portion in the furnace body are formed in a partitioned manner, and a main electrode arranged so as to be able to move up and down in the first furnace chamber and a furnace installed at the bottom of the furnace body. By supplying current between the bottom electrode and between the slag electrode and the furnace bottom electrode, which can be moved up and down in the second furnace chamber, the ash charged into the first furnace chamber is removed from the first furnace chamber. And a DC power supply used in an electric resistance type ash melting furnace that is melted in the second furnace chamber and discharged from the second furnace chamber, wherein the primary side of the multi-phase transformer is connected to an AC power supply, and On the secondary side of the polyphase transformer, a main electrode circuit connected to the main electrode and the furnace bottom electrode is provided, and the silicon rectifier and the thyristor rectifier are provided on the main electrode circuit, and the silicon rectifier is provided on the upstream side in the energization direction. So that it is connected in series with the upstream part of the silicon rectifier of the main electrode circuit. A circuit for the slag electrode connected to the slag electrode and the furnace bottom electrode is connected in parallel with the flow portion, a thyristor rectifier is incorporated in the slag electrode circuit, and the main electrode is connected to the slag electrode circuit. In this configuration, the output voltage to the main electrode and the output voltage to the slag electrode can be continuously adjusted by controlling the phase of the thyristor rectifier. Since the rectifier is shared, the size can be reduced as compared with the case where the silicon rectifier is used separately.

Further, by providing a total output limiter for limiting the total maximum output of the main electrode and the slag electrode, the capacity on the power supply side and the capacity of the polyphase transformer can be reduced. it can.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In an electric resistance type ash melting furnace having a configuration similar to that shown in FIG. 5, a DC power supply in which an output voltage is adjusted by a tap switching operation. Instead of the device 7, there is provided a DC power supply device 15A capable of continuously outputting a wide range of voltage according to the load resistance.

The DC power supply 15A includes an AC power supply 16
To the primary side of the multi-phase transformer 17,
7 is provided with a main electrode circuit 18 connected to the main electrode 3 as a load and the furnace bottom electrode 4, and a forward conversion type silicon rectifier 19 and a forward conversion / The reverse conversion type thyristor rectifier 20 and the silicon rectifier 19
Is installed in series so that is on the upstream side in the energization direction.
A DC reactor 1 is provided downstream of the thyristor rectifier 20.
4 is assembled.

In the DC power supply 15A for an electric resistance type ash melting furnace having the above-described configuration, the silicon rectifier 19 and the thyristor rectifier 20 are connected in series, so that the output voltage supplied to the main electrode 3 as a load is silicon. Rectifier 19
And the output voltage Et of the thyristor rectifier 20
And the sum of At this time, since the silicon rectifier 19 has no output adjustment element, the output voltage Es is constant, but the thyristor rectifier 20 can make the output voltage Et variable by phase control. , 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 is
It can be continuously adjusted over a wide range and steplessly according to the load resistance between the electrodes 3 and 4.

In the above description, the output voltage Es +
When adjusting Et, it is not necessary to perform a tap switching operation in a no-load state as in the related art, so that a stable operation can be performed with respect to a change in the load resistance between the electrodes 3 and 4.
In addition, since there is no need for a rectifier circuit section connected to the tap by eliminating the tap switching operation, the number of thyristor elements can be greatly reduced as compared with the conventional case, and the circuit configuration is simplified, so that the entire device The size can be reduced.

FIGS. 2 and 3 show another embodiment of the present invention, in which a DC power supply capable of stepless adjustment is applied to a bipolar electric resistance type ash melting furnace. That is, the inside of the furnace body 1 of the electric resistance type ash melting furnace having the same configuration as that shown in FIG. 5 is partitioned by a partition wall 21 extending downward from an upper end position to a required depth position.
A first furnace chamber 1a and a second furnace chamber 1b communicating with each other at the lower part of the furnace are defined, and the main electrode 3 and the second furnace chamber 1 are formed in the first furnace chamber 1a.
b, the slag electrode 22 is arranged so as to be able to move up and down, and the ash 8 can be put into the first furnace chamber 1a.
a into the second furnace chamber 1b through the lower part of the partition wall 21 and the second furnace chamber 1b.
In a bipolar electric resistance type ash melting furnace in which the molten slag 6 inside is overflowed from a slag port 23 provided on the side wall of the second furnace chamber 1b to continuously slag, a wide range according to the load resistance is obtained. DC power supply 15B capable of continuously and continuously outputting a voltage to main electrode 3 and slag electrode 22
Is provided.

As shown in FIG. 3, the DC power supply 15B has a configuration similar to that of the DC power supply 15A shown in FIG. 1, and is provided at a position sandwiching the silicon rectifier 19 of the main electrode circuit 18 between the upstream part and the downstream part. , A slag electrode circuit 24 connected to the slag electrode 22 and the furnace bottom electrode 4 are connected in parallel, and the slag electrode circuit 24 is connected to the forward / reverse conversion type thyristor rectifier 2.
5 and the DC reactor 14 are incorporated, and the silicon rectifier 19 of the main electrode circuit 18 is shared with the slag electrode circuit 24. Other configurations are the same as those shown in FIG. 1, and the same portions are denoted by the same reference numerals.

In the case of the DC power supply 15B shown in FIG. 3, the variation of the load resistance between the main electrode 3 and the furnace bottom electrode 4 is changed in series similarly to the case of the DC power supply 15A shown in FIG. Using the connected silicon rectifier 19 and thyristor rectifier 20, a current flows in the order of silicon rectifier 19-thyristor rectifier 20-DC reactor 14-main electrode 3, bottom electrode 4-silicon rectifier 19. By controlling the phase, the output voltage supplied to the main electrode 3 is adjusted.
2. With respect to the load variation between the furnace bottom electrodes 4, the silicon rectifier 19 and the thyristor rectifier 25 are connected in series using the silicon rectifier 19 and the thyristor rectifier 25.
An electric current flows in the order of the DC reactor 14-the slag electrode 22, the furnace bottom electrode 4-the silicon rectifier 19, and the output voltage supplied to the slag electrode 22 is adjusted by controlling the phase of the thyristor rectifier 25.

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 slag electrode 22 is Since it is the sum of the constant voltage and the variable voltage by the phase control of the thyristor rectifier 25, for example, the voltage of the main electrode 3 and the slag electrode 22 is set to 0 to 240 V
If the voltage of the silicon rectifier 19 is kept constant at 120 V, the thyristor rectifier 2
In the case of 0 and 25, both can be made variable in the range of -120V to + 120V, and the electrodes 3 and 22 as each load can be separately and widely controlled to 0 to 240V.
As described above, since the constant voltage silicon rectifier 19 is shared by the main electrode circuit 18 and the slag electrode circuit 24, the entire circuit 18 and 24 use an overall silicon rectifier as compared with the case where a silicon rectifier is used separately. Can be reduced in size, which is also advantageous in terms of cost.

FIG. 4 shows still another embodiment of the present invention. In the bipolar electric resistance type ash melting furnace DC power supply 15B shown in FIG. 3, the main electrode 3 and the slag electrode are used. A maximum output limiter 26 for limiting the total maximum output to the main electrode 3 is provided, and the output to the main electrode 3 is prioritized within the range of the set output value of the maximum output limiter 26, and the slag electrode 22
A rectifier controller 27 that sends a control command to the thyristor rectifier 20 of the main electrode circuit 18 so as to limit the output to the rectifier controller 27;
A rectifier controller 28 for sending a control command to a thyristor rectifier 25 of the slag electrode circuit 24.
5C. Other configurations are the same as those shown in FIG. 3, and the same portions are denoted by the same reference numerals.

In the case of the DC power supply 15C shown in FIG. 4, for example, when the maximum output of the main electrode 3 is set to 2000 kW and the maximum output of the slag electrode 22 is set to 1200 kW, the maximum output is set. The limiter 26 sets the total maximum output to 2000 kW. For example, when the output to the main electrode 3 needs to be 1600 kW, the output to the slag electrode 22 is limited to 400 kW, and the total output is suppressed to 2000 kW. To be able to

As described above, by limiting the total maximum output, the capacity on the power supply side can be reduced.
The contract power as demand equipment can be reduced, and accordingly, the operating cost of the facility, the capacity of the power factor improving capacitor on the power supply side can be reduced, and the capacity of the polyphase transformer 17 for the rectifier can also be reduced. Since it can be lowered, the size of the entire apparatus can be further reduced, which is more advantageous in terms of installation space.

[0024]

As described above, according to the DC power supply device for an electric resistance type ash melting furnace of the present invention, the main electrode arranged up and down in the furnace body and the furnace bottom electrode installed at the bottom of the furnace body are connected. In a DC power supply used in an electric resistance type ash melting furnace which is configured to melt ash put into the furnace body by flowing a current between the furnace, a primary side of a polyphase transformer is connected to an AC power supply, and On the secondary side of the polyphase transformer, a main electrode circuit connected to the main electrode and the furnace bottom electrode is provided, and the main electrode circuit is
Since the silicon rectifier and the thyristor rectifier are built in series, the output voltage to the main electrode can be continuously and continuously adjusted according to the fluctuation of the load resistance by controlling the phase of the thyristor rectifier. Operation can be performed, and the tap switching operation as in the related art is not required, so that the circuit can be simplified, the size of the entire apparatus can be reduced, and the lower body communicates with the furnace body. A first furnace chamber and a second furnace chamber are defined and formed between a main electrode arranged so as to be able to ascend and descend in the first furnace chamber and a furnace bottom electrode installed at the bottom of the furnace body, and ascendable and descendable into the second furnace chamber. By flowing a current between the disposed slag electrode and the furnace bottom electrode, 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. Used in electric resistance ash melting furnaces that are made to slag In the power supply apparatus, a primary electrode circuit connected to the main electrode and the bottom electrode is provided on the secondary side of the polyphase transformer, with the primary side connected to the AC power supply. A silicon rectifier and a thyristor rectifier are incorporated in the electrode circuit in series such that the silicon rectifier is located on the upstream side in the direction of current flow. The slag electrode circuit and the slag electrode circuit connected to the furnace bottom electrode are connected in parallel, a thyristor rectifier is incorporated in the slag electrode circuit, and the silicon rectifier of the main electrode circuit is shared with the slag electrode circuit. With such a configuration, the output voltage to the main electrode and the output voltage to the slag electrode can be respectively adjusted steplessly, and the common use of the silicon rectifier reduces costs and reduces the size of the entire device. Plan Door can be, further,
By providing a maximum output limiter for limiting the total maximum output of the main electrode and the slag electrode, the capacity on the power supply side can be reduced, the size can be reduced, and the multi-phase transformer can be achieved. , The capacity of the device can be reduced and the installation space can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a DC power supply for an electric resistance type ash melting furnace according to an embodiment of the present invention.

FIG. 2 shows another embodiment of the present invention, and is a schematic view showing an example of application to a bipolar electric resistance ash melting furnace.

FIG. 3 is a circuit diagram of the bipolar electric resistance type ash melting furnace DC power supply device shown in FIG. 2;

FIG. 4 is a circuit diagram of a DC power supply device for a bipolar electric resistance type ash melting furnace showing still 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 body 1a 1st furnace room 1b 2nd furnace room 3 Main electrode 4 Furnace bottom electrode 8 Gray 15A, 15B, 15C DC power supply 16 AC power supply 17 Polyphase transformer 18 Main electrode circuit 19 Silicon rectifier 20 Thyristor rectifier 22 Slag electrode 24 Slag electrode circuit 25 Thyristor rectifier 26 Maximum output limiter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Onoda 3-2-16-1 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center (72) Inventor Jun Hiraoka 3 Nishi-Awaji, Higashiyodogawa-ku, Osaka-shi, Osaka No. 1-56, Sansha Electric Manufacturing Co., Ltd. (72) Inventor Kazunori Doi 3-1-1, Nishiawaji, Higashi-Yodogawa-ku, Osaka-shi, Osaka F-term (reference) 3K058 AA00 AA95 BA19 CB06 CD01 GA08 3K061 NB01 4K063 AA04 AA12 BA13 CA04 CA07 FA22 FA23 FA25 5H006 AA06 CA03 CA07 CA12 CA13 CB02 CC02 DA04 DB02 DC05

Claims (3)

[Claims] 1. An electric current is applied between a main electrode which can be moved up and down in a furnace body and a furnace bottom electrode which is provided at the bottom of the furnace body so that the ash put into the furnace body is melted. In the DC power supply used for the electric resistance type ash melting furnace,
The primary side of the polyphase transformer is connected to the AC power supply, and the secondary side of the polyphase transformer is provided with a main electrode circuit connected to the main electrode and the furnace bottom electrode. A DC power supply for an electric resistance type ash melting furnace, having a configuration in which a silicon rectifier and a thyristor rectifier are incorporated in series. 2. A first device which communicates with a furnace body at a lower portion.
A furnace chamber and a second furnace chamber were defined and partitioned between a main electrode arranged to be able to move up and down in the first furnace chamber and a furnace bottom electrode installed at the bottom of the furnace body, and to be able to move up and down in the second furnace chamber. By supplying an electric current between the slag electrode and the furnace bottom electrode, the ash charged into the first furnace chamber is melted in the first furnace chamber and the second furnace chamber, and the ash is discharged from the second furnace chamber. In the DC power supply device used in the electric resistance type ash melting furnace, the primary side of the polyphase transformer is connected to the AC power source, and the main electrode and the bottom electrode are connected to the secondary side of the polyphase transformer. And a silicon rectifier and a thyristor rectifier are incorporated in the main electrode circuit in series such that the silicon rectifier is on the upstream side in the direction of current flow. Electrode connected to the slag electrode and the furnace bottom electrode between the upstream and downstream parts of An electric resistance, wherein a circuit is connected in parallel, a thyristor rectifier is incorporated in the slag electrode circuit, and the silicon rectifier of the main electrode circuit is shared with the slag electrode circuit. DC power supply for ash melting furnace. 3. A DC power supply for an electric resistance type ash melting furnace according to claim 2, further comprising a maximum output limiter for limiting the total maximum output of the main electrode and the slag electrode.