JP4747927B2 - Method and apparatus for melting control of electric resistance ash melting furnace - Google Patents

Description

  The present invention relates to a melting control method and apparatus for an electric resistance ash melting furnace in which an electrode charged in the furnace is energized to melt ash, and more particularly to control during startup of an electric resistance ash melting furnace. Is.

  An example of an electric resistance type ash melting furnace for melting incineration ash such as municipal waste incineration ash is shown in FIG. As shown in FIG. 4, the electric resistance ash melting furnace includes a melting furnace 53, an incineration ash charging device 54, a power supply device 55, and a molten slag solidifying device 56. A slag outlet 59 that is opened and closed by a slag outlet gate 60 and a molten metal discharge port 61 (usually closed) are installed on the side wall of the furnace main body 57 that is the main component of the melting furnace 53. The device 54 includes a hopper 62, a cutting device 63, a chute 64, and an input amount setting device 65. The power supply device 55 includes a power calculator 66, a power controller 67, a power transformer 68, and electrodes 58a, 58b, and 58c. In this electric resistance ash melting furnace, an AC voltage is supplied to the three electrodes 58 a, 58 b, 58 c inserted from the upper part of the melting furnace 53, and the incinerated ash 50 and molten slag 51 charged by the charging device 54 are energized. It melts using heat generated by Joule heat during energization.

  The electric resistance ash melting furnace configured as described above is operated as follows. Based on the input amount set by the input amount setting device 65, a certain amount of incineration ash 50 is input into the furnace main body 57 per hour. The electric power calculator 66 calculates electric power according to the input amount of the incineration ash 50 and supplies electric power necessary for melting to the electrodes 58a, 58b, 58c. When melting progresses and the molten metal surface of the molten slag 51 in the furnace body 57 rises to a predetermined position, the slag outlet gate 60 is opened, and the molten slag 51 is discharged and solidified by the solidifying device 56. By repeating this, the incineration ash 50 is melted. During this operation, the power supply amount is set and adjusted so that a constant temperature is maintained by monitoring the temperature of the discharged molten slag 51, the furnace temperature of the furnace body 57, the cooling water temperature of the furnace body 57, or the like. Is done. By operating in this way, the molten slag 51 can be automatically controlled relatively easily to an appropriate temperature. When a predetermined amount or more of the molten metal 52 is accumulated in the furnace body 57, the molten metal discharge port 61 is opened and discharged.

Regarding the power control method of the three-phase AC power source of the above electric resistance type ash melting furnace, for example, the impedance and power of each electrode are measured, the impedance of each electrode is controlled by raising and lowering each electrode, and the overall power is There has been proposed a power control method in which the amount of input power is largely controlled while maintaining the balance of the current of each phase by controlling the tap of the furnace power transformer (see, for example, Patent Document 1).
Japanese Patent No. 3629988

  On the other hand, the refractory constituting the furnace body is a consumable item, and if the operation is performed for a certain period of time, all of the molten slag and molten metal in the furnace body are discharged, and inspection / repair in the furnace is required. In this case, after the furnace body is cooled to room temperature, inspection / repair work is performed, so it is necessary to bring it back up to the operation state. When starting up, lay a conductive substance such as carbon powder on top of the incineration ash so that the top of the electrode is tied, lower the electrode on it, put the incineration ash on it, energize the incineration ash Melt a part of. After that, the temperature and power value to be continuously operated are gradually increased while adjusting the electrode height and the amount of incinerated ash input.

  Since the power control method of the above-mentioned Patent Document 1 can perform power control in a state where the incineration ash is melted to some extent, automatic power control is performed during the period from the start-up until the incineration ash is melted to some extent. Is impossible, and manual operation by an operator is necessary. That is, until a part of the incinerated ash is melted to some extent at the time of start-up, the power control adjusts the input power by manual operation while constantly monitoring the change of the melting state in the furnace or the power, There is a problem that continuous monitoring is required and variation in input power occurs, making it impossible to perform optimal power control.

  The present invention has been made in order to solve the above-described problems, and it is possible to automatically control without requiring an operator's manual operation from the initial stage of the start-up of the electric resistance type ash melting furnace. It is an object of the present invention to provide a melting control method and apparatus for an electric resistance ash melting furnace that can be realized.

The melting control method of the electric resistance ash melting furnace according to the present invention is a melting control method of an electric resistance ash melting furnace in which the ash is melted by energizing an electrode charged in the furnace,
Setting the raising and lowering range of the electrode in a program manner;
Measuring the power supplied to the electrode;
A step of controlling the power supplied to the electrode by controlling the raising and lowering of the electrode and adjusting the applied voltage of the electrode according to a deviation between a target value of the power supplied to the electrode and an actual measured value of the measured power. And
In the power control, the control of raising / lowering the electrode within the raising / lowering range of the electrode is given priority over the adjustment of the applied voltage of the electrode.
Moreover, the melting control method of the electric resistance type ash melting furnace according to the present invention further includes a step of setting a target value of the power supplied to the electrode in a program type.

The electric resistance ash melting furnace melting control apparatus according to the present invention is an electric resistance ash melting furnace melting control apparatus that melts ash by energizing an electrode charged in the furnace,
An electrode lifting range setting means for setting the lifting range of the electrode in a program manner;
A wattmeter for measuring the power supplied to the electrode;
The power supplied to the electrode by controlling the raising and lowering of the electrode and adjusting the voltage applied to the electrode according to the deviation between the target value of the power supplied to the electrode and the actual measured value of the power measured by the wattmeter. In the power control, a power supply control means for giving priority to the control of the lifting / lowering of the electrode within the lifting / lowering range of the electrode over the adjustment of the applied voltage of the electrode is provided.
In addition, the melting control apparatus for an electric resistance type ash melting furnace according to the present invention further includes power setting means for setting a target value of power supplied to the electrodes in a program form.
Moreover, the melting control apparatus of the electric resistance type ash melting furnace which concerns on this invention sets the raising / lowering range of the said electrode so that it may expand with progress of operation time after an operation start.
In the present invention, setting the lifting range of the electrodes in a program manner means that the lifting range is changed with the elapsed time and is set (time schedule setting). When digital processing is performed by a microprocessor or the like It is assumed that not only analog processing but also cases are included. The same applies to the case where the power target value is set in a program form.

  In the present invention, the raising / lowering range of the electrode is set to a program type, and the raising / lowering control of the electrode and the voltage applied to the electrode are controlled according to the deviation between the target value of the power supplied to the electrode and the measured value of the measured power. The electric power supplied to the electrode is controlled by adjustment, and in the electric power control, the electrode elevation control within the electrode elevation range is given priority over the adjustment of the applied voltage of the electrode, for example, electric resistance ash melting If power control cannot be performed by raising / lowering the electrode during startup of the furnace (due to restrictions on the lifting / lowering range of the electrode), power control is performed by adjusting the applied voltage of the electrode. When the lifting range is expanded, the power control is automatically performed from the start of the start-up operation by performing the power control by raising and lowering the electrodes. For this reason, it is possible to automatically start up the furnace without requiring manual operation by an operator from the initial stage of starting up the furnace.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of an embodiment of the present invention, and is a schematic system diagram of an electric resistance ash melting furnace.

  As shown in FIG. 1, the furnace body 4 that melts the incineration ash 1 such as municipal waste incineration ash inside has an outer shell covered with an iron skin 28, and a refractory 29 is installed in the inside. The side wall of the furnace body 4 has a slag outlet 23 for discharging the molten slag 2 generated by melting the incinerated ash 1 and a molten metal discharge for discharging the molten metal 3 generated when the incinerated ash 1 is melted. The slag outlet 23 is opened and closed by a slag outlet gate 24, and the molten metal discharge port 25 is opened and closed by a molten metal hot water gate 26, respectively. And the upper opening part of the furnace main body 4 is covered with the furnace cover 5, The duct 27 connected with a dust collector (not shown) is installed in the furnace cover 5. As shown in FIG.

  Above the furnace body 4, a hopper 19 for storing the incineration ash 1 is installed inside, and the incineration ash 1 in the hopper 19 is cut out by a cutting device 21 installed at the lower part of the hopper 19, It is put into the furnace body 4 through a chute 22 that penetrates the furnace lid 5. The hopper 19 is supported by the load cell 20, and the weight of the hopper 19 including the incineration ash 1 is measured by the load cell 20, and this weight measurement value is an input amount control for controlling the input amount of the incineration ash 1 into the furnace body 4. It is transmitted to the board 18.

  The input amount control panel 18 is connected to an input amount program setting device 17 for setting the input amount of the incinerated ash 1 into the furnace body 4 in a program form. The input amount program setting unit 17 outputs the input amount target value at each elapsed time from the start of input to the input amount control panel 18 based on the time schedule of the input amount target value input in advance.

  The input amount control panel 18 compares the target value of the input amount for each elapsed time input from the input amount program setting unit 17 with the actual value of the input amount measured by the load cell 20 and responds to the deviation. Thus, the control output to the cutting device 21 is changed so that the deviation is reduced. Based on this command, the cutting device 21 adjusts the cutting amount to adjust the feeding amount.

  The furnace lid 5 is provided with three electrodes 6a, 6b and 6c passing through the furnace lid 5. The electrodes 6 a, 6 b, 6 c are respectively held by the electrode support arm 9, and the electrodes 6 a, 6 b, 6 c are moved up and down in the furnace body 4 by operating the electrode lifting / lowering device 10 connected to the electrode support arm 9. It is possible to make it. The electrode lifting / lowering device 10 raises / lowers the electrodes 6a, 6b, 6c by a control output from a power control panel 15 described later, thereby adjusting the power supplied to the electrodes 6a, 6b, 6c. In FIG. 1, an electrode support arm that holds the electrodes 6b and 6c and an electrode lifting device that is connected to these electrode support arms are omitted.

  The electrodes 6a, 6b, and 6c are connected to the power transformer 7, and the three-phase AC power is supplied from the power transformer 7. A primary voltage adjusting device 8 is installed on the primary side of the power transformer 7, and the primary side of the power transformer 7 is adjusted by the primary voltage adjusting device 8 to adjust the secondary side of the power transformer 7. Is adjusted, and the power supplied to the secondary-side electrodes 6a, 6b, 6c is adjusted.

  The electrodes 6a, 6b, and 6c are provided with an ammeter 11, a voltmeter 12, and a wattmeter 13, respectively. The current and voltage supplied to the electrodes 6a, 6b, and 6c by the ammeter 11 and the voltmeter 12 respectively. Each is measured. The measured current value and voltage value are input to the wattmeter 13, and the power supplied to each electrode 6a, 6b, 6c is measured. The total power measured by the electrodes 6 a, 6 b and 6 c is input to the power control panel 15. In FIG. 1, an ammeter, a voltmeter and a wattmeter for measuring the power supplied to the electrodes 6b and 6c are omitted.

  Connected to the power control panel 15 is a program setter 14 that outputs a target value of power supplied to the electrodes 6a, 6b, 6c to the power control panel 15. In the program setter 14, the power supplied to the electrode at each elapsed time from the start of energization is set in advance as a time schedule for the power target value. The power control panel 15 compares the target power value for each elapsed time input from the program setter 14 with the total power of the electrodes 6a, 6b, 6c measured by the wattmeter 13 and the deviation thereof. Accordingly, the control output to the primary voltage regulator 8 is changed so that the deviation is reduced. Based on this command, the primary voltage adjustment device 8 adjusts the primary voltage of the power transformer 7 to adjust the power supplied to the electrodes 6a, 6b, 6c. Further, the control output from the power control panel 15 is given to the electrode lifting / lowering device 10 to change the height of the electrodes 6a, 6b, 6c to control the supplied power.

  Since the incinerated ash is not melted for a certain period from the start of the start-up operation of the ash melting furnace, it is difficult to control the power by raising and lowering the electrodes. Therefore, the primary voltage regulator 8 adjusts the primary voltage of the power transformer 7. The power supplied to the electrode is adjusted. However, after the start-up operation is started, the incineration ash is gradually melted as time passes, and when the amount of molten slag increases, the range of raising and lowering of the electrode that can be operated for power control is gradually expanded. Corresponding to this phenomenon, the elevation range of the electrode at each elapsed time from the start of energization is preset in the program setting unit 14 as a time schedule for the electrode upper limit position and electrode lower limit position. Therefore, in the program setting unit 14 of the present embodiment, the time schedule of the power target value and the time schedule of the electrode lifting / lowering range are set in a program manner.

  In the present embodiment, the program setter 14 corresponds to the electrode elevation range setting means and the power setting means of the present invention, and the electrodes 6a, 6b, 6c, the ammeter 11, the voltmeter 12, the wattmeter 13, The primary voltage regulator 8, the hydraulic cylinder 10 and the power control panel 15 correspond to the supply power control means of the present invention.

A startup operation method in the electric resistance ash melting furnace having the above-described configuration will be described below.
First, before starting up, the time schedule of the target value of the electrode supply power is input to the program setting device 14 in advance, and the time schedule of the electrode elevation range is input in advance. A conductive material such as carbon powder is laid on the incinerated ash charged into the melting furnace so as to tie the vertices of the electrodes 6a, 6b, 6c, and the electrodes 6a, 6b, 6c are lowered thereon, and further thereon The incineration ash is applied and supplied to start energization of the electrodes 6a, 6b, 6c, and a part of the incineration ash is melted. As described above, the adjustment of the power supplied to the electrodes 6a, 6b, 6c is performed by using the power target value for each elapsed time preset by the program setter 14 and the actual measured value of power measured by the wattmeter 13. The primary voltage adjustment device 8 adjusts the primary voltage of the power transformer 7 by the control output from the power control panel 15 and the electrode lifting device 10 is connected to the electrodes 6a and 6b so that the deviation is reduced. , 6c is moved up and down to control power.

  When this power supply control is performed, the power control panel 15 is moved up and down within the limit range of electrode elevation for each elapsed time based on the time schedule of the electrode elevation range previously input to the program setter 14. Control output is issued to the primary voltage adjusting device 8 and the electrode lifting / lowering device 10.

  An example of the melting control method when starting up the electric resistance ash melting furnace will be described in detail with reference to FIG. FIG. 2 is an example of a flowchart of a power control method at startup.

  As shown in FIG. 2, the power target value is compared with the actual measured value of power measured by the wattmeter 13 (S11). If it is determined that the actual measured power value exceeds the target power value, the electrode position is then compared with the upper limit position (S12). Note that the power target value and the upper limit position described above indicate the power target value for each elapsed time and the upper limit position of the electrode set in advance by the program setter 14 and values at the start of startup. If it is determined that the electrode position is higher than the upper limit position, the primary voltage regulator 8 lowers the primary voltage of the power transformer 7 to reduce the power supplied to the electrode (S13, S14). . When it is determined that the electrode position is not more than the upper limit position, the position of the electrodes 6a, 6b, 6c is raised by the electrode lifting device 10 to reduce the power supplied to the electrodes 6a, 6b, 6c. (S15, S14).

  In the above determination (S11), if it is determined that the actual measurement value does not exceed the power target value, the electrode position and the lower limit position are compared (S16). Note that this lower limit position indicates a value at the start of the start of the lower limit positions for each elapsed time preset by the program setter 14. When it is determined that the electrode position is lower than the lower limit position, the primary voltage regulator 8 increases the primary voltage of the power transformer 7 to increase the power supplied to the electrode (S17, S18). . If it is determined that the electrode position is equal to or higher than the lower limit position, the positions of the electrodes 6a, 6b, 6c are lowered to increase the power supplied to the electrodes 6a, 6b, 6c (S19, S18). . After the above power reduction or power increase processing (S14, S18), the electrode elevation range (upper limit value / lower limit value) and the power target value are changed according to the setting for each elapsed time of the program setter 14. (S20) Unless there is an end command (S21), the process returns to the above process (S11) and a series of processes are repeated. By controlling the power supplied to the electrodes 6a, 6b, and 6c as described above, power control can be automatically performed from the start of the start-up operation.

  As described above, in the present embodiment, the time schedule of the lift range of the electrode that is input in advance so that the lift range of the electrode expands as time elapses after the start-up operation starts, and the power target value supplied to the electrode The power supplied to the electrode is controlled based on the time schedule of the electrode, and if the incineration ash has not melted for a certain amount of time from the start of start-up operation, and it is difficult to control the power by raising and lowering the electrode, the electrode The power is controlled by adjusting the voltage supplied to the power supply, and when the time has elapsed since the start of the start-up operation and the electrode lift range is expanded, the power control is performed by the electrode lift. Therefore, power control is possible. This eliminates the need for the operator to manually adjust the supply power while constantly monitoring changes in the melting state of the furnace or the power, which was necessary in the conventional startup operation. It is possible to solve the problem that power variation occurs and optimal power control cannot be performed.

  In addition, although said description demonstrated the electric resistance type ash melting furnace provided with the three electrodes 6a, 6b, 6c, this invention is not limited to this, The electric resistance type | formula provided with two or more electrodes The same can be applied to any ash melting furnace.

  An embodiment when the electric resistance ash melting furnace shown in FIG. 1 is started up by performing the processing of the flowchart of FIG. 2 will be described below.

  In this embodiment, the time schedule of the target value of the ash input amount is linearly increased to 200 kg / h in a time zone corresponding to, for example, a temperature rise from room temperature (25 ° C.) to 375 ° C. A constant value of 200 kg / h is set in the holding time zone, and the pattern is linearly increased from 200 kg / h to 400 kg / h in the time zone corresponding to the temperature rise from 375 ° C. to 600 ° C. The raising / lowering range of the electrode is set as a time schedule of the electrode upper limit position and the electrode lower limit position, and is set so that the range increases with the passage of time. Then, incineration ash having a thickness of about 150 mm was charged in advance into the furnace body, and energization was started.

  FIG. 3 is a diagram showing the transition of the supplied power, the ash input amount, and the electrode elevation range in this example. In FIG. 3, the straight line a is the target value of the supplied power, the curve b is the actually measured value of the supplied power, the straight line c is the target value of the incinerated ash input, the curve d is the actually measured amount of incinerated ash, and the straight line e is the electrode upper limit position. The straight line f is the electrode lower limit position. The actual value b of the supplied power and the actually measured value d of the amount of incinerated ash input in this start-up operation are as shown in FIG. 3, both of which are controlled according to the target value, and are automatically applied by applying the present invention. It was confirmed that the startup operation can be controlled.

It is a figure which shows one example of embodiment of this invention, and is a schematic systematic diagram of an electric resistance type ash melting furnace. It is a figure which shows one example of embodiment of this invention, and is an example of the flowchart of the furnace temperature control method. It is a figure which shows transition of the electric power supplied when this invention is applied, the amount of ash inputs, and the electrode raising / lowering range. It is a schematic system diagram of the conventional electric resistance type ash melting furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incinerated ash 2 Molten slag 3 Molten metal 4 Furnace 5 Furnace lid 6a, 6b, 6c Electrode 7 Power supply transformer 8 Primary voltage regulator 9 Electrode support arm 10 Electrode raising / lowering device 11 Ammeter 12 Voltmeter 13 Wattmeter 14 Program setting Device 15 Electric power control panel 16 Thermometer 17 Input amount program setting device 18 Input amount control panel 19 Hopper 20 Load cell 21 Cutting device 22 Chute 23 Slag outlet 24 Slag outlet gate 25 Molten metal outlet 26 Molten metal outlet gate 27 Duct 28 Iron skin 29 refractory

Claims (5)

A melting control method for an electric resistance ash melting furnace that melts ash by energizing an electrode charged in the furnace,
Setting the raising and lowering range of the electrode in a program manner;
Measuring the power supplied to the electrode;
A step of controlling the power supplied to the electrode by controlling the raising and lowering of the electrode and adjusting the applied voltage of the electrode according to a deviation between a target value of the power supplied to the electrode and an actual measured value of the measured power. And
In the electric power control, the control for raising and lowering the electrode within the raising and lowering range of the electrode is prioritized over the adjustment of the voltage applied to the electrode. The melting control method for an electric resistance ash melting furnace according to claim 1, further comprising a step of setting a target value of electric power supplied to the electrode in a program form. A melting control device for an electric resistance type ash melting furnace that melts ash by energizing an electrode charged in the furnace,
An electrode lifting range setting means for setting the lifting range of the electrode in a program manner;
A wattmeter for measuring the power supplied to the electrode;
The power supplied to the electrode by controlling the raising and lowering of the electrode and adjusting the voltage applied to the electrode according to the deviation between the target value of the power supplied to the electrode and the actual measured value of the power measured by the wattmeter. In the electric power control, the electric resistance type is provided with a power supply control means for giving priority to the control of the lifting / lowering of the electrode within the lifting / lowering range of the electrode over the adjustment of the applied voltage of the electrode. Melting control device for ash melting furnace. The melting control apparatus for an electric resistance ash melting furnace according to claim 3, further comprising power setting means for setting a target value of power supplied to the electrode in a program form. 5. The electric resistance ash melting furnace according to claim 3, wherein the electrode lifting range setting means sets the lifting range of the electrode so as to expand as the operation time elapses after the operation starts. Melting control device.

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