JP2785292B2 - How to control the amount of slag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is intended to facilitate control of the amount of slag from a slag outlet when discharging molten slag from a melting furnace for melting and processing waste. And a method for controlling the amount of slag that has been improved.

[Related Art] Conventionally, a melting furnace for melting and processing waste products such as waste products discharged from factories and mines, municipal waste incineration residues, and sewage sludge incineration residues has been used. When the molten slag in the melting furnace is discharged from the slag port, the molten slag or the like solidified in the vicinity of the slag port may hinder the discharge from the slag port. In view of the above, there has been proposed a device capable of promptly discharging the waste from the slag outlet. For example, as disclosed in Japanese Patent Application Laid-Open No. 58-40791, an auxiliary discharge electrode is provided so as to be able to protrude and retract toward the inside of the furnace body in the vicinity of the slag outlet, and when the molten slag is discharged, the auxiliary electrode is energized to change the molten state. It is formed to the vicinity of the slag outlet to facilitate discharge, and the amount of slag from the slag outlet is controlled by controlling the opening amount by the slag amount adjustment nozzle provided at the slag outlet. Was.

[Problem to be Solved by the Invention] In such a conventional apparatus, when the amount of slag is relatively large, control for continuously maintaining the amount of slag can be performed. The control was difficult. For example, when the amount of slag is small, the molten slag is cooled and easily solidified, and the slag is blocked by the solidified slag at the slag outlet, or when the opening amount of the slag amount adjusting nozzle is increased, the nozzle is moved. In some cases, a large amount of molten slag flowed out together with the solidified slag that had been clogged, and a suitable amount of slag could not be adjusted. In addition, when the opening amount is adjusted by the slag amount adjusting nozzle, the slag amount adjusting nozzle is locally melted and damaged, and it has to be replaced every time.

Accordingly, an object of the present invention is to provide a method for controlling the amount of slag that can easily control the amount of slag discharged from a slag outlet over a wide range.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following method to solve the problems. That is, when the main electrode provided in the furnace body into which the waste is charged is energized to melt the waste and the molten slag is discharged from a slag port provided in the furnace body, the slag is removed. At the same time as heating the molten slag discharged from the slag port while energizing the auxiliary electrode formed to be smaller than the inner diameter of the port and protruding and retracting in the slag port, This is a method for controlling the amount of slag, wherein the amount of slag is controlled by causing the slag to appear in the slag port.

[Operation] In the method for controlling the amount of slag, the main electrode melts the waste put into the furnace body, and when the molten slag is discharged, the auxiliary electrode heats the molten slag discharged from the slag outlet and discharges the molten slag. An auxiliary electrode having an outer diameter smaller than the inner diameter of the slag port is made to protrude and retract from the slag port to control the amount of the slag.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a melting furnace which is an embodiment to which the slag amount control method of the present invention is applied. Reference numeral 1 denotes a furnace main body. The furnace main body 1 includes a furnace shell 2 and a furnace refractory 4. Inside the furnace shell 2, the furnace refractory 4 having a predetermined thickness is made of a refractory material such as alumina or zirconia. The container has been constructed. Further, a pair of main electrodes 6 and 8 are provided at the same horizontal height so as to face each other inside the furnace main body 1. Main electrode 6,8
For example, materials such as heat-resistant steel, artificial graphite, and molybdenum are used. An AC power supply 10 having a thyristor power control circuit is connected to the pair of main electrodes 6 and 8. When an electric current flows through the molten slag 32 in the furnace main body 1, a joule due to the electric resistance of the molten slag 32 is formed. Waste from heat generation
11 is configured to melt.

Further, a slag port 12 is formed at the bottom of the furnace main body 1 so that the furnace space 2 and the furnace refractory 4 are inserted into the furnace main body 1 to communicate the inside of the furnace main body with the outside. A set of emergency shut-off doors 18, in which communication holes 14, 16 having substantially the same diameter as the slag port 12 are formed outside the furnace shell 2,
20 is provided slidably. This emergency shutoff door 1
Reference numerals 8 and 20 are configured to be slid by an unillustrated drive mechanism when the slag port 12 is urgently shut off to close the slag port 12.

Auxiliary electrodes 22 are provided through the communication holes 14 and 16 of the emergency shutoff doors 18 and 20 and further through the slag port 12 so as to be able to come and go from the outside of the furnace body 1 to the inside. The auxiliary electrode 22 includes
Heat-resistant steel, artificial graphite, molybdenum and the like are used. A connecting member 24 is connected to an end of the auxiliary electrode 22 outside the furnace main body 1, and the connecting member 24 is configured to be freely movable in its axial direction by a driving device 26. Then, a pair of contact rollers for energizing the auxiliary electrode 22 that appears and disappears
An auxiliary power supply having a thyristor power control circuit is provided between the contact roller 28 and the one main electrode 8.
30 is connected.

In the present embodiment, when the waste 11 is melted in the furnace body 1, a part of the melted slag 32 is cooled and solidified in the vicinity of the slag port 12 to become a solidified slag 34. . The diameter of the slag port 12 and the auxiliary electrode 22 is determined so that the molten slag 32 is not discharged by the auxiliary electrode 22 and the solidified slag. Then, as shown in FIG. 1, the auxiliary electrode 22 is configured to be inserted into the furnace main body 1 to a position where it can be energized via the solidified slag 34 between the auxiliary electrode 22 and the main electrode 8. . Further, as shown in FIG. 2, the auxiliary electrode 22 is
The communication hole 16 communicates with the slag port 12. At this time, the opening amount of the communication hole 16 communicating with the slag port 12 can be adjusted.

Further, above the main electrodes 6, 8 on the upper part of the furnace body 1,
An auxiliary slag port 36 is formed.

Next, the operation of the melting processing furnace of the present embodiment will be described.

First, waste 11 is charged into the furnace body 1. Examples of the waste 11 include ash for incineration of municipal waste and ash for incineration of sewage sludge, and contain metal oxides such as iron, magnesium, and calcium. After an initial molten material having an appropriate resistance value is previously charged into the furnace main body 1, energization is started by the main power supply 10 and Joule heat is generated due to the electric resistance of the initial molten material between the main electrodes 6 and 8. Thus, a molten slag 32 is formed.
Thereafter, the wastes 11 are charged and sequentially melted. Heavy components in the molten waste 11 are converted into molten slag, and the furnace body 1
Collect at the bottom of the. At this time, the molten slag near the slag port 12
32 is cooled and solidified to form solidified slag 34, which together with the auxiliary electrode 22 closes the slag port 12. Therefore, the slag port 12
The molten slag 32 is not discharged from. Then, light components, for example, the salt 38 accumulate in the upper part of the furnace main body. This salt
When 38 accumulates, it is discharged from the auxiliary slag port 36 as appropriate.

It is necessary to adjust the height of the molten slag layer in the furnace body 1 in order to continuously treat the waste 11 and to appropriately discharge the salt 38 from the auxiliary slag port 36. Therefore, when an appropriate amount of the molten slag 32 is accumulated, the molten slag 32 is discharged to the outside of the furnace main body 1.

At the time of this discharge, energization is started by the auxiliary power supply 30. Since the auxiliary electrode 22 and one of the main electrodes 8 are electrically connected by the molten slag 32 or the like, the current flows in the molten slag 32 and Joule heat is generated by the electric resistance of the molten slag 32. I do. Due to this heat, the solidified slag 34 is sequentially melted, and the molten slag 32 is quickly discharged to the outside of the furnace body 1 through the space between the slag port 12 and the auxiliary electrode 22. By introducing new waste 11 into the furnace body 1 while discharging, the waste 11 can be continuously melted.

At the time of discharge, the driving device 26 moves the auxiliary electrode 22 through the connecting member 24 in a direction in which the auxiliary electrode 22 is pulled out from the slag port 12, and as shown in FIG.
Adjust the amount of opening. That is, the end of the auxiliary electrode 22 and the communication hole
The gap between the slag 32 and the auxiliary electrode 22 is brought into and out of contact with the auxiliary electrode 22 so that the amount of the molten slag 32 discharged through the slag port 12 is controlled. When the auxiliary electrode 22 is moved toward the inside of the furnace main body 1, the amount of slag is reduced, and when the auxiliary electrode 22 is moved in the opposite direction, the amount of slag is increased.

At this time, the auxiliary power supply 30 keeps energizing between the auxiliary electrode 22 and one of the main electrodes 8 via the molten slag 32. As a result, the molten slag 32 passing through the slag port 12
Is heated, is not cooled by passing through the slag port 12, and the molten slag 32 does not solidify. Therefore, even if the opening amount is considerably reduced by the auxiliary electrode 22 and the amount of slag is controlled to a small amount, the molten slag 32 does not solidify into the solidified slag 34, so that the molten slag The state is kept uniform, and it can be controlled so that the amount of slag is small.

When the discharge is stopped, as shown in FIG. 1, if the auxiliary electrode 22 is inserted to the inside of the furnace main body 1 and the energization is stopped, the molten slag 32 is naturally cooled and the slag outlet is opened. Solidified slag 34 is formed between the electrode 12 and the auxiliary electrode 22, and the slag port 12 is closed.

In this embodiment, the diameter of the slag port 12 is 40 mm, the diameter of the auxiliary electrode 22 is 22 mm, the load voltage is 50 V, the load current is 80 A, the load input power is 4 kW, and the temperature of the molten slag 145 discharged from the slag port 12 is 145.
When the temperature was set to 0 ° C., the amount of slag was reduced to a minimum of 45 kg / h, and the slag could be stably and continuously discharged. With the conventional slag amount adjustment nozzle, it was possible to stably and continuously slag only up to a minimum of 150 kg / h. The amount of slag can be adjusted over a wide range.

In the above-described embodiment, the auxiliary electrode 22 is energized at the time of discharge, so that the solidified slag 34 is melted, so that there is no need to provide an opening / closing door or the like for closing the slag port 12.
As the solidified slag 34 is melted, the auxiliary electrode 22 is moved in a direction in which the solidified slag 34 is pulled out from the slag port 12, and the solidified slag 34 in the slag port 12 is rapidly discharged while expanding the melting of the slag 34. However, when the closing of the slag port 12 at the time of melting is performed by other means, the position of the auxiliary electrode 22 can be adjusted near the communication hole 16 communicating with the slag port 12 to reduce the amount of slag. It is enough if it can be controlled.

In addition, in place of the one main electrode 8 described above, another auxiliary electrode is provided at the bottom of the furnace main body 1, and a current flows between the another auxiliary electrode and the auxiliary electrode 22 in the same manner as described above. ,
It is feasible. Further, as shown in FIG. 3 as a second embodiment, an auxiliary electrode 46 having a tapered portion 44 between the small diameter portion 40 and the large diameter portion 42 may be used instead of the auxiliary electrode 22 described above. For example, the diameter of the small diameter portion 40 is 22 mm, and the diameter of the large diameter portion 42 is
44 mm, the diameter of the slag port 12 is 40 mm, the taper portion 44 allows the opening amount of the communication hole 16 communicating with the slag port 12 to be adjusted more finely, and the amount of slag can be finely controlled. . Further, as a third embodiment, as shown in FIG. 4, a cooling jacket 52 having a tapered portion 50 may be provided on the auxiliary electrode 22 described above. The cooling jacket 52 is moved in and out together with the auxiliary electrode 22 so that the taper 50 allows the opening of the slag port 12 to be adjusted more finely and the amount of slag to be adjusted finely. Moreover, by circulating the coolant inside the cooling jacket 52, the molten slag
The durability of the auxiliary electrode 22 and the tapered portion 50 can be improved by preventing the tapered portion 50 from being damaged by 32.

Further, in the above-described embodiment, the direct energization type melting processing furnace is described. However, the present invention is not limited to this case, and an arc type melting processing furnace can be similarly implemented. In addition, the slag port 12
In the case where there are a plurality of slags, if an auxiliary electrode is similarly provided at each of the slag outlets, it is possible to discharge the molten slag while controlling the amount of slag in the same manner.

As described above, in the melting processing furnace of the present embodiment to which the slag amount control method of the present invention is applied, at the time of discharge, the auxiliary electrode 22 is protruded and retracted to adjust the opening amount, and the amount of slag discharged from the slag outlet 12. Therefore, there is no need to provide a special adjustment member such as a slag amount adjustment nozzle. . At this time, the auxiliary electrode 22 is energized at the same time, so that the molten slag 32
By heating the molten slag 32 passing through the slag port 12, the slag 32 is prevented from being cooled and solidified. be able to.

The emergency shutoff doors 18 and 20 provided in this embodiment are provided for safety in consideration of, for example, a case where the auxiliary electrode 22 is damaged for some reason and urging should be stopped urgently. Yes, it is not used for ordinary discharge of molten slag.

Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and it is needless to say that the present invention can be implemented in various modes without departing from the paper of the present invention.

[Effects of the Invention] As described in detail above, the slag amount control method of the present invention controls the amount of slag from the slag outlet by making the auxiliary electrode protrude and retract. At this time, by simultaneously energizing the auxiliary electrode, the molten slag passing through the slag port is heated to prevent the molten slag passing through the slag port from being cooled and solidified, and the state of the molten slag is made uniform. , And even if the amount of slag is controlled to be small, the slag can be stably and continuously discharged, and the amount of slag can be adjusted over a wide range. Also, since the outer diameter of the auxiliary electrode is smaller than the inner diameter of the slag port, the auxiliary electrode can be inserted into the furnace body through the slag port,
By applying electricity between the main electrode and the auxiliary electrode, the solidified slag closing the slag port is melted, and the molten slag can be discharged from the slag port.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a melting furnace as one embodiment to which the method of the present invention is applied, FIG. 2 is a schematic perspective view of a slag port and an auxiliary electrode of the present embodiment, and FIG. FIG. 4 is a partial schematic configuration diagram of a melting processing furnace as an example, and FIG. 4 is a partial schematic configuration diagram of a melting processing furnace as a third embodiment. 1 ... furnace body, 6, 8 ... main electrode 11 ... waste, 12 ... slag port 22 ... auxiliary electrode, 32 ... molten slag

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F23G 5/00 115 B09B 3/00 303 H05B 3/60

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein a main electrode provided in the furnace body into which the waste is charged is energized to melt the waste and discharge the molten slag from a slag port provided in the furnace body. At the same time as heating the molten slag discharged from the slag port while energizing an auxiliary electrode formed to have an outer diameter smaller than the inner diameter of the slag port and provided in the slag port so as to be able to protrude and retract, the auxiliary A method for controlling the amount of slag, wherein the amount of slag is controlled by making an electrode protrude and retract from the slag outlet.