JP3077321B2 - Slag adhesion prevention method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing slag from adhering to electrodes of a waste melting furnace for melting incinerated ash such as municipal solid waste and industrial waste when electricity is cut off. .

[0002]

2. Description of the Related Art Incinerated ash produced after incineration of industrial waste such as municipal waste and sewage sludge is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-20 / 1987.
As disclosed in Japanese Patent No. 2923, melting is performed by arc heating with electrodes in a melting furnace to reduce the volume, and at the same time, harmful substances in the ash are contained to prevent pollution.

[0003]

By the way, the distance between the lower end of the electrode and the molten slag is adjusted by raising and lowering the electrode so as to make the impedance constant, thereby achieving a stable arc discharge. Since the lower end of the electrode and the molten slag surface are always located close to each other, the molten slag adheres to the lower end of the electrode and cools and hardens when the current supply is suddenly stopped as in the related art. Since the hardened slag is an insulating material, there is a problem that an arc discharge cannot be generated at the time of re-energization, and it takes much effort to remove the hardened slag when the current is stopped.

[0004]

An object of the present invention is to provide a method for preventing slag from adhering, which raises and lowers an electrode so as to make the impedance constant, adjusts the distance between the electrode and the molten slag, and adjusts the arc. in the waste melting furnace municipal waste incineration ash in the furnace was set to be melted by electric discharge, Lee
The method is characterized in that the electrode is unilaterally raised while the power is supplied regardless of impedance, thereby forming a long arc and then stopping the power supply.

[0005]

[Action] By raising the electrode unilaterally while the power is supplied regardless of the impedance, a long arc is generated at the lower end of the electrode, and when the lower end of the electrode is sufficiently separated from the molten slag surface, the power supply is stopped. No adhesion.

[0006]

Next, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, 1 is a furnace body, 2 and 2 ′ are electrodes suspended in the furnace body 1, and the electrodes 2, 2 ′ are supported by support arms 3, 3 ′, respectively. The support arm 3 is moved up and down by a lifting device 4 to vertically move the electrode 2 vertically. Further, the support arm 3 'can be moved up and down by an elevating device (not shown) to similarly elevate and lower the electrode 2'. In the furnace body 1, electrodes 2,
The molten slag 5 heated and melted by the arc discharge with the lower end of the 2 ′ is accumulated. Reference numeral 6 denotes incineration ash introduced into the furnace body 1.

A DC or AC current is applied to the electrodes 2 and 2 ′ from a power supply 7. The lifting device 4 raises and lowers the electrode 2 so that the impedance between the electrode 2 and the molten slag 5 is always constant, and adjusts the gap between the electrode 2 and the molten slag 5 (impedance control). Note that the electrode 2 'is also the electrode 2
Therefore, the electrode 2 will be described below.

In this waste melting furnace, when the power supply is stopped, the impedance control of the lifting / lowering device 4 is stopped, and the electrode 2 is moved at a predetermined speed (about 3 m / m) by the lifting / lowering device 4.
in about). As the electrode 2 rises, a long arc as shown in FIG. 2 is formed between the lower end of the electrode 2 and the molten slag 5, and the molten slag separates from the lower end surface of the electrode 2.

If the power supply is stopped in this state, the operation can be stopped without the molten slag adhering to the electrode 2, and the next start can be performed smoothly.

[0010] By increasing the applied voltage as the electrode 2 is raised, the long arc is more reliably formed, and a more desirable result can be obtained for wiping the molten slag.

[0011]

As described above, the method for preventing slag adhesion according to the present invention is advantageous in that the adhesion of molten slag can be prevented by a very simple operation of raising the electrode before stopping the energization, and the energization at the time of restart is facilitated. Has a significant effect.

[Brief description of the drawings]

FIG. 1 is a power supply system diagram of a waste melting furnace.

FIG. 2 is a schematic view of the inside of a furnace when an electrode is raised.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace 2 Electrode 3 Support arm 4 Lifting device 5 Melting slag 7 Power supply device

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05B 7/144 F23G 5/00 115 F23G 5/50 F23J 1/08

Claims (1)

(57) [Claims] 1. A waste melting furnace in which an electrode is moved up and down so that impedance becomes constant to adjust a gap with a molten slag, and an arc discharge melts municipal incineration ash and the like in the furnace. Through regardless of impedance
Rongua electrodes while still collecting by unilaterally increased
A method for preventing slag from adhering to an electrode in a waste melting furnace, comprising: