JPH09318279A - Electrode seal device for ash melt furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent penetration of a salt in a refractory material in the vicinity of an electrode insertion hole and to keep complete electric insulation by a method wherein a seal formed of a refractory material having porosity lower than that of a refractory material arranged at the furnace wall of an ash melt furnace is fitted in the periphery of an electrode insertion hole formed in the furnace cover of an ash melt furnace. SOLUTION: Incinerated ash 13 charged in an ash melt furnace 1 is heated and molten through DC energization of an upper electrode 6 and a furnace bottom electrode 6a from a power source 16 to generate molten slag 14. By keeping the temperature of the molten slag 14 in the ash melt furnace 1 at an optimum temperature of 1,200-1,300 deg.C, the surface temperature of the refractory material of the furnace wall 2 is also raised to 1,000 deg.C. When incinerated ash 13 is molten, a salt is vaporized and adhered to the refractory material and the molten salt is penetrated therethrough. Since a seal 7 having a low porosity is located between the periphery of the electrode insertion hole 8 of a furnace cover 3 and an upper electrode 6 and the molten salt is not penetrated in the seal 7, insulation ability is kept and energization is not effected between the upper electrode 6 and the furnace bottom electrode 6a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode sealing device for an ash melting furnace for melting and treating incineration ash discharged from municipal waste incinerators and various incinerators.

[0002]

2. Description of the Related Art Wastes such as municipal solid waste and sewage sludge are incinerated in an incinerator, and the incinerated ash and dust produced are conventionally landfilled. However, because of the problems of depletion of landfill sites and pollution of groundwater due to elution of harmful heavy metals, there is an increasing need for volume reduction and volume reduction and detoxification by melting.

Against this background, residual carbon in incinerated ash,
An ash melting furnace that uses coke, kerosene, and electric power as a heat source to melt and incinerate incinerated ash discharged from an incinerator or the like has been proposed, and some of them are actually processed.

Among these, the ash melting furnace using electric power as a heat source includes a plasma arc heating system and a resistance heating system.

A plasma arc heating type melting furnace is provided with a hollow graphite electrode penetrating the top furnace lid, the tip of the electrode is located near the upper surface of the molten slag, and the hollow portion of the electrode is provided with Ar.
Gas or N ₂ gas is caused to flow from above, and a direct current is passed between the graphite electrode at the top and the furnace bottom electrode to maintain the arc by the plasma-forming gas flow and heat and melt the incineration ash. This melting furnace has the characteristics that the electrode has a long life and the melting speed is large, and the melting furnace can be made compact, but before the melting, the incinerated ash and dust are scattered by the gas flow, and the dust collector is heavily burdened. There is a problem.

In the resistance heating type ash melting furnace, a counter electrode is arranged in the molten slag, and the incineration ash is heated and melted by electric resistance heat (Joule heat) due to direct current or alternating current. It has features that there is little gas, flicker does not occur because no arc is generated, and that molten slag and molten metal can be separated and separated.

FIG. 2 is a longitudinal sectional view of a conventional resistance heating type ash melting furnace electrode sealing device. In the figure, a is an ash melting furnace. The furnace wall b of the ash melting furnace a is entirely formed of a refractory material such as refractory brick. The incinerated ash n is charged from the ash charging port e of the ash charging pipe d provided in the furnace lid c of the ash melting furnace a. The incinerated ash n put into the ash melting furnace a is
The upper electrode j inserted into the electrode insertion hole m provided in the furnace lid c of the ash melting furnace a and the furnace bottom electrode k buried in the furnace bottom of the ash melting furnace a.
To heat the molten slag o. When the required amount of molten slag o is accumulated in the ash melting furnace a,
The molten slag o is discharged to the outside through a discharge port h provided in the lower part of the furnace wall of the ash melting furnace a by the head pressure applied by its own weight. f is an exhaust pipe provided in the furnace lid c of the ash melting furnace a, and g is an exhaust port. p is molten metal accumulated in the bottom of the ash melting furnace a, and when a required amount is accumulated like the molten slag o, it is discharged to the outside through the discharge port i. q is a refractory water cooling jacket provided in a part of the furnace wall b above the upper surface level of the molten slag o in the ash melting furnace a, and r is a water cooling pipe buried in this water cooling jacket q. When the ash is melted, the salt in the ash penetrates into the refractory material, so it exhibits high conductivity. Therefore, the refractory water cooling jacket q cools a part of the furnace wall b and solidifies salts adhering to the inner surface of the furnace wall b to prevent the salt from penetrating into the interior. It is designed to prevent electrical conduction. Reference numeral s is a power source for direct current application to the top electrode j and the bottom electrode k, and t and u are their electric wires. In addition to this conventional example, there is also one in which a slag port h is provided at a central portion in the height direction of a furnace wall b of an ash melting furnace a to cause the molten slag o to overflow at any time to discharge the slag.

For the furnace wall b and the furnace lid c of the ash melting furnace a, a high alumina refractory material having a porosity of 20% to 30% is generally used.

[0009]

However, in the ash melting furnace as shown in FIG. 2, the water cooling jacket provided in the furnace wall cools the salts that volatilize during ash melting and adhere to the inner surface of the ash melting furnace. Although the solidification is made to prevent the penetration of the portion into the refractory material, the penetration cannot be sufficiently prevented, so that the electric insulation between the upper electrode and the furnace bottom electrode cannot be performed completely. In addition, it is not preferable in terms of safety because water is used in the furnace wall of the ash melting furnace, and further, the temperature of the molten slag in the ash melting furnace is lowered due to cooling, which wastes energy and is not preferable in terms of thermal efficiency. There are problems such as.

The present invention was devised to solve the above-mentioned problems, and prevents permeation of salts into the refractory material around the electrode insertion hole and maintains complete electrical insulation, thereby improving the upper part. It is an object of the present invention to provide an electrode sealing device for an ash melting furnace that prevents a short circuit from occurring between the electrode and the furnace lid.

[0011]

In order to achieve the above object, according to the present invention, there is provided an electrode sealing device for an ash melting furnace for melting incinerated ash, the electrode being provided on a furnace lid of the ash melting furnace. An electrode sealing device for an ash melting furnace, characterized in that a seal formed of a refractory material having a lower porosity than the refractory material provided on the furnace wall of the ash melting furnace is fitted around the insertion hole. Provided.

The seal is preferably made of a refractory material having a porosity of 1% or less.

According to the above-mentioned structure of the present invention, when the incineration ash put into the ash melting furnace is melted, the periphery of the electrode insertion hole of the furnace lid and the upper electrode are insulated with a seal to make the upper electrode and the furnace lid. Since the short circuit between the refractory material and the upper electrode is prevented even if salt penetrates into the refractory material of the furnace wall and furnace lid, it is possible to prevent a short circuit from the refractory material to the upper electrode. Since the melting of the refractory material is prevented by the arc, the life of the refractory material, in particular, the refractory material of the furnace lid can be extended. In addition, since water is not used in the furnace wall of the ash melting furnace, it is safe, and since it is not cooled, the temperature of the molten slag in the ash melting furnace is set to the optimal temperature of 1,200 ° to 1,300.
It can be kept at ° C and there is no waste of energy.

According to an experiment, the seal is made of a refractory material having a porosity of 1% or less, so that the seal can be more completely insulated from the upper electrode.

[0015]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention and is a vertical cross-sectional view of an electrode sealing device for an ash melting furnace according to the present invention. In the figure, reference numeral 1 denotes an ash melting furnace for melting and processing incinerated ash. Reference numeral 2 denotes a furnace wall of the ash melting furnace 1, which is entirely made of refractory brick. Reference numeral 3 is a furnace lid provided on the top of the ash melting furnace 1. Reference numeral 4 denotes a slag spout provided at a lower portion of the wall portion 2 of the ash melting furnace 1, and the molten slag 1
4 is discharged from this outlet 4. Reference numeral 5 is a molten metal discharge port provided at the bottom of the wall 2 of the ash melting furnace 1. The molten metal 15 separated from the molten slag 14 and accumulated in the bottom portion of the ash melting furnace 1 slags the molten slag layer 14 and then generates an arc between the molten slag layer 14 and the electrode 6 to melt the metal. It is discharged to the outside through the outlet 5. Reference numeral 6 denotes an upper electrode, which is inserted into an electrode insertion port 8 of a seal 7 provided on the furnace lid 3 on the top of the ash melting furnace 1. Reference numeral 6a denotes a furnace bottom electrode which is embedded in the bottom of the ash melting furnace 1 so as to face the upper electrode 6. 1
3 is an ash charging port 10 of an ash charging pipe 9 provided at the top of the ash melting furnace 1.
It is the incinerated ash that was thrown in from, and is in a state of floating above the molten slag 14 in the unmelted state. Since the electric resistance in the molten metal layer 15 is extremely smaller than that in the molten slag layer 14, Joule heat generation is small in this portion, most of the metal is solid, and only the upper surface is slightly melted. Reference numeral 16 is a power source for applying a direct current to the upper electrode 6 and the furnace bottom electrode 6a, and 17 and 17a are its electric wires. In addition, 11 is an exhaust pipe and 12 is an exhaust port.

The molten slag 14 is heated by the Joule heat generated by the energization of the electrode 6 when the molten slag 14 is slagged, and the temperature is adjusted, and the amount of slag is changed to control the amount of slag. You can also

The seal 7 is made of ceramics such as alumina ceramics and fine ceramics (for example, silicon nitride) and has a porosity sufficiently lower than that of refractory bricks used for the furnace wall 2 and furnace lid 3. Refractory materials are used. In addition, if a refractory material having a porosity of 1% or less is used, electrical insulation can be more completely achieved.

Next, the operation based on the embodiment will be described. The incineration ash 13 put into the ash melting furnace 1 is supplied to the power source 1
A direct current is applied to the upper electrode 6 and the furnace bottom electrode 6a from 6 and the molten slag 14 is generated by heating. The temperature of the molten slag 14 in the ash melting furnace 1 is set to the optimal temperature of 1,200 ° to 1,3.
If the temperature is kept at 00 ° C, the surface temperature of the refractory material on the furnace wall 2 also rises to about 1,000 ° C. When the incineration ash 13 is melted, salts are evaporated and adhered to the refractory material, and the molten salt permeates. However, around the electrode insertion hole 8 of the furnace lid 3 and the upper electrode 6
There is a seal 7 having a low porosity between and
Since the molten salt does not penetrate into, the insulation is maintained,
No electricity is passed between the upper electrode 6 and the furnace bottom electrode 6a.

The present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0020]

As described above, according to the present invention, when melting the incineration ash put in the ash melting furnace, the periphery of the electrode insertion hole of the furnace lid and the upper electrode are provided on the furnace wall. Since the seal formed of the refractory material having a porosity lower than that of the refractory material is used for insulation, a short circuit does not occur and the life of the refractory material can be extended. Further, since water is not used in the furnace wall of the ash melting furnace, it is safe, and since it is not cooled, the temperature of the molten slag in the ash melting furnace can be kept at an optimum temperature, and energy is not wasted. If the seal is made of a refractory material having a porosity of 1% or less, the furnace lid and the upper electrode can be more completely insulated. It has excellent effects such as.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electrode sealing device for an ash melting furnace according to the present invention.

FIG. 2 is a vertical sectional view of a conventional ash melting furnace.

[Explanation of symbols]

 1 Ash melting furnace 2 Furnace wall 3 Furnace lid 4 Slag outlet 5 Metal outlet 6 Upper electrode 6a Furnace bottom electrode 7 Seal 8 Electrode insertion hole 9 Incinerated ash inlet pipe 10 Incinerator ash inlet 11 Exhaust pipe 12 Exhaust outlet 13 Incinerator ash 14 Molten slag 15 Molten metal 16 Power supply 17,17a Electric wire a Ash melting furnace b Furnace wall c Furnace lid d Incinerated ash input pipe e Incinerated ash input port f Exhaust pipe g Exhaust port h Dust outlet i Discharge port j Upper electrode k Furnace Bottom electrode m Electrode insertion port n Incineration ash o Molten slag p Molten metal q Water cooling jacket r Water cooling pipe s Power supply t Electric wire u Electric wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuaki Matsuzawa 1 Shinshinarahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishi Kawashima Harima Heavy Industries Ltd. Technical Research Institute (72) Kenichi Tahara Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa No. 1 Ishi Kawashima Harima Heavy Industries Ltd. Technical Research Center

Claims (2)

[Claims] 1. An electrode sealing device for an ash melting furnace for melting incinerated ash, wherein the refractory material is provided on a furnace wall of the ash melting furnace around an electrode insertion hole provided in a furnace lid of the ash melting furnace. An electrode sealing device for an ash melting furnace, characterized in that a seal made of a refractory material having a lower porosity than the above is fitted. 2. The electrode sealing device for an ash melting furnace according to claim 1, wherein the seal is made of a refractory material having a porosity of 1% or less.