JP2938693B2 - Method for removing molten slag from incineration ash melting furnace - 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 removing molten slag from a municipal solid waste incineration ash melting furnace without closing the slag with a slag outlet.

[0002]

2. Description of the Related Art There is known an electric furnace type melting furnace for melting municipal waste incineration ash. FIG. 4 is a sectional view showing an example of a conventional electric furnace type incineration ash melting furnace.

[0003] In a conventional electric furnace type incinerated ash melting furnace (hereinafter referred to as "ash melting furnace") 1 shown in FIG.
The electrode 3 is provided in the furnace body 2 so as to be movable up and down, the electrode 3 is inserted into the incineration ash layer 4 put into the furnace main body 2, the incineration ash is melted and liquefied into molten slag and molten metal, and the molten slag layer 5 And a molten metal layer 6 is formed. Thereafter, while maintaining the tip of the electrode 3 at a certain distance from the surface of the molten slag layer 5, the incinerated ash is melted and melted by the arc heat generated between the electrode 3 and the molten metal layer 6. Liquefies into slag and molten metal. A slag port 9 is provided at a predetermined position on the furnace wall of the furnace body 2, and molten slag and molten metal are discharged by overflowing from the slag port 9 (hereinafter, referred to as “prior art”). In the prior art, since the incinerated ash is melted by the arc heat generated between the electrode 3 and the molten metal layer 6, the molten slag layer needs to be as thin as possible. For this reason, overflow from the slag port 9 is performed at any time.

The basicity of molten slag of municipal solid waste incineration ash is
Generally, it is around 0.4, and the viscosity is high even when the melting temperature is in a high temperature range, and it is difficult to flow when the slag is discharged outside the furnace. Therefore, in the prior art, the viscosity is lowered by means of heating the slag portion with an auxiliary heat source, or adjusting the basicity with CaO content or the like, to facilitate the flow.

[0005]

However, when the above measures are not taken, the smelt outlet is closed and the operation of the ash melting furnace becomes impossible. As described above, in the conventional ash melting furnace, an auxiliary heat source is required, and it is necessary to additionally input energy by melting the basicity adjusting agent together with the incinerated ash. Further, the basicity adjuster is expensive and economically disadvantageous.

Accordingly, an object of the present invention is to provide a molten slag of an incineration ash melting furnace capable of discharging molten slag without closing a slag outlet without using auxiliary heating or a basicity adjusting agent. It is to provide a slag removal method.

The present invention relates to an electrode arranged in a melting furnace.
Incineration ash injected by Joule heat generated when electricity is supplied
Insert the electrode into the molten slag layer formed by melting
And a high viscosity molten slag layer with a basicity of 0.6 or less
Of an electric incineration ash melting furnace forming a molten metal layer
A method for removing molten slag, comprising:
A slag port is provided on the furnace wall of the melting furnace so that
The opening of the slag outlet and / or the amount of incinerated ash
The molten metal surface of the molten slag layer by adjusting
While maintaining a height of 200 mm or more from the slag outlet,
It is characterized in that the molten slag is discharged directly from the slag port to the outside of the furnace .

[0008]

The present inventors have already developed an electric melting furnace utilizing Joule heat as a melting furnace for municipal waste incineration ash. In the present invention, an electric melting furnace utilizing this Joule heat is used. That is, first, an electrode is inserted into the incineration ash layer charged into the furnace, and the incineration ash is melted and liquefied into molten slag and molten metal. Thereby, a molten slag layer and a molten metal layer are formed. Thereafter, the tip of the electrode is inserted into the molten slag layer, and the incinerated ash is melted by Joule heat. The molten slag layer accumulated in the furnace has a predetermined thickness in order to utilize Joule heat. A slag port is provided on the furnace wall in the middle of the furnace in the height direction, and a certain level difference is secured between the molten metal surface of the molten slag layer and the slag port. The molten slag is extruded by the pressure of the slag (head pressure) and discharged from the slag port. Even with a highly viscous molten slag having a basicity of 0.6 or less, the slag can be continuously discharged without closing the slag opening. Control the amount of molten slag discharged from the slag port or the amount of incinerated ash to keep the level of the molten slag level so that the height difference between the molten slag surface and the slag outlet is always constant. To hold.

[0009]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an electric furnace type municipal waste incineration ash melting furnace showing an embodiment of the present invention, FIG. 2 is a cross-sectional view illustrating a slag outlet, and FIG. 3 is a front view of the same.

As shown in FIG. 1, an electrode 3 is vertically movable within a furnace body 2 of an electric furnace type municipal waste incineration ash melting furnace (ash melting furnace) 1. A slag port 7 is provided in a furnace wall at an intermediate portion in the height direction of the furnace main body 2. The electrode 3 is inserted into the incineration ash layer 4 to melt the incineration ash and liquefy it into molten slag and molten metal. Thereby, a molten slag layer and a molten metal layer are formed. After that, the molten slag layer 5
The incineration ash is melted by Joule heat and liquefied into molten slag and molten metal. Since the melting furnace used in the present invention utilizes Joule heat, the molten slag layer accumulated in the furnace has a predetermined thickness. The position of the molten metal level is adjusted so that a predetermined height difference can be secured between the slag outlet 7 and the molten metal level of the molten slag layer 5. The molten slag is discharged from the slag port 7 by the head pressure.

As shown in FIG. 1 to FIG.
A slag opening / closing mechanism 8 is provided. Outlet opening and closing mechanism 8
An annular base 8b provided at the outlet of the slag port 7 outside the furnace body 2, and a gate 8a slidable up and down provided outside the base 8b so as to close the opening of the base 8b. Consists of By adjusting the opening degree of the slag opening / closing mechanism 8, the amount of slag discharged from the molten slag is controlled. 10 is gate 8a and base 8b
This is an inlet / outlet of cooling water 11 for water-cooling. The amount of slag is controlled by the slag opening / closing mechanism 8 so as to balance the amount of incineration ash that is melted, the level of the molten surface of the molten slag layer 5 is kept constant, Maintain a constant head pressure by maintaining a constant height difference with the mouth 7.

Further, as a method of keeping the position of the molten metal surface of the molten slag layer 5 constant, a method of controlling the amount of incinerated ash to be charged into the furnace may be used.

As shown in the prior art, in the conventional ash melting furnace, the molten slag was discharged out of the furnace by falling under its own weight together with the molten metal by an overflow method. In the embodiment, the molten metal surface of the molten slag is adjusted such that the distance between the molten metal outlet 7 and the molten metal surface of the molten slag (the distance A shown in FIG. 1) is 200 mm or more. 7, the molten slag is extruded using the head pressure. Thereby, even if the molten slag has a high basicity of 0.6 or less, the slag can be continuously discharged without closing the slag opening 7. Therefore, a basicity adjuster and auxiliary heating means are not required.

[0014]

As described above, the present invention has the following industrially useful effects. Even with high viscosity molten slag having a basicity of 0.6 or less, slag can be removed without blocking the slag opening without using auxiliary means such as heating of the slag portion and use of a basicity adjusting agent. Since there is no need to heat the slag portion and use a basicity adjuster, it is economically advantageous without deteriorating the power consumption unit.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric furnace type municipal waste incineration ash melting furnace showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a slag port.

FIG. 3 is a front view illustrating a slag port.

FIG. 4 is a sectional view showing an example of a conventional electric furnace type incineration ash melting furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric furnace type municipal refuse incineration ash melting furnace 2 Furnace main body 3 Electrode 4 Incineration ash layer 5 Molten slag layer 6 Molten metal layer 7 Slag outlet 8 Slag opening and closing mechanism 8a Gate 8b Base 9 Slag outlet 10 Cooling water inlet Exit 11 cooling water.

Continuation of the front page (72) Inventor Kenichi Nishimura 5-7-12 Ichinomiya, Itoigawa-shi, Niigata (72) Inventor Tsuneo Yamashita 1-1-7, Kamigari, Itoigawa-shi, Niigata (56) References JP-A-61-168719 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23J 1/08 F23J 1/00 F27B 3/08 F27B 3/19

Claims (1)

(57) [Claims] 1. An electric current is applied to an electrode disposed in a melting furnace to generate electricity.
Melts the incinerated ash injected by Joule heat
Inserting the electrode into the formed molten slag layer,
High viscosity molten slag layer and molten metal of 0.6 or less
Of molten slag from electric incineration ash melting furnace that forms slag layer
A method wherein the liquid metal layer is above the liquid level
A slag port is provided on the furnace wall of the melting furnace so that
Adjust the opening of the slag and / or the amount of incinerated ash.
And the molten metal surface of the molten slag layer is
Melt from the slag port while maintaining the height at least 00 mm
A method for discharging molten slag from an incineration ash melting furnace, wherein the slag is directly discharged outside the furnace .