JP2003056831A - Discharge method and device for waste melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge method and device for a waste melting furnace in which slag in a stable form can be produced and molten materials can be continuously discharged. SOLUTION: In the discharge method for molten materials, a rear furnace 4 for storing the molten materials is provided adjacently to the melting furnace 1 for waste or ash obtained by incinerating the waste. The bottom part of the melting furnace communicates with the rear furnace through communicating pipes for the molten materials and molten slag and molten metal are discharged respectively from outlet ports 8 and 9 provided in the rear furnace 4. At least two communicating pipes 5 are provided at suitable intervals and an induction heater 6 is provided between the communicating pipes 5. Induction current is supplied to a loop formed by the communicating pipes 5, the melting furnace 1 and the molten metal stored in the bottom of the rear furnace to heat the molten metal.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the production of slag by directly melting waste such as municipal waste, industrial waste and sludge,
Alternatively, the present invention relates to a discharge method and an apparatus for a waste melting furnace in which waste is once incinerated into ash and then melted to produce slag.

[0002]

2. Description of the Related Art At present, most wastes are treated by an incineration system, but the incineration system has a drawback that it requires a disposal site for incinerated ash. Especially in metropolitan areas, it is difficult to secure a disposal site for incineration ash.
There is an increasing need to treat incinerated ash of waste by melting it to reduce its volume and to treat it with a method that can be recycled. In order to recycle slag obtained by melting waste, it is necessary to have physical and chemical properties similar to those of natural sand and crushed stone, and to have little fluctuation in properties. Furthermore, it is a necessary condition that no metal is mixed into the slag and that no heavy metal is eluted.

In order to produce slag having stable properties, it is necessary to provide a slag storage portion in a molten state to secure a residence time, completely melt the slag, and continuously discharge the slag.

From the viewpoint of operation, a method of continuously discharging molten slag that does not require opening and closing work is desirable. Conventionally, as a method for discharging slag and metal (metals such as iron) obtained by melting waste from a melting furnace, as shown in JP-A-49-98070 (conventional method 1), it is always open. It is known to continuously discharge slag and metal through a slag spout. Further, there is a method of continuously discharging a melt pool and a slag spout outside the melting furnace by heating with an induction heating device, as disclosed in JP-A-9-9.
6410 (conventional method 2) and JP-A-10-160.
No. 137 (conventional method 3).

[0005]

In the conventional method 1, since the molten slag and metal are discharged without staying in the furnace, unmelted matter is mixed in the slag, which hinders effective utilization.

Further, in the conventional method 2, a melting material storage portion is provided in the melting furnace and the heat retaining furnace, and a heating unit is provided. However, heating means is provided in a portion connecting the melting furnace main body and the heat retaining furnace. Since it does not exist, there is a drawback that the narrowest flow path portion is blocked due to a temperature decrease or the like and operation becomes impossible.

Further, in the conventional method 3, a connecting path connecting the bottom of the heat-retaining furnace and the bottom of the melting furnace main body is provided, and a heating device is provided in the middle of the connecting path. There are drawbacks such as large loss, easy occurrence of troubles such as blockage, and complicated maintenance of flow path due to complicated shape.

[0008] Therefore, the present invention provides a discharge method and apparatus for a waste melting furnace which can produce slag having stable properties and discharge the melt continuously.

[0009]

A method for discharging a waste melting furnace according to the present invention is provided with a post furnace for storing the melt adjacent to a melting furnace for waste or ash incinerated from the waste, and a bottom of the melting furnace. In the method for discharging a molten material, the molten material is communicated with the post-reactor through a communication pipe, and the molten slag and the molten metal are continuously discharged from respective discharge ports provided in the post-reactor. At least two communication pipes are provided at appropriate intervals, an induction heating device is provided between the communication pipes, and an induction current is generated in a loop formed by the molten metal stored in the communication pipe, the melting furnace, and the bottom of the post furnace. It is characterized in that the molten metal is heated by flowing. In the above structure, a U-shaped communication pipe is provided in the metal storage portion of the furnace bottom of the melting furnace, and the induction heating device provided in the communication pipe converts the molten metal formed into a loop shape between the communication pipe and the bottom of the melting furnace. The molten metal at the bottom of the furnace may be heated by passing an induction current.

Further, the discharge device of the waste melting furnace of the present invention is a melt discharge device of a waste furnace or an ash melting furnace in which waste is incinerated, and is a post furnace for storing the melt adjacent to the melting furnace. Providing two or more linear communication pipes that connect the bottom of the melting furnace to the melt stored in the post furnace, and provide a molten slag discharge port and a molten metal discharge port in the post furnace to heat the molten metal An induction heating device is installed in the communication tube to create a magnetic flux surrounding the communication tube so that an induction current flows in the loop formed by the communication tube and the molten metal stored in the melting furnace and the bottom of the post furnace. And an induction heating coil surrounding the iron core. In the above configuration, a U-shaped communication pipe is provided in the metal storage portion of the furnace bottom of the melting furnace, the opening of the communication pipe is connected to the molten metal storage portion of the furnace bottom, and the communication pipe and the melting furnace bottom are connected. An induction heating device may be provided, which includes an iron core for forming a magnetic flux so as to surround the communication tube and an induction heating coil surrounding the iron core so that an induction current flows through the molten metal formed in a loop shape. It is possible to provide a device for blowing a gas containing oxygen into the molten material storage part.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, in order to produce a slag having stable properties, a slag storage portion in a molten state is provided to secure a residence time, completely melt, and continuously discharge. There is a need. Also from the viewpoint of operation, a method of continuously discharging molten slag is desirable.

In the present invention, in order to provide a molten material storage portion in the melting furnace, a post-furnace for storing the melted material is provided, and two or more pieces for connecting the melted material stored in the bottom of the melting furnace main body to the melted material stored in the post-heating furnace are provided. A straight communication tube is provided, and a melt outlet is provided in the post furnace.

By providing the melt outlet of the post furnace at a position higher than the bottom of the melting furnace, a molten material reservoir is formed at the bottom of the melting furnace. The higher the position of the molten slag discharge port of the post furnace, the larger the amount of molten slag stored in the furnace bottom of the melting furnace and the longer the residence time, so that the melt can be completely melted.

In order to discharge the melt continuously, it is necessary to maintain the temperature of the melt at about 1350 ° C. or higher. However, since the waste of the object to be melt-processed changes in water content, heat generation amount, etc., the temperature of the melt also changes. Therefore, a heating device corresponding to the temperature change of the melt is required. In particular, a heating device is required because the flow passage is thinnest in the communicating portion between the furnace bottom of the melting furnace and the post furnace and is easily blocked.

The present invention is characterized in that an induction heating device for directly heating the melt in the communicating pipe is provided. That is,
As shown in FIG. 1, an induction heating coil is provided between two communication pipes, an iron core for inducing magnetic flux is provided in the induction heating coil, and the iron core surrounds the circumference of one communication pipe to make one turn. To form. When an alternating current is applied to the induction heating coil,
The magnetic flux is generated in the iron core, and the magnetic flux is generated so as to go around the communication pipe along the iron core. As a result, a current flows through the loop-shaped molten metal formed by the two communicating pipes, the molten furnace furnace bottom, and the molten metal of the post furnace to heat the molten metal.

The heated molten metal flows by buoyancy and electromagnetic force. By heating the molten metal, the molten slag in contact therewith is also heated. Also,
Since the communication pipe that connects the melting furnace and the post furnace is connected in a straight line for the shortest distance, the length is short and the shape is simple, so there is no trouble such as blockage and maintenance is easy.

When the size of the melting furnace main body is large, it becomes difficult to maintain the entire furnace bottom of the melting furnace at a high temperature by only heating the communicating pipe for discharging the melt. In that case,
A U-shaped connecting pipe is provided in the metal storage part on the bottom of the melting furnace.
An induction heating device is provided so that an induction current flows through a molten metal formed in a loop shape between the communication pipe and the bottom of the melting furnace. That is, an induction heating device including an iron core for forming a magnetic flux so as to surround the communication tube and an induction heating coil surrounding the iron core is provided. If the melting furnace is large, a plurality of melting furnaces may be provided if necessary.

In the present invention, a device for blowing a gas containing oxygen is provided in the melt storage part of the post furnace. After the waste is melted in a reducing atmosphere to volatilize the heavy metal, the residual heavy metal such as low concentration lead is converted into a sparingly soluble oxide by blowing a gas containing oxygen, and the tertiary metal of SiO _{2 in} the slag By incorporating it into the original mesh structure, it is possible to prevent the elution of heavy metals from the slag.

In the above-mentioned conventional method 3, the induction heating device is installed at the bottom of the melting furnace. However, there is often a floor or other device under the bottom of the melting furnace, and the devices interfere with each other. In order to avoid it, it is necessary to increase the height of the entire equipment.

On the other hand, since the induction heating apparatus of the present invention is installed at the same level as the melting furnace and the post furnace, there are few restrictions on the layout and the height of the entire equipment can be reduced, which is advantageous.

[0021]

EXAMPLE 1 FIG. 1 shows an example of the present invention,
FIG. 1A is a vertical sectional view, and FIG. 1B is a horizontal sectional view of the bottom of the melting furnace. Waste and coke as an auxiliary material are charged into the melting furnace 1 from the charging device 2, oxygen-enriched air is blown from the tuyere 3 at the lower part of the furnace, and combustible substances in the coke and waste are burned to generate combustion heat. Therefore, the waste is sequentially preheated, dried and pyrolyzed in the melting furnace to be gasified, and then the pyrolysis residue of the waste is melted and discharged.

A post furnace 4 is provided adjacent to the melting furnace 1, and a linear communication pipe 5 is provided for connecting the bottom of the melting furnace 1 to the post furnace 4.
Two are provided. A space is provided between the two communication pipes 5, an induction heating coil 6 is provided therein, and an iron core 7 is provided in the induction heating coil 6. The iron core 7 forms a loop around the communication pipe 5.

When an alternating current is passed through the induction heating coil 6,
A magnetic flux is generated in the iron core 7, and the magnetic flux heats the molten metal by causing an induction current to flow in the molten metal loop formed in the bottom of the melting furnace, the communication pipe 5, and the post furnace 4.

The post-furnace 4 is provided with a molten slag discharge port 8 and a molten metal discharge port 9 and their installation heights are arranged higher than the bottom of the melting furnace. A storage part for the object is formed. Further, the installation height of the molten metal discharge port 9 is such that the surface level of the molten metal is the communication pipe 5.
Since it is set to be lower than the upper surface of the molten metal, the molten metal and the molten slag are constantly and stably discharged in the communication pipe 5.

Assuming that the surface level of the molten metal is 5
Above the upper surface level of the molten metal, the molten metal will fill the entire communication pipe and flow. In this situation,
The molten slag is stored in the melting furnace without being discharged, and when the weight of the stored molten slag becomes large enough to push away the molten metal, the molten metal is pushed down and discharged. After discharging, the molten slag is stopped discharging and stored again in the melting furnace. That is, although the molten slag is intermittently discharged, the molten material can be stably discharged in this embodiment.

A gas containing oxygen is blown into the molten slag from the gas blowing pipe 10. According to the present invention, since the molten metal discharge port 9 and the molten slag discharge port 8 are provided in the post-reactor 4, the molten metal separated from the specific gravity and the molten slag are discharged in a separated state, so that the mixing of the metal into the slag is prevented. This is advantageous when the slag does not rust and is effectively used as a civil engineering material. The slag produced by the method of this example was used as an aggregate or civil engineering material for secondary concrete products such as interlocking blocks.

(Embodiment 2) FIG. 2 is a cross-sectional view showing an embodiment in which a U-shaped communication pipe is provided on the bottom of a melting furnace. The same members as those shown in FIG. 1 are designated by the same reference numerals. The description is omitted. When an alternating current is passed through the induction heating coil 12, the iron core 13
A magnetic flux is generated at the bottom of the melting furnace and U
An induction current flows in the loop of the molten metal formed by the V-shaped communicating tube 11 to heat the molten metal. By providing a plurality of such heating devices, the entire furnace bottom can be maintained at a high temperature even in the case of a large melting furnace.

[0028]

According to the present invention, the following effects can be realized.

(1) When discharging slag and metal from the waste melting furnace, a slag and metal reservoir is formed at the bottom of the furnace to ensure a residence time and to completely melt the unmelted material in the slag. Can be prevented from being mixed.

(2) By providing the heating device capable of inductively heating the molten metal in the communicating portion, the water content and the calorific value of the waste fluctuate, the temperature of the molten material decreases, and the communicating pipe Can be prevented from being blocked.

(3) The specific gravity of the molten slag and the molten metal is separated in the post furnace, and the respective discharge ports are provided.
Because slag and metal can be separated and discharged,
Slag and metal are not mixed with each other and the quality of slag is good.

(4) By providing the U-shaped connecting pipe and the induction heating device, the entire furnace bottom can be maintained at a high temperature even in a large melting furnace.

(5) By blowing a gas containing oxygen into the melt stored in the post furnace, heavy metals such as lead can be converted into insoluble oxides to reduce elution.

(6) Since the induction heating device can be arranged at the same height as the bottom of the melting furnace, the height of the entire equipment can be reduced, and there are few restrictions on layout, which is advantageous.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 (a) is a vertical sectional view, and FIG. 1 (b) is a horizontal sectional view of a furnace bottom portion of a melting furnace.

FIG. 2 is a cross-sectional view showing an embodiment in which a U-shaped communication pipe is provided on the bottom of the melting furnace.

[Explanation of symbols]

1: Melting furnace 2: Charging device 3: Tuyere 4: Post furnace 5:
Communication pipe 6: Induction heating coil 7: Iron core 8: Molten slag discharge port 9: Molten metal discharge port 10: Gas injection pipe 11: Communication pipe 12: Induction heating coil 13: Iron core

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F27D 11/06 F27D 11/06 Z (72) Inventor Hideo Nishiyama 46-59 Nakahara, Tobata-ku, Kitakyushu City New Japan F term in Engineering Division, Steel Works (reference) 3K061 AA16 AB03 AC01 AC05 AC13 BA01 CA13 DA12 DB11 DB12 DB17 NB01 NB23 NB27 4K055 AA00 JA00 4K063 AA04 BA13 CA02 CA03 CA04 DA06 FA31

Claims (5)

[Claims] 1. A post-furnace for storing the melt is provided adjacent to a melting furnace for waste or incinerated ash, and the bottom of the melting furnace and the post-furnace communicate the melt through a communication pipe, In the method of discharging the molten material such that the molten slag and the molten metal are continuously discharged from the respective outlets provided in the post furnace,
At least two or more communication tubes for the melt are provided at appropriate intervals, and an induction heating device is provided between the communication tubes.
A method of discharging a waste melting furnace, characterized in that the molten metal is heated by flowing an induction current through a loop formed by the molten metal stored in the communication pipe, the melting furnace and the bottom of the post furnace. 2. A U-shaped communication pipe is provided in the metal storage portion of the furnace bottom of the melting furnace, and an induction heating device provided in the communication pipe is used.
The method for discharging a waste melt according to claim 1, wherein the molten metal at the bottom of the furnace is heated by passing an induction current through the molten metal formed in a loop shape between the communication pipe and the bottom of the melting furnace. 3. In a melt discharge device of a waste furnace or a ash melting furnace that burns the waste, a post furnace for storing the melt is provided adjacent to the melting furnace, and the melt is stored in the bottom of the melting furnace and the post furnace. Two or more linear communication pipes for communicating the melt are provided, a molten slag discharge port and a molten metal discharge port are provided in the post furnace, and an induction heating device for heating the molten metal is provided in the communication pipe. It consists of an iron core that forms a magnetic flux so that it surrounds the communication tube so that an induction current flows through the loop formed by the molten metal that is stored in the bottom of the furnace, the melting furnace, and the post furnace, and an induction heating coil that surrounds the iron core. Characteristic melt discharge device. 4. A U-shaped communication pipe is provided in the metal storage portion of the furnace bottom of the melting furnace, and the opening of the communication pipe is connected to the molten metal storage portion of the furnace bottom, and the communication pipe and the melting furnace furnace bottom. An induction heating device comprising an iron core for forming a magnetic flux so as to surround the communicating tube and an induction heating coil surrounding the iron core so that an induction current flows through the molten metal formed in a loop shape. Item 3. The waste melt discharge device according to item 3. 5. The discharge device of the waste melting furnace according to claim 3, wherein a device for blowing a gas containing oxygen is provided in the molten material storage portion of the post furnace.