JPH10185163A - Melting furnace capable of separating and extracting molten salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melting furnace capable of separating the molten salt in which any components of the furnace are not corroded by the composition of the molten stuff. SOLUTION: In a melting furnace, electrodes 3 are arranged in a furnace tank 1 from an upper part, and the burnt ash is melted by the current flowing between the electrodes 3 through the molten slag 14 in the furnace tank 1. The furnace is divided into a main chamber 4 for melting the main ash in which the electrodes 3 are arranged, and a sub chamber 5 for melting the fly ash adjacent to the main chamber 4 by providing a bulkhead 2 in the furnace tank 1, a communication part 6 to communicate the main chamber 4 with the sub chamber 5 is formed in the bulkhead 2, a molten metal discharge part 9 is provided on a lower part of a side wall 8 in the main chamber 4, a molten slag discharge part 10 is provided on an upper part of the side wall 8, and a molten salt discharge part 11 is provided on an upper part of the side wall 8 above the communication part 6 in the sub chamber 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melting furnace for melting and processing incinerated ash generated in an incinerator. To a melting furnace that melts incineration ash by a current flowing between electrodes.

[0002]

2. Description of the Related Art The incineration ash introduced into a melting furnace of this type contains main ash and fly ash (dust contained in exhaust gas generated in the incinerator). Of these, the main ash becomes molten slag and molten metal when melted. On the other hand, when fly ash is melted, it becomes a molten salt mainly composed of salts such as NaCl and CaCl ₂ .

[0003] These melts are a molten metal, a molten slag, and a molten salt in order of decreasing specific gravity.

[0004] Therefore, if the furnace tank has a single chamber as in a conventional melting furnace (not shown), the molten material is composed of molten metal at the furnace bottom, molten slag on the molten metal, and molten salt on the molten metal. Thus, the layers are formed separately.

In an electric resistance type melting furnace, a plurality of electrodes are charged into a furnace tank, immersed in the molten slag, and electricity is supplied between the electrodes through the molten slag to transfer Joule heat to the molten slag. To be generated.

However, since the molten salt and the molten slag form a vertical layer in the furnace tank, the electrode is immersed in the molten slag and penetrates the molten salt at the same time. Molten salt has much higher conductivity than molten slag. Therefore, between the plurality of electrodes, electricity is short-circuited and flows through the molten salt layer instead of the molten slag (electric power is concentrated on the molten salt). Therefore, the molten slag is not heated to the predetermined temperature, but becomes high in viscosity, and as a result, smooth discharge is hindered. This does not allow smooth operation of the melting furnace.

Therefore, in order to address this problem,
A melting furnace having a structure as disclosed in JP-A-7-77319 has been proposed and is known.

[0010] Referring to FIG. 2, this melting furnace is provided with a partition 52 in a furnace tank 51 between a plurality of electrodes 53. The partition wall 52 is provided so as to partition the upper part in the furnace tank 51. The partition wall 52 is for preventing a short circuit between the plurality of electrodes 53 via the layer of the molten salt 66. Therefore, the partition 5
2 must be made of a non-conductive material such as a refractory material.

On the other hand, since the gap 56 is formed between the lower end of the partition wall 52 and the furnace bottom 57, the molten slag 64 can flow freely between one side and the other side of the partition wall 52. It has become.

In FIG. 2, reference numeral 61 denotes a molten salt discharge portion, reference numeral 60 denotes a molten slag discharge portion, reference numeral 67 denotes an incineration ash input portion, reference numeral 68 denotes an exhaust gas portion, and reference numeral 69 denotes an incineration ash.

The incineration ash 69 introduced into the furnace from the incineration ash introduction section 67 is melted, and the molten salt 66 and the molten slag 6
It becomes 4. The molten salt 66 is separated from the molten salt discharge part 61 and taken out. The molten slag 64 is discharged from the molten slag discharge unit 60.

[0012]

However, in the melting furnace described in Japanese Patent Application Laid-Open No. 7-77319, the following problems occur because the partition walls 52 are made of a non-conductive material.

The molten salt 66 and the molten slag 64 contain N
Contains highly aggressive components such as a, K, and SiO ₂ . However, it is a non-conductive material, and Na,
None have strong corrosion resistance to K, SiO _{2 and the} like. Therefore, there arises a problem that the partition walls are eroded.

The present invention has been made to solve such a problem of the conventional example.

An object of the present invention is to provide a melting furnace capable of separating a molten salt in which the partition walls are not corroded by the components of the melt.

[0016]

In order to achieve the above-mentioned object, the present invention is directed to an incinerator ash, in which an electrode is inserted from above in a furnace tank and electric current flows between the electrodes through a molten slag of the furnace tank. In a melting furnace for melting, by providing a partition in the furnace tank, the electrode is divided into a main chamber for melting main ash and a sub-chamber adjacent to the main chamber for melting fly ash. The main chamber has a communicating part for communicating the sub-chamber with the main chamber. The main chamber is provided with a molten metal discharging part at a lower part of the side wall, a molten slag discharging part is provided at an upper part of the side wall, and the sub-chamber is located above the communicating part. And a molten salt discharge portion is provided at the upper part of the side wall.

That is, in the present invention, the partition separates the main chamber for melting the main ash, in which the electrodes are arranged, and the sub-chamber for melting the fly ash. It is not intended to provide a partition between the electrodes and to prevent electricity from flowing between the electrodes via the molten salt. That is, the partition walls of the present invention need not be made of a non-conductive material, but can be made of a conductive material. If a conductive material such as carbon is used as the material of the partition, Na, K, Si
It has sufficient corrosion resistance to O _{2 and the} like.

Further, since the molten slag and the molten metal in the main chamber flow into the sub-chamber through the communicating portion of the partition wall, and the fly ash is melted by the heat, the electrode and other heat sources are unnecessary in the sub-chamber.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an embodiment of a melting furnace of the present invention capable of separating and extracting a molten salt.

In this melting furnace, a partition 2 is provided in a furnace tank 1 so that a main chamber 4 in which an electrode 3 is disposed for melting main ash and a main chamber 4 adjacent to the main chamber 4 for melting fly ash. The main chamber 4 and the sub-chamber 5 are separated from each other, and the partition 2 is formed with a communication portion 6 for communicating the main chamber 4 and the sub-chamber 5.

Here, in the present embodiment, the partition wall 2 is provided so as to extend until the lower end is attached to the furnace bottom 7 and partition the inside of the furnace tank 1. In the present embodiment, the communication portion 6 is formed by forming a plurality of round holes in the partition wall 2.

In the present invention, the partition wall 2 separates the main chamber 4 and the sub chamber 5 from each other, and does not partition between the plurality of electrodes 3. In the present invention, all the electrodes 3 are provided in the main chamber 4. That is, in the present invention, the partition 2
Is not required to have a current interrupting function, and may be made of a non-conductive material. Since the partition 2 can be made of a conductive material, if carbon is used as the conductive material, for example, the partition 2 will have sufficient erosion resistance to molten salts, Na, K, SiO _{2 and the} like contained in the molten slag. It will have the nature.

The main ash is supplied to the main chamber 4 and the fly ash is supplied to the sub-chamber 5. Among the incinerated ash generated in the incinerator (not shown), the ratio of the amount of fly ash is smaller than the amount of main ash. In accordance with this quantitative ratio, the partition walls 2 are arranged such that the volume of the sub-chamber 5 becomes smaller than the volume of the main chamber 4.
Is set.

The main chamber 4 is provided with a molten metal discharge section 9 below the side wall 8 and a molten slag discharge section 10 above the side wall 8. The electrode 3 can be driven up and down by a drive mechanism (not shown). The electrode 3 is connected to a power supply (not shown).

On the other hand, the sub-chamber 5 is configured such that a molten salt discharge section 11 is provided above the side wall 8 at a position higher than the communication section 6 (the uppermost one of the holes of the communication section 6). The reason why the molten salt discharge unit 11 is provided at a position higher than the communication unit 6 is as follows.
This is to prevent the molten salt 16 in the sub chamber 5 from flowing into the main chamber 4 through the communication portion 6.

Further, the molten slag and the molten metal in the main chamber 4 flow into the sub-chamber 5 through the communicating portion 6 of the partition 2 and melt the fly ash by the heat. No heat source is required.

According to the melting furnace configured as described above, the molten slag 14 is smoothly discharged by sufficiently heating the molten slag 14 as follows.

The main ash 12 is charged into the main chamber 4 and the fly ash 13 is charged into the sub-chamber 5.

In the main chamber 4, the electrode 3 is lowered and immersed in the molten slag 14. Since the fly ash 13 does not exist in the main chamber 4, the plurality of electrodes 3 are not electrically short-circuited via the fly ash 13. That is, the electrode 3
Electricity is reliably supplied through the molten slag 14. for that reason,
The molten slag 14 is heated to a predetermined temperature or higher by the Joule heat, and as a result, the viscosity is reduced to a predetermined level or less, so that the molten slag 14 is smoothly discharged from the molten slag discharge unit 10.
The molten slag 14 is usually continuously discharged during the operation of the melting furnace.

In the main chamber 4, the molten material of the main ash 12 is separated from the molten metal 15 on the furnace bottom 7 by the specific gravity difference.
To form a layer. During the operation of the melting furnace, the molten metal 15 is intermittently discharged from the molten metal discharge section 9, that is, discharged outside the furnace when a predetermined amount or more is deposited.

The molten slag 14 and the molten metal 15 in the main chamber 4 flow into the sub-chamber 5 through the communicating portion 6 formed in the partition 2. In the sub-chamber 5, the molten metal 1
Fly ash 13 is melted by the heat of 5 and molten slag 14 to form molten salt 16. And this molten salt 16
Is discharged from the molten salt discharge section 11 to the outside of the furnace. Molten salt 1
6 has a lower specific gravity than the molten slag 14, so that it does not flow into the main chamber 4 through the communication portion 6. Therefore, a short circuit between the electrodes 3 via the molten salt 16 can be reliably prevented.

As described above, the molten slag 14 and the molten metal 15 in the main chamber 4 flow into the sub-chamber 5 through the communicating portion 6 of the partition 2 and melt the fly ash 13 by the heat. No electrodes or other heat sources are required.

Since the partition 2 is made of a conductive material, for example, carbon, it is not eroded by the Na, K, SiO _{2 and the} like contained in the molten salt 16 and the molten slag 14.

[0035]

As described above, according to the melting furnace capable of separating molten salt according to the present invention, the main chamber for melting the main ash and the sub-chamber for melting the fly ash in which the electrodes are arranged are provided. It is divided by a partition, and a partition is provided between a plurality of electrodes, and it is not intended to prevent electricity from flowing between the electrodes via a molten salt. Therefore, the partition does not need to be made of a non-conductive material, and can be made of a conductive material. Therefore, if a conductive material such as carbon is used as a material for the partition, the partition has sufficient erosion resistance to Na, K, SiO _2, etc., thereby improving the durability of the melting furnace. Life can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing one embodiment of a melting furnace capable of separating a molten salt according to the present invention.

FIG. 2 is a schematic longitudinal sectional view showing an example of a conventional melting furnace capable of separating molten salt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace tank 2 Partition wall 3 Electrode 4 Main room 5 Sub chamber 6 Communication part 8 Side wall 9 Molten metal discharge part 10 Molten slag discharge part 11 Molten salt discharge part 12 Main ash 13 Fly ash 14 Molten slag 15 Molten metal 16 Molten salt

Claims (1)

[Claims] In a melting furnace in which electrodes are inserted from above in a furnace tank and incineration ash is melted by a current flowing between the electrodes through a molten slag of the furnace tank, a partition is provided in the furnace tank. A main chamber for melting the main ash in which the electrodes are arranged, and a sub-chamber adjacent to the main chamber for melting the fly ash, and forming a communication portion for communicating the main chamber and the sub-chamber with the partition wall. The main chamber is provided with a molten metal discharge portion at the lower portion of the side wall, the molten slag discharge portion is provided at the upper portion of the side wall, and the sub chamber is provided with a molten salt discharge portion at the upper portion of the side wall at a position higher than the communication portion. Melting furnace that can separate and extract molten salt.