JPH11270834A - Ash melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower equipment costs and make the process compact by removing dioxin being thermally decomposed in an ash melting furnace to abolish an exhaust gas treating device. SOLUTION: This ash melting furnace 1 performs a treatment of melting fly ash and incineration ash. The ash melting furnace 1 is built up with two chambers. One is an ash melting chamber 2 having an ash feeding port 3 at an upper part thereof defined by a partition wall 6 so arranged to hang from a top part of the ash melting furnace 1 for the formation of a communication path 8 at a lower end part thereof, and the other is an auxiliary heating chamber 5 which has a slag discharge port 4 so arranged at an intermediate part thereof to remove a molten slag 14 causing an overflow thereof while discharging an exhaust gas 24. Also in the ash melting chamber 2, a main electrode 9 is installed at an upper part thereof and a furnace bottom electrode 10 at the bottom part thereof vertically facing each other and in the auxiliary heating chamber 5, an auxiliary electrode 11 is installed at an upper part thereof and a furnace bottom electrode 12 at the bottom part thereof vertically facing each other. A communication hole 6a is provided at an upper part of the partition wall 6 while an exhaust gas supply pipe 7 is installed on the side of the auxiliary heating chamber 5 of the communication hole 6a with the lower end thereof in proximity to the top surface of the molten stag 14a. An exhaust gas discharge pipe 17 is provided being vertically opened surrounding the slag removing port 4 from outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ash melting furnace for melting and solidifying fly ash and incinerated ash generated when municipal solid waste and industrial waste are incinerated, and more particularly to an ash melting furnace that decomposes dioxin in exhaust gas to be effective. The present invention relates to an ash melting furnace for treating ash.

[0002]

2. Description of the Related Art Waste such as municipal solid waste and sewage sludge has been incinerated in an incineration facility, and the resulting incinerated ash and dust (fly ash) have conventionally been disposed of in landfills. However, due to the problem of depletion of landfill sites and the problem of groundwater contamination due to elution of harmful heavy metals, the necessity of volume reduction, harmlessness and recycling by melting is increasing.

[0003] Against this background, carbon residue in incineration ash,
An ash melting furnace for melting and processing incinerated ash discharged from an incinerator using coke, kerosene and electric power as a heat source has been proposed, and some of the ash melting furnaces are actually treated. Among these, there are a plasma arc heating method and an electric resistance heating method as ash melting furnaces using electric power as a heat source.

FIG. 2 is a longitudinal sectional view of a conventional ash melting furnace.
In the figure, a is an ash melting furnace. b is an ash melting chamber. c is a slag outlet provided in the middle of the ash melting furnace a, and d is a molten metal outlet provided at the bottom of the ash melting furnace a. e
Is a main electrode, and f is a furnace bottom electrode. m is a power supply for flowing DC electricity between the main electrode e and the furnace bottom electrode f, and n and o are the electric wires. g denotes an ash input port provided at the top of the ash melting furnace a, into which fly ash and incinerated ash carried by a not-shown conveyor or the like are fed into the ash melting furnace a. h is the ash melting furnace a
It is an exhaust gas outlet provided at the top of the. i is an ash solid layer such as fly ash or incinerated ash charged into the ash melting chamber b, and j is molten slag. k is a metal layer.

[0005]

In the above ash melting furnace, when fly ash or incinerated ash is introduced into the ash melting chamber, part of the dioxin adhering to the fly ash or incinerated ash is decomposed by thermal decomposition. Before the gas reached the ash-melting furnace and was discharged out of the furnace together with the exhaust gas, an exhaust gas treatment device was provided downstream of the exhaust gas outlet of the ash melting furnace to remove the discharged dioxin. Therefore, equipment for removing dioxin is required, and there are problems such as an increase in equipment cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and eliminates an exhaust gas treatment apparatus by thermally decomposing and removing dioxin in an ash melting furnace to reduce equipment costs. It is another object of the present invention to provide an ash melting furnace capable of achieving a compact process.

[0007]

According to the present invention, there is provided an ash melting furnace for melting and processing fly ash and incinerated ash, wherein the ash melting furnace is provided from the top of the ash melting furnace. At the same time as the ash melting chamber having an ash inlet at the top by a partition wall provided so as to form a communication path at the lower end by suspending, and molten slag is overflowed to the middle part to discharge ash, The ash melting chamber has a main electrode at the top and a bottom electrode at the bottom so as to face up and down. The chamber is provided with an auxiliary electrode at the top and a furnace bottom electrode at the bottom so as to face up and down, a communication hole is provided at the top of the partition wall, and a lower end is provided on the auxiliary heating chamber side of the communication hole. An exhaust gas supply pipe arranged close to the upper surface of the molten slag is provided, and the slag port is surrounded from the outside. Ash melting furnace provided with an exhaust gas discharge pipe having an open top and bottom is provided.

Next, the operation of the present invention will be described. The ash melting furnace is composed of two chambers, an ash melting chamber and an auxiliary heating chamber. Fly ash and incinerated ash introduced into the ash melting chamber are first heated in a large ash melting chamber by a main electrode and a furnace bottom electrode arranged in the ash melting chamber to form molten slag. Here, the ash is separated into a lower molten slag layer and an ash solid layer floating above it. Further, this molten slag is melted at a high temperature of 1,200 ° C. to 1,600 ° C. The molten slag flows into the small auxiliary heating chamber through the communication passage below the partition wall, and the exhaust gas is sent to the upper surface of the molten slag of the auxiliary heating chamber through the exhaust gas supply pipe provided in the communication hole above the partition wall. At this time, dioxin that has adhered to fly ash or incineration ash and released from the ash before reaching the thermal decomposition temperature is sent together with the exhaust gas to the upper surface of the molten slag in the auxiliary heating chamber through the exhaust gas supply pipe and melted. Decomposes thermally due to high temperature of slag. In addition, the auxiliary heating chamber lowers the viscosity by raising the temperature of the molten slag by energizing the auxiliary electrode,
It is provided to smoothly discharge the molten slag from the slag outlet. The molten slag and the exhaust gas are discharged from a slag port serving also as an exhaust gas discharge port, and the molten slag is discharged downward in an exhaust gas discharge pipe surrounding the slag port from the outside, and the exhaust gas is discharged upward. Exhaust gas is mixed with air sucked from below through an exhaust gas exhaust pipe whose top and bottom are open, quenched and discharged, so that dioxin is not resynthesized. Therefore, the exhaust gas treatment device for removing dioxin on the downstream side of the ash melting furnace can be abolished, and equipment costs can be reduced and the process can be made more compact.

[0009]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of the present invention, and is a longitudinal sectional view of an ash melting furnace according to the present invention. In FIG. 1, reference numeral 1 denotes an ash melting furnace for melting and processing fly ash and incineration ash, and a partition wall 6 suspended from the top of the ash melting furnace 1.
Ash melting chamber 2 having an ash inlet 3 at the top, and an auxiliary heating chamber 5 having a slag outlet 4 at the middle for overflowing and discharging the molten slag 14a. ing.
The slag port 4 also serves as an exhaust gas outlet (exhaust port) for discharging an exhaust gas 24 containing a gas generated by heating the ash solid layer 13 in the ash melting chamber 2 and a gas generated from the molten slag 14. . 6a is a communication hole provided in the upper part of the partition wall 6.
Reference numeral 7 denotes an exhaust gas supply pipe 7 arranged on the auxiliary heating chamber 5 side of the communication hole 6a such that the lower end is close to the upper surface of the molten slag 14a. The exhaust gas generated in the ash melting chamber 2 is supplied to the upper surface of the molten slag 14 a of the auxiliary heating chamber 5 through the exhaust gas supply pipe 7. In addition, dioxin adhering to the ash and released from the ash before reaching the thermal decomposition temperature is exhaust gas 24
At the same time, it is fed to the upper surface of the molten slag 14 a of the auxiliary heating chamber through the exhaust gas supply pipe 7 and discharged from the slag port 4. Reference numeral 8 denotes a communication passage provided below the partition wall 6 so as to communicate the ash melting chamber 2 and the lower part of the auxiliary heating chamber 5.
The molten slag 14 melted inside flows into the auxiliary heating chamber 5 through the communication passage 8. 14a is the molten slag flowing into the auxiliary heating chamber 5, and 14b is the molten slag discharged from the slag port 4. 9 is a main electrode provided so as to penetrate the top of the ash melting chamber 2, and 10 is an ash melting furnace 1.
Is a furnace bottom electrode buried under the bottom of the main electrode 9 so as to face the main electrode 9 up and down. Reference numeral 18 denotes a power supply for applying a direct current to the main electrode 9 and the furnace bottom electrode 10, and reference numerals 19 and 20 denote electric wires. Reference numeral 11 denotes an auxiliary electrode provided to penetrate the top of the auxiliary heating chamber 5, and reference numeral 12 denotes a furnace bottom electrode buried in the bottom of the ash melting furnace 1 so as to face the main electrode 11 up and down.
Reference numeral 21 denotes a power supply for supplying a direct current to the auxiliary electrode 11 and the furnace bottom electrode 12, and reference numerals 22 and 23 denote electric wires thereof. When the exhaust gas 24 is supplied from the exhaust gas supply pipe 7 to the upper surface of the molten slag 14a, the temperature of the upper surface of the molten slag 14a decreases. Is preferred. Reference numeral 17 denotes an exhaust gas discharge pipe which surrounds the slag outlet 4 from the outside and is opened up and down.

Reference numeral 13 denotes a solid ash layer, such as fly ash or incinerated ash, which has been introduced into the ash melting chamber 2;
4 above. 15 is molten slag 1
4 is a metal layer separated from the metal layer 4 and accumulated at the bottom of the ash melting chamber 2. The metal layer 15 generates an arc between itself and the main electrode 8 at an appropriate time to melt the metal, and then discharge the metal through the metal discharge port 16 to the outside. The reason why the slag port 4 is provided in the middle of the ash melting furnace 1 is to overflow the slag melting furnace 1 and keep the level of the molten slag layer 13 constant.

Next, the operation of the embodiment of the present invention will be described. The ash melting furnace 1 includes two ash melting chambers 2 and an auxiliary heating chamber 5. Fly ash and incinerated ash introduced into the ash melting chamber 2
First, in the large ash melting chamber 2, the molten slag 14 is heated by the main electrode 9 and the furnace bottom electrode 10 arranged in the ash melting chamber 2. Here, the ash is separated into a lower molten slag layer 14 and an ash solid layer 13 floating thereon. Further, the molten slag 14 is melted at a high temperature of 1,200 ° C. to 1,600 ° C. The molten slag 14 flows into the small auxiliary heating chamber 5 through the communication passage 8 below the partition wall 6, and the exhaust gas 24 passes through the exhaust gas supply pipe 7 provided in the communication hole 6 a above the partition wall 6, and It is fed to the upper surface of the molten slag 14a. At this time, dioxin adhering to fly ash or incineration ash and detached from the ash before reaching the pyrolysis temperature is exhaust gas 24
At the same time, it is fed to the upper surface of the molten slag 14a of the auxiliary heating chamber 5 through the exhaust gas supply pipe 7, and is thermally decomposed by the high temperature of the molten slag 14a. The auxiliary heating chamber 5 is provided with an auxiliary electrode 11
When the molten slag 14a is heated, the temperature is raised to lower the viscosity, and the molten slag 14a is discharged from the slag port 4 smoothly. The molten slag 14a and the exhaust gas 24 are discharged from the slag port 4 also serving as the exhaust gas discharge port, and the molten slag 14b is discharged downward in the exhaust gas discharge pipe 17 surrounding the slag port 4 from the outside, and the exhaust gas 24a is discharged upward. Is done. Exhaust gas 24a is an exhaust gas exhaust pipe 1 whose top and bottom are open
Since it is mixed with the air sucked from below in step 7 and rapidly cooled and discharged, there is no risk of dioxin being resynthesized. Therefore, an exhaust gas treatment device for removing dioxin on the downstream side of the ash melting furnace 1 can be eliminated, and equipment costs can be reduced and the process can be made more compact.

The present invention is not limited to the above embodiment. For example, the present invention may be applied to a case where the furnace bottom electrode is not divided into a main electrode and an auxiliary electrode but may be an integral furnace bottom electrode. Of course, various changes can be made without departing from the spirit of the invention.

[0013]

As described above, according to the present invention, dioxin is thermally decomposed in an ash melting furnace, so that an exhaust gas treatment device can be abolished, equipment costs can be reduced, and the process can be made more compact. It has excellent effects.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an ash melting furnace according to the present invention.

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

[Description of Signs] 1 Ash melting furnace 2 Ash melting chamber 3 Ash inlet 4 Slag outlet 5 Auxiliary heating chamber 6 Partition wall 6a Communication hole 7 Exhaust gas supply pipe 8 Communication path 9 Main electrode 10, 12 Furnace bottom electrode 11 Auxiliary electrode 13 Ash solid layer 14, 14a, 14b Molten slag 15 Molten metal 16 Metal outlet 17 Exhaust gas exhaust pipe 24, 24a Exhaust gas

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shun-ichiro Ueno 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Pref. Ishikawajima Harima Heavy Industries, Ltd. (72) Inventor Toshiyuki Suzuki 2-1-1 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] An ash melting furnace for melting fly ash and incinerated ash, wherein the ash melting furnace is suspended from a top of the ash melting furnace and provided with a communication passage at a lower end thereof. It is composed of two chambers, an ash melting chamber having an ash inlet at the top by a wall, and an auxiliary heating chamber having a slag outlet for discharging the exhaust gas at the same time as the molten slag is overflowed in the middle to discharge the slag. The ash melting chamber has a main electrode at the top and a bottom electrode at the bottom so as to face vertically, and the auxiliary heating chamber has an auxiliary electrode at the top and the bottom electrode at the bottom vertically. An exhaust gas supply pipe is provided so that a communication hole is provided at the upper part of the partition wall, and an auxiliary heating chamber side of the communication hole has a lower end close to the upper surface of the molten slag. An ash melting pipe provided with an exhaust gas exhaust pipe surrounding the slag outlet from the outside and opening up and down. Melting furnace.