JP2002115838A - Electric ash melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the outflow of unmelted ashes from a slag port. SOLUTION: An electric ash melting furnace is provided with plasma electrodes 4 and 7 for heating incinerated ashes 10 fed into the furnace chamber 6 of a plasma ash melting furnace 1 into molten slag 23. A furnace main body 2 is provided with a slag outlet 18 discharging the molten slag 23 accumulated on the hearth 5 of the furnace chamber 6 to the outside of the furnace chamber and an ash feeding port 27 feeding the incinerated ashes 10 into the inside of the furnace chamber 6, and the height of the upper edge of the ash feeding port 27 is arranged to the height lower than the lower edge of the slag port 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric ash melting furnace in which incinerated ash such as refuse is melt-processed and slag incinerated ash is recycled or reduced in amount. The present invention relates to an electric ash melting furnace for preventing ash from flowing out.

[0002]

2. Description of the Related Art Ash melting furnaces are used for reducing the volume and effective use of incinerated ash. The incinerated ash melted by the ash melting furnace is used to remove volatile substances having low boiling points, metals and other components. Slag is detoxified and recycled. The need for such incineration ash melting furnaces is increasing. These ash melting furnaces use a burner-type ash melting furnace that uses heavy oil or the like as fuel to melt incinerated ash, or an ash-melting furnace that uses electricity as a heat source, such as an electric resistance ash melting furnace or a plasma ash melting furnace. What melts is known.

FIG. 5 shows a conventional plasma arc type ash melting furnace 5.
1, the ash melting furnace 51 is provided with a furnace chamber 56 surrounded by a furnace side wall 61. The ash melting furnace 51 has a main electrode 5
4. A plasma apparatus including a furnace bottom electrode 57, a DC power supply 58, and the like is provided. The main electrode 54 is provided through the ceiling wall 53 of the melting furnace main body 52, and is supported by the elevating device 62. Thus, the furnace chamber 56 can be moved up and down. At the lower end of the main electrode 54, a furnace bottom electrode 57 is provided on a furnace bottom wall 55 facing the tip, and a DC power supply 58 for plasma generation is connected between these electrodes 54, 57. The melting furnace main body 52 has an outer wall covered with an iron shell 60, an inner wall 61 is formed of a refractory material such as brick, and an ash feeder 66 to which incineration ash 59 is supplied from a hopper 65 is provided on a peripheral wall of the melting furnace main body 52. A slag port 68, which is a discharge port for the molten slag 63, is provided.
Is connected to the drain gutter 69. A mold 71 placed on a slag conveyer 70 is provided below the tip of the slag gutter 69.

[0004] With such a configuration, incineration ash is introduced into the furnace chamber 56 of the ash melting furnace 51 from the hopper 65 for supplying incineration ash onto the furnace bottom wall 55 via the ash feeder 66, and the ash melting furnace 51 is provided. A voltage is applied between the electrodes 54 and 57 by the DC power supply 58 in a state where the furnace chamber 56 is set in a reducing atmosphere. Then, a plasma arc is generated between the electrodes 54 and 57, and the incinerated ash is heated and melted to form a slag 63, and a metal component contained in the incinerated ash is melted to become a molten metal 64 and sinks to the furnace bottom. . When the molten slag 63 accumulates at the furnace bottom and reaches the height of the slag port 68, the slag 63 overflows from the slag port 68, passes through the slag gutter 69, and is supplied to the mold 71,
The slag 63 is air-cooled while the slag conveyor 70 rotates.

[0005]

As described above, in the ash melting furnace 1 in which the molten slag 63 overflows from the slag outlet and is discharged, when the incinerated ash 59 is dropped onto the slag, the incinerated ash 59 is placed in the furnace chamber. It rises and is discharged from the slag port 68 and the gas discharge port communicating therewith. The unmelted incinerated ash 59a is not detoxified, and may emit contaminants if contained. In addition, due to fluctuations in the amount of supplied ash and changes in its properties, unmelted incinerated ash
9a may flow unmelted to the vicinity of the slag port 68 in some cases. Therefore, as shown in FIG.
When ash flows out of the slag port 68, the unmelted incinerated ash 59a may flow out together therewith. Further, in the case where the molten slag 63 is subjected to water granulation (water cooling), if the unmolten incinerated ash 59a flows into the water granulation tank along with the molten slag 63, there is a possibility that the water in the water granulation tank is contaminated. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric ash melting furnace which can prevent the outflow of unmelted incinerated ash from a slag port and the rise of incinerated ash in a furnace chamber. Aim.

[0006]

In order to achieve the above object, an electric ash melting furnace according to the present invention comprises: a melting furnace body for heating incinerated ash supplied to a furnace chamber to generate molten slag; In an electric ash melting furnace having a slag port for discharging molten slag accumulated at the furnace bottom of the furnace chamber to the outside of the furnace chamber and an ash supply port for supplying incinerated ash to the inside of the furnace chamber, the upper end of the ash supply port The height of the portion was lower than the lower end of the slag port. In the above invention, an inclined surface for guiding the incinerated ash to the furnace chamber side is formed in the supply port for supplying the incinerated ash to the furnace chamber side. Further, in the above invention, it is possible to provide a pressurizing device for pressing the incinerated ash in the ash supply port toward the furnace chamber. Further, the invention further provides that the specific gravity of the incinerated ash is a specific gravity of the molten slag and the specific gravity of the molten metal in which the metal component contained in the incinerated ash is melted. It can be supplied between the above-mentioned molten metals, and furthermore, a burner or a heater can be provided in the vicinity of the above-mentioned supply port or on the side wall of the furnace to heat the incinerated ash near the above-mentioned supply port.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electric ash melting furnace according to a first embodiment of the present invention will be described with reference to the drawings. 1 and 2 show a plasma arc type ash melting furnace 1 according to the present invention. The ash-melting furnace 1 is provided with a furnace chamber 6 surrounded by a furnace side wall 11 formed of refractory bricks. The ash-melting furnace 1 has a main electrode 4 disposed on the furnace chamber 6 side, and a furnace chamber. 6, a plasma apparatus including a furnace bottom electrode 7 disposed on the side of the furnace bottom wall 5 and a DC power supply 8 for supplying electricity thereto and the like. The main electrode 4 penetrates through the ceiling wall 3 of the melting furnace main body 2, and is configured to be able to move up and down in the furnace chamber 6 by being supported by the elevating device 15.

The main electrode 4 is made of metal or graphite, and has a cylindrical shape in which a passage for generating a plasma gas is formed. At the lower end of the main electrode 4, a furnace bottom electrode 7 is installed on a furnace bottom wall 5 facing the tip, and a DC power source 8 for plasma generation is connected between these electrodes 4 and 7. The DC power supply 8 has + connected to the furnace bottom electrode 7 side and − connected to the main electrode 4 side. On the lower wall portion of the melting furnace body 2, a slag port 18 which is a discharge port of the molten slag 23 is provided, and a slag gutter 19 is connected to the outside of the slag port 18. Immediately below the tip, a mold 20 that moves on a slag conveyor 21 is provided.

As shown in FIG. 1, a hopper 25 for receiving the incineration ash 10 is provided in the melting furnace main body 2.
An ash feeder 26 for transferring the incinerated ash 10 to the furnace chamber 6 is provided at a lower outlet of the furnace. An ash supply passage 28 extending in the vertical direction is formed at the tip of the ash feeder 26 so that the incinerated ash 10 is dropped downward. Furnace side wall 11
An ash supply port 27 for supplying the incineration ash 10 into the furnace chamber 6 is provided at a lower part of the furnace bottom wall, and a part of the furnace bottom wall 5 where molten slag and the like accumulate is located immediately below the ash supply passage 28. The ash supply port 27 is located at a lower portion of the furnace side wall 11 and is disposed on the furnace side wall 11 facing the slag port 18. The height of the ash supply port 27 is such that the position of the upper end of the ash supply port 27 is lower than the lower end of the slag port 18, that is, the position where the molten slag 23 overflows. Then, as shown in FIG. 3, the upper end of the ash supply port 27 is provided in
And an inclined surface 11 downward toward the opening of the ash supply port 27.
a is provided. The ash melting furnace 1 is provided with a control device (not shown) for controlling plasma and the like, a gas supply facility for generating plasma, and many other devices.
Detailed description thereof will be omitted.

Next, the operation of the first embodiment of the present invention will be described. As shown in FIG. 1, the incineration ash 10 is put into the furnace chamber 6 of the ash melting furnace 1 from the hopper 25 via the ash feeder 26 via the ash feeder 26 sequentially on the furnace bottom wall 5. Inclined surface 11a formed above ash supply port 27
Is inclined in a direction in which the incineration ash 10 is guided to the inside of the furnace chamber 6, thereby facilitating the supply thereof. In the furnace chamber 6 of the ash melting furnace 1, a voltage is applied between the plasma electrodes 4 and 7 by the DC power supply 8 in a state where the furnace chamber 6 is in a reducing atmosphere. Then, a plasma arc is generated between the electrodes 4 and 7, the atmosphere in the furnace chamber 6 becomes 1000 ° C. or more, the slag reaches a temperature higher than the melting point of the incinerated ash, and the melting of the incinerated ash starts.

In the incineration ash melting operation, the incineration ash is heated and melted by the heat of the plasma arc to become a molten slag 23, and similarly, the metal component contained in the incineration ash is melted to become a molten metal 24, and a specific gravity is obtained. The light slag 23 rises to the upper part, and the metal 24, which has a higher specific gravity,
Sink at the bottom of 3. Slag 23 accumulates in the furnace bottom and slag port 18
Is reached, the slag 23 overflows from the slag port 18, passes through the slag gutter 19, is supplied to the mold 20 provided on the slag conveyor 21, and the slag 23 is cooled. When the molten slag 23 overflows from the slag port 18, the height of the ash supply port 27 is
8 is lower than the height of the molten slag 23.
Becomes higher than the height of the ash supply port 27, and the incinerated ash 10 is supplied into the molten slag 23. Thereby, the incineration ash 10 is prevented from rising into the furnace chamber 6, and even if the incineration ash 10 floats on the slag 23, the incineration ash is prevented from rising into the furnace chamber 6 by wetting. You. Also, if the bulk density of the incinerated ash 10 is increased in advance and the weight is set between the molten slag 23 and the molten metal 24, the incinerated ash 10 does not float on the surface of the molten slag 23, and Incineration ash 10
Is supplied.

Next, an electric ash melting furnace according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 4, an ash supply passage 28 connected to the hopper and the ash feeder is provided vertically along the furnace side wall 11. In the lower part of the ash supply passage 28, the incinerated ash 10 is
An ash supply port 27 for supplying into the inside is provided. The ash supply port 27 is located at a lower part of the furnace side wall 11 and is arranged to face the slag port. The height of the ash supply port 27 is such that the position of the upper end of the ash supply port 27 is lower than the lower end of the slag port, that is, the height of the discharge section of the molten slag 23. The part is provided with a downwardly inclined surface 11 a inward of the furnace chamber 6. Further, the ash melting furnace 1 is provided with an incineration ash extrusion piston 30 which reciprocates vertically in the upper wall of the ash supply passage 28 of the ash supply port 27. The extrusion piston 30 can operate the extrusion piston 30 by hydraulic or mechanical drive. According to the present embodiment, there is an effect that the incineration ash 10 can be smoothly supplied to the furnace chamber 6 side by operating the extrusion piston 30. In addition, all the effects of the above embodiment are provided. I have.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention. For example, in the above embodiment, a plasma type ash melting furnace is described as an example, but another electric ash melting furnace of a resistance type may be used, and the present invention can be applied to an electric ash melting furnace. . In addition, by supplying the incineration ash 10, the molten slag 23
Etc. are prevented from being cooled by the incineration ash 10,
A heater or a burner for heating incinerated ash or the like may be provided near the ash supply port 27 or on the furnace side wall 11.

[0014]

As described above, according to the electric ash melting furnace of the present invention, the melting furnace main body for heating the incinerated ash supplied to the furnace chamber to generate molten slag, and the furnace in the furnace chamber In an electric ash melting furnace having a slag port for discharging molten slag accumulated at the bottom to the outside of the furnace chamber and an ash supply port for supplying incinerated ash to the inside of the furnace chamber, the height of the upper end of the ash supply port Is disposed at a position lower than the lower end of the slag port, so that the incinerated ash is prevented from rising into the furnace chamber and discharged to the outside of the furnace together with the exhaust gas, and the unmelted incinerated ash is discharged to the outside of the furnace chamber. When the molten slag is subjected to granulation treatment, contamination of granulated water can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a plasma arc ash melting furnace according to a first embodiment of the present invention.

FIG. 2 is a horizontal sectional view of the plasma arc ash melting furnace of FIG. 1;

FIG. 3 is an enlarged sectional view of the vicinity of an ash supply port of the plasma arc ash melting furnace of FIG. 1;

FIG. 4 is an enlarged sectional view near an ash supply port of a plasma arc ash melting furnace according to a second embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional plasma arc ash melting furnace.

FIG. 6 is a horizontal sectional view of the plasma arc ash melting furnace of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma arc type ash melting furnace 2 Melting furnace main body 3 Ceiling wall 4 Main electrode 5 Furnace bottom wall 6 Furnace room 7 Furnace bottom electrode 8 DC power supply 11 Furnace side wall 15 Elevating device 18 Slag outlet 19 Slag gutter 23 Melting slag 24 Metal 25 hopper 26 ash feeder 27 ash supply port 28 ash supply passage 30 extrusion piston

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Keita Inoue 12 Nishikicho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Heavy Industries, Ltd. Yokohama Works F-term (reference) 3K061 AA18 AB03 AC03 CA01 CA14 DB04 DB06 DB20 NB02 NB03 NB13 NB16 NB27 4K045 AA04 BA07 BA10 RA01 RC08

Claims (5)

[Claims] 1. A melting furnace body for heating incineration ash supplied to a furnace chamber to generate molten slag, a slag port for discharging molten slag accumulated in a furnace bottom of the furnace chamber to the outside of the furnace chamber, In an electric ash melting furnace having an ash supply port for supplying incineration ash to the inside of the furnace chamber, the height of the upper end of the ash supply port is arranged at a position lower than the lower end of the slag port. Electric ash melting furnace. 2. The electric ash according to claim 1, wherein an inclined surface for guiding the incinerated ash to the furnace chamber is formed in the supply port for supplying the incinerated ash to the furnace chamber. Melting furnace. 3. The electric ash melting furnace according to claim 1, further comprising a pressurizing device for pressing the incinerated ash in the ash supply port toward the furnace chamber. 4. A specific gravity of the incinerated ash is defined as a weight between a specific gravity of the molten slag and a specific gravity of a molten metal in which a metal component contained in the incinerated ash is melted. The electric ash melting furnace according to any one of claims 1 to 3, wherein the furnace is supplied between the molten metals. 5. The electric power generator according to claim 1, wherein a burner or a heater is provided near the supply port or on a side wall of the furnace to heat the incinerated ash near the supply port. Ash melting furnace.