JPH07253207A - Method of fusing ash of incineration and device therefor - Google Patents

Abstract

PURPOSE:To permit the regulation of gas atmosphere in a furnace, the restraint of contact between the inner wall of a furnace body and a heat generating body, the restraint of the consumption of the heat generating body and the elongation of the life of refractories for the inner wall remarkably. CONSTITUTION:A device is constituted of the furnace body 1 of an electromagnetic induction heating furnace, a lid 2 for closing the upper part of the furnace body 1, a slag hole 4 connected to the lower part of the furnace body and a n induction coil 3 wound' around the outer periphery of the furnace body while heat generating bodies 5 are stacked and arranged in the furnace. The heat generating bodies 5 are formed by stacking the pillar type or spherically formed heat resistant conductive materials such as graphite, conductive ceramic and the like regularly or irregularly. A gas introducing tube 6 is connected to the lid 2 and is inserted into the furnace. The gas introducing tube 6 is for supplying gas into the furnace while an inert gas, such as nitrogen, helium, argon or the like, or a reducing gas containing no oxygen or the like is optimum for the gas supplied into the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melting treatment method and an apparatus therefor for reducing the volume of solidified incineration ash produced by incinerating municipal waste, sewage sludge and other waste, and detoxifying it, The present invention relates to a treatment method and apparatus suitable for continuous and stable melting of incinerated ash.

[0002]

2. Description of the Related Art Municipal solid waste (garbage) is disposed of in landfill, but recently, it is disposed of after incineration because of difficulty in securing landfill. However, although the volume of waste can be reduced to about 1/10 by incineration, it is still a problem to secure landfill sites, disperse ash, elute from ash and recontaminate the environment with unburned materials. is there.

Therefore, a means for preserving the environment has been proposed, in which the incinerated ash is melt-processed to further reduce the volume, and the incinerated ash is solidified into glass to confine heavy metals.

The incineration ash can be melted by a burner combustion heating method utilizing combustion heat (JP-A-3-263513), a plasma heating method (JP-A-63-101360), or an arc discharge heating method (JP-A-2). -99184). Further, an electromagnetic induction heating method (Japanese Patent Laid-Open No. 61-210998) is known.

[0005]

In the above-mentioned conventional melting method and apparatus, a large amount of waste gas is discharged by combustion with fuel and an auxiliary combustion material (air) and the load of the gas treatment is increased, and the arc is generated. The discharge heating method and the like have a drawback in that the molten iron needs to be pooled as a heat source for melting the ash, which is structurally complicated, and that the arc electrode is consumed greatly.

Further, in the electromagnetic induction heating system, it is not always necessary to pool the molten iron. In that case, a heating element made of graphite or carbon material is placed in the magnetic field generated by the induction coil, and the generated heat melts the ash. Therefore, the ash and the heating element are contacted with each other to be melted, and the presence of oxygen in the furnace may oxidize and exhaust the heating element. Further, the heating element is also in contact with the refractory material on the inner wall of the furnace, which may cause wear and damage to the inner wall of the furnace due to electric sparks or the like.

An object of the present invention is, in an electromagnetic induction heating system, first of all, to prevent consumption of a heating element during melting treatment of a heating element such as graphite which is laminated in a furnace. Secondly, Improving the contact between the inner wall of the furnace and the heating element to prevent mutual wear and damage of the inner wall of the furnace and the heating element. Thirdly, the atmosphere inside the furnace can be adjusted to withstand long-term use and to be stable. It is an object of the present invention to provide a processing method and an apparatus that enable molten slag to be discharged.

[0008]

[Means for Solving the Problems] In a case where a conductive heating element such as graphite is laminated in an electromagnetic induction heating furnace and the heating element is induction-heated to melt incineration ash, it enters the furnace. The heating element is easily oxidatively consumed by air or oxygen generated when the incineration ash is melted. That is, the heating element (main component of carbon C) during heating is C + O ₂ = CO ₂ due to the presence of a large amount of oxygen in the furnace.
Cause a reaction.

The heating element is consumed and needs to be replaced frequently. In view of this, means for introducing gas into the furnace is provided, and the periphery of the heating element is adjusted to the gas atmosphere. This gas is preferably an inert gas such as nitrogen, carbon dioxide, helium, or argon, or a reducing gas containing no oxygen, for example, a combustion gas generated during incineration. Further, the inner wall of the electromagnetic induction heating furnace is composed of a refractory material formed in a vertical direction in a concavo-convex shape, and a heat-resistant conductive material such as graphite or conductive ceramics is laminated on a heating element formed in a columnar shape or a spherical shape. , To reduce the collision between the inner wall and the heating element. A means for introducing the inert gas through a gas introduction pipe is provided at the stacking position. Further, it is provided with a means for exhausting the introduced inert gas and the like and the gas emitted when the incineration ash is melted from the upper part of the heating furnace and the lower part of the heating furnace.
The upper part of the heating furnace is provided with an upper exhaust port, the lower part is provided with a lower exhaust port on a protective wall which surrounds and connects the outlet, and suctions through the outlet. The molten slag drops downward from the outlet and is cooled with water or air to be solidified.

[0010]

[Function] The incineration ash charged into the electromagnetic induction heating furnace flows down while being melted between the layers of the conductive heating element such as graphite which is formed into a columnar shape or a spherical shape, but the active gas such as oxygen is introduced. Since it is quickly replaced with the inert gas or the reducing gas, the oxidative consumption of the heating element is suppressed. Therefore, the inert gas is chemically stable nitrogen, helium, argon, etc.
Alternatively, the reducing gas is preferably a combustion gas generated in an incinerator or the like. Then, unnecessary gas can be removed by means of exhausting gas from the upper part of the heating furnace and the lower part of the heating furnace, and the gas does not remain in the furnace. Furthermore, by forming the inner wall in an uneven shape in the vertical direction, the incinerated ash injected fills the recesses, reducing direct contact between the heating element and the wall surface, and suppressing wear and tear on the wall surface due to electrical sparks, etc. Not only can this be done, but the consumption of the heating element can also be suppressed.

Further, since such high-temperature gas can be taken out together with the molten slag from the slag port at the bottom of the furnace body, the molten slag can be dropped from the slag port without cooling, and the incineration ash can be continuously and stably melted. it can.

[0012]

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of an incineration ash melting treatment apparatus according to the present invention. The electromagnetic induction heating furnace comprises a furnace body 1, a lid 2 for closing the upper portion of the furnace body 1, a slag opening 4 connected to the lower portion, and an induction coil 3 wound around the outer periphery of the furnace body, and a heating element 5 is laminated in the furnace. Deploy. The heating element 5 is formed by regularly or irregularly laminating a heat-resistant conductive material such as graphite or conductive ceramics formed in a columnar shape or a spherical shape. A gas introduction pipe 6 is connected to the lid 2 and is inserted into the furnace. The gas introduction pipe 6 is for supplying gas into the furnace,
The gas is preferably an inert gas such as nitrogen, helium, or argon, or a reducing gas containing no oxygen. Further, an incineration ash input port 30 and an upper exhaust port 31 are connected to the lid 2, and the incineration ash input port 30 is connected to a conveyor (not shown) or the like to convey the incineration ash to the inside of the furnace. The gas can be continuously administered, and the upper exhaust port 31 discharges a part of the gas introduced into the furnace and the gas generated by melting the incineration ash. The other part of the gas is discharged from a lower exhaust port 33 connected to a protective wall 32 installed around the lower outlet port 4 of the furnace body 1. In this case, the hot gas and the melt in the furnace can be simultaneously drawn out. The gas drawn from the inside of the furnace through the upper exhaust port 31 and the lower exhaust port 33 is collected from the exhaust system 40 or separately introduced into a downstream gas treatment facility (not shown) to render it harmless. In addition, the molten slag that falls from the outlet 4
It is taken out as water granulation slag in a cooling water tank (not shown) provided below it.

Further, as shown in FIG. 2, the inner surface of the furnace body 1 is constituted by uneven inner walls 20 and 21. This is for always interposing the incineration ash that is thrown in between the laminated heating element 5 and the inner wall.

Therefore, in the method for melting incinerated ash according to the present invention, the heating element 5 is heated by energizing the induction coil 3, the incinerated ash injected into the furnace is melted in an inert gas atmosphere, and the molten slag is melted. Then, the laminated portion of the heating element is dropped and the molten slag is discharged from the outlet 4 together with the high temperature gas in the furnace.
Then, the operation of continuously supplying the incinerated ash from the charging port 30, melting it, and extracting it from the slag port 4 is repeated. It is desirable to keep this operating temperature at or above the melting point of incinerated ash.
About 0 to 1600 ° C is suitable.

With the treatment method according to the present invention, an applied power of 35 k
Using the W electromagnetic induction heating furnace, the incineration ash shown in Table 1 was melted, and as a result, molten slag as shown in the same table was obtained.

[0017]

[Table 1]

From the specific volume, a volume reduction of 1/3 to 1/5 was confirmed, and in comparison with the presence or absence of the introduction of the inert gas at that time, the introduction of the inert gas was more stable on the inner surface of the furnace and no damage was observed. The heating element also survived several times. Moreover, when the obtained molten slag was subjected to a dissolution test by an infiltration method, the data obtained by changing the pH of the solution in consideration of acid rain and the like as shown in Table 2 are below the landfill standard and can be sufficiently harmless. It was confirmed to be a thing.

[0019]

[Table 2]

[0020]

According to the present invention, the gas atmosphere in the furnace can be adjusted and the contact between the inner wall of the furnace and the heating element can be suppressed, so that the consumption of the heating element can be suppressed and the life of the refractory material on the inner wall can be suppressed. Can be significantly extended. Further, since the high-temperature gas in the furnace can be extracted together with the molten slag from the outlet, the molten slag can be discharged without being excessively cooled. As a result, the incineration ash can be melted stably and continuously for a long time, and the incineration ash can be reduced in volume and harmless.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of an incineration ash melting treatment apparatus which is an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 ... Furnace body, 2 ... Lid, 3 ... Induction coil, 4 ... Slag outlet, 5 ...
Heating element, 6 ... Gas introduction pipe, 10 ... Incinerated ash, 11 ... Molten slag, 20, 21 ... Uneven inner wall, 30 ... Incinerated ash charging port, 3
1 ... Upper exhaust port, 32 ... Protective wall, 33 ... Lower exhaust port.

Front Page Continuation (72) Inventor Toshiaki Arato 7-1-1 Omika-cho, Hitachi City, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Kiyoyuki Nishikawa 800 Tomita, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Living Equipment Division, Hitachi, Ltd. (72) Etsuo Hashida, Inoue, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture 800, Tomita Living Equipment Division, Hitachi, Ltd. (72) Hiroshi Miyadera, 7-1, 1-1, Mikamachi, Hitachi City, Ibaraki Prefecture Hitachi, Ltd., Hitachi Research Laboratory

Claims (4)

[Claims] 1. A treatment method in which a conductive heating element is laminated inside a furnace, and the conductive heating element is induction-heated to melt the incineration ash injected into the furnace. A method for melting incinerated ash, which comprises introducing and heating the conductive heating element in the gas atmosphere. 2. The incineration ash according to claim 1, wherein the gas is either an inert gas such as nitrogen, helium, or argon, or a reducing gas containing no oxygen, and the gas is continuously introduced into the furnace. Melt processing method. 3. An inner wall of an electromagnetic induction heating furnace is composed of a refractory material formed in a vertical direction in a concavo-convex shape, and a heat-resistant conductive material such as graphite or conductive ceramics is provided in the furnace in a columnar shape or a spherical shape. The heating element formed in the above is laminated, a gas introducing pipe is installed in the furnace, the induction coil of the electromagnetic induction heating furnace is energized, the heating element is heated in the introduced gas atmosphere, and the electromagnetic induction heating is performed. An incinerator ash melting treatment apparatus, characterized in that incinerated ash injected from a charging port provided at the top of a furnace is melted and molten slag is taken out from a slag port provided at the bottom of the electromagnetic induction heating furnace. 4. The lower exhaust gas according to claim 3, wherein the gas introduced from the gas introduction pipe is provided on a protective wall that is connected to surround an upper exhaust port provided at an upper part of the electromagnetic induction heating furnace and the slag port. A method for incinerating ash melting, in which the introduction gas and the gas generated in the furnace are sucked to the outside of the furnace through the suction port and the lower exhaust port.