JPH1182983A - Fly ash treating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fly ash treating system in which treatment of fly ash is simplified by utilizing the retaining heat of a molten metal effectively and short circuit of electrode through a fused salt is prevented when an electric resistor type incineration ash melting furnace is employed. SOLUTION: A heat retaining tank 11 coupled with an incineration ash melting furnace 20 comprises a section 12 for receiving molten metal being discharged from the incineration ash melting furnace 20 into the heat retaining tank 11, and a section 15 for discharging the molten metal to the outside of the heat retaining tank 11. The heat retaining tank 11 is coupled with a pipe 13 for introducing fly ash externally and provided with a heater 16 for heating the molten metal in the heat retaining tank 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating fly ash generated when incinerating industrial waste.

[0002]

2. Description of the Related Art Incinerated ash discharged from incineration of industrial waste in an incinerator contains main ash and fly ash (dust contained in exhaust gas generated in the incinerator). This incineration ash is then melted in an incineration ash melting furnace, and the main ash becomes molten slag and molten metal. On the other hand, fly ash is a molten salt mainly composed of salts such as NaCl and CaCl ₂ . The melts of these main ash and fly ash are in the order of specific gravity, molten metal, molten slag,
Since it is a molten salt, layers are formed from the bottom in this order in the furnace tank.

For melting the above incinerated ash, for example, an electric resistance melting furnace is used. 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 so that Joule heat is generated in the molten slag. Has become.

[0004]

However, if fly ash is also introduced into the above-mentioned melting furnace together with the main ash, the fly ash generates a large amount of molten salt, so that the molten salt is located above the molten slag in the furnace tank. As a result, the electrode is immersed in the molten slag and at the same time penetrates the molten salt. Molten salt has much higher conductivity than molten slag. Therefore, when the incineration ash melting furnace is of the electric resistance type, electricity is short-circuited and flows through the molten salt layer between the plurality of electrodes instead of the molten slag (molten salt). Power concentration to). 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.

Further, when mixing the main ash and the fly ash in the incineration ash melting furnace, a premixing hopper for mixing the main ash and the fly ash is added before the furnace ash is introduced into the furnace tub, or the furnace is operated. In such a case, it is necessary to add a stabilizer, which not only complicates the apparatus but also complicates the operation thereof.

On the other hand, the molten metal is extracted from the bottom of the furnace tank of the incineration ash melting furnace, solidified by natural cooling or forced cooling, and reused as metal resources. However, the thermal energy of the molten metal is released during cooling without being used at all, which is not preferable in terms of energy utilization.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional apparatus, in which the operation of the melting furnace is simple, the energy of the molten metal can be effectively used, and when the melting furnace is an electric resistance type, incineration ash is used. It is an object of the present invention to provide a fly ash treatment apparatus which can avoid a short circuit between electrodes in an electric resistance type melting furnace at the time of melting.

[0008]

According to the present invention, a heat holding tank connected to an incineration ash melting furnace is provided for the above purpose. The heat holding tank has a receiving part for receiving the molten metal discharged from the incineration ash melting furnace into the heat holding tank, and a discharge part for discharging the molten metal out of the heat holding tank. Furthermore, a fly ash introduction pipe for introducing fly ash from the outside into the heat holding tank is connected to the heat holding tank, and a heating device for heating the molten metal in the heat holding tank is provided. .

In the present invention, the fly ash introduction pipe is provided such that the tip is located below the upper surface of the molten metal in the heat holding tank, and fly ash is introduced into the molten metal in the fly ash introduction pipe. It is desirable to be connected to the pumping device so as to be forcibly fed.

In the apparatus of the present invention having the above-described configuration,
Of the incinerated ash, only the main ash is charged into the incineration ash melting furnace, and the fly ash is charged into the heat holding tank of the present invention.

The main ash is melted in an incineration ash melting furnace to form a molten slag layer on the molten metal layer in the furnace tank. Since no fly ash is contained, no molten salt layer is formed on the molten slag layer. Therefore, even if the melting furnace is an electric resistance melting furnace, the above-described short circuit between the electrodes does not occur.

[0012] The molten metal layer formed at the bottom of the furnace tank of the incineration ash melting furnace is discharged from the discharge port and brought to the heat holding tank. When the molten metal enters the heat holding tank, it cools slightly, but is heated by a heating device to maintain a temperature sufficient for melting fly ash. The fly ash introduced from the fly ash introduction pipe comes into contact with the molten metal and melts, and a molten salt layer is formed on the molten metal layer. The molten metal and molten salt are discharged according to the timing and method as appropriate. Since there is no electrode in this heat holding tank, there is no problem such as a short circuit of the electrode, and the heat of the molten metal is sufficiently utilized for melting fly ash.

The contact between the fly ash and the molten metal is extremely effective when the fly ash is forcibly fed into the molten metal by a pumping device.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The fly ash treatment apparatus 10 according to the present embodiment shown in FIG. 1 is connected to an incineration ash melting furnace 20.

As an example of the melting furnace 20 for melting incineration ash, an electric resistance melting furnace is shown, and a plurality of electrodes 22 are inserted into a furnace tank 21 from above. A discharge pipe 23 serving as a molten metal discharge port is provided at the bottom of the furnace tank 21.

On the other hand, the fly ash treatment device 10 has a heat holding tank 11. The heat holding tank 11 is similar to the melting furnace 20 described above.
It is made of a heat-resistant material, and a receiving portion 12 for receiving the molten metal discharged from the melting furnace 20 is provided in the upper portion in the form of an opening. The receiving part 12 has a discharge pipe 2 serving as a molten metal discharge port of the melting furnace 20 described above.
Exit 3 is facing. Further, a fly ash introduction pipe 13 for introducing fly ash from outside is connected to an upper portion of the heat holding tank 11. As shown in the figure, the fly ash introduction pipe 13 has a lower end located below the upper surface of the molten metal M in the tank, and the fly ash is forcibly forced into the molten metal M by a pumping device (not shown). It is good that they are sent in a special way.

Further, an exhaust pipe 14 for discharging gas generated by processing in the tank is connected to an upper portion of the heat holding tank 11, and a molten metal extracting pipe 15 is provided at a lower portion. .

An induction coil 16 is wound around the outer periphery of the heat holding tank 11 as a heating device. This heating device is not limited to the induction coil, and it goes without saying that other heating means may be used as long as the temperature of the molten metal M in the tank can be raised.

In this embodiment, the fly ash is melted in the following manner.

The main ash among the incinerated ash is incinerated ash melting furnace 20
And melted by Joule heat between the electrodes 22,
The lower layer is molten metal, and the upper layer is molten slag. At that time, fly ash is not injected into the melting furnace 20,
There is no molten salt layer on the molten slag layer. Therefore, a short circuit between the electrodes 22 due to the molten salt layer does not occur as conventionally occurred.

The molten metal is discharged from the discharge pipe 23 of the melting furnace 20 and flows into the heat holding tank 11 from the receiving portion 12 of the heat holding tank 11. Fly ash is introduced into the heat holding tank 11 through a fly ash introduction pipe 13. At this time, when the lower end of the fly ash introduction pipe 13 enters into the molten metal layer M, the fly ash is forcibly forced by the gas as appropriate.
It is pumped inside. The molten metal layer M is heated to a temperature sufficient to melt fly ash by the induction coil 16 as a heating device.

Thus, the fly ash is mixed with the molten metal layer M
To form a molten salt layer on the molten metal layer M. The molten metal is a molten metal extraction tube 15
And the gas generated in the tank is exhausted from the exhaust pipe 14.

The present invention is not limited to the illustrated embodiment. First, the heat holding tank need not be separate from the melting furnace. What is essential is that the connection be made so that molten metal from the melting furnace can be received. Therefore, the connection
As shown in the figure, the discharge pipe of the molten metal provided in the melting furnace may face the receiving part of the heat holding tank, or the discharge pipe may be directly connected to the receiving part. At this time, it is preferable to connect the molten metal so that the temperature of the molten metal does not drop so much at the time of receiving.

The incineration ash melting furnace is not limited to the electric resistance type. If it is of the electric resistance type, the advantage that the short circuit of the electrode due to the molten salt is avoided is obtained,
Even with other types of melting furnaces, it is not necessary to add a stabilizing agent for melting fly ash or premixing before the addition, and it is possible to use the thermal energy of the molten metal.

[0026]

According to the present invention, as described above, the molten metal is transferred to the heat holding tank connected to the incineration ash melting furnace, where the fly ash is melted, so that the heat held by the molten metal is wasted. It can be used very effectively without the need for premixing the fly ash with the main ash, and without the need to add a stabilizer. There is an effect that the short-circuit of the electrode due to the molten salt is not accompanied.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fly ash processing apparatus 11 Heat holding tank 12 Receiving part 13 Fly ash introduction pipe 15 Extraction part (molten metal extraction pipe) 20 Incineration ash melting furnace

Claims (2)

[Claims] 1. A heat holding tank connected to an incineration ash melting furnace, the heat holding tank receiving a molten metal discharged from the incineration ash melting furnace into the heat holding tank, and the heat holding tank. With an outlet for discharging the molten metal out of the tank,
The heat holding tank is connected to a fly ash introduction pipe for introducing fly ash from the outside into the heat holding tank, and is provided with a heating device for heating the molten metal in the heat holding tank. Characterized fly ash processing equipment. 2. The fly ash introduction pipe is provided such that the tip is located below the upper surface of the molten metal in the heat holding tank,
2. The fly ash processing device according to claim 1, wherein the fly ash is connected to a pressure feeding device so that the fly ash is forcibly fed into the molten metal in the fly ash introduction pipe.