JP2855265B2 - Electric resistance melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric resistance melting furnace.

[0002]

2. Description of the Related Art In a conventional electric resistance melting furnace, as shown in FIG. 7, three electrodes 2a, 2b, 2c are arranged in a furnace body 1, and power supply equipment 3 is connected to these electrodes 2a, 2b, 2c. The molten metal 4 such as the refuse incineration ash in the furnace body 1 is heated and melted by Joule heat by applying a three-phase alternating current from the furnace, and the obtained molten metal is discharged from the tap hole 5 and melted. The slag 4a was configured to be discharged from the slag discharge port 6. Reference numeral 7 denotes an inlet for the material to be melted, and 8 denotes an exhaust port.

[0003]

However, in the conventional electric resistance type melting furnace having such a structure, the material to be melted 4 between the adjacent electrodes 2a, 2b, 2c easily generates heat when energized. Electric current is not applied to the material 4 to be melted between the furnace body 1 and 2a, 2b, 2c, and is gradually heated and melted by the heat from the molten metal generated on the electrode side.
There was a problem that the melting efficiency was very poor.

[0004] An object of the present invention is to provide an electric resistance type melting furnace capable of performing melting efficiently.
Another object of the present invention is to provide an electric resistance type melting furnace capable of efficiently preheating a material to be melted from its surroundings. Another object of the present invention is to provide an electric resistance melting furnace capable of suppressing consumption of the heating means.

[0005]

According to a first aspect of the present invention, there is provided an electric resistance melting furnace, wherein electrode plates are respectively arranged on opposing surfaces of a heat-resistant insulating container, and conductive melting is provided in the heat-resistant insulating container between the electrode plates. A tank is disposed, and the conductive melting tank is electrically divided with a heat-resistant insulating material interposed therebetween so that a portion on a side facing each electrode plate forms a pair of internal electrodes, and is electrically connected to each electrode plate. It is characterized in that each space between the conductive melting tank and the melting tank is filled with particles of a carbon material.

In an electric resistance melting furnace having such a structure,
When the material to be melted is placed in the conductive melting tank and a voltage is applied between the two electrode plates, a current flows from one electrode plate to the carbon material between the electrode plate and one internal electrode formed by the conductive melting tank. Through the particle layer, through the one internal electrode, through the material to be melted in the conductive melting tank, through the other internal electrode formed by the conductive melting tank, the other internal electrode and the other electrode plate And flows to the other electrode plate through the particle layer of the carbon material. When a current flows through the carbon material particle layer on each side, spark discharge occurs between adjacent carbon material particles, and Joule heat is generated within the carbon material particles due to the resistance of the carbon material particles. The carbon material particles are heated and heated by the spark discharge generated between the particles of the carbon material, and as a result, the electric resistance of the particles of the carbon material is reduced, the current flow is improved, and a large amount of Joule heat is generated. I do. Then, the heat of the spark discharge and the Joule heat are added to store a high temperature in the layer of the carbon material particles, and the layer of the carbon material particles becomes extremely high.

[0007] The conductive melting tank is surrounded by the particle layer of such a high-temperature carbon material, and the material to be melted in the conductive melting tank is uniformly heated.

Although the electric resistance of the material to be melted greatly varies depending on the temperature, in this electric resistance type melting furnace, the material to be melted in the conductive melting tank is evenly heated by the surrounding carbon material particle layer, so that the electric resistance is uniform. The electric current flows uniformly in each part, and the unmelted material is quickly heated as a whole by the uniform heating and uniform current from the high-temperature carbon material particle layer, and the molten material is in a molten fluid state. Therefore, the material to be melted can be efficiently melted.

According to a second aspect of the present invention, there is provided an electric resistance melting furnace, wherein upper portions of respective portions in the heat-resistant insulating container filled with particles of the carbon material are closed with lids.

When the upper portions of the respective portions of the heat-resistant insulating container filled with the particles of the carbon material are closed with the lids, it becomes difficult for air to enter and the consumption of the particles of the carbon material can be suppressed. .

[0011]

1 to 4 show an embodiment of an electric resistance melting furnace according to the present invention. The electric resistance type melting furnace of this example is a melting furnace for melting incineration ash, fly ash, and the like, and is provided in a space on a facing surface of a ceramic heat-resistant insulating container 9 having a bottom plate 9a and both side plates 9b and 9c. Positive and negative electrode plates 10a and 10b made of carbon are respectively attached. Positive and negative electrode plates 10a, 10b
Are connected to current-carrying conductors 11a and 11b.

At the center of the heat-resistant insulating container 9 between the positive and negative electrode plates 10a and 10b, a bottomed cylindrical conductive melting tank 12 is provided. The conductive melting tank 12 is electrically divided with a heat-resistant insulating material 12c interposed therebetween such that a portion facing the positive and negative electrode plates 10a and 10b forms a pair of internal electrodes 12a and 12b. I have. The internal electrodes 12a and 12b are formed of carbon,
2c is formed of ceramics. An overflow pipe 13 made of carbon is connected to a side surface of the conductive melting tank 12 to overflow the molten slag 4a.

In each space between the positive and negative electrode plates 10a and 10b and the conductive melting tank 12, particles 14 of carbon material are provided.
a and 14b are filled. As the carbon substance, processed charcoal such as charcoal, coal, activated carbon, and coke is used, and in this example, charcoal is used. Particles of carbon material 14
The sizes of a and 14b are about 5 to 20 mm. When the conductive melting tank 12 is small, particles of a carbon material of 5 mm or less can be used. Particles 14a, 1 of carbon material
If the size of 4b is too large, the gap between the particles of the adjacent carbon material becomes too large, the current flow between the particles of the carbon material becomes poor, and the Joule heat does not increase,
Not preferred.

The upper portions of the respective portions in the heat-resistant insulating container 9 filled with the carbon material particles 14a and 14b are closed with lids 15a and 15b made of a heat-resistant insulating material, respectively. Further, a lid 16 made of a heat-resistant insulating material is also placed on the upper part of the conductive melting tank 12. A molten material charging cylinder 17 is provided through the lid 16, and an exhaust cylinder 18 is provided through the lid 15b. On the upper side in the conductive melting tank 12, a partition wall 19 for separating the molten material 4 and the molten slag is provided.

Next, the operation of the electric resistance type melting furnace having such a structure will be described. The molten material 4 is charged into the conductive melting tank 12 from the molten material charging cylinder 17, and the positive and negative electrode plates 1 are charged.
When a positive / negative DC voltage is applied from a DC power supply (not shown) via the current-carrying conductors 11a and 11b to the electrodes 0a and 10b, current flows from the positive electrode plate 10a to the layer of carbon material particles 14a,
One internal electrode 12a, the melt 4 and the other internal electrode 1
2b, flows to the negative electrode plate 10b through the layer of the carbon material particles 14b. Particles 14a, 1 of carbon material on each side
When a current flows through the layer 4b, a spark discharge is generated between adjacent carbon material particles, and the carbon material particles 1
4a, 14b, particles 14a, 14
Joule heat is generated by the resistance b. The particles 14a and 14b of the carbon material are heated and heated by spark discharge generated between the particles 14a and 14b of the adjacent carbon material. Usually, particles 14a, 1 of adjacent carbon material
The contact between the contacts 4b has a very high electric resistance and hinders the flow of current. However, spark discharge does not not only hinder the flow of current but also generates a large amount of heat due to spark discharge.

As a result of the heat generated by the spark discharge, the electrical resistance of the carbon material particles 14a and 14b is reduced, the current flow is improved, and a large amount of Joule heat is generated. Then, the heat of the spark discharge and the Joule heat are added to store a high temperature in the layer of the particles 14a and 14b of the carbon material.
The layers a and 14b become very hot.

The particles 14 of such a high-temperature carbon material
The conductive melting tank 12 is surrounded by the layers a and 14b, and the material to be melted 4 in the conductive melting tank 12 is uniformly heated. Although the electrical resistance of the material to be melted 4 greatly differs depending on the temperature,
In this electric resistance type melting furnace, the material 4 to be melted in the conductive melting tank 12 is uniformly heated by the layers of the surrounding carbon material particles 14a and 14b, so that the electric resistance is uniform, and the current flows uniformly in each part. The unmelted material 4 is quickly brought into a molten state as a whole by the uniform heating and the current flowing uniformly from the layer of the high-temperature carbon material particles 14a and 14b. It can be performed efficiently. The obtained molten slag 4 a accumulates on the bottom side in the conductive melting tank 12.

When the upper portions of the respective portions in the heat-resistant insulating container 9 filled with the carbon material particles 14a and 14b are closed with lids 15a and 15b, respectively, it becomes difficult for air to enter, and the carbon material particles 14a and 14b Wear can be suppressed. When the carbon material particles 14a, 14b are consumed and reduced, the reduced carbon material particles 14 are reduced.
Refill a and 14b.

A carbon conductive melting tank 12 having an inner diameter of 130 mm
In the experiment using, particles 1 of carbon material consisting of charcoal
In the electric resistance melting furnace of the present invention using 4a and 14b, 10
The DC voltage is changed to the positive and negative electrode plates 10a, 1a by the constant current control of 0 A.
When the voltage was applied to 0b, the voltage between the electrode plates 10a and 10b was charged to 50 V, and 11.07 kg of the material to be melted 4 could be melted in one hour. 80mm inner diameter carbon conductive melting tank 1
2 using the electric resistance melting furnace of the present invention using carbon material particles 14a and 14b made of charcoal,
DC voltage is controlled by positive and negative electrode plates 10a, 1 by constant current control of 60A.
When the voltage was applied to 0b, the voltage between the electrode plates 10a and 10b was charged to 50 V, and 4.3 kg of the material to be melted 4 could be melted in one hour.

When the carbon conductive melting tank 12 is directly charged without using the carbon material particles 14a and 14b, a molten slag passage is formed in the material 4 to be melted.
When the current of A flows, the voltage does not increase and the conductive melting tank 1
No molten state of the material to be melted 4 was formed inside 2. That is, current starts to flow in the passage in the specific material 4 to be melted, and only that portion becomes hot and melts, and the current easily flows, and the current hardly flows to other portions. It appears that the electrical energy input did not increase.

A comparison of the melting ability of the object 4 to be melted between the conventional three-phase AC electric resistance melting furnace and the electric resistance melting furnace of the present invention shows that the conventional three-phase AC electric resistance melting furnace. The furnace had a melting capacity of 300 Kg / m ² Hr per furnace surface area, whereas the electric resistance melting furnace of the present invention had a melting capacity of 800 Kg / m ² Hr.
Melting ability.

FIGS. 5 and 6 show another example of the conductive melting tank 12 used in the present invention. The conductive melting tank 12 of the present example has a bottomed rectangular tube shape. The conductive melting tank 1
2 also has positive and negative electrode plates 10a and 10
b is a pair of internal electrodes 12a and 12b
Are electrically divided with a heat-resistant insulating material 12c interposed therebetween. The conductive melting tank 1 having such a structure.
2, the same effect as in the above-described example can be obtained.

In the electric resistance type melting furnace shown in FIGS. 1 and 2, the opposite end faces of the heat-resistant insulating container 9 are opened, and the positive and negative electrode plates 10a and 10b are respectively attached so as to close them. However, the periphery of the heat-resistant insulating container 9 is closed, and the positive and negative electrode plates 1
It is also possible to adopt a structure in which 0a and 10b are arranged. Although not the above example, a tapping pipe for tapping the molten metal 4a may be connected to the bottom side of the conductive melting tank 12. Further, in the above-described example, the DC energizing method has been described. However, the electric resistance type melting furnace of the present invention can also be implemented by a single-phase AC energizing method. The material to be melted in the electric resistance melting furnace is not limited to incineration ash or fly ash, but may be any conductive material.

[0024]

The electric resistance type melting furnace according to claim 1 is
Electrode plates are arranged on the opposing surfaces of the heat-resistant insulating container, and a conductive melting tank is arranged in the heat-resistant insulating container between the electrode plates. Since the internal electrodes were electrically divided to form a pair of internal electrodes with a heat-resistant insulating material interposed between them, each space between each electrode plate and the conductive melting tank was filled with particles of carbon material. When a voltage is applied between the two electrode plates, a current flows through the components between the electrode plates, and a spark discharge occurs between particles of the adjacent carbon material in the carbon material particle layer on each side due to the flow of the current, Joule heat is generated in the particles of the carbon material due to the resistance of the particles of the carbon material, but the particles of the carbon material are heated and heated by spark discharge generated between the particles of the adjacent carbon material. Stuff The electrical resistance is lowered particles, a large amount of Joule heat better the flow of current is generated. Then, the heat of the spark discharge and the Joule heat are added to store a high temperature in the layer of the particles of the carbon material, and the layer of the particles of the carbon material becomes extremely high and heats the conductive melting tank from the surroundings. be able to. Therefore, the material to be melted in the conductive melting tank can be uniformly heated. When the material to be melted in the conductive melting tank is evenly heated by the surrounding carbon material particle layer, the electric resistance of the material to be melted is also substantially equal, an electric current flows uniformly to each part, and the unmelted material is melted. The object is quickly brought into a molten state as a whole by the uniform heating and the uniform flowing current, so that the object to be melted can be efficiently melted.

In the electric resistance type melting furnace according to the second aspect,
Since the upper portions of the respective portions in the heat-resistant insulating container filled with the particles of the carbon material are closed by the lids, it becomes difficult for air to enter and the consumption of the particles of the carbon material can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of an embodiment of an electric resistance melting furnace according to the present invention.

FIG. 2 is a perspective view in which a lid is removed and a part of a side wall is cut off in the electric resistance melting furnace of the present example.

FIG. 3 is a plan view of a conductive melting tank used in this example.

FIG. 4 is a side view of a conductive melting tank used in this example.

FIG. 5 is a plan view showing another example of the conductive melting tank used in the present example.

FIG. 6 is a side view showing another example of the conductive melting tank used in the present example.

FIG. 7 is a longitudinal sectional view of a conventional electric resistance melting furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2a, 2b, 2c Electrode 3 Power supply equipment 4 Melted material 4a Melted slag 5 Tap hole 6 Slag discharge port 7 Melted material charging port 8 Exhaust port 9 Heat resistant insulating container 9a Bottom plate 9b, 9c Side plate 10a, 10b Positive / negative 11a, 11b Current-carrying conductor 12 Conductive melting tank 12a, 12b Internal electrode 12c Heat-resistant insulating material 13 Overflow tube 14a, 14b Particles of carbon material 15a, 15b Lid 16 Lid 17 Melting material charging cylinder 18 Exhaust cylinder 19 Partition wall

Claims (2)

(57) [Claims] 1. An electrode plate is disposed on each of opposing surfaces of a heat-resistant insulating container, and a conductive melting tank is disposed in the heat-resistant insulating container between the electrode plates, and the conductive melting tank is provided on each of the electrode plates. A portion on the opposite side is electrically divided with a heat-resistant insulating material interposed therebetween so as to form a pair of internal electrodes, and a carbon material is provided in each space between each of the electrode plates and the conductive melting tank. An electric resistance type melting furnace characterized by being filled with particles. 2. The electric resistance type melting furnace according to claim 1, wherein upper portions of respective portions in the heat-resistant insulating container filled with the particles of the carbon material are closed by lids.