JPH10339584A - Plasma oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat efficiency by arranging a plurality of magnets by allowing identical electrodes to oppose an oven wall for constituting an oven body at the outer periphery of an oven body. SOLUTION: An oven wall 2 of a cylindrical oven body 1 where upper and lower parts are blocked is formed by high-temperature resistance refractory and a screw conveyor 3 for supplying a heated object is connected to the upper portion of the oven body 1. Then, a flame plasma burner 4 for discharging a high-temperature gas being turned into plasma into the oven body 1 is mounted to the upper portion of the oven body 1 around the connection part of the screw conveyor 3, and an exhaust port 5 for evacuating a melted slug is provided at the lower portion of the side wall of the oven body 1. Further, a group consisting of a plurality of electromagnets 6 is arranged at upper and lower stages so that identical electrodes oppose the oven wall 2 for constituting the oven body 1 at the outer periphery of the oven body 1, and a coil 8 of the electromagnets 6 is connected mutually in series and are excited from a DC power supply. Also, a cooling passage is formed in a magnetic body 7 and coolant is supplied from a coolant entrance 10a and is evacuated from a coolant exit 10b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a melting furnace, an incinerator,
The present invention relates to a plasma furnace used as a metal furnace, a glass melting furnace, a chemical reaction furnace, or the like.

[0002]

2. Description of the Related Art As plasma furnaces for injecting high-temperature gas into plasma from a plasma burner into a furnace, a plasma furnace using a transition type plasma burner, a plasma furnace using a non-transitional type plasma burner, and a flame plasma burner are used. There is a plasma furnace.

In a plasma furnace using a transfer type plasma burner, a heating object entering a furnace body is used as an electrode opposite to an internal electrode of the plasma burner, and a high voltage is applied between these electrodes so that the plasma burner and the heating object are applied. Is generated between them to heat the object to be heated.

In a plasma furnace using a non-transfer type plasma burner, an electrode of one polarity and an electrode of the opposite polarity are provided inside the plasma burner, and a high voltage is applied between the electrodes to pass between the electrodes. The working gas is turned into plasma and ejected into the furnace body, and the object to be heated is heated by the plasma gas.

[0005] In a plasma furnace using a flame plasma burner, air for burning fuel is converted into plasma, and the fuel is burned using the plasma to generate flame plasma, which is ejected into the furnace, and heated by the flame plasma. It heats things.

[0006]

However, in such a conventional plasma furnace, there is a problem that the plasma gas cannot be converged in the furnace and the thermal efficiency cannot be increased.

An object of the present invention is to provide a plasma furnace that can increase thermal efficiency.

It is another object of the present invention to provide a plasma furnace capable of efficiently transmitting a magnetic flux for converging a plasma gas in a furnace inside the furnace.

[0009]

SUMMARY OF THE INVENTION The present invention is to improve a plasma furnace equipped with a plasma burner for injecting high temperature gas into plasma into a furnace body.

[0010] The plasma furnace according to the first aspect is characterized in that a plurality of magnets are arranged on the outer periphery of the furnace body such that the same pole faces a furnace wall constituting the furnace body. .

In this way, a vortex of the ion current is generated at each location in the furnace corresponding to each magnet by Lorentz force,
In the reactor core, a plasma vortex is formed as a synthetic flow of the ion flow vortex, and the plasma vortex can be converged in the reactor core by the plasma vortex and by a magnetic mirror or a drift effect due to a non-uniform magnetic field.

[0012] The plasma furnace according to the second aspect is the first aspect.
Wherein the group of magnets is arranged in a plurality of stages in the axial direction of the furnace body.

With this arrangement, the plasma flame can be more efficiently converged at the core by the group of magnets at each stage.

According to a third aspect of the present invention, in the plasma furnace, a magnetic expansion plate formed of magnetic metal and having a larger area than an end surface of the magnet is attached to an end of the magnet on the furnace wall side. .

In this case, since the area of action of the magnet becomes large, the vortex of the ion flow generated by the Lorentz force at each location in the furnace corresponding to each magnet increases, and the vortex of the large ion flow at the core portion increases. The vortex of the plasma formed as a combined flow of the gas can make the plasma flame converge more efficiently in the core portion.

[0016]

1 to 4 show an embodiment of a plasma furnace according to the present invention in which the present invention is applied to a furnace for melting incineration ash and fly ash.

The plasma furnace includes a furnace body 1 having a cylindrical shape and having upper and lower parts closed, and a furnace wall 2 of the furnace body 1 is formed of a high temperature resistant refractory. A screw conveyor 3 for supplying a heating target made of raw ash to the center of the furnace body 1 is connected to the upper part of the furnace body 1. In the upper part of the furnace body 1 around the connection point of the screw conveyor 3, a flame plasma burner 4 as one of three plasma burners for injecting high temperature gas into plasma into the furnace body 1 is provided.
Mounted at 20 ° intervals. At the lower part of the side wall of the furnace body 1, a discharge port 5 for discharging molten slag is provided.

The outer periphery of the furnace body 1 has the same polarity (N in this example).
(Electrodes) facing the furnace wall 2 constituting the furnace body 1 so that a group of a plurality of (four in this example) electromagnets 6
They are arranged in columns. Each electromagnet 6 is made of a magnetic material 7 such as iron.
Are wound around the outer periphery of the coil. In this example, each coil 8 is arranged such that the end of the magnetic body 7 facing the furnace wall 2 has an N pole as shown in FIG.
And are connected in series with each other to be excited by the DC power supply 9. A cooling passage 10 is formed in the magnetic body 7, and cooling water is supplied to the cooling passage 10 from a cooling water inlet 10 a and a cooling water outlet 1
0b.

In such a plasma furnace, when a flame which has been turned into plasma from the flame plasma burner 4 is ejected into the inside of the furnace body 1, its ions are converted into each electromagnet 6 as shown in FIG.
When the plasma flame passes from the front to the back of the drawing when the furnace wall 2 side is an N pole due to the magnetic field caused by the magnetic field, the vortex A of the ion counterclockwise due to Lorentz force near the N pole of each electromagnet 6 Can be. Inside the plasma, ions are the main components of the momentum, and therefore appear phenomenally as a vortex of the plasma. In the core, the vortex A of these four ion flows
A vortex B of plasma is generated clockwise as a combined flow of The plasma vortex B allows the plasma flame to converge at the core.

When the groups of electromagnets 6 are arranged in a plurality of stages in the axial direction of the furnace body 1 as shown in the drawing, the plasma flame can be more efficiently converged in the core by the groups of electromagnets 6 in each stage.

As shown in FIG. 6, when the end of the magnetic body 7 facing the furnace wall 2 is set to the S pole by the electromagnet 6, it is assumed that the plasma flame passes from the front to the back of the drawing. In the vicinity where the S pole of each electromagnet 6 exists, an ion vortex A is formed clockwise due to Lorentz force. In the reactor core, a plasma vortex B is formed counterclockwise as a combined flow of the four ion flow vortices A. The plasma vortex B allows the plasma flame to converge at the core.

Although the eddy current described above is observed, plasma ions are converged due to other unobservable effects such as a magnetic mirror due to a non-uniform magnetic field generated by the electromagnet 6, a drift effect, and the like. Plasma burner 4
In the case of a melting furnace, even a raw material that does not melt when the electromagnet 6 is not attached can be melted by attaching the electromagnet 6 and converging the plasma flame. On the other hand, when the plasma flame is converged by the electromagnet 6, the high-temperature plasma flame does not contact the furnace wall 2, and the life of the furnace wall 2 can be extended as compared with the case where the electromagnet 6 is not provided.

The above description has been made in connection with the case where the source of the plasma flow is the flame plasma burner 4, but this effect is obtained when the source of the plasma flow is ejected from the non-transfer type plasma burner. Can be obtained similarly.

FIG. 7 shows another embodiment of the plasma furnace according to the present invention. In this embodiment, a magnetic metal is formed on the end of the magnetic body 7 of the electromagnet 6 on the furnace wall 2 side. A magnetic expansion plate 7a having a larger area than the end face of the magnetic body 7 is attached. The electromagnet 6 has a cooling box 10c for containing cooling water for cooling the magnetic expansion plate 7a.
Is provided. One of the cooling passages 10 formed in the magnetic body 7 is open in the cooling box 10c,
The other opening of the cooling passage 10 is a cooling water inlet 10a. A drain box 10d is connected to the cooling box 10c, and an opening of the drain pipe 10d serves as a cooling water outlet 10b.

In such a plasma furnace, the magnetic expansion plate 7
Since the magnetic action area is increased by a, the vortex A of the ion flow generated by the Lorentz force at each location in the furnace body 1 corresponding to each electromagnet 6 increases, and the vortex A of these large ion flows at the core portion increases. The plasma vortex B formed as a synthetic flow can make the plasma flame converge more efficiently in the core (FIG. 8).

FIG. 9 shows an example of a specific structure of the flame plasma burner 4 used in the plasma furnace shown in FIGS. 1 and 2 described above.

The flame plasma burner 4 is provided in the mixing chamber 1
1 is provided. This mixing cylinder 12
A tubular portion 12b having a flange portion 12a at a base end, an enlarged-diameter stepped portion 12c continuously provided at a distal end of the cylindrical portion 12b, and an outlet from an inlet side connected to an outer periphery of the enlarged-diameter stepped portion 12c; Tapered tube part 1 whose inner diameter gradually decreases toward the side
2d and a flange portion 12e provided on the outer periphery of the distal end of the tapered tubular portion 12d.

At the inlet side of the mixing chamber 11, an air supply unit 15 having a double structure comprising an outer cylinder 13 and an inner cylinder 14 is provided to the mixing cylinder 12.
Is provided. Pressurized air is supplied to the air supply unit 15 from the outside. Outer cylinder 1
Reference numeral 3 has flange portions 13a and 13b at both ends, and the flange portion 13b is overlapped and connected to the flange portion 12a of the mixing cylinder 12.

In the inner cylinder 14, there is provided a plasma generating means 16 for converting an air flow flowing through the inner cylinder 14 into a plasma to generate a plasma flow. The plasma generating means 16 includes an annular insulating support 17 along the inner circumference of the inner cylinder 14.
A plurality of rod-shaped electrodes 18 are supported through the insulating support 17, and these electrodes 18 are used as anodes.
By using the inner cylinder 14 as a cathode and applying a high voltage between these electrodes, the airflow flowing through the inner cylinder 14 is turned into plasma.

Between the outer cylinder 13 and the inner cylinder 14, swirling blades 19 are spirally arranged, and these outer cylinder 13 and the inner cylinder 14 are arranged.
The air flow flowing between them is swirled to enclose and converge the plasma flow. The inner cylinder 14 is supported by the outer cylinder 13 by the turning blade 19.

A plurality of fuel injection nozzles 20 for ejecting fuel around the plasma flow in the mixing chamber 11 and mixing the fuel into a swirling flow are provided through the enlarged diameter step 12 c of the mixing cylinder 12. At the outlet side of the mixing chamber 11, a combustion cylinder 21 is connected to a flange 12e of the mixing cylinder 12 via a flange 21a, and a cylindrical combustion chamber 22 is formed inside.
The other end of the combustion cylinder 21 is provided with a flange portion 21b. A plurality of ignition plugs 23 are connected to such a combustion cylinder 21 so as to pass therethrough. Four electromagnets 24 are arranged at 90 ° intervals on the outer periphery of the combustion cylinder 21 so that the same pole (N pole in this example) exists around the combustion chamber 22. These electromagnets 24 are magnetic bodies 25 made of iron core.
The coils 26 are wound in the same direction, and the respective coils 26 are connected in series so that an exciting current is supplied from a DC power supply (not shown).

A cooling passage 27 through which cooling water flows is formed in the magnetic body 25 of each electromagnet 24. A cooling jacket 28 is provided on the outer periphery of the combustion cylinder 21 in a concentric arrangement. Both ends of the cooling jacket 28 are connected to the flange portions 21 a and 21 b of the combustion tube 21, and a cooling chamber 29 is formed between the combustion tube 21 and the cooling jacket outer wall 28. Cooling water is supplied to the cooling chamber 29 from the opening 27 a of the cooling passage 27 of the magnetic body 25. The cooling water in the cooling chamber 29 is cooled by the cooling jacket outer wall 28.
Is drained from the drain port 28a of the air conditioner. At the location of the spark plug 23, an isolation cylinder 30 is provided so as to isolate it from the cooling water.

The tip of such a flame plasma burner 4 is attached to the upper part of the furnace body 1 at a burner port 31 provided on the upper part of the furnace body 1.

The flame plasma burner 4 having such a structure
According to this, since the electromagnet 24 is arranged on the outer periphery of the combustion cylinder 21 so that the same polarity exists, the plasma flame can be converged for the same reason as described above. By setting such a flame plasma burner 4 and the furnace body 1 of the present invention as a set, the convergence of the plasma flame can be made more remarkable.

FIG. 10 shows an example of a specific structure of the non-transition type plasma burner described above.

The non-transition type plasma burner 4 'is made of a metal and cylindrical burner bodies 32a, 32b.
3 are electrically insulated and connected. From the upper part of the upper burner body 32a, a tungsten negative electrode 35 is formed via an insulating sleeve 34.
Is inserted inside. The negative electrode 35 is connected to a cathode of a DC power supply (not shown) by a cathode high-voltage cable 36. The lower burner body 32b is connected to an anode of a DC power supply by an anode high-voltage cable 37, and the burner body 32b functions as an anode serving as a counter electrode to the negative electrode 35. Upper burner body 32a
Is connected to a working gas introduction pipe 38, from which working gas is supplied to a vortex chamber 39 in the burner body 32a. The cooling passage 40 is provided in the burner bodies 32a and 32b.
a, 40b are provided, and each burner body 32a, 3b is provided by cooling water supplied from cooling water supply ports 41a, 41b.
2b is cooled.

Such a non-transfer type plasma burner 4 '
Then, the working gas supplied from the working gas introduction pipe 38 becomes a swirling flow in the vortex chamber 39 and the negative electrode 35
Plasma is generated by a high voltage between the anode and the anode composed of the burner body 32b, and a plasma flow is blown into the furnace body 1 from the burner port 31 on the furnace body 1 through the throat 42.

In the above example, the case where the present invention is applied to a melting furnace has been described. However, the present invention is not limited to this, and plasma furnaces such as incinerators, metal furnaces, glass melting furnaces, chemical reaction furnaces, and the like. The same can be applied to.

[0039]

According to the plasma furnace of the present invention, a plurality of magnets are arranged on the outer periphery of the furnace body so that the same pole faces the furnace wall constituting the furnace body. Vortex of the ion flow due to Lorentz force is generated at each part of the plasma, and plasma vortex is generated as a composite flow of the vortex of the ion flow at the core, and the magnetic vortex due to the non-uniform magnetic field, drift effect, etc. This allows the plasma flame to converge at the core. Therefore, the plasma flame heat can be further increased, and the object to be heated can be heated at a higher temperature than in a conventional plasma furnace.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a plasma furnace according to the present invention in which the present invention is applied to a melting furnace.

FIG. 2 is a plan view of the plasma furnace shown in FIG.

FIG. 3 is a longitudinal sectional view of an electromagnet provided in the plasma furnace shown in FIG.

FIG. 4 is an explanatory diagram showing a connection state of coils of each electromagnet provided in the plasma furnace of the present example.

FIG. 5 is an explanatory diagram showing a flow of a plasma vortex in the furnace when the N pole of each electromagnet is opposed to the furnace.

FIG. 6 is an explanatory diagram showing a flow of a vortex of plasma in a furnace when an S pole of each electromagnet is opposed to the furnace;

FIG. 7 is a partially cut-away enlarged perspective view showing another example of the embodiment of the plasma furnace according to the present invention.

FIG. 8 is an explanatory diagram showing a flow of a vortex of plasma in the furnace when the N pole of each electromagnet is opposed to the furnace in the plasma furnace of FIG. 7;

FIG. 9 is a longitudinal sectional view showing an example of a specific structure of a flame plasma burner used in the plasma furnace of the present invention.

FIG. 10 is a longitudinal sectional view showing an example of a specific structure of a non-transfer type plasma burner used in the plasma furnace of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2 Furnace wall 3 Screw conveyor 4 Flame plasma burner 4 'Non-transition type plasma burner 5 Discharge port 6 Electromagnet 7 Magnetic body 7a Magnetic expansion plate 8 Coil 9 DC power supply 10 Cooling passage 10a Cooling water inlet 10b Cooling water outlet 10c Cooling box 10d Drain pipe 11 Mixing chamber 12 Mixing cylinder 13 Outer cylinder 14 Inner cylinder 15 Air supply unit 16 Plasma generating means 17 Insulating support 18 Electrode 19 Swirling vane 20 Fuel injection nozzle 21 Combustion cylinder 22 Combustion chamber 23 Spark plug 24 Electromagnet 25 Magnetic body 26 Coil 27 Cooling passage 28 Cooling jacket 29 Cooling chamber 30 Isolation tube 31 Burner port 32a, 32b Burner body 33 Insulating plate 34 Insulating sleeve 35 Negative electrode 36 Cathode high-voltage cable 37 Anode high-voltage cable 38 Working gas inlet tube 39 Vortex chamber 40a, 40b Cooling passage 41a, 41b Cooling water supply port 42 Throat A Vortex of ion flow B Vortex of plasma

Claims (3)

[Claims] 1. A plasma furnace equipped with a plasma burner for injecting high temperature gas into plasma into a furnace body, wherein a plurality of electrodes are provided on the outer periphery of the furnace body such that the same pole faces a furnace wall constituting the furnace body. A plasma furnace, wherein a magnet is disposed. 2. The plasma furnace according to claim 1, wherein the group of magnets is arranged in a plurality of stages in an axial direction of the furnace body. 3. The magnetic expansion plate according to claim 1, wherein a magnetic expansion plate made of magnetic metal and having a larger area than an end surface of the magnet is attached to an end of the magnet on the furnace wall side. Plasma furnace.