JPH11141851A - Method and device of discharging base metal of ash melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge base metal safely without shutting down the operation of a furnace. SOLUTION: In discharging the base metal M in a furnace main body 1, the molten metal M, which enters the inside of an extraction nozzle tube 22 from a metal extraction hole 21 that is formed at the bottom part of the furnace main body 1, is cooled down and solidified by a metal cooling and heating device 24. This solidified metal piece SM is continuously drawn from the inside of the extraction nozzle tube 22 by a pinch roller device 25, and then the molten metal M is discharged as the solidified metal piece SM.

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 for reducing the volume and harmlessness of incinerated ash from municipal solid waste and industrial waste by utilizing arc, plasma and Joule heat. The present invention relates to a method and an apparatus for discharging a metal in an ash melting furnace for discharging a molten base metal contained in a furnace bottom as a conductor.

[0002]

2. Description of the Related Art When melting incineration ash discharged from an incinerator in a plasma type, arc type or Joule heating type ash melting furnace, a metal molten layer (referred to as a base metal) is provided at the bottom of the furnace.
The incinerated ash is heated and melted on the base metal to form a molten slag layer, which is taken out from the slag port in an overflow manner. At that time, the metals contained in the incineration ash dissolve into the base metal, and the level of the molten metal of the base metal rises as the throughput increases. When the base metal rises, the molten slag layer becomes thinner, and fluctuations in the surface of the molten slag due to disturbances cause a large change in electrical resistance, making it difficult to operate the arc or plasma stably.

Conventionally, when the level of the base metal becomes high, the operation of the furnace is periodically stopped to incline the furnace, the molten slag is discharged from the slag discharge port, and then the lower base metal is discharged. A metal discharging operation was performed, and the molten slag layer was held so that the layer height became about 70 mm or more.

[0004]

However, the above-mentioned metal discharging operation is performed in the following manner. It is necessary to stop the operation of the ash melting furnace,
It takes time to restart, and the operating efficiency is reduced.
In addition, the molten slag layer becomes thinner, it is difficult to restart, and it takes time to reach stable steady operation. . Since the metal in the molten state is discharged, the extraction operation involves danger and requires skill. . Since the molten metal and the molten slag are mixed and discharged, there is a problem that recycling requires a separation operation in a later step.

According to the first aspect of the present invention, there is provided a method and an apparatus for discharging a base metal of an ash melting furnace capable of discharging only the base metal without stopping the operation by solving the above problems. The purpose is to do.

[0006]

According to a first aspect of the present invention, there is provided a method for discharging a base metal of an ash melting furnace according to the present invention. When discharging the molten base metal, the molten metal that enters the extraction nozzle cylinder from the metal extraction port formed facing the base metal at the bottom of the furnace body is cooled and solidified, and this solidified metal piece is extracted from the extraction nozzle cylinder. It is continuously extracted from the inside and the molten metal is discharged as solidified metal pieces.

According to a second aspect of the present invention, there is provided an apparatus for discharging a base metal of an ash melting furnace, comprising: a metal outlet opening at a bottom portion of a furnace main body for accommodating a molten base metal; and an extraction nozzle tube communicating with the metal outlet. Metal cooling means arranged in the extraction nozzle cylinder to cool and solidify the molten metal inside;
A pinch roller device capable of holding the solidified metal piece from the extraction nozzle cylinder below the extraction nozzle cylinder and continuously extracting the solidified metal piece.

According to each of the above structures, the molten base metal is solidified, continuously drawn out in a billet form, and the base metal is discharged, so that the discharging operation can be performed without stopping the operation of the furnace. Operation efficiency does not decrease. Further, since the molten metal is not directly handled, the metal extracting operation can be performed safely. Further, since slag is not mixed and discharged, the layer thickness of the molten slag does not decrease, stable operation can be continued, and work for separating metal and slag is not required.

Further, the invention of claim 3 is characterized in that the extraction nozzle cylinder having the above structure is provided with solidification metal melting means for heating and melting the outer periphery of the internal solidification metal piece. According to the above configuration, even when the extraction nozzle cylinder and the solidified metal piece may be fixed, the outer peripheral portion of the solidified metal piece is melted by the solidified metal melting means, so that the pinch roller device can smoothly extract the solidified metal piece. it can.

Further, according to the present invention, in the above structure, a metal tube coil spirally wound around an outer peripheral portion of the extraction nozzle tube, and a high-frequency power supply for supplying a high-frequency current to the metal tube coil And constitute the solidification metal melting means,
A metal cooling means is constituted by the metal tube coil and a cooling water supply device for supplying cooling water into the metal tube coil.

According to the above construction, the metal tube coil provides
Heating and cooling can be shared, and the configuration can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an embodiment of a plasma type ash melting furnace equipped with a metal discharge device according to the present invention will be described with reference to FIGS.

In FIG. 2, reference numeral 1 denotes a furnace body in which a melting chamber 2 for accommodating a molten base metal (molten metal) M is formed at the bottom, and an ash hopper 4 and an ash hopper 4 are formed on the front side wall. A pusher 5 is provided, and a discharge port 6 for discharging the molten slag MS is formed on the rear side wall. Further, a pair of torch insertion holes 7 formed in the top wall of the furnace body 1.
A and 7B have a cathode torch 8A as a plasma torch.
And a positive electrode torch 8B are respectively suspended via a torch elevating device (not shown).
The DC power supply 9 is connected to 8B. A working gas (for example, nitrogen gas) is supplied into the melting chamber 2 from a gas supply port of a furnace wall (not shown) and gas supply holes of the electrode torches 8A and 8B to form a plasma arc with the base metal M. It is composed of Reference numeral 10 denotes an exhaust gas outlet formed on the left side wall.

A slag discharge weir 11 in which a slag discharge groove is formed is provided at the slag discharge port 6.
A preheating burner 12 for preventing slag from solidifying in opposition to 1
Is arranged. A slag cooling device 13 including a cooling water tank 13a for cooling the molten slag MS with water and forming a granulated slag WS and a slag discharge conveyor 13b is arranged below the discharge port 6.

At the bottom of the furnace body 1, a base metal discharge device 21 according to the present invention is provided. As shown in FIG. 1, the base metal discharging device 21
Metal outlet 2 opened at the bottom of the furnace body 1 for housing
2, an extraction nozzle tube 23 which is suspended from the bottom of the furnace body 1 and communicates with the metal extraction outlet 22, a metal cooling means arranged in the extraction nozzle tube 23 for cooling and solidifying the molten metal inside, and Solidified metal piece S inside extraction nozzle cylinder 23
A metal cooling / heating device 24 also serving as a solidified metal melting means for heating and melting the outer periphery of M; and a billet-shaped solidified metal piece SM holding the solidified metal piece SM from the extraction nozzle cylinder 23
And a metal piece cutting device 26 (FIG. 2) that cuts the solidified metal piece SM at a predetermined length.

The metal cooling and heating device 24 includes a copper pipe pipe coil 31 which is an example of a metal pipe coil mounted and wound on a spiral groove 23a formed on the outer peripheral portion of the extraction nozzle cylinder 23, and a copper pipe pipe 31. A high-frequency power supply 32 for supplying high-frequency current to the coil 31 to heat the molten metal M in the extraction nozzle cylinder 23; and a cooling water supply device 33 for supplying cooling water to the copper pipe coil 31. Metal outlet 2
The molten metal M flowing into the extraction nozzle tube 23 from the second tube 2 can be cooled and solidified by the cooling water flowing in the copper pipe coil 31. When the solidified metal piece SM is firmly fixed to the inner surface of the extraction nozzle cylinder 23 and cannot be pulled out, a high-frequency current is supplied from the high-frequency power supply 32 to the copper pipe coil 31 to cause the outer peripheral surface of the solidified metal piece SM to be removed. Is heated and melted, the solidified metal piece SM can be smoothly extracted from the extraction nozzle cylinder 23 by the pinch roller device 25.

The pinch roller device 25 includes a pair of pull-out rollers 25a, 2 which are arranged in parallel with each other and sandwich the solidified metal piece SM or the dummy bar 34 at the time of starting with a predetermined rolling force.
5b and its driving device (electric motor or hydraulic motor). The metal piece cutting device 26 cuts the solidified metal piece SM to be pulled out to a predetermined length, and a driving cutter or a fusing device is used.

In the above configuration, a voltage is applied to both electrode torches 8A and 8B from the DC power supply 9 so that the electrode torch 8
A plasma arc is generated between A and 8B and the base metal M, and ash A of the ash hopper 4 is injected into the melting chamber 2 by the ash pusher 5 by a predetermined amount, and is heated and melted. Then, when the molten slag MS layer is formed on the base metal M and exceeds the level of the drain groove 11 a of the slag discharge weir 11, it overflows and is dropped and discharged from the discharge port 6 to the cooling water tank 13 a of the slag cooling device 13. Granulated slag WS is generated.

At this time, a dummy bar 34 is mounted from the outlet side of the extraction nozzle cylinder 23 to between the extraction rollers 25a and 25b to prevent the molten metal M from leaking, and the solidified metal piece SM cooled by the metal cooling and heating device 24 is removed. The lower end is connected to the upper end of the dummy bar 34.

Then, a predetermined amount of the ash A is melted, and the metal contained in the ash dissolves into the base metal M, and the layer thickness of the molten slag MS becomes unstable to form a plasma arc.
When the distance is about 0 mm, the pinch roller device 25 is activated, the dummy bar 34 is pulled downward, and then the solidified metal piece SM is pulled out in a billet shape. At this time, the molten metal M that has flowed into the extraction nozzle cylinder 23 from the metal extraction port 21 is cooled and solidified by the metal cooling / heating device 24, and is continuously extracted as solidified metal pieces SM.
When the solidified metal piece SM of a predetermined distance is pulled out, the solidified metal piece SM is cut by the metal piece cutting device 26, the dummy bar 34 is separated from the solidified metal piece SM, and further the solidified metal piece SM is cut at a predetermined length. You.

If the solidified metal piece SM is firmly fixed to the inner surface of the extraction nozzle cylinder 23 and is not pulled out when the pinch roller device 25 is started, a high-frequency current is supplied from the high-frequency power supply 32 to the copper pipe coil 31. Then, the solidified metal piece SM is heated and the outer peripheral surface is melted, so that the solidified metal piece SM can be smoothly pulled out from the extraction nozzle cylinder 23.

When the predetermined amount of the base metal M decreases, the pinch roller device 25 is stopped, and the extraction nozzle cylinder 23 is closed by the solidified metal piece SM. Next, when the base metal M increases, it is discharged in the same manner.

According to the above embodiment, even during operation, the pinch roller device 25 is driven by the base metal discharging device 21 to continuously convert the molten metal M into a solidified metal piece SM solidified in a billet shape. Can be extracted.
Therefore, it is not necessary to stop the operation of the ash melting furnace, and the steady operation can be continuously performed, so that the operation efficiency does not decrease. Further, since the molten slag MS is not discharged, the operation can be stabilized, and the work of separating the molten slag MS and the base metal M is not required. Further, the base metal M is discharged not as a molten state but as a solidified metal piece SM, so that the handling becomes easy and the base metal M can be discharged safely.

In the above-described embodiment, the metal outlet 21 is formed at the bottom of the furnace main body 1. However, a metal outlet may be formed at the side wall facing the bottom, and the solidified metal piece may be drawn to the side.

[0025]

As described above, according to the first and second aspects of the present invention, the molten base metal is solidified, continuously drawn in a billet form, and the base metal is discharged. The discharge operation can be performed without stopping the operation, and the operation efficiency does not decrease. Further, since the molten metal is not directly handled, the metal extracting operation can be performed safely. Further, since slag is not mixed and discharged, the layer thickness of the molten slag does not decrease, stable operation can be continued, and work for separating metal and slag is not required.

According to the third aspect of the present invention, even if the extraction nozzle cylinder and the solidified metal piece are fixed to each other, the outer peripheral portion of the solidified metal piece is melted by the solidified metal melting means so that the pinch roller can be fixed. It can be extracted smoothly by the device.

Further, according to the structure of the fourth aspect,
Heating and cooling can be shared by the metal tube coil, and the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a base metal discharging device according to the present invention.

FIG. 2 is a longitudinal sectional view showing a plasma type ash melting furnace provided with the base metal discharging device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace main body 2 Melting chamber 8A Anode torch 8B Cathode torch 21 Base metal discharge device 22 Metal discharge port 23 Extraction nozzle cylinder 24 Metal cooling and heating device 25 Pinch roller device 26 Metal piece cutting device 31 Copper pipe coil 32 High frequency power supply 33 Cooling water Supply device M Base metal SM Solidified metal piece

Claims (4)

[Claims] In discharging a molten base metal increased by a metal mixed in ash which is heated and melted in a furnace main body, a metal is removed from a metal discharge port formed facing a base metal at a bottom of the furnace main body. A method for discharging a base metal of an ash melting furnace, comprising cooling and solidifying a molten metal entering a furnace, continuously extracting the solidified metal piece from a discharge nozzle cylinder, and discharging the molten metal as a solidified metal piece. . 2. A metal outlet opening at the bottom of a furnace main body for housing a molten base metal, an extraction nozzle tube communicating with the metal extraction outlet, and an internal molten metal provided in the extraction nozzle tube. And a pinch roller device capable of holding the solidified metal piece from the extraction nozzle cylinder below the extraction nozzle cylinder and continuously extracting the solidified metal piece. Characterized as a base metal discharge device for ash melting furnaces. 3. A base metal discharge device for an ash melting furnace according to claim 2, wherein said extraction nozzle cylinder is provided with a solidified metal melting means for heating and melting the outer periphery of the solidified metal piece inside. 4. A solidified metal melting means comprising a metal tube coil spirally wound around an outer peripheral portion of an extraction nozzle cylinder and a high-frequency power supply for supplying a high-frequency current to the metal tube coil; 4. The ash melting furnace base metal discharge device according to claim 3, further comprising a metal cooling and heating device integrally provided with a metal cooling means comprising a cooling water supply device for supplying cooling water into the metal tube coil. .