JP3071377B2 - Method and apparatus for supplying fly ash to a plasma type ash 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 a method and an apparatus for supplying fly ash to a plasma type ash melting furnace, which feeds fly ash entrained by waste gas from a refuse incinerator and trapped by a bag filter or the like.

[0002]

2. Description of the Related Art Conventionally, incinerated ash discharged from a refuse incinerator is supplied to an ash melting furnace for the purpose of volume reduction and detoxification, and is heated and melted in a high-temperature atmosphere of 1400 to 1500 ° C. to form molten slag. Water cooled and reused or discarded as granulated slag. By the way, in the past, this incineration ash was mixed with fly ash discharged along with the exhaust gas and captured by a bag filter, etc., and then charged into an ash melting furnace.However, fly ash contains many harmful heavy metals. Therefore, from the viewpoint of safety, it is being regulated that only fly ash is melted independently.

[0003]

The incinerated ash is supplied from the ash supply hobber into the melting furnace by an ash pusher or a screw feeder. However, fly ash has an extremely small particle size and contains almost no moisture. However, it is extremely difficult to use a ash pusher or a screw feeder to put the material into the melting furnace, and even if it can be put into the furnace, a large proportion of the ash is scattered without melting in the furnace, accompanied by exhaust gas, and discharged. Therefore, when only fly ash is put into the melting furnace with a pusher, it is necessary to add water and granulate in advance.

The present invention solves the above-mentioned problems, and provides a plasma type ash melting furnace which can be supplied to a plasma type ash melting furnace without granulating fly ash before charging and can be reliably melted. It is an object to provide a fly ash supply method and apparatus.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method in which ash is charged onto a conductor which has been charged at the bottom of a melting chamber and has been melted, and an electrode provided in the melting chamber has A fly ash supply method of supplying fly ash to a plasma type ash melting furnace that melts ash by a plasma arc generated between an electrode and a conductor by supplying a plasma working gas while supplying power ,
When the fly ash is fed into the plasma working gas supply hole formed in the electrode and is blown onto the conductor together with the plasma working gas, the supply amount of the fly ash is adjusted by the supply amount of the plasma working gas.
It is controlled by

[0006]

[0007] A plasma working gas supply hole is formed in the electrode provided in the melting chamber, the plasma working gas supply hole being opened at the tip, and the plasma working gas is fed into the plasma working gas supply hole .
A gas inner pipe is provided, and the discharge of the fly ash feeder is
Connect the pipe and the gas inner pipe and its outer periphery
Adjust the supply amount of plasma working gas to the gas passage
The gas supply amount adjusting means is provided .

[0008] Further, the melting chamber having the above-mentioned structure is a single torch type in which an anode is connected to a conductor and one cathode electrode is installed, or a twin torch type in which a pair of anode and cathode electrodes are installed. This is a multi-type torch type in which a plurality of anode electrodes are provided on one cathode electrode.

[0009]

According to the above construction, the fly ash sent from the fly ash feeder to the plasma working gas supply hole is preheated in the high temperature plasma torch accompanied by the plasma working gas and then ionized at a very high temperature. Since it is blown onto the base metal through the gas, the fly ash of fine particles is reliably melted and captured by the molten slag, and can be melted without being separated and suspended. Therefore, it is not necessary to granulate the fly ash before charging the fly ash into the ash melting chamber.

Further, since a gas inner tube is provided in the plasma working gas supply hole and fly ash is fed into the gas inner tube, the supply amount of the plasma working gas is adjusted in a passage portion on the outer periphery of the gas inner tube. This makes it possible to control the total supply amount of the plasma working gas regardless of the amount of fly ash supplied.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ash melting furnace according to the present invention will be described below with reference to the drawings. This embodiment is a twin torch type plasma type ash melting furnace having two electrodes 2A and 2B of a cathode and an anode in a melting chamber 1 as shown in FIG.
An ash supply port 3 for supplying incinerated ash Ab discharged from the refuse incinerator is formed at one end of the melting chamber 1. It is configured to supply to.

At the bottom of the melting chamber 1, a base metal 6, which is an example of a conductor, is charged and melted, and the electrodes 2A and 2A are melted.
The plasma arc P formed between B and the base metal 6 melts the incinerated ash Ab and fly ash Af captured by a bag filter or the like accompanying the exhaust gas in the refuse incinerator. The other end of the chamber 1 is provided with a slag outlet 7 for discharging the molten slag S to a slag cooling chamber 8 via a discharge weir 7a.

On the top wall 1a of the melting chamber 1, two electrodes 2
A and 2B are vertically suspended at a predetermined interval, and a high-voltage power supply 13 is connected to these electrodes 2A and 2B to supply melting power. Further, plasma working gas supply holes 9A and 9B for supplying, for example, nitrogen gas, which is an example of a plasma working gas, are formed in the axial center portions of the electrodes 2A and 2B, respectively.
A gas supply pipe 12 connected to a gas cylinder 10 and having regulating valves 11A and 11B interposed therebetween is connected thereto.

The fly ash Af is applied to the two electrodes 2A and 2B.
Ash feeders 21 for supplying ash to the melting chamber 1 are provided, and the fly ash discharge pipes 22 are connected to the base ends of the plasma working gas supply holes 9A and 9B or to the tip of the gas supply pipe 12. Have been. As shown in FIG. 1, for example, the fly ash feeder 21 is constituted by a screw feeder 23 having a spiral screw blade 23c that is rotationally driven by a drive motor 23b in a cylindrical casing 23a. A fly ash supply hopper 24 is provided at the fly ash inlet at the base end. Therefore, the fly ash Af supplied to the fly ash supply hopper 24 is cut out by a predetermined amount by the screw feeder 23, and is sent out from the discharge pipe discharge pipe 22 to the plasma working gas supply holes 9A and 9B to be accompanied by the nitrogen gas, whereby the fly ash Af is taken out. The ash Af can be sent into the melting chamber 1.

In the above configuration, when the fly ash Af is melted, a voltage is applied to the electrodes 2A and 2B in a state where the base metal 6 is preheated and the base metal 6 is melted, and nitrogen gas is supplied from the gas cylinder 10 to the gas cylinder 10. The base metal 6 is supplied through the supply pipe 12 and the plasma working gas supply holes 9A and 9B.
, A plasma arc P is generated between the electrodes 2A and 2B and the base metal 6. Then, the fly ash feeders 21A and 21B are activated, and the fly ash Af is entrained by the nitrogen gas, and the flow velocity is about 3 to 4 m / sec.
At c, it is fed into the melting chamber 1 through the plasma working gas supply holes 9A and 9B. At this time, the fly ash Af, which is fine and contains almost no water, is preheated in the plasma working gas supply holes 9A, 9B of the high-temperature electrodes 2A, 2B, and in the hottest plasma arc P in the melting chamber 1. Is further heated and melted, and is sprayed on the surface of the high-temperature molten slag S, so that the fly ash Af is surely captured by the molten slag S and hardly scattered in the atmosphere. Also fly ash A
Even if f is slightly scattered, it is naturally settled and melted because the area of the melting chamber 1 is large.

In the above embodiment, the electrode 2A as the cathode is used.
And fly ash feeder 21A to electrode 2B as an anode, respectively.
Although 21B is provided, only one may be provided. FIG. 3 shows another embodiment of the fly ash feeder 31 in which a reducer tube 32 is provided instead of the screw feeder 23.
That is, a reducer pipe 32 is interposed in the gas supply pipe 12, and a T-shaped pipe 34 in which a discharge pipe 33 a of a fly ash supply box 33 with a hopper is connected to a branch hole is provided downstream of the reducer pipe 32. The fly ash Af is configured to be fed by the transfer power of nitrogen gas. According to this embodiment,
The fly ash feeder 31 requires no power, has a very simple configuration, requires less space, is inexpensive, and can be easily added to existing equipment.

FIG. 4 shows another embodiment of the plasma working gas supply hole. That is, the gas inner pipe 42 is disposed at the axial center of the plasma working gas supply hole 41, the discharge pipe 22 of the fly ash feeder 21 is connected to the gas inner pipe 42, and the plasma working gas supply hole 41 is An outer peripheral passage portion 41a through which only the plasma working gas flows, a plasma working gas and fly ash A
and an inner passage portion 41b through which f flows. The gas supply pipes 43A and 43B connected to the outer passage 41a and the inner passage 41b are provided with flow control valves 44A and 44B, respectively, which are examples of gas supply control means.

Therefore, the supply amount of fly ash Af can be controlled by adjusting the flow control valve 44B of the gas supply pipe 43B connected to the inner passage 41b, and the gas connected to the outer passage 41a can be controlled. By adjusting the flow control valve 44A of the supply pipe 43A, the supply amount of the plasma working gas can be controlled regardless of the supply amount of the fly ash Af.

FIG. 5 shows another plasma ash melting furnace.
a, one cathode 52A is disposed on the bottom wall 1a.
b shows a single torch type plasma ash melting furnace in which the positive electrode 52B in contact with the base metal 6 is provided. This cathode 52A is provided with a fly ash feeder 21 having the same configuration as that of the above-described embodiment.
3 into the furnace.

FIG. 6 shows one negative electrode 6 in the melting chamber 61.
An embodiment of a multi-type torch type plasma type ash melting furnace in which two or more anodes 62B are provided for 2A is shown. In the drawing, the fly ash feeder 21 having the same configuration as that of the above-described embodiment is disposed in the plasma working gas supply holes 63 of the respective electrodes 62A and 62B, but only an arbitrarily selected electrode may be used.

[0021]

As described above, according to the present invention, fly ash sent from the fly ash feeder to the plasma working gas supply hole is preheated in the high temperature plasma torch together with the plasma working gas. After that, since it is blown onto the base metal through an extremely high temperature ionized gas, the fly ash of fine particles is reliably melted and captured by the molten slag, and can be melted without being separated and suspended. Therefore,
There is no need to granulate the fly ash before charging it into the ash melting chamber.

Further, since a gas inner tube is provided in the plasma working gas supply hole and fly ash is fed into the gas inner tube, the supply amount of the plasma working gas is adjusted in a passage portion on the outer periphery of the gas inner tube. This makes it possible to control the total supply amount of the plasma working gas regardless of the amount of fly ash supplied.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a fly ash feeder of a twin torch type plasma ash melting furnace according to the present invention.

FIG. 2 is a longitudinal sectional view of the plasma type ash melting furnace.

FIG. 3 is a sectional view showing another embodiment of the fly ash feeding device.

FIG. 4 is a longitudinal sectional view showing another embodiment of the plasma working gas supply hole of the same electrode.

FIG. 5 is a longitudinal sectional view of a single torch type plasma type ash melting furnace provided with the fly ash feeding device.

FIG. 6 is a plan sectional view of a multi-type torch type plasma type ash melting furnace provided with the fly ash feeding device.

[Explanation of symbols]

 Af Fly ash S Molten slag 1 Melting furnace 1a Top wall 2A, 2B Electrode 6 Base metal (conductor) 9A, 9B Plasma working gas supply hole 12 Gas supply pipe 21 Fly ash feeder 22 Fly ash discharge pipe 23 Screw feeder 24 Fly ash supply hopper 31 Fly ash feeder 32 Reducer tube 33 Fly ash supply hopper 34 T-shaped tube 41 Plasma working gas supply hole 41a Outer peripheral passage 41b Inner passage 42 Gas inner tubes 43A, 43B Gas supply tubes 44A, 44B Flow control valve 52A Negative electrode 52B Positive electrode 53 Plasma working gas supply hole 61 Melting chamber 62A Negative electrode 62B Positive electrode 63 Ionized gas supply hole

──────────────────────────────────────────────────続 き Continuing on the front page (72) Kunio Sasaki, Inventor 5-3-28 Nishikujo, Konohana-ku, Osaka-shi, Japan Within Hitachi Zosen Corporation (72) Inventor Yoshitoshi Sekiguchi 5-chome, Nishikujo, Konohana-ku, Osaka-shi, Osaka No. 3-28 Inside Hitachi Zosen Corporation (72) Inventor Toshiro Sakata 5-28 Nishikujo, Konohana-ku, Osaka-shi, Osaka Prefecture Inside of Hitachi Zosen Corporation (72) Inventor Hiroshi Kosaka West, Konohana-ku, Osaka-shi, Osaka No. 5-28, Kujo, Hitachi Zosen Corporation (56) References JP-A-6-42724 (JP, A) JP-A-53-20648 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23G 5/00 115 F23G 5/00 ZAB F23G 5/10 ZAB F23J 1/00 H05B 7/18

Claims (3)

(57) [Claims] An ash is charged onto a conductor that has been charged and melted at the bottom of a melting chamber, and power is supplied to an electrode provided in the melting chamber and a plasma working gas is supplied to connect the electrode with the conductor. A fly ash supply method in which fly ash is supplied to a plasma ash melting furnace in which ash is melted by a plasma arc generated therebetween, wherein the fly ash is supplied to a plasma working gas supply hole formed in an electrode and a plasma working gas is supplied. by entrained upon blown onto the conductor, the supply amount adjustment of fly ash in the supply amount of the plasma working gas
A method for supplying fly ash to a plasma type ash melting furnace, characterized by more control . 2. An electrode provided in a melting chamber is provided with a plasma working gas supply hole opening at the tip, and a gas through which a plasma working gas is fed into the plasma working gas supply hole .
An inner pipe is provided, and the discharge pipe of the fly ash feeder is connected to this gas inner pipe.
Connect the gas inner pipe and the outer peripheral gas outside
Adjust the supply amount of plasma working gas to the passage
An apparatus for supplying fly ash to a plasma type ash melting furnace, comprising a gas supply amount adjusting means . 3. The melting chamber may be a single torch type in which an anode is connected to a conductor and one cathode electrode is installed, or a twin torch type in which a pair of anode and cathode electrodes are installed. 3. The fly ash supply device for a plasma type ash melting furnace according to claim 2, wherein the cathode electrode is a multi-type torch type in which a plurality of anode electrodes are provided.