JPH08178238A - Ash melting furnace - Google Patents

Abstract

PURPOSE: To perform reliable complete combustion in a re-combustion chamber by a method wherein in the re-combustion chamber of an ash melting furnace, a burner for combustion is arranged, secondary air is fed in the discharge direction of exhaust gas and mixed wit high efficiency. CONSTITUTION: A plurality of feed nozzles 21 through which secondary air is fed to an upper part are arranged at intervals of a given distance in the direction of width in the throttle part 4d of a peripheral wall body in which a discharge port 10 is formed, and an air feed source is connected to a feed nozzle 21 through a header 22. Incinerated ash charged in a melt chamber 13 through a charge port 7 by means of an ash feed hopper 8 and by a pusher 9 is heated and molten by plasma arc. Exhaust gas generated in the melt chamber 3 enters a re-combustion chamber 12 through the discharge port 10 and re-burnt by a burner 14 for combustion. In this case, secondary air is fed in the discharge direction of exhaust gas through a feed nozzle 21 arranged in such a state to insert a throttle part 4d therein, and exhaust gas and secondary air are mixed together with high efficiency and complete combustion in the re-combustion chamber 12 and complete combustion in the re-combustion chamber 12 is reliably executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses incinerator ash discharged from a refuse incinerator or the like, or fly ash contained in combustion exhaust gas to generate electric energy (for example, plasma, electric arc,
Joule heat, etc.) and is related to an ash melting furnace that melts by heating.

[0002]

2. Description of the Related Art As this type of ash melting furnace, for example, a plasma ash melting furnace having a plasma electrode made of carbon is used.

In this plasma type ash melting furnace, when the furnace is in an oxidizing atmosphere, an inert gas such as argon gas or nitrogen gas is used as a plasma working gas in order to prevent the consumption of the electrodes. Heating and melting are performed in a reducing atmosphere in the furnace.

Therefore, exhaust gas containing a large amount of combustible gas such as CO, H ₂ and hydrocarbon is generated. Therefore, conventionally, as shown in FIG.
The exhaust gas discharged from the exhaust port 53 through the exhaust port 53 was introduced into the re-combustion chamber 54 provided in the gas exhaust path downstream thereof, and completely burned by the combustion burner 55.

The combustion burner 55 is located slightly below the discharge port 53 for the molten slag S and the discharge port 53.
The molten slag S falling from the discharge port 53 while heating the molten slag S, igniting the combustible gas in the exhaust gas from the melting chamber 52, and further reburning chamber 54.
The complete combustion was performed by the secondary air blown from the secondary air nozzle 56 provided on the downstream side of the.

[0006]

According to the structure of the ash melting furnace, the combustible gas in the exhaust gas from the melting chamber 52 and the secondary air are not sufficiently mixed, especially when the exhaust gas amount increases. In some cases, complete combustion in the re-combustion chamber 54 may not be possible, and due to volume expansion accompanying combustion in the re-combustion chamber 54, the oxidizing atmosphere gas in the re-combustion chamber 54 flows back into the melting chamber 52. The inside of the melting chamber 52 becomes an oxidizing atmosphere,
Therefore, there is a possibility that the electrode wear may be accelerated, and that the residence time of the gas needs to be lengthened to burn the combustible gas, which causes a problem that the volume of the re-combustion chamber 54 must be increased.

Therefore, an object of the present invention is to provide an ash melting furnace which can solve the above problems.

[0008]

In order to solve the above problems, the ash melting furnace of the present invention is provided with a slag extracting chamber at a position corresponding to the discharge port of the molten slag in the melting chamber in the furnace body, An exhaust gas re-combustion chamber is provided above the slag extraction chamber, a combustion burner is provided on the side wall portion of the re-combustion chamber, and secondary air is supplied to the throttle portion of the peripheral wall body forming the discharge port. A nozzle is provided.

[0009]

According to the above construction, since the secondary air is supplied toward the exhaust gas discharge direction, the exhaust gas and the secondary air are efficiently mixed, and therefore complete combustion in the re-combustion chamber is surely performed. .

Further, since the re-combustion is carried out immediately after it comes out from the discharge port and the mixing / combustion region moves in the exhaust gas discharge direction as compared with the conventional case, the re-combustion chamber can be made compact.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a plasma-type ash melting furnace for heating and melting incineration ash (or fly ash) discharged from a refuse incinerator to reduce its volume.

This plasma type ash melting furnace 1 has a furnace body 4 in which a melting chamber 3 filled with a molten base metal 2 is formed.
And two plasma torches (anode, cathode) 5 and 6 inserted into the melting chamber 3 from the upper wall portion 4a of the furnace body 4, and the ash formed on the front wall portion 4b of the furnace body 4. An ash supply hopper 8 and a pusher 9 for supplying incineration ash into the melting chamber 3 through a port 7, and a discharge port (a discharge port) for the molten slag A formed in the narrowed portion 4d of the rear wall portion 4c of the furnace body 4. Also called) 1
A slag extraction chamber 11 formed on the 0 side and corresponding to the discharge port 10, a re-combustion chamber 12 formed above the slag extraction chamber 11, and both chambers 11 and 12 are formed. A water granulation pit 16 in which a combustion burner 14 provided in a side wall portion 13a facing the discharge port 10 of the wall body 13 and a conveyor 15 for slag discharge and arranged below the slag extraction chamber 11 are arranged. It consists of and.

Further, a supply nozzle (nozzle part) 21 for supplying (spraying) secondary air is provided, for example, in the width direction in the upper part of the narrowed part 4d of the peripheral wall forming the discharge port 10. A plurality of air supply sources (not shown) are connected to each of these supply nozzles 21 via a header 22. Further, each of these supply nozzles 21 is L-shaped when viewed from the side, and the direction of the tip portion thereof is the exhaust gas discharge direction, that is, the re-combustion chamber 1
2 and the slag extraction chamber 11 side.

An exhaust gas outlet 17 is formed in the upper wall portion 13b of the re-combustion chamber 14, and a gas exhaust path (not shown) for exhausting exhaust gas is formed in the outlet 17. Are connected.

In the above structure, the ash supply hopper 8 and the pusher 9 heat and melt the incineration ash charged into the melting chamber 3 through the charging port 7. Then, the exhaust gas generated in the melting chamber 3 is discharged through the exhaust port 1
0 into the re-combustion chamber 12, where the combustion burner 14
Is reburned by.

At this time, the throttle portion 4d forming the discharge port 10
The secondary air is supplied from the supply nozzle 21 provided through the exhaust gas toward the exhaust gas discharge direction, that is, toward the re-combustion chamber 12 and the slag extraction chamber 11 side. Therefore, the exhaust gas and the secondary air are efficiently supplied. Re-combustion chamber 1 because it is mixed
Complete combustion in 2 is surely performed.

Further, since the combustion is performed from the time when it comes out from the discharge port 10 and the mixing / combustion region moves to the upstream side, that is, in the exhaust gas discharge direction, compared with the conventional case, the re-combustion chamber 12 is compared with the conventional case. Even when it is made compact (when part a in FIG. 8 is eliminated), it is possible to secure a sufficient gas retention time for combustion of the combustible gas, and the slag extraction portion is formed by the combustion immediately after the discharge port 10. However, since it is heated, the slag can be extracted smoothly.

Further, the supply of the secondary air prevents the backflow of the oxidizing atmosphere gas from the reburning chamber 12 into the melting chamber 3, so that the consumption of the plasma torches 5, 6 serving as electrodes can be suppressed. .

The molten slag S discharged from the discharge port 10 is dropped into the water granulation pit 16, where it is finely crushed by cooling water and taken out by the conveyor 15.

By the way, in the above embodiment, the discharge port 1
Although no stepped portion was provided in the throttle portion 4d forming 0, as shown in phantom lines in FIG. 2 and FIG. 3, for example, the upper surface portion of the throttle portion 4d on the melting chamber 3 side of the supply nozzle 21 is provided inside. You may form the protrusion part 4e which protrudes.

By forming the protrusion 4e in this manner, the supply nozzle 21 can be protected from being damaged by the exhaust gas. Of course, the size of the protruding portion 4e is sized so as to protect the supply nozzle 21, and, for example, when the supplying nozzle is provided on the side surface of the throttle portion 4d, the protruding portion has a side surface. Provided in the department.

As a matter of course, the opening area of the throttle portion 4d itself, that is, the area of the discharge port 10 is the area necessary for the passage of the exhaust gas, so that the opening area is narrowed by the protrusion 4e in the drawing. Although it is illustrated in
The peripheral wall surface of the throttle portion 4d on the discharge side (on the side opposite to the melting chamber) provided with the supply nozzle 21 is expanded.

By the way, in the above embodiment, as the nozzle portion provided in the throttle portion 4d, the supply nozzle 2 having an L-shape in a side view whose end portion is bent so as to face the exhaust gas discharge direction.
1 is shown, for example, as shown in FIGS. 4 and 5, as the nozzle portion, an oblique nozzle hole 31 is formed in the throttle portion 4d so as to face the exhaust gas discharge direction, and the supply nozzle 32 is provided in the nozzle hole 31. It is also possible to insert.

The supply nozzles 21 and 32 described above are
Although it is arranged above the narrowed portion 4d, for example, as shown in FIGS. 6 and 7, nozzle holes 42 into which the supply nozzle 41 is inserted can be provided on both sides of the narrowed portion 4d as the nozzle portion. Nozzles may be provided on both the upper and side portions. Of course, the direction of the secondary air supplied from the supply nozzle or nozzle hole provided in the side part,
It corresponds to the exhaust gas emission direction.

As described above, when the supply nozzles or the nozzle holes are provided in both the upper part and the lateral part, the backflow of air can be prevented more completely.

[0026]

As described above, according to the configuration of the present invention, since the secondary air is supplied in the exhaust gas discharge direction, the exhaust gas and the secondary air are efficiently mixed, and therefore complete combustion in the re-combustion chamber is achieved. Is surely done.

Further, since re-combustion is performed immediately after it comes out from the discharge port and the mixing / combustion region moves in the discharge direction as compared with the conventional case, even when the re-combustion chamber is made more compact than the conventional case. In addition, it is possible to secure a sufficient gas retention time for burning the combustible gas.

[Brief description of drawings]

FIG. 1 is a sectional view of a plasma-type ash melting furnace according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of the ash melting furnace of the same example.

FIG. 3 is a view as viewed in the direction of arrows AA in FIG. 2;

FIG. 4 is a sectional view of an essential part of an ash melting furnace according to another embodiment of the present invention.

5 is a view taken along the line BB of FIG.

FIG. 6 is a sectional view of an essential part of an ash melting furnace according to another embodiment of the present invention.

FIG. 7 is a view taken along the line CC of FIG.

FIG. 8 is a sectional view of a conventional plasma-type ash melting furnace.

[Explanation of symbols]

 1 Plasma Ash Melting Furnace 3 Melting Chamber 4 Furnace Main Body 4d Throttling Port 10 Discharge Port 11 Slag Extracting Chamber 12 Recombustion Chamber 14 Combustion Burner 21 Supply Nozzle 31 Nozzle Hole 32 Supply Nozzle 41 Supply Nozzle 42 Nozzle Hole

Claims (2)

[Claims] 1. A slag extraction chamber is provided at a position corresponding to a molten slag discharge port in a melting chamber in a furnace body, and an exhaust gas re-combustion chamber is provided above the slag extraction chamber for re-combustion. An ash melting furnace characterized in that a combustion burner is provided on a side wall portion of the chamber, and a nozzle portion for supplying secondary air is provided at a throttle portion of a peripheral wall body forming the discharge port. 2. The ash melting furnace according to claim 1, wherein the secondary air is supplied to the nozzle portion in the exhaust gas discharge direction.