JPH05126331A - Discharged gas duct of melting furnace - Google Patents

Abstract

PURPOSE:To prevent trouble of closing of a discharging gas duct by a method wherein an inner circumference of the discharging gas duct of a melting furnace is provided with a porous member, an air chamber is formed between the porous member and the duct, and a gas supplying nozzle to be communicated with the air chamber is arranged at the duct. CONSTITUTION:A heat-resistant porous member 2 such as foamed ceramics capable of ventilation is disposed inside a discharging gas duct 1 of a melting furnace. Gas 9 such as air is fed from the porous member 2 into the duct 1, gaseous substance of low boiling point near the porous member 2 is rapidly cooled, solidified and purged and at the same time dispersed dust contained in the discharged gas is purged. In this case, a gas supplying nozzle 4 is fixed in a tangential direction of the duct 1 and then the air can be uniformly blown into the air chamber 3 in a circulated flow. With such an arrangement, it is possible to prevent a trouble of closing of the discharging gas duct 1 caused by fixing or accumulation of gaseous substance of low boiling point or dispersed dust in the discharged gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas duct of a melting furnace, and more particularly to an exhaust gas duct of an incinerator ash melting furnace applied as a treatment facility for reducing the volume and detoxifying the incinerated ash.

[0002]

2. Description of the Related Art Recently, a melting and solidifying method by high temperature treatment is being adopted as a volume reduction and detoxification treatment method for incinerated ash, but low melting point substances contained in the incinerated ash are vaporized in a gaseous state and cooled. The trouble of closing the furnace outlet duct due to the sticking to the furnace outlet duct or the adhesion and deposition of the scattering duct on the furnace outlet duct makes continuous operation impossible, which is a bottleneck for this type of high temperature plant. However, the exhaust gas duct of the conventional melting furnace is as shown in FIG. 7, and it is only a refractory and heat insulating material having a fire and heat insulating structure. There is no example.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned state of the art, the present invention is based on the adhesion and deposition of low boiling point condensable gas and scattered dust entrained in exhaust gas to the furnace outlet duct in an incinerator ash melting furnace. The present invention intends to provide an exhaust gas duct of an incinerator ash melting furnace capable of actively avoiding clogging troubles and performing stable continuous operation.

[0004]

According to the present invention, (1) a porous ceramic body made of foam ceramic is provided on the inner circumference of an exhaust gas duct of a melting furnace, and a wind chamber is formed between the porous body and the duct. An exhaust gas duct for a melting furnace, characterized in that a gas supply nozzle communicating with the wind chamber is provided in the duct.

(2) The exhaust gas duct of the melting furnace according to claim 1, wherein the gas supply nozzle is provided tangentially to the wind chamber.

(3) An exhaust gas duct for a melting furnace according to claim 1, characterized in that a gas distributing means is provided at a tip outlet of the gas supply nozzle. Is.

[0007]

The furnace exhaust gas of the melting furnace contains gaseous substances having a low melting point in addition to scattered dust. Then, depending on the temperature and flow rate conditions of the furnace outlet gas, dust may be accumulated on the inner wall of the duct, and low boiling point gaseous substances may be condensed and adhered to cause clogging trouble, which hinders stable continuous operation. ing.

The main reason for this is that the low boiling point gaseous substance undergoes a phase change with a temperature drop, and at this time, a liquid phase intervenes. Therefore, in the present invention, a heat-resistant porous body such as a foamed ceramic is disposed inside the exhaust gas duct, and a gas such as air is fed into the duct from the porous body to form a low boiling point gas near the porous body. Rapidly cooling substances,
Not only solidification and purging, but also purging scattered dust in exhaust gas to prevent clogging troubles of exhaust gas duct due to adhesion and accumulation of low boiling point gaseous substances and scattered dust in exhaust gas Is.

[0009]

EXAMPLE An example of an exhaust gas duct of a melting furnace according to the present invention will be described with reference to FIGS. 1 is a vertical cross-sectional view of the exhaust gas duct, FIG. 2 is a view taken along the line AA of FIG. 1, and FIG. 3 is a view taken along the line BB of FIG.

In FIGS. 1 to 3, 1 is a duct (casing), 2 is a heat-resistant porous body such as foam ceramic (hereinafter referred to as porous body) that can be aerated, 3 is a wind chamber, and 4 is a gas supply such as air. Nozzle, 5 is a porous body pressing flange, 6 is a porous body fixing metal fitting, 7 is inlet exhaust gas, 8 is outlet exhaust gas, and 9 is gas such as air.

The gas 9 is sent from the gas supply nozzle 4 into the wind chamber 3 and is injected into the duct 1 from the porous body 2 to purge low-boiling substances and scattered dust, so that clogging of the duct can be prevented. .. In this example, FIG.
Where L / D = 1 to 10 and the flow rate of the gas supplied through the porous body 2 is relative to the flow rate of the high temperature gas to be cooled.
By operating in the range of 0.05 to 2.0, there is no trouble such as adhesion, sticking, and deposition on the inner wall of the exhaust gas duct for melting furnace exhaust gas containing scattered dust and low boiling point gaseous substances. The stable continuous operation was possible.
The range of the velocity ratio of the jet gas is slightly different depending on the target gas, the type and concentration of the low boiling point substance and the scattered dust, and depending on the gas to be treated, it is possible to prevent the above trouble by sending a very small amount. ..

Hereinafter, as another embodiment, an embodiment in which the gas supply nozzle 4 is improved so as to have a function of equalizing the jetting speed on the entire surface of the porous body 2 for each section is shown in FIGS. 5 and FIG. These drawings correspond to the view taken along the line CC of FIG.

FIG. 4 shows a gas supply nozzle 4 mounted in the tangential direction of the duct 1 so that the air can be uniformly fed in a swirl flow into the wind chamber 3. FIG. An air distribution pipe 10 is provided, and in FIG. 6, a porous body distributor 11 is attached to the tip of the gas supply nozzle 4, whereby the flow velocity of gas ejected from the porous body 2 for each section is increased. Can be made uniform, and
Similar to the embodiment described with reference to FIG. 3, stable continuous operation was possible. In addition, in FIG. 5 and FIG. 6, 12 is a guide tube of the gas supply nozzle 4.

As the material of the heat resistant porous body 2, cordierite, alumina-containing cordierite, alumina, silicon carbide, silicon nitride, or a porous sintered body of other metal (such as SUS) can be used.

[0015]

INDUSTRIAL APPLICABILITY According to the present invention, in an exhaust gas duct at the exit of a furnace for treating high temperature gas containing scattered dust and low boiling point gaseous substances in the exit exhaust gas such as in a melting furnace, these deposits, condensation sticking, adhesion, etc. It is possible to provide an exhaust gas duct for a melting furnace that prevents clogging troubles and that enables stable and continuous operation, and its industrial effect is remarkable.

As a side effect, by supplying air for cooling and purging, unburned gas (CO etc.)
It is possible to promote combustion of the.

[Brief description of drawings]

FIG. 1 is an exhaust gas duct and a longitudinal sectional view of an embodiment of the present invention.

FIG. 2 is a view on arrow AA of FIG.

FIG. 3 is a view taken along the line BB of FIG.

FIG. 4 is an explanatory view of another embodiment of the gas supply nozzle of the present invention.

FIG. 5 is an explanatory view of another embodiment of the gas supply nozzle of the present invention.

FIG. 6 is an explanatory view of another embodiment of the gas supply nozzle of the present invention.

FIG. 7 is an explanatory diagram of one mode of an exhaust gas duct of a conventional melting furnace.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Gota 12 Nishiki-cho, Naka-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries, Ltd. Yokohama Works

Claims (3)

[Claims] 1. A gas supply nozzle which is provided with a porous body made of foam ceramic on the inner circumference of an exhaust gas duct of a melting furnace and which is permeable to air, forms a wind chamber between the porous body and the duct, and communicates with the wind chamber. An exhaust gas duct for a melting furnace, wherein: 2. An exhaust gas duct for a melting furnace according to claim 1, wherein the gas supply nozzle is provided tangentially to the wind chamber. 3. An exhaust gas duct for a melting furnace according to claim 1, wherein a gas distribution means is provided at a tip outlet of the gas supply nozzle.