JP2000179829A - Exhaust gas duct of ash melting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a longitudinal duct from being clogged with dust by fitting a scratching body being driven to move up and down to the inner circumferential surface of the duct through a gap and disposing a body penetrating trough the opening of the scratching body when it is moved upward above a longitudinal duct thereby scratching dust. SOLUTION: A scratching body 30 being fitted to the inner circumferential surface 21a of a longitudinal duct 21 through a small gap has a round opening 31 extending in the vertical direction and the outer circumferential fringe part on the lower surface of the scratching body 30 functions as an edge for scratching dust adhering to the inner circumferential surface 21a of the longitudinal duct 21. A penetrating body 35 is secured downward to a cover plate 23. The penetrating body 35 is arranged similarly to the opening 31 of the scratching body 30 and has a diametral dimension being fitted in the opening 31 through a gap and a length long enough to penetrate through the opening 31 and project below the scratching body 30 when it is moved upward. Since the penetrating body 35 penetrate through the opening 31 and scratches dust when the scratching body 30 is moved upward, the opening 31 can be prevented.

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 an ash melting device for melting ash, which is incineration residue generated by incineration of general waste and industrial waste, particularly ash including fly ash (dust). About.

[0002]

2. Description of the Related Art Ash melting is performed to reduce the volume and detoxification of ash. In particular, it is necessary to completely decompose dioxins contained in fly ash. Is completely burned at a temperature of 1000 ° C. or more, and in a cooling process of exhaust gas after burning, particularly 300 to 600
In order to prevent re-synthesis of dioxins, which is referred to as a de novo reaction that rapidly progresses between ℃, the exhaust gas needs to be rapidly cooled to 200 ℃ or less.

However, the cooling of the exhaust gas causes CaCl ₂ , NaCl, KCl, Z volatilized during the melting of the ash.
Chloride such as nCl ₂ precipitates as a solid via droplets, and the molten fly ash component generated during the ash melting process adheres and grows as dust on the inner peripheral surface of the exhaust gas duct, and closes the duct if left unattended . Therefore, the applicant filed Japanese Patent Application Laid-Open
No. 19436, an exhaust gas cooling apparatus for a waste melting furnace in which cooling air is blown from a number of small holes provided in a vertical duct and a scraping body moving close to the inner surface of the vertical duct is moved up and down. Has been proposed.

[0004]

In the above cooling device,
In addition to blowing in cooling air, it also has the advantage of reliably preventing blockage of the duct in that mechanical scraping of dust by the scraping body is also used, but the scraping body itself also has The dust adheres, and depending on the shape of the opening of the scraping body, the opening may be gradually closed by dust accumulated and enlarged by long-term furnace operation. If the dust removal and cleaning of the scraped body is not performed by the maintenance work, the flow resistance to the exhaust gas flowing as a rising flow in the vertical duct increases, so that it becomes difficult to suck and exhaust the exhaust gas and maintain a predetermined furnace pressure. It is possible that the operation of the melting furnace will be hindered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to prevent not only a blockage of a duct but also a blockage of an opening of a scraping body, and an exhaust gas duct of an ash melting apparatus which does not require maintenance of the duct and the scraping body. It is intended to provide.

[0006]

According to the first aspect of the present invention,
A metal vertical duct connected to the exhaust gas port of the ash melting device and provided with a subsequent duct connection port at the top, a cooling fluid chamber provided around the outer peripheral portion of the vertical duct and supplied with a cooling fluid, A scraping body fitted with a clearance to the inner peripheral surface of the vertical duct and having an opening extending in the vertical direction, a lifting drive device for lifting and lowering the scraping body, and And a through body penetrating through the opening of the scraping body.

As described above, the scraping body which is fitted to the inner peripheral surface of the vertical duct with a clearance and is driven to move up and down is provided, and a penetrating body penetrating through the opening of the scraping body when the scraping body rises is provided at the upper part of the vertical duct. Therefore, the dust adhering and accumulating on the inner peripheral surface of the vertical duct is scraped off by the scraping body, and the dust adhering and accumulating near the opening of the scraping body is scraped off by the penetrating body. Blockage due to dust is prevented.

The vertical duct is cooled by the cooling fluid in the cooling fluid chamber, and the exhaust gas flowing through the vertical duct is cooled by the inner peripheral surface of the vertical duct, and precipitates chlorides and the like contained in the exhaust gas in a molten state. The cooling fluid chamber is formed of an air chamber to which cooling air is supplied, and a plurality of small holes are formed in the vertical duct. It is particularly preferable to adopt a configuration in which the cooling air in the air chamber is blown into the vertical duct from the small holes, because the exhaust gas can be more rapidly diluted and cooled to prevent resynthesis of dioxins.

Note that the vertical duct in the present invention does not necessarily need to be erected so as to be directed vertically (vertically) with respect to the horizontal plane, and the particulate dust scraped by the scraping body or the penetrating body opposes the exhaust gas flow. May be arranged in an inclined state with respect to the vertical direction within a range where it falls downward.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, reference numeral 1 denotes a waste melting furnace, which uses incinerated fly ash as waste to be melted, and has a cylindrical space-like melting processing chamber 4 extending vertically in a furnace body 3 fixed on a foundation 2. A lower portion of an oxygen burner 6 attached downward to a furnace lid 5 attached to the furnace body 3 is inserted into the melting chamber 4 and an exhaust gas port 7 communicating with the melting chamber 4 is provided with a furnace lid. The exhaust gas port 7 is connected to an exhaust gas duct 20 which will be described later, and the subsequent duct connection port 22 is connected to a duct 8 which is connected to an exhaust blower via a dust collecting device (not shown). .

The oxygen burner 6 burns the liquid or gaseous fuel F supplied to the fuel supply port 6a with the oxygen supplied to the oxygen supply port 6b.
The incinerated fly ash W supplied together with the air for transport is blown into the fly ash supply port 6c to melt the fly ash. For example, a structure disclosed in Japanese Patent Application Laid-Open No. H8-312938 can be suitably used. . Reference numeral 10 denotes a slag storage unit that stores the molten slag S formed at the bottom of the melting processing chamber 4.
Reference numeral 1 denotes a groove for deriving molten slag extending from the slag storage section 10 toward one side wall of the furnace body 3, formed at the bottom of a side chamber portion 4 a extending to the side of the molten processing chamber 4, A slag port 12 is formed in a portion (outside end of the furnace).

On the other hand, in the exhaust gas duct 20 part, FIG.
As shown in FIG. 3 and FIG. 3, a branch duct-like subsequent duct connection port 22 (see FIG. 3) is formed on the upper part of a cylindrical vertical duct 21 made of metal (heat-resistant steel in this example) having a lower portion connected to the exhaust gas port 7. 1), and the top is closed with a lid plate 23,
An exhaust gas passage is formed, and the outside of the vertical duct 21 is surrounded by an outer cylinder 24 to form an air chamber 25 serving as a cooling fluid chamber.
The vertical duct 21 is fixed to the furnace lid 5 in an upright state by being attached to the top surface of the furnace. Reference numeral 26 denotes a cooling air supply port provided in the outer cylinder 24, which is connected to a cooling air supply device (not shown) such as a blower for supplying room-temperature air. A large number of small holes 27 having a diameter of about 4 to 8 mm are bored.
From the vertical duct 21.

Reference numeral 30 denotes a thick disk-shaped metal scraping body which fits into the inner peripheral surface 21a of the vertical duct 21 with a small clearance (for example, 3 to 10 mm), and has six round holes extending in the vertical direction. With the opening 31, the outer peripheral edge of the lower surface of the scraping body 30 functions as a scraping blade for dust adhered to the inner peripheral surface 21 a of the vertical duct 21. 40 is this scraped body 3
0, the scraping body 30 is fixed to the lower end of a round rod 41 extending vertically through the seal portion 23a of the cover plate 23 and supported by a bracket 42 erected on the cover plate 23. The guide roller 43 guides the rod 41 so as to be able to move up and down, and the arm 47 attached to the upper end of the rod 41 is attached to the piston rod 46a of the air cylinder 46 supported by the bracket 45 attached to the beam 44 fixed to the foundation. It consists of connecting the tips.

On the lower surface side of the cover plate 23, six penetrating members 35 made of round bars are fixed downward. The penetrating body 35 has the same diameter as the opening 31 of the scraping body 30 and has a diameter dimension that fits into the opening 31 with a clearance of about 3 to 10 mm. When the scraping body 30 is raised, it is shown in FIG. Penetrating body 35 penetrates opening 31 so that the lower end surface is scraped body 3
The length is set so as to protrude below the lower surface of the zero. In this example, the rotation of the scraping body 30 about the vertical axis for fitting the opening 31 and the penetrating body 35 is controlled by rotating the arm 47 at the upper end of the rod 41 about the vertical axis by the piston rod 46a. Although the control is performed by restricting, another rotation restricting means such as engaging the arm 47 with a guide extending in the vertical direction may be used.

During operation of the waste melting furnace 1 having the above configuration,
The incineration fly ash W charged into the high-temperature flame of the oxygen burner 6 in the melting processing chamber 4 is melted, and the generated molten slag S is caused to overflow from the slag storage section 10 through the groove 11 to the slag port 12 to continuously discharge slag. At the same time, the exhaust gas generated by the melting process is sucked and exhausted from the exhaust gas port 7 through the vertical duct 21 and the subsequent duct connection port 22 to collect molten fly ash in the exhaust gas. The molten slag flowing out of the slag port 12 is granulated by a granulator (not shown).

The vertical exhaust duct 2
Exhaust gas flowing as an ascending flow in the inside 1 is diluted and cooled by cooling air blown from the small holes 27, and is cooled by the inner peripheral surface 21 a of the vertical duct 21 cooled by cooling air in the air chamber 25. As a result, dust due to chloride precipitation in the exhaust gas adheres and accumulates on the inner peripheral surface 21a, but the scraping body 30 is intermittently or continuously driven up and down by the lifting drive device 40, so that the It moves up and down along the peripheral surface 21a to scrape the dust,
Blockage of the vertical duct 21 is prevented. Scratched dust, some fine powders flow out with the exhaust gas flow,
The granular material falls into the melting processing chamber 4. At this time, since the vertical duct 21 is made of metal, dust attached to the inner peripheral surface 21a can be easily separated by the scraping body 30.

Further, since the scraping body 30 has the opening 31, even if the scraping body 30 is moved up and down during the operation of the furnace, the exhaust gas in the furnace can be sucked and exhausted, and the dust scraping can be performed without any trouble. At this time, the exhaust gas collides with the lower surface of the scraping body 30 and flows through the opening 31. Therefore, dust adheres and accumulates near the opening 31. However, when the scraping body 30 rises, the penetrating body 35 passes through the opening 31. Thus, the dust is scraped off, so that the opening 31 can be prevented from being blocked by dust.

When the cooling air is blown from the small holes 27, for example, the temperature of the exhaust gas at the subsequent duct connection port 22 is detected, and the cooling air supply port 26 is set so that the temperature becomes 200 ° C. or less. By adjusting the amount of cooling air supplied to the exhaust gas, the exhaust gas is rapidly diluted and cooled, so that resynthesis of dioxins can be prevented.

The present invention is not limited to the above example. For example, the opening 31 of the scraping body 30 and the penetrating body 3
The cross-sectional shape of 5 may be various shapes other than the above-mentioned circle. For example, as shown in FIG. 4, an annular portion 30a and a boss portion 30b are connected by four spokes 30c to form a handle-type scraping body 30 having a large aperture ratio and having four fan-shaped openings 31. Can also. This is more preferable because the flow resistance to the exhaust gas can be reduced and the adhesion of dust to the scraped body itself can be reduced. In the drawing, the same parts as those in FIG. 3 are denoted by the same reference numerals.

In the above example, the air chamber 25 is employed as the cooling fluid chamber, and the small holes 2 of the vertical duct 21 are provided.
From the cooling air in the air chamber 25 to the vertical duct 21
Although the exhaust gas blown into the inside was diluted and cooled, if the dilution cooling is unnecessary due to the composition and temperature of the dust in the exhaust gas, the small holes 27 may be omitted, and as a cooling fluid chamber, A water jacket to which cooling water is supplied may be used. Further, a water spray mist may accompany the cooling air.

The present invention is also applicable to exhaust gas ducts of various types of ash melting devices, such as an arc heating type or a plasma heating type, in addition to the above-described burner heating type ash melting device.

[0022]

As described above, according to the present invention,
The dust that adheres and accumulates on the inner peripheral surface of the vertical duct is scraped off by the scraping body driven up and down, and the dust that adheres and accumulates near the opening of the scraping body is scraped off by the penetrator provided at the top of the vertical duct. As a result, it is possible to prevent the opening of the scraping body as well as the vertical duct from being blocked, and it is not necessary to maintain the vertical duct and the scraping body.

In addition to the above effects, according to the second aspect of the present invention, the exhaust gas is rapidly diluted and cooled by blowing cooling air from the small holes of the vertical duct to re-synthesize dioxins. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a waste melting furnace showing an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a diagram corresponding to FIG. 3, showing another example of the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Waste melting furnace, 5 ... Furnace lid, 7 ... Exhaust gas port, 20 ... Exhaust gas duct, 21 ... Vertical duct, 21a ... Inner peripheral surface, 22 ...
Subsequent duct connection port, 23 lid plate, 24 outer cylinder, 25 air chamber, 26 cooling air supply port, 27 small hole, 3
0: scraping body, 31: opening, 35: penetrating body, 40: lifting drive, 41: rod, 46: air cylinder.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroshi Goto 56, Saigo, Ichinomiya-shi, Aichi Ozai Ogo-shi F-term (reference) 3K061 NB03 NB08 PB15 QA11 QA13 4D002 AA21 BA12 BA13 BA14 CA20 DA70 HA06 4D004 AA36 AB07 AC05 CA24 CA29 CA32 CA45 CB33 CB34 CB43 CC02

Claims (2)

[Claims] 1. A metal vertical duct connected to an exhaust gas port of an ash melting device and having a subsequent duct connection port at an upper part thereof, and a cooling pipe provided to surround an outer peripheral portion of the vertical duct and supplied with a cooling fluid. A fluid chamber, a scraping body fitted with a clearance to the inner peripheral surface of the vertical duct and having an opening extending in the vertical direction, a lifting drive device for driving the scraping body up and down, and a downwardly facing upper part of the vertical duct. A flue gas duct for an ash melting device, comprising: a penetrating member that projects and penetrates through the opening of the scraping member when ascending. 2. The cooling fluid chamber comprises an air chamber to which cooling air is supplied. A plurality of small holes are formed in the vertical duct, and the cooling air in the air chamber is supplied from the small holes. 2. An exhaust gas duct for an ash melting device according to claim 1, wherein said exhaust gas is blown into a vertical duct.