JPH08290078A - Dust collector for flue gas - Google Patents

Abstract

PURPOSE: To provide a dust collector for flue gas in which the recovery efficiency of soot and dust into a dust box is increased greatly by a simple constitution and also smoke dissipation effect is improved based on increase of heat insulating property of a swirl current generation cylinder. CONSTITUTION: A swirl current generation cylinder 2 is integrally provided in the upper end of the lower flue gas cylinder 1. The swirl current generation cylinder 2 is constituted of annular space 3, a guide cylinder 2b, an internal cylinder 4 and a plurality of tilting guide blades 5 interposed between the internal cylinder 4 and the swirl current generation cylinder 2. The upper flue gas cylinder 6 is arranged in the upper part of the swirl current generation cylinder 2. A cover 7 is arranged, so that annular space 8 and annular space 9 are formed. A dust separation cylinder 10 is arranged so as to be made eccentric on one side for the center. A discharge port 12 of dust is provided in the lower part of a guide cylinder 11. The lower introduction port 16a of an exhaust pipe 6 is made eccentric and penetrates the top face 10a of the dust separation cylinder 10 having wide area and is arranged near to annular space 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas dust removing device for preventing environmental pollution by separating and collecting soot dust contained in flue gas from a heat generating engine such as an incinerator or a boiler.

[0002]

2. Description of the Related Art Many proposals have been made so far in order to prevent the scattering of soot, sparks, and combustion debris in flue gas. The most common method is to attach a wire mesh to the tip of the chimney. However, this method not only hinders the exhaust of the flue gas by causing the wire mesh to be immediately clogged, but also lowers the combustion efficiency, and since the wire mesh is greatly consumed, a sufficient dust removal effect is expected. It cannot be done.

In addition to this, a shower type or, for example, Japanese Patent Publication No.
Although a dust collector using a cyclone disclosed in Japanese Patent Publication No. 17525 is also proposed, it requires power.
There are problems to be solved, such as a decrease in combustion efficiency, a high running cost for repairs, and a troublesome handling.

Therefore, the present applicant has previously proposed a flue gas dust remover shown in FIGS. 4 to 6 (see Japanese Patent Publication No. 63-45255).

In this device, a part of the smoke exhaust tube A is a swirl flow generating tube B having a large diameter, and a bell-shaped inner cylinder C whose upper and lower ends are conically closed inside the swirl flow generating tube B. The annular space D is formed concentrically and is expanded outwardly around the annular space D, and a plurality of inclined guide vanes E are radially attached to the annular space D. Above the inclined guide vanes E, the upper smoke stack A An inverted funnel-shaped guide tube F is projected to face the lower end H to form an annular gap Q, and an upward annular groove G is formed between the swirl flow generation tube B and the inner wall of the swirl flow generation tube B so that the smoke exhaust tube A has Lower edge H
A downward annular groove J is formed between the swirl flow generation cylinder B and the upper end of the swirl flow generation cylinder B, and a dust separation cylinder K is concentrically provided outside the swirl flow generation cylinder B. Are communicated with each other through the exhaust port L provided in the swirl flow generating cylinder wall of the annular groove G, the exhaust pipe M is attached to the upper part of the dust separation cylinder K, and this is drawn into the smoke exhaust pipe A so that the smoke exhaust pipe A has the center thereof. A dust box N is provided at the lower end of the dust separation cylinder K so as to open upward. Incidentally, P is a barrier plate which is provided so that soot and dust sucked from the discharge port L do not flow upward and are not sucked into the exhaust pipe M as they are.

The operation of this device will be described. The soot and dust containing the fire powder, combustion dust, and the like that have risen in the smoke exhaust tube A pass through the inclined guide vanes E in the swirl flow generation tube B and become a swirl flow. Then, the sparks and combustion debris having a large specific gravity are drawn outward by the centrifugal force and ascend while swirling along the inner surface of the inverted funnel-shaped guide cylinder F. Since the guide tube F has an inverted funnel shape and has a diameter that decreases as it goes upward, the swirling speed of smoke is accelerated. Therefore, the sparks and combustion debris that have risen along the inner surfaces of the swirl flow generation cylinder B and the guide cylinder F are blown outward from the annular gap Q by the centrifugal force, are drawn into the annular groove G, and are discharged. It falls from L into the dust separation cylinder K. A part of the sparks and combustion debris blown off by the centrifugal force rises as a swirl flow along the upper end of the swirl flow generation cylinder B, but is blocked by the lower end H of the smoke exhaust pipe A and faces downward. While turning in J, it descends and falls from the discharge port L into the dust separation cylinder K. When the sparks and combustion debris fall into the dust separation cylinder K, they lose their swirling force, fall to the bottom of the dust separation cylinder K, and accumulate in the dust box N.

On the other hand, inside the swirl flow generating cylinder B, the lower end H which faces the guide cylinder F and projects from the upper smoke exhaust tube G as described above.
Due to the existence of the annular gap Q formed by (1) and (2), the flue gas, which is discharged dust and combustion debris outside and passes through the smoke flue A, rises upward. Further, the smoke exhausted together with the fire powder and the combustion dust from the exhaust port L is removed by the dust separating cylinder K as described above, and is discharged into the upper smoke exhaust cylinder A through the exhaust pipe M. . The exhaust pipe M is provided concentrically with the upper smoke exhaust A with its opening facing upward, and the central negative pressure acts on the inside of the exhaust pipe M due to the upward exhaust smoke flow. Becomes Therefore, a negative pressure is also exerted in the dust separation cylinder K communicating with the exhaust pipe M, so that the dust and combustion dust are sucked into the dust separation cylinder K from the discharge port L.

According to this apparatus, a swirl flow is generated in the swirl flow generation cylinder by utilizing the ascending airflow of the smoke exhaust itself, and soot and dust such as sparks and combustion debris are generated by the centrifugal force in the swirl flow generation cylinder. Because it uses the natural law of the airflow, such as guiding the dust to the dust separation tube provided around the to separate the soot and discharging the purified smoke into the smoke stack using the central negative pressure. , No power is required. Therefore, it is possible to expect an effect that it does not break down, maintenance is facilitated, and the life is greatly extended.

[0009]

However, in this device, the discharge port L is not only formed in two places of the annular groove G, but the opening area thereof is not sufficient, so that the bending angle, the spark, Due to centrifugal force, combustion debris has an annular gap Q
Therefore, it is difficult to effectively discharge the sparks and combustion debris to the dust separating cylinder K even if they are efficiently blown outward. Moreover,
Among the exhaust fumes including the sparks and combustion debris blown off by the centrifugal force, those that are blocked by the lower end H of the smoke stack A and swirl in the downward annular groove J descend into the exhaust port L from among them. Although it falls into the dust separation cylinder K, the suction into the dust separation cylinder K is unintentionally suppressed because the opening of the discharge port L is small. Therefore, there is a problem that the efficiency of collecting the dust in the dust box N is insufficient.

In addition, the dust separating cylinder K is provided with an inclined surface K for guiding the sparks and combustion debris that have naturally fallen to the dust box N.
Although a is formed, its inclination angle is set to approximately 30 degrees with respect to the horizontal plane, so even if the bending angle, sparks, and combustion debris fall freely on the inclined surface Ka, it easily slips onto the dust box N. It doesn't fall. Therefore, on the inclined surface Ka, sparks,
There is also a problem that the dust collection efficiency in the dust box N is insufficient because only the combustion debris is accumulated.

Further, since the temperature of the flue gas given the swirl flow in the swirl flow generation cylinder B is likely to drop, the smoke exhaust pipe A
There is also a problem in that the combustion efficiency in the case becomes low and the smoke eliminating effect is poor.

Therefore, the object of the present invention is to dramatically improve the efficiency of collecting soot and dust in a dust box with a simple structure, and to improve the heat retention of the swirl flow generating cylinder to eliminate smoke. An object of the present invention is to provide a flue gas dust removal device that can also improve the above.

[0013]

SUMMARY OF THE INVENTION Therefore, in order to achieve the above-mentioned object, the present invention provides a lower smoke stack, a swirl flow generating cylinder continuous to the upper end of the lower smoke stack, and a swirl flow generating cylinder above the swirl flow generating cylinder. The upper smoke exhaust tube arranged through a predetermined space, and at least the swirl flow generating cylinder and the upper smoke exhaust tube line were hermetically enclosed and bent, and the diameter was reduced to the lower side through an inclined surface. A dust separation cylinder provided with a dust discharge port, an exhaust pipe communicating the dust separation cylinder and the upper smoke exhaust pipe, and a dust box detachably attached to the dust discharge port of the dust separation cylinder,
Inclination angle θ ₁ of the inclined surface of the dust separating cylinder with respect to the horizontal plane
Is set to 50 degrees or more, and the second invention of the present invention is that the inclination angle θ ₁ of the inclined surface of the dust separating cylinder with respect to the horizontal plane is set to about 60 degrees, and the third invention is The dust separating cylinder is arranged so as to be eccentric to one side with respect to the lower smoke exhaust cylinder and the upper smoke exhaust cylinder, and
The invention is characterized in that the dust separation cylinder is arranged so as to be eccentric to one side with respect to the lower smoke exhaust pipe and the upper smoke exhaust pipe, and the exhaust pipe is led out from the side with a large eccentricity. A fifth aspect of the invention is characterized in that the dust separating cylinder is arranged so as to be eccentric to one side with respect to the lower smoke exhaust cylinder and the upper smoke exhaust cylinder, and a dust box is installed below the side where the amount of eccentricity is large.

A sixth aspect of the present invention is that a lower smoke exhaust pipe, a swirl flow generating cylinder continuous with an upper end of the lower smoke exhaust pipe, and an upper exhaust gas disposed above the swirl flow generating cylinder via a predetermined space. A smoke stack, a lower smoke stack including a swirl flow generating cylinder, and an upper smoke stack line were astridely surrounded and enclosed, and a dust discharge port having a reduced diameter was provided at the lower part through an inclined surface. A dust separation cylinder, an exhaust pipe that connects the dust separation cylinder and the upper smoke exhaust pipe, and a dust box detachably attached to the dust discharge port of the dust separation cylinder. A double structure with a cylinder enhances the heat retaining property of the swirl flow generating cylinder portion, and the seventh invention is that the dust separating cylinder and / or the lower smoke exhaust cylinder is covered with a heat insulating material. Is characterized by.

[0015]

According to the above construction, the swirling flow generated by the swirl flow generating cylinder is given to the exhaust smoke rising in the lower smoke exhaust cylinder, and the exhaust smoke containing the soot dust having a large specific gravity swirls along the inner surface of the swirling flow generating cylinder. Come to do. This flue gas is passed through the annular space to the dust separating cylinder,
It is sucked using the negative pressure generated in it. Then, soot and dust in the flue gas having lost the turning force are smoothly accumulated in the dust box along the inclined surface of the dust separating cylinder. Particularly, it is effective when the angle θ _{1 of the} inclined surface is 50 degrees or more with respect to the horizontal plane. On the other hand, the cleaned flue gas is discharged from the dust separating cylinder to the upper flue gas stack through the exhaust pipe.At this time, since a further negative pressure is generated around the annular space, the swirling flow generating cylinder The suction force effectively acts on the smoke exhaust.

Further, since the swirl flow generation cylinder is substantially surrounded by the dust separation cylinder, it is possible to suppress the temperature decrease of the exhaust gas swirling the swirl flow generation cylinder. Therefore, the combustion efficiency in the same portion can be remarkably improved, and a preferable smoke eliminating effect can be obtained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIGS.
Will be described with reference to. In the figure, reference numeral 1 denotes a lower smoke exhaust pipe, a flange 1a for connecting to a smoke exhaust system such as an incinerator or a heat generating engine is provided at a lower end thereof, and a swirling flow producing pipe 2 is provided at an upper end thereof. Are provided integrally with each other. The swirl flow generating cylinder 2 is arranged in the center with an annular space 3 formed by a funnel-shaped enlarged portion 2a continuous with the lower smoke exhaust cylinder 1, an inverted funnel-shaped guide cylinder 2b formed in the upper portion, and a conical upper and lower portion. It is composed of an inner cylinder 4 formed in a shape, and a plurality of inclined guide vanes 5 interposed between the inner cylinder 4 and the swirl flow generation cylinder 2 to impart a swirl flow to the smoke. The upper end portion of the inner cylinder 4 is arranged so as to project from the swirl flow generating cylinder 2. In addition, the inner cylinder 4 may have a hollow inside, or may be empty. An upper smoke exhaust pipe 6 is arranged above the swirl flow generating pipe 2. A flange 6a for connecting to a smoke exhaust system such as an incinerator or a heat generating engine is provided at the upper end of the upper smoke exhaust tube 6, and a cover 7 having a reverse funnel-shaped guide tube is integrally provided at the lower end 6b. Is provided for the purpose. In the cover 7, an annular space 8 is formed between the lower end 6b and the inverted funnel-shaped guide cylinder with respect to the upper smoke exhaust cylinder 6, and an annular space 9 is formed between the cover 7 and the guide cylinder 2b. Are arranged as follows.

Desired portions of the lower smoke exhaust pipe 1, the swirling flow generating pipe 2, and the upper smoke exhaust pipe 6 are substantially surrounded by a dust separating cylinder 10 in a sealed state. The dust separating cylinder 10 is arranged so as to be eccentric to one side with respect to the center of the lower smoke exhaust pipe 1, the swirling flow generating cylinder 2, and the upper smoke exhaust pipe 6, and a portion with a large eccentricity is inclined below the horizontal plane. Angle θ ₁ is 5
A guide cylinder 11 having a small diameter is provided via an inclined surface 10b of 0 ° or more, preferably about 60 °, and a dust discharge port 12 is provided below the guide cylinder 11. The guide cylinder 12 is provided with an inclination angle θ ₂ of about 18 degrees with respect to the vertical plane. Further, a window 13 for inspection is formed in a desired portion of the upper portion of the dust separating cylinder 10 and is always closed by a lid 14.

The upper smoke exhaust cylinder 6 and the dust separating cylinder 10 are connected by an exhaust pipe 16. The inlet 16a below the exhaust pipe 16 is eccentric and has a large area.
The exhaust port 16b penetrates the side surface of the upper smoke flue 6 and faces upward in the central portion. A dust box 17 is hermetically connected to the dust discharge port 12 of the dust separation cylinder 10 by using respective flanges.

Next, the operation of the present invention will be described. First, the flue gas dust remover is installed in a part of the flue gas exhaust system such as an incinerator and a heat generating engine about 1 m above ground. In addition, in the case of being already installed, it is usually installed on the top of a smoke exhaust system (for example, a chimney).
When the smoke containing the sparks, combustion debris, and the like that has risen in the lower smoke exhaust pipe 1 enters the swirl flow generation cylinder 2 through the annular space 3, the swirl flow is imparted by passing through the inclined guide vanes 5. Then, the sparks and combustion debris having a large specific gravity are brought outward by the centrifugal force and ascend while turning along the inner surface of the generating cylinder 2 and reach the guide cylinder 2b. Since the guide tube 2b has an inverted funnel shape and its diameter is reduced as it goes upward, the swirling speed of smoke is accelerated. Therefore, the smoke containing the sparks and combustion debris rising along the inner surfaces of the swirl flow generating cylinder 2 and the guide cylinder 2b is moved outward from the annular gap 9 by the negative pressure and the centrifugal force acting on the annular space 15. It is blown off and drawn into the annular space 15 of the dust separating cylinder 10. And
When the inside of the dust separation cylinder 10 is swirled, and when the swirling force is eventually lost, heavy dust such as sparks and combustion dust naturally falls inside the dust separation cylinder 10, and the dust that falls on the inclined surface 10b is inclined surface 10b. And is accumulated in the dust box 17.

On the other hand, a part of the sparks and combustion debris blown away by the centrifugal force rises as a swirl flow above the swirl flow generation tube 2, but is blocked by the lower end 6b of the upper smoke exhaust tube 6. While turning in the downward annular groove 8 as shown by the arrow in the drawing, the dust is sucked into the dust separating cylinder 10 through the annular space 15 and falls. These soot and dust are collected in the dust box 17.
Accumulated in.

Further, the dust separating cylinder 10 is provided through the annular space 15.
The flue gas drawn into is separated into dust in the separation cylinder 10 and cleaned. The purified smoke is sucked in through the inlet 16a of the exhaust pipe 16 and discharged into the upper smoke exhaust tube 6 through the outlet 16b. In particular, this exhaust pipe 16
Since the exhaust port 16b is provided concentrically with the upper smoke exhaust pipe 6 with its opening facing upward, a central negative pressure acts on the inside thereof due to the exhaust gas flow rising upward around the exhaust gas exhaust port 16b. It will be. Therefore, a larger negative pressure also works in the dust separation cylinder 10 communicating with the exhaust pipe 16, and the annular space 15
Thus, the dust separation cylinder 10 is more effectively sucked with soot and dust such as combustion dust.

According to this apparatus, a swirling flow is generated in the swirling flow generating cylinder by utilizing the upward airflow of the smoke exhaust itself, and soot and dust such as sparks and combustion debris are generated by the centrifugal force in the swirling flow generating cylinder. In order to use the natural law of the airflow, such as guiding the dust to the dust separation cylinder provided around the and separating it, and discharging the purified smoke into the upper smoke stack using the central negative pressure.
No power is required. Therefore, without failure
Maintenance is easy, and the service life is greatly extended.

The inclined surface 10b of the dust separating cylinder 10
Because the inclination angle θ ₁ with respect to the horizontal plane is set to 50 degrees or more, for example, about 60 degrees, even if the dust and soot separated from the smoke is dropped and accumulated on the inclined surface 10b, the slip is smooth and reliable. It will fall. Therefore, soot and the like are efficiently accumulated in the dust box 17.

However, the inclination angle θ ₁ is preferably 50 degrees or more, but if it exceeds 65 degrees, the length of the dust separation cylinder 10 becomes abnormally long and the apparatus becomes large, which is not preferable. On the other hand, if it is less than 50 degrees, soot and the like are extremely difficult to slip off, and the accumulation state in the dust box 17 is deteriorated, so that it cannot be put to practical use. The most preferable inclination angle θ ₁ is about 60 degrees.

Further, the swirling flow generating cylinder 2 is the dust separating cylinder 1.
Because it is covered by 0 and is composed of a double structure,
The temperature of flue gas or the like can be maintained at about 650 ° C., for example. Therefore, the secondary combustion can be effectively performed inside the lower smoke exhaust tube 1 and the swirl flow generating tube 2. Therefore, it is possible to obtain an excellent smoke eliminating effect that the color of the exhaust gas can be made colorless. Incidentally, this smoke eliminating effect cannot be expected at all in a dust collecting device (see Japanese Patent Publication No. 3-17525) in which a swirl flow generating cylinder and a dust separating cylinder, which are proposed by the present applicant, are separately provided. .

In particular, when the invented apparatus is installed on the top of an existing smoke exhaust system (for example, a chimney), even if the dust deposited on the inner surface of the smoke stack is separated and rises due to the rising airflow of the smoke exhaust, A swirling flow is imparted by the swirling flow generating cylinder 2 and is blown into the dust separating cylinder 10 by a centrifugal force and is sucked by negative pressure, so that such dust is not discharged from the chimney to the outside, and It is desirable from the viewpoint of preventing pollution.

The inventors of the present invention installed this device 1 m away from the smoke outlet of the incinerator and examined the dust collecting effect and smoke eliminating effect of soot and dust. We were able to. Further, all the soot dust separated by the dust separating cylinder could be accumulated in the dust box. Furthermore, the temperature of the smoke exhaust in the swirling flow generation cylinder is approximately 650 ° C.
The flue gas emitted from the upper smoke stack was extinguished. Furthermore, when this device was installed on the top of the smoke exhaust port of the boiler, the same effect as that of the incinerator described above was obtained.

The present invention is not limited to the above-described embodiment. For example, one dust box is provided below the dust separating cylinder, and a plurality of dust boxes have an inclination angle of 5 with respect to the horizontal plane.
It can also be provided via a plurality of inclined surfaces of 0 degrees or more.
Further, the inclined guide vanes in the swirl flow generation cylinder are not limited to the form as long as the swirl flow can be generated in the smoke.
Further, a heat insulating material can be attached to the outer surface of the smoke exhaust tube exposed from the dust separation tube.

[0030]

As described above, according to the present invention, the inclined surface of the dust separating cylinder has the inclination angle θ ₁ with respect to the horizontal plane set to 50 degrees or more, so that the dust separated from the smoke exhaust, etc. Will fall down smoothly and surely even if it falls on the slope and accumulates. Therefore, soot and dust are efficiently accumulated in the dust box.

Further, since the exhaust pipe is derived from the portion of the dust separation cylinder having a large eccentricity with respect to the smoke exhaust pipe, the exhaust pipe can be easily arranged and a large negative pressure is generated around the swirl flow generating cylinder. Can be generated. Therefore, the flue gas can be efficiently sucked into the dust separating cylinder.

In particular, since the dust bunker is provided below the portion of the dust separation cylinder having a large eccentricity with respect to the smoke exhaust pipe, soot and the like separated by the dust separation cylinder can be effectively collected.

Furthermore, since the swirl flow generation cylinder is covered with the dust separation cylinder and has a double structure, the temperature of the exhaust gas can be maintained at about 650 ° C., for example. Therefore, secondary combustion can be effectively performed inside the lower smoke exhaust pipe and the swirling flow generation pipe. Therefore, it is possible to obtain an excellent smoke eliminating effect that the color of the exhaust gas can be made colorless.

In particular, when the device of the present invention is installed on the top of an existing smoke exhaust system, a swirling flow is generated even if the soot dust deposited on the inner surface of the chimney separates and rises due to the upward air flow of the smoke exhaust. A swirling flow is imparted by the cylinder, which is blown off into the dust separation cylinder by the centrifugal force and is sucked by the negative pressure, so that such dust is not discharged from the chimney to the outside and the viewpoint of preventing environmental pollution. Is desirable from.

[Brief description of drawings]

FIG. 1 (a) is a side sectional view showing an embodiment of the present invention,
(B) is a plan view of (a).

FIG. 2 is a side view of FIG.

FIG. 3 is a front view of FIG.

FIG. 4 is a side sectional view of a conventional example.

5 is a cross-sectional view taken along the line I-I of FIG.

6 is a sectional view taken along line II-II of FIG.

[Explanation of symbols]

 1 Lower smoke exhaust pipe 2 Swirling flow generating cylinder 2a Enlarged portion 2b Guide cylinder 3,9,15 Annular space 4 Inner cylinder 5 Inclined guide vane 6 Upper smoke exhaust cylinder 6b Lower end 8 Annular groove 10 Dust separation cylinder 10a Upper surface 10b Inclined surface 12 Dust Discharge port 16 Exhaust pipe 16a Inlet port 16b Discharge port 17 Dust box

Claims (7)

[Claims] 1. A lower smoke exhaust pipe, a swirl flow generating cylinder continuous with the upper end of the lower smoke exhaust pipe, an upper smoke exhaust pipe arranged above the swirl flow generating pipe via a predetermined space, and at least a swirl flow generating pipe. A dust separation cylinder that surrounds each of the upper smoke exhaust lines in a sealed manner and that has a dust discharge port that is reduced in diameter through an inclined surface in the lower part; a dust separation cylinder and an upper smoke exhaust pipe; And a dust box detachably attached to the dust outlet of the dust separation cylinder, and the inclination angle θ ₁ of the inclined surface of the dust separation cylinder with respect to the horizontal plane is set to 50 degrees or more. A flue gas dust remover. 2. The flue gas dust remover according to claim 1, wherein an inclination angle θ ₁ of an inclined surface of the dust separating cylinder with respect to a horizontal plane is set to about 60 degrees. 3. The flue gas dust remover according to claim 1, wherein the dust separating cylinder is arranged so as to be eccentric to one side with respect to the lower smoke exhaust cylinder and the upper smoke exhaust cylinder. 4. The dust separating cylinder is arranged so as to be eccentric to one side with respect to the lower smoke exhaust cylinder and the upper smoke exhaust cylinder, and the exhaust pipe is led out from the side with a large eccentricity. Flue gas dust remover. 5. The dust separating cylinder is arranged so as to be eccentric to one side with respect to the lower smoke exhaust cylinder and the upper smoke exhaust cylinder, and a dust box is arranged below a side where the amount of eccentricity is large. The flue gas dust remover described. 6. A lower smoke stack, a swirl flow generating cylinder continuous to the upper end of the lower smoke stack, an upper smoke stack disposed above the swirl flow generating cylinder via a predetermined space, and a swirl flow generating cylinder. A dust separation cylinder that surrounds each of the lower smoke exhaust pipe and the upper smoke exhaust pipe in a hermetically-sealed manner, and that has a dust discharge port that is reduced in diameter through an inclined surface in the lower portion, and a dust separation cylinder. An exhaust pipe communicating with the upper smoke exhaust pipe and a dust box detachably attached to the dust discharge port of the dust separation cylinder are provided, and the swirl flow generating cylinder portion has a double structure with the dust separation cylinder. The flue gas dust removing device is characterized in that the heat retaining property of the swirling flow generating cylinder portion is enhanced by the above. 7. The flue gas dust remover according to claim 6, wherein the dust separating cylinder and / or the lower smoke exhaust cylinder is covered with a heat insulating material.