JP2595193B2 - Mist removal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mist removal device for separating and removing mist mixed with soot and dust in exhaust gas discharged from a gas cleaning device at a preceding stage to protect a suction blower at a later stage.

[0002]

2. Description of the Related Art Exhaust gas discharged from a combustion furnace such as a boiler or a refuse incinerator contains soot and dust, and a gas cleaning device is generally provided in the discharge system to remove these from the exhaust gas. After being washed with a washing liquid or water and passing through a filter, the air is attracted by a suction blower and discharged to the outside.

[0003] In the cleaning by a gas cleaning apparatus, it is a general method to contact exhaust gas with a grid-shaped filter provided in a direction orthogonal to the exhaust flow to remove mist, soot and dust of the cleaning liquid in the exhaust gas. However, it is impossible to completely remove mist, dust, and the like, and extremely fine particles are discharged as mist by being included in droplets or the like due to splashes during washing.

As means for temporarily separating and removing soot and dust in exhaust gas, there is known, for example, Japanese Utility Model Publication No. Sho 42-16235 other than the gas cleaning apparatus.

The soot treatment device according to this publication is used by being inserted in the middle of a chimney, and the upper end of a connecting pipe having the same diameter as the lower chimney is throttled to generate a swirling flow in a blade chamber for receiving a gas flow having an increased flow velocity. By applying force, a swirl flow is generated in the funnel-shaped swirl chamber, cuts are provided in the outer peripheral wall, dust and the like are primarily separated and removed from a through hole formed by obliquely pushing the tongue piece into the inner peripheral wall, It is formed to send a thin gas stream of dust on the center side to the upper chimney.

[0006]

However, it is important to primarily remove soot and dust in the above-mentioned exhaust gas, that is, to separate and remove coarse powder and particulate matter, in the case of exhaust gas treatment. In this case, it is impossible to completely separate and remove ultrafine dust and dust.

[0007] In particular, in the case of a gas cleaning device, dust droplets
Ultrafine mist containing dust remains, and if the mist is discharged as it is, it adheres to the impeller or the like of the blower, causing imbalance and corroding the impeller or the like, which may cause an accident.

[0008] In addition, the performance may be adversely affected, and it may be difficult to operate the induction blower normally for a long period of time. Therefore, it is necessary to further secondary-separate and remove ultra-fine mist including dust and dust. is there.

Therefore, as a secondary separation / removal means to meet the above-mentioned object, a mist removal apparatus disclosed in Japanese Patent Application Laid-Open No. 62-13819 has already been proposed. This mist removing device has a cylindrical main body equipped with a drum having a small-diameter discharge cylindrical part in the upper part and a guide blade provided in the center part on the lower gas inflow side, and an outer periphery of the main body, And a collecting pipe communicating with the inside of the main body through the window hole provided in the main body.

The mist removing device according to the above-mentioned application eliminates any projection inside a window hole for communicating with a collecting pipe around the outside of the main body, and a centrifugal gas generated in an exhaust gas flow by a drum having guide vanes. It has an excellent effect in that the mist is separated by force and turbulence is not generated in the vicinity of the window hole so that the action of separating and removing the mist can be reliably obtained.

However, in the above mist removing device,
A drum having guide vanes for imparting a centrifugal separation effect to the exhaust gas flow has a limit in increasing the separation effect by centrifugal force because the guide vanes are provided on a surface parallel to the main body inner diameter.

Further, since exhaust gas orbiting behind the drum is collected at the center side and discharged from the discharge pipe, if a turbulence occurs in the swirling flow due to a slight fluctuation factor inside the main body, the center side is exhausted. There is a problem that the mist separation efficiency is reduced due to mixing of the mist with the outside exhaust gas.

The present invention has been made in consideration of the above-mentioned problems of the conventional mist removing device, and has an object to obtain a mist removing device having a simple structure and economical cost and capable of performing a separating / removing action by a large centrifugal force. Make it an issue.

[0014]

As a means for solving the above problems, the present invention comprises an outer cylinder and an inner cylinder provided concentrically inside the outer cylinder, one end of the outer cylinder being an opening through which exhaust gas flows,
Cones having guide vanes at appropriate intervals along the conical surface facing the inlet opening are provided at the end of the inner cylinder, and mist is separated from exhaust gas flowing while turning the space between both cylinders downstream of the cone with the guide vanes. A slit for discharging mist is formed on the outer cylinder wall corresponding to this separation area.
Vertically and obliquely to the flow of exhaust gas and substantially parallel to each other
The mist removing device is provided in a stepped manner, the lower end of the space is closed, an opening for receiving exhaust gas from which mist has been removed is provided in the inner cylinder wall, and the downstream end of the inner cylinder is used as an exhaust gas outlet.

[0015] As this preferred embodiment, it can be those larger than the inner cylinder diameter base diameter before Kien cone.

[0016] In yet another embodiment, prior to SL and the communicating slit of each slit narrow curved, outside air of the collecting pipe provided with a collecting tube for collecting the mist that is discharged from the slit in the outer tube outwardly It is preferable to provide a discharge section for interrupting communication to remove mist.

[0017]

The mist removing device according to the first aspect of the present invention is configured so that exhaust gas is sucked by an induction blower provided at the rear of the device and is used so as to flow through an inlet opening. The exhaust gas is discharged from a combustion furnace such as a boiler, and the exhaust gas contains soot and dust.

Exhaust gas flowing from the inlet opening is sent in the circumferential direction by guide vanes provided on the surface of the cone and, while rotating, flows between the inner wall of the outer cylinder and the base of the cone into the separation region. While further turning in this separation region, the heavy liquid mist containing soot and dust contained in the exhaust gas reaches the inner wall of the outer cylinder by centrifugal force and is discharged to the outside through a slit provided in the outer cylinder.

When the mist is centrifuged, the mist of the exhaust gas is centrifuged in a separation region consisting of a narrow donut-shaped space between the inner cylinder and the outer cylinder. Therefore,
Even the mist in the exhaust gas diffused to the inner cylinder side easily reaches the outer cylinder inner wall because the flight distance to the outer cylinder inner wall is short.

The mist thus separated and removed is discharged to the outside through the slit, and the exhaust gas from which the mist is separated and removed is discharged as a clean gas from an outlet below the inner cylinder.

[0021] In apparatus of the second invention, has been larger than the inner cylinder diameter circular cone base diameter, in this case, exhaust gas flowing from the inlet opening flows from cone base and a large pivotal movement to the separation region . For this reason, the centrifugal separation action is large, and the mist collection efficiency is maximized.

In the third aspect of the invention, the slit is formed as a multi-step finely curved communication slit, and a mist collection pipe for discharging the slit is provided outside the outer cylinder, and the discharge section of the collection pipe communicates with the outside air. I try to cut off.

For this reason, outside air does not flow into the separation area through the slit, and turbulence is prevented from being generated in the separation area, and the separation / removal action by the centrifugal force is larger than the suction force. The mist is efficiently separated / removed and collected without being sucked toward the inner cylinder by the suction force.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a mist removing device according to an embodiment, and FIG. 2 is a main sectional view thereof.

A concentric inner cylinder is provided inside the outer cylinder 1. One end of the outer cylinder 1 has a reduced diameter and an inlet pipe 3 is connected thereto. The inlet pipe 3 is an exhaust pipe through which exhaust gas in which ultrafine particulate dust and mist containing dust are mixed into droplets after dust and dust having a large particle diameter are removed by a gas cleaning device (not shown) upstream. (Not shown), which is generally the same diameter as the exhaust pipe.

At a position slightly inside the outer tube 1 from the inlet tube 3, a conical drum 4 provided with the conical surface facing the inlet tube 3 is fixed to the same side end of the inner tube 2. The upper end of the cylinder 2 is sealed. As shown in the drawing, the conical drum 4 has a cross section just like an abacus ball, and the diameter of the conical drum base (the portion having the largest diameter) is larger than the diameter of the inner cylinder 2. On the conical surface of the conical drum 4, as shown in the cross section of FIG. 3, guide blades 5 are provided upright at appropriate intervals along the conical surface so as to form a substantially spiral part.

The space between the outer cylinders on the downstream side of the conical drum 4 is designated by A as a separation region, where mist in the exhaust gas is separated and removed. Inner cylinder openings 6 for receiving exhaust gas are provided at predetermined intervals on the inner cylinder wall of the separation area, and slits 7 are also provided at predetermined intervals on the outer cylinder wall.

A collecting pipe 8 is provided outside the outer cylinder wall where the slit 7 is provided, and a collecting connecting pipe 8a for collecting mist from the collecting pipe 8 at an appropriate position below the slit 7. Is provided on the outer periphery of the outer cylinder, and S
A drain pipe 9 including a character trap 9a is connected.

In the separation area A, the lower part of the space between the outer cylinders is closed by a blind plate 1a. Also, inner cylinder 2
The downstream side is opened as an inner cylinder discharge part 10 and is formed so as to be connectable to a downstream exhaust pipe (not shown). A plurality of drain holes 11 are provided at appropriate positions, and the drain holes collect in a portion closed by the blind plate 1a.

[0030] FIG. 4 shows a partially enlarged view of the slit 7 as viewed from an arrow IV-IV of FIG. As shown in the drawing, the slit 7 is formed by connecting the communication slit 7 having a fine curved shape in a multi-stage manner in the upper and lower directions and the outer cylinder 1.
It is provided obliquely in a direction substantially along the flow of the exhaust gas that swirls along the inner peripheral wall of the airbag. Communication slit 7a
For example, in this embodiment, the width is 5 mm, the radius of curvature is 70 mm,
The length of the arc is a fine curve of about 40 °. This is only an example, and the present invention is not limited to this.

In the mist removing device of the embodiment having the above-described structure, mist is removed as follows.

When the exhaust gas containing mist containing fine particulates and dust sent from the upstream gas cleaning device flows vertically from the inlet pipe 3, the conical drum 4 spreads outward from the center of the circle outward. Is guided by the guide vanes 5 and moves in a circular motion to the separation area A downstream of the conical drum 4 and flows spirally in the separation area A.

When the guide blade 5 of the conical drum 4 makes a circular motion, the diameter of the base (the largest part of the diameter) of the conical drum 4 is larger than the diameter of the inner cylinder 2. Since the exhaust gas passes through the gap between the base portion and the inner wall of the outer cylinder 1 while passing through the outer cylinder 1 while being spirally moved, the inertia force and the centrifugal force in the outer direction are simultaneously applied to most of the exhaust gas. Works.

The exhaust gas which has received the above inertial force and centrifugal force travels in a state where the centrifugal force continues to act while spirally moving even after passing through the gap, so that the mist having a large specific gravity mostly travels along the inner wall of the outer cylinder. . On the other hand, the exhaust gas that has passed through the gap has a smaller passage diameter because the diameter of the inner cylinder 2 is smaller on the downstream side than the base of the conical drum 4, so that a part of the exhaust gas diffuses inward.

However, even if the exhaust gas partially diffuses inward, the mist still having a large specific gravity continues to move to the outside of the space, that is, to the inner wall of the outer cylinder 1 even in the separation region A because the swirl flow still remains as a whole. It is done. In this case, the flight distance from the base of the conical drum 4 to the inner wall of the outer cylinder 1 is extremely small, and even if a part of the exhaust gas diffuses inward, the outer cylinder 1
The mist can easily reach the inner wall of the outer cylinder 1 because the flight distance to the inner wall is not so large.

By the way, in a conventional soot treatment device or the like for performing primary separation, the inner cylinder 2 is placed in the separation region A as in this embodiment.
Is not provided, and immediately after passing through the portion corresponding to the conical drum 4 and the guide blade 5 of this embodiment, the exhaust gas that goes straight and a part thereof moves in a circular motion, and the dust and the dust are separated by centrifugal separation. Is mixed again in the downstream region, so that even if the mist moved to the center side and having a large specific gravity is swirled, the distance to the outer peripheral wall is too large to reach the outer peripheral wall.

As described above, most of the mist separated and removed from the exhaust gas reaches the inner peripheral wall of the outer cylinder 1 while the exhaust gas flow is swirling and descends the separation area A. Are provided with slits 7 at appropriate intervals, and the mist is discharged outside the outer cylinder 1 through the slits 7.

The slit 7 is provided with a communication slit 7a formed in a fine curve along the swirl flow of the exhaust gas in a multi-tiered manner. This is because if a wide slit is provided on the inner peripheral surface of the outer cylinder 1, there is a possibility that turbulent flow may occur in the exhaust gas flow including the mist that has reached the inner peripheral wall, and this is prevented.

The communication slit 7a is originally desirably a point-like small hole, but it is not realistic to provide many continuous slits. For this reason, the slit 7 of this embodiment has a number of small holes communicating with each other to form a fine curve.

The mist discharged from the slit 7 is
While contacting and coarsening with each other, they are collected by the collection communication pipe 8a through the collection pipe 8 and discharged from the drain pipe 9 to reach, for example, an external storage tank (not shown). At this time, an S-shaped trap 9a is provided in the middle of the drain tube 9, and the inside of the collection tube 8 is shut off from the outside air by the liquid part sealed therein.

For this reason, the inner cylinder discharge portion 10 below the inner cylinder 2
Even if a suction force is applied from an induction blower connected to the rear of the exhaust pipe, the suction force does not directly suck the outside air from the drain pipe 9 to prevent the exhaust gas flow from becoming turbulent.
Even if the above-mentioned suction force acts, the mist separated and removed in the separation area A is extruded in the radial direction by the swirling speed and the centrifugal force so that the action is more than the suction force. The removal action is not inhibited.

Accordingly, it is desirable that the slit 7 be a communication hole which can maintain the cross-linking of the fluid in the exhaust gas flow in view of the relationship between the swirling speed and the centrifugal force, that is, can maintain the flow so as not to hinder the continuous flow. For this reason, the slit 7 is a thin curved communication slit, and as shown in FIG. 4, the slit 7 is arranged so as to cover the width of the exhaust gas in the direction of the exhaust gas flow.

Near the inner peripheral wall surface of the outer cylinder 1 provided with the slit 7, there is a possibility that a slight turbulence may occur in the swirl flow due to the provision of the slit 7, but the exhaust gas flow swirls immediately after passing through the slit surface. The flow can be prevented from being restored by centrifugal force and leaving the fluid turbulent. That is, as shown in FIGS. 4 and 5, the fluid pressure (surface pressure) of the swirling flow at the slit 7 causes a drop and undulation at a width and a length which are not applied to a very large area, thereby reducing the influence of the turbulent flow. Prevent it. More specifically, as shown in FIG. 4, the drop and the undulation are sequentially performed to the right at a predetermined width (the width of the slit 7). In other words, the fluid located at a vertical angle in the flow direction falls and undulates in a small area with a time difference. This minimizes turbulence. If the slits 7 are provided in multiple stages, the entire height (separation region) can be covered.

Furthermore, even if powder (solid state) is mixed in the mist of the exhaust gas flow, the surface of the communicating slit is constantly washed by the liquid mist, so that the slit is not clogged and continuous for a long time. There is no fluctuation in the collection efficiency and pressure loss even when the operation is performed.

The exhaust gas from which the mist has been almost completely separated and removed is sucked by the induction blower and discharged from the inner cylinder discharge section 10. Since the exhaust gas is in a clean state, the induction blower and the like need not be contaminated. Becomes

In the above embodiment, the inlet pipe 3 serving as the exhaust gas inlet opening of the outer cylinder 1 is slightly smaller than the inner cylinder diameter. However, the inlet opening is not necessarily smaller than the inner cylinder diameter. For example, it may be the same as the maximum diameter portion of the outer cylinder 1, or may be an arbitrary diameter in the middle.

In such a case, as in the above embodiment, the inlet pipe 3
Although the centrifugal force when the swiveling motion is given by the guide blade 5 slightly decreases, the maximum centrifugal force can be obtained by adjusting the suction force, the angle of the guide blade, the diameter of the conical drum, the conical ratio, and the like. What should I do?

[0048]

As described in detail above, the mist removing device of the first invention of this application has a conical drum having guide vanes at the end of an inner cylinder provided in an outer cylinder, and has an inlet opening at the end of the outer cylinder. The mist is separated and removed from the exhaust gas by the centrifugal action of the exhaust gas flowing in from the cylinder to discharge clean exhaust gas, so it can be manufactured with a simple configuration at economical cost and inserted into the exhaust pipe. Since it is free, installation is easy, and there is an advantage that a mist removing device with extremely high collection efficiency for separating and removing mist can be obtained.

[0049] In the second invention, distance of from were larger than the inner cylinder diameter circular cone base diameter, large centrifugal force to the exhaust gas acts, from a position separated off mist by centrifugal force to the outer tube inner wall And the mist is separated and removed with extremely high collection efficiency.

In the third invention, the slit is formed as a multi-stage communication slit, and communication with the outside air is interrupted by a discharge portion provided in a collection tube for collecting the mist discharged from the slit. Accordingly, an advantage is obtained that the exhaust gas is sucked without the separation region communicating with the outside air, so that the mist separation / removal operation can be surely obtained without generating a turbulent flow in the separation region in the outer cylinder.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a mist removing device according to an embodiment.

FIG. 2 is a main sectional view of the above.

FIG. 3 is a sectional view taken along arrow III-III in FIG. 2;

FIG. 4 is an enlarged view as viewed from arrows IV-IV in FIG. 2;

FIG. 5 is an explanatory diagram of an operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Inner cylinder 3 Inlet pipe 4 Conical drum 5 Guide vane 6 Inner cylinder opening 7 Slit 8 Collection pipe 9 Drain pipe 10 Inner cylinder discharge part

Claims (3)

(57) [Claims] 1. An outer cylinder and an inner cylinder provided concentrically inside the outer cylinder. One end of the outer cylinder is an opening through which exhaust gas flows, and guide blades are provided at appropriate intervals along a conical surface facing the inlet opening. A conical body is provided at the end of the inner cylinder, and a space between the two cylinders downstream of the conical body is used as a separation area for separating mist from exhaust gas flowing while rotating with the guide vanes, and mist is formed on the outer cylinder wall corresponding to the separation area. Discharge slit for discharging
Up and down multi-stage with slanted shape and almost parallel to each other
A mist removing device, wherein the lower end of the space is closed, the inner cylinder wall is provided with an opening for receiving the exhaust gas from which the mist has been removed, and the downstream end of the inner cylinder is used as the exhaust gas discharge port. 2. A mist removing apparatus according to claim 1, characterized in that a larger than the inner cylinder diameter base diameter before Kien cone. 3. Before SL slits and thin curved communicating slits, cuts off the communication between the outside air collecting tube for collecting the mist that is discharged from the slits to the collecting tube with an outer tube provided on the outer The mist removing device according to claim 1 or 2, wherein a mist is removed by providing a discharge unit.