JPH0683768B2 - Dust remover - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dust remover having a filter cylinder made of breathable porous ceramics, and more particularly to a dust remover having a backwash gas discharge port.

"Prior art and its problems" Filter dust removers using filter cloth as a filter medium have been widely used, but in such dust removers, the temperature of dust-containing gas is low because the filter cloth has poor heat resistance. Above 250 ° C it can no longer be used.

Therefore, the present applicant has proposed, as a dust removing device that can be used for high-temperature dust-containing gas, a device using a breathable porous ceramics body or the like as a filter medium (see Japanese Patent Laid-Open No. 59-225721). In this dust remover, the dust-containing gas is supplied from above into the filter cylinder made of the air-permeable porous ceramic that is installed upright, and the clean gas flows out from the inside of the filter cylinder to the outside,
Part of the dust blocked by the filter cylinder is deposited on the inner wall of the filter cylinder, and most of the dust falls inside the filter cylinder and is collected in a dust hopper provided below the filter cylinder.

By the way, in such a filter and dust remover, when the dust removing operation is continuously performed, the filter medium gradually becomes clogged, the differential pressure required for filtration increases, and the filtration speed decreases. Therefore, it is necessary to perform a so-called backwashing operation in which a dust is clogged by flowing gas from the clean gas side to the dust-containing gas side every dust removal operation for a predetermined time.

In a dust remover that uses a filter cloth, a high-pressure gas jet nozzle is installed in the clean gas outlet pipe during dust removal operation with its opening facing the filter cloth, and a high-speed gas is jetted from here during the backwash operation. Washing methods are well known. According to this method, when ejected toward the filter cloth, the filter cloth vibrates and flutters, and the dust accumulated inside the filter cloth is removed.

However, if the backwashing method used for removing dust on the filter cloth is directly applied to a dust removing device using a breathable porous ceramics (hereinafter referred to as a solid filter) as a filter medium, the following problems occur. First, if the temperature of the treated gas is high, direct spraying a backwash gas at about room temperature will cause the solid filter to
Since it is made of ceramics, it is vulnerable to thermal shock, and a rapid temperature difference locally occurs, resulting in thermal shock damage. Also,
When the backwash gas is made to flow through the clean gas outlet duct, the high temperature clean gas and the low temperature backwash gas are not mixed well and hit the solid filter without the temperature being homogenized. Temperature difference occurs, and thermal shock damage is more likely to occur. Further, when the backwash gas is sprayed onto the solid filter at a high speed, damage due to mechanical shock may occur.

"Object of the Invention" An object of the present invention is to reduce the thermal shock caused by locally abrupt temperature difference in the solid filter during backwashing when there is a temperature difference between the treatment gas temperature and the backwashing gas temperature. (EN) It is possible to provide a dust removing device which prevents damage due to mechanical shock and also prevents mechanical damage caused by backwash gas on a solid filter and prevents damage due to mechanical shock.

"Structure of the invention" The dust remover according to the present invention is a dust remover which supplies a dust-containing gas to the inside of a filter cylinder made of porous ceramics having air permeability and takes out clean gas from the outside of the filter cylinder. The backwash gas discharge port is provided in the space on the side so that the discharge direction of the backwash gas and the axial direction of the filter cylinder are substantially parallel to each other, or are not substantially on the same plane. The backwash gas discharge port is arranged.

Thus, in the present invention, since the backwash gas discharge port is arranged so that the backwash gas does not directly hit the filter cylinder, the backwash gas is mixed with the hot clean gas through a relatively long path,
It will hit the filter tube. For this reason, since the backwash gas is heated and hits the solid filter, a sudden temperature difference is not locally generated in the solid filter, and damage due to thermal shock is prevented. In addition, the backwash gas can be mixed with the clean gas before the solid filter hits to reduce the flow rate,
The mechanical shock applied to the solid filter is also mitigated, and damage due to the mechanical shock is prevented.

In a preferred aspect of the present invention, the backwash gas discharge port is arranged so that the discharge direction of the backwash gas and the axial direction of the filter cylinder are substantially parallel to each other. As a result, when backwashing using an ejector or the like, the diffuser portion can be housed in the can body, and the installation area of this dust removing device including the backwashing device can be saved.

In another preferred aspect of the present invention, the clean gas side space is divided into a plurality of small spaces by a tube plate through which the filter cylinder is inserted, and the backwash gas discharge port is arranged in each small space. Thereby, the backwash operation can be carried out without stopping the dust removal operation.

In another preferred embodiment of the present invention, the backwash gas discharge port is arranged so that the direction of discharge of the backwash gas is along the inner peripheral wall of the can body housing the filter cylinder. Thus, the backwash diffuser portion can be installed at a position along the can body, a large number of filter cylinders can be accommodated in the can body, and the installation area of this dust removing device including the backwash device can be reduced.

As the material of the solid filter, a ceramic material is used because it has excellent heat resistance and corrosion resistance. further,
Considering that rapid temperature change at the start and stop of operation or temperature change of dust-containing gas itself is not rare when removing dust of high-temperature dust-containing gas by taking advantage of heat resistance, it has excellent thermal shock resistance. Ceramics are particularly preferable. Specific examples include those made of ceramics such as cordierite, β-spodumene, zirconia, and aluminum titanate.

The filter cylinder has a hollow cylinder shape, particularly a hollow cylinder shape, and a dust-containing gas is supplied to the space inside thereof. As a result, the space on the clean gas side communicates and surrounds the outside of the filter cylinder, and even if one or several backwash gas discharge ports are localized at specific positions in the clean gas side space, The backwash gas can flow into the entire side space. Further, the hollow cylindrical shape minimizes the risk that the filter cylinder is damaged due to the pressure difference between the inside and outside of the filter cylinder. Further, the filter cylinder may be arranged in the horizontal direction or the inclined direction, but is preferably arranged in the vertical direction. As a result, it is possible to prevent the dust particles that have been separated by filtration from falling one after another and reducing the dust removal efficiency.

The backwash gas discharge port may be attached to an independent introduction pipe introduced into the space on the clean gas side, but is preferably provided in the clean gas outlet duct. In this way, by using the backwash gas discharge port and the clean gas outlet duct as well, it is possible to reduce the number of openings provided in the can body.

In providing the backwash gas discharge port in the clean gas outlet duct, a double pipe type and a branch pipe type can be preferably proposed.

The double-tube type is a system in which a smaller-diameter backwash gas inlet pipe is coaxially installed inside the clean gas outlet duct, and the airflow, especially the high-speed airflow such as the pulse jet method, is blown out from the backwash gas inlet pipe. As a result, the clean gas existing in the vicinity is additionally taken in by the ejector effect, and a much larger amount of gas than the blown out gas can be used as the backwash gas.

The branch pipe type is one in which a branch pipe that opens to the wall of the clean gas outlet duct is provided, and preferably a valve is provided in each of the clean gas outlet duct and the branch pipe downstream of this opening, and according to this, a double pipe type The required amount of backwash gas can be reliably and easily obtained by blowing out a high-speed airflow to a certain degree even if the backwash gas is not as fast as in the above case.

"Embodiment of the Invention" In Fig. 2 and Fig. 1 which shows a cross section taken substantially along the line I-I in Fig. 2, a plurality of hollow cylindrical filter cylinders 11 are cylindrical at appropriate intervals. It is housed in a can body 12. The filter cylinder 11 is made of a breathable porous solid made of a cordierite, particularly β-cordrite, ceramic sintered body.

Head 14 with dust-containing gas inlet 13 and dust cut-out valve
Hoppers 16 with 15 are attached above and below the can 12, respectively. Multiple (4 in Fig. 1) tube sheets
17 is provided inside the tubular body 12 to hold the filter cylinder 11.
The tube sheet 17 is kept airtight with the filter tube 11 and the can body 12, respectively, and a clean gas chamber is provided between adjacent tube sheets 17.
Forming eighteen. The upper end and the lower end of the filter cylinder 11 are open to the header 14 and the hopper 16, respectively. At least two tube plates 17 may be provided, and the intermediate tube plate may be one that allows the upper and lower clean gas chambers 18 to communicate with each other.

In each of the clean gas chambers 18, clean gas outlet ducts 21, 22, 23 are introduced from the header 14 side through the required tube sheet 17 in an airtight manner. The clean gas outlet ducts 21, 22, 23 are arranged in parallel with the filter cylinder 11, and the diffusers 24, 2 are respectively provided at the tips.
5, 26 are installed and each diffuser 24, 25, 26
Open to the respective clean gas chambers 18. In addition, backwash gas introduction pipes 27, 28, 29 are coaxially arranged in the clean gas outlet ducts 21, 22, 23, respectively. The tips of the backwash gas introduction pipes 27, 28, 29 are respectively reduced in diameter to form backwash gas discharge ports 30, 31, 32, which are located in front of the reduced diameter portions of the diffusers 24, 25, 26, respectively. . The first
In the figure, illustration of the filter cylinder 11 located behind is omitted.

This dust remover operates as follows. First, at the time of a dust removing operation, a high temperature dust-containing gas is introduced from the dust-containing gas introduction port 13 and distributed to flow down inside each filter cylinder 11. Along with the flow down, the dust-containing gas is filtered out by the filter cylinder 11, part of the dust accumulates on the inner wall of the filter cylinder 11, and most of the dust falls downward and collects in the hopper 16. The hot clean gas passes through the filter wall of the filter cylinder 11 and enters each clean gas chamber 18, and passes through the diffusers 24, 25, 26 and the clean gas outlet ducts 21, 22, 23 opened in each clean gas chamber 18. Are out of the system. During this time, the filter cylinder 11 is gradually clogged with dust and the filtration resistance increases. Therefore, the backwash operation is performed after the predetermined dust removal operation.

At the time of the backwashing operation, a compressor or the like (not shown) is operated, and high-speed backwashing gas is ejected from the backwashing gas discharge ports 30, 31, 32 through the backwashing gas introduction pipes 27, 28, 29. The backwash gas also takes in clean gas existing in the periphery due to the ejector effect in the reduced diameter portion of the diffusers 24, 25, 26, and is a gas several times as much as the gas ejected from the backwash gas discharge ports 30, 31, 32. The amount becomes the amount and is discharged into each clean gas chamber 18 through the openings of the diffusers 24, 25 and 26.

In this case, since the backwash gas is discharged downward in parallel with the filter cylinder 11, the backwash gas hits the filter cylinder 11 after being bent or circulated in the clean gas chamber 18. Therefore, the backwash gas hits the filter cylinder 11 after being mixed with a high temperature clean gas and heated, so that a sharp temperature difference does not locally occur in the filter cylinder 11 and damage due to thermal shock is prevented. It Further, since the backwash gas is mixed with the clean gas until it hits the filter cylinder 11 and the flow velocity thereof is weakened, the mechanical shock given to the filter cylinder 11 is alleviated and the damage due to the mechanical shock is prevented. Thus
The backwash gas passes through the wall of the filter cylinder 11 from the outside to the inside, whereby the dust causing the clogging is washed out, and the filter cylinder
The gas passage resistance of 11 is reduced and the filter cylinder 11 is regenerated.

The dust removing operation and the backwashing operation are alternately performed on the same portion of the filter cylinder 11, but as shown in FIG.
, If they belong to a plurality of clean gas chambers 18 that are airtight to each other, by performing a backwash operation alternately in each clean gas chamber 18, the dust removing apparatus as a whole does not interrupt the dust removing operation, and It is also possible to perform a washing operation. For example, if a backwash operation is performed in the upper clean gas chamber 18, the backwash gas enters the inside of the filter cylinder 11 from the upper clean gas chamber 18 to regenerate the filter cylinder of this portion, and the backwash gas that has entered. The gas passes through the filter tube 11 in the middle or lower stage and goes out to the clean gas chamber 18 in the middle or lower stage. If such operations are sequentially performed in the clean gas chambers 18 in the upper, middle and lower stages, the backwash operation can be performed without interrupting the dust removing operation as the entire dust removing apparatus.

In the above embodiment, the backwash gas introduction pipes 27, 28,
29 and the backwash gas discharge ports 30, 31, 32 are arranged in parallel with the filter cylinder 11 so that the backwash gas is discharged in a direction parallel to the filter cylinder 11, which is preferable, but as shown in FIG. In addition, the angle θ formed by the discharge direction A of the backwash gas and the axial direction of the filter cylinder 11 is 10 °.
The effects of the present invention can be obtained in the following cases. In this case, the discharge direction A of the backwash gas may be toward or away from the filter cylinder 11, and the backwash gas introduction pipe and the clean gas discharge duct do not pass through the tube sheet 11 and the can body 12 It may be introduced into the clean gas chamber 18 directly from the side body.

In another embodiment shown in FIG. 4, a diffuser 34 attached to the tip of the clean gas lead-out duct 33 has its expanded portion directly connected to the can body 12. In the case of this embodiment, the clean gas lead-out ducts 33 are provided at two locations on the outer periphery of the can body 12 which face each other. A backwash gas introduction pipe 35 is arranged in each clean gas outlet duct 33, and a backwash gas discharge port 36 at the tip thereof is positioned in front of the reduced diameter portion of the diffuser 34. In the case of this embodiment, the clean gas outlet duct
33, the diffuser 34, the backwash gas introduction pipe 35, and the backwash gas discharge port 36 are arranged so that the direction of discharge of the backwash gas is along the inner peripheral wall of the can body 12. The supporting structure of the filter cylinder 11 and the dust-containing gas introducing structure are the same as those in the embodiment of FIG.

In this embodiment, the backwash gas is discharged along the inner peripheral wall of the can body 12, circulates in the can body 12, and then contacts the filter cylinder 11. Therefore, the backwash gas comes into contact with the filter cylinder 11 after being mixed with the clean gas in the can body 12 and heated, and a sharp temperature difference does not locally occur in the filter cylinder 11. , Damage due to thermal shock is prevented. Further, since the backwash gas is mixed with the clean gas until it hits the filter cylinder 11 and the flow velocity thereof is weakened, the mechanical shock given to the filter cylinder 11 is alleviated and the damage due to the mechanical shock is prevented.

In the above embodiment, the clean gas outlet duct 33, the diffuser 34, the backwash gas introduction pipe 35 and the backwash gas discharge port 36.
Are arranged along a plane perpendicular to the axial direction of the filter cylinder 11, but may be obliquely arranged at an angle to the plane perpendicular to the axial direction of the filter cylinder 11. In that case, the backwash gas will flow out in a spiral shape along the inner peripheral wall of the can body 12. Further, in the above embodiment, the two backwash gas discharge ports 36 are on the same vertical plane with respect to the axial direction of the filter cylinder 11, but instead of this, a plurality of backwash gas discharge ports 36 are used.
It may also be provided on different cross-sections across 11.

In each of the above embodiments, the backwash gas introduction pipe is arranged in the clean gas lead-out duct, but the clean gas lead-out duct and the backwash gas lead-in pipe may be individually connected to the can body. . Further, it is desirable that the backwash gas discharge port 36 is provided inside the can, or is provided near the can even outside the can.

The embodiment shown in FIG. 4 is a case of the backwash gas discharge method as shown by the arrow B in FIG. 5 and is preferable, but the backwash gas discharge direction as shown by the arrow C is shown. Can also obtain the effect of the present invention. The backwash gas discharge direction as shown by the arrow D is not preferable.

[Advantages of the Invention] As described above, according to the present invention, the backwash gas discharge port is arranged so that the backwash gas does not substantially directly contact the filter cylinder. After passing through and mixing with the hot clean gas, it comes into contact with the filter tube. Therefore, the backwash gas is heated and hits the solid filter,
No sudden temperature difference locally occurs in the solid filter, and damage due to thermal shock is prevented. Further, since the backwash gas is mixed with the clean gas to weaken the flow velocity thereof before hitting the solid filter, the mechanical shock given to the solid filter is mitigated and the damage due to the mechanical shock is prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a dust remover according to an embodiment of the present invention with a part cut away, FIG. 2 is a transverse sectional view taken along line II-II in FIG. 1, and FIG. 3 is an implementation of FIG. FIG. 4 is an explanatory view schematically showing a modified example of the example, FIG. 4 is a cross-sectional view of a dust remover according to another embodiment of the present invention, and FIG. 5 is an explanatory view schematically showing a modified example of the embodiment of FIG. It is a figure. In the figure, 11 is a filter cylinder, 12 is a can, 13 is a dust-containing gas inlet, 14 is a header, 15 is a cutoff valve, 16 is a hopper, 17 is a tube plate, 18 is a clean gas chamber, 21, 22, 23, 33 is a clean gas outlet duct, 24, 2
5, 26 and 34 are diffusers, 27, 28, 29 and 35 are backwash gas introduction pipes, and 30, 31, 32 and 36 are backwash gas discharge ports.

Claims (4)

[Claims] 1. A dust remover for supplying a dust-containing gas to the inside of a filter cylinder made of a porous ceramic having air permeability and taking out a clean gas from the outside of the filter cylinder. The backwash gas discharge port is provided with a discharge port so that the discharge direction of the backwash gas and the axial direction of the filter cylinder are substantially parallel to each other or not substantially on the same plane. A dust removing device characterized in that 2. The backwash gas discharge port according to claim 1, wherein the backwash gas discharge port is arranged such that a discharge direction of the backwash gas and an axial direction of the filter cylinder are substantially parallel to each other. And dust remover. 3. The clean gas side space is divided into a plurality of small spaces by a tube plate through which the filter cylinder is inserted, and the backwash gas discharge port is provided in each small space. A dust remover characterized by being placed. 4. The backwash gas discharge port according to claim 1 or 3, wherein the backwash gas discharge direction is along the inner peripheral wall of the can body accommodating the filter cylinder. A dust removing device characterized in that