JP2009113015A - Bag filter structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide bag filter structure having a filter cloth structure providing preferable soot and dust shaking-off performance by increasing an amount of deformation of the filter cloth. <P>SOLUTION: In the bag filter structure provided with a pulse jet backwashing type filter cloth structure 20 wherein soot and dust in combustion flue gas are eliminated by passing the combustion flue gas from the outside of the filter cloth 30 covered over the outer periphery of a skeletal member 21 into the inside, and the soot and dust accumulated on the outside of the filter cloth 30 are shaken off and removed by the pulse jet introduced inside, rod-like axial members 22 of the skeletal member 21 extended in the axial direction of the bag filter forming a cross section of the filter cloth of the filter cloth structure 20 are disposed with spaces to form concave parts 31 in the cross section of the filter cloth. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pulse jet backwashing type bag filter structure used for, for example, a flue gas dust treatment of a power plant or an industrial combustion facility.

  Conventionally, in industrial combustion equipment such as coal-fired and heavy oil-fired power plants, incinerators, etc., in order to treat the flue gas dust in combustion exhaust gas generated by combustion, a pulse jet backwash type filter cloth structure is used. The provided bug filter is used. The filter cloth structure used for such a bag filter has a structure in which the outer periphery of the skeleton member is covered with a filter cloth (filter medium), and a cylindrical one having a circular cross section or an oval cross section has been used conventionally. . That is, the filter cloth structure removes the flue gas dust in the combustion exhaust gas by filtering the outer surface, and passes through the filter cloth when the combustion exhaust gas flowing from the outer surface side of the filter cloth passes through the filter cloth. Unusable flue gas dust remains on the outer surface of the filter cloth and accumulates, and only the combustion exhaust gas passing through the filter cloth is discharged through the inside of the filter cloth structure.

As described above, if the flue gas dust is filtered by the filter cloth as described above, the dust remaining after filtration will be accumulated on the filter cloth surface. It has been broken. In backwashing by pulse jet, by introducing a gas flow such as air into the inner surface of the filter cloth, the inner pressure of the filter cloth is instantaneously made higher than the outer pressure of the filter cloth, and the reverse flow of the gas flow inside the filter cloth and the swelling of the filter cloth are caused. It is used to remove dust.
The filter cloth structure 1 shown in FIG. 6 has an oval cross section, and covers the outer periphery of the skeleton member 4 in which the rod-shaped axial member 2 and the rod-shaped ring member 3 are combined in a lattice shape, and the filter cloth 5 is covered. It has been. Further, the filter cloth structure 1A shown in FIG. 7 has a circular cross section, and the filter cloth 5 is formed so as to cover the outer periphery of the skeleton member 4A in which the rod-shaped axial member 2 and the rod-shaped ring member 3 are combined in a lattice shape. It is covered.

Moreover, as a prior art of the bug filter, there is a bug filter that can prevent the harmful substance removal performance from being deteriorated even immediately after the purification cake layer is wiped off by blowing the pulse air. In this bag filter, an inner cylinder filter cloth is disposed at an interval inside the filter cloth, and the average hole diameter of the inner cylinder filter cloth is made smaller than that of the outer cylinder. (For example, see Patent Document 1)
Japanese Unexamined Patent Publication No. 2000-300924 (see FIG. 1)

  By the way, at the time of backwashing to remove dust accumulated on the filter cloth surface by the pulse jet, the deformation amount L accompanying the swelling of the filter cloth becomes important. Such a drop in dust removal performance increases the pressure loss of the bag filter. Therefore, in plants and combustion facilities that process flue gas dust using a bag filter, it becomes difficult to continue rated operation due to an increase in the pressure loss of the bag filter. Measures such as increase are necessary.

From such a background, it is desirable to increase the deformation L during backwashing in order to obtain good dust removal performance for the filter cloth that is attached to cover the filter cloth structure.
The present invention has been made in view of the above circumstances, and the object of the present invention is to provide a bag filter structure including a filter cloth structure that can increase the amount of deformation of the filter cloth and obtain good dust removal performance. Is to provide.

In order to solve the above problems, the present invention employs the following means.
The bag filter structure according to the present invention removes the flue gas dust in the combustion exhaust gas by allowing the combustion exhaust gas to pass from the outer surface side to the inner surface side of the filter cloth covered so as to cover the outer periphery of the skeleton member. In the bag filter structure equipped with a pulse jet backwash type filter cloth structure that removes the flue gas and dust accumulated on the outer surface side by a pulse jet introduced on the inner surface side, the filter cloth cross section of the filter cloth structure The rod-shaped axial members of the skeleton member that form a shape and extend in the axial direction of the bag filter are arranged at intervals so as to form a recess in the filter cloth cross-sectional shape.

  According to the bag filter structure of the present invention described above, the rod-shaped axial member of the skeleton member that forms the filter cloth cross-sectional shape of the filter cloth structure and extends in the axial direction of the bag filter has a recess in the filter cloth cross-sectional shape. Since it is arranged at intervals so as to form, if the pressure on the inner surface side becomes higher than the outer surface side due to the pulse jet introduced to the inner surface side of the filter cloth, the filter cloth of the part where the recess is formed is deformed so as to swell greatly toward the outside. To do. For this reason, during backwashing when flue gas dust accumulated on the outer surface side of the filter cloth is removed by a pulse jet, the amount of deformation from the inner surface side to the outer surface side can be increased without reducing the combustion exhaust gas passage area of the filter cloth. it can.

  The bag filter structure according to the present invention removes the flue gas dust in the combustion exhaust gas by allowing the combustion exhaust gas to pass from the outer surface side to the inner surface side of the filter cloth covered so as to cover the outer periphery of the skeleton member. In the bag filter structure having the filter cloth structure of the pulse jet backwashing method for removing the flue gas dust accumulated on the outer surface side of the filter by removing it by the pulse jet introduced on the inner surface side, the skeleton member of the filter cloth structure A spiral stretchable retainer is disposed between the filter cloth and the filter cloth. One end of the stretchable retainer is fixed near the upper end of the skeleton member, and the other end is regulated by the lower end of the skeleton member. The filter cloth is fixed to an axially movable member that slides within a range, and the filter cloth is bent at a position where the axially movable member is pulled up by the stretchable retainer.

  According to the bag filter structure of the present invention described above, a spiral stretchable retainer is disposed between the skeleton member of the filter cloth structure and the filter cloth, and one end of the stretchable retainer is near the upper end of the skeleton member. Fixed, and the other end is fixed to an axially movable member that slides within a range regulated by the lower end of the skeleton member, and a concave portion due to deflection of the filter cloth at a position where the axially movable member is pulled up by an elastic retainer When the pressure on the inner surface side becomes higher than the outer surface side due to the pulse jet introduced on the inner surface side of the filter cloth, the filter cloth and the stretchable retainer slide in the restricted range in the axial direction. It extends and deforms with the movable member. For this reason, the filter cloth is stretched and deformed so that there is no deflection. The amount can be increased.

According to the present invention described above, when the filter cloth of the filter cloth structure is compared between the normal time when pressure is applied from the outer surface side to the inner surface side and the backwash time when pressure is applied from the inner surface side to the outer surface side, the concave portion is outside. A large deformation amount L can be secured by deforming so as to bulge out or by deforming so as to extend the deflection. That is, at the time of back washing in which the smoke exhaust dust accumulated on the outer surface side of the filter cloth is removed by the pulse jet, the large amount of deformation L is secured, so that the exhaust smoke dust can be efficiently and reliably performed. In addition, the combustion exhaust gas passage area of the filter cloth does not decrease.
Therefore, the bag filter of the present invention can reduce the number of backwash times of the bag filter or reduce the amount of air consumed at the time of backwashing. You can drive.

Hereinafter, an embodiment of a bag filter structure according to the present invention will be described with reference to the drawings.
In the bag filter structure shown in FIG. 5, the bag filter 10 is connected to an inlet passage 12 for introducing combustion exhaust gas at the lower part of the dust collecting chamber 11, and discharges the combustion exhaust gas after removal of the smoke and dust (after filtration) at the upper part. The outlet channel 13 is connected. In addition, a discharge passage 14 for discharging the smoke and dust removed by backwashing is provided at the lower end of the dust collection chamber 11, and an open / close valve 15 is attached to the discharge passage 14.

Inside the dust collection chamber 11, a tubular filter cloth structure 20 that is long in the vertical direction is installed. This filter cloth structure 20 allows combustion exhaust gas to pass from the outer surface side to the inner surface side of the filter cloth 30 covered so as to cover the outer periphery of the skeleton member 21 as in the first embodiment shown in FIG. Thus, it has a filter function for removing the flue gas dust contained in the combustion exhaust gas.
In addition, a backwash pipe 16 for supplying a backwash pulse jet (a gas flow such as air) is provided on the upper part of the filter cloth structure 20 installed in the dust collecting chamber 11. The backwash pipe 16 is provided with an on-off valve 17 that opens at the time of backwashing, and a backwash nozzle 18 that ejects a pulse jet to the inner surface side of the filter cloth structure 20.

  The skeleton member 21 combines a plurality of rod-like axial members 22 extending in the axial direction (the vertical direction of the dust collecting chamber 11) and rod-like ring members 23 connected so as to surround the outer periphery of the rod-like axial member 22 in a lattice shape. It is a thing. That is, the outer periphery of the rod-shaped axial member 22 arranged in the vertical direction at a predetermined interval is connected to the wall surface portion by connecting the entire circumference by the rod-shaped ring member 23 arranged in the vertical direction with a predetermined interval in the vertical direction. It becomes the hollow columnar skeleton member 21 in which many openings are formed.

In the skeleton member 21 of the embodiment shown in FIG. 1, a cross section formed by a line connecting the members has a shape in which both short sides of the rectangle are recessed inward in a substantially semicircular shape. That is, in the illustrated example, the cross-sectional shape is formed by twelve rod-shaped axial members 22, and the portion of the rod-shaped axial member 22 that forms the substantially semicircular recess is at the end position of the opposing long side portion. It is arranged inside the line connecting the rod-shaped axial members 22.
As described above, the rod-like axial member 22 of the skeleton member 21 that forms the filter cloth cross-sectional shape of the filter cloth structure 20 and extends in the axial direction of the bag filter 10 has a spacing so as to form the recess 31 in the filter cloth cross-sectional shape. Since the filter cloth 30 placed on the skeleton member 21 is disposed, the pressure on the outer surface side of the filter cloth 30 is higher than that on the inner surface side during normal operation in which combustion exhaust gas flows from the inlet channel 12. As shown in FIG. 1 (a), the concave portion 31 is depressed inward to the position regulated by the rod-shaped axial member 22.

However, when the on-off valve 16 is opened and a pulse jet is ejected, the inner pressure of the filter cloth 30 becomes higher than the outer pressure. For this reason, the filter cloth 30 is deformed so as to bulge outward as a whole, as shown in FIG. At this time, the substantially semicircular concave portion 31 also bulges outward, that is, deforms from a concave shape directed inward to a convex shape directed outward, so that a large variation L corresponding to the diameter of the substantial circle. Can be obtained. By causing such a large deformation, the smoke exhaust dust accumulated on the outer surface side of the filter cloth 30 can be efficiently and reliably removed.
The combustion exhaust gas passage area of the filter cloth 30 is almost the same as that of the oval cross section shown in FIG. 6, so that the backwash performance can be improved while maintaining the filtration performance of the flue gas and dust. .

Next, a second embodiment according to the present invention will be described with reference to FIG.
The filter cloth structure 20A shown in FIG. 2 employs a cross-sectional shape that becomes a substantially circular cross-section during backwashing. In this case, eight rod-shaped axial members 22 are used for the skeleton member 21A, and four of them are arranged at square corners. The remaining four rod-shaped axial members 22 are arranged on the inner side of the square formed by connecting the corner portions.
Therefore, also in the case of the filter cloth structure 20A, the filter cloth 30 covered on the skeleton member 21A is shown in FIG. 2A when the outer surface side of the filter cloth 30 has a higher pressure than the inner surface side during normal operation. Thus, it becomes the recessed part 31 of the state which was pressed inward to the position regulated by the rod-shaped axial member 22, and was dented.

However, at the time of backwashing when the pulse jet is ejected, the pressure on the inner surface side of the filter cloth 30 becomes higher than the pressure on the outer surface side, so that the filter cloth 30 is generally directed outward as shown in FIG. Deforms to bulge. As a result, the filter cloth 30 is deformed from a concave shape directed inward to a convex shape directed outward and becomes a substantially circular shape, so that a large variation L can be obtained. By causing such a large deformation, the flue gas dust accumulated on the outer surface side of the filter cloth 30 can be efficiently and reliably removed.
In addition, about the combustion exhaust gas passage area of the filter cloth 30, since it is almost the same as that of the circular cross section shown in FIG. 7, the backwashing performance can be improved while maintaining the filtration performance of the flue gas and dust.

  In this way, in the bag filter structure provided with the pulse jet backwash type filter cloth structures 20 and 20A for removing the smoke and dust accumulated on the outer surface side of the filter cloth 30 by removing with the pulse jet introduced on the inner surface side. The rod-like axial members 22 of the skeleton members 21 and 21A that form the filter cloth cross-sectional shape of the filter cloth structures 20 and 20A and extend in the axial direction of the bag filter are arranged at intervals so as to form a recess in the filter cloth cross-sectional shape. As a result, when the pressure on the inner surface increases during backwashing, it is greatly deformed, and the smoke and dust can be efficiently and reliably removed.

Next, a third embodiment according to the present invention will be described with reference to FIGS.
In this embodiment, a spiral elastic retainer 40 is disposed between the skeleton member 21B of the filter cloth structure 20B and the filter cloth 30. This stretchable retainer 40 has one end fixed to the vicinity of the upper end of the skeleton member 21B and the other end fixed to the vertical moving plate 41 of the axially movable member that slides within the range regulated by the lower end of the skeleton member 21B. ing. And in the position which pulled up the up-and-down moving plate 41 with the elastic retainer 40, as shown, for example in FIG.4 (b), the recessed part 31 is formed in the filter cloth 30 by the hook-shaped bending.

  That is, when the elastic retainer 40 is spirally wound around the outer periphery of the substantially cylindrical skeleton member 21B and the pressure on the inner surface side rises during backwashing, the vertical moving plate 41 on the lower end side is lowered by this pressure. By receiving the pressing force and sliding downward, the bowl-shaped deflection formed on the filter cloth 30 is extended to eliminate the recess 31. In this case, an elastic member such as a spring is employed for the stretchable retainer 40 and urges the vertical moving plate 41 to be lifted upward.

  The mechanism for regulating the range in which the vertical moving plate 41 slides in the vertical direction includes a shaft member 42 that is fixed to the upper surface of the vertical moving plate 41 and extends upward, and a stopper 43 is attached to the upper end portion of the shaft member 42. Keep it. And this shaft member 42 is inserted in the through-hole 45 of the baseplate 44 fixed to the lower end part of the frame | skeleton member 21B, and can slide to an up-down direction. That is, the vertical movement plate 41 fixed to the lower end portion of the shaft member 42 contacts the bottom plate 44 to regulate the upper end position of the slide, and the stopper 43 fixed to the upper end portion of the shaft member 42 contacts the bottom plate 44. The lower end position of the slide is restricted.

When the inner surface side of the filter cloth 30 has a higher pressure than the outer surface side by introducing a pulse jet at the time of backwashing, the filter cloth 30 and the stretchable retainer 40 together with the vertical movement plate 41 are in the regulation range. Slide down inside. At this time, the vertical moving plate 41 serves as a pressure receiving surface on the inner surface side high pressure, and therefore receives a downward pressing force. As a result, since the filter cloth 30 and the stretchable retainer 40 are stretched and deformed, the filter cloth 30 is largely deformed so that the bowl-shaped deflection is stretched and the concave portion 31 is eliminated. Accordingly, during backwashing in which the flue gas dust accumulated on the outer surface side of the filter cloth 30 is removed by a pulse jet, the amount of deformation can be increased without reducing the combustion exhaust gas passage area of the filter cloth 30.
In this embodiment, the skeleton member 21B has a substantially circular cross-sectional shape, but may have an oval cross-sectional shape.

  Thus, the filter cloth 30 of the filter cloth structures 20, 20A, 20B has a concave portion when compared with a normal time when pressure is applied from the outer surface side to the inner surface side and a backwash time when the outer surface side pressure is received from the inner surface side. It is possible to secure a large deformation amount L by deforming so that the bulge 31 bulges out or by deforming so as to extend the deflection and eliminating the recess 31.

  For this reason, at the time of backwashing in which the smoke dust accumulated on the outer surface side of the filter cloth 30 is removed by a pulse jet, the smoke dust can be efficiently and surely removed by the large deformation amount L, and the combustion of the filter cloth The exhaust gas passage area does not decrease. Therefore, it is possible to reduce the number of backwashing times of the bag filter 10 or to reduce the amount of air consumed during backwashing, and it is possible to perform efficient operation with little pressure loss and driving power.

In addition, the configuration of the third embodiment using the stretchable retainer 40 can be combined with the configurations of the first and second embodiments in which the recess 31 is formed in the cross-sectional shape.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

It is a figure which shows 1st Embodiment which concerns on the bag filter structure of this invention, (a) is sectional drawing which shows the filter cloth structure cross-sectional shape at the time of normal time (at the time of non-backwashing), (b) is the time of backwashing It is sectional drawing which shows a filter cloth structure cross-sectional shape. It is a figure which shows the modification of the bag filter structure shown in FIG. 1, (a) is sectional drawing which shows the filter cloth structure cross-sectional shape at the time of normal time (at the time of non-backwashing), (b) is the filter cloth structure at the time of backwashing It is sectional drawing which shows a body cross-sectional shape. It is a perspective view which shows 2nd Embodiment which concerns on the bag filter structure of this invention, and the state which removed the filter cloth from the filter cloth structure is shown. It is a figure regarding the filter cloth structure shown in FIG. 3, (a) is a top view seen from the upper part of FIG. 3, (b) is an image figure which shows the filter cloth structure at the time of normal time (at the time of non-backwashing), (c ) Is an image showing the backwashing of the filter cloth structure shown in FIG. It is sectional drawing which shows the structural example of a bag filter. It is sectional drawing which shows the conventional filter cloth structure which made the cross-sectional shape the ellipse. It is sectional drawing which shows the conventional filter cloth structure which made circular cross-sectional shape.

Explanation of symbols

20, 20A, 20B Filter cloth structure 21, 21A, 21B Skeletal member 22 Rod-shaped axial member 23 Rod-shaped ring member 30 Filter cloth 31 Recess 40 Stretchable retainer 41 Vertical moving plate 42 Shaft member 43 Stopper 44 Bottom plate 45 Through hole

Claims (2)

The flue gas in the flue gas is removed by passing the flue gas from the outer surface side to the inner surface side of the filter cloth that covers the outer periphery of the skeletal member, and the flue gas dust accumulated on the outer surface side of the filter cloth In the bag filter structure equipped with the filter cloth structure of the pulse jet backwash method that removes by removing with a pulse jet introduced on the inner surface side,
The rod-shaped axial member of the skeleton member that forms the filter cloth cross-sectional shape of the filter cloth structure and extends in the axial direction of the bag filter is disposed at intervals so as to form a recess in the filter cloth cross-sectional shape. Feature bug filter structure. The flue gas in the flue gas is removed by passing the flue gas from the outer surface side to the inner surface side of the filter cloth that covers the outer periphery of the skeletal member, and the flue gas dust accumulated on the outer surface side of the filter cloth In the bag filter structure equipped with the filter cloth structure of the pulse jet backwash method that removes by removing with a pulse jet introduced on the inner surface side,
A spiral stretchable retainer is disposed between the framework member of the filter cloth structure and the filter fabric, and the stretchable retainer has one end fixed near the upper end of the framework member and the other end of the stretchable retainer. The filter cloth is fixed to an axially movable member that slides within a range restricted by a lower end portion of the skeleton member, and the filter cloth is bent at a position where the axially movable member is pulled up by the stretchable retainer. A bug filter structure.

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