JPH06190230A - Dust removing device - Google Patents

Abstract

PURPOSE:To lessen the dust deposited on the inner surface of ceramics tubes by securing dust contg. gas flow meter the lowest end of the ceramics tubes without installing special equipment, such as a circulating line and a circulating pump. CONSTITUTION:The upper and lower ends of plural porous ceramics tubes 2a, 2b almost vertically arranged inside a can body 1 are supported by tube sheets 3. The inside of the can body 1 is divided into an upper space 5 communicating with a dust-contg. gas inlet 9 in the upper part, a central space 7 communicating with a clean gas outlet pipe 6 in the intermediate part and a lower space 9 communicating with a dust hopper 8 in the lower part. Dust is removed while the dust contg.-gas 10 passes through the ceramics tubes 2a, 2b from the inside to the outside to form a dust removing device. And a part of the plural porous ceramics tubes are made the upper end closed type ceramics tubes 2b and the remainder are made of the two ends open type ceramics tubes 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust remover, and more particularly to a dust remover for high temperature gas which is effective when applied to a coal-fired combined cycle power plant and the like.

[0002]

2. Description of the Related Art In order to remove dust in high temperature gas, a dust removing device using a porous ceramics tube has recently attracted attention. FIG. 5 shows an example of the related art. The dust removing device is a can body 1.
Includes. The upper and lower ends of a plurality of open-ended porous ceramic tubes 2 arranged substantially vertically inside the can body 1 are supported by tube plates 3, respectively. The inside of the can body 1 is partitioned into an upper space 5 communicating with an upper dust-containing gas inlet 4, a central space 7 communicating with an intermediate clean gas outlet pipe 6, and a lower space 9 communicating with a lower dust hopper 8. ing.
The dust-containing gas 10 such as the boiler combustion gas is removed while passing from the inside to the outside of each ceramic pipe 2, and flows from each clean gas outlet pipe 6 to the clean gas pipe 11.

Further, in order to remove dust adhering to the ceramics tube 2, high pressure air for backwashing is intermittently supplied from a compressed air source 12 through a backwash valve 13 and an air tube 14, and each clean gas is supplied from a nozzle 15. It is adapted to be injected into the central space 7 of the can body 1 through the outlet pipe 6.

In the conventional dust remover described above, however, the plurality of ceramic tubes 2 are only open at both ends, and the clean gas from which dust has been removed is extracted horizontally through the ceramic tube wall. At the lowermost portion (outlet) D of each ceramic tube, there is no downward gas flow as shown in FIG. 6 (the heights of A to D correspond to A to D of FIG. 1, respectively), and at the upper part of the ceramic tube. The dust that has peeled off falls and stagnates, making it difficult to discharge the dust to an ash processing device (not shown) located downstream of the dust hopper 8. And
In extreme cases, there is concern that the ceramic tube may be blocked by dust. Furthermore, abnormal combustion occurs in the upstream boiler, etc.
If dust containing unburned matter stagnates at the lowermost end of the ceramic tube, there is a concern that afterburning phenomenon may occur when backwashing air is introduced.

As a conventional example that solves these problems, there is one disclosed in Japanese Patent Publication No. 3-24251. In this conventional example, as shown in FIG. 7, in order to secure the gas flow in the lowermost end portion of the ceramic tube 2,
A dust-containing gas circulation line 16 from the lower space 9 to the upper space 5 of the can body 1 is provided, and a circulation pump 17 is provided in this line. In FIG. 7, the same parts as those shown in FIG. 5 are designated by the same reference numerals, and the duplicated description will be omitted.

[0006]

However, the conventional example shown in FIG. 7 has the following problems. That is, there is no existing circulation pump that can withstand a high temperature gas of 800 ° C., and it is difficult to put it into practical use. Moreover, even if it can be put to practical use, the efficiency of the dust remover itself is lowered by circulating the gas.

The present invention has been made in order to solve the problems of the prior art, and the dust-containing gas flow in the vicinity of the lowermost end of the ceramic tube can be achieved without providing a special device such as a circulation line or a circulation pump. It is an object of the present invention to provide a dust removing device that secures the above-mentioned conditions and has less dust accumulation on the inner surface of the ceramic tube.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention supports the upper and lower ends of a plurality of porous ceramics tubes arranged substantially vertically inside a can body by tube plates, The inside of the can is partitioned into an upper space that communicates with the upper dust-containing gas inlet, a central space that communicates with the intermediate clean gas outlet pipe, and a lower space that communicates with the lower dust hopper. In a dust removing device adapted to remove dust while passing through, a part of the plurality of porous ceramics tubes is an upper end sealed ceramics tube, and the rest is an open both ends ceramics tube.

[0009]

According to the above-mentioned means, the dust-containing gas which has reached the lower space through the both ends open type ceramics tube is turned back and flows into the upper end sealed type ceramics tube from the lower side, and is removed while it goes out from the inside to the outside. It becomes clean gas and reaches the central space. As a result, a gas flow can be secured even at the lowermost end (exit) of the open-ended ceramics tube, and dust accumulation due to stagnation of the gas flow in the ceramics tube can be reliably prevented.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of the dust remover according to the present invention, the same parts as those shown in FIG. 5 are designated by the same reference numerals, and the duplicated description will be omitted.

As shown in FIG. 1, according to the present invention, a plurality of porous ceramics tubes disposed inside the can body 1 of the dust removing device include a ceramics tube 2a open at both ends and an upper end closed type (lower end is (Open) ceramic tube 2b. When the ceramic pipes are arranged in two stages (or three or more stages) in the vertical direction as in this embodiment, the upper end sealed ceramic pipe 2b is arranged in the lowermost stage.

FIG. 2 is an enlarged view of a part of FIG. 1 and shows in detail an example of a connecting portion of the upper end hermetically sealed ceramics tube 2b to the tube plate 3. Ceramic tube 2 inserted in tube hole of tube plate 3
The closed upper end of b is held by a holding lid 22 with a cushioning material 21 such as a ceramics fiber sandwiched between the tops to prevent the ceramics tube 2b from rising due to gas pressure. Presser lid 2
2 is fixed to the tube sheet 3 with bolts 23.

Next, the operation will be described. In FIG. 1, a dust-containing gas 10 such as a boiler combustion gas is indicated by a dust-containing gas inlet 4
Is introduced into the upper space 5 of the can body 1, flows into the open-ended ceramics tube 2a, and flows downward. During that time, most of the dust-containing gas 10 passes through the ceramic tube wall to become clean gas and reaches the central space 7, but a part of the dust-containing gas passes through the ceramic tubes 2a with both ends open and reaches the lower space 9, and from here. U-turn and upper end sealed ceramic tube 2
flow into b.

Then, the dust-containing gas 10 'flowing into the upper end sealed ceramics tube 2b passes through the ceramics tube wall while rising and becomes clean gas to reach the central space 9, and the above-mentioned open-ended ceramics tube 2a is piped. It joins the clean gas that has passed through the wall and is sent to the clean gas outlet pipe 6.

According to the dust remover having the above-described structure, the gas flow velocities in the both-end open type ceramics tube 2a and the upper end hermetically-sealing type ceramic tube 2b are as shown by the solid line A and the dotted line B in FIG. A sufficient gas flow velocity can be obtained even at the lowermost portion D of the shaped ceramics tube 2b. 3 indicates the case of the conventional device, and A to D correspond to the heights of A to D in FIG. 1, respectively.

However, it is advantageous that the downward gas flow velocity at the lowermost end of the open-ended ceramics tube is large in view of the fall of dust. On the other hand, when considering the fall of dust in the top closed ceramics tube, it cannot be increased unnecessarily due to the relationship between the rising speed of the dust-containing gas and the drop limit particle size of dust shown in FIG. Therefore, considering these, it is most practical to select the downward gas flow velocity as 0.5 to 2 m / s.

As a concrete example, 63 ceramic tubes are provided in each of the upper and lower stages in the inside of the can body 1, and 10 tubes in the lower and inner stages thereof are made into upper end sealed type ceramic tubes 2b, whereby both ends open type ceramics. The lowermost part D of the pipe 2a
In the above, it was possible to secure a downward gas flow velocity of about 1 m / s, and as a result, it was possible to promote the fall of the dust on the inner surface of the ceramic tube and reliably prevent the dust from accumulating on the same portion.

[0018]

As described above, according to the present invention, in a dust removing device using a plurality of porous ceramic tubes,
By combining the ceramics tube with both ends open type and the top end closed type ceramics tube, it is possible to secure the gas flow velocity in the vicinity of the lowermost end of the both ends open type ceramics tube, so dust accumulation and clogging in the ceramics tube can be ensured. Can be prevented. Further, unlike the conventional case, a dust-containing gas circulating device (such as a circulating pump capable of withstanding high temperatures) is not required, so that the dust-removing device can be simplified and the efficiency does not decrease due to circulation. Therefore, according to the present invention, it is possible to realize an inexpensive dust removal device with high efficiency as a whole.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a dust removing device according to the present invention.

FIG. 2 is a cross-sectional view showing a detail of an example of an enlarged portion of FIG. 1 in which an upper end sealed ceramics tube is attached to a tube plate.

FIG. 3 is a diagram showing a gas flow velocity distribution inside the ceramic tube of FIG.

FIG. 4 is a diagram showing the relationship between the rising flow rate of dust-containing gas and the particle size limit of dust fall.

FIG. 5 is a schematic sectional view showing an example of a conventional dust remover.

FIG. 6 is a diagram showing a gas flow velocity distribution inside the ceramic tube of FIG.

FIG. 7 is a schematic cross-sectional view showing another example of a conventional dust remover.

[Explanation of symbols]

 1 can body 2a open both ends type ceramics tube 2b top closed type ceramics tube 3 tube plate 4 dust-containing gas inlet 5 upper space 6 clean gas outlet pipe 7 central space 8 dust hopper 9 lower space 10 dust-containing gas 11 clean gas pipe 12 compression Air source 13 Backwash valve 14 Air tube 15 Nozzle 21 Cushioning material 22 Presser lid 23 Bolt

(72) Inventor Yuichiro Kitagawa 1-1, Atsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard (72) Inventor Takuma 1-1, Atsunoura-cho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Ltd. Company Nagasaki Shipyard

Claims (3)

[Claims] 1. The upper and lower ends of a plurality of porous ceramics tubes arranged substantially vertically inside a can body are supported by tube plates, respectively.
An upper space leading to the dust-containing gas inlet on the inside of the can body,
In the dust removing device, which is divided into a central space leading to the clean gas outlet pipe in the middle portion and a lower space leading to the dust hopper in the lower portion, and dust is removed while the dust-containing gas escapes from the inside to the outside of the ceramic pipe, A dust remover characterized in that a part of the porous ceramics tube is an upper end sealed ceramics tube, and the rest is open-ended ceramics tube. 2. The dust remover according to claim 1, wherein a plurality of porous ceramic tubes are vertically arranged inside the can body. 3. The number of closed upper end type ceramics tubes is set so that the downward dust-containing gas flow velocity at the lowermost end of the open end type ceramics tube is 0.5 to 2 m / s. Or the dust removing device according to 2.