JP3035128B2 - Dust remover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust removing device, and more particularly to a dust removing device for a high-temperature dust-containing gas discharged from a combustion facility using a fossil fuel such as coal.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional dust removing apparatus for a high-temperature dust-containing gas provided with a porous ceramic filter element. A dust-containing gas inlet 2 is provided at an upper portion of the can body 1 arranged substantially vertically, and a dust hopper 3 is provided at a lower portion thereof. In the can 1, a filter element 5 of a honeycomb type porous ceramic body is provided.
A first filter portion 4 which is arranged annularly in the flow direction of the inside and forms a dust-containing gas passage 1 ′ therein, and a recess portion 9 of the can body 1 at a portion below the first filter portion 4. The second filter element 7 is provided with a honeycomb-type porous ceramic body and is arranged in the flow direction in the can body 1.
A filter unit 6 is provided. The dust-containing gas introduced into the can 1 from the dust-containing gas inlet 2 flows downward in the can 1 and is removed by the first filter unit 4 to become a clean gas. Flows downward, and is removed by the second filter unit 6 to become a clean gas, and the dust is removed from the can body 1.
Is stored in the dust hopper 3 at the lower part of the can body 1 and taken out of the can body 1 as appropriate.

At the substantially vertical center of the first filter section 4, a clean gas pipe 8 is opened in the can 1, and the clean gas pipe 8 is connected to the recess section 9 via a conduit 8 '. The clean gas removed by the first filter section 4 and the second filter section 6 is taken out of the can 1 through a clean gas pipe 8.

In order to backwash dust adhering to the filter elements of the respective filter sections 4 and 6, the first filter section 4 and the second filter section 6 are provided in the clean gas pipe 8 and the conduit 8 ', respectively. Backwash nozzle 1 opening toward
The nozzles 14 and 14 are connected to the high-pressure air source 11 through a backwash air pipe 12 having an air-operated on / off valve 13. By opening and closing the on / off valve 13, the backwashing nozzle 14 blows backflow air toward the filter element of the first filter unit 4 or the second filter unit 6 during an appropriate period. Backwashing is performed.

[0005]

In the above-mentioned conventional dust removing apparatus, backwashing is performed periodically and intermittently.
For this reason, at the time of backwashing, after high-pressure air is blown out from the backwash nozzle, the on / off valve of the backwash air is fully closed and remains as it is until the next backwash. Since the on-off valve itself is disposed outside the can body, the heat release lowers the backwash air pipe and the air temperature in the pipe. On the other hand, when processing a high-temperature dust-containing gas such as a gas obtained by burning a fossil fuel such as coal containing sulfur, high-temperature gas will enter from the tip of the backwash nozzle, and during long-term operation or At the time of starting and stopping, there is a possibility that corrosion occurs in the on / off valve seat portion or the inner surface of the nozzle main body due to the sulfur content and the like contained in the high-temperature gas.

The on / off valve is an air-operated automatic valve, but a quick motion is required for opening and closing in order to generate a pulse-like pressure wave at the time of backwashing and to enhance the effect of backwashing. . Polytetrafluoroethylene (Teflon) resin or the like is usually used as a valve seat material that can withstand this need, and a metal material suitable for this purpose is expensive and has sufficient reliability. The fact is that I can't say it. Accordingly, a resin such as polytetrafluoroethylene must be selected as a seat material of the on / off valve. However, the temperature is limited to 300 ° C. or less due to temperature limitation.

[0007] Since the backwash nozzle in the dust remover that treats high-temperature dust-containing gas is exposed to a high temperature of about 800 ° C,
The heat conduction through the pipe metal is large, while the on-off valve must be installed as close to the backwash nozzle as possible to shorten the high-speed gas flow section and reduce the pressure loss of the pipe. The temperature limitation of the sheet material is a serious problem.

The present invention has been made to solve the above problems.

[0009]

The dust removing device of the present invention takes the following measures. (1) A dust-containing gas inlet at the upper part, and a lower part connected to a dust hopper or a lower part with a built-in dust hopper, and one or a plurality of filter parts arranged in a substantially vertical direction in a flow direction. The filter unit is a dust removal device composed of a porous ceramics filter element. In the dust removing device, dust adhering to the filter element for filtering dust-containing gas is periodically back-washed from a back-wash nozzle for each filter unit. The backwashing device that introduces and removes the working air, bypasses the backwashing air on / off valve provided in the middle of the backwashing air pipe equipped with a backwashing nozzle, and has at least one of an orifice and a manual control valve. A purge system equipped with a purge system is provided. (2) In the dust removing device of the above (1), a portion of the back washing air pipe from the on / off valve of the back washing air of the back washing device to the back washing nozzle, and the dust removing device or the cleaned clean gas flows. The cooling means is attached to a portion outside the clean gas pipe.

[0010]

[Action]

(1) In the present invention of (1), a purge system is provided to bypass an on / off valve of a backwash air pipe having a backwash nozzle, and an orifice and / or a manual control valve are provided in the purge system. Accordingly, the required amount of purge air always flows downstream of the on / off valve. Therefore, during the normal operation of the dust removing apparatus in which the on / off valve is closed and the backwash nozzle does not blow out the backwash air, hot gas does not enter the backwash air pipe from the backwash nozzle. This eliminates the possibility of corrosion due to sulfur and the like, and reduces the temperature of the air downstream of the on / off valve to the same low temperature as the temperature of the high-pressure air source upstream, for example, 200 ° C. The temperature is kept below the temperature. (2) The backwash nozzle is in the dust removing device main body or the clean gas pipe after dust removal and is always exposed to high-temperature gas, and the heat is transmitted to the upstream backwash air on / off valve through the backwash air pipe. It will be transmitted. In the present invention (2), the cooling means is attached to the part of the backwash air pipe from the on / off valve to the backwash nozzle and to the part outside the dust removing device or the clean gas pipe through which the clean gas from which dust has been removed flows. Therefore, heat conduction from the backwash nozzle to the on / off valve can be prevented, and the on / off valve can be reliably maintained at a low temperature.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. In this embodiment, the first filter unit and the backwashing device are different from the conventional dust removing device shown in FIG. 3 as described below, and the same parts are denoted by the same reference numerals in FIG. 1 as those in FIG. And the description is omitted.

The first filter section 4 arranged in the can body 1 in the present embodiment is constituted by arranging a plurality of filter elements 5 each formed of a cylindrical porous ceramic body arranged substantially vertically. The upper and lower ends of the filter elements 5 are attached to the tube sheet 5a, respectively, and the dust-containing gas is removed while flowing through each filter element 5 and passing through the filter element 5 from the inside to the outside. As a result, the dust-containing gas containing dust is guided into the clean gas pipe 8 and flows downward to be guided from the filter element 5 to the lower portion of the can body 1.

A purge air pipe 15 that connects the high pressure air source 11 and the backwash nozzle 14 and has an on / off valve 13 is provided with a purge air pipe 15 that bypasses the on / off valve 13.
The purge air pipe 15 has a manual control valve 16 and an orifice 17 for constantly flowing a required amount of purge air. Further, the on / off valve 13 of the backwash air pipe 12 and the backwash nozzle 1
Radiation fins 18 formed by welding a large number of thin ring-shaped fins are provided on the surface of the portion outside the clean gas pipe 8 between the four.

In this embodiment, the backwash air pipe 12 is provided with a purge air pipe 15 which bypasses the on / off valve 13 and the orifice 17 or the manual control valve 16 of the purge system 15 is adjusted in advance. The required amount of purge air always flows downstream of the on / off valve 13, and hot clean gas does not enter the backwash nozzle 14. Therefore, the backwash air pipe 12 and the on / off valve 13 are kept at a low temperature and are protected from being corroded by sulfur in the high-temperature gas.

Although the heat of conduction from the backwash nozzle 14 to the on / off valve 13 is reduced by the purge air, the backwash air between the on / off valve 13 and the backwash nozzle 14 having a heat resistance limit of 300 ° C. Radiation fins 1 on tube 12
Due to the provision of 8, the on / off valve 13 is more reliably protected.

A second embodiment of the present invention will be described with reference to FIG. FIG. 2 is an enlarged view of a portion corresponding to the portion A in FIG. 1. The second embodiment has no difference from the first embodiment except for the portions described below. This embodiment is directed to a radiation fin 1 provided in the backwash air pipe of the first embodiment.
8, a portion of the backwash air pipe 12 outside the clean gas pipe 8 between the on / off valve 13 and the backwash nozzle 14
A cooler 19 for circulating cooling water for cooling the surface is provided, and a cooling water inlet valve 2 is provided on one side of the cooler 19.
0, and a cooling water outlet valve 21 on the other side.
Is connected to a cooling water outlet pipe provided with cooling water, and cooling is performed by supplying cooling water.

In this embodiment, the same operation and effect as those of the first embodiment can be obtained.

[0018]

As described above, the present invention provides a purge system for bypassing the on / off valve of a backwash air pipe for supplying backwash air to a backwash nozzle of a backwash apparatus, and the same system is provided with an orifice. And at least one of the manual valves,
Further, since the cooling means is attached to the portion between the on / off valve of the backwash air pipe and the backwash nozzle and to the portion outside the dust removing device or the clean gas pipe, the following effects can be obtained. The reliability of the dust removing device can be improved. (1) By constantly flowing air bypassing the on / off valve, entry of high-temperature gas from the backwash nozzle into the backwash air pipe can be prevented, and sulfur in the backwash air pipe and the on / off valve can be prevented. The problem of corrosion due to minutes etc. is eliminated. In addition, since the air flowing by-passing the on / off valve is at a low temperature, the inside of the backwash air pipe has a low-temperature atmosphere, which reduces the high-temperature heat conduction to the on / off valve and may cause high-temperature damage to the seat of the on / off valve. Can be eliminated. (2) The temperature increase of the on / off valve due to heat conduction from the backwash nozzle exposed to a high-temperature gas, for example, a gas having a temperature exceeding 800 ° C., is prevented by a cooling means attached to the backwash air pipe; The temperature of the on / off valve can be further lowered, and the degree of safety can be further increased in combination with the effect (1).

[Brief description of the drawings]

FIG. 1 is an overall view of a dust removing apparatus according to a first embodiment of the present invention.

FIG. 2 shows the second embodiment of the present invention and is an enlarged view of a portion corresponding to a portion A in FIG.

FIG. 3 is an overall view of a conventional dust removing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 can body 2 dust-containing gas inlet 3 dust hopper 4 first filter section 5 filter element 6 second filter section 7 filter element 8 clean gas pipe 9 recess section 11 high-pressure air source 12 backwash air pipe 13 on-off valve 14 backwash Nozzle 15 Purge air pipe 16 Manual control valve 17 Orifice 18 Radiation fin 19 Cooler 20 Cooling water inlet valve 21 Cooling water outlet valve

Continued on the front page (72) Inventor Tetsuya Fujino 1-1 1-1 Akunoura-cho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (72) Inventor Yuichiro Kitagawa 1-1, Akunoura-cho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (56) References JP-A-4-326916 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 46/00-46/54

Claims (2)

(57) [Claims] A dust-containing gas inlet is provided at an upper portion, and a lower portion is connected to a dust hopper or a lower portion has a built-in dust hopper. In a dust removing device having a filter portion, the filter portion is made of a porous ceramics filter element, and dust adhering to a filter element for filtering dust-containing gas is periodically removed from a backwash nozzle for each filter portion. The backwashing device that introduces and removes the backwashing air, bypasses the backwashing air on / off valve provided in the middle of the backwashing air pipe with the backwashing nozzle, and has at least an orifice and manual control valve. A dust remover, comprising a purge system provided with any of the above. 2. A part of a backwash air pipe from an on / off valve of a backwash air of a backwash apparatus to a backwash nozzle, and outside a dust remover or a clean gas pipe through which clean dust gas flows. The cooling means is attached to the portion.
3. The dust removing device according to 1.