JP2963331B2 - Dry electric precipitator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry electric dust collector.

[0002]

2. Description of the Related Art Conventionally, exhaust gas discharged from a boiler for coal cooking contains dust, nitrogen oxides (NO _x ), sulfur (sulfur) oxides (SO _x ) and the like. The dust is removed by an electric precipitator, the nitrogen oxides are removed by a denitrifier, and the sulfur oxides are removed by a desulfurizer.

FIG. 2 is a block diagram of a conventional exhaust gas treatment apparatus. In the figure, 11 is a coal-fired boiler,
The coal is burned by the boiler 11 to generate steam. Exhaust gas of 400 [° C.] discharged from the boiler 11 (hereinafter referred to as “gas to be treated”) includes dust,
Contains nitrogen oxides, sulfur oxides, and the like.

Therefore, the gas to be treated is first sent to a denitration device 13 where nitrogen oxides are removed. Next, the gas to be treated from which the nitrogen oxides have been removed is sent to the air preheater 15. In the air preheater 15, the gas to be treated is cooled by the combustion air of the boiler 11 to 150 ° C., and the combustion air is heated and preheated by the gas to be treated and supplied to the boiler 11. Is done.

By the way, the gas to be treated cooled in the air preheater 15 is directly supplied to a dry type electrostatic precipitator,
If the gas to be treated is supplied to the gas-gas heat exchanger after the dust is removed from the gas to be treated in the dry type electrostatic precipitator, the neutralization effect of the sulfur oxides by the dust is reduced. In this case, when the gas to be treated is cooled in the gas-gas heat exchanger, the sulfurous acid gas (S
O ₃ ) becomes mist and adheres to the surface of the gas-gas heat exchanger to corrode the gas-gas heat exchanger.

Therefore, the gas to be treated discharged from the air preheater 15 is sent to a gas-gas heat exchanger 17 in advance, cooled to 90 ° C. by the gas-gas heat exchanger 17, and then sent to a dry electric precipitator 18. I try to send. In this case, the gas to be treated is cooled in the gas-gas heat exchanger 17, but a sufficient amount of dust is present in the gas to be treated. As a result, the sulfurous acid gas does not become mist and does not adhere to the gas gas heat exchanger 17.

Next, after dust is removed from the gas to be treated in the dry type electrostatic precipitator 18, the gas to be treated is sent to a desulfurizer 20, where sulfur oxides are removed. Then, the gas to be treated discharged from the desulfurization device 20 is sent to the wet type electrostatic precipitator 22, where dust and mist remaining in the gas to be treated are removed.

Thereafter, the gas to be treated is a gas-gas heat exchanger 2
3, heated in the gas-gas heat exchanger 23, and discharged from the chimney 24. Incidentally, the dry type electrostatic precipitator 18 includes a main body (not shown) for passing the gas to be treated and sucking dust from the gas to be treated and collecting the dust, and a hopper section fixed to the main body below the main body. Having. Then, in the main body, after the dust-containing gas passes through the inlet flue, the flow velocity distribution is made uniform by the rectifier plate, and then introduced into the electric field formed between the discharge electrode and the dust collection electrode. Has become. At this time, the dust in the dust-containing gas is attracted to the dust collecting electrode by the electric force of the electric field and collected. Then, the dust sucked by the dust collecting electrode is separated (stripped) from the surface of the dust collecting electrode by the impact force of a hammer and hammer, falls, and is collected by the hopper.

FIG. 3 is a schematic diagram of a hopper of a conventional dry-type electrostatic precipitator. As shown in the figure, the hopper has an inverted pyramid-shaped iron wall 31, collects dust separated from the surface of the dust collecting electrode in a main body (not shown), and passes the dust through a dust valve 32. To the outside. By the way, the gas to be treated cooled to 90 ° C. by the gas-gas heat exchanger 17 is sent to the dry-type electrostatic precipitator 18 (FIG. 2). The dust collected in the hopper at 18 is also cooled to 90 ° C.

When the wall 31 is cooled by the atmosphere, the dust is also cooled accordingly, and sulfur oxides contained in the dust adhere to the inner surface of the wall 31 and corrode the wall 31. Would. Therefore, in order to prevent the wall body 31 from being cooled by the atmosphere, a heat insulating material 33 is provided outside the wall body 31 to perform heat insulation.

A manhole 35 is formed on the side surface of the wall 31 so that a worker can enter the hopper through the manhole 35 and perform maintenance and management inside the dry type electrostatic precipitator 18. It has become. Usually,
The manhole 35 is closed by a lid 36,
A heat insulating material 36a is adhered to 6. Further, since the collected dust adheres to the inner surface of the wall 31, the dust adheres to the inner surface of the wall 31 when the dry-type electrostatic precipitator 18 is used for a long period of time, and the dust moves downward. Will not flow smoothly. Therefore, a metal tapping seat 37 is provided with one end fixed to the side surface of the wall 31. The hitting seat 37 extends outward through the heat insulating material 33. Therefore, when the other end is hit with a hammer or the like (not shown) outside the hopper, dust adhering to the inner surface of the wall 31 is separated by an impact.

[0012]

However, in the above-mentioned conventional dry type electrostatic precipitator, a cold spot is formed by the dust valve 32, the manhole 35, the hitting seat 37, etc. of the hopper section. It becomes the starting point, causing corrosion and dust adhesion.

That is, in the dust valve 32, a metal valve main body is located between the inside and the outside of the hopper, and is supported by the wall 31. Therefore, heat is transmitted through the wall 31, and the inside of the hopper is cooled by the atmosphere. In the manhole 35, an iron sleeve 35b integral with the wall body 31 is disposed on a wall surface of a through hole 35a extending from the inside to the outside of the hopper portion.
Is exposed to the outside of the hopper and is brought into contact with the lid 36. Therefore, heat is transmitted through the iron sleeve 35b, and the inside of the hopper is cooled by the atmosphere.

Further, heat is transmitted through the metal hitting seat 37, and the inside of the hopper is cooled by the atmosphere. As described above, many cold spots are formed in the hopper, and dust near the cold spots is cooled by the atmosphere.
Corrosion or dust adhesion occurs in the hopper.

Also, in the main body, if the gas to be processed passing through the inside of the main body is cooled by the atmosphere through the wall, drain is generated. The present invention solves the above-mentioned problems of the conventional dry type electrostatic precipitator, and does not cause corrosion or adhesion of dust in a hopper portion, and does not generate drain in a main body portion. It is intended to provide a dry electric precipitator.

[0016]

For this purpose, the dry electric precipitator of the present invention is disposed downstream of the gas-gas heat exchanger in the feed direction of the gas to be treated and upstream of the desulfurizer, An electric field is formed between the discharge electrode and the dust collecting electrode, a main body for removing the dust from the gas to be treated by sucking the dust to the dust collecting electrode, and collecting the dust disposed below the main body. And a hopper portion.

The hopper is provided with a metal member divided into an inner portion and an outer portion between the inside and the outside of the hopper portion. A heat insulating material is provided in the vehicle. Another dry-type electrostatic precipitator of the present invention is disposed downstream of the gas-gas heat exchanger in the feed direction of the gas to be treated and upstream of the desulfurizer, and is provided between the discharge electrode and the precipitating electrode. An electric field is formed, a main body for removing dust from the gas to be treated by sucking the dust to the dust collecting electrode, a hopper disposed below the main body and collecting the dust, and the discharge electrode. And an insulator chamber in which an insulator for supporting is accommodated.

Further, a heat insulating material is provided between the main body and the insulator chamber, and between the main body and the hopper.

[0019]

According to the present invention, as described above, the dry type electrostatic precipitator is disposed downstream of the gas-gas heat exchanger in the feed direction of the gas to be treated and upstream of the desulfurizer. An electric field is formed between the dust collecting electrode and the main body for removing dust from the gas to be treated by attracting dust to the collecting electrode, and disposed below the main body to collect dust. And a hopper.

After the gas to be treated is cooled by the gas-gas heat exchanger, it is sent to a dry electric dust collector, where dust is removed from the gas to be treated. In the hopper portion, a metal member divided into an inner portion and an outer portion is disposed between the inside and the outside of the hopper portion, and a heat insulating material is provided between the inner portion and the outer portion of the metal member. Will be arranged. In this case, it is possible to prevent heat from being transmitted through the metal member.

Another dry-type electrostatic precipitator of the present invention is disposed downstream of the gas-gas heat exchanger in the feed direction of the gas to be treated and upstream of the desulfurization unit. A body portion for forming an electric field therebetween and removing dust from the gas to be treated by sucking the dust to the dust collecting electrode, a hopper portion disposed below the body portion and collecting dust, And an insulator chamber accommodating an insulator for supporting the discharge electrode.

Further, a heat insulating material is provided between the main body and the insulator chamber, and between the main body and the hopper. In this case, it is possible to prevent heat from being transmitted between the main body and the insulator chamber and between the main body and the hopper.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic view of a hopper portion of a dry type electrostatic precipitator according to a first embodiment of the present invention. In the figure, the hopper has an inverted pyramid-shaped iron wall 31 and collects dust separated from the surface of the dust collecting electrode in a main body (not shown) of the dry electric precipitator 18 (see FIG. 2). Then, the dust is discharged to the outside via the dust valve 32.

Incidentally, the gas to be treated cooled to 90 ° C. by the gas-gas heat exchanger 17 is sent to the dry electric dust collector 18.
The dust collected by the hopper in the dry electric precipitator 18 is also cooled to 90 ° C. When the wall 31 is cooled by the atmosphere, the dust is also cooled accordingly, and sulfur oxides contained in the dust adhere to the inner surface of the wall 31 and corrode the wall 31. Therefore, in order to prevent the wall body 31 from being cooled by the atmosphere, a heat insulating material 33 is provided outside the wall body 31 to perform heat insulation.

A manhole 55 is formed on the side surface of the wall 31 so that a worker can enter the hopper through the manhole 55 to perform maintenance and inspection of the dry electric precipitator 18. It has become. Usually,
The manhole 35 is closed by a lid 56,
A heat insulating material 56a is adhered to 6. Furthermore, since the collected dust adheres to the inner surface of the wall 31, the dust adheres to the inner surface of the wall 31 when the dry dust collector 18 is used for a long period of time, and the dust smoothly moves downward. It stops flowing. Therefore, a metal hitting seat 57 is provided with one end fixed to the side surface of the wall 31. The hitting seat 57 extends outward through the heat insulating material 33. Therefore, when the other end is hit with a hammer or the like (not shown) outside the hopper, dust adhering to the inner surface of the wall 31 is separated by an impact.

Incidentally, the dust valve 3 is provided in the hopper.
2. Since the manhole 35, the hitting seat 37 and the like are provided from the inside of the hopper to the outside, a cold spot is formed when the inside heat is transferred to the outside. Therefore, in the vicinity of the dust valve 32, the wall 3
1 is cut perpendicularly in the axial direction to divide it into an inner portion and an outer portion, and a gasket 61 made of a heat insulating material such as rubber is provided between the two. In this way, heat can be prevented from being transmitted through the heat insulating material 33. The wall 31 has a flange 31a in the circumferential direction of the gasket 61,
31b is formed, the gasket 61 is sandwiched between the flanges 31a and 31b, and fixed by bolts or the like (not shown). In this case, it is possible to prevent heat from being transmitted between the flanges 31a and 31b by forming the bolts and the like with a heat insulating material.

In the manhole 55, a wall surface of a through hole 55a extending from the inside to the outside of the hopper portion is provided.
An iron sleeve 55b integral with the wall 31 is provided, and one end of the sleeve 55b is exposed to the outside of the hopper and is brought into contact with the lid 56. Therefore, the sleeve 55b is cut perpendicularly in the axial direction and divided into an inner portion and an outer portion, and a gasket 63 made of a heat insulating material such as rubber is provided between the two. In this way, heat can be prevented from being transmitted through the sleeve 55b. The sleeve 55b is formed with flanges 55b ₁ and 55b ₂ in the circumferential direction of the gasket 63.
5b ₁ , 55b ₂ sandwich the gasket 63,
It is fixed by bolts or the like (not shown). In this case, the bolts are formed of a heat insulating material, and the flanges 55 b ₁ , 5 b
Heat can be prevented from being transmitted in between 5b _2.

Further, the tapping seat 57 made of metal is cut perpendicularly in the axial direction to divide it into an inner portion and an outer portion, and a gasket 65 made of a heat insulating material is provided between the two. In this way, it is possible to prevent heat from being transmitted through the hitting seat 57. Further, flanges 57a and 57b are formed in the striking seat 57 in the circumferential direction of the gasket 65, and the gasket 65 is sandwiched between the flanges 57a and 57b and fixed with bolts or the like (not shown). in this case,
The bolt is formed of a heat insulating material, and the flange 57a,
It is possible to prevent heat from being transmitted between the portions 57b.

As described above, heat is prevented from being transmitted to the dust valve 32, the manhole 55, the hitting seat 57, and the like, and the inside of the hopper can be prevented from being cooled by the atmosphere. Therefore, since no cold spot is formed in the hopper, no corrosion occurs and no dust adheres.

In this case, the wall body 31 and the sleeve 55b are cooled by the atmosphere in the portion outside the gaskets 61 and 63, and corrosion may occur. However, the wall body 31 and the sleeve 55b outside the gaskets 61 and 63 can be easily replaced by removing bolts. Next, a second embodiment of the present invention will be described.

FIG. 4 is a conceptual diagram of a dry-type electrostatic precipitator according to a second embodiment of the present invention. As shown in the figure, the dry type electrostatic precipitator 18 includes a main body 71 and a hopper 72, and a gas to be processed flows in the main body 71 in the direction of arrow A.
A discharge electrode and a dust collecting electrode (not shown) are provided in the main body 71, and the dust of the gas to be processed is sucked into the dust collecting electrode.
Further, an insulator chamber 76 is formed at an upper end of a wall 75 of the main body 71, and an insulator (not shown) is provided in the insulator chamber 76.
The discharge electrode is supported by the insulator.

On the other hand, a hopper 72 is formed at the lower end of the wall 75 of the main body 71, and dust removed from the gas to be processed is collected in the hopper 72. Since the insulator chamber 76 and the hopper 72 are formed so as to protrude from the main body 71, the insulator chamber 76 and the hopper 72 are easily cooled by the air and easily cooled. Therefore, a heat insulating material 81 is provided between the wall 75 and the insulator chamber 76.
The heat insulating material 82 between the wall 75 and the hopper 72
Accordingly, the intermediate portion of the hopper 72 is separated by the heat insulating material 83 to prevent the inside of the dry electrostatic precipitator 18 from being cooled by the atmosphere.

Therefore, it is possible to prevent the generation of drain in the dry type electrostatic precipitator 18. It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made based on the gist of the present invention.
They are not excluded from the scope of the invention.

[0034]

As described above in detail, according to the present invention, the dry electric precipitator is disposed downstream of the gas gas heat exchanger in the feed direction of the gas to be treated and upstream of the desulfurizer. A main body for forming an electric field between the discharge electrode and the dust collecting electrode, removing dust from the gas to be treated by sucking the dust to the dust collecting electrode, and disposed below the main body;
And a hopper for collecting dust.

In the hopper, a metal member provided between the inside and the outside of the hopper is divided into an inner portion and an outer portion, and a heat insulating material is provided between the inner portion and the outer portion. Is established. In this case, it is possible to prevent heat from being transmitted through the metal member. Therefore,
Since no cold spot is formed in the hopper, corrosion and dust do not occur.

Another dry-type electrostatic precipitator of the present invention is disposed downstream of the gas-gas heat exchanger in the feed direction of the gas to be treated and upstream of the desulfurization unit. A body portion for forming an electric field therebetween and removing dust from the gas to be treated by sucking the dust to the dust collecting electrode, a hopper portion disposed below the body portion and collecting dust, And an insulator chamber accommodating an insulator for supporting the discharge electrode.

Further, a heat insulating material is provided between the main body and the insulator chamber, and between the main body and the hopper. In this case, it is possible to prevent heat from being transmitted between the main body and the insulator chamber and between the main body and the hopper. Therefore, it is possible to prevent the generation of drain in the dry electric precipitator.

[Brief description of the drawings]

FIG. 1 is a schematic view of a hopper section of a dry electric precipitator according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a conventional exhaust gas treatment device.

FIG. 3 is a schematic view of a hopper of a conventional dry-type electrostatic precipitator.

FIG. 4 is a conceptual diagram of a dry electric precipitator according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 17 gas gas heat exchanger 18 dry electric precipitator 20 desulfurizer 33, 81, 82, 83 thermal insulator 71 main body 72 hopper 76 insulator room

Claims (2)

(57) [Claims] 1. A dry electric precipitator disposed downstream of a gas gas heat exchanger in a feed direction of a gas to be treated and upstream of a desulfurizer, wherein: (a) a discharge electrode and a dust collecting electrode; (B) forming an electric field between the main body and the main body for removing the dust from the gas to be treated by sucking the dust to the dust collecting electrode;
A hopper portion disposed below the main body portion for collecting dust; and (c) the hopper portion is divided into an inner portion and an outer portion between the inside and the outside of the hopper portion. (D) a heat insulating material is provided between an inner portion and an outer portion of the metal member. 2. A dry electric precipitator disposed downstream of a gas gas heat exchanger in a feed direction of a gas to be treated and upstream of a desulfurizer, wherein: (a) a discharge electrode and a dust collecting electrode; (B) forming an electric field between the main body and the main body for removing the dust from the gas to be treated by sucking the dust to the dust collecting electrode;
A hopper portion disposed below the main body portion for collecting dust, and (c) an insulator chamber accommodating an insulator for supporting the discharge electrode; A dry electric precipitator, wherein a heat insulating material is provided between the chamber and the main body and the hopper.