JP2000061351A - Wet electric dust collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the moisture, after condensation, contained in exhaust gas adhere to the surface of a dust collector, and to make the condensed water flow down along the surface of a dust collecting electrode so as to wash down dust adhering to the surface thereof, by constituting the dust collector so as to cool the dust collecting electrode with a circulating cooling medium. SOLUTION: Two electrode plates 15 and 16 are parallelly arranged to face each other, and both sides of these electrode 15 and 16 are liquid-tightly connected with a connection member 17 over the full length of the both sides, thereby a cooling medium passage 18 is formed between the electrode plates 15 and 16 to constitute a dust collecting electrode 19. Moreover a number of dust collecting electrodes 19 are installed in a wet electric dust collector 20, and the cooling medium passage 18 in each the dust collecting electrodes 19 is connected to a cooling medium pipes 22 and 23, a cooling medium circulating pump 24, and a cooling medium circulation system 21 equipped with a cooling machine 5. In such a constitution, a cooling medium 26 such as water cooled with the cooling machine 25 of the cooling medium circulation system 21 is circulated into the dust collecting electrodes 19 to cool them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrostatic precipitator.

[0002]

2. Description of the Related Art In an exhaust gas treatment facility or the like, the dust contained in the desulfurized exhaust gas is removed by a wet electrostatic precipitator and then discharged.

FIG. 3 is a schematic diagram showing an example of an exhaust gas treatment apparatus. Exhaust gas discharged from a boiler 1 is subjected to heat recovery by a heat recovery unit 2 of a gas gas heater, and then dust is removed by an electric dust collector 3. Wet flue gas desulfurization device 5 by induction draft fan 4
In order to prevent white smoke, it is heated by the reheater 7 of the gas gas heater and discharged from the chimney 8 after it is desulfurized and the dust is removed again by the wet electrostatic precipitator 6.

FIG. 4 is a detailed view of the IV portion of FIG. 3, in which the wet flue gas desulfurization apparatus 5 circulates the absorbing liquid 9 by the pump 10 and sprays it from the spray 11 and introduces the exhaust gas 12
Absorbs sulfur oxides from.

The exhaust gas 12 from which the sulfur oxides have been removed by the wet flue gas desulfurization device 5 is introduced into the wet electrostatic precipitator 6, and the dust is removed by a dust collecting electrode (not shown). The cleaning water 13 is constantly sprayed from above onto the dust collecting electrode to which the dust has adhered, and the washed dust is discharged from the lower hopper 14 together with the cleaning water 13.

[0006]

In the conventional wet type electrostatic precipitator 6 shown in FIG. 4, since the cleaning water 13 is constantly sprayed on the dust collecting electrode, a large amount of clean water is consumed and the cleaning water 13 is collected. There was a problem that the spray (not shown) sprayed on the dust pole was clogged.

An object of the present invention is to solve the above problems and to provide a wet electrostatic precipitator capable of washing away dust adhering to the dust collecting electrode without using washing water. is there.

[0008]

The invention according to claim 1 relates to a wet electrostatic precipitator characterized in that the dust collecting electrode can be cooled by a circulating cooling medium, and the dust collecting electrode is cooled. Since it is cooled by the medium, the water contained in the exhaust gas condenses and adheres to the surface of the dust collecting electrode, and the condensed water adheres to the surface of the dust collecting electrode while flowing down along the surface of the dust collecting electrode. It will wash away any dust that is present.

The invention of claim 2 relates to the wet electrostatic precipitator according to claim 1, characterized in that a cooling medium passage is provided along the dust collecting electrode, and the dust collecting electrode is efficiently cooled,
The cooling medium can also be used repeatedly.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a cut-away example of an embodiment of a dust collecting electrode used in the wet electrostatic precipitator of the present invention. Two electrode plates 15 and 16 are opposed to each other and are parallel to each other. These two electrode plates 15 and 16 are liquid-tightly joined to each other on both sides by a connecting member 17 over the entire length, and a cooling medium passage 18 is formed between the electrode plates 15 and 16 to form a dust collecting electrode 19. There is.

As shown in FIG. 2, a large number of the dust collecting electrodes 19 are installed in the wet electrostatic precipitator 20, and the cooling medium passages 18 formed in the respective dust collecting electrodes 19 (see FIG. 1).
To a cooling medium circulation system 21 provided with cooling medium pipes 22 and 23, a cooling medium circulation pump 24, and a cooler 25, and cooling water cooled by the cooling machine 25 of the cooling medium circulation system 21. The medium 26 circulates in the dust collecting electrode 19 to cool the dust collecting electrode 19.

The wet electrostatic precipitator 20 is arranged on the downstream side of the wet flue gas desulfurizer 5 as in the conventional case, and the lower hopper 27 of the wet electrostatic precipitator 20 is connected to the lower part of the wet flue gas desulfurizer 5 by a pipe 28. There is.

Next, the operation of the device shown in FIG. 2 will be described.

Exhaust gas 1 introduced into the wet flue gas desulfurization apparatus 5
As in the conventional case, 2 comes into contact with the absorbing liquid 9 sprayed from the spray 11, and the absorbing liquid 9 absorbs the sulfur oxide.

The exhaust gas 12 from which the sulfur oxides have been removed by the wet flue gas desulfurization device 5 is introduced into the wet electrostatic precipitator 20, and after the dust is removed by the dust collector 19, the reheater 7 on the downstream side (FIG. 3). ).

The exhaust gas 12 introduced into the wet electrostatic precipitator 20 from the above-mentioned wet flue gas desulfurization device 5 has a temperature of about 50 ° C. and is in a substantially saturated state.
Is the dust collecting electrode 1 that is cooled by the circulation of the cooling medium 26.
The water contained in the exhaust gas 12 is condensed and adheres to the surface of the dust collecting electrode 19 together with the dust.

When the amount of condensed water adhering to the surface of the dust collecting electrode 19 increases, it flows downward along the surface of the dust collecting electrode 19, at which time the dust adhering to the surface of the dust collecting electrode 19 is washed away. And the dust is dropped onto the lower hopper 27 of the wet electrostatic precipitator 20.

The water containing dust dropped in the lower hopper 27 of the wet electrostatic precipitator 20 is returned to the lower part of the wet flue gas desulfurization apparatus 5 through the pipe 28.

Although not shown, the wet flue gas desulfurization apparatus 5 is connected to a system for extracting the absorbent 9 in contact with the exhaust gas 12 to recover gypsum and a system for replenishing the absorbent slurry. The water containing dust returned from the lower hopper 27 of the wet electrostatic precipitator 20 to the lower part of the wet flue gas desulfurization device 5 is extracted together with the absorbing liquid 9 by the system for extracting the absorbing liquid 9.

The wet electrostatic precipitator of the present invention is not limited to the above-described illustrated examples, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0022]

As described above, according to the first aspect of the present invention, since the dust collecting electrode is cooled by the cooling medium, the water contained in the exhaust gas condenses and the dust collecting electrode has a surface. It adheres and the condensed water flows down along the surface of the dust collecting electrode to wash away the dust that has adhered to the surface of the dust collecting electrode, so it no longer consumes clean water and eliminates the problem of spray clogging. According to the second aspect of the invention, the dust collecting electrode can be efficiently cooled.

[Brief description of drawings]

FIG. 1 is a perspective view showing a cutaway example of an embodiment of a dust collecting electrode used in a wet electrostatic precipitator of the present invention.

FIG. 2 is a schematic diagram of an embodiment in which the wet electrostatic precipitator of the present invention is combined with a wet flue gas desulfurization apparatus.

FIG. 3 is a schematic diagram showing an example of an exhaust gas treatment device.

FIG. 4 is a detailed view of a portion IV in FIG.

[Explanation of symbols]

18 Cooling medium passage 19 Dust collecting pole 26 Cooling medium

Claims (2)

[Claims] 1. A wet electrostatic precipitator characterized in that the dust collecting electrode can be cooled by a circulating cooling medium. 2. The wet electrostatic precipitator according to claim 1, wherein a cooling medium passage is provided along the dust collecting electrode.