JPH04310253A - Method for preventing scattering of dust in electric precipitator - Google Patents

Abstract

PURPOSE:To provide an electric precipitator capable of preventing the scattering of dust when dust is shaken off. CONSTITUTION:The supply amount of the air from an air seal supply apparatus (fan 68) at the time of the shaking-off of dust is limited to the quantity not opening dividing dampers 22, 30 by the atmospheric pressure in a dust collecting chamber (A-chamber).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for preventing dust scattering in an electrostatic precipitator, and in particular to an electrostatic precipitator that removes dust in the gas by passing dust gas discharged from combustion equipment such as a thermal power plant. This article relates to a method for preventing dust from scattering in a dust container.

0002

[Prior Art] Generally, dust gas discharged from combustion equipment such as thermal power plants cannot be discharged into the atmosphere in that state for pollution prevention reasons, so it is passed through an electrostatic precipitator to collect dust (
Dust) is discharged into the atmosphere at a concentration below the regulation value. Such an electrostatic precipitator has a plurality of dust collection chambers, and sectional dampers are installed on both sides of the gas inlet and outlet of these dust collection chambers to seal the dust collection chambers. When the sectional damper is released to introduce dust gas into the dust collection chamber, the dust gas is charged by corona discharge from a discharge electrode attached to the dust collection chamber and adheres to the dust collection electrode. Thereby, the dust concentration in the dust gas can be reduced, and the gas with the reduced dust concentration is released into the atmosphere from the gas outlet of the dust collection chamber.

By the way, if a large amount of dust adheres to the dust collecting electrode, the dust collection efficiency will decrease, so in order to prevent this problem, the dust collecting electrode is intermittently hammered with a hammering device. I try to shake off the dust that has adhered to it. Furthermore, the partition damper is closed to keep the dust collection chamber in a sealed state so that dust gas is not introduced into the dust collection chamber during hammering. Furthermore, air is supplied to the insulator chamber in which the insulator supporting the discharge electrode is provided, and this air is blown from the insulator chamber toward the dust collection chamber to form an air seal, so that the dust scattered during hammering is removed from the insulator. Prevents it from entering the room.

0004

[Problems to be Solved by the Invention] However, in conventional electrostatic precipitators, air is continuously blown out from the insulator chamber when dust is removed by a hammering device, so the air pressure inside the dust collection chamber increases during the dust removal time. It rises accordingly. When the amount of rise exceeds the pressing force of the divisional damper to seal the dust collection chamber, a gap is created between the gas inlet and outlet, and the air in the dust collection chamber is vigorously discharged from this gap. As a result, the falling dust is scattered in the dust collection chamber, resulting in a reduction in the dust collection rate.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for preventing dust scattering in an electrostatic precipitator, which can prevent dust scattering during dust removal.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of dust collection chambers which are divided into a plurality of parts and are provided with a dust collection electrode, a discharge electrode, and a hammering device, and a plurality of sectional dampers attached to both sides of each gas inlet and outlet of the dust collection chamber to seal each dust collection chamber; an insulator chamber provided with an insulator supporting the discharge electrode; an air seal supply device that blows air from the insulator chamber to the dust collection chamber to prevent dust in the dust chamber from entering the insulator chamber; In the method for preventing dust scattering in an electrostatic precipitator when dust adhering to the device is removed by the hammering device, the dividing damper controls the amount of air supplied from the air seal supply device when removing the dust from the dust collecting device. It is characterized by being limited to an amount that does not open due to indoor atmospheric pressure.

[0007]

According to the present invention, the amount of air supplied from the air seal supply device during dust removal is limited to an amount below which the divisional damper does not open due to the atmospheric pressure in the dust collection chamber. That is,
As a method for this, the air supply from the air seal supply device is stopped or reduced for a short time. This results in
Since the divisional damper can be prevented from opening due to an increase in the atmospheric pressure in the dust collection chamber, it is possible to prevent dust from scattering during dust removal.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for preventing dust scattering in an electrostatic precipitator according to the present invention will be explained in detail below with reference to the accompanying drawings. FIG. 1 shows an embodiment of an electrostatic precipitator to which the method for preventing dust scattering of an electrostatic precipitator according to the present invention is applied.

As shown in FIG. 1, a dust gas inlet 12 and an outlet 14 are formed on both sides of the electrostatic precipitator main body 10. Further, as shown in FIG. 2, the electrostatic precipitator main body 10 has a dust collection chamber divided into chambers A, B, C, and D by partition plates 16, 18, and 20 indicated by dotted lines in the figure. . Inlet side divisional dampers 22, 24, 26, and 28 are installed near the dust and gas inlets 12 of the rooms A to D, respectively.
In addition, outlet-side section dampers 30, 32, 34, and 36 are installed near the dust and gas outlet 14, respectively. These inlet-side section dampers 22 to 28 and outlet-side section dampers 30 to 36 are opened when introducing dust gas into chambers A to D, and closed when dust adhering to dust collection electrodes 40, which will be described later, are brushed off. individually controlled.

As shown by the dotted lines in FIG. 1, two pairs of discharge electrodes 38 and two pairs of dust collection electrodes 40 are provided in the A, B, C, and D chambers, respectively. The discharge electrode 38 is connected to the electrostatic precipitator main body 10
The insulators 42, 42, . Further, the discharge electrode 38 is connected to a DC high-voltage power source (not shown), and generates corona discharge by applying a DC high-voltage voltage from the DC high-voltage power source. The dust collection electrode 40 is disposed parallel to the discharge electrode 38 and at a predetermined interval, and dust in the dust gas charged by the corona discharge adheres to its surface.

Further, a pair of hammering devices 46, 46 are installed at positions where the dust collecting poles 40, 40 can be hammered, and the hammering devices 46, 46 hammer the dust collecting poles 40, 40. As a result, dust adhering to the surfaces of the dust collecting electrodes 40, 40 can be brushed off. The dust that has been brushed off falls due to its gravity, is temporarily stored in a hopper 48 provided at the bottom of the electrostatic precipitator main body 10, and is transferred to a discharge device 50.
, 50 to the outside of the electrostatic precipitator main body 10.

On the other hand, the above-mentioned insulator chambers 44, 44...
Ducts 52, 54, 56, 5 for each dust collection room from room A to room D
These ducts 52 to 58 are connected to a fan 68 via electromagnetic valves 60, 62, 64, and 66. Therefore, by operating the fan 68, the electromagnetic valve 6
0 to 66 are released, the outside air supplied by the fan 68 passes through the ducts 52 to 58, and each insulator chamber 44, 44...
supplied to The outside air supplied to each insulator chamber 44, 44... is blown out from inside each insulator chamber 44, 44... toward rooms A to D.

By the way, the electromagnetic valves 60 to 66 and the fan 68 are connected to a control device 70 via cables, respectively.
It is connected to the. This control device 70 controls the fan 68
The rotation speed of the electromagnetic valve 6 can be controlled.
The opening/closing amount from 0 to 66 can also be individually controlled. Next, a method for preventing dust scattering using the electrostatic precipitator configured as described above will be explained.

For example, the dust collecting electrode 4 installed in room A of the dust collecting room
When enough dust has adhered to the chamber 0, in order to brush off the dust, first close the inlet section damper 22 and the outlet section damper 30 of the A chamber to prevent dust gas from being introduced into the A chamber. Next, the aforementioned control device 70 operates the fan 68 and opens the electromagnetic valve 60 to supply outside air to the insulator chamber 4.
Air blows from 4, 44... toward room A, insulator chambers 44, 44
An air seal is formed between ... and chamber A. At the same time, the hammering device is operated to hammer the dust collecting electrode 40 and knock off the dust. As a result, the dust that has been brushed off is prevented from entering the insulator chambers 44, 44, . . . by the air seal, and falls due to the gravity of the dust.

Furthermore, when the amount of outside air from the insulator chambers 44, 44, . . .
When the closing pressure exceeds 0, the falling dust is blown out from the gap between the inlet-side section damper 22 and the outlet-side section damper 30 to the outside of the air in the A chamber, and the falling dust is scattered. Therefore, in order to eliminate this problem, the control device 70 limits the amount of insulator air sealing. Here, since the relationship between the amount of insulator air sealing and the amount of scattered dust is proportional as shown in FIG. 3, the amount of insulator air sealing is reduced to an extent that dust does not enter the insulator chamber 44. The means for this purpose is to use the control device 70 to stop the fan 68 for a short time or to reduce the opening degree of the electromagnetic valve 60. Thereby, it is possible to prevent dust from scattering from the gap between the inlet-side section damper 22 and the outlet-side section damper 30.

FIG. 4 shows the relationship between the dust collection efficiency and the charging time of the dust gas processing time.
The solid line shows the case where the electrostatic precipitator is stopped for a short time, and the broken line shows the case with the conventional electrostatic precipitator. As shown in FIG. 3, it was found that in this example, the dust collection efficiency could be improved by charging for a shorter time than when using a conventional electrostatic precipitator.

[0017]

As explained above, according to the method for preventing dust scattering in an electrostatic precipitator according to the present invention, the dividing damper controls the amount of air supplied from the air seal supply device during dust removal into the dust collection chamber. This prevents the sectional damper from opening due to the influence of the atmospheric pressure in the dust collection chamber, thereby preventing dust from scattering when dust is removed.

[Brief explanation of drawings]

[Figure 1] Side view showing an example of an electrostatic precipitator

[Figure 2] Top view showing an example of an electrostatic precipitator

[Figure 3] Explanatory diagram showing the relationship between the amount of insulator seal air and the amount of scattered dust

[Figure 4] Explanatory diagram showing the relationship between charging time and dust collection rate

[Explanation of symbols]

10...Electrostatic precipitator main body 22, 24, 26, 28...Inlet side division damper 30, 32
, 34, 36... Outlet side divisional damper 38... Discharge electrode 40... Dust collection electrode 60, 62, 64, 66... Solenoid valve 68... Fan 70... Control device

Claims (1)

[Claims] 1. A plurality of dust collection chambers that are divided into a plurality of sections and are provided with a dust collection electrode, a discharge electrode, and a hammering device, and a dust collection system in which each of the plurality of dust collection chambers is hermetically sealed. sectional dampers attached to both sides of each gas inlet and outlet of the chamber; an insulator chamber provided with an insulator that supports the discharge electrode; and an insulator chamber provided with an insulator that supports the discharge electrode, and a and an air seal supply device that blows air into a dust collection chamber, and after the dust collection chamber is sealed with the division damper, the dust adhering to the dust collection electrode is removed by the hammering device. The method for preventing scattering of dust in a container is characterized in that the amount of air supplied from the air seal supply device during dust removal is limited to an amount below which the divisional damper does not open due to the air pressure of the dust collection chamber. How to prevent dust from scattering in an electric precipitator.