JP3531707B2 - Operating method of electric dust collector - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to an electric current ChiriSo relates to luck <br/> rolling method location, especially in Tsuchida the dust collecting electrode and the discharge electrode shake off combustion ash electrostatic ChiriSo location Regarding driving method.

[0002]

2. Description of the Related Art Combustion ash contained in combustion gas discharged from a boiler or the like using heavy oil, heavy oil, or oil sand as fuel is usually collected by an electric dust collector. The discharge electrode and the dust collecting electrode of the electrostatic precipitator are hammered periodically by a hammer device, and most of the combustion ash adhering to the surface of the discharge electrode and the dust collecting electrode is peeled and removed.

[0003]

By the way, the operation of the boiler is stopped at the time of surplus power, periodic inspection, etc., and the outside air flows into the electrostatic precipitator. In such a case, a small amount of dust remaining on the discharge electrode and the dust collecting electrode is affected by the relative humidity of the atmosphere, and the amount of moisture absorption is small under the conditions of low relative humidity such as in winter, but at night in summer or during the rainy season. When the relative humidity is high, the amount of moisture absorption increases, and some of the dust dissolves in the absorbed water.

[0004] The absorbed dust recrystallizes a substance in which water is dissolved when the temperature is raised and dried when the boiler is restarted, and the adhesion to the discharge electrode and the dust collecting electrode becomes stronger. Therefore, when the number of times the boiler is stopped and restarted increases, the discharge electrode and the dust collecting electrode gradually increase in size, and in particular, when the discharge electrode increases in size, there is a problem that proper discharge cannot be performed.

[0005] The present invention has been made in view of such circumstances, operation of the electrostatic ChiriSo location that can improve the peelability of the dust adhering to the discharge electrode and the dust collection electrode during hammering The purpose is to provide a method.

[0006]

In order to achieve the above-mentioned object, the present invention discharges between a discharge electrode and a dust collecting electrode provided in a dust collecting chamber of an electrostatic precipitator to discharge the dust in the dust collecting chamber. In the operating method of the electrostatic precipitator, which collects dust in the dust-containing gas supplied to the device and removes the collected dust adhered to the discharge electrode and the dust collecting electrode by hammering, the boiler is stopped. It is characterized in that the hammering is performed while maintaining the inside of the dust collection chamber at a predetermined relative humidity or higher during the period from the start to the start.

[0007]

According to the present invention, by keeping the relative humidity in the dust collection chamber at a predetermined value or more, the combustion ash attached to the dust collection electrode and the discharge electrode absorbs moisture and the apparent mass increases. Therefore, since the peelability is improved when hammering the dust collecting electrode and the discharge electrode, the attached dust can be reliably removed. Further, according to the present invention, the relative humidity in the dust collection chamber is detected by the relative humidity detection device and compared with a predetermined relative humidity. If the detected value is less than the predetermined relative humidity,
A humidifier humidifies the dust collection chamber to a predetermined relative humidity or higher.

[0009]

DETAILED DESCRIPTION OF THE INVENTION will be described in detail preferred embodiments of the electrostatic ChiriSo location method of operating according to the present invention with reference to the accompanying drawings. FIG. 1 is an example in which the operation method of an electrostatic precipitator according to the present invention is applied to a dust removal flow of combustion ash (hereinafter referred to as dust) in combustion gas generated from a boiler.

As shown in FIG. 1, the gas containing combustion ash generated from the boiler 10 is first denitrified by a denitration device 12 to remove nitrogen oxides from the gas. Next, after passing through the air heater 14, ammonia gas is injected to neutralize sulfur trioxide in the gas and generate ammonium sulfate. The generated ammonium sulfate is supplied into the electrostatic precipitator 16 along with the gas flow along with the combustion ash.

The gas taken into the electrostatic precipitator 16 passes between the discharge electrode 20 and the dust collecting electrode 22. A DC voltage is applied between the discharge electrode 20 and the dust collecting electrode 22, and corona discharge is generated. Due to the corona discharge, the combustion ash in the gas is charged and adhered and collected on the dust collecting electrode 22. In this collecting operation, dust also adheres to the discharge electrode 20. The clean gas from which the combustion ash has been removed has the sulfur oxides finally removed by the desulfurization device 24, and is released from the chimney 26 to the atmosphere.

On the other hand, the dust adhering to the discharge electrode 20 and the dust collecting electrode 22 is separated from the dust collecting electrode 22 by a hammering operation with a hammer hammer 44, and the dust is attached to a hopper 28 provided under the electric dust collector 16. To fall. The combustion ash that has fallen and accumulated in the hopper 28 is extracted via the rotary valve 30. The extracted combustion ash is transported to the ash bin 34 by the screw conveyor 32.

A relative humidity measuring device 46 is provided outside the electrostatic precipitator 16 via a sampling pipe 45 to monitor the relative humidity in the electrostatic precipitator 16. Also,
A predetermined set value of relative humidity (for example, 50%) is preset in the relative humidity measuring device 46, and the relative humidity in the dust collection chamber is compared with the set value. The relative humidity measuring device 46 uses the humidifier 50 via the signal cable 48.
The humidifier 50 is connected to the inlet flue of the electrostatic precipitator 16 via a pipe 52. As a result, when the measured value of the relative humidity measuring device 46 is less than the set value, the humidifier 50 operates and the inside of the electrostatic precipitator 16 can be humidified.

Next, an operation method of the electrostatic precipitator constructed as described above will be described with an example of hammering when the boiler is stopped. When the boiler is stopped, the outside air flows into the electrostatic precipitator 16, and the temperature and humidity inside the electrostatic precipitator 16 eventually become the same as the outside air. The humidity in the electrostatic precipitator 16 is monitored by the relative humidity measuring device 46 via the sampling pipe 45. When the measured value is less than or equal to a predetermined set value, a signal is input from the relative humidity measuring device 46 to the humidifier 50 via the signal cable 48. The humidifier 50 humidifies the inside of the electrostatic precipitator 16 via the pipe 52 in response to the signal and raises the relative humidity to a set value.

When the relative humidity rises to the set value, the relative humidity is maintained at the set value and left for a predetermined time. After a lapse of a predetermined time (for example, 6 hours), with a DC power source 42 applying a DC voltage between the dust collecting electrode 22 and the discharge electrode 20, a hammer hammer 44 is used to discharge the discharge electrode 20 and the dust collecting electrode 22.
Hammer. By raising the relative humidity to the set value, the dust absorbs moisture, the apparent mass increases, and the peeling property improves. As a result, the dust attached to the discharge electrode 20 and the dust collecting electrode 22 can be reliably removed.

In the present embodiment, the combustion ash in the combustion gas generated from the boiler 10 has been described as dust.
The dust is not limited to this.

[0017]

EXAMPLES Next, an example of operation how the above electrostatic precipitator. FIG. 2 is a diagram showing the relationship between the relative humidity in the dust collection chamber and the amount of dust separation. Leave it for 6 hours,
The amount of dust peeling when the discharge electrode was hammered without applying a voltage to the discharge electrode was measured. As a result, the amount of dust removal is
At a relative humidity of 25%, it was as low as about 3 g, but it increased sharply at a relative humidity of about 40%, and at about 50% or more, it was almost constant at about 18 g. Therefore, it is understood that the set humidity is preferably 50%.

FIG. 3 is a view showing the moisture absorption rate of dust with time by changing the relative humidity. The moisture absorption rate is a percentage of the moisture absorption rate with respect to the weight of combustion ash. The temperature and humidity were kept constant using a thermo-hygrostat. As a result, the moisture absorption rate gradually increases, and after 6 hours or more, it becomes almost constant at 20% at 30% relative humidity, 50% at 40% relative humidity, and 70% at 60% relative humidity. Therefore, it is understood that the standing time is preferably 6 hours or more.

FIG. 4 is a graph showing the relationship between the applied voltage applied to the discharge electrode during hammering and the amount of dust peeled from the discharge electrode. The relative humidity in the dust collection chamber was 50%, and the standing time was 6 hours. As a result, the amount of dust peeled off is about 18 g when the applied voltage is 0 kV and 10 kV, but is 20 kV.
In the case of 30kV or more, it is about 60g.
Is almost constant at. For this reason, hammering is 50% relative humidity.
Leave for 6 hours or more, 20kV or more, or 30k
When the applied voltage is V or more, the peelability of dust is significantly improved.

[0020]

As described in the foregoing, according to the electrostatic precipitator <br/> equipment operating method of the present invention, by performing hammering keeping the dust collection chamber above a predetermined relative humidity, current The combustion ash adhering to the dust electrode and the discharge electrode absorbs moisture and has a large apparent mass, so that when the hammering of the dust collection electrode and the discharge electrode is performed, the dust peelability is improved. Therefore, the dust adhering to the discharge electrode and the dust collecting electrode can be reliably removed.

[Brief description of drawings]

FIG. 1 is a diagram showing a dust removal flow using an operation method of an electrostatic precipitator of the present invention.

FIG. 2 is a diagram showing the relationship between the relative humidity in the dust collection chamber and the amount of dust separation.

FIG. 3 is a diagram showing the moisture absorption rate of dust over time by changing the relative humidity.

FIG. 4 is a diagram showing the relationship between the applied voltage applied to the discharge electrode at the time of hammering and the amount of dust separated from the discharge electrode.

[Explanation of symbols]

10 ... Boiler 16 ... Electrostatic precipitator 20 ... Discharge electrode 22 ... Dust collector 42 ... DC power supply 44 ... Hammer hammer 46. Relative humidity measuring device 50 ... Humidifier

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-68193 (JP, A) JP-A-62-7458 (JP, A) JP-A-1-266866 (JP, A) JP-A-62- 45362 (JP, A) JP-A-61-111154 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B03C 3/00-3/88

Claims (3)

(57) [Claims] 1. An electric dust collector is provided with a discharge electrode provided in a dust collecting chamber and a dust collecting electrode to discharge the dust in a dust-containing gas supplied into the dust collecting chamber, and In a method of operating an electrostatic precipitator in which dust collected and adhered to the discharge electrode and the dust collecting electrode is removed by hammering, in a period from when the boiler is stopped until when the boiler is started, a predetermined relative amount is set in the dust collection chamber. A method for operating an electrostatic precipitator, characterized in that the hammering is performed while maintaining the humidity at or above. 2. The relative humidity in the dust collection chamber is detected, and if the detected value is less than the predetermined relative humidity, the dust collection chamber is humidified to raise the dust collection chamber to a predetermined relative humidity or higher. The method for operating the electrostatic precipitator according to claim 1, wherein the operation is performed. 3. The method of operating an electrostatic precipitator according to claim 1, wherein the predetermined relative humidity is 50%.