JPH05104027A - Operation of electric precipitator - Google Patents

Abstract

PURPOSE:To stably keep dust collecting efficiency constant in the optimum value even when the electric resistivity of dust changes in the operation of an electric precipitation. CONSTITUTION:In order to hold a dust collecting efficiency to the optimum value, the optimum power P is kept constant even when the electric resistivity of dust to be supplied to a discharge electrode 20 changes. That is, the voltage V applied to the discharge electrode 20 from a high voltage DC power supply device 24 and the current I flowing at this time are continuously detected by a voltage detector 28 and a current detector 30, and a multiplier 36 is controlled by a setting device 38 so that the product of the detected voltage V and current I, that is, the power P becomes constant in the optimum value and the power P is supplied to the discharge electrode 20. By this constitution, dust collecting efficiency eta can 6 stably be kept constant in the optimum value even when the electric resistivity of dust changes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an electrostatic precipitator, and more particularly to an electrostatic precipitator for treating industrial exhaust gas such as boiler exhaust gas and refuse incinerator exhaust gas, which is supplied to its discharge electrode. The present invention relates to a method of operating an electric dust collector that controls electric power.

[0002]

2. Description of the Related Art Conventionally, the electric power supplied to the discharge electrode of an electrostatic precipitator is controlled by a so-called constant current control system in which a current I flowing when a high voltage is applied to the discharge electrode is kept constant. is doing.

[0003]

However, in the conventional operation method of the electrostatic precipitator, the current I flowing when a high voltage is applied to the discharge electrode is kept constant, so that the dust layer is collected at the dust collecting electrode. The resistance between the discharge electrode and the dust collecting electrode is changed as a result of the formation of V and the voltage V applied to the discharge electrode is changed. That is, when the electric resistivity of dust is low, the voltage V decreases with time as shown by the curve A in FIG. 4, and when the electric resistivity of dust is high, it increases with time as shown by the curve B. .

On the other hand, the dust collection efficiency η of the electrostatic precipitator depends on the electric power P which is the product of the voltage V and the current I flowing at this time, and the electric power P is large under the condition that sparks or the like do not occur. Since the dust collection efficiency η tends to increase, the dust collection efficiency η decreases when the electric resistivity of the dust is low and the voltage V decreases. Further, when the electric resistivity of dust is high, the voltage V rises, so that sparks are generated in the space between the discharge electrode and the dust collecting electrode, and the dust collecting efficiency η is lowered.

The present invention has been made in view of the above circumstances, and it is possible to maintain the dust collection efficiency at an optimum value constant and stable even if the electric resistivity of dust changes. An object is to provide a method of operating a dust device.

[0006]

In order to achieve the above object, the present invention continuously detects the voltage applied from the high voltage DC power supply device to the discharge electrode and the current flowing at this time, and detects the detected voltage. It is characterized in that a constant electric power is supplied to the discharge electrode by controlling the product of the electric current and the electric current to be constant.

[0007]

According to the present invention, in order to maintain the dust collection efficiency at the optimum value, the optimum power is kept constant and supplied to the discharge electrode even if the electric resistivity of the dust changes. That is, the voltage applied from the high-voltage DC power supply device to the discharge electrode and the current flowing at this time are continuously detected, and the product of the detected voltage and current, that is, the electric power becomes constant at an optimum value. Control is performed to supply this electric power to the discharge electrode. As a result, even if the electric resistivity of dust changes, the dust collection efficiency can be kept constant at an optimum value and stably.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the method for operating an electrostatic precipitator according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an embodiment of an electrostatic precipitator 10 operated by the method of operating an electrostatic precipitator according to the present invention. The electrostatic precipitator 10 has an exhaust gas inlet 12 on the left side of the drawing and a right side of the drawing. An exhaust gas outlet 14 is formed in the exhaust gas, and a dust collection chamber 16 is provided between the inlet 12 and the outlet 14.

A plurality of dust collecting electrodes 18, 1 are provided in the dust collecting chamber 16.
.. are arranged at predetermined intervals in the depth direction in the drawing, and discharge electrodes 20, 20 ... Are arranged between the dust collecting electrodes 18, 18. Each of the discharge electrodes 20, 20 ... Is connected to a high voltage DC power supply device 24 via a cable 22. A charging device 26 shown in FIG. 2 is internally provided in the high-voltage DC power supply device 24, and a corona discharge is generated from each of the discharge electrodes 20, 20 ... By a high voltage applied (output) from the charging device 26. As a result, the dust in the exhaust gas introduced into the dust collecting chamber 16 from the inlet 12 is charged by the corona discharge and adheres to the dust collecting electrodes 18, 18.

As shown in FIG. 2, the charging device 26 comprises a voltage detector 28, a current detector 30 and the like. The voltage detector 28 continuously takes in and detects the voltage V applied to the discharge electrode 20. In addition, the current detector 30 can continuously take in and detect the current flowing at this time. The voltage detector 28 and the current detector 30 are connected to a multiplier 36 via smoothing filters 32 and 34, respectively. The multiplier 36 receives the voltage V from the voltage detector 28 and the current detector 30 input via the smoothing filters 32 and 34.
And the current I, that is, the power P is controlled by the setter 38 so as to be the optimum power P stored in advance in the setter 38. Controlled power P is supplied to the discharge electrode 20. The optimum power P is power for maintaining the dust collection efficiency η at an optimum value.

Next, the charging device 26 configured as described above.
The action of will be described. When a dust layer is formed on the dust collecting electrode 18 by the corona discharge generated from the discharge electrode 20,
The voltage V applied to the discharge electrode 20 and the current I flowing at this time change over time due to a voltage drop in the dust layer or a narrow distance between the discharge electrode 20 and the dust collecting electrode 18. The changed voltage V and current I are used as the voltage detector 2 of the charging device 26.
8. The voltage V and the current I are continuously detected by the voltage detector 28 and the current detector 30, respectively. Next, the detected voltage V and current I are output to the multiplier 36 via the smoothing filters 32 and 34, respectively. Calculated. Then, the current I is controlled to increase or decrease by the setter 38 so that the calculated power value becomes the optimum power P stored in the setter 38,
Then, the controlled electric power P is supplied to the discharge electrode 20.

As described above, in the present embodiment, the constant electric power P is supplied to the discharge electrode 20, so that the dust collection efficiency η is optimal even if the electric resistivity of the dust changes and the voltage V changes. The value can be kept constant and stable. Next, the operation of the charging device 26 will be described with a specific example. FIG. 3 shows changes with time in voltage V, current I, electric power P, and dust collection efficiency η when dust having a low electric resistivity of 10 ⁸ Ω · cm was collected.

According to FIG. 3, the voltage V decreases with time because it collects dust having a low electric resistivity, so that the current I is controlled to increase with time. As a result, a constant electric power P can be supplied, so that the dust collection efficiency η can be maintained constant at an optimum value. on the other hand,
When collecting dust having a high electric resistivity, the voltage V increases with time, so the current I is controlled to decrease with time. As a result, a constant electric power P can be supplied even if the electric resistivity of the dust changes, so that the dust collection efficiency η can be kept constant at an optimum value and stably.

[0014]

As described above, according to the operating method of the electrostatic precipitator according to the present invention, the voltage applied to the discharge electrode from the high voltage DC power supply and the current flowing at this time are continuously detected, Since the product of the detected voltage and current, that is, the electric power is controlled to be constant at an optimum value and the electric power P is supplied to the discharge electrode, the dust collection is performed even if the electric resistivity of the dust changes. The efficiency η can be kept constant at an optimum value and stably.

[Brief description of drawings]

FIG. 1 is an explanatory view of an electrostatic precipitator operated by an operating method of an electrostatic precipitator according to the present invention.

FIG. 2 is a block diagram of a charging device applied to a method of operating an electrostatic precipitator according to the present invention.

FIG. 3 is an explanatory diagram showing the dust collection efficiency of the electric dust collector operated by the operation method of the electric dust collector according to the present invention.

FIG. 4 is an explanatory diagram showing a change in voltage when operated by a conventional operation method of an electrostatic precipitator.

[Explanation of symbols]

 10 ... Electrostatic precipitator 18 ... Dust collector 20 ... Discharge electrode 24 ... High voltage DC power supply 26 ... Charging device 28 ... Voltage detector 30 ... Current detector 32 ... Smoothing filter 34 ... Multiplier 36 ... Setting device

Claims (1)

[Claims] 1. A voltage applied to a discharge electrode from a high-voltage DC power supply and a current flowing at this time are continuously detected, and the product of the detected voltage and current is controlled to be constant,
A method for operating an electrostatic precipitator, characterized in that a constant power is supplied to the discharge electrode.