JPH02203946A - Operation of electric precipitator - Google Patents

Abstract

PURPOSE:To perform the operation of high reliability by a method wherein the operation of energy saving control is made possible to continue by one of two soot densitometers even when the other soot densitometer is changed with the elapse of time or breaks down and difference between the two soot concn. signals is checked. CONSTITUTION:The changes of the soot concns. with the elapse of time of the first and second soot densitometers 2-1, 2-2 and the difference between the soot concn. signals of the densitometers 2-1, 2-2 are investigated by a load control apparatus 4'. The control apparatus 4' uses the output of the densitometer 2-1 or 2-2 when the above mentioned changes with the elapse of time are a predetermined value or less and the above mentioned difference is predetermined value difference or less. When the above mentioned changes with the elapse of time exceed the predetermined value, the output of the soot densitometer not exceeding the predetermined value is used. Further, when the above mentioned changes with the elapse of time are the predetermined value or less and the above mentioned difference exceeds the predetermined value difference, the output of the soot densitometer larger in the soot concn. signal is used. As a result, operation of high reliability can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of operating an electrostatic precipitator applied to energy saving control.

[Prior Art] FIG. 3 shows a schematic configuration of a conventional soot and dust concentration control system for an electrostatic precipitator. A dust concentration meter 2 is installed at the outlet of the electrostatic precipitator 1, and this is used to detect the amount of dust in the exhaust gas at the outlet of the electrostatic precipitator, and the charge control device 4 detects soot and dust that is correlated with the amount of dust. By foot-banking the concentration signal 3, the charge control device 4 controls the charge amount of the DC high voltage of the DC high voltage power supply device 5 or the charge rate of intermittent charging so that the amount of dust at the outlet of the electrostatic precipitator 1 becomes a predetermined value. The voltage and current are automatically set by the DC high voltage power supply device 5 and the discharge electrode 6 is supplied with voltage and current based on the set values. Here, the soot and dust concentration meter 2 is purged periodically or continuously to maintain a clean state at the initial stage of operation. In addition, in order to improve the reliability of the concentration signal, an alarm signal No. 7 is input to the charge control device 4 in the event of a failure. The charge control device 4 monitors the change over time and failure of the dust concentration meter 2.

[Problem to be solved by the invention]

If the conventional system described above is used for a long period of time, there is a high possibility that abnormalities such as changes over time will occur in the dust concentration meter. The output signal (soot concentration signal) of the soot concentration meter where an abnormality has occurred cannot be said to be accurate, and there is a concern that the control using it may become abnormal, so the control has to be interrupted. There wasn't.

[Means to solve the problem] The present invention takes the following measures to solve the above problems.

That is, the method for operating the electrostatic precipitator includes an electrostatic precipitator, a DC high voltage power supply device that charges the electrostatic precipitator with a DC high voltage, and a first method that measures the dust concentration at the outlet of the electrostatic precipitator. and a second particulate concentration meter, which processes the particulate concentration signal output from the same particulate concentration meter and supplies the DC high voltage power supply to the electrostatic precipitator, or In equipment equipped with a charge control device that sets and commands the charging rate of intermittent charging, the change over time of the soot and dust concentration signals of the first and second soot and dust concentration meters, and the soot and dust concentration signals of the first and second soot and dust concentration meters. The control device detects the difference in the concentration signal, and the charge control device detects the difference between the first and second soot and dust concentration meters when the change over time is less than a predetermined value and the difference is less than a predetermined value difference. When the above-mentioned change over time exceeds a predetermined value, use the output of the dust concentration meter that does not exceed the specified value.
When the above-mentioned change over time is less than a predetermined value and the above-mentioned difference exceeds a predetermined value difference, the output of the soot and dust concentration meter having a larger soot and dust concentration signal is used.

[Effect]

With the above means, the charge control device examines the change over time of the soot and dust concentration signals of the first and second soot and dust concentration meters and the difference between the soot and dust concentration signals of the first and second soot and dust concentration meters, and the charge control device When the above-mentioned change over time is below a predetermined value and the above-mentioned difference is below a predetermined value difference, the output of the first or second dust concentration meter is used, and when the above-mentioned change over time exceeds a predetermined value, the one that does not exceed When the change over time is less than a predetermined value and the difference exceeds a predetermined value difference, the electrostatic precipitator uses the output of the soot and dust concentration meter that has a larger soot and dust concentration signal. Operation is performed by setting and commanding the amount of charge of the DC high voltage supplied to the unit or the charge rate of intermittent charging.

In this way, highly reliable operation is achieved.

[Example] An example to which the method of the present invention is applied will be described with reference to FIGS. 1 and 2.

Note that the description of the portions described in the conventional example will be omitted to avoid redundancy, and the description will mainly focus on the portions related to the present invention.

In Figure 1, the first dust concentration meter (A) 2-1 of the light scattering type or light transmission type and the second dust concentration meter (1'1
) 2-2 are provided, and each particulate concentration signal 3-1
3-2 and alarm signal 74.7-2 to charge control device 4
’. Also, the signal 8 used for the display (not shown)
-L 8-2. A large difference signal 9 is input.

In the above configuration, the charge control device 4' reads each particulate concentration signal 3-1 and 3-2, constantly calculates the average value over a certain period of time, and stores it in memory. When starting energy saving control operation, use a predetermined method such as a dust concentration meter (
A) Alarm signal 7-1 of two dust concentration meters 2-12-2 while controlling using output signal 3-1 of 2-1.
7-2. Changes over time and both dust concentration signals 3-
Check the difference between L3-2.

If a failure or change over time occurs in the soot and dust concentration meter (A) 2-1, the soot and dust concentration meter (B) 2-
The energy saving control operation is continued using the second output signal, and the alarm signals of the two soot and dust concentration meters, changes over time, and the difference between the soot and dust concentration signals are checked. Dust concentration meter (B)
If a failure or a change over time occurs in 2-2, from then on, the energy saving control operation will be continued using the output signal of 2-1. Which soot and dust concentration meter output is used? υo used signal 8-1
．． ．． )l-2 is displayed on the display. If both soot and dust concentration meters break down or change over time, it is unavoidable that the energy-saving control operation will be interrupted.

In addition, when both soot concentration meters are normal, if the difference between the two soot concentration signals is greater than the allowable value α, an exaggerated signal 9 is output and displayed, and the higher soot concentration signal is used. Continue energy-saving control operation. Here, the allowable value α for the difference between the soot densitometers varies depending on the model of the soot densitometer used and the installation condition, but is determined by the following formula ( ]).

cy=(So X a +w) B---(1)
α: Allowable value of difference in soot concentration signal (mg/Nm”) S
o; Measuring range of the dust concentration meter used (mg/Nm
') a: Measurement error W; 71111 determined maximum difference during test run (mg/
Nm″) B: Tolerance Note that W is the value measured when the two dust concentration analyzers are in a normal state.

The flowchart of information processing for driving north is shown in Figure 2.

In this way, the electrostatic concentrator can be operated with high reliability.

(Effects of the invention) As detailed above, in the conventional energy-saving control operation method, only one soot and dust concentration meter was used, so if a failure or change over time occurs, the control will continue until it is repaired. However, according to the method of the present invention, even if one particulate densitometer changes or breaks down, the energy saving control operation can be interrupted by another particulate densitometer. The reliability of energy saving control can be improved by changing the difference between the two dust concentration signals.

[Brief explanation of the drawing]

The first circle is a block diagram of the first embodiment of the present invention, FIG. 2 is a flow diagram explaining the operation of the same embodiment, and FIG. 3 is a block diagram of the conventional method. ■---Electrostatic concentrator 2, 2-1, 2-2---Soot and dust concentration meter 33-13
-2--Dust concentration signal 4.4'--Charge control device 5--Direct current high voltage power supply device, 6--Discharge electrode 77-17
-2---Soot and dust concentration meter alarm signal 8-18-2---
- Use of soot and dust concentration meter Report 9 --- Large difference signal of soot and dust concentration signals

Claims (1)

[Claims] An electrostatic precipitator, a DC high voltage power supply device that charges the electrostatic precipitator with a DC high voltage, first and second dust concentration meters that measure the soot and dust concentration at the outlet of the electrostatic precipitator, and the same soot and dust a charge control device that processes the dust concentration signal output from the concentration meter and instructs the DC high voltage power supply device to set the amount of charge of the DC high voltage or the charge rate of intermittent charging to be supplied to the electrostatic precipitator; In the equipped equipment, the charge control device examines the change over time of the soot and dust concentration signals of the first and second soot and dust concentration meters and the difference between the soot and dust concentration signals of the first and second soot and dust concentration meters, and When the above-mentioned change over time is below a predetermined value and the above-mentioned difference is below a predetermined value difference, the charge control device controls the first or second
When the above change over time exceeds a predetermined value, the output from the other soot and dust concentration meter is used, and the above change over time is less than or equal to the predetermined value, and the above difference is the predetermined difference. 1. A method for operating an electrostatic precipitator, characterized in that when the concentration signal exceeds 1, the output of the soot and dust concentration meter having a larger soot and dust concentration signal is used.