JPH02253868A - Automatic hammering control method for electrostatic precipitator - Google Patents

Abstract

PURPOSE:To prevent the frequent generation of abnormal discharges by inputting the voltage signal from a voltage detector to a thyristor controller, making discrimination that the discharge characteristics of the electrostatic precipitator turn to the frequency generation of spark discharges by a microcomputer unit and automatically changing the hammering periods of dust precipitating electrodes. CONSTITUTION:The controller 20 having the thyristor 22 controls a low-voltage AC power source with the charge voltage and current value of the electrostatic precipitator 26 as the feedback signals in a DC high-voltage power source device which supplies DC high-voltage to the electrostatic precipitator 26. Of the above-mentioned feedback signals, the voltage signal obtd. from the voltage detector 28 is inputted to the thyristor controller 20 which in turn detects the shaft drop condition of the voltage value as the spark discharge. The hammering period of the dust precipitating electrodes of the precipitator 26 is accelerated for the specified period of time at the point of the time when the number of detection times per the prescribed time attains the value above the preset limit value. As a result, the degradation in the performance of the electrostatic precipitator and the frequency generation of the abnormal discharge, such as glow discharge, is automatically suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic impact control method for electrodes applied to a thyristor control device in a DC high-voltage power supply device for a electrostatic precipitator (GP).

[Conventional technology]

in general! 9. The i8P is equipped with a power supply device that generates a DC high voltage, and the current from the power supply device generates 9. The dust introduced into the EP is electrically charged, and the charged dust is attached to a dust collection electrode using a Coulomb force generated by a high electric field, thereby separating and removing the dust from the gas. In such an IP power supply device.

As shown in FIG. 6, the alternating current power supply AC is regulated by controlling the phase of the thyristor using a phase angle control signal from the thyristor control device 1. It is supplied to EP6 through DC reactor 5. In this case, the current detector 1 and the voltage detector 8 each detect the current and voltage supplied to the EP and feed it back to the thyristor control device.

Here, in order to prevent the IP performance from deteriorating due to the occurrence of spark discharge inside the EP, the control device is equipped with a spark frequency control means. This control means is activated in the event that a situation arises. On the other hand, IP dust collection pole, hammering motor 12
is operated at a set cycle by a separately provided control device 11tlC.

[Problem to be solved by the invention]

Conventionally, since the configuration of the control device is as described above,
When the discharge characteristics of the EP are such that spark discharge occurs (1) the operation of the IP becomes unstable.

(2) Since the voltage decreases every time a spark discharge occurs,
EP performance deteriorates significantly.

Phenomena such as these have occurred and have become a problem in IP operation.

This is because the EP charge control device, that is, the thyristor control device 1 and the dust collection pole impact control device 1, are each installed independently, and the charging characteristics and pole impact control are controlled artificially. In actual EP operation, it is impossible to respond to the ever-changing discharge characteristics because setting the optimum state requires extensive skill and adjustment time. This is because.

[Means and effects for solving the problem] The present invention has been made to solve the above-mentioned problems, and the EP discharge characteristics that cause spark discharge are such that the dust collection by appropriate dust collection pole impact is improved. Focusing on the fact that removing dust from the top of the electrode plate improves the performance, we incorporated a dust collection pole impact control function into the thyristor control device and integrated the control device. This provides a method for automatically performing a series of controls such as correcting and restoring the batting cycle.

For the spark frequency control function of the thyristor control device, which is the charge control device of the EP, there is a function that counts the time during which the number of spark discharges in one minute within the EP is within the detection frequency control value range, and this count time and Compare the predetermined times and
We have added a function to detect an abnormality in the discharge characteristics of the dust collector and a function to change the dust collection hammering cycle based on the signals from these functions, and automatically perform the following series of controls.
Operate while improving the discharge characteristics of EP.

1st: While the IP is operating, it counts the time during which the number of spark discharges per minute is within the detection frequency limit range, and at the same time outputs a fixed cycle dust collection pole hammering signal to the thyristor control device. and perform dust collection hammering control.

Second: When the time during which the number of spark discharge occurrences per minute is within the detection number limit range exceeds a predetermined time, the thyristor control device performs the following control.

Initialize the count time Shorten the period of the dust collection hammer striking signal by a certain value, or
Continuously, for a predetermined period of time, the removal of excess accumulated dust on the dust collecting electrode plate is facilitated.

(3) After a predetermined period of time has elapsed, the dust collector hammering signal that has become shortened or continuous is returned to its initial value, and
As per the above, one hour is counted according to the spark discharge occurrence situation. Thereafter, repeat the above 1st and 2nd operations.

3rd = In the above 2rd step, if the time during which the number of spark discharge occurrences per minute is within the detection frequency limit range is within a predetermined time, after this time has elapsed, the count value is initialized. After doing so, the time count is restarted depending on the above spark discharge occurrence situation. , (In this third step, the cycle of the dust collection pole impact signal is not changed).

〔Example〕

An embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing the configuration of an embodiment of an apparatus used to carry out the method of the present invention.
22 digit Nyristor, 23 is a high voltage transformer, 24 is a rectifier,
25 is a DC reactor, 26 is EP, a is a discharge electrode, p is a dust collection electrode, 27 is a current detector, 28 is a voltage detector,
20 is a thyristor control device, 21 is a microcomputer unit, and 32 is a dust collection pole impact motor.

In the device with this dangerous configuration, the voltage detector 28
The running voltage signal detected by the
The signal is input to the microcomputer unit 21 built into the 0. The microcomputer unit 21 has a configuration as shown in FIG.
It is digitized through the digital converter 42 and stored in the memory (RA).
At the same time, the CPU 4s
In addition to conventional spark detection control that utilizes sudden changes in voltage data during spark discharge, the following control according to the present invention is also performed. In other words, under conditions where spark discharge occurs during EP operation, the time TH during which the number of spark discharge occurrences n of the machine per minute is within the detection frequency limit range (no±α) as shown in period , the CPU 43 counts and at the same time constant period TN.

Output the dust collection pole impact signal from I10 port 45,
Controls the operation of the dust collection pole impact motor.

Here, the time T is the time during which the number of spark discharge occurrences of the machine per minute is within the detection frequency limit value range. However, when the predetermined time TB has elapsed (0 point), the count time memo IJ (
TH) is initialized (TH=0), and the period of the dust collection pole striking signal ``IO'' is set by the CPU 21 as Tl!,
1, outputs a dust collection pole impact signal with a period of T□ from the I10 port 45 for a predetermined time Tc, and increases the operating time of the dust collection pole impact motor 32. Removal of excess deposited dust on the board is facilitated. (In addition,
During this predetermined time Tc, counting of the time TH during which the number of spark discharge occurrences of the machine per minute falls within the detection frequency limit value range is interrupted once.
Regarding t, the off time is set to 10'', and the dust collecting pole hammering motor may be operated continuously.) After the predetermined time Tc has elapsed, the dust collecting pole striking cycle, which was T□, is changed to CPU 4. s, the initial value T3° is returned again, the dust collection pole impact motor 32 is operated, and the time count TH is restarted depending on the spark discharge generation status of EP.

FIG. 4 shows the operation of this control when shifting from spark frequency control to constant voltage limit control, as an example when the IP discharge characteristics change. In Figure 4, the time T during which the number of spark discharge occurrences in one minute is within the detection frequency limit range.
If F1 does not exceed the predetermined time tB, after the number of spark discharges of the machine in one minute falls outside the detection number limit value range,
(0 point), the time count TN is initialized (TH=0), and thereafter, the time count TH is restarted depending on the spark discharge generation situation. Therefore, in this case, the period of the dust collection pole impact signal is not changed, and the initial set value TK
The dust collection hammering motor is operated with the state set to O.

FIG. 5 shows a flowchart of the operations shown in FIGS. 3 and 4 above. Note that the flow chart diagram shown in FIG. 5 is a memo in the microcomputer unit 21! j (RO
M44) K is stored.

〔Effect of the invention〕

According to the method of the present invention, as shown above, the voltage signal obtained from the voltage detector 28 is input to the thyristor control device, and the microcomputer unit 21 adjusts the discharge characteristics of the EP such that spark discharge occurs frequently. The following effects can be expected because the dust collection hammering cycle can be automatically changed.

(1) As for the discharge characteristics of the EP, in case spark discharge occurs frequently, it is possible to automatically suppress the performance deterioration of the EP and the occurrence of abnormal discharge such as glow discharge.

(2) In EP where discharge characteristics change, operator skill and adjustment time are not required.

(3) Changes in the discharge characteristics of It:P can be reduced, and the operation of the EP can be made more stable than before.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a system using a control method according to an embodiment of the present invention, and FIG. 2 is a block diagram of a device used for the control. FIG. 3 shows automatic control in which the dust collection pole striking period changes due to an abnormality in discharge characteristics. FIG. 4 also shows control that does not change. Figure It5 is a flowchart of the control program for the microcomputer unit according to the present invention. FIG. 6 is a block diagram showing a conventional control method. 4--Isolated amplifier, 42--A converter, 43-
...CPU, 44...ROM (stores control program), 45...Digital signal input/output port, 46
...Interface for operation knob (=operation control), 47...Operation armpit (=operation control), 48...
RAM (stores variable data, such as count time TH, etc.) 49 - D/A converter.

Claims (1)

[Claims] In a DC high-voltage power supply device that supplies a DC high voltage to an electrostatic precipitator (EP), a control device having a thyristor that adjusts a low-voltage AC power supply using the charging voltage and current value of the EP as a feedback signal, the feedback signal A sudden drop in the voltage value is detected and detected as a spark discharge, and when the number of detections per predetermined time exceeds a preset limit value, the EP dust collection pole striking cycle is set to a constant value. An automatic impact control method for EP characterized by accelerating time.