JPH0326353A - Water washing and operating method for electrostatic precipitator - Google Patents

Abstract

PURPOSE:To make splash of dust and soot little by providing both a plurality of dust collection blocks and an air quantity changeable type fan in an air duct and equipping the dampers and the water scrubbers to the respective dust collection blocks. CONSTITUTION:Dust and soot introduced into the charging part units 3 are energized by corona discharge and introduced into an electric field formed by the dust collection part units 4 of the downstream thereof. Dust and soot are collected in the dust collection part units 4 by Coulomb's force. Air quantity is controlled by an air quantity changeable type fan 9 so that the passing air velocity of the dust collector main body 1 is regulated to value V preset by the ventilation state of an equipment to be made an object. Collected soot and dust are washed away by periodically closing the dampers 2 and interrupting the high-voltage power sources 6 and injecting spray water from the water scrubbers 5. Thereby drying operation can be performed at the rated maximum air velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a water washing operation method for an electrostatic precipitator for removing dust from the air.

Conventional technology 2 Generally, electrostatic precipitator equipment using a variable air volume blower used for tunnel ventilation etc. has an air volume that satisfies the ventilation capacity and air cleanliness required depending on the ventilation status of the target equipment. It is driven by. During the dust collection process, soot and dust accumulates on the charging section unit button inside the dust collector body and on the discharge wires and electrode plates of the dust collection section, but to prevent this from becoming excessive and causing abnormal discharge, soot and dust should be removed periodically. Equipped with a water cleaning device.

Figure 1 shows an example of this. 1 is a dust collector main body, which has dampers 2 and 2' on the inflow side k and the outflow side, and a charging section unit 3 and a dust collecting section unit 4 are housed inside. On the inflow side of the charging section unit 3 and the outflow side of the dust collecting section unit 4, a water washing device 6 is provided, which is monitored by a nozzle or the like (not shown). and charging unit 3,
A high voltage is applied to the dust collecting unit 4 from a high voltage power supply 6. A plurality of dust collecting blocks 8a to 8c are installed in the air passage 7 of the electrostatic precipitator main body 1.

Behind the dust collection blocks 8a to 8c, a variable air volume blower 9 equipped with a variable blade mechanism or a rotation speed control mechanism (not shown) is installed.

When the above structure is clicked, the soot dust that has flowed into the charging unit 3 is charged by corona discharge, enters the electric field formed in the downstream dust collecting unit 4, and is turned off by the coulomb. is collected by. The air volume of the variable air blower 9 is controlled so that the wind speed passing through the dust collector main body 1 becomes a value V set based on the ventilation status of the target equipment. The soot dust collected in this way is periodically closed by damper 2.
The water is washed away by turning off the high-voltage power source 6 and spraying water from the water washing device 6. FIG. 3 shows a cleaning time chart of a conventional electrostatic precipitator, and the cleaning process is performed sequentially for each dust collection block 8a to 8C. After washing with water, the charging section unit 3 and the dust collecting section unit 4 are wet with water and the insulation has deteriorated, so high voltage cannot be applied immediately. However, in order to recover the insulation as soon as possible from this state, The variable air volume blower 9 is controlled so that the wind speed passing through the electrostatic precipitator main body 1 is at the rated maximum wind speed from the end of cleaning of the dust collecting block 8a until a certain time t has elapsed after cleaning of all the dust collecting blocks 8a to 8c. Forced drying was performed.

Problems to be Solved by the Invention In general, in electrostatic precipitators, there is a phenomenon in which part of the soot and dust once attached to the dust collection unit 4 is re-dispersed by the passing wind. (amount of soot and dust attached to)
However, the amount of soot and dust re-scattered decreases when the wind speed passing through the electrostatic precipitator body 1 is slow, so it depends on the ventilation conditions targeted by the electrostatic precipitator.
If operation continues for a long time at low wind speed, an excessive amount of soot and dust will be collected in the dust collecting unit 4 compared to when dust is collected at the rated maximum wind speed. In the conventional control method, when forced drying is started at the maximum rated wind speed after cleaning of the first dust collection block 1a, the next block 1b is cleaned because the damper is closed, but only one dust collection block 1a is cleaned. If the dust collecting block 1c is not installed, excessively accumulated soot and dust will be temporarily scattered and the soot and dust concentration on the outflow side of the electrostatic precipitator will deteriorate.

The present invention is intended to solve this problem, and aims to reduce the amount of soot and dust scattered at the start of forced drying.

Means for Solving the Problem In order to solve this problem, the present invention provides a plurality of dust collection blocks and a variable air volume blower in an air path, and each of the dust collection blocks has a damper and a dust collection section. It is equipped with a water washing device for cleaning, and when the set cleaning cycle is reached, the damper is sequentially closed for each dust collection block to perform water washing, and after the cleaning of the first dust collection block is completed, the wind speed passing through the electrostatic precipitator is adjusted. The blower is operated so that the wind speed is 40 to 60% of the rated maximum wind speed, and after all the dust collection blocks have been cleaned, the blower is operated at the rated maximum wind speed for a certain period of time.

Effect: According to the above control method, the wind speed during the forced drying operation immediately after cleaning becomes 40 to 60% of the rated maximum wind speed, so that temporary re-scattering of soot and dust can be prevented.

6 Page Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

The structure of the electrostatic precipitator is the same as the conventional example shown in FIG. 1, so the explanation will be omitted. Fig. 2 shows a cleaning time chart of an embodiment of the present invention, in which a variable air volume blower is used so that the wind speed passing through the dust collector main body 1 becomes a value V set based on the ventilation status of the target equipment. 9 is air volume controlled. In the cleaning process, each dust collection block 8a to 8C is sequentially charged and cleaned, and after the cleaning of the first dust collection block 8a is completed, the variable air volume blower 9 is used to increase the wind speed passing through the dust collector main body 10 from 40 to 60, which is the maximum rated wind speed. %, and when cleaning of all dust collection blocks 1a to 1C is completed, the variable air volume blower 9 is controlled to such a volume that the wind speed passing through the dust collector body 1 reaches the rated maximum wind speed for a certain period of time. Forced drying is performed for a period of time t, and after the insulation of the charging section unit 3 and dust collecting section unit 4 is restored, a high voltage is applied and normal dust collecting operation begins. here,
The electrostatic precipitator is operated for a long time at a low air volume, and the dust collection unit 7
As shown in Figure 4, if the wind speed passing through the electrostatic precipitator body is 60% or less of the rated maximum wind speed, the amount of soot dust that is excessively collected on the page will be minimal. and 40% of the rated maximum wind speed from the graph in Figure 6.
In the above case, the drying time is longer than in the case of the maximum rated wind speed, but it has been confirmed through experiments that the proportion is small, and there is no problem in the upstream operation.

Effects of the Invention As is clear from the description of the embodiments above, according to the present invention, the rated maximum oil overflow speed of the dust collector main body is maintained at 40°C from the time the cleaning of the first dust collection block is completed until the cleaning of all dust collection blocks is completed. By controlling the operation of the variable air volume blower at ~60%, it is possible to clean the first collection block even if the dust collection unit has collected too much soot and dust due to the low wind speed operation for a long period of time in the pre-cleaning step 1. It is possible to prevent soot and dust from being re-dispersed from unwashed dust collection blocks during forced drying operation after completion.

Once all the blocks have been cleaned, all the soot and dust collected in the dust collection unit of each dust collection block is washed away, eliminating the problem of soot and dust re-scattering and allowing drying to be performed at the maximum rated wind speed. As a result, the drying operation time does not increase much compared to the conventional method.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of an electrostatic precipitator, Fig. 2 is a time chart showing an example of the water washing operation method in the electrostatic precipitator of the present invention, and Fig. 3 is a diagram of a conventional electrostatic precipitator. A time chart showing the water washing operation method, Fig. 4 is a characteristic diagram showing the wind speed passing through the dust collector body and the amount of re-splattered dust, and Fig. 5 is a characteristic diagram showing the wind speed passing through the dust collector body and the required time for drying the dust collecting unit. 1... Dust collector main body, 3... Charging unit, 4... Dust collecting unit, 6...
Water cleaning equipment, 6. River... High voltage power supply, 8a-8c...
...Dust collection block, 9. River...Variable air volume blower.

Claims (1)

[Claims] A plurality of dust collection blocks and a variable air volume blower are provided in the air passage, and each of the dust collection blocks is equipped with a water cleaning device that cleans the damper and the dust collection section, and the dust collection starts at a set cleaning cycle. The damper is closed one by one for each block and water cleaning is performed, and after the cleaning of the first dust collection block is completed, the wind speed passing through the electrostatic precipitator is 40 to 40% of the maximum rated wind speed.
A water cleaning method for an electrostatic precipitator in which the blower is operated so that the air flow rate is 60%, and after all the dust collection blocks have been cleaned, the blower is operated at the maximum rated wind speed for a certain period of time.