The electrostatic precipitator uses electricity to separate the dust particles in the gas. This dust removal equipment has the advantages of high dust removal efficiency, good temperature resistance, large amount of flue gas treatment and high degree of operation automation. It has been widely used in cement plants. Here are some factors affecting the efficiency of electrostatic precipitator from the aspects of operation and maintenance.

1、 Influence of secondary dust on dust removal efficiency

1. Secondary dust caused by vibration

Practice has proved that reasonable periodic rapping can improve dust removal efficiency. In many cases, gap rapping can reduce secondary dust by 1 / 2 ~ 2 / 3 compared with continuous rapping, and its effect can be obviously seen in the chimney. Increasing the capacity of dust collector can reduce the secondary dust during rapping, but with the increase of dust capacity, the settled dust will fall off automatically, resulting in secondary dust. For high specific resistance dust, it is not easy to release charge due to high resistance, which increases the negative charge on the surface of the dust layer and repels the later negatively charged dust. On the other hand, with the thickening of the dust layer, it can also form anti corona and reduce the dust removal efficiency.

As the dust accumulation degree of each electric field of electrostatic precipitator is different, the rapping cycle of each electric field is also different. The cross rapping method is adopted to prevent secondary dust caused by simultaneous rapping. Generally, the anodes of two adjacent electric fields are rapped at the same time, and the anode and cathode of the same electric field are rapped at the same time.

The rapping time is the same for each electric field, and the specific adjustment shall be considered according to the rapping strength, rapping mode, particle size and viscosity of dust. The purpose is to make the electric field polar plate and polar line clean and convenient for dust collection.

2. Secondary dust caused by air leakage of ash unloading valve

The air leakage of the ash discharge valve can cause the dust temperature to drop, affect the discharge, and cause serious wear of the ash discharge valve; On the other hand, it may cause secondary dust. The way to prevent air leakage of the ash unloading valve system is to use the particle level meter to control the ash unloading to prevent air leakage caused by dust unloading.

2、 Influence of flue gas temperature on dust removal efficiency

In addition to affecting the structure of electrostatic precipitator, the flue gas temperature mainly affects the dust specific resistance and dust removal efficiency. The dust specific resistance increases with the increase of temperature. Reducing the flue gas temperature can reduce the dust specific resistance and improve the breakdown voltage and dust removal efficiency. In addition, if the flue gas temperature is lower than the dew point, but the electric field inside the electric field condenses, resulting in creepage, more serious is the serious corrosion of the polar plate and polar line, reducing the service life of the equipment. Therefore, in general, the flue gas temperature is controlled at about 20 ℃ above the dew point temperature.

3、 Influence of control system on ESP efficiency

The performance of the electric control device of electrostatic precipitator has an important impact on the dust removal efficiency of electrostatic precipitator. When other conditions remain unchanged, the dust removal efficiency of electrostatic precipitator depends on the driving speed of dust removal, which increases with the increase of electric field strength. To obtain high dust removal efficiency, it is necessary to improve the electric field strength and make the voltage applied to the electrostatic precipitator as high as possible. Therefore, in order to ensure that the power supply voltage is maintained at a high level, the electric control device is required to adapt to the changes of the conditions of the precipitator and automatically adjust the output voltage and current to make the electrostatic precipitator operate in the fast tracking mode. It is not easy for workers to adjust the voltage to make the electric field voltage reach. Therefore, when selecting the electric control device, it is necessary to select the automatic high-voltage control device to prevent the low electric field voltage caused by untimely manual adjustment from affecting the dust removal efficiency of the electrostatic precipitator.

4、 Electrode ash cleaning

Timely removal of dust on the electrode is one of the important conditions to ensure the normal operation of the electrostatic precipitator, and it is also an important factor affecting the dust removal efficiency. For example, the effective driving speed when the electrode plate dust is deposited 10mm thick is 60% of that when it is 1mm thick. The amount of dust accumulated on the corona electrode is small, but it has a great impact on the film. If the dust is removed in time, the dust collector will stop working completely when the corona limit is scarred and the dust removal efficiency decreases. When the scarring reaches a certain degree. Therefore, it is very necessary to clean the dust of the electrode plate and electrode line of the electrostatic precipitator.

5、 Prevention of air leakage

The shell of the dust collector must be tight to minimize air leakage. If the air leakage increases, it will not only increase the load of the wind pole, but also reduce the dust removal efficiency due to the increase of the wind speed of the electric field. In addition, when dealing with high-temperature flue gas, the addition of cold air can reduce the local flue gas temperature above the leakage point temperature, which will lead to the corrosion of the components of the dust collector. The places with serious air leakage are generally at the connection of the inlet and outlet of the shell and the through wall of the rapping mechanism, Quartz casing and inspection hole ash unloading valve, etc. Air leakage of ash hopper and ash unloading valve may cause secondary dust. For the head electrostatic precipitator, due to working under high negative pressure, special attention should be paid to the sealing of the precipitator.