Particles in the low-resistivity area lose their charge as soon as they arrive at the collecting plate, so they are re-entrained in the dust collection area, and the dust collection efficiency is greatly reduced. (Re-entrainment).
Dust collection efficiency and electrical resistivity of dust.
The dust collection efficiency of Electrostatic precipitator is affected by the electrical resistivity of the dust collected.
In the normal resistivity area, the dust collection efficiency is high, so dust collection is stable. Most of the aerosols handled by Electrostatic precipitator are in this electrical resistivity area.
Electrostatic precipitation is a method of dust collection that uses electrostatic forces, and consists of discharge wires and collecting plates. A high voltage is applied to the discharge wires to form an electrical field between the wires and the collecting plates, and also ionizes the gas around the discharge wires to supply ions. When gas that contains an aerosol (dust, mist) flows between the collecting plates and the discharge wires, the aerosol particles in the gas are charged by the ions. The Coulomb force caused by the electric field causes the charged particles to be collected on the collecting plates, and the gas is purified. This is the principle of electrostatic precipitation, and Electrostatic precipitator apply this principle on an industrial scale. The particles collected on the collecting plates are removed by methods such as (1) dislodging by rapping the collecting plates, (2) scraping off with a brush, or (3) washing off with water, and removing from a hopper.
Therefore, an important factor when planning Electrostatic precipitator is the electrical resistivity of the dust to be collected.