Precipitator Components

All electrostatic precipitators, regardless of their particular designs, contain the following essential components:

• Discharge electrodes

• Collection electrodes

• High voltage electrical systems

• Rappers

• Hoppers

• Shell

Discharge electrodes are either small-diameter metal wires that hang vertically (in the electrostatic precipitator), a number of wires attached together in rigid frames, or a rigid electrode made from a single piece of fabricated metal. Discharge electrodes create a strong electrical field that ionizes flue gas, and this ionization charges particles in the gas.

Collection electrodes collect charged particles. Collection electrodes are either flat plates or tubes with a charge opposite that of the discharge electrodes.

High voltage equipment provides the electric field between the discharge and collection electrodes used to charge particles in the ESP.

Rappers impart a vibration, or shock, to the electrodes, removing the collected dust. Rappers remove dust that has accumulated on both collection electrodes and discharge electrodes. Occasionally, water sprays are used to remove dust from collection electrodes.

Hoppers are located at the bottom of the precipitator. Hoppers are used to collect and temporarily store the dust removed during the rapping process.

The shell provides the base to support the ESP components and to enclose the unit.

Figure 1 shows a typical ESP with wires for discharge electrodes and plates for collection electrodes. This ESP is used to control particulate emissions in many different industries.

                         

                                 Figure 1 - Typical Dry Type ESP