How does an electrostatic precipitator (ESP) remove particulates?

• A. It charges particles in flue gas and collects them on oppositely charged plates using an electric field.
• B. It chemically reacts with particulates to dissolve them.
• C. It uses magnetic fields to attract metal particles.
• D. It filters particulates through a fabric bag.

Answer: (A)

The basic idea tested is that an electrostatic precipitator removes particulates by charging them in the flue gas and pulling the charged particles to oppositely charged plates with an electric field. A high voltage creates a corona discharge that charges the particles as gas flows through. The charged particles then migrate toward collector surfaces that are oppositely charged (or grounded), where they adhere. Periodic rapping or vibration frees the accumulated ash, which falls into hoppers for disposal. This approach is especially effective for fine particles in large gas streams and tends to have a relatively low pressure drop. It doesn’t chemically react with the particulates, rely on magnetic attraction, or use a fabric bag filtration mechanism like a baghouse.