Electrostatic precipitators
Plate-type and tube-type ESPs
Also known as plate type ESP, tube type ESP.
Plate-type and tube-type describe the two principal collecting-electrode geometries of an electrostatic precipitator.
Plate-type ESPs
Plate-type ESPs have vertical parallel collecting plates spaced 250–400 mm apart, with discharge electrodes hanging in the gas-flow lanes between them. They dominate dry ESP installations on coal-fired boilers, cement kilns, WtE, biomass and sinter plants. Gas flows horizontally; cleaning is by rapping or sonic horns.
Tube-type ESPs
Tube-type ESPs use vertical cylindrical collecting tubes with a single discharge electrode along the axis of each tube. Gas flows vertically. The geometry is preferred for wet ESPs (WESPs), acid-mist scrubbing and small specialised duties.
Cleaning differences
Plate-type fields benefit from low-frequency sonic horns projecting along the gas-flow direction to dislodge dust across multiple plate rows. Tube-type fields use water in WESP service; their dry equivalent is uncommon outside specialised metallurgical and chemical applications.
Related terms
Related terms
- Electrostatic precipitatorAn ESP removes particulate from flue gas by charging dust and collecting it on plate electrodes. Sonic horns are widely used to dislodge ash from plates and to keep hoppers from bridging.
- Wet electrostatic precipitatorA wet electrostatic precipitator continuously washes its collecting surfaces with water, used for sub-micron particulate, acid mist and sticky aerosols downstream of FGD or biomass scrubbers.
- Collecting electrodeThe collecting electrode is the grounded plate or tube on which charged particulate accumulates inside an ESP. Dust must be released to hoppers without re-entraining into the gas stream.
- Discharge electrodeThe discharge electrode is the high-voltage electrode that generates the corona discharge inside an ESP. Charged dust drifts from it to the collecting plates.