Electrostatic Precipitator Gas Flow Distribution
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The performance of any electrostatic precipitator (ESP) is contingent on the uniform distribution
of the gases and suspended particulate entering the ESP. |
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Poor gas flow will result in poor ESP performance and high stack opacity. Good gas flow distribution
is essential to optimum ESP efficiency. The best-constructed and aligned ESP will not provide the
performance levels expected if the gas flow distribution is not within standards.
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If the gas flow is not uniform through the precipitator, this will result in high velocity zones in the gas treatment
region resulting in opacity spikes and excursions as a result of re-entrainment and scouring. Hopper sweepage can also
occur if the gases are being forced in the hoppers. Also, the total effective collection zone of the ESP will not be
utilized if the gases are not being distributed through the ESP uniformly. This will underutilize the ESP and result
in poor performance.
Today's ESPs built by Hamon research-Cottrell are provided with the proper gas flow corrective devices to insure good
gas flow distribution as defined by ICAC. These devices are carefully selected by conducting a gas flow model study
of the ESP and related ductwork and scaling the results to the full size unit.
If your Electrostatic Precipitator electrical readings are good and your stack emissions are high, this condition may
suggest a problem with the gas flow distribution to the ESP.
- Tips for maintaining good gas flow distribution
- During an outage, make sure that all gas flow devices are clean and not built up with dust.
- Make sure all perforated plate holes are open and not plugged off.
- Make sure that the bottom floors of all plenums are not built up with dust. Sweep or vacuum out all dust that may be built up on the plenum floors.
- Make sure all rappers or vibrators installed on perforated plates are in good working order.
- Make sure all horizontal surfaces (such as splitter vanes and egg crates) are not built up with dust.
- During an ESP inspection, look at the collecting plate surfaces for any signs of scouring. This may be suggestive of high velocity zones.
Quick links to:
High Voltage Energization System
Electrical Readings
Dust Removal System
Rappers
Corrosion
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