Precipitators Can Meet the Proposed Standards - Hot Topic Hour August 25

If you missed the Hot Topic Hour yesterday and you are involved with electrostatic precipitators, we highly recommend viewing the 2-hour recording. Four speakers with more than 100 years of precipitator experience addressed important issues.

The anticipated requirement for mass particulate monitors and low emission limits will change decision making. However, fabric filters are not a clear choice. Bruce Scherer of EPRI said that meeting a 0.01 lb/MMBtu discrete particulate limit is a recommended path to meeting a 0.03 lbs/MMBtu total particulate limit. It will be harder to meet the 0.02 lbs/MMBtu of condensibles, so you need to keep discrete particulate very low.

Does this rule out precipitators? No. In fact it is uncertain whether a precipitator or a baghouse will emit less over an entire campaign. All of the speakers said that with modern controls, rigid discharge electrodes, and other features, a precipitator should operate at the same efficiency at the end of the campaign as at the beginning. What about baghouses? Does anyone know what the emissions of the baghouse are in the weeks before the bags are replaced? In order to address the reality of mass particulate monitoring and the concept of tons per year of emissions (as in Title 5 permits), utilities are going to have to obtain some facts on performance of equipment throughout the entire campaign.

Rob Kimberl, Vice-president for Operations & Technology at Clyde Bergemann EEC, affirmed that whether it is to achieve existing standards or trying to achieve new standards, an existing precipitator can be part of the particulate control strategy. Improving electrostatic precipitator performance can be as simple as performing routine maintenance to as complicated as adding a new chamber.  

Bruce Scherer, EPRI Project Manager for Program 76, Opacity and Particulate Control, discussed the ongoing research effort to provide quantifiable and reliable performance enhancements to existing electrostatic precipitators to meet the upcoming, stringent Utility MACT particulate regulations. Included were efforts on flow control innovations, power supply and hardware upgrade assessments, research on high resistivity and biomass blend ash collection enhancement and upgrades to ESPM, EPRI's precipitator performance model.

Greg Carleton of Pollution Control Services, Inc said that the majority of existing ESPs are not operating under their original design basis. Many existing ESPs have not been upgraded with modern operating philosophies or equipment. Taking a holistic approach in evaluating the precipitator in its current operating parameters permits a viable forward plan. It must take into consideration that the operating parameters have been modified as post combustion control equipment like SO₃, NO_x, and Hg control have been incorporated over the last few years.

Randy Cook, Manager of Business Development at Alstom Power, Inc, observed that contrary to popular belief, many of the existing ESPs can be rebuilt to meet the stringent emission requirements of pending regulations. A combination of multiple technologies for mechanical and controls upgrade will have to be used in most installations depending on fuel, existing ESP sizing and configuration. Changing electrode geometry, installation of high frequency power supplies, optimized rapping, advanced controllers with opacity optimization, power down rapping, and off flow rapping can achieve significant PM emission reduction without adding plate area or replacing the ESP by a fabric filter. If upgrade of the ESP alone cannot meet the emission requirement, it may be cost-effective to install a downstream polishing fabric filter.

The Bios and Abstracts are linked below.
BIOS AND ABSTRACTS - August 25, 2011.htm