Improving ESP Performance is Hot Topic Hour on January 20, 2011 at 10 a.m. CST
Several new regulations currently being proposed or implemented will force fossil-fueled power plants to further decrease particulate emissions to levels close to the detection limit for current measurement methods. The new 24-hour fine particle PM2.5 National Ambient Air Quality Standards (NAAQS) of 35µg/m3 that became effective in December 2009, the Utility MACT rule expected to be promulgated in early 2011 setting stringent limits on the emissions of NOx, SO2, SO3 and other acid gases, fine particulates (PM2.5), trace elements, volatile organic compounds (VOCs) and other HAPs, the Federal PM2.5 NSR Rule that establishes requirements for states for implementing NSR for PM2.5 (including PM2.5 precursors: SO2, NOx, VOC and ammonia) and the proposed "Federal Implementation Plans to Reduce Interstate Transport of Fine Particulate Matter and Ozone,” (Transport Rule) issued in August 2010 to replace the Clean Air Interstate Rule (CAIR) will individually and jointly have serious consequences for coal-fired power plants. Some states have already indicated that they will seek to institute PM2.5 NSR regulations that are more stringent than the federal standards.
Electrostatic precipitators (ESPs) are the most commonly used effective, and reliable particulate control devices for coal-fired power plants. Although electrostatic precipitators generally capture 99.5 percent of the particles from the flue gas in terms of mass volumes, this will probably not be adequate to meet the future regulations for PM2.5. In addition, many of the ESPs in use today are old and undersized for the task at hand or are operating with a different fuel (low sulfur) and load than they were originally designed for. Other than general deterioration of the precipitator, several design factors can lead to less-than-desired performance. These can include small size and consequent short treatment time and low specific collection area, discharge electrode configuration, collecting plate spacing, non-uniform flow, and inadequate electrical control systems.
Fortunately there are several methods that can be employed to increase the efficiency of an existing ESP short of complete replacement. (Although a few of the older smaller units may need to be replaced.) Over the past ten years development of better power supplies, especially High Frequency Switched Mode Power Supplies (HFSMPS), better electrode designs, improvements to the mechanical design and modeling of air flow to improve gas velocity and velocity distribution as well as flue gas conditioning, now offer the possibility to significantly increase the removal of fine particulates and other pollutants. Companies that supply precipitators and their key components, as well as companies that provide services to maintain and tune up precipitators, have also developed methods and equipment to fine tune precipitators to both improve the performance and to reduce the power required to achieve this performance.
The following speakers will describe the various options for improving the performance of existing precipitators at minimal cost, the new technologies that have been or are being developed to improve the performance of older and new ESPs and the performance of newly designed and installed ESPs, as well as newly upgraded or retrofitted units relative to achieving the expected PM2.5 emission limits.
Dr. Yougen Kong, P.E., Technical Development Manager at Solvay Chemicals, Inc., will describe a better alternative to SO3 for conditioning electrostatic precipitators. Using SO3 to condition the flue gas of boilers burning low-sulfur coal is going to face a new challenge: Mercury control, since SO3 inhibits the mercury removal by either flyash or powdered activated carbon (PAC). A better alternative is to inject trona into flue gas upstream of hot-side or cold-side ESP. It can lower the resistivity of flyash and solve the problem of back corona due to “sodium depletion” of hot-side ESP. In addition, the added trona can remove SO3 and thus improve the mercury removal. The trona addition system is simple and its capital cost is much lower than that of SO3 production and injection system.
Mick Chambers, Southern Environmental, Inc, will discuss ESPs and mercury reduction. The purpose of this presentation is to update the attendees on developments in the utility industry which are suggesting that the currently favored strategy of replacing older ESPs with fabric filters, when mercury reduction is a concern may no longer be the optimum solution. Better performing ESPs, along with new mercury control technology, indicates that more practical approaches using upgraded ESPs and halogen-based additives are rapidly gaining commercial acceptance. While actual operating data for installations utilizing these technologies is not widely available in the public domain due to intellectual property issues, sufficient anecdotal evidence exists to warrant serious investigation of ESP upgrades before proceeding directly to fabric filter retrofits.
Steve Jaasund, Manager, Geoenergy Division, A. H. Lundberg Associates, will discuss wet ESPs for particulate control enhancement from utility boilers. New emission control rules that are expected from the U.S. EPA will put increasing pressure on utility-boiler operators. Wet electrostatic precipitator technology is a logical add-on alternative to help meet these rules. This is particularly true if boiler emissions are already being treated with wet FGD. This presentation will explore the pros and cons of wet ESPs in the utility environment with an emphasis on retrofit issues.
Greg Carleton, President, Pollution Control Services, Inc.
Jonathan (Jon) Barr, Vice-President, Sales & Marketing, ADA-ES (ADA Environmental Solutions LLC)
To register for the "Hot Topic Hour" on January 20, 2011 at 10 a.m. CST (Chicago time), click on: on: http://www.mcilvainecompany.com/brochures/hot_topic_hour_registration.htm
Bob McIlvaine
President
847 784 0012 ext 112
rmcilvaine@mcilvainecompany.com