Fabric Selection for Coal-fired Boilers was the Hot Topic on October 28, 2010
A large group of attendees heard five very good presentations related to the selection of the best filter media to meet the various coming regulations for PM2.5. Attendees agreed that the fundamental filtration capability of the vast majority of fabrics available today, as measured by laboratory tests, far exceeds any existing or expected emission control requirement and the performance of many is below the minimum detectable limit of the test methods. Several presenters pointed out that while the results of these evaluations can be a good guide for filter efficiency and pressure drop, the actual performance of filter material will rarely achieve the levels seen in these tests. This is because the actual performance is dependent on many factors related to the specific site conditions. This causes a concern in the industry that regulators will assume that lab test results are indicative of actual performance and expect the same performance at every installation. Dr. McKenna indicated that because filter media performance was so good, future enforcement will most likely be focused on plant baghouse O&M. He also stated that it will be important to demonstrate what aspects of O&M plans are practical and valuable, so that regulators do not make these plans an operational nightmare.
The presenters’ slides are shown below each individual’s presentation. They will soon be incorporated into our new database.
Dr. John D. McKenna, Ph.D., principal and founder of ETS, Inc., reviewed the regulations for PM2.5 and the filter media options for complying with the coming emission limits. He also discussed the standard test methods available for evaluating the performance of various filter materials including EPA’s ETV Generic Verification Protocol for Baghouse Filtration Products, ASTM D 6830, and the proposed ISO method that he said should be issued next March after ten years of work. He reviewed the elements of a bag quality control program and emphasized that a good QA/QC program will be essential to obtaining compliance and efficient baghouse operation.
Ø The Impact of PM2.5 Legislation on Filter Bag Performance Alternatives
John McKenna - ETS, Inc - 10-28-10.pdf
Charles Barranger, Senior Consultant at EPSCO International, Inc., discussed the styles of baghouses in use, QA/QC procedures and criteria for selecting filter media. When asked how cost figures into the selection criteria, he stated that life cycle cost is very important but it needs to be balanced against the required efficiency. He also offered techniques for improving the performance of filters to achieve lower particulate emissions.
Ø Low Particulate Emissions – Short and Long Term
Charles Barranger - EPSCO International, Inc. - 10-28-10.pdf
Chet Moon, Technical and Applications Manager at Toray Fluorofibers (America), Inc., presented performance data for the range of fibers Toray offers for filtration applications. He said that currently Toray PPS TORCON® is the most suitable fiber to meet most of the filtration needs of coal-fired boilers. However, in the future it may be necessary to utilize one of the more expensive Tefaire® and Teflon® products to meet the regulated limits.
Ø TORAY High Performance Fibers for Low Sulfur Coal Applications
Chet Moon - Toray Fluorofibers - 10-28-10.pdf
Tom Anderson of Midwesco Filter Resources TDC Filter emphasized that a user should select the filter media that gives the lowest lifetime cost and meets the efficiency requirements. He also provided many recommended installation and operational dos and don’ts for achieving optimum baghouse operation.
Ø Filter Selection
Tom Anderson - Midwesco - 10-28-10.pdf
John Darrow, Energy Market Specialist at W.L. Gore & Associates, Inc., described the characteristics of ePTFE membrane filter media and compared them to other media available. He said that 35 EGUs were now using this material. However, because of higher material cost, it was not necessarily the best solution for every power plant. He described a four-step process to go through to determine what the best media would be for a specific power plant to achieve the objective – “Getting the Lowest Annualized Cost w/o Emissions Problems.”
Ø How to get the most out of your Baghouse with Gore ePTFE Filter Media
John Darrow - W.L. Gore & Assoc. 10-28-10.pdf
The BIOS, PHOTOS, and ABSTRACTS can be viewed as follows: