NEWS RELEASE                                                                                                    DECEMBER 2013

Fabric Filter Innovations Keep Changing the Industry

Constant innovation of filters and media used to capture pollutants from exhaust stacks results in many new products and new applications.  These innovations are continually analyzed and reported in the Fabric Filter Knowledge System published by the McIlvaine Company.

Innovations can be classified as:

  • Expanding the range of pollutant types which can be captured
  • Increasing efficiency of capture
  • Decreasing balance of plant costs
  • Decreasing the cost of ownership

The expansion of the range of pollutants captured has been a function of both collector design and media.  The biggest expansion has been to capture acid gases.  Reagents are injected ahead of the fabric filter. They react with the acid gases to produce sulfates, chlorides and fluorides which can then be captured in a downstream fabric filter.  The waste-to-energy, aluminum and power industries are now widely using this technology.

The collector innovations have been to handle the much larger quantity of particulate which is being captured.  The media developments have been to find materials which will stand both the temperature and acidic conditions which have been encountered.  PPS has proven to be an answer.

The development of microfibers, nanofibers and films has allowed media to capture sub-micron particles with modest pressure loss across the medium. With the greater emphasis on regulating particles smaller than 2.5 microns in diameter, these innovations are important.

The introduction of media which can operate economically at 850oF creates opportunities to reduce total cost of operation for boilers and furnaces. If the dust can be extracted at high temperatures, then conventional heat exchangers can be used to extract the valuable heat.  Thermal efficiency can be greatly increased if the heat is utilized rather than being converted to a steam plume exiting the stack.

The biggest balance of plant saving is the elimination of selective catalytic reduction for NOx control. By embedding catalyst into the filter media, the filter can provide both particulate control and NOx reduction. Clear Edge and W. L.Gore are two companies developing this technology.

Decreasing the cost of ownership has been achieved by the improvement in cleaning mechanisms and media.  Filter bag life is extended and the average pressure loss across the bag is reduced.

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