NR2221

NEWS RELEASE                                                                                                                APRIL 2016

Multibillion Dollar Hot Gas Filtration Market will be Technology Driven

The large market for hot gas filters is growing and changing.  The drivers are:

  • More stringent air emission limits on particulate
  • Desirability to integrate filtration with DeNOx and acid gas capture
  • Development of new systems to remove dust at high temperature
  • Development of systems to remove multiple pollutants
  • Opportunities to improve efficiency of processes and reduce greenhouse gases

There are a number of ways to remove dust from air.  Dry precipitators presently remove more dust than all the other technologies combined.  On the other hand, the market share for dry precipitators has dropped from 90 percent decades ago to closer to 50 percent now.  In the future, the dry precipitator share will drop even farther as power plants switch to fabric filters.

Industry <450oF Filters 850oF Filters

Catalytic Filters

Dry Precipitators Scrubbers Wet Precipitators
Coal-fired Power P P P P S S  P
Waste-to- Energy P P P P S P S P
Cement P P P P    
Steel P P     S P  

Sewage Sludge Incineration

        P S
Coal Gasification   P     P P
Natural Gas Processing P          
Biomass Firing P P P P S P S P
Glass Furnaces P P P P S  
Gas Turbine Intake P          

P = primary, S = supplementary (yellow = most used  blue = most promising)

The industry has responded to these drivers with a range of new technologies.  It is, therefore, going to be a challenge for the operator to select the best option for his specific situation.  Here are some of the new choices:

  • Membranes and laminates with microfibers to achieve higher efficiency at equivalent pressure drop.
  • Filter media to best deal with the large load increases caused by direct sorbent injection of activated carbon or lime.
  • Filter media to cope with sulfuric acid condensate as coal-fired boilers burning high sulfur coal are utilizing filters.
  • Compact pleated filters to fit inside the shell of a precipitator.
  • Filters to remove organics as well as dust.
  • Filters to reduce NOx as well as capture dust.
  • Filters to operate at 850oF.
  • Filters to operate at 500oF.

Here are some of the developments in specific industries:

Coal-fired power:  DSI, catalytic filters, removal of dust prior to air preheater, insertion of filter bags in existing precipitators, membranes for higher efficiency, consideration of a venturi scrubber/wet precipitator option instead of DSI fabric filter;  SBS injection and lowering air heater temperature to where a bag with 250oF limits could be used.

Waste-to-Energy: Mercury and acid gas capture along with dust, elimination of the first-stage filter with a system to produce salable hydrochloric acid and valuable metals.

Cement:  Coping with hazardous waste and sewage sludge as well as kiln dust, separate loop for mercury removal and capture, options to extract phosphorous from clinker kiln dust.

Steel: Capturing fugitive dust, replacing precipitators with fabric filters, dealing with sinter plant variables.

Sewage Sludge:  Improving scrubber dust removal and final capture in WESP.

Coal Gasification:  Ceramic filter with improved performance, venturi scrubber and production of rare earths and 30 percent hydrochloric acid.

Natural gas processing:  Coalescing filters for droplet removal, ionic liquid impregnated pellets for mercury removal, filters to remove fines leaving carbon bed filters.

Biomass firing:  Filters to deal with sticky contaminants released by combustion.

Glass Furnaces:  Use of the catalytic filter with DSI injection using high reactivity lime.

Gas turbine intake:  Filters to resist the salts and moisture of offshore turbine locations, HEPA efficiency to reduce turbine maintenance, membranes vs. nanofiber laminates, static vs. pulsed.

Filter selection decision guides in each industry will be discussed in a Hot Gas Filtration Hot Topic Hour slated for April 21, 2016.      

Click Here to Register