Dry Scrubbers

How Dry Scrubbers Work

BIOREM provides dry scrubbers as stand-alone units or as a polishing stage following other pre-treatment technologies. Due to the relatively small bed volumes, media change-outs are quick and require little labor. BIOREM develops custom blends of adsorbents to match the requirements of the specific application and types of compounds being targeted.

Virgin activated carbon is the most popular dry scrubber media type. Sourced from coconut shells char or bitumous coal, it is steam activated to produce exceptionally high surface area. The high surface area results in the adsorption of high boiling point volatile organic compounds onto the surface of the media. Adsorption can be described as enhanced liquefaction due to London dispersion forces. BIOREM engineers are able to predict the adsorption capacity of activated carbon for any volatile organic compound using the Polanyi/Dubinin Potential Theory of Physical Adsorption, including multi-compound interactions and the effect of relative humidity.

Catalytic activated carbon is an another type of virgin activated carbon which has been surface modified to promote the catalytic oxidation of compounds prior to adsorption. It is most often used for the capture of hydrogen sulfide, which has low capacity on a traditional virgin activated carbon. The surface of a catalytic activated carbon converts hydrogen sulfide and other organic sulfur compounds to elemental sulfur which has a high adsorption capacity. Catalytic carbon effectively treats hydrogen sulfide without the thermal risks that are associated with caustic impregnated carbon.

Potassium permanganate impregnated aluminum oxide is used for the compounds that have a low boiling point and resulting low adsorption capacity. Similar to the mechanism in the catalytic activated carbon, the potassium permanganate oxidizes compounds to a solid which is strongly adsorbed. This media is well suited for polar and low molecular weight organic compounds as well as for organic sulfur compounds. Potassium permanganate is typically used as a second stage media after virgin activated carbon or catalytic activated carbon.

BIOREM dry scrubbers are available in a number of different configurations to meet site specific requirements:

 Standard ScopeFeatures
Vertical Single/Dual Bed
  • 304 stainless steel exhaust fan
  • Corrosion resistant fiberglass vessel
  • 2 second EBRT bed of activated carbon
  • Flexible design: arrangement can be modified, many additional features can be added
  • Reduced footprints
  • Least expensive package
Radial Bed
  • Same as Vertical system, but with higher air flows
  • High air flow capacity
  • Low pressure drop
  • Small footprint
Deep Bed
  • Pre-plumbed and pre-wired self-contained vessel
  • 304 stainless steel exhaust fan
  • Multiple adsorbent stages
  • Built-in thermal insulation and sound attenuation
  • Packaged unit
  • Easy carbon change-out using the vacuum ports
  • Contained design prevents public access to rotating equipment
  • Low profile design

Large variety of ancillary components that can be included as required:

Upstream Foul Air
  • Rotating desiccant bed dehumidifier
  • Heat transfer (heating/cooling)
  • Mesh pad grease/mist eliminator
  • Isolation damper
  • Expansion joints
  • Blower sound enclosure
  • Blower discharge silencer
  • Vessel & equipment materials of construction
  • Vessel Insulation
Instrumentation (local read or transmitting)
  • Differential pressure
  • Temperature
  • Hydrogen sulfide measurement
  • Carbon monoxide measurement
Field Services
  • Startup and operator training
  • System performance testing
  • Air sampling and analysis
  • Carbon media sampling and analysis

Low Cost Solutions

Dry scrubbers are well suited to a variety of applications. They can be utilized as stand-alone systems for low concentration applications or combined with other pre-treatment technologies to provide polishing and assurance during process upset conditions. Some of the applications which routinely use dry scrubbers for odor control are:
  • Organics Processing
  • Clean Room Air Supply
  • Agribusiness
  • Food & Beverage
  • Pharmaceutical
  • Surface Coatings
  • Petrochemical
  • Solid Waste Handling
  • Semiconductor
  • Chemical production facilities
  • Collection systems
  • Pumping stations
  • Headworks
  • Liquid Phase Treatment
  • DAF Systems
  • Equalization Basins
  • Biosolids Processing (thickening, dewatering)
  • Biosolids Storage Tanks