There is no simple “yes” or “no” answer to this, as many factors can influence equipment selection. Wet scrubbers and dry media dust collectors are two very different technologies used to capture combustible dusts generated when materials are divided into fine particulate through manufacturing processes. Facility managers and engineers face a balancing act of finding the best and most cost-efficient equipment to minimize explosion hazards while also keeping emissions below required thresholds to safeguard workers’ health.

1. WET SCRUBBERS,
A R E “ W E T ” D U S T C O L L E C T O R S ,
T H E B E S T T Y P E O F E Q U I P M E N T
F O R C A P T U R E O F C O M B U S T I B L E
D U S T S G E N E R A T E D
I N P O W D E R A N D B U L K
P R O C E S S I N G O P E R A T I O N S ?

2. WET SCRUBBERS AND
DRY MEDIA DUST COLLECTORS
ARE TWO VERY DIFFERENT
TECHNOLOGIES USED TO CAPTURE
COMBUSTIBLE DUSTS.

3. HIGH EFFICIENCY CARTRIDGE
MEDIA COLLECTORS
- MOST POPULAR FOR CAPTURING
INDUSTRIAL PROCESS DUST
- AVAILABLE WITH A WIDE CHOICE OF
FILTRATION MEDIA
- PERIODIC BURSTS OF COMPRESSED AIR
DISLODGE THE DUST FROM FILTERS
AND INTO A HOPPER

4. WET SCRUBBERS
- FILTER DUST BY IMPINGEMENT
WITH WATER DROPLETS
- THE SMALLER THE DROPLET, THE MORE
EFFICIENT THE SCRUBBER
- WHEN COMBUSTIBLE DUST PARTICLES
ARE CAPTURED INTO THE SCRUBBING
LIQUID, THEY ARE NO LONGER IN
CONTACT WITH OXYGEN, AND THE
COMBUSTIBLE DUST HAZARD
IS CONTROLLED

5. “iums”
ALUMINUM
HAFNIUM
MAGNESIUM
NIOBIUM
TANTALIUM
TITANIUM
ZIRCONIUM
As a general rule of thumb, wet scrubbers work best for light loading
applications, such as grinding of large particles; very sticky dusts; dusts
with high Kst values, typically of 150 Kst and above (Kst is defined as the
rate of pressure rise and is a commonly recognized measure of a dust’s
explosive power); and applications where dry collectors do not meet NFPA
standards, especially involving metal dusts known as the “iums”

6. Dry media collectors offer a number of
operational advantages over wet scrubbers.
Efficiencies are much lower on scrubbers when
dealing with 10 micron and smaller particles.
They require clean water, with a concentration
of dust particulate below five percent by volume,
which can become challenging in higher dust
loading applications. Wet systems also require
more maintenance and run at much higher
horsepower, especially when capturing particle
sizes of <2 micron. When hazardous dusts are
involved, disposing of wet materials may be
costlier than disposing of dry materials due
to regulations. Also, many metal dusts tend
to react with water to produce hydrogen gas,
requiring precautionary monitoring and control
of sump tanks.

7. Sometimes the choice between a wet vs. dry
media system is not clear-cut. Dust testing is
the first step in the decision-making process
to determine a dust’s physical, combustible
and explosive properties. A hazard analysis
will also be needed to identify the full range of
combustible dust deflagration, fire and explosion
hazards specific to the application. Methods for
hazard analysis are spelled out in applicable
NFPA standards.

8. VISIT OUR WEBSITE
TO LEARN MORE!
www.camfilapc.com

9. content provided by:
JOHN DAUBER
HANDTE PRODUCT MANAGER, AMERICAS
CAMFIL AIR POLLUTION CONTROL