Chemical Engineering May 2012 - 22

Technology Showcase
BOC, which is now part of The
Linde Group (Munich, Germany;
www.linde.com) patented a system to
combine the ozone generator with a
scrubber that would absorb the soluble
NO2 created by the NOx reaction
with ozone. This system was licensed
to DuPont (Wilmington, Del.; www.dupont.com),
which has sold a number of
World Region
Total
Africa
CIS
East Asia
Eastern Europe
TABLE 4. POWER PLANT ABSORBER REVENUES, $ MILLIONS
2012 World Region
7,847 Middle East
77
NAFTA
0.00 South & Central America
4,742
319
West Asia
Western Europe
systems for petroleum refineries.
Another approach is to use hydrogen
peroxide instead of ozone. Some
breakthroughs by the URS Corp. (San
Francisco, Calif.; www.urscorp.com)
and FMC Corp. (Philadelphia, Pa.;
www.fmc.com) partnership have re2012
108
1,854
37
88
618
sulted
in efficient removal of the NO2
in downstream scrubbers where there
is a high sulfite content in the scrubbing
liquor. Inhibited oxidation lime
systems have high sulfite levels. This
technology is cost effective for smaller,
older utilities.
One of the biggest applications for
ozone technology is lift stations, which
are used to elevate sewage for further
gravity flow to a sewage treatment
plant. There are other odor emission
points in the treatment process that
can be ducted to small units or to a
combined large unit
Ozone can be used to reduce both
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22 CHEMICAL ENGINEERING WWW.CHE.COM MAY 2012
Author
Robert McIlvaine has been
producing market information
reports for the environmental,
energy, contamination
control and process
industries for over 30 years.
Visit his website at: www.
mcilvainecompany.com for
more information.
H2S and NH3. The wet scrubber approach
using ozone has been compared
to biofilters with a pilot plant
installed by Xylem Wedeco GmbH
at a municipal plant in Osnabrueck,
Germany. Results were reported by A
Reid, J. Mielcke and M. Kampmann of
Wedeco at the IOA World Congress in
Strasbourg in 2005.
During the testing of the pilot
scrubber with ozone versus the existing
biofilter, the biofilter achieved
an 82% ammonia reduction, while
the scrubber with ozone achieved
an efficiency of 98%. The reduction
in H2S was also superior in the wet
pilot unit. This leads to the conclusion
that the wet scrubber with
ozone should be selected when anticipated
odor levels are high or emission
limits are low. Since there is a
very low odor threshold (0.002-0.15
ppm) for H2S and a 5 ppm threshold
for ammonia, high reduction levels
are often required.
The estimated cost of the scrubbers
is higher at €0.70 compared to €0.55
per 1,000 m3. But the cost is not prohibitive
and the efficiency is necessary
in many cases.
■
Edited by Dorothy Lozowski

http://www.linde.com http://www.urscorp.com http://www.du http://www.pont.com http://www.fmc.com http://www.cranechempharma.com http://www.mcilvainecompany.com http://adlinks.che.com/40267-10 http://WWW.CHE.COM

Chemical Engineering May 2012

Table of Contents for the Digital Edition of Chemical Engineering May 2012