In flue streams from coal-
fired power generators,
mercury exists in three
forms: elemental, the+2
oxidation state (Hg
++
), and
attached to particulatematter. Inmany
instances, Hg
++
will react with sulfur com-
pounds, nitrogen, chlorine, and/or oxygen, to
produce sulfurous, nitrous, chloride, and oxide
mercury species. Elemental and oxidizedmercu-
ry easily can be lost to reactions and adsorption
on the inner surfaces of monitoring equipment.
In order to accurately sample and quantifymer-
cury in all forms, it is important to use inert
sample pathways. Laboratory testing and field
results have proven that Sulfinert
®
treated sam-
pling and testing equipment is essentially inert
to activemolecules
4
, and customer field testing
has shown Sulfinert
®
treatment to greatly
reduce interactions of steel componentswith
mercury.
Siltek
®
/Sulfinert
®
treatment applies an inert
barrier coating over the entire surface of a steel
component, regardless of its geometry. It can
be applied tomany of the components in amer-
cury sampling stream, including probe tubing,
impingers, fittings, filters, housings, and trans-
fer tubing. A typical sampling train schematic is
shown in Figure 1. Application of
Siltek
®
/Sulfinert
®
treatment to all of the compo-
nents of a stack or continuous emissionmoni-
toring systemwill greatly improve analytical
reliability and sensitivity, andwill be needed as
regulations are brought on line and emission
quotas are enforced.
Similarly, a Siltek
®
/Sulfinert
®
treated sampling
systemwill improve the reliability of data for
sulfurous and nitrous oxides (SOx andNOx).
Emissions of SOx andNOx compounds from
coal-fired power generators are stringently
regulated, and there currently aremany sys-
tems in the field tomonitor these compounds.
Aswithmercury, it is difficult to reliably transfer
these compounds through untreated sampling
equipment.
In addition to preventing adsorption of reactive
compounds in sampling pathways,
Siltek
®
/Sulfinert
®
treatment will act as a barrier,
protecting the steel and prolonging the lifetime
of the treated equipment.The value of
Siltek
®
/Sulfinert
®
treatedmonitoring equipment
PreventAdsorptionofMercury,
Sulfur, andNitrogenCompounds
inStackandMonitoringEquipment
Improve reproducibility,
protectequipment
Siltek®/Sulfinert® treatment adds
value toyour process:
•Improve analytical sensitivity and reliability
formercury, SOx, or NOx compounds.
•Eliminate costly retests.
•Maximize scrubber performance.
•Protect against corrosion—increase
component lifetime.
•Apply to existing equipment; will withstand
temperatures to 400ºC.
ApplicationsNote
110Benner Circle • Bellefonte, PA 16823
800-356-1688•814-353-1300• fax: 814-353-1309
Restek
Performance
Coatings
Improveanalytical reliabilityand
prevent corrosion, using
Siltek®/Sulfinert® treatedcomponents
Table I
Typical costsof addingair pollution
controls toa1969vintage75MW cyclone fired
boiler (U.S. dollars,millions).
2
Item
Wet Scrubber Dry Scrubber
SCR
23.8
23.8
PJFF and scrubber
22.4
16.1
ACI
—
0.7
ID fans
2.6
2.6
Stack
2.8
2.8
Balanced draft conversion
7.7
7.7
Auxiliary power upgrades
0.9
0.85
Subtotal capital cost
60.2
51.75
Asbestos abatement
2.0
2.0
Total capital cost
62.2million 53.75million
Table II
Typical costsof various sampling
methods (U.S. dollars).
3
Method
Approx. Cost of Analysis
USEPA29
300
USEPA 101A
100
ASTMD6784-02
250
USEPA324
430
FAMS
640
ercury has a significant impact on human
health, andmercury contamination in the
environment is a growing concern. Coal-fired
power generators are one of themajor sources
of mercury emissions into the environment.
1
The
United States is actively developing regulations,
limits, and control measures formercury emis-
sions from coal-fired power generators.
As regulations and guidelines formonitoring
and controllingmercury emissions are devel-
oped and implemented, proper equipment will
be needed for accurate sampling and analysis.
A typical coal-fired plant may spend up to $62
million tomeet emission regulations (Table I).
2
In addition, inmany stack environments com-
mon to coal-fired power generators, monitoring
equipment is exposed to sulfuric and hydrochlo-
ric acids, which leads to corrosion and damage.
Regular upkeep and preventivemaintenance of
testing equipment is costly. Also, analytical
testing costs can be substantial. Recent studies
have shown a per-test cost of $100-$640U.S.
dollars (Table II).
3
Finally, the costs of inaccu-
rate analysis could have broad financial and
environmental repurcussions.
M
