•
3
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2005vol. 2
The United States Environmental Protection
Agency (US EPA) is actively developing regula-
tions, limits, and controlmeasures formonitoring
and controllingmercury emissions from coal-fired
power generators—one of the major sources of
mercuryemissions into theenvironment.¹As these
regulations and guidelines are developed and
implemented, proper equipment will be needed
for accurate sampling and analysis. Testing costs
formercury canbe substantial (Table 1)², so inac-
curate analyses can have financial as well as envi-
ronmental repercussions.
In flue streams from coal-fired power generators,
mercury exists in three forms: elemental, the +2
oxidation state (Hg
++
), and attached to particulate
matter. Hg
++
often reacts with sulfur compounds,
nitrogen, chlorine, and/or oxygen, to produce sul-
furous, nitrous, chloride, and oxide mercury
species. Elemental and oxidizedmercury can easily be lost to reactions and
adsorptionon the inner surfaces ofmonitoring equipment. Inorder to accu-
rately sample and quantifymercury in all forms, it is important to use inert
sample pathways. Laboratory testing and field results have proven that
Sulfinert® treated samplingand testing equipment is essentially inert toactive
molecules³, includingmercury.
Siltek®/Sulfinert® treatment can be applied tomany of the components in a
mercury sampling stream, including probe tubing, impingers, fittings, filters,
housings, and transfer tubing (Figure 1). Treating all of the components of a
stackor continuous emissionmonitoring systemwill greatly improve analyt-
ical reliability and sensitivity,whichwill beneeded as regulations arebrought
on line and emission quotas are enforced. Fast and accurate testing, without
re-work, can save a great deal of time andmoney.
Similarly, a Siltek®/Sulfinert® treated sampling systemwill improve the relia-
bility of data for sulfurous oxides andnitrous oxides (SO
x
andNO
x
).Aswith
mercury, it isdifficult to reliably transfer these compounds throughuntreated
sampling equipment.
In addition to preventing adsorption of reactive compounds,
Siltek®/Sulfinert® treatment will act as a barrier, protecting and prolonging
the lifetime of treated equipment. The durable layer will withstand tempera-
tures to400°C.
We offer Siltek®/Sulfinert® treated tubing, sample cylinders, and other com-
ponents from stock; to discuss custom treatment of system components,
please contact theRestekPerformanceCoatings team.
AccuratelyMonitorMercury-Sulfur-NitrogenCompounds
Siltek®/Sulfinert®Treatment PreventsAdsorptionofMercury, SulfurOxides,
orNitrousOxides inEmissionMonitoringEquipment
By Gary Barone, Restek Performance Coatings DivisionManager, David Smith, RPC Chief Scientist, andMartinHiggins, RPC Chief Engineer
• Improvedanalytical reliabilityand sensitivity formercury, SO
x
, orNO
x
compounds.
• Protection from corrosion—longer component lifetime.
• Apply tonewor existingequipment.
Table I
Typicalcostsofmercurysampling (U.S.).²
Method
Approx. Cost of Analysis
US EPA 29
$300
US EPA 101A
$100
ASTMD6784-02
$250
US EPA 324
$430
FAMS
$640
Figure1
Highlighted componentsof amercury sampling train,
4
andall tubing in the system, canbeSiltek®/Sulfinert® treated.
Restek offers treated and untreated tubing, fittings, and valves, passive air sampling kits, air sampling canisters
andminiature air canisters, sample loops, andmore. Formore information, request our catalog or visit us
online.
References
1. Pottinger, M., S. Stecklow, and J.J. Fialka,
Invisible Export, AHidden
Cost of China’s Growth: MercuryMigration
TheWall Street Journal
Online, Dec. 17, 2004.
2. Serne, J.C.,
AnOverview and Comparison of AvailableMercury
Emission Test Methods for Boilers
Symposium on Air Quality
Measurement; Methods andTechnology 2005, San Francisco, CA; Air
&WasteManagement Association. paper no. 439, pg. 9.
3. Barone, G., M. Higgins, D. Smith, S. Rowan,W.J. Gross, and P. Harris,
The Surface for Sulfurs
Hydrocarbon Engineering, Dec. 2004, pp 47-
50.
4. ProposedMethod 324.
Determination of Vapor Phase FlueGas
Mercury Emissions from Stationary Sources UsingDry Sorbent Trap
Sampling
United States Environmental Protection Agency.Washington,
D.C. p. 5.
