ASTM D5954-98(2006)
(Test Method)Standard Test Method for Mercury Sampling and Measurement in Natural Gas by Atomic Absorption Spectroscopy
Standard Test Method for Mercury Sampling and Measurement in Natural Gas by Atomic Absorption Spectroscopy
SIGNIFICANCE AND USE
This test method can be used to measure the level of mercury in natural gas streams for purposes such as determining compliance with regulations, studying the effect of various abatement procedures on mercury emissions, checking the validity of direct instrumental measurements, and verifying that mercury concentrations are below those required for natural gas processing and operation.
Adsorption of the mercury on gold-coated beads can remove interferences associated with the direct measurement of mercury in natural gas. It preconcentrates the mercury before analysis thereby offering measurement of ultra-low average concentrations in a natural gas stream over a long span of time. It avoids the cumbersome use of liquid spargers with on-site sampling, and eliminates contamination problems associated with the use of potassium permanganate solutions.3 ,4 ,5
SCOPE
1.1 This test covers the determination of total mercury in natural gas at concentrations down to 1 ng/m3. It includes separate procedures for both sampling and atomic absorption spectrophotometric determination of mercury. The procedure detects both inorganic and organic forms of mercury.
1.2 The values stated in SI units are to be regarded as the standard.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D5954 − 98(Reapproved 2006)
Standard Test Method for
Mercury Sampling and Measurement in Natural Gas by
1
Atomic Absorption Spectroscopy
This standard is issued under the fixed designation D5954; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope abatement procedures on mercury emissions, checking the
validity of direct instrumental measurements, and verifying
1.1 This test covers the determination of total mercury in
3 that mercury concentrations are below those required for
natural gas at concentrations down to 1 ng/m . It includes
natural gas processing and operation.
separate procedures for both sampling and atomic absorption
spectrophotometric determination of mercury. The procedure 4.2 Adsorption of the mercury on gold-coated beads can
detects both inorganic and organic forms of mercury. remove interferences associated with the direct measurement
of mercury in natural gas. It preconcentrates the mercury
1.2 The values stated in SI units are to be regarded as the
before analysis thereby offering measurement of ultra-low
standard.
average concentrations in a natural gas stream over a long span
1.3 This standard does not purport to address all of the
of time. It avoids the cumbersome use of liquid spargers with
safety concerns, if any, associated with its use. It is the
on-site sampling, and eliminates contamination problems as-
responsibility of the user of this standard to establish appro- 3,4,5
sociated with the use of potassium permanganate solutions.
priate safety and health practices and determine the applica-
5. Apparatus
bility of regulatory limitations prior to use.
5.1 Atomic Absorption Spectrophotometer, equipped with a
2. Referenced Documents
10-cm-long path quartz absorption cell and a mercury source
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2.1 ASTM Standards:
lamp (EDLor other high intensity lamp). It must be capable of
D1193 Specification for Reagent Water
collecting and integrating data over a 30- to 60-s time window.
Background capabilities are strongly recommended.
3. Summary of Test Method
NOTE 1—Detection sensitivity may vary significantly depending on the
3.1 Mercury in a gas stream is adsorbed onto gold-coated
type of spectrophotometer and its accessories.
silica beads and subsequently directly desorbed by heat into a
5.2 Rotameter or Other Flow Measurement Device capable
long path-length quartz cell connected to an atomic absorption
of attaining and regulating air at approximately 500 mL/min.
spectrophotometer. Mercury atoms are detected by measuring
their absorbance of light from a mercury source lamp at a 5.3 Rotameter or Other Flow Measurement Device capable
of attaining and regulating the natural gas sample at approxi-
characteristic wavelength. The mercury concentration is ob-
tained from the absorbance peak area by comparison to mately 1000 to 2500 mL/min.
standards prepared at the time of analysis.
5.4 Dry or Wet Positive Displacement Test Meter, or other
calibrated total flow measurement device for measuring the
4. Significance and Use
volume of the sample.
4.1 This test method can be used to measure the level of
5.5 TFE-Fluorocarbon Tubing, to make connections to the
mercury in natural gas streams for purposes such as determin-
atomic absorption spectrophotometer. The size should be
ing compliance with regulations, studying the effect of various
appropriate for the quartz absorption cell.
1
5.6 Quartz Tubing, 12 cm long, ⁄4-in. outside diameter, to
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
be used for sorbent (gold-coated silica) packing.
Fuels and is the direct responsibility of Subcommittee D03.05 on Determination of
Special Constituents of Gaseous Fuels.
3
Current edition approved Dec. 1, 2006. Published February 2007. Originally Schroeder,W.H.,“SamplingandAnalysisofMercuryanditsCompoundsinthe
approved in 1996. Last previous edition approved 1998 as D5954–98. DOI: Atmosphere,” Environmental Science & Technology , 16, 1982, 394A–399A.
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10.1520/D5954-98R06. Chao, S.S., andAttari,A., “Characterization and Measurements of Natural Gas
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Trace Constituents—Volume II: Survey,” Final Report GRI-94/0243.2, June 1994.
5
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Braman, R.S., and Johnson, D.L., “Selective Absorption Tubes and Emission
Standards volume information, refer to the standard’s Document Summary page on Technique for the Determination of Ambient Forms of Mercury in Air,” Environ-
the ASTM website. mental Science & Technology, 8, 1974, pp. 996–1003.
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