ASTM D7493-08
(Test Method)Standard Test Method for Online Measurement of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatograph and Electrochemical Detection
Standard Test Method for Online Measurement of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatograph and Electrochemical Detection
SIGNIFICANCE AND USE
Gaseous fuels, such as natural gas, petroleum gases and bio-gases, contain varying amounts and types of sulfur compounds. These sulfur compounds are generally odorous, corrosive to equipment, and can inhibit or destroy catalysts employed in gas processing and end use, such as those used in fuel cell. Their accurate on-line measurement is essential to gas processing, operation and utilization, and of regulatory interest.
Small amounts (typically, total 4-6 PPMv) of sulfur odorants are added to natural gas and other fuel gases for safety purposes. Some sulfur odorants can be reactive, and may be oxidized, forming more stable sulfur compounds having lower odor thresholds. These gaseous fuels are analyzed for sulfur odorants to help in monitoring and to ensure appropriate odorant levels for public safety.
This method offers an on-line technique to continuously identify and quantify individual target sulfur species in gaseous fuel with automatic calibration and validation.
SCOPE
1.1 This test method is for on-line measurement of volatile sulfur-containing compounds in gaseous fuels by gas chromatography (GC) and electrochemical (EC) detection. The test method is applicable to hydrogen sulfide, C1-C4 mercaptans, sulfides and tetrahydrothiophene (THT).
1.1.1 Carbonyl sulfide (COS) is not covered in this test method.
1.1.2 The detection range for sulfur compounds is approximately from 0.1 to 100 PPMv or 0.1 to 100 mg/m3. The detection range may vary depending on the sample injection volume, chromatographic peak separation and the sensitivity of specific EC detector.
1.2 This test method describes a GC-EC method employing packed GC columns and a specific detector as an illustration for natural gas and other gaseous fuel containing mainly light hydrocarbons. Alternative GC columns, detector designs and instrument parameters may be used for the same analysis or for different types of gaseous fuel, provided that appropriate chromatographic separation and optimal detection of these compounds can be achieved.
1.3 This test method does not intend to identify and measure all individual sulfur species, and is mainly employed for monitoring natural sulfur and sulfur odorant compounds commonly found in fuel gases or employed as an odorous warning agent in fuel gases.
1.4 The test method is normally employed for repetitive on-line monitoring of sulfur components in fuel gases with a single sulfur standard. The test method may be employed for laboratory-quality measurement with more extensive calibration. (See Test Methods D 5504, D 5623, D 6228, D 6968, ISO 19739, ISO 6326-2, and GPA 2199.)
1.5 The test method can be used for measurement of all listed sulfur compounds in air or other gases, provided that no compound, which can interfere with the GC separation and electrochemical detection, is present.
1.6 This test method is written in conjunction with Practices D 5287, D 7165 and D 7166.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 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: D7493 − 08
StandardTest Method for
Online Measurement of Sulfur Compounds in Natural Gas
and Gaseous Fuels by Gas Chromatograph and
1
Electrochemical Detection
This standard is issued under the fixed designation D7493; 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 compound, which can interfere with the GC separation and
electrochemical detection, is present.
1.1 This test method is for on-line measurement of volatile
sulfur-containing compounds in gaseous fuels by gas chroma- 1.6 This test method is written in conjunction with Practices
tography (GC) and electrochemical (EC) detection. The test D5287, D7165 and D7166.
method is applicable to hydrogen sulfide, C1-C4 mercaptans,
1.7 The values stated in SI units are to be regarded as
sulfides and tetrahydrothiophene (THT).
standard. No other units of measurement are included in this
1.1.1 Carbonyl sulfide (COS) is not covered in this test
standard.
method.
1.8 This standard does not purport to address all of the
1.1.2 The detection range for sulfur compounds is approxi-
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safety concerns, if any, associated with its use. It is the
mately from 0.1 to 100 PPMv or 0.1 to 100 mg/m . The
responsibility of the user of this standard to establish appro-
detection range may vary depending on the sample injection
priate safety and health practices and determine the applica-
volume,chromatographicpeakseparationandthesensitivityof
bility of regulatory limitations prior to use.
specific EC detector.
1.2 This test method describes a GC-EC method employing 2. Referenced Documents
2
packed GC columns and a specific detector as an illustration
2.1 ASTM Standards:
for natural gas and other gaseous fuel containing mainly light
D3609 Practice for Calibration Techniques Using Perme-
hydrocarbons. Alternative GC columns, detector designs and
ation Tubes
instrumentparametersmaybeusedforthesameanalysisorfor
D4150 Terminology Relating to Gaseous Fuels
different types of gaseous fuel, provided that appropriate
D4626 Practice for Calculation of Gas Chromatographic
chromatographic separation and optimal detection of these
Response Factors
compounds can be achieved.
D5287 Practice for Automatic Sampling of Gaseous Fuels
1.3 Thistestmethoddoesnotintendtoidentifyandmeasure D5504 TestMethodforDeterminationofSulfurCompounds
all individual sulfur species, and is mainly employed for in Natural Gas and Gaseous Fuels by Gas Chromatogra-
phy and Chemiluminescence
monitoring natural sulfur and sulfur odorant compounds com-
monly found in fuel gases or employed as an odorous warning D5623 Test Method for Sulfur Compounds in Light Petro-
leum Liquids by Gas Chromatography and Sulfur Selec-
agent in fuel gases.
tive Detection
1.4 The test method is normally employed for repetitive
D6228 TestMethodforDeterminationofSulfurCompounds
on-line monitoring of sulfur components in fuel gases with a
in Natural Gas and Gaseous Fuels by Gas Chromatogra-
single sulfur standard. The test method may be employed for
phy and Flame Photometric Detection
laboratory-quality measurement with more extensive calibra-
D6968 Test Method for Simultaneous Measurement of Sul-
tion. (See Test Methods D5504, D5623, D6228, D6968, ISO
fur Compounds and Minor Hydrocarbons in Natural Gas
19739, ISO 6326-2, and GPA 2199.
and Gaseous Fuels by Gas Chromatography and Atomic
1.5 The test method can be used for measurement of all
Emission Detection
listed sulfur compounds in air or other gases, provided that no
D7165 Practice for Gas Chromatograph Based On-line/At-
line Analysis for Sulfur Content of Gaseous Fuels
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ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
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Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Analysis of Gaseous Fuels. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Dec. 15, 2008. Published January 2009. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D7493-08. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7493 − 08
D7166 Practice for Total SulfurAnalyzer Based On-line/At- rosive to equipment, and can inhibit or destroy catalysts
line for Sulfur Content of Gaseous Fuels employed in gas processing and end use, such as those used in
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fuelcell.Theiraccurateon-linemeasurementisessentialtogas
2.2 ISO Standards:
processing,operationandut
...
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