ASTM D7493-14(2018)

Standard Test Method for Online Measurement of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatograph and Electrochemical Detection

SIGNIFICANCE AND USE
5.1 Gaseous fuels, such as natural gas, petroleum gases and bio-gases, contain sulfur compounds that are naturally occurring or that are added as odorants for safety purposes. These sulfur compounds are odorous, corrosive to equipment, and can inhibit or destroy catalysts employed in gas processing and other end uses. Their accurate continuous measurement is important to gas processing, operation and utilization, and is frequently of regulatory interest.  
5.2 Small amounts (typically, total of 4 to 6 ppmv) of sulfur odorants are added to natural gas and other fuel gases for safety purposes. Some sulfur odorants are reactive, and may be oxidized to form more stable sulfur compounds having lower odor thresholds which adversely impact the potential safety of the gas delivery systems and gas users. Gaseous fuels are analyzed for sulfur compounds and odorant levels to assist in pipeline integrity surveillance and to ensure appropriate odorant levels for public safety.  
5.3 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. This test method is applicable to hydrogen sulfide, C1 to 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 (mL/m3) or 0.1 to 100 mg/m3. The detection range may vary depending on the sample injection volume, chromatographic peak separation and the sensitivity to the specific EC detector.  
1.2 This test method describes a GC-EC method employing packed GC columns and a specific detector for natural gas and other gaseous fuel composed of mainly light (C4 and smaller) hydrocarbons. Alternative GC columns, detector designs and instrument parameters may be used, provided that chromatographic separation, quality control and measurement objectives needed to comply with user, or regulator needs or both, are achieved.  
1.3 This test method does not intend to identify and measure all individual sulfur species, and is mainly employed for monitoring naturally occurring reduced sulfur compounds commonly found in natural gas and fuel gases or employed as an odorant in these gases.  
1.4 The test method is typically employed in repetitive or continuous on-line monitoring of sulfur components in natural gas and fuel gases using a single sulfur calibration standard. Need for a multipoint calibration curve or quality control procedures can be satisfied by making use of procedures delineated in Test Methods D5504, D5623, D6228, D6968, ISO 19739, or GPA 2199.  
1.5 The test method can be used for measurement of all sulfur compounds listed in Table 1 in air or other gaseous matrices, provided that no compounds that can interfere with the GC separation and electrochemical detection are present.  
1.6 This test method is written as a companion to Practices D5287, D7165 and D7166.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 30-Jun-2018
• ICS: 75.160.30 - Gaseous fuels
• Technical Committee: D03 - Gaseous Fuels
• Drafting Committee: D03.12 - On-Line/At-Line Analysis of Gaseous Fuels

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7493 − 14 (Reapproved 2018)
Standard Test 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 1.5 The test method can be used for measurement of all
sulfur compounds listed in Table 1 in air or other gaseous
1.1 This test method is for on-line measurement of volatile
matrices, provided that no compounds that can interfere with
sulfur-containing compounds in gaseous fuels by gas chroma-
the GC separation and electrochemical detection are present.
tography (GC) and electrochemical (EC) detection. This test
method is applicable to hydrogen sulfide, C1 to C4 mercaptans, 1.6 This test method is written as a companion to Practices
sulfides and tetrahydrothiophene (THT). D5287, D7165 and D7166.
1.1.1 Carbonyl sulfide (COS) is not covered in this test
1.7 The values stated in SI units are to be regarded as
method.
standard. No other units of measurement are included in this
1.1.2 The detection range for sulfur compounds is approxi-
standard.
3 3
mately from 0.1 to 100 ppmv (mL/m ) or 0.1 to 100 mg/m .
1.8 This standard does not purport to address all of the
The detection range may vary depending on the sample
safety concerns, if any, associated with its use. It is the
injection volume, chromatographic peak separation and the
responsibility of the user of this standard to establish appro-
sensitivity to the specific EC detector.
priate safety, health, and environmental practices and deter-
1.2 This test method describes a GC-EC method employing
mine the applicability of regulatory limitations prior to use.
packed GC columns and a specific detector for natural gas and
1.9 This international standard was developed in accor-
other gaseous fuel composed of mainly light (C4 and smaller)
dance with internationally recognized principles on standard-
hydrocarbons. Alternative GC columns, detector designs and
ization established in the Decision on Principles for the
instrument parameters may be used, provided that chromato-
Development of International Standards, Guides and Recom-
graphic separation, quality control and measurement objectives
mendations issued by the World Trade Organization Technical
needed to comply with user, or regulator needs or both, are
Barriers to Trade (TBT) Committee.
achieved.
1.3 This test method does not intend to identify and measure
2. Referenced Documents
all individual sulfur species, and is mainly employed for
2
2.1 ASTM Standards:
monitoring naturally occurring reduced sulfur compounds
D3609 Practice for Calibration Techniques Using Perme-
commonly found in natural gas and fuel gases or employed as
ation Tubes
an odorant in these gases.
D4150 Terminology Relating to Gaseous Fuels
1.4 The test method is typically employed in repetitive or
D4626 Practice for Calculation of Gas Chromatographic
continuous on-line monitoring of sulfur components in natural
Response Factors
gas and fuel gases using a single sulfur calibration standard.
D5287 Practice for Automatic Sampling of Gaseous Fuels
Need for a multipoint calibration curve or quality control
D5504 Test Method for Determination of Sulfur Compounds
procedures can be satisfied by making use of procedures
in Natural Gas and Gaseous Fuels by Gas Chromatogra-
delineated in Test Methods D5504, D5623, D6228, D6968,
phy and Chemiluminescence
ISO 19739, or GPA 2199.
D5623 Test Method for Sulfur Compounds in Light Petro-
leum Liquids by Gas Chromatography and Sulfur Selec-
tive Detection
1
This test method is under the jurisdiction of ASTM Committee D03 on Gaseous
Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line
2
Analysis of Gaseous Fuels. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2018. Published July 2018. Originally approved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 2008. Last previous edition approved in 2014 as D7493-14. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D7493-14R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7493 − 14 (2018)
TABLE 1 Typical Retention Times of Sulfur Components of Different GC-ECD Runs
GC-EC instrument GC-EC #1 GC-EC #2 GC-EC #3
1
GC-Column and ⁄8 in. ID× 70 cm L, 1.6 mm ID
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7493 − 14 D7493 − 14 (Reapproved 2018)
Standard Test 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
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. This test method is applicable to hydrogen sulfide, C1 to C4
mercaptans, sulfides and tetrahydrothiophene (THT).
1.1.1 Carbonyl sulfide (COS) is not covered in this test method.
3 3
1.1.2 The detection range for sulfur compounds is approximately from 0.1 to 100 ppmv (mL/m ) or 0.1 to 100 mg/m . The
detection range may vary depending on the sample injection volume, chromatographic peak separation and the sensitivity to the
specific EC detector.
1.2 This test method describes a GC-EC method employing packed GC columns and a specific detector for natural gas and other
gaseous fuel composed of mainly light (C4 and smaller) hydrocarbons. Alternative GC columns, detector designs and instrument
parameters may be used, provided that chromatographic separation, quality control and measurement objectives needed to comply
with user, or regulator needs or both, are achieved.
1.3 This test method does not intend to identify and measure all individual sulfur species, and is mainly employed for
monitoring naturally occurring reduced sulfur compounds commonly found in natural gas and fuel gases or employed as an odorant
in these gases.
1.4 The test method is typically employed in repetitive or continuous on-line monitoring of sulfur components in natural gas
and fuel gases using a single sulfur calibration standard. Need for a multipoint calibration curve or quality control procedures can
be satisfied by making use of procedures delineated in Test Methods D5504, D5623, D6228, D6968, ISO 19739, or GPA 2199.
1.5 The test method can be used for measurement of all sulfur compounds listed in Table 1 in air or other gaseous matrices,
provided that no compounds that can interfere with the GC separation and electrochemical detection are present.
1.6 This test method is written as a companion to Practices D5287, D7165 and D7166.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D3609 Practice for Calibration Techniques Using Permeation Tubes
D4150 Terminology Relating to Gaseous Fuels
1
This test method is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line
Analysis of Gaseous Fuels.
Current edition approved June 1, 2014July 1, 2018. Published July 2014July 2018. Originally approved in 2008. Last previous edition approved in 2014 as D7493-08.-14.
DOI: 10.1520/D7493-14.10.1520/D7493-14R18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7493 − 14 (2018)
TABLE 1 Typical Retention Times of Sulfur Components of Different GC-ECD Runs
GC-EC instrument GC-EC #1 GC-EC #2 GC-EC #3
1
GC-Column and ⁄8 in. ID× 70 cm L, 1.6 mm ID× 1200 mm L, 4 mm ID× 400 mm L,
parameters N , 12 mL/min, 65 °C N
...