ASTM D1945-96e1

Standard Test Method for Analysis of Natural Gas by Gas Chromatography

SCOPE
1.1 This test method covers the determination of the chemical composition of natural gases and similar gaseous mixtures within the range of composition shown in Table 1. This test method may be abbreviated for the analysis of lean natural gases containing negligible amounts of hexanes and higher hydrocarbons, or for the determination of one or more components, as required.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 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.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• Technical Committee: D03 - Gaseous Fuels

Relations

• Replaced By: ASTM D1945-96(2001) - Standard Test Method for Analysis of Natural Gas by Gas Chromatography
• Effective Date: 01-Jan-2001

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
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Designation: D 1945 – 96
Standard Test Method for
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Analysis of Natural Gas by Gas Chromatography
This standard is issued under the fixed designation D 1945; 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 (ε) indicates an editorial change since the last revision or reapproval.
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ε NOTE—Footnote 5 has been editorially updated in January 2001.
TABLE 1 Natural Gas Components and Range of
1. Scope
Composition Covered
1.1 This test method covers the determination of the chemi-
Component Mol%
cal composition of natural gases and similar gaseous mixtures
Helium 0.01 to 10
within the range of composition shown in Table 1. This test
Hydrogen 0.01 to 10
method may be abbreviated for the analysis of lean natural
Oxygen 0.01 to 20
gases containing negligible amounts of hexanes and higher Nitrogen 0.01 to 100
Carbon dioxide 0.01 to 20
hydrocarbons, or for the determination of one or more compo-
Methane 0.01 to 100
nents, as required.
Ethane 0.01 to 100
Hydrogen sulfide 0.3 to 30
1.2 The values stated in SI units are to be regarded as the
Propane 0.01 to 100
standard. The values given in parentheses are for information
Isobutane 0.01 to 10
only.
n-Butane 0.01 to 10
Neopentane 0.01 to 2
1.3 This standard does not purport to address all of the
Isopentane 0.01 to 2
safety concerns, if any, associated with its use. It is the
n-Pentane 0.01 to 2
responsibility of the user of this standard to establish appro-
Hexane isomers 0.01 to 2
Heptanes+ 0.01 to 1
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2. Referenced Documents
through the column at such time as to group the heavy ends
2.1 ASTM Standards: eitherasC andheavier,C andheavier,orC andheavier.The
5 6 7
composition of the sample is calculated by comparing either
D 2597 Test Method for Analysis of Demethanized Hydro-
carbon Liquid Mixtures Containing Nitrogen and Carbon the peak heights, or the peak areas, or both, with the corre-
2
Dioxide by Gas Chromatography sponding values obtained with the reference standard.
D 3588 Practice for Calculating Heat Value, Compressibil-
4. Significance and Use
ity Factor, and Relative Density (Specific Gravity) of
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4.1 This test method is of significance for providing data for
Gaseous Fuels
4
E 260 Practice for Packed Column Gas Chromatography calculating physical properties of the sample, such as heating
value and relative density, or for monitoring the concentrations
3. Summary of Test Method
of one or more of the components in a mixture.
3.1 Components in a representative sample are physically
5. Apparatus
separated by gas chromatography (GC) and compared to
5.1 Detector—The detector shall be a thermal-conductivity
calibration data obtained under identical operating conditions
type, or its equivalent in sensitivity and stability. The thermal
from a reference standard mixture of known composition. The
conductivity detector must be sufficiently sensitive to produce
numerous heavy-end components of a sample can be grouped
a signal of at least 0.5 mV for 1 mol % n-butane in a 0.25-mL
into irregular peaks by reversing the direction of the carrier gas
sample.
5.2 Recording Instruments—Either strip-chart recorders or
electronic integrators, or both, are used to display the separated
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This test method is under the jurisdiction ofASTM Committee D-3 on Gaseous
components. Although a strip-chart recorder is not required
Fuels and is the direct responsibility of Subcommittee D03.07 on Analysis of
when using electronic integration, it is highly desirable for
Chemical Composition of Gaseous Fuels.
Current edition approved Nov. 10, 1996. Published January 1997. Originally
evaluation of instrument performance.
published as D 1945 – 62 T. Last previous edition D 1945 – 91.
5.2.1 The recorder shall be a strip-chart recorder with a
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Annual Book of ASTM Standards, Vol 05.02.
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full-range scale of 5 mVor less (1 mVpreferred).The width of
Annual Book of ASTM Standards, Vol 05.05.
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Annual Book of ASTM Standards, Vol 14.02. the chart shall be not less than 150 mm. A maximum pen
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D1945–96
response time of2s(1s preferred) and a minimum chart speed 5.5.1 Isothermal—When isothermal operation is used,
of 10 mm/min shall be required. Faster speeds up to 100 maintain the analyzer columns at a temperature constant to
mm/min are desirable if the chromatogram is to be interpreted 0.3°C during the course of the sample run and corresponding
using manual methods to obtain areas. reference run.
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