ASTM D1945-14

Standard Test Method for Analysis of Natural Gas by Gas Chromatography

SIGNIFICANCE AND USE
4.1 This test method is of significance for providing data for calculating physical properties of the sample, such as heating value and relative density, or for monitoring the concentrations of one or more of the components in a mixture.
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 standard. No other units of measurement are included in this standard.  
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-Oct-2014
• ICS: 75.060 - Natural gas
• Technical Committee: D03 - 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D1945 − 14
Standard Test Method for
1
Analysis of Natural Gas by Gas Chromatography
This standard is issued under the fixed designation D1945; 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* composition of the sample is calculated by comparing either
the peak heights, or the peak areas, or both, with the corre-
1.1 This test method covers the determination of the chemi-
sponding values obtained with the reference standard.
cal composition of natural gases and similar gaseous mixtures
within the range of composition shown in Table 1. This test
4. Significance and Use
method may be abbreviated for the analysis of lean natural
4.1 This test method is of significance for providing data for
gases containing negligible amounts of hexanes and higher
calculating physical properties of the sample, such as heating
hydrocarbons, or for the determination of one or more
value and relative density, or for monitoring the concentrations
components, as required.
of one or more of the components in a mixture.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
5. Apparatus
standard.
5.1 Detector—The detector shall be a thermal-conductivity
1.3 This standard does not purport to address all of the
type, or its equivalent in sensitivity and stability. The thermal
safety concerns, if any, associated with its use. It is the
conductivity detector must be sufficiently sensitive to produce
responsibility of the user of this standard to establish appro-
a signal of at least 0.5 mV for 1 mol % n-butane in a 0.25-mL
priate safety and health practices and determine the applica-
sample.
bility of regulatory limitations prior to use.
5.2 Recording Instruments—Either strip-chart recorders or
electronicintegrators,orboth,areusedtodisplaytheseparated
2. Referenced Documents
components. Although a strip-chart recorder is not required
2
2.1 ASTM Standards:
when using electronic integration, it is highly desirable for
D2597 Test Method for Analysis of Demethanized Hydro-
evaluation of instrument performance.
carbon Liquid Mixtures Containing Nitrogen and Carbon
5.2.1 The recorder shall be a strip-chart recorder with a
Dioxide by Gas Chromatography
full-range scale of 5 mVor less (1 mVpreferred).The width of
E260 Practice for Packed Column Gas Chromatography
the chart shall be not less than 150 mm. A maximum pen
response time of2s(1s preferred) and a minimum chart speed
3. Summary of Test Method
of 10 mm/min shall be required. Faster speeds up to 100
3.1 Components in a representative sample are physically
mm/min are desirable if the chromatogram is to be interpreted
separated by gas chromatography (GC) and compared to
using manual methods to obtain areas.
calibration data obtained under identical operating conditions
5.2.2 Electronic or Computing Integrators—Proof of sepa-
from a reference standard mixture of known composition. The
ration and response equivalent to that for a recorder is required
numerous heavy-end components of a sample can be grouped
for displays other than by chart recorder. Baseline tracking
into irregular peaks by reversing the direction of the carrier gas
with tangent skim peak detection is recommended.
through the column at such time as to group the heavy ends
5.3 Attenuator—If the chromatogram is to be interpreted
eitherasC andheavier,C andheavier,orC andheavier.The
5 6 7
using manual methods, an attenuator must be used with the
detector output signal to maintain maximum peaks within the
recorder chart range.The attenuator must be accurate to within
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
0.5 % between the attenuator range steps.
Fuels and is the direct responsibility of Subcommittee D03.07 on Analysis of
Chemical Composition of Gaseous Fuels.
5.4 Sample Inlet System:
Current edition approved Nov. 1, 2014. Published November 2014. Originally
5.4.1 The sample inlet system shall be constructed of
approvedin1962.Lastpreviouseditionapprovedin2010asD1945-96(2010).DOI:
10.1520/D1945-14.
materials that are inert and nonadsorptive with respect to the
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
components in the sample. The preferred material of construc-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
tion is stainless steel. Copper, brass, and other copper-bearing
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. alloys are unacceptable. The sample inlet system from the
*A Summary of Changes section appear
...

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: D1945 − 03 (Reapproved 2010) D1945 − 14
Standard Test Method for
1
Analysis of Natural Gas by Gas Chromatography
This standard is issued under the fixed designation D1945; 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 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 inch-poundSI units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered No other units of measurement are included
in this standard.
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.
2. Referenced Documents
2
2.1 ASTM Standards:
D2597 Test Method for Analysis of Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by
Gas Chromatography
D3588 Practice for Calculating Heat Value, Compressibility Factor, and Relative Density of Gaseous Fuels
E260 Practice for Packed Column Gas Chromatography
3. Summary of Test Method
3.1 Components in a representative sample are physically separated by gas chromatography (GC) and compared to calibration
data obtained under identical operating conditions from a reference standard mixture of known composition. The numerous
heavy-end components of a sample can be grouped into irregular peaks by reversing the direction of the carrier gas through the
column at such time as to group the heavy ends either as C and heavier, C and heavier, or C and heavier. The composition of
5 6 7
the sample is calculated by comparing either the peak heights, or the peak areas, or both, with the corresponding values obtained
with the reference standard.
4. Significance and Use
4.1 This test method is of significance for providing data for calculating physical properties of the sample, such as heating value
and relative density, or for monitoring the concentrations of one or more of the components in a mixture.
5. Apparatus
5.1 Detector—The detector shall be a thermal-conductivity type, or its equivalent in sensitivity and stability. The thermal
conductivity detector must be sufficiently sensitive to produce a signal of at least 0.5 mV for 1 mol % n-butane in a 0.25-mL
sample.
5.2 Recording Instruments—Either strip-chart recorders or electronic integrators, or both, are used to display the separated
components. Although a strip-chart recorder is not required when using electronic integration, it is highly desirable for evaluation
of instrument performance.
1
This test method is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.07 on Analysis of Chemical
Composition of Gaseous Fuels.
Current edition approved Jan. 1, 2010Nov. 1, 2014. Published March 2010November 2014. Originally approved in 1962. Last previous edition approved in 20032010 as
D1945–96(2003).D1945-96(2010). DOI: 10.1520/D1945-03R10.10.1520/D1945-14.
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.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D1945 − 14
TABLE 1 Natural Gas Components and Range of
Composition Covered
Component Mol %
Helium 0.01 to 10
Hydrogen 0.01 to 10
Oxygen 0.01 to 20
Nitrogen 0.01 to 100
Carbon dioxide 0.01 to 20
Methane 0.01 to 100
Ethane 0.01 to 100
Hydrogen sulfide 0.3 to 30
Propane 0.01 to 100
Isobutane 0.01 to 10
n-Butane 0.01 to 10
Neopentane 0.01 to 2
Isopentane 0.01 to 2
n-Pentane
...