ASTM D6159-97(2002)
(Test Method)Standard Test Method for Determination of Hydrocarbon Impurities in Ethylene by Gas Chromatography
Standard Test Method for Determination of Hydrocarbon Impurities in Ethylene by Gas Chromatography
SIGNIFICANCE AND USE
High-purity ethylene is required as a feedstock for some manufacturing processes and the presence of trace amounts of certain hydrocarbon impurities can have deleterious effects. This test method is suitable for setting specifications, for use as an internal quality control tool, and for use in development or research work.
This test method does not detect such impurities as H2O, CO, CO2, and alcohols that may be present in the sample. Hydrocarbons higher than n-decane cannot be analyzed by this test method, if present in the sample. Test Method D 2504 addresses the analysis of noncondensable gases and Test Method D 2505 addresses the analysis of CO2. Guide D 5234 describes all potential impurities present in ethylene. These standards should be consulted when determining the total concentration of impurities in ethylene.
SCOPE
1.1 This test method is used for the determination of methane, ethane, propane, propene, acetylene, iso-butane, propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2-butene, methyl acetylene and 1,3-butadiene in high-purity ethylene. The purity of the ethylene can be calculated by subtracting the total percentage of all impurities from 100.00 %. Since this test method does not determine all possible impurities such as CO, CO2, H2O, alcohols, nitrogen oxides, and carbonyl sulfide, as well as hydrocarbons higher than decane, additional tests may be necessary to fully characterize the ethylene sample.
1.2 Data are reported in this test method as ppmV (parts per million by volume). This test method was evaluated in an interlaboratory cooperative study in the concentration range of 4 to 340 ppmV (2 to 204 mg/kg). The participants in the interlaboratory cooperative study reported the data in non-SI units. Wherever possible, SI units are included.
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.
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An American National Standard
Designation:D 6159–97 (Reapproved 2002)
Standard Test Method for
Determination of Hydrocarbon Impurities in Ethylene by Gas
Chromatography
This standard is issued under the fixed designation D 6159; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope A split-injector may or may not be used. The gas chromato-
graph is provided with a 6–port sampling valve and two wide
1.1 This test method is used for the determination of
bore capillary columns connected in series. These columns are
methane, ethane, propane, propene, acetylene, iso-butane,
a dimethyl silicone column and a (porous layer open tubular
propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2-
column (PLOT)Al O /KCl column. Aflame ionization detec-
2 3
butene, methyl acetylene and 1,3-butadiene in high-purity
tor is used for detection. The integrated detector signal (peak
ethylene. The purity of the ethylene can be calculated by
areas) are corrected for detector response. The hydrocarbon
subtracting the total percentage of all impurities from 100.00
impurities are determined and the total impurities are used to
%. Since this test method does not determine all possible
determine the ethylene content.
impurities such as CO, CO,H O, alcohols, nitrogen oxides,
2 2
and carbonyl sulfide, as well as hydrocarbons higher than
4. Significance and Use
decane, additional tests may be necessary to fully characterize
4.1 High-purity ethylene is required as a feedstock for some
the ethylene sample.
manufacturing processes and the presence of trace amounts of
1.2 Data are reported in this test method as ppmV (parts per
certain hydrocarbon impurities can have deleterious effects.
million by volume). This test method was evaluated in an
This test method is suitable for setting specifications, for use as
interlaboratory cooperative study in the concentration range of
an internal quality control tool, and for use in development or
4 to 340 ppmV (2 to 204 mg/kg). The participants in the
research work.
interlaboratory cooperative study reported the data in non-SI
4.2 ThistestmethoddoesnotdetectsuchimpuritiesasH O,
units. Wherever possible, SI units are included.
CO, CO , and alcohols that may be present in the sample.
1.3 This standard dose not purport to address all of the
Hydrocarbons higher than n-decane cannot be analyzed by this
safety concerns, if any, associated with its use. It is the
test method, if present in the sample. Test Method D 2504
responsibility of the user of this standard to establish appro-
addresses the analysis of noncondensable gases and Test
priate safety and health practices and determine the applica-
Method D 2505 addresses the analysis of CO . Guide D 5234
bility of regulatory limitations prior to use.
describes all potential impurities present in ethylene. These
2. Referenced Documents standards should be consulted when determining the total
concentration of impurities in ethylene.
2.1 ASTM Standards:
D 2504 Test Method for Noncondensable Gases in C and
5. Apparatus
Lighter Hydrocarbon Products by Gas Chromatography
5.1 Gas Chromatograph (GC), a gas chromatographic in-
D2505 TestMethodforEthylene,OtherHydrocarbons,and
strument provided with a temperature programmable column
Carbon Dioxide in High-Purity Ethylene by Gas Chroma-
2 ovenandaflameionizationdetector(FID).Regulatethecarrier
tography
3 gas by pressure control.
D 5234 Guide for Analysis of Ethylene Product
5.2 Detector—Use a flame ionization detector (FID) having
3. Summary of Test Method asensitivityofapproximately2.0ppmV(1.2mg/kg)orlessfor
the compounds listed in 1.1. An FID was exclusively used in
3.1 Agaseous ethylene sample is analyzed as received. The
the interlaboratory cooperative study.
gaseous sample is injected into a capillary gas chromatograph.
5.3 Column Temperature Programmer—The chromato-
graph shall be capable of linear programmed temperature
This test method is under the jurisdiction of ASTM Committee D02 on operation over a range sufficient for separation of the compo-
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
nents of interest. Section 8 lists the recommended operating
D02.D0 on Hydrocarbons for Chemical and Special Uses.
Current edition approved Dec. 10, 2002. Published March 2003. Originally
approved in 1997. Last previous edition approved in 1997 as D 6159 – 97.
Annual Book of ASTM Standards, Vol 05.01.
3 4
Annual Book of ASTM Standards, Vol 05.02. This column is supplied by major column manufacturers.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6159–97 (2002)
conditions. The programming rate shall be sufficiently repro-
ducible to obtain retention repeatability of 0.05 min (3 s)
throughout the scope of this analysis.
5.4 Columns—Couple the two columns in series with either
aglasspresstightconnectororamini-connectorequippedwith
graphite ferrules.
5.4.1 Column 1, 50 m, 0.53 mm inside diameter (ID) KCl
deactivatedAl O PLOT column. Relative retention is depen-
2 3
dent on the deactivation method of the column. Other deacti-
vated Al O plot columns using sulfates as the deactivating
2 3
agent were also used in the interlaboratory comparison.
5.4.2 Column 2, 30 m, 0.53 mm ID, 5µm film thickness
methyl silicone. This column improves the separation of
FIG. 2 Valve On – Injection
methyl acetylene, iso-pentane, and n-pentane.
5.5 Sample Inlet System—Two injection modes were used
for the interlaboratory cooperative study.
5.5.1 A gas sampling valve placed in an unheated zone of
the gas chromatograph injecting the sample directly into the
column.
5.5.2 A gas sampling valve placed in an unheated zone of
the gas chromatograph in conjunction with a splitter injector
heated with a variable temperature control.
5.6 Gas Sampling Valve and Injection System—Use a 6-port
valve provided with ⁄16 in. fittings as the sample injection
system.AtypicalvalvearrangementisshowninFig.1andFig.
2. Use a 10–60µL loop as shown in Fig. 1. Use good valve
maintenance techniques to avoid such problems as dead
FIG. 3 Valve Off – Sample Loading
volumes,coldspots,longconnections,andnon-uniformheated
zones. The preferred carrier gas arrangement for sample
introduction is pressure regulation. Use a 6-port valve in
conjunction with a splitter injector. A typical arrangement is
shown in Fig. 3 and Fig. 4. Use split ratios of 50:1 to 100:1 at
temperatures of 150°C to 200°C. Loop sizes of 200–500µL
were used in the interlaboratory study. When using a splitter it
isimportanttochecklinearityofthesplitter.Injectthestandard
blend at 50:1, 75:1, and 100:1 split ratios. Check the response
factorsasdeterminedin9.1,andthefactorsshallnotvarymore
than 3 %.
5.7 Data Acquisition System—Use any integrator or com-
puterized data acquisition system for peak area integration, as
well as for recording the chromatographic trace.
FIG. 4 Valve On – Injection
6. Reagent Materials
6.1 Standard Mixture—Use a gravimetrically blended gas
standard containing levels of 2 to 204 mg/kg (4 to 340 ppmV)
of each of the trace components listed in Table 1 to calibrate
the detector’s response. The standard gas mixture shall be
prepared gravimetrically from known raw materials, and cross
contaminants shall be taken into account. The mixtures should
be certified analytically such that the gravimetric and analyti-
cally derived values agree to an acceptable tolerance; that is 6
1or 6 2 %. The concentration of the minor components in the
calibration standard shall be within 20 to 50 % above the
FIG. 1 Valve Off – Sample Loading concentration of the process stream or samples.
D 6159–97 (2002)
TABLE 1 Typical Compounds and Retention Times for Common
Injection System with Splitter
A
Hydrocarbon Impurities in Ethylene
Sample valve loop volume = 200–500µl
Components Retention Time, min
Sample valve temperature = 35° to 45°C
Methane 7.02
Splitter tempera
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