Standard Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry

SIGNIFICANCE AND USE
Trace quantities of sulfur compounds in hydrocarbon products can be harmful to many catalytic chemical processes in which these products are used. Maximum permissible levels of total sulfur are normally included in specifications for such hydrocarbons. It is recommended that this test method be used to provide a basis for agreement between two laboratories when the determination of sulfur in hydrocarbon gases is important.
On liquefied petroleum gas, total volatile sulfur is measured on an injected gas sample. For such material a liquid sample must be used to measure total sulfur.
SCOPE
1.1 This test method covers determination of sulfur in the range from 1.5 to 100 mg/kg (ppm by mass) by weight in hydrocarbon products that are gaseous at normal room temperature and pressure.
Note 1— The test method has been tested cooperatively only on high-purity ethylene gas. Precision data have not been developed for other products.
1.2 The values stated in Si units are to be regarded as the standard. The values given n parentheses are for information only
1.3This 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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Historical
Publication Date
30-Apr-2005
Current Stage
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ASTM D3246-05 - Standard Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3246–05
Standard Test Method for
1
Sulfur in Petroleum Gas by Oxidative Microcoulometry
This standard is issued under the fixed designation D3246; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* Compressed Gas Association Booklets G-4 and G-4-1 on
3
the Use of Oxygen
1.1 This test method covers determination of sulfur in the
range from 1.5 to 100 mg/kg (ppm by mass) by weight in
3. Summary of Test Method
hydrocarbon products that are gaseous at normal room tem-
3.1 Asample is injected into a combustion tube maintained
perature and pressure.
at about 800°C having a flowing stream of gas containing
NOTE 1—The test method has been tested cooperatively only on
about 80% oxygen and 20% inert gas (for example, nitrogen,
high-purityethylenegas.Precisiondatahavenotbeendevelopedforother
argon, etc.). Oxidative pyrolysis converts the sulfur to sulfur
products.
dioxide which then flows into a titration cell where it reacts
1.2 The values stated in SI units are to be regarded as
with triiodide ion present in the electrolyte. The triiodide thus
standard. No other units of measurement are included in this
consumed, is coulometrically replaced and the total current
standard.
required to replace it is a measure of the sulfur present in the
1.3 This standard does not purport to address all of the
sample injected.
safety concerns, if any, associated with its use. It is the
3.2 The reaction occurring in the titration cell as sulfur
responsibility of the user of this standard to establish appro-
dioxide enters is:
priate safety and health practices and determine the applica-
2 2 1
I 1 SO 1H O→SO 13I 12H (1)
3 2 2 3
bility of regulatory limitations prior to use.
The triiodide ion consumed in the above reaction is gener-
2. Referenced Documents
ated coulometrically thus:
2
2.1 ASTM Standards:
2 2 2
3I →I 12e (2)
3
D1265 Practice for Sampling Liquefied Petroleum (LP)
3.3 Thesemicroequivalentsoftriiodide(iodine)areequalto
Gases, Manual Method
the number of microequivalents of titratable sample ion enter-
D1193 Specification for Reagent Water
ing the titration cell.
D3120 Test Method for Trace Quantities of Sulfur in Light
3.4 A liquid blend containing a known amount of sulfur is
Liquid Petroleum Hydrocarbons by Oxidative Microcou-
used for calibration.
lometry
D6299 Practice for Applying Statistical Quality Assurance
4. Significance and Use
and Control Charting Techniques to Evaluate Analytical
4.1 Trace quantities of sulfur compounds in hydrocarbon
Measurement System Performance
products can be harmful to many catalytic chemical processes
F307 Practice for Sampling Pressurized Gas for GasAnaly-
inwhichtheseproductsareused.Maximumpermissiblelevels
sis
of total sulfur are normally included in specifications for such
2.2 Other Standards:
hydrocarbons. It is recommended that this test method be used
to provide a basis for agreement between two laboratories
1
This test method is under the jurisdiction of ASTM Committee D02 on
when the determination of sulfur in hydrocarbon gases is
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
important.
D02.03 on Elemental Analysis.
4.2 On liquefied petroleum gas, total volatile sulfur is
Current edition approved May 1, 2005. Published May 2005. Originally
measuredonaninjectedgassample.Forsuchmaterialaliquid
approved in 1973. Last previous edition approved in 1996 as D3246–96. DOI:
10.1520/D3246-05.
sample must be used to measure total sulfur.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available from Compressed Gas Association, 1235 Jefferson Davis Hwy.,
the ASTM website. Arlington, VA 22202.
*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.
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D3246–05
5. Interferences reference electrode pair, and comparing this potential with a
biaspotential,amplifyingthepotentialdifference,andapplying
5.1 This test method is applicable in the presence of total
theamplifieddifferencetotheworking-auxiliaryelectrodepair
halideconcentrationsofupto10timesthesulfurlevelandtotal
so as to generate a titrant. Also the microcoulometer output
nitrogen content of up to 1.0%. Free nitrogen does not
voltage signal shall be proportional to the generating current.
interfere.
6.5 Recorder,havingasensit
...

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