ASTM D3120-96

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
An American National Standard
Designation:D3120–96
Standard Test Method for
Trace Quantities of Sulfur in Light Liquid Petroleum
1
Hydrocarbons by Oxidative Microcoulometry
This standard is issued under the fixed designation D3120; 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 (ε) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3. Significance and Use
1.1 This test method covers the determination of sulfur in 3.1 This test method is used to determine trace quantities of
the range from 3.0 to 100 ppm (µg/g) in light liquid hydrocar- sulfur in reformer charge stocks and similar petroleum frac-
bons boiling in the range from 26 to 274°C (80 to 525°F). tions where such trace concentrations of sulfur are deleterious
1.2 This test method may be extended to liquid materials to the performance and life of the catalyst used in the process.
with higher sulfur concentrations by appropriate dilution. Higher concentrations of sulfur in products analyzed by this
1.3 The preferred units are micrograms per grams. Values test method after appropriate dilution are often detrimental to
stated in SI units are to be regarded as the standard. Values in the use of the product.
inch-pound units are for information only.
4. Interferences
1.4 This standard does not purport to address all of the
4.1 This test method is applicable in the presence of total
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- halideconcentrationsofupto10timesthesulfurlevelandtotal
nitrogen concentrations of up to 1000 times the sulfur level.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazard 4.2 This test method is not applicable in the presence of
total heavy metal concentrations (for example, Ni, V, Pb, etc.)
statements, see 6.3, 6.4, 6.8, and 6.10.
in excess of 500 µg/g (ppm).
2. Summary of Test Method
NOTE 1—To attain the quantitative detectability that the method is
2.1 A liquid sample is injected into a combustion tube
capable of, stringent techniques must be employed and all possible
maintained at about 800°C having a flowing stream of gas
sources of sulfur contamination must be eliminated.
containing about 80 % oxygen and 20 % inert gas (for
2
5. Apparatus
example, nitrogen, argon, etc.). Oxidative pyrolysis converts
thesulfurtosulfurdioxidewhichthenflowsintoatitrationcell
5.1 Pyrolysis Furnace—The sample should be pyrolyzed in
where it reacts with triiodide ion present in the electrolyte.The
an electric furnace having at least two separate and indepen-
triiodide thus consumed, is coulometrically replaced and the
dently controlled temperature zones, the first being an inlet
total current required to replace it is a measure of the sulfur
section that can maintain a temperature sufficient to volatilize
present in the sample injected.
all the organic sample. The second zone shall be a pyrolysis
2.2 The reaction occurring in the titration cell as sulfur
section that can maintain a temperature sufficient to pyrolyze
dioxide enters is:
theorganicmatrixandoxidizealltheorganicallyboundsulfur.
2 2 1 A third outlet temperature zone is optional.
I 1 SO 1 H O→ SO 13I 12H (1)
3 2 2 3
5.1.1 Pyrolysis furnace temperature zones for light liquid
The triiodide ion consumed in the above reaction is gener-
petroleum hydrocarbons should be variable as follows:
ated coulometrically thus:
Inlet zone up to at least 700°C
2 2 2
Center pyrolysis zone 800 to 1000°C
3I → I 12e (2)
3
Outlet zone (optional) up to at least 800°C
2.3 Thesemicroequivalentsoftriiodide(iodine)areequalto
the number of microequivalents of titratable sample ion enter-
ing the titration cell.
2
The apparatus described in Sections 5.1 to 5.5 inclusive, is similar in
1
This test method is under the jurisdiction of ASTM Committee D-2 on specifications to equipment available from Dohrmann Div. of Rosemount, 3240
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee Scott Blvd., Santa Clara, CA95050. For further detailed discussions, in equipment,
D02.03 on Elemental Analysis. see: Preprints—Division of Petroleum Chemistry,American Chemical Society, Vol
Current edition approved Apr. 10, 1996. Published June 1996. Originally 1, No. 3, Sept. 7–12, 1969, p. B232 “Determination of Sulfur, Nitrogen, and
published as D 3120–72T. Last previous edition D 3120–92. Chlorine in Petroleum by Microcoulometry,” by Harry V. Drushel.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West
...