ASTM D7620-10(2020)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7620 − 10 (Reapproved 2020)
Standard Test Method for
Determination of Total Sulfur in Liquid Hydrocarbon Based
Fuels by Continuous Injection, Air Oxidation and Ultraviolet
Fluorescence Detection
This standard is issued under the fixed designation D7620; 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 D1298 Test Method for Density, Relative Density, or API
Gravity of Crude Petroleum and Liquid Petroleum Prod-
1.1 This test method covers the determination of total sulfur
ucts by Hydrometer Method
inliquidhydrocarbonbasedfuelwithafinalboilingpointofup
D4052 Test Method for Density, Relative Density, and API
to 450 °C. It is applicable to analysis of natural, processed and
Gravity of Liquids by Digital Density Meter
final product materials containing sulfur in the range of
D4057 Practice for Manual Sampling of Petroleum and
4.0 mg⁄kg to 830 mg⁄kg (see Note 1).
Petroleum Products
NOTE 1—For liquid hydrocarbons containing less than 4.0 mg⁄kg total
D4175 Terminology Relating to Petroleum Products, Liquid
sulfur or more than 830 mg⁄kg total sulfur, Test Method D5453 may be
Fuels, and Lubricants
more appropriate.
D4177 Practice for Automatic Sampling of Petroleum and
1.2 This test method is applicable for total sulfur determi-
Petroleum Products
nation in liquid hydrocarbons containing less than 0.35 %
D5453 Test Method for Determination of Total Sulfur in
(m⁄m) halogen(s).
Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel
Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this D6299 Practice for Applying Statistical Quality Assurance
and Control Charting Techniques to Evaluate Analytical
standard.
Measurement System Performance
1.4 This standard does not purport to address all of the
D6300 Practice for Determination of Precision and Bias
safety concerns, if any, associated with its use. It is the
Data for Use in Test Methods for Petroleum Products,
responsibility of the user of this standard to establish appro-
Liquid Fuels, and Lubricants
priate safety, health, and environmental practices and deter-
D6792 Practice for Quality Management Systems in Petro-
mine the applicability of regulatory limitations prior to use.
leum Products, Liquid Fuels, and Lubricants Testing
For specific hazard statements, see 4.1, 8.3, and Section 9.
Laboratories
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 3.1 Definitions:
3.1.1 See Terminology D4175 for definitions of other terms
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. used in this test method.
3.1.2 oxidative pyrolysis, n—process in which a sample
2. Referenced Documents
undergoes complete combustion in an appropriate oxygen
containing environment at a sufficiently elevated temperature.
2.1 ASTM Standards:
3.1.2.1 Discussion—Organic compounds pyrolytically oxi-
dize to carbon dioxide and water and oxides of other elements
1 that are in the sample.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.03 on Elemental Analysis.
4. Summary of Test Method
Current edition approved May 1, 2020. Published June 2020. Originally
4.1 A small, very controlled flow of hydrocarbon sample is
approved in 2010. Last previous edition approved in 2015 as D7620 – 10 (2015).
DOI:10.1520/D7620-10R20.
continuously injected during measurement. It is introduced via
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
a syringe into a high temperature combustion tube containing
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
air where sulfur is oxidized to sulfur dioxide (SO ). Water
Standards volume information, refer to the standard’s Document Summary page on 2
the ASTM website. produced during the sample combustion is removed, as
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7620 − 10 (2020)
FIG. 1 Basic Block Diagram Describing Sulfur Determination
required, and the sample combustion gases are next exposed to
ultraviolet (UV) light. The SO absorbs the energy from the
UV light and is converted to excited sulfur dioxide (SO *).
Fluorescence emitted from the excited SO * as it returns to a
stable state SO is detected by a photomultiplier tube and the
resulting signal is a measure of the sulfur contained in the
sample. (Warning—Exposure to excessive quantities of ultra-
violet light is injurious to health. The operator shall avoid
exposing their body, especially their eyes, not only to direct
UV light but also to secondary or scattered radiation that is
present.)
4.2 Fig. 1 illustrates a basic block diagram describing sulfur
determination. Sample collection and conditioning, sample
introduction, detection system and data handling are depicted.
5. Significance and Use
5.1 Some process catalysts used in refining can be poisoned
whentraceamountsofsulfurbearingmaterialsarecontainedin
the feedstocks. There are also government regulations as to
how much sulfur is permitted to be present in commercial
transportation fuels. This test method can be used to determine
sulfur in process and downstream distribution streams. It can
also be used for purposes of screening and quality control of
finished hydrocarbon fuel products.
6. Interferences
6.1 Halogens above 0.35 % (mass/mass) will interfere with
accurate sulfur determination.
6.2 Bound nitrogen at concentration greater than 150 mg
N/kg can cause a 1 mg S/kg positive bias.
6.3 Excessive moisture produced during the combustion
step will interfere if not removed prior to the detector.
7. Apparatus
7.1 Furnace—An electric furnace held at a temperature
sufficient to pyrolyze the entire sample (typically 1050 °C 6
25 °C) and oxidize sulfur to SO .
7.2 Combustion Tube—A quartz combustion tube con-
structed to allow the direct injection of a continuous flow of
FIG. 2 Typical Combustion Tube
sample into the heated oxidation zone of the furnace. The
oxidation section shall be large enough to ensure complete
combustion of the sample. Fig. 2 illustrates a typical combus-
7.4 Drier Tube—The apparatus shall be equipped with a
tion tube (Note 2).
mechanism for the removal of excessive water vapor. The
NOTE 2—Other combustion tube configurations are acceptable if
oxidation reaction produces water vapor which must be elimi-
precision and accuracy are not degraded.
nated prior to measurement by the detector. This may be
7.3 Flow Control—The apparatus shall be equipped with accomplished with a membrane drying tube, or a permeation
suitable flow control apparatus capable of maintaining a dryer, that utilizes a selective capillary action for water
constant supply of air. removal.
D7620 − 10 (2020)
TABLE 1 Typical Operating Conditions
7.5 UV Fluorescence Detector—A quantitative detector ca-
pableofmeasuringtheenergyemittedfromthefluorescenceof Furnace Temperature 1050 °C
Furnace Pressure 28 kPa
sulfur dioxide by UV light.
Photo Multiplier Tube (PMT) 40 °C
Temperature
7.6 Millilitre Syringe—A disposable 1 mL syringe capable
PMT Voltage 900 V
of accurately delivering a controlled and constant flow of
Optics Purge Flow 80 mL ⁄min to 100 mL ⁄min
calibration and sample materials. The syringe shall accommo-
date a disposable tip to aid the filling of the syringe and a
disposable septum seal to accommodate penetration and
9. Hazards
sample flow.
9.1 Consult current OSHA regulations, suppliers’ Material
7.7 Sample Inlet System—An automatic sample injection
Safety Data Sheets, and local regulations for all materials used
device that is compatible with a disposable 1 mL syringe is
in this test method.
required. The injector shall allow the introduction of an
9.2 High temperature is employed in this test method.
appropriate continuous flow of sample into a combustion tube
Exercise extra care when using flammable materials near the
carrierstream,whichdirectsthesampleintotheoxidationzone
oxidative pyrolysis furnace.
at a controlled and repeatable rate.
9.3 Duetothetypesofsamplesanalyzedinthistestmethod,
7.8 Strip Chart Recorder—Equivalent electronic data
chemicalresistantglovesshouldbewornwhenperformingthis
logger, integrator or recorder (optional).
test method.
7.9 Balance—With a precision of 60.01 mg (optional).
10. Sampling
8. Reagents and Materials
10.1 CollectthesamplesinaccordancewithPracticeD4057
8.1 Purity of Reagents—Reagent grade chemicals shall be
or Practice D4177. To preserve volatile components which are
used in tests. Unless otherwise indicated, it is intended that all
in some samples, do not uncover samples any longer than
reagents shall conform to the specifications of the Committee
necessary.
on Analytical Reagents of the American Chemical Society,
where such specifications are available. Other grades may be
11. Preparation of Apparatus
used, provided, it is first ascertained that the reagent is of
11.1 Place the analyzer in service in accordance with the
sufficiently high purity to permit its use without lessening the
manufacturer’s instructions.
accuracy of the determination.
11.2 Typical instrument parameters are listed in Table 1.
8.2 Air—Filtered (with a 2 µm filter).
11.3 Prepare the sample introduction accessories, if
8.3 Iso-octane, Toluene, Xylenes—Reagent grade.
required, according to the manufacturer’s instructions.
(Warning—Organic solvents are flammable.)
11.4 Adjust the instrument sensitivity and baseline stability
8.4 Thiophene—FW84.14, Sulfur content 38.10 % (m/m).
and perform instrument blanking procedure following manu-
8.4.1 Other sources of sulfur and diluent materials may be
facturer’s guidelines.
used if precision and accuracy are not degraded.
8.4.2 Apply the appropriate correction for chemical impu-
12. Calibration
rity.
12.1 Choose which type of calibration method is required
8.5 Sulfur Stock Solution—1000 µg S/mL. Prepare a stock
(mass/volume or mass/mass), and prepare a calibratio
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