ASTM D7679-16(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: D7679 − 16 (Reapproved 2020)
Standard Test Method for
Sulfur Content in Carbon Black Feedstock Oils
This standard is issued under the fixed designation D7679; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the instrumental determination
D1619 Test Methods for Carbon Black—Sulfur Content
of sulfur content in samples of carbon black feedstock oils.
D4057 Practice for Manual Sampling of Petroleum and
Values obtained represent the total sulfur content.Two analysis
Petroleum Products
methods are available for use:
D4177 Practice for Automatic Sampling of Petroleum and
Test Method A: High-Temperature Combustion Sections4–10
Petroleum Products
With
Infrared Absorption Detection Procedures
D4483 Practice for Evaluating Precision for Test Method
Test Method B: X-Ray Fluorescence Sections13–17
Standards in the Rubber and Carbon Black Manufacturing
1.2 This test method is applicable to carbon black feedstock Industries
oils derived from petroleum, coal, and other sources which
3. Significance and Use
include fuel oils, residues, tars, pitches, reclaimed oils, and
similar materials that are normally handled as liquids. This test
3.1 Measuring the total sulfur content of feedstock oil is
method is applicable to products typically containing 0 to 5
often a necessary component in calculations for sulfur dioxide
mass % sulfur.
emissions.
1.3 The results of these tests can be expressed as mass %
3.2 The carbon black industry measures sulfur content of
sulfur.
feedstock oils along with sulfur content of carbon black
products per Test Method D1619 in calculations to determine
1.4 The values stated in SI units are to be regarded as
sulfur dioxide emissions for compliance with governmental
standard. No other units of measurement are included in this
reporting requirements.
standard.
TEST METHOD A: HIGH-TEMPERATURE
1.5 This standard does not purport to address all of the
COMBUSTION WITH INFRARED ABSORPTION
safety concerns, if any, associated with its use. It is the
DETECTION PROCEDURES
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
mine the applicability of regulatory limitations prior to use.
4.1 In this test method, a sample of feedstock oil is weighed
1.6 This international standard was developed in accor-
in a combustion boat containing either a tungsten oxide based
dance with internationally recognized principles on standard-
accelerator, sand or aluminum oxide absorbent, and the sulfur
ization established in the Decision on Principles for the
content is determined by placing the boat in a tube furnace at
Development of International Standards, Guides and Recom-
1350°C in an air or oxygen-enriched atmosphere resulting in
mendations issued by the World Trade Organization Technical
complete combustion. Sulfur in the sample is completely
Barriers to Trade (TBT) Committee.
oxidized to sulfur dioxide. Moisture and particulates are
removed from the gas stream by traps filled with anhydrous
magnesium perchlorate. The gas stream is then passed through
a cell in which sulfur dioxide concentration is measured by an
infrared (IR) absorption detector at a precise wavelength in the
This test method is under the jurisdiction ofASTM Committee D24 on Carbon
Black and is the direct responsibility of Subcommittee D24.66 on Environment,
Health, and Safety. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2020. Published December 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2010. Last previous edition approved in 2016 as D7679 – 16. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7679-16R20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7679 − 16 (2020)
IR spectrum.The IR absorption detects sulfur dioxide through- 6.5 Sea Sand, purified by acid and calcinated (optional).
out the entire combustion process. The integral of the detector
6.6 Aluminum Oxide, optional.
signal is the basis for the total sulfur content of a sample.
6.7 Calibration Standards.
4.2 This test method is for use with commercially available
sulfur analyzers equipped to carry out the combustion and
7. Sampling
measurement operations automatically.
7.1 Collect feedstock oil as specified in Practices D4057 or
4.3 The sulfur analyzer shall be calibrated using appropriate
D4177.
calibration standards (see 6.7).
7.2 Sample—This is the portion or aliquot of the feedstock
4.4 The instrument may be configured to analyze more than
oil for use in obtaining a result.
one element such as a carbon-sulfur analyzer. In this case, the
7.3 Preparation—Warm viscous samples until they are fluid
analyzer has individual detectors for each element that are
and shake for 5 s.
arranged in series.
7.4 Transfer—Use any convenient, clean syringe or pipet to
5. Apparatus
transfer a sample to the combustion boat as described in
Section 10.
5.1 There are a number of commercially available instru-
ments designed to measure sulfur content in organic materials
8. Preparation of Apparatus
including sulfur and carbon-sulfur combustion analyzers. This
test method makes no specifications regarding system designs.
8.1 Assemble the apparatus according to the manufacturer’s
instructions.
5.2 Functionally,however,thefollowingarespecifiedforall
instruments:
8.2 Stabilize the furnace temperature at 1350 6 15°C.
5.2.1 An analytical balance, or equivalent, that is capable of
8.3 Makeaminimumoftwodeterminationstoconditionthe
a weighing sensitivity of 0.1 mg or better resolution.
equipment or follow the manufacturer’s recommendation to
5.2.2 The combustion tube and boat are made of a suitable
condition equipment before calibrating the instrument.
material such as mullite, porcelain, or zircon.
5.2.3 The sample is absorbed onto a solid which may
9. Calibration
include the following materials: (1) tungsten oxide based
9.1 Calibrate the instrument per the manufacturer’s recom-
accelerator; (2) Sea sand; (3) Aluminum oxide. Refer to the
mendation using appropriate sulfur calibration standards.
instrument manufacturer’s recommendations.
5.2.4 The sample is combusted at a temperature of 1350 6 9.2 Adjustment of Response of Measurement System—
Weigh approximately 0.1 to 0.2 g of calibration standard or use
15°C in an air or oxygen-enriched atmosphere.
5.2.5 The combustion gas is passed through an absorbent the recommended mass per manufacturer. Analyze the sample
(see Section 10). Repeat this procedure. Adjust the instrument
(anhydrous magnesium perchlorate) to remove water vapor.
5.2.6 Thedetectionsystemmeasuressulfurdioxideusingan as recommended by the manufacturer until the absence of drift
is indicated. Insure the minimum analysis time is sufficient for
IR absorption detector at a wavelength suitable for linear
responses with respect to the concentration over the full range complete combustion of the sample.
of possible concentrations.
9.3 Calibration Procedure—Follow the calibration proce-
dure recommended by the manufacturer. Confirm the calibra-
6. Reagents
tion by analyzing a reference material of known sulfur con-
6.1 Purity of Reagents—Reagent-grade chemicals shall be
centration. Reference standards should be similar to feedstock
used in all tests. Unless otherwise indicated, it is intended that
oils with sulfur content in the range of approximately 0 to 5 %.
all reagents shall conform to the specifications of the Commit-
The measured value should be within allowable limits of the
tee on Analytical Reagents of the American Chemical Society
known value. If not, repeat the procedure. If acceptable results
where such specifications are available. Other grades may be
are not obtained, refer to the manufacturer’s instructions for
used, provided it is first ascertained that the reagent is of
calibration.
sufficiently high purity to permit its use without lessening the
accuracy of the determination.
10. Procedure
6.2 Magnesium Perchlorate.
10.1 Stabilize and verify calibration of the analyzer (see
Sections 8 and 9).
6.3 Oxygen, high purity, 99.9 %.
10.2 Confirm the furnace temperature is 1350 6 15°C.
6.4 Tungsten (VI) Oxide Accelerator, containing potassium
dihydrogen-phosphate (optional).
10.3 Weigh an appropriate mass of accelerator or absorbent
into the combustion boat.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
listed by the American Chemical Society, see Annual Standards for Laboratory Sulfur calibration and reference standards are typically available from the
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia instrument manufacturer, National Institute of Standards and Technology’s (NIST),
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, http://www.nist.gov, and are also available from Alpha Resources, 3090 Johnson
MD. Road, Stevensville, MI 49127, www.alpharesources.com.
D7679 − 16 (2020)
NOTE 1—Use a material and mass recommended by the instrument
12.3 A type 1 inter-laboratory precision program was con-
manufacturer suitable for the combustion boat in use. Calibration stan-
ducted. Both repeatability and reproducibility represent short-
dards and feedstock samples should be analyzed using a similar mass of
term (daily) testing conditions. The testing was performed in
accelerator or absorbent.
each laboratory performing the test twice on each of two days
10.4 Weigh approximately 0.1 to 0.2 g of the sample into
(total of four tests). A test result is the value obtained from a
the combustion boat on top of the accelerator or absorbent.
single determination. Acceptable difference values were not
10.5 Record the sample weight. measured.
10.6 A portion of the accelerator or absorbent within the
12.4 Theresultsoftheprecisioncalculationsforthistestare
boat may be used to cover the sample, or alternatively,
giveninTable1fortheHighTemperatureCombustionMethod
additional accelerator or absorbent may be weighed and added
A.The materials are arranged in ascending “mean level” order.
to cover the sample.
12.5 Repeatability—The pooled relative repeatability, (r), of
NOTE 2—When covering the sample use care to insure none of the
this test has been established as 5.72 %. Any other value in
sample is accidentally removed from the combustion boat due to contact
Table 1 may be used as an estimate of repeatability, as
with a spatula or other tool used to transfer or position the accelerator or
appropriate. The difference between two single test results (or
absorbent.
determinations) found on identical test material under the
10.7 Initiate the analysis and place the boat in the instru-
repeatability conditions prescribed for this test will exceed the
ment using a boat puller or an auto-sampler mechanism.
repeatability on an average of not more than once in 20 cases
10.8 When the analysis is complete, the instrument should
in the normal and correct operation of the method. Two single
indicate the sulfur value. Refer to the manufacturer’s recom-
test results that differ by more than the appropriate value from
mended procedure.
Table 1 must be suspected of being from different populations
and some appropriate action taken.
11. Report
NOTE 3—Appropriate action may be an investigation of the test method
11.1 The percent sulfur value is obtained directly from the
procedure or apparatus for faulty operation or the declaration of a
apparatus.
significant difference in the two materials, samples, etc., which generated
the two test results.
11.2 Report results to the nearest 0.01 %.
12.6 Reproducibility—The pooled relative reproducibility,
12. Precision and Bias
(R) of this test has been established as 11.85 %. Any other
value in Table 1 may be used as an estimate of reproducibility,
12.1 These precision statements have been prepared in
as appropriate. The difference between two single and inde-
accordance with Practice D4483. Refer to this practice for
pendent test results found by operators working under the
terminology and other statistical details.
prescribed reproducibility conditions in different laboratories
12.2 The precision results in this precision and bias section
on identical test material will exceed the reproducibility on an
give an estimate of the precision of this test method with the
average of not more than once in 20 cases in the normal and
materials used in the particular interlaboratory program de-
correct operation of the method. Two single test results
scribed below.The precision parameters should not be used for
produced in different laboratories that differ by more than the
acceptance or rejection testing of any group of materials
appropriate value from Table 1 must be suspected of being
without documentation that they are applicable to those par-
from different populations and some appropriate investigative
ticular materials and the specific testing protocols of the test
action taken.
method. Any appropriate value may be used from Table 1 for
the High Temperature Combustion Method A. An alternate 12.7 Bias—Intestmethodterminology,biasisthedifference
combustionmethodforcarboncontent,CHNS,wasincludedin between an average test value and the reference (true) test
the interlaboratory program used to generate this precision property value. Reference values do not exist for this test
statement since a few labs use this instrumental method. method since the value or level of the test property is
Precision data specific to the CHNS method is found in Table exclusively defined by the test method. Bias, therefore, cannot
2. be determined.
TABLE 1 Precision Parameters for Test Method D7679, Type 1 Precision, High Temperature Combustion, Sulfur Content of Feedstock
Units
Percent
Number of
Material Mean Level Sr r (r) SR R (R)
Laboratories
9. Ethylene Cracker Residue 7 0.1378 0.0121 0.0343 24.92 0.0175 0.0494 35.88
10. NIST 1621e (0.95 % S) 7 0.9739 0.0195 0.0552 5.67 0.0435 0.1232 12.65
11. NIST 1622e (2.1 % S) 7 2.2038 0.0298 0.0843 3.83 0.1007 0.2851 12.93
...