ASTM D5187-91(2007)
(Test Method)Standard Test Method for Determination of Crystallite Size (Lc of Calcined Petroleum Coke by X-Ray Diffraction
Standard Test Method for Determination of Crystallite Size (L<inf>c</inf> of Calcined Petroleum Coke by X-Ray Diffraction
SIGNIFICANCE AND USE
The crystallinity of petroleum coke, as reflected by the Lc value, is a general measure of quality affecting suitability for end use and is a function of the heat treatment.
The crystallite thickness is used to determine the extent of such heat treatment, for example, during calcination. The value of the Lc determined is not affected by coke microporosity or the presence of foreign, non-crystalline materials such as dedust oil.
SCOPE
1.1 This test method covers the determination of the mean crystallite thickness of a representative, pulverized sample of calcined petroleum coke by interpretation of a X-ray diffraction pattern produced through conventional X-ray scanning techniques.
1.2 Calcined petroleum coke contains crystallites of different thicknesses. This test method covers the determination of the average thickness of all crystallites in the sample by empirical interpretation of the X-ray diffraction pattern. The crystallite diameter ( La) is not determined by this test method.
1.3 The values stated in SI (metric) units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information purposes only.
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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5187–91(Reapproved 2007)
Standard Test Method for
Determination of Crystallite Size (L of Calcined Petroleum
c
Coke by X-Ray Diffraction
This standard is issued under the fixed designation D5187; 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 3.1.2 L —the mean or average thickness of crystallites in a
c
sample.Itisexpressedasalineardimensioninangstromunits,
1.1 This test method covers the determination of the mean
−1
˚
A (10 nm).
crystallite thickness of a representative, pulverized sample of
3.1.3 hkl(002)—the Miller indices of the crystalline planes
calcinedpetroleumcokebyinterpretationofaX-raydiffraction
of graphite corresponding to a lattice spacing (d) of 3.35 Å.
pattern produced through conventional X-ray scanning tech-
3.1.4 Q—theglancingangleproducedwhenaparallelbeam
niques.
of uniform X-rays impinges upon a crystalline lattice. This
1.2 Calcined petroleum coke contains crystallites of differ-
angle is measured by the X-ray goniometer and is usually
ent thicknesses. This test method covers the determination of
expressed in ° 2Q.
the average thickness of all crystallites in the sample by
empirical interpretation of the X-ray diffraction pattern. The
4. Summary of Test Method
crystallite diameter (L ) is not determined by this test method.
a
4.1 A packed sample pulverized to less than 75 µm is
1.3 The values stated in SI (metric) units are to be regarded
subjected to a monochromatic X-ray beam and rotated to
as the standard. The inch-pound units given in parentheses are
produce a diffraction pattern under specific conditions. The
provided for information purposes only.
˚
locationandshapeofthepeakwith hkl =(002)at d =3.35;A
1.4 This standard does not purport to address all of the
is used to calculate the L by manual interpretation of the peak
c
safety concerns, if any, associated with its use. It is the
or by computer simulation.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 The crystallinity of petroleum coke, as reflected by the
2. Referenced Documents L value,isageneralmeasureofqualityaffectingsuitabilityfor
c
2 end use and is a function of the heat treatment.
2.1 ASTM Standards:
5.2 The crystallite thickness is used to determine the extent
D346 Practice for Collection and Preparation of Coke
of such heat treatment, for example, during calcination. The
Samples for Laboratory Analysis
value of the L determined is not affected by coke microporos-
c
D2013 Practice for Preparing Coal Samples for Analysis
ityorthepresenceofforeign,non-crystallinematerialssuchas
D2234/D2234M Practice for Collection of a Gross Sample
dedust oil.
of Coal
D4057 Practice for Manual Sampling of Petroleum and
6. Apparatus
Petroleum Products
6.1 X-Ray Powder Diffractometer, equipped with an X-ray
3. Terminology source, a monochromator or filter for restricting the wave-
length range, a sample holder, a radiation detector, a signal
3.1 Definitions of Terms Specific to This Standard:
processor, and readout (chart or computer memory). The
3.1.1 crystallites—stacks of graphitic carbon platelets lo-
diffractometer must be capable of rate scanning at 1° per
cated parallel to one another.
minute or incrementally step scanning at 0.2° per step.
6.2 Sample Holders, as specified by the manufacturer of the
This test method is under the jurisdiction of ASTM Committee D02 on
diffractometer that enables packing of a pulverized sample of
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
sufficient thickness to expose a level, smooth surface to the
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved May 1, 2007. Published June 2007. Originally X-ray beam.
published in 1991. Last previous edition approved in 2002 as D5187–91 (2002).
6.3 Briquetting Press, capable of generating pressures up to
DOI: 10.1520/D5187-91R07.
10000 psi (69 MPa).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.4 Compressible Aluminum Caps, used as a support for
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on producing a briquetted sample.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5187–91 (2007)
6.5 Silicon or Quartz Sample, available from National Standards to prepare standard powder diffraction patterns.
Institute of Standards and Technology (NIST). Clamp a glass slide over the top face to form a temporary
cavity wall. With the holder in a vertical position, drift the
7. Reagents and Materials
powdered sample into the end opening. If necessary, use a
7.1 Purity of Reagents—Reagent grade chemicals shall be cardboard pusher cut to fit the cavity to lightly compress the
usedinalltests.Itisintendedthatallreagentsshallconformto
sample so it will remain in the cavity. Return the holder to a
the specifications of the Committee onAnalytical Reagents of horizontal position and carefully remove the glass slide. Place
the American Chemical Society where such specifications are
the sample in diffractometer holder.
available. Other grades may be used, provided it is first 8.5.4 Briquetting Technique—Weighout4.0gofthesample
ascertained that the reagent is of sufficiently high purity to
onto a watch glass and pipette exactly 3 mL of the binding
permit its use without lessening the accuracy of the determi- agentontothesampleandmixthoroughlywithaspatula.Place
nation.
the sample under an infrared heat lamp and allow the acetone
7.2 Acetone. to evaporate. Typically, about 1 or 2 min will be required to
7.3 Polyethylene Glycol, (approximate molecular weight of
eliminate the acetone odor from sample. Break up the caked
200). sample with a spatula and transfer to an aluminum cap whose
7.4 Binding Agent—Prepare a 15 mass % solution of diameter is compatible with the sample holder of the diffrac-
polyethylene glycol and acetone by adding 15 g of polyethyl- tometer. Place the cap in a briquetting press and press at
ene glycol to 85 g of acetone. 7000 psi (48 MPa). Transfer the pelletized sample to the
sample holder and insert into the diffractometer for analysis.
8. Sample Preparation
9. Calibration
8.1 For recommended practices for obtaining, handling and
preparing coke samples, refer to Test Methods D2013 and
9.1 Calibration consists of ensuring that the diffractometer
D2234/D2234M and Practices D346 and D4057. The equip-
is in correct mechanical and optical alignment and intensities
ment and procedures for crushing and dividing are also
have been maximized through the procedures described in the
described in these test methods.
instrument manufacturer’s documentation. This is best accom-
8.2 Reduce and divide the gross sample to obtain a labora-
plished by a service engineer or in-house technician who has
tory analysis sample.
been well instructed in the correct alignment procedures
8.3 Divide, by riffling, a minimum of 100 g from the
suggested by the manufacture
...
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