Standard Test Method for Determination of Asphaltenes (Heptane Insolubles) in Crude Petroleum and Petroleum Products

SCOPE
1.1 This test method covers a procedure for the determination of the heptane insoluble asphaltene content of gas oil, diesel fuel, residual fuel oils, lubricating oil, bitumen, and crude petroleum that has been topped to an oil temperature of 260oC (seeA1.2.1.1).
1.2 The precision is applicable to values between 0.50 and 30.0 % m/m. Values outside this range may still be valid but may not give the same precision values.
1.3 Oils containing additives may give erroneous results.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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.

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ASTM D6560-00 - Standard Test Method for Determination of Asphaltenes (Heptane Insolubles) in Crude Petroleum and Petroleum Products
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An American National Standard
Designation:D6560–00
Designation: IP143/01
Standard Test Method for
Determination of Asphaltenes (Heptane Insolubles) in Crude
,
1 2
Petroleum and Petroleum Products
This standard is issued under the fixed designation D6560; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Petroleum Products
2.2 IP Standard:
1.1 This test method covers a procedure for the determina-
Specifications for IP Standard Thermometers
tion of the heptane insoluble asphaltene content of gas oil,
diesel fuel, residual fuel oils, lubricating oil, bitumen, and
3. Terminology
crude petroleum that has been topped to an oil temperature of
3.1 Definitions:
260°C (see A1.2.1.1).
3.1.1 asphaltenes, n—wax-free organic material insoluble
1.2 The precision is applicable to values between 0.50 and
in heptane, but soluble in hot toluene (benzene).
30.0% m/m. Values outside this range may still be valid but
may not give the same precision values.
NOTE 1—Benzeneisincludedinthisdefinitionsolelyonthebasisofits
1.3 Oils containing additives may give erroneous results. classical references in the definition of asphaltenes. The precision of this
test method when using toluene has been found to be the same as when
1.4 The values stated in SI units are to be regarded as the
using benzene.
standard.
1.5 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 A test portion of the sample is mixed with heptane and
responsibility of the user of this standard to establish appro-
the mixture heated under reflux, and the precipitated asphalt-
priate safety and health practices and determine the applica-
enes, waxy substances, and inorganic material are collected on
bility of regulatory limitations prior to use.
a filter paper. The waxy substances are removed by washing
with hot heptane in an extractor.
2. Referenced Documents
4.2 After removal of the waxy substances, the asphaltenes
2.1 ASTM Standards:
3 are separated from the inorganic material by dissolution in hot
D86 Test Method for Distillation of Petroleum Products
toluene, the extraction solvent is evaporated, and the asphalt-
D1298 TestMethodforDensity,RelativeDensity(Specific
enes weighed.
Gravity), or API Gravity of Crude Petroleum and Liquid
Petroleum Products by Hydrometer Method
5. Significance and Use
D4052 Test Method for Density and Relative Density of
5.1 Asphaltenes are the organic molecules of highest mo-
Liquids by Digital Density Meter
lecular mass and carbon-hydrogen ratio normally occurring in
D4057 Practice for Manual Sampling of Petroleum and
crude petroleum and petroleum products containing residual
Petroleum Products
material.Theymaygiveproblemsduringstorageandhandling
D4177 Practice for Automatic Sampling of Petroleum and
if the suspension of asphaltene molecules is disturbed through
excess stress or incompatibility. They are also the last mol-
1 ecules in a product to combust completely, and thus may be
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee one indicator of black smoke propensity. Their composition
D02.14 on Stability and Cleanliness of Liquid Fuels.
normally includes a disproportionately high quantity of the
Current edition approved June 10, 2000. Published July 2000.
sulfur, nitrogen, and metals present in the crude petroleum or
This standard is based on material published in the IP Standard methods for
petroleum product.
Analysis and Testing of Petroleum and Related Products and British Standard 2000
Parts, copyright The Institute of Petroleum, 61 New Cavendish Street, London,
W1M 8AR. Adapted with permission of The Institute of Petroleum.
3 5
Annual Book of ASTM Standards, Vol 05.01. Available from Institute of Petroleum, 61 New Cavendish St., London, WIM
Annual Book of ASTM Standards, Vol 05.02. 8AR, UK.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6560–00
TABLE 1 Test Portion Size, Flask, and Heptane Volumes
6. Apparatus
Estimated Asphaltene Test Portion Heptane Volume
6.1 General—Ground-glass joints from different sources
Content Size Flask Volume
may have one of two diameter to length ratios. For the
%m/m g mL mL
purposes of this test method, either is suitable, and for some
Less than 0.5 10 6 2 1000 300 6 60
applications, the diameter itself can be one of two . However,
0.5to2.0 8 6 2 500 240 6 60
Over 2.0 to 5.0 4 6 1 250 120 6 30
it is critical that the male and female parts of each joint are
Over 5.0 to 10.0 2 6 1 150 60 6 15
from the same series to avoid recession or protuberance.
Over 10.0 to 25.0 0.8 6 0.2 100 25 to 30
6.2 Condenser, with a coil or double surface, fitted with a
Over 25.0 0.5 6 0.2 100 25 6 1
34/45or34/35ground-glassjointatthebottomtofitthetopof
the extractor. Minimum length is 300 mm.
6.3 Reflux Extractor,conformingtothedimensionsgivenin 6.8 Filter Papers, Whatman Grade 42, 110 or 125-mm
Fig.1.Tolerancesare 61mmontheheightandouterdiameter diameter.
(OD) of the extractor body and 6 0.5 mm on all other 6.9 Analytical Balance, capable of weighing with an accu-
dimensions. The female ground-glass joint at the top shall racy of 0.1 mg.
match the male at the bottom of the condenser, and the male 6.10 Forceps, of stainless steel, spade ended.
ground-glass joint at the bottom shall match the female of the
6.11 Timing Device, electronic or manual, accurate to 1.0 s.
conical flask. 6.12 Oven, capable of maintaining a temperature from 100
6.4 Conical Flasks, of borosilicate glass of appropriate
to 110°C.
capacity (see 11.2 and Table 1), with ground-glass joints to fit 6.13 Graduated Cylinders, of 50 and 100 mL capacity.
the bottom of the extractor.
6.14 Stirring Rods, of glass or polytetrafluoroethylene
(PTFE), 150 by 3-mm diameter.
NOTE 2—Sizes 24/39, 24/29, 29/43 or 29/32 are suitable.
6.15 Cooling Vessel, consisting of either a dessicator with-
6.5 Stopper, of borosilicate glass of a size to fit the conical
out desiccant, or another suitable tightly-stoppered vessel.
flask.
6.16 Mixer, high-speed, nonaerating.
6.6 Evaporating Vessel, of borosilicate glass. Either a hemi-
spherical dish of approximately 90 mm diameter, or another 7. Reagents
suitable vessel used in conjunction with a rotovapor.
7.1 Toluene (methylbenzene) [C H CH ],analyticalreagent
6 5 3
or nitration grade.
NOTE 3—A rotovapor in conjunction with a nitrogen atmosphere
7.2 Heptane [C H ], analytical reagent grade.
reduces the hazard of toluene evaporation (see 11.7).
7 16
6.7 Filter Funnel, of borosilicate glass, approximately 100
8. Sampling
mm diameter.
8.1 Unless otherwise specified, take samples by the proce-
dures described in Practice D4057 or D4177.
9. Test Portion Preparation
9.1 Test portions from the laboratory samples shall be
drawn after thorough mixing and subdivision. Heat viscous
samples of residual fuels to a temperature that renders the
sample liquid, but not above 80°C, and homogenize, using the
mixer (see 6.16) as necessary.
9.2 Heat samples of penetration grade bitumens to a tem-
perature not exceeding 120°C, and stir well before taking an
aliquot.
9.3 Samples of hard bitumens shall be ground to a powder
before an aliquot is taken.
9.4 Samples of crude petroleum shall be prepared in accor-
dance with the procedure described in theAnnexA1, unless it
is known that the crude petroleum contains negligible quanti-
ties of material boiling below 80°C.
10. Apparatus Preparation
10.1 Clean all glass flasks (see 6.4) and dishes (see 6.6)by
a means that matches the cleanliness obtained by the use of a
strongly oxidizing agent, such as chromosulfuric acid, ammo-
nium peroxydisulfate in concentrated sulfuric acid at approxi-
mately 8 g/L, or sulfuric acid itself, soaking for at least 12 h,
FIG. 1 Extractor Available from Whatman Int. Ltd., Maidstone, UK.
D6560–00
followed by rinses in tap water, distilled water, and then paper, and then transfer the the residue in the flask as
acetone, using forceps only for handling. (Warning— completely as possible with successive quantities of hot
Chromosulfuricacidisahealthhazard.Itistoxic,arecognized heptane,usingtheusingthestirringrod(see6.14)asnecessary.
carcinogenasitcontainsCr(VI)compounds,whicharehighly Give the flask a final rinse with hot heptane, and pour the
corrosive and potentially hazardous in contact with organic rinsingsthroughthefilter.Settheflaskaside,withoutwashing,
materials. When using chromosulfuric acid cleaning solution, for use as specified in 11.6.
eye protection and protective clothing are essential. Never 11.5 Remove the filter paper and contents from the funnel,
pipette the cleaning solution by mouth.After use, do not pour and place in the reflux extractor (see 6.3). Using a flask
cleaning solution down the drain, but neutralize it with great different from that used initially, reflux with heptane (see 7.2)
care, owing to the concentrated sulfuric acid present, and atarateof2drops/sto4drops/sfromtheendofthecondenser
dispose of it in accordance with standard procedures for toxic for an extraction period of not less than 60 min, or until a few
laboratory waste (chromium is highly dangerous to the envi- drops of heptane from the bottom of the extractor leave no
ronment). Nonchromium containing, strongly oxidizing acid residue on evaporation on a glass slide.
cleaning solutions are also highly corrosive and potentially 11.6 Replacetheflaskbytheoneusedinitially,andtowhich
hazardousincontactwithorganicmaterials,butdonotcontain has been added 30 to 60 mLof toluene (see 7.1), and continue
chromium, which has its own special disposal problems. refluxinguntilalltheasphalteneshavebeendissolvedfromthe
10.2 For routine analysis, use a proprietary laboratory paper.
detergent to clean the glassware, followed by the rinses 11.7 Transferthecontentsoftheflasktoacleananddry(see
described in 10.1. When the detergent cleaning no longer Section10)evaporatingvessel(see6.6),weighedtothenearest
matches the cleanliness required based on visual appearance, 0.2 mg by tare against a similar dish. Wash out the flask with
use a strong oxidizing agent. successive small quantities of toluene to a total not exceeding
10.3 After rinsing, place the glassware in the oven (see 30 mL. Remove the toluene by evaporation on a boiling water
6.12) for 30 min, and cool in the cooling vessel (see 6.15) for bath (Warning—Perform the evaporation in a fume hood.), or
30 min before weighing. byevaporationinarotovaporunderanatmosphereofnitrogen.
11.8 Dry the dish and contents in the oven (see 6.12)at100
11. Procedure
to 110°C for 30 min. Cool in the cooling vessel (see 6.15) for
30 to 60 min and reweigh by tare against the dish used
11.1 Estimate the asphaltene content of the sample, or
previously for this purpose, and which has been subjected to
residue obtained from the procedure in the Annex A1, and
the same heating and cooling procedure as was the dish
weigh the quantity, to the nearest 1 mg for masses above 1 g
containing asphaltenes.
and to the nearest 0.1 mg for masses of 1 g and below (see
Table 1), into a flask (see 6.4) of appropriate capacity (see
NOTE 4—Asphaltenes are very susceptible to oxidation, and it is
Table 1).
important that the procedure specified in the final drying stage is adhered
11.2 Add heptane (see 7.2) to the test portion in the flask at
to exactly as regards to temperature and time 6 1 min.
a ratio of 30 mL to each1gof sample if the expected
12. Calculation
asphaltene content is below 25% m/m. For samples with an
expected asphaltene content of above 25% m/m, a minimum 12.1 Calculate the asphaltene content, A, in % m/m, of
petroleum products as follows:
heptane volume of 25 mL shall be used (see Table 1).
11.3 Boil the mixture under reflux for 60 6 5 min. Remove
A 5100 ~M/G! (1)
theflaskandcontentsattheendofthisperiod,cool,closewith
where:
a stopper (see 6.5), and store in a dark cupboard for 90 to 150
M = is the mass of asphaltenes, in grams, and
min, calculated from the time of removal from reflux.
G = is the mass of test portion, in grams.
11.4 Place the filter paper, folded as shown in Fig. 2 (so as
12.2 Calculate the asphaltene content, C, in % m/m, of
to prevent loss of asphaltenes by creeping), in the filter funnel,
crude petroleum prepared in the manner described in the
using forceps. Thereafter, handle the filter paper only with
Annex, as follows:
forceps. Without agitation, decant the liquid into the filter
C 5100 ~MR/GD! (2)
where:
M = is the mass of asphaltenes, in grams,
R = is the mass of the residue from distillation, in grams,
G = is the mass of the residue aliquot, in grams, and
D = is the mass of crude petroleum sample distilled, in
grams.
13. Report
13.1 Report the following information:
13.1.1 The heptane insoluble asphaltene content of values
less than 1.00% m/m, to the nearest 0.05% m/m, by Test
FIG. 2 Filter Paper Method D6560.
D6560–00
13.1.2 The heptane insoluble asphaltene content of values where A is the average result, in % m/m.
of 1.0% m/m and greater, to the nearest 0.1% m/m, by Test
14.3 Reproducibility—The difference between two single
Method D6560.
and independent results obtained by different operators work-
ingindifferentlaboratoriesonnominallyidenticaltestmaterial
14. Precision and Bias
would, in the normal and correct operation of the test method,
14.1 Precision—The precision values were determined in
exceed the value below in only one case in twenty.
an interlaboratory program, using benzene as solvent, in 1956.
R 50.2 A (4)
A second interlaboratory program, using toluene as solvent,
where A is the average result, in % m/m.
was carried out in 1975 to confirm the precision. No data from
the 1956 evaluation program can be found.
14.4 Bias—Since heptane insoluble asphaltenes are defined
by this test method, no bias can be assigned. The term
NOTE 5—A recent (1998) interlaboratory program in France on four
asphaltenes may be associated with other similar procedures
samples with asphaltene contents in the range from 0.50 to 22.0% m/m
using alkanes as precipitating agents other than heptane. In
resulted in estimated precision values very similar to those given in 14.2
general, lighter alkanes will give higher results and heavier
and 14.3, except for the reproducibility at very low levels (<2.0% m/m),
which was significantly worse.
alkanes will give lower res
...

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