ASTM D7060-12(2014)
(Test Method)Standard Test Method for Determination of the Maximum Flocculation Ratio and Peptizing Power in Residual and Heavy Fuel Oils (Optical Detection Method)
Standard Test Method for Determination of the Maximum Flocculation Ratio and Peptizing Power in Residual and Heavy Fuel Oils (Optical Detection Method)
SIGNIFICANCE AND USE
5.1 Asphaltenes are naturally occurring materials in crude petroleum and petroleum products containing residual material. The asphaltenes are usually present in colloidal suspensions, but they may agglomerate and flocculate if the suspension of asphaltene molecules is disturbed through excess stress or incompatibility. This test method provides compatibility parameters, which can be used to assess stability reserve and compatibility.
5.2 A blend is considered stable when the blend’s peptizing power is higher than the blend’s maximum flocculation ratio;3,4 both of them can be calculated using empirical blend rules. Refineries and terminal owners can prevent the flocculation of asphaltenes due to incompatibility by assessing the compatibility of fuels beforehand.
Note 4: See Appendix X1 for an example of prediction of compatibility.
SCOPE
1.1 This test method covers a procedure for quantifying the maximum flocculation ratio of the asphaltenes in the oil and the peptizing power of the oil medium, by an automatic instrument using an optical device.
1.2 This test method is applicable to atmospheric or vacuum distillation residues, thermally cracked residue, intermediate and finished residual fuel oils, containing at least 1 mass % asphaltenes. This test method has not been developed for asphalts.
Note 1: An optical probe detects the formation of flocculated asphaltenes. The start of flocculation is interpreted when a significant and sustained increase in rate-of-change of signal, as measured by the optical probe, ensures flocculation is in progress. The start of flocculation can be detected unambiguously when the sample contains at least 1 % mass asphaltenes as measured by Test Method D6560.
Note 2: This test method is applicable to products typical of Specification D396—Grades 5L, 5H, and 6, and Specification D2880—Grades 3-GT and 4-GT.
1.3 This test method was evaluated in an interlaboratory study in the nominal range of 32 to 76 for the maximum flocculation ratio and in the nominal range of 36 to 95 for peptizing power.
Note 3: The nominal range is determined by (min. sample mean—Reproducibility) to (max. sample mean + Reproducibility).
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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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Designation: D7060 − 12 (Reapproved 2014)
Standard Test Method for
Determination of the Maximum Flocculation Ratio and
Peptizing Power in Residual and Heavy Fuel Oils (Optical
Detection Method)
This standard is issued under the fixed designation D7060; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers a procedure for quantifying the
D396Specification for Fuel Oils
maximumflocculationratiooftheasphaltenesintheoilandthe
D2880Specification for Gas Turbine Fuel Oils
peptizingpoweroftheoilmedium,byanautomaticinstrument
D4057Practice for Manual Sampling of Petroleum and
using an optical device.
Petroleum Products
1.2 Thistestmethodisapplicabletoatmosphericorvacuum
D4177Practice for Automatic Sampling of Petroleum and
distillation residues, thermally cracked residue, intermediate
Petroleum Products
and finished residual fuel oils, containing at least 1 mass%
D4870Test Method for Determination of Total Sediment in
asphaltenes. This test method has not been developed for
Residual Fuels
asphalts.
D6300Practice for Determination of Precision and Bias
NOTE 1—An optical probe detects the formation of flocculated as-
Data for Use in Test Methods for Petroleum Products and
phaltenes. The start of flocculation is interpreted when a significant and
Lubricants
sustained increase in rate-of-change of signal, as measured by the optical
D6560Test Method for Determination ofAsphaltenes (Hep-
probe, ensures flocculation is in progress. The start of flocculation can be
detected unambiguously when the sample contains at least 1% mass
tane Insolubles) in Crude Petroleum and Petroleum Prod-
asphaltenes as measured by Test Method D6560.
ucts
NOTE 2—This test method is applicable to products typical of Specifi-
D6792Practice for Quality System in Petroleum Products
cation D396—Grades 5L, 5H, and 6, and Specification D2880—Grades
and Lubricants Testing Laboratories
3-GT and 4-GT.
1.3 This test method was evaluated in an interlaboratory
3. Terminology
study in the nominal range of 32 to 76 for the maximum
3.1 Definitions:
flocculation ratio and in the nominal range of 36 to 95 for
3.1.1 asphaltenes, n—(rarely used in the singular), in petro-
peptizing power.
leum technology, represent an oil fraction that is soluble in a
NOTE 3—The nominal range is determined by (min. sample mean—
specified aromatic solvent but separates upon addition of an
Reproducibility) to (max. sample mean + Reproducibility).
excess of a specified paraffinic solvent.
3.1.1.1 Discussion—In this test method, the aromatic sol-
1.4 The values stated in SI units are to be regarded as
vent is 1-methylnapthalene, and the paraffinic solvent is
standard. No other units of measurement are included in this
n-hexadecane.
standard.
3.1.2 compatibility, n— of crude oils or of heavy fuel oils,
1.5 This standard does not purport to address all of the
the ability of two or more crude oils or fuel oils to blend
safety concerns, if any, associated with its use. It is the
together within certain concentration ranges without evidence
responsibility of the user of this standard to establish appro-
of separation, such as the formation of multiple phases.
priate safety and health practices and determine the applica-
3.1.2.1 Discussion—Incompatible heavy fuel oils or crude
bility of regulatory limitations prior to use.
oils, when mixed or blended, result in the flocculation or
precipitation of asphaltenes. Some oils may be compatible
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 D02.14 on Stability and Cleanliness of Liquid Fuels. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2014. Published February 2015. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2004. Last previous edition approved in 2012 as D7060–12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7060-12R14. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7060 − 12 (2014)
within certain concentration ranges in specific mixtures, but mixture of 1-methylnaphthalene and cetane, to keep as-
incompatible outside those ranges. phaltenes in a colloidal solution.
3.2.9 reciprocal dilution, n—dilution ratio of sample in
3.1.3 flocculation, n— of asphaltenes from crude oils or
heavy fuel oils, the aggregation of colloidally dispersed as- solvent mixture of 1-methylnaphthalene and cetane.
phaltenes into visibly larger masses which may or may not
3.3 Symbols:
settle.
FR = maximum flocculation ratio
max
3.1.4 peptization, n— of asphaltenes in crude oils or heavy
FR = flocculation ratio at critical dilution
x
fuel oils, the dispersion of asphaltenes to produce a colloidal
Po = peptizing power
dispersion.
Xmin = critical cetane dilution
3.1.5 stability reserve, n— in petroleum technology, the
Xc = critical dilution
property of an oil to maintain asphaltenes in a peptized state
and prevent flocculation of the asphaltenes.
4. Summary of Test Method
3.1.5.1 Discussion—An oil with a low stability reserve is
4.1 Six portions of the sample are diluted in various ratios
likelytoundergoflocculationofasphalteneswhenstressed(for
with 1-methylnaphthalene. Each solution is inserted into the
example, extended heated storage) or blended with a range of
automatic apparatus, and titrated with cetane until flocculation
otheroils.Twooilseachwithahighstabilityreservearelikely
of asphaltenes is detected by the optical probe. The first two
to maintain asphaltenes in a peptized state and not lead to
solutions are titrated with cetane in coarse determinations in
flocculation when blended together.
which the flocculation ratio is decreased in 5% steps. The
3.2 Definitions of Terms Specific to This Standard:
coarse determinations help to establish suitable starting values
for the fine determinations, in which the flocculation ratio is
3.2.1 critical cetane dilution, n—number of millilitres of
cetane with which1gof undiluted sample can be diluted until decreased in 1% steps. The four flocculation ratios at critical
dilution, measured during the fine determinations, are used to
it just does not flocculate the asphaltenes.
calculate the maximum flocculation ratio of the sample’s
3.2.2 critical dilution, n—number of millilitres of
asphaltenes and the peptizing power of the sample’s oil
1-methylnaphthalene and cetane with which1gof undiluted
medium.
sample can be diluted until it just does not flocculate the
asphaltenes.
5. Significance and Use
3.2.2.1 Discussion—The number of millilitres of
5.1 Asphaltenes are naturally occurring materials in crude
1-methylnaphthaleneandcetaneisvariableanddependsonthe
petroleum and petroleum products containing residual mate-
ratioofsampleto1-methylnaphthaleneatthestartingpointand
rial. The asphaltenes are usually present in colloidal
the sample type.
suspensions, but they may agglomerate and flocculate if the
3.2.3 flocculation ratio, n—percentage by volume of
suspensionofasphaltenemoleculesisdisturbedthroughexcess
1-methylnaphtalene in a mixture of 1-methylnaphthalene and
stress or incompatibility. This test method provides compat-
cetane.
ibilityparameters,whichcanbeusedtoassessstabilityreserve
3.2.4 flocculationratioatcriticaldilution,n—percentageby
and compatibility.
volume of 1-methylnaphthalene in a mixture of
5.2 Ablend is considered stable when the blend’s peptizing
1-methylnaphthalene and cetane at the inflection point.
3,4
powerishigherthantheblend’smaximumflocculationratio;
3.2.5 inflection point, n—last step during the titration with
both of them can be calculated using empirical blend rules.
cetane,whereflocculationofasphaltenesis notdetectedbythe
Refineries and terminal owners can prevent the flocculation of
optical probe as a significant and sustained increase in rate-of-
asphaltenesduetoincompatibilitybyassessingthecompatibil-
change of signal.
ity of fuels beforehand.
NOTE 4—See Appendix X1 for an example of prediction of compat-
3.2.6 maximum flocculation ratio, n—of asphaltenes, mini-
ibility.
mum required solvency power, expressed as percentage by
volume of 1-methylnaphthalene in a mixture of
6. Interferences
1-methylnaphthalene and cetane, to keep the asphaltenes in a
6.1 High content of insoluble inorganic matter (sediment)
colloidal solution.
has some interference in this test method. In this case, the
3.2.6.1 Discussion—Maximumflocculationratioisthefloc-
insoluble matter shall be removed by filtration according to
culation ratio at extrapolated infinite dilution of the sample.
Test Method D4870.
3.2.7 oil medium, n—that portion of a sample of heavy fuel
6.2 The presence of wax, present in paraffinic crudes or
oil or crude oil that surrounds and colloidally disperses the
fuels from such crudes, does not interfere.
asphaltenes.
3.2.7.1 Discussion—For purposes of this test method, an oil
sample is considered to be composed of an oil medium
(sometimes called an oil matrix or maltenes) and asphaltenes. Berryman, T. J., and Lewis, C. P. G., “The Stability of Residual Fuels. Theory
and Practice of the Shell Concept,” 16th CIMAC Conference, Oslo, 1985.
3.2.8 peptizing power, n—available solvency power, ex-
Berg van den, F. G. A., “Developments in Fuel Oil Blending,” IASH 7th
pressed as percentage by volume of 1-methylnaphthalene in a International Conference, Graz,Austria, 2000.
D7060 − 12 (2014)
7. Apparatus 8. Reagents and Materials
7.1 Integrated Automated Analytical Measurement 8.1 Purity of Reagents—Reagent grade chemicals shall be
System—This test method uses an integrated automated ana- used in all tests. Unless otherwise indicated, it is intended that
lytical measurement system comprised of a PC–based com- all reagents conform to the specifications of the Committee on
puter and two titration stations (Fig. 1). See Annex A1 for Analytical Reagents of theAmerican Chemical Society where
detailed information. such specifications are available. Other grades may be used,
provided it is first ascertained that the reagent is of sufficiently
7.2 The computer controls test sequencing, acquires and
high purity to permit its use without lessening the accuracy of
accumulates optical probe signal data, provides processing
the determination.
calculations, and automatically produces a report of important
test parameters. The computer is capable of controlling one or 8.2 Asphaltene Solution (3 g/L) —Dissolve 0.15 g of dry
two independent titration stations. asphaltenes in 1-methylnaphthalene and dilute to 50 mL. A
procedure to obtain asphaltenes is described in Appendix X2.
7.3 Each titration station consists of the following:
Prepare fresh daily, as needed.
7.3.1 Automatic titration unit,
7.3.2 Heater, 8.3 Cetane (n-Hexadecane). (Warning—Irritating to respi-
7.3.3 Magnetic stirrer, ratory system and skin.)
7.3.4 Optical probe, and
8.4 Cleaning Solvent, technical grade, 95% purity, for
7.3.5 Reaction cell plus lid.
cleaning. It consists of one of the following:
7.4 Magnetic Stirrer/Hotplate, thermostatically controlled. 8.4.1 Tetrahydrofuran, stabilized. (Warning—Extremely
flammable. Irritating to eyes and respiratory system.)
7.5 Stirring Bar, magnetic, PFTE-coated, 25 mm in length.
Reagent Chemicals, American Chemical Society Specifications, American
The sole source of supply of the apparatus known to the committee at this time
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
isAutomatedStabilityAnalyser,(UserManual,Version2),availablefromZematra,
listed by the American Chemical Society, see Annual Standards for Laboratory
3194 DG Hoogvliet, The Netherlands. If you are aware of alternative suppliers,
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
please provide this information to ASTM International Headquarters. Your com-
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
ments will receive careful consideration at a meeting of the responsible technical
MD.
committee, which you may attend.
FIG. 1 Titration Stations of Integrated Automated Analytical Measurement System
D7060 − 12 (2014)
8.4.2 Toluene. (Warning—Flammable. Health Hazard.) 9.2.3.2 Add, according to Table 1, while continuously
8.4.3 Xylene. (Warning—Flammable. Harmful by inhala- stirring, an appropriate volume of 1-methylnaphthalene to the
tion and in contact with skin. Irritating to skin.) nearest 0.01 mL.
9.2.3.3 Put the lid in place. Initiate the test procedure (12.3)
8.5 n-Heptane.(Warning—Flammable.Vaporharmful.Va-
within 10 min.
por may cause flash fire.)
NOTE 6—Never use excessive force when placing the lid in place.
8.6 1-Methylnaphthalene. (Warning—Harmful if swal-
lowed. Irritating to skin.)
10. Preparation of Apparatus
8.7 Quality Control (QC) Sample, a stable and homoge-
10.1 Prepare the instrument for operation in accordance
neous residual fuel oil. The QC sample contains at least 1
with the manufacturer’s instructions.
mass% asphaltenes and has approximate viscosities in the
10.2 Inspecttheopticalprobe’sglasssurfaceforcleanliness
range of 180 to 380 mm /s at 50°C.
and damage before use. Connect the optical probes to the
respective apparatus’titration station. Place the optical probes
9. Sampling and Test Specimens
in the holder at the back of the corresponding titration station.
9.1 Sampling:
10.3 CleaningInstructions—Performthefollowingcleaning
9.1.1 ObtainsamplesinaccordancewithPracticesD4057or
procedure after the test procedure (see 12.3).
D4177.
10.3.1 Removethedosingtube.Cleanthetubewithaclean,
9.1.2 Samples of very viscous materials may be warmed
lintless cloth. Place the tube into its storage place.
until they are reasonably fluid before they are sampled.
10.3.2 Carefullyremovetheopticalsensorfromthereaction
9.1.3 Store samples prior to taking test specimens at ambi-
cell. (Warning—The hot sensor and reaction cell can cause
ent temperatures.
severe burns.) Clean the optical sensor with a clean, lintless
9.2 Test Specimen Preparation:
soft cloth using an appropriate solvent (see 8.4). Place the
9.2.1 Sample Fuel Temperature—Warm viscous samples
sensor in the holder on top of the reaction cell heater.
until they can be mixed readily before opening the storage
10.3.3 Take the reactio
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7060 − 12 D7060 − 12 (Reapproved 2014)
Standard Test Method for
Determination of the Maximum Flocculation Ratio and
Peptizing Power in Residual and Heavy Fuel Oils (Optical
Detection Method)
This standard is issued under the fixed designation D7060; 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*Scope
1.1 This test method covers a procedure for quantifying the maximum flocculation ratio of the asphaltenes in the oil and the
peptizing power of the oil medium, by an automatic instrument using an optical device.
1.2 This test method is applicable to atmospheric or vacuum distillation residues, thermally cracked residue, intermediate and
finished residual fuel oils, containing at least 1 mass % asphaltenes. This test method has not been developed for asphalts.
NOTE 1—An optical probe detects the formation of flocculated asphaltenes. The start of flocculation is interpreted when a significant and sustained
increase in rate-of-change of signal, as measured by the optical probe, ensures flocculation is in progress. The start of flocculation can be detected
unambiguously when the sample contains at least 1 % mass asphaltenes as measured by Test Method D6560.
NOTE 2—This test method is applicable to products typical of Specification D396—Grades 5L, 5H, and 6, and Specification D2880—Grades 3-GT and
4-GT.
1.3 This test method was evaluated in an interlaboratory study in the nominal range of 32 to 76 for the maximum flocculation
ratio and in the nominal range of 36 to 95 for peptizing power.
NOTE 3—The nominal range is determined by (min. sample mean—Reproducibility) to (max. sample mean + Reproducibility).
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
2. Referenced Documents
2.1 ASTM Standards:
D396 Specification for Fuel Oils
D2880 Specification for Gas Turbine Fuel Oils
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4870 Test Method for Determination of Total Sediment in Residual Fuels
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
D6560 Test Method for Determination of Asphaltenes (Heptane Insolubles) in Crude Petroleum and Petroleum Products
D6792 Practice for Quality System in Petroleum Products and Lubricants Testing Laboratories
3. Terminology
3.1 Definitions:
3.1.1 asphaltenes, n—(rarely used in the singular), in petroleum technology, represent an oil fraction that is soluble in a specified
aromatic solvent but separates upon addition of an excess of a specified paraffinic solvent.
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
D02.14 on Stability and Cleanliness of Liquid Fuels.
Current edition approved Nov. 1, 2012Dec. 1, 2014. Published March 2013February 2015. Originally approved in 2004. Last previous edition approved in 20092012 as
D7060D7060 – 12.–09. DOI: 10.1520/D7060-12.10.1520/D7060-12R14.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 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 the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7060 − 12 (2014)
3.1.1.1 Discussion—
In this test method, the aromatic solvent is 1-methylnapthalene, and the paraffinic solvent is n-hexadecane.
3.1.2 compatibility, n— of crude oils or of heavy fuel oils, the ability of two or more crude oils or fuel oils to blend together
within certain concentration ranges without evidence of separation, such as the formation of multiple phases.
3.1.2.1 Discussion—
Incompatible heavy fuel oils or crude oils, when mixed or blended, result in the flocculation or precipitation of asphaltenes. Some
oils may be compatible within certain concentration ranges in specific mixtures, but incompatible outside those ranges.
3.1.3 flocculation, n— of asphaltenes from crude oils or heavy fuel oils, the aggregation of colloidally dispersed asphaltenes into
visibly larger masses which may or may not settle.
3.1.4 peptization, n— of asphaltenes in crude oils or heavy fuel oils, the dispersion of asphaltenes to produce a colloidal
dispersion.
3.1.5 stability reserve, n— in petroleum technology, the property of an oil to maintain asphaltenes in a peptized state and prevent
flocculation of the asphaltenes.
3.1.5.1 Discussion—
An oil with a low stability reserve is likely to undergo flocculation of asphaltenes when stressed (for example, extended heated
storage) or blended with a range of other oils. Two oils each with a high stability reserve are likely to maintain asphaltenes in a
peptized state and not lead to flocculation when blended together.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 critical cetane dilution, n—number of millilitres of cetane with which 1 g of undiluted sample can be diluted until it just
does not flocculate the asphaltenes.
3.2.2 critical dilution, n—number of millilitres of 1-methylnaphthalene and cetane with which 1 g of undiluted sample can be
diluted until it just does not flocculate the asphaltenes.
3.2.2.1 Discussion—
The number of millilitres of 1-methylnaphthalene and cetane is variable and depends on the ratio of sample to 1-methylnaphthalene
at the starting point and the sample type.
3.2.3 flocculation ratio, n—percentage by volume of 1-methylnaphtalene in a mixture of 1-methylnaphthalene and cetane.
3.2.4 flocculation ratio at critical dilution, n—percentage by volume of 1-methylnaphthalene in a mixture of
1-methylnaphthalene and cetane at the inflection point.
3.2.5 inflection point, n—last step during the titration with cetane, where flocculation of asphaltenes is not detected by the
optical probe as a significant and sustained increase in rate-of-change of signal.
3.2.6 maximum flocculation ratio, n—of asphaltenes, minimum required solvency power, expressed as percentage by volume
of 1-methylnaphthalene in a mixture of 1-methylnaphthalene and cetane, to keep the asphaltenes in a colloidal solution.
3.2.6.1 Discussion—
Maximum flocculation ratio is the flocculation ratio at extrapolated infinite dilution of the sample.
3.2.7 oil medium, n—that portion of a sample of heavy fuel oil or crude oil that surrounds and colloidally disperses the
asphaltenes.
3.2.7.1 Discussion—
For purposes of this test method, an oil sample is considered to be composed of an oil medium (sometimes called an oil matrix
or maltenes) and asphaltenes.
3.2.8 peptizing power, n—available solvency power, expressed as percentage by volume of 1-methylnaphthalene in a mixture
of 1-methylnaphthalene and cetane, to keep asphaltenes in a colloidal solution.
3.2.9 reciprocal dilution, n—dilution ratio of sample in solvent mixture of 1-methylnaphthalene and cetane.
D7060 − 12 (2014)
3.3 Symbols:
FR = maximum flocculation ratio
max
FR = flocculation ratio at critical dilution
x
Po = peptizing power
Xmin = critical cetane dilution
Xc = critical dilution
4. Summary of Test Method
4.1 Six portions of the sample are diluted in various ratios with 1-methylnaphthalene. Each solution is inserted into the
automatic apparatus, and titrated with cetane until flocculation of asphaltenes is detected by the optical probe. The first two
solutions are titrated with cetane in coarse determinations in which the flocculation ratio is decreased in 5 % steps. The coarse
determinations help to establish suitable starting values for the fine determinations, in which the flocculation ratio is decreased in
1 % steps. The four flocculation ratios at critical dilution, measured during the fine determinations, are used to calculate the
maximum flocculation ratio of the sample’s asphaltenes and the peptizing power of the sample’s oil medium.
5. Significance and Use
5.1 Asphaltenes are naturally occurring materials in crude petroleum and petroleum products containing residual material. The
asphaltenes are usually present in colloidal suspensions, but they may agglomerate and flocculate if the suspension of asphaltene
molecules is disturbed through excess stress or incompatibility. This test method provides compatibility parameters, which can be
used to assess stability reserve and compatibility.
3,4
5.2 A blend is considered stable when the blend’s peptizing power is higher than the blend’s maximum flocculation ratio; both
of them can be calculated using empirical blend rules. Refineries and terminal owners can prevent the flocculation of asphaltenes
due to incompatibility by assessing the compatibility of fuels beforehand.
NOTE 4—See Appendix X1 for an example of prediction of compatibility.
6. Interferences
6.1 High content of insoluble inorganic matter (sediment) has some interference in this test method. In this case, the insoluble
matter shall be removed by filtration according to Test Method D4870.
6.2 The presence of wax, present in paraffinic crudes or fuels from such crudes, does not interfere.
7. Apparatus
7.1 Integrated Automated Analytical Measurement System—This test method uses an integrated automated analytical
measurement system comprised of a PC–based computer and two titration stations (Fig. 1). See Annex A1 for detailed
information.
7.2 The computer controls test sequencing, acquires and accumulates optical probe signal data, provides processing
calculations, and automatically produces a report of important test parameters. The computer is capable of controlling one or two
independent titration stations.
7.3 Each titration station consists of the following:
7.3.1 Automatic titration unit,
7.3.2 Heater,
7.3.3 Magnetic stirrer,
7.3.4 Optical probe, and
7.3.5 Reaction cell plus lid.
7.4 Magnetic Stirrer/Hotplate, thermostatically controlled.
7.5 Stirring Bar, magnetic, PFTE-coated, 25 mm in length.
8. Reagents and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
Berryman, T. J., and Lewis, C. P. G., “The Stability of Residual Fuels. Theory and Practice of the Shell Concept,” 16th CIMAC Conference, Oslo, 1985.
Berg van den, F. G. A., “Developments in Fuel Oil Blending,” IASH 7th International Conference, Graz, Austria, 2000.
The sole source of supply of the apparatus known to the committee at this time is Automated Stability Analyser, (User Manual, Version 2), available from Zematra, 3194
DG Hoogvliet, The Netherlands. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive
careful consideration at a meeting of the responsible technical committee, which you may attend.
D7060 − 12 (2014)
FIG. 1 Titration Stations of Integrated Automated Analytical Measurement System
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
8.2 Asphaltene Solution (3 g/L) —Dissolve 0.15 g of dry asphaltenes in 1-methylnaphthalene and dilute to 50 mL. A procedure
to obtain asphaltenes is described in Appendix X2. Prepare fresh daily, as needed.
8.3 Cetane (n-Hexadecane). (Warning—Irritating to respiratory system and skin.)
8.4 Cleaning Solvent, technical grade, 95 % purity, for cleaning. It consists of one of the following:
8.4.1 Tetrahydrofuran, stabilized. (Warning—Extremely flammable. Irritating to eyes and respiratory system.)
8.4.2 Toluene. (Warning—Flammable. Health Hazard.)
8.4.3 Xylene. (Warning—Flammable. Harmful by inhalation and in contact with skin. Irritating to skin.)
8.5 n-Heptane. (Warning—Flammable. Vapor harmful. Vapor may cause flash fire.)
8.6 1-Methylnaphthalene. (Warning—Harmful if swallowed. Irritating to skin.)
8.7 Quality Control (QC) Sample, a stable and homogeneous residual fuel oil. The QC sample contains at least 1 mass %
asphaltenes and has approximate viscosities in the range of 180 to 380 mm /s at 50°C.
9. Sampling and Test Specimens
9.1 Sampling:
9.1.1 Obtain samples in accordance with Practices D4057 or D4177.
9.1.2 Samples of very viscous materials may be warmed until they are reasonably fluid before they are sampled.
9.1.3 Store samples prior to taking test specimens at ambient temperatures.
9.2 Test Specimen Preparation:
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 Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D7060 − 12 (2014)
9.2.1 Sample Fuel Temperature—Warm viscous samples until they can be mixed readily before opening the storage container.
For fuels with a high wax content (high pour point) the temperature shall be at least 15°C above the pour point.
9.2.2 Shake or mix the sample thoroughly. If the sample contains a high content of insoluble matter, filter the sample through
a 47-mm diameter glass fiber filter medium (such as Whatman Grade GF/A) using the Test Method D4870 filtration apparatus.
9.2.3 Preparation of Six Specimen Blends—Visually check the reaction cell and the lid for cleanliness. Dissolve specimen in
1-methylnaphthalene in several different ratios of solvent according
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