ASTM D7157-12
(Test Method)Standard Test Method for Determination of Intrinsic Stability of Asphaltene-Containing Residues, Heavy Fuel Oils, and Crude Oils (n-Heptane Phase Separation; Optical Detection)
Standard Test Method for Determination of Intrinsic Stability of Asphaltene-Containing Residues, Heavy Fuel Oils, and Crude Oils (<emph type="ital">n</emph >-Heptane Phase Separation; Optical Detection)
SIGNIFICANCE AND USE
5.1 This test method describes a sensitive method for estimating the intrinsic stability of an oil. The intrinsic stability is expressed as S-value. An oil with a low S-value 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 S-value are likely to maintain asphaltenes in a peptized state and not lead to asphaltene flocculation when blended together.
5.2 This test method can be used by petroleum refiners to control and optimize the refinery processes and by blenders and marketers to assess the intrinsic stability of blended asphaltene-containing heavy fuel oils.
SCOPE
1.1 This test method covers a procedure for quantifying the intrinsic stability of the asphaltenes in an oil by an automatic instrument using an optical device.
1.2 This test method is applicable to residual products from thermal and hydrocracking processes, to products typical of Specifications D396 Grades No. 5L, 5H, and 6, and D2880 Grades No. 3-GT and 4-GT, and to crude oils, providing these products contain 0.5 mass% or greater concentration of asphaltenes (see Test Method D6560).
1.3 This test method quantifies asphaltene stability in terms of state of peptization of the asphaltenes (S-value), intrinsic stability of the oily medium (So) and the solvency requirements of the peptized asphaltenes (Sa).
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: D7157 − 12
Standard Test Method for
Determination of Intrinsic Stability of Asphaltene-Containing
Residues, Heavy Fuel Oils, and Crude Oils (n-Heptane
1
Phase Separation; Optical Detection)
This standard is issued under the fixed designation D7157; 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* Products, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and
1.1 This test method covers a procedure for quantifying the
Petroleum Products
intrinsic stability of the asphaltenes in an oil by an automatic
D4870 Test Method for Determination of Total Sediment in
instrument using an optical device.
Residual Fuels
1.2 This test method is applicable to residual products from
D6560 Test Method for Determination ofAsphaltenes (Hep-
thermal and hydrocracking processes, to products typical of
tane Insolubles) in Crude Petroleum and Petroleum Prod-
Specifications D396 Grades No. 5L, 5H, and 6, and D2880
ucts
Grades No. 3-GT and 4-GT, and to crude oils, providing these
D6792 Practice for Quality System in Petroleum Products
products contain 0.5 mass% or greater concentration of as-
and Lubricants Testing Laboratories
phaltenes (see Test Method D6560).
1.3 This test method quantifies asphaltene stability in terms 3. Terminology
of state of peptization of the asphaltenes (S-value), intrinsic
3.1 Definitions:
stabilityoftheoilymedium(So)andthesolvencyrequirements
3.1.1 For definitions of some terms used in this test method,
of the peptized asphaltenes (Sa).
refer to Terminology D4175.
1.4 The values stated in SI units are to be regarded as 3.1.2 asphaltenes, n—(rarely used in the singular), in petro-
standard. No other units of measurement are included in this leum technology, represent an oil fraction that is soluble in a
standard. specified aromatic solvent but separates upon addition of an
excess of a specified paraffinic solvent.
1.5 This standard does not purport to address all of the
3.1.2.1 Discussion—In this test method, the aromatic sol-
safety concerns, if any, associated with its use. It is the
vent is toluene and the paraffinic solvent is n-heptane.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.1.3 compatibility, n—of crude oils or of heavy fuel oils,
bility of regulatory limitations prior to use the ability of two or more crude oils or fuel oils to blend
together within certain concentration ranges without evidence
2. Referenced Documents
of separation, such as the formation of multiple phases.
2
3.1.3.1 Discussion—Incompatible heavy fuel oils or crude
2.1 ASTM Standards:
oils, when mixed or blended, result in the flocculation or
D396 Specification for Fuel Oils
precipitation of asphaltenes. Some oils may be compatible
D2880 Specification for Gas Turbine Fuel Oils
within certain concentration ranges in specific mixtures, but
D4057 Practice for Manual Sampling of Petroleum and
incompatible outside those ranges.
Petroleum Products
D4175 Terminology Relating to Petroleum, Petroleum
3.1.4 flocculation, n—of asphaltenes from crude oils or
heavy fuel oils, the aggregation of colloidally dispersed as-
phaltenes into visible larger masses which may or may not
1
This test method is under the jurisdiction of Committee D02 on Petroleum
settle.
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
mittee D02.14 on Stability and Cleanliness of Liquid Fuels.
3.1.5 peptization, n—of asphaltenes in crude oils or heavy
Current edition approved Nov. 1, 2012. Published February 2013. Originally
oils, the dispersion of asphaltenes to produce a colloidal
approved in 2005. Last previous edition approved in 2009 as D7157–09. DOI:
dispersion.
10.1520/D7157-12.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.6 stability reserve, n—in petroleum technology, the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
property of an oil to maintain asphaltenes in a peptized state
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. and prevent flocculation of asphaltenes.
*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
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D7157 − 12
3.1.6.1 Discussion—An oil with a low stability reserve is 4. Summary of Test Method
likelytoundergoflocculationofasphalteneswhenstressed(for
4.1 Thistestmethodusesanintegratedautomatedanalyt
...
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: D7157 − 09 D7157 − 12 An American National Standard
Standard Test Method for
Determination of Intrinsic Stability of Asphaltene-Containing
Residues, Heavy Fuel Oils, and Crude Oils (n-Heptane
1
Phase Separation; Optical Detection)
This standard is issued under the fixed designation D7157; 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*
1.1 This test method covers a procedure for quantifying the intrinsic stability of the asphaltenes in an oil by an automatic
instrument using an optical device.
1.2 This test method is applicable to residual products from thermal and hydrocracking processes, to products typical of
Specifications D396 Grades No. 5L, 5H, and 6, and D2880 Grades No. 3-GT and 4-GT, and to crude oils, providing these products
contain 0.5 mass% or greater concentration of asphaltenes (see Test Method D6560).
1.3 This test method quantifies asphaltene stability in terms of state of peptization of the asphaltenes (S-value), intrinsic stability
of the oily medium (So) and the solvency requirements of the peptized asphaltenes (Sa).
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
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
D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4870 Test Method for Determination of Total Sediment in Residual Fuels
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 For definitions of some terms used in this test method, refer to Terminology D4175.
3.1.2 asphaltene,asphaltenes, n—(rarely used in the singular), in petroleum technology, a molecule of high molecular mass, high
carbon/hydrogen ratio, and containing hetero-atoms.represent an oil fraction that is soluble in a specified aromatic solvent but
separates upon addition of an excess of a specified paraffinic solvent.
1
This test method is under the jurisdiction of Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.14 on Stability
and Cleanliness of Liquid Fuels.
Current edition approved June 1, 2009Nov. 1, 2012. Published July 2009February 2013. Originally approved in 2005. Last previous edition approved in 20052009 as
D7157–05.–09. DOI: 10.1520/D7157-09.10.1520/D7157-12.
2
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.
3.1.2.1 Discussion—
Asphaltenes are found largely in crude oils and in heavy fuel oils containing residual fractions. They are insoluble in alkanes such
*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
1
---------------------- Page: 1 ----------------------
D7157 − 12
as In this test method, the n-heptane and cetane, but soluble in aromatic solvents such as benzene, toluene, and
1-methylnaphthalene. aromatic solvent is toluene and the paraffinic solvent is n-heptane.
3.1.3 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.
3.1.3.1 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 incom
...
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