ASTM D7112-05a
(Test Method)Standard Test Method for Determining Stability and Compatibility of Heavy Fuel Oils and Crude Oils by Heavy Fuel Oil Stability Analyzer (Optical Detection)
Standard Test Method for Determining Stability and Compatibility of Heavy Fuel Oils and Crude Oils by Heavy Fuel Oil Stability Analyzer (Optical Detection)
SIGNIFICANCE AND USE
Automatic determination of stability parameters using a light back-scattering technique improves accuracy and removes human errors. In manual testing, operators have to visually compare oil stains on pieces of filter paper to determine if asphaltenes have been precipitated.
Refinery thermal and hydrocracking processes can be run closer to their severity limits if stability parameters can be calculated more accurately. This gives increased yield and profitability.
Results from the test method could be used to set a standard specification for stability parameters for fuel oils.
The compatibility parameters of crude oils can be used in crude oil blending in refineries to determine, in advance, which crude oil blends will be compatible and thus can be used to minimize plugging problems, unit shut downs, and maintenance costs. Determination of crude oil compatibility parameters also enables refineries to select crude oil mixtures more economically.
This test method can measure stability and compatibility parameters, and determine stability reserve on different blends for particular applications to optimize the blending, storage, and use of heavy fuel oils
Note 1—Users of this test method would normally use stability and compatibility parameters to determine stability reserve of residual products, fuel blends and crude oils. However, the interpretation of stability, stability reserve and compatibility is heavily ‘use dependent,’ and is beyond the scope of this test method.
SCOPE
1.1 This test method covers an automated procedure involving titration and optical detection of precipitated asphaltenes for determining the stability and compatibility parameters of refinery residual streams, residual fuel oils, and crude oils. Stability in this context is the ability to maintain asphaltenes in a peptized or dissolved state and not undergo flocculation or precipitation. Similarly, compatibility relates to the property of mixing two or more oils without precipitation or flocculation of asphaltenes.
1.2 This test method is applicable to residual products from atmospheric and vacuum distillation, from thermal, catalytic, and hydrocracking processes, to products typical of Specifications D 396, Grades No. 5L, 5H, and 6, and D 2880, Grades No. 3-GT and 4-GT, and to crude oils, providing these products contain 0.05 mass % or greater concentration of asphaltenes.
1.3 This test method is not relevant to oils that contain less than 0.05 % asphaltenes, and would be pointless to apply to unstable oils that already contain flocculated asphaltenes.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information 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)
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Designation:D7112–05a
Standard Test Method for
Determining Stability and Compatibility of Heavy Fuel Oils
and Crude Oils by Heavy Fuel Oil Stability Analyzer (Optical
1
Detection)
This standard is issued under the fixed designation D7112; 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* D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers an automated procedure involv-
D4175 Terminology Relating to Petroleum, Petroleum
ing titration and optical detection of precipitated asphaltenes
Products, and Lubricants
for determining the stability and compatibility parameters of
D4177 Practice for Automatic Sampling of Petroleum and
refinery residual streams, residual fuel oils, and crude oils.
Petroleum Products
Stability in this context is the ability to maintain asphaltenes in
D6299 Practice for Applying Statistical Quality Assurance
a peptized or dissolved state and not undergo flocculation or
and Control Charting Techniques to Evaluate Analytical
precipitation. Similarly, compatibility relates to the property of
Measurement System Performance
mixingtwoormoreoilswithoutprecipitationorflocculationof
D6560 Test Method for Determination of Asphaltenes
asphaltenes.
(Heptane Insolubles) in Crude Petroleum and Petroleum
1.2 This test method is applicable to residual products from
Products
atmospheric and vacuum distillation, from thermal, catalytic,
and hydrocracking processes, to products typical of Specifica-
3. Terminology
tions D396, Grades No. 5L, 5H, and 6, and D2880, Grades No.
3.1 Definitions:
3-GT and 4-GT, and to crude oils, providing these products
3.1.1 For definitions of some terms used in this test method,
contain 0.05 mass % or greater concentration of asphaltenes.
such as crude oil, repeatability, reproducibility, and residual
1.3 This test method is not relevant to oils that contain less
fuel oil, refer to Terminology D4175.
than 0.05 % asphaltenes, and would be pointless to apply to
3.1.2 asphaltenes, n—in petroleum technology, molecules
unstable oils that already contain flocculated asphaltenes.
of high molecular mass, high carbon/hydrogen ratio, and
1.4 The values stated in SI units are to be regarded as
containing hetero-atoms.
standard. No other units of measurement are included in this
3.1.2.1 Discussion—Asphaltenes are generally found in
standard.
crude oils and in heavy fuel oils containing residual fractions.
1.5 This standard does not purport to address all of the
Their presence is determined by their insolubility in alkanes
safety concerns, if any, associated with its use. It is the
such as n-heptane and solubility in aromatics such as xylene.
responsibility of the user of this standard to establish appro-
3.1.3 compatibility, n—of crude oils and of heavy fuel oils,
priate safety and health practices and determine the applica-
the ability of two or more crude oils or fuel oils to be blended
bility of regulatory limitations prior to use.
together within specified ratios without evidence of separation,
2. Referenced Documents such as flocculation or separation of asphaltenes.
2
3.1.4 flocculation, n—of asphaltenes in crude oils or heavy
2.1 ASTM Standards:
fuel oils, the aggregation of colloidally dispersed asphaltenes
D396 Specification for Fuel Oils
into larger, visible masses that may or may not settle.
D2880 Specification for Gas Turbine Fuel Oils
3.1.5 stability reserve, n—of crude oils, heavy fuel oils, and
residual streams containing asphaltenes, the property of an oil
1
This test method is under the jurisdiction of ASTM Committee D02 on
to maintain asphaltenes in a peptized (colloidally dispersed)
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
state and prevent their flocculation when stored or when
D02.14 on Stability and Cleanliness of Liquid Fuels.
blended with other oils.
Current edition approved Nov. 1, 2005. Published November 2005. Originally
approved in 2005. Last previous edition approved in 2005 as D7112–05. DOI:
3.1.5.1 Discussion—An oil with a high stability reserve can
10.1520/D7112-05A.
be stored for a long period of time or blended with a range of
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
other oils without flocculation of asphaltenes.
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.
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