1、Designation: D 2501 91 (Reapproved 2005)An American National StandardStandard Test Method forCalculation of Viscosity-Gravity Constant (VGC) ofPetroleum Oils1This standard is issued under the fixed designation D 2501; the number immediately following the designation indicates the year oforiginal ado
2、ption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the calculation of the viscosity-gravity const
3、ant (VGC) of petroleum oils2having viscosities inexcess of 4 cSt. = 4 3 106m2/s at 40C (104F).1.2 Annex A1 describes a method for calculating the VGCfrom Saybolt (SUS) viscosity and relative density.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses
4、are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prio
5、r to use.2. Referenced Documents2.1 ASTM Standards:3D 287 Test Method forAPI Gravity of Crude Petroleum andPetroleum Products (Hydrometer Method)D 445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and the Calculation of DynamicViscosity)D 1298 Test Method for Density, Relativ
6、e Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer MethodD 2140 Test Method for Carbon-Type Composition of In-sulating Oils of Petroleum OriginD 4052 Test Method for Density and Relative Density ofLiquids by Digital Density Meter3. Summary of Te
7、st Method3.1 The kinematic viscosity at 40C (104F) and the densityat 15C of the oil are determined. If the oil is extremelyviscous, or if it is otherwise inconvenient to determine theviscosity at 40C, the kinematic viscosity at 100C (212F) canbe used. The viscosity-gravity constant is calculated fro
8、m themeasured physical properties using the appropriate equation.4. Significance and Use4.1 The viscosity-gravity constant (VGC) is a useful func-tion for the approximate characterization of the viscous frac-tions of petroleum.2It is relatively insensitive to molecularweight and is related to a flui
9、ds composition as expressed interms of certain structural elements. Values of VGC near 0.800indicate samples of paraffinic character, while values close to1.00 indicate a preponderance of aromatic structures. Likeother indicators of hydrocarbon composition, the VGC shouldnot be indiscriminately appl
10、ied to residual oils, asphalticmaterials, or samples containing appreciable quantities ofnonhydrocarbons.5. Measurement of Physical Properties5.1 Preferably, determine the kinematic viscosity at 40C asdescribed in Test Method D 445. However, if the sample isextremely viscous or if it is otherwise in
11、convenient to measurethe viscosity at 40C, the viscosity at 100C may be deter-mined.5.2 Determine the density at 15C in accordance with TestMethod D 1298 or Test Method D 4052. Equivalent results canbe obtained by determining API Gravity at 60F (15.56C) inaccordance with Test Method D 287, and conve
12、rting the resultto density at 15C by means of Table 3 of the PetroleumMeasurement Tables (American Edition).41This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04 on Hydrocarbon Analysis.Current ed
13、ition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1966. Last previous edition approved in 2000 as D 2501 91 (2000).2Coats, H. B., and Hill, J. B., Industrial and Engineering Chemistry, Vol 20,1928, p. 641.3For referenced ASTM standards, visit the ASTM website, www.astm.org,
14、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Published jointly by, and available from, ASTM Headquarters and EnergyInstitute, 61 New Cavendish St., London W1M 8AP. Companion
15、volumestheBritish Edition and the Metric Editionare also available. These tables supersedeall other similar tables previously published by either of these societies and theNational Bureau of Standards Circular C-410 and the supplement to Circular C-410.1Copyright ASTM International, 100 Barr Harbor
16、Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 1If it is necessary to convert a result obtained using the digitaldensity meter to a density at another temperature, the Petroleum Measure-ment Tables can be used only if the glass expansion factor has beenexcluded.6. Calculati
17、on of Viscosity-Gravity Constant6.1 From Kinematic Viscosity at 40C and Density at15CUse the following equation to calculate the VGC fromthe measured properties:VGC 5G 2 0.0664 2 0.1154 LogV 2 5.5!0.94 2 0.109 LogV 2 5.5!(1)where:G = density at 15C, g/mL, andV = kinematic viscosity at 40C, cSt.6.2 F
18、rom Kinematic Viscosity at 100C and Density at15CUse the following equation to calculate the VGC:VGC 5G 2 0.108 2 0.1255 LogV8 2 0.8!0.90 2 0.097 LogV8 2 0.8!(2)where:G = density at 15C, g/mL, andV8 = kinematic viscosity at 100C, cSt.7. Report7.1 Report the calculated VGC to the nearest .002 unit.7.
19、2 If the viscosity at 100C was used for the calculation,state this in the report.8. Precision and Bias8.1 The calculation of viscosity-gravity constant from kine-matic viscosity at 40C and density at 15C is exact. Precisionlimits are not assigned to this calculation.8.2 The precision of the calculat
20、ed VGC is dependent onlyon the precision of the original determinations of viscosity anddensity. Those precision statements are found in their respec-tive test methods. The precision can be calculated as follows:8.2.1 For viscosity measured at 40C,rY510.94 2 0.109 log10V 2 5.5!(3)rG21 rV20.00224 Y 2
21、 1.059!2V 2 5.5!2where:rY= precision of the VGC,rG= precision of the gravity from D 287,rV= precision of the viscosity from D 445,V = measured viscosity, andY = VGC.8.2.2 For viscosity measured at 100C,rY510.90 2 0.097 log10V 2 0.8!(4)rG21 rV20.00177Y 2 1.294!2V 2 0.8!28.3 The VGC calculated from th
22、e viscosity at 100C candiffer slightly from that calculated from the viscosity at 40C.A statistical evaluation of VGC data derived from equivalentviscosities at both 100F and 210F suggests that in the rangefrom about 0.80 to 0.95 VGC, the expected average differencewill be approximately 0.003 units.
23、 Whenever possible, it ispreferable to determine the VGC using Eq 1.8.4 BiasThe procedure in Test Method D 2501 for calcu-lation of viscosity-gravity constant has no bias because thevalue of viscosity-gravity constant can be defined only in termsof a test method.8.5 The term viscosity-gravity consta
24、nt is also used in TestMethod D 2140, for determining carbon-type composition ofinsulating oils of petroleum origin. The equations used aredifferent from those in this test method; the bias between thetwo test methods is unknown.9. Keywords9.1 aromatic; density; kinematic viscosity; paraffinicANNEX(
25、Mandatory Information)A1. CALCULATION OF VISCOSITY-GRAVITY CONSTANT FROM SAYBOLT VISCOSITY AND RELATIVE DENSITY(SPECIFIC GRAVITY)A1.1 The calculation of viscosity-gravity constant (VGC)can also be calculated from viscosity in units of Sayboltseconds universal (SUS) and relative density (specific gra
26、vity).A1.2 From Saybolt Viscosity at 100F and Relative Density(Specific Gravity) 60/60FUse the following equation tocalculate the VGC from the measured properties:VGC 510G 2 1.0752 log V 2 38!10 2 log V 2 38!(A1.1)where:G = relative density (specific gravity) at 60/60F, andV = Saybolt Universal visc
27、osity at 100F.D 2501 91 (2005)2A1.3 From Saybolt Viscosity at 210F and Relative Density(Specific Gravity) 60/60FUse the following equation tocalculate the VGC:VGC 5G 2 0.1244 logV12 31!0.9255 2 0.0979 log V12 31!2 0.0839 (A1.2)where:G = relative density (specific gravity) at 60/60F, andV1= Saybolt U
28、niversal viscosity at 210F.A1.4 The viscosity-gravity constant calculated from theSaybolt viscosity at 210F can differ slightly from that calcu-lated from the 100F viscosity. A statistical evaluation of VGCdata derived from both the 100F and 210F viscositiessuggests that in the range from about 0.80
29、 to 0.5 VGC, theexpected average difference will be approximately 0.003 units.Whenever possible, it is preferable to determine the VGC usingEq A1.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
30、of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every fi
31、ve years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical
32、committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 2501 91 (2005)3
