1、Designation: D2501 14Standard Test Method forCalculation of Viscosity-Gravity Constant (VGC) ofPetroleum Oils1This standard is issued under the fixed designation D2501; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the calculation of the viscosity-gravity constant (VGC) of petroleum oils2having viscosities in
3、excess of 5.5 mm2/s at 40C (104F) and in excess of 0.8mm2/s at 100C (212F).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 asstandard. No other units of measurement are included in thisstand
4、ard.1.3.1 The SI unit of kinematic viscosity is mm2/s.1.3.2 ExceptionFahrenheit temperature units are used inthis practice because they are accepted by industry for the typeof legacy conversions described in this practice.1.4 This standard does not purport to address all of thesafety concerns, if an
5、y, 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 prior to use.2. Referenced Documents2.1 ASTM Standards:3D287 Test Method for API Gravity of Crude Petroleu
6、m andPetroleum Products (Hydrometer Method)D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD2140 Pract
7、ice for Calculating Carbon-Type Compositionof Insulating Oils of Petroleum OriginD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD7042 Test Method for Dynamic Viscosity and Density ofLiquids by Stabinger Viscometer (and the Calculation ofKinematic V
8、iscosity)3. Summary of Test 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 c
9、onstant is calculated from 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
10、 and is related to a fluids 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
11、 be indiscriminately applied 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 D445 or D7042. However, if thesample is extremely
12、 viscous or if it is otherwise inconvenientto measure the viscosity at 40C, the viscosity at 100C may bedetermined.5.2 Determine the density at 15C in accordance with TestMethod D1298, D4052,orD7042. Equivalent results can beobtained by determining API Gravity at 60F (15.56C) inaccordance with Test
13、Method D287, and converting the result1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0K on Correlative Methods.Current edition approved June 1, 2014. Published July 2014. Orig
14、inally approvedin 1966. Last previous edition approved in 2011 as D2501 11. DOI: 10.1520/D2501-142Coats, 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, orcontact ASTM Customer Service at servicea
15、stm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United St
16、ates1to density at 15C by means of Table 3 of the PetroleumMeasurement Tables (American Edition).4NOTE 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
17、 has beenexcluded.6. Calculation of Viscosity-Gravity Constant6.1 From Kinematic Viscosity at 40C and Density at15CUse the following equation to calculate the VGC fromthe measured properties:NOTE 2The original formulae2used Saybolt Universal Seconds andspecific gravity as the input parameters. The f
18、ormulae were later trans-formed to use kinematic viscosity in excess of 4 mm2at 40C and densityas input parameters and further revised to use kinematic viscosity inexcess of 5.5 mm2, all while keeping the original concepts of the formulaeintact.VGC 5G 2 0.0664 2 0.1154 LogV 2 5.5!0.94 2 0.109 LogV 2
19、 5.5!(1)where:G = density at 15C, g/mL, andV = kinematic viscosity at 40C, mm2/s.6.2 From Kinematic Viscosity at 100C and Density at15CUse the following equation to calculate the VGC:VGC 5G 2 0.108 2 0.1255 LogV20.8!0.90 2 0.097 LogV20.8!(2)where:G = density at 15C, g/mL, andV = kinematic viscosity
20、at 100C, mm2/s.7. Report7.1 Report the calculated VGC to the nearest .002 unit.7.2 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. Preci
21、sionlimits are not assigned to this calculation.8.2 The precision and bias for this test method for calculat-ing VGC are essentially as specified in Test Methods D287,D445, D1298, D4052, and D7042, and Practice D2140. Theprecision can be calculated as follows:8.2.1 For viscosity measured at 40C,rY51
22、0.94 2 0.109 log10V 2 5.5!(3)rG21rV20.00224 Y 2 1.059!2V 2 5.5!2where:rY= precision of the VGC,rG= precision of the gravity from D287, D1298, D4052,orD7042rV= precision of the viscosity from D445 or D7042,V = measured viscosity, andY = VGC.8.2.2 For viscosity measured at 100C,rY510.90 2 0.097 log10V
23、 2 0.8!(4)rG21rV20.00177Y 2 1.294!2V 2 0.8!28.3 The VGC calculated from the 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
24、.95 VGC, the expected average differencewill be approximately 0.003 units. Whenever possible, it ispreferable to determine the VGC using Eq 1.8.4 BiasThe procedure in Test Method D2501 for calcu-lation of viscosity-gravity constant has no bias because thevalue of viscosity-gravity constant can be de
25、fined only in termsof a test method.8.5 The term viscosity-gravity constant is also used inPractice D2140, 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.
26、 Keywords9.1 aromatic; density; kinematic viscosity; paraffinic4Published jointly by, and available from, ASTM Headquarters and EnergyInstitute, 61 New Cavendish St., London W1M 8AP. Companion volumestheBritish Edition and the Metric Editionare also available. These tables supersedeall other similar
27、 tables previously published by either of these societies and theNational Bureau of Standards Circular C-410 and the supplement to Circular C-410.D2501 142ANNEX(Mandatory Information)A1. CALCULATION OF VISCOSITY-GRAVITY CONSTANT FROM SAYBOLT VISCOSITY AND RELATIVE DENSITY (SPE-CIFIC GRAVITY)A1.1 The
28、 calculation of viscosity-gravity constant (VGC)can also be calculated from viscosity in units of Sayboltseconds universal (SUS) and relative density (specific gravity).A1.2 From Saybolt Viscosity at 100F and Relative Density(Specific Gravity) 60/60FA1.2.1 Use the following equation to calculate the
29、 VGCfrom the measured properties:VGC 510G 2 1.0752 logV 2 38!10 2 logV 2 38!(A1.1)where:G = relative density (specific gravity) at 60/60F, andV = Saybolt Universal viscosity at 100F.A1.3 From Saybolt Viscosity at 210F and Relative Density(Specific Gravity) 60/60FA1.3.1 Use the following equation to
30、calculate the VGC:VGC 5G 2 0.1244 logV12 31!0.9255 2 0.0979 logV12 31!2 0.0839 (A1.2)where:G = relative density (specific gravity) at 60/60F, andV1= Saybolt Universal viscosity at 210F.A1.4 The viscosity-gravity constant calculated from theSaybolt viscosity at 210F can differ slightly from that calc
31、u-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 to 0.5 VGC, theexpected average difference will be approximately 0.003 units.Whenever possible, it is preferable to determine the VGC usingEq
32、 A1.1.APPENDIXX1. REVISION HISTORYX1.1 This current revision includes a change in Eq 1 and Eq2 in Section 6, Calculation of Viscosity-Gravity Constant.X1.1.1 During a revision change from D2501-87 andD2501-91 there was a change in units from SUS (SayboltUniversal Seconds) to the SI unit of viscosity
33、 mm2/s (cSt). Thisunit change necessitated a modification of the Scope (1.1) from“in excess of 40 Saybolt Universal Seconds (SUS) at 100F(37.79C)” to “in excess of 4 cSt.=4106m2/s at 40C(104F).” This change created a mathematical error of trying totake the log of a negative number in Eq 1 (in Sectio
34、n 6,Calculation of Viscosity-Gravity Constant) for V (KinematicViscosities) less than 5.5 cSt (mm2/s) and the Scope value inexcess of 4 cSt. (mm2/s). Consensus input to this discrepancywas to change the Scope from “in excess of 4 cSt.=4106m2/s at 40C” to “5.5 mm2/s at 40C (104F) and in excess of0.8
35、mm2/s at 100C (212F).” This change was made in theD2501-11 revision.X1.2 Expected Average Differences in Section 8.3X1.2.1 Section 8.3 (Precision and Bias) discusses the “sta-tistical evaluation of VGC data derived from equivalent vis-cosities at both 100F and 210F suggests that in the rangefrom abo
36、ut 0.80 to 0.95 VGC, the expected average differencewill be approximately 0.003 units.” Because no evaluation hasbeen performed in SI units, the retention of the English units(F) is retained.D2501 143SUMMARY OF CHANGESSubcommittee D02.04 has identified the location of selected changes to this standa
37、rd since the last issue(D2501 11) that may impact the use of this standard. (Approved June 1, 2014.)(1) Test Method D7042 added as alternative to Test MethodD445 or Test Method D4052.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any ite
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