GB/T 8023-1987 Viscosity-temperature calculation chart for liquid petroleum products

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1. Method number / full name / English name / replacement relationship

• Standard number: GB 8023-87
• Chinese name: Viscosity-temperature calculation chart for liquid petroleum products
• English name: Liquid petroleum products—Viscosity-temperature charts
• UDC: 865.7:532.77 (083.5)
• Replacement relationship: not provided in the available source
• Approval/implementation: approved by China Petrochemical Corporation 1987-05-12, implemented on 1988-05-01
• Drafting unit: Research Institute of Petroleum Processing (the extracted name of the drafting organization is garbled; requires confirmation against the source standard (source-text extraction))
• Main drafter: Yang Miefu (requires confirmation against the source standard (source-text extraction))
• Reference relationship: reference ASTM D341 (the original text “ASTN D31-T7L98eN” is source-text extraction noise, requires confirmation against the source standard (source-text extraction))

2. Applicable scope and non-applicability

• Applicable: liquid petroleum products or pure liquid hydrocarbons that are in a homogeneous state within the specified range, which lies between the cloud point and the initial boiling point of the liquid petroleum.
• Use: calculation of kinematic viscosity-temperature data for liquid petroleum products; within the specified range, a straight line can be plotted; when the kinematic viscosities of a liquid at two temperatures are known, the kinematic viscosity of that liquid at other temperatures can be determined.
• Non-applicable/unreliable situations:
  • For kinematic viscosity data obtained at temperatures below the cloud point or above the initial boiling point, interpolation or extrapolation using this standard cannot give reliably repeatable results.
  • Extrapolating from a low-temperature region to a high-temperature region, or from a high-temperature region to a low-temperature region, to determine the corresponding kinematic viscosity will produce relatively large errors.
• Supplementary note: kinematic viscosity data obtained according to this standard at low viscosity or high temperature (such as above 300°C) still have a good linear relationship and can be used to draw a reliable viscosity-temperature straight line.

3. Method principle

• The kinematic viscosity-temperature data of liquid petroleum products can be plotted as a straight line within the specified range.
• The viscosity-temperature calculation charts provided by this standard are designed to allow the kinematic viscosity-temperature data of liquid petroleum products or fractions and general pure liquid hydrocarbon substances to be plotted as a straight line on the chart.
• Draw a very thin straight line through two points; within the specified range, the kinematic viscosity value of the liquid at any temperature, or the temperature corresponding to a given kinematic viscosity, can be obtained by interpolation from the straight line.
• Appendix A gives the general viscosity-temperature equation (mathematical relationship), and Appendix B gives the calculation of the volume fraction of component oils in a blended oil.

4. Reagents and materials (purity / preparation)

not provided in the available source.

5. Instruments and equipment

not provided in the available source (the main text of the standard does not list clauses on instruments and equipment; the calculation chart and ruler measurement are mentioned in Appendix B graphical method as “measure with a ruler”).

6. Recommended operating conditions

• Selection of calculation charts (2.2):
  • When plotting requirements are more convenient and accurate, Chart 1 and Chart 3 are more suitable.
  • Chart 4 and Chart 5 are drawn to a reduced scale from Chart 1 and Chart 2 only for reporting or rapid calculation needs.
• Ranges of the five charts (2.1):
  • Chart 1 Viscosity-temperature chart for liquid petroleum products (high range): kinematic viscosity 0.3–20000000 mm²/s; temperature -70–370°C.
  • Chart 2 Viscosity-temperature chart for liquid petroleum products (low range): kinematic viscosity 0.18–500 mm²/s; temperature -70–370°C.
  • Chart 3 Viscosity-temperature chart for liquid petroleum products (medium range): kinematic viscosity 3.0–20000 mm²/s; temperature -40–150°C.
  • Chart 4 Small-size viscosity-temperature chart for liquid petroleum products (high range): kinematic viscosity 0.3–20000000 mm²/s; temperature -70–370°C.
  • Chart 5 Small-size viscosity-temperature chart for liquid petroleum products (low range): kinematic viscosity 0.18–500 mm²/s; temperature -70–370°C.
• Note: The above five charts are provided by the Fifth Laboratory of the Research Institute of Petroleum Processing.

7. Sampling and sample preparation

not provided in the available source.

8. Analytical procedure

• 3 Kinematic viscosity calculation procedure (the extracted procedure heading is garbled; requires confirmation against the source standard (source-text extraction)):
  • Draw a very thin straight line through two points; within the specified range, the kinematic viscosity value of the liquid at any temperature, or the temperature corresponding to a given kinematic viscosity, can be obtained by interpolation from the straight line.
  • Note: When two viscosity-temperature points of the liquid petroleum are unknown, their kinematic viscosities at two temperatures can be determined according to GB 26 “Determination of Kinematic Viscosity of Petroleum Products”.
• 4 Extrapolated kinematic viscosity calculation:
  • Within the specified range, if the known viscosity-temperature points of the liquid petroleum are accurate, then the viscosity-temperature points on the extrapolated portion of the viscosity-temperature straight line are likewise satisfactory. Therefore, the kinematic viscosity of the liquid at any temperature can be read from the extrapolated line.
  • It should be noted that the two known viscosity-temperature points should be far apart. If these two points are too close, the measurement error of kinematic viscosity and the plotting error will seriously affect the accuracy of the extrapolated point. Generally speaking, the farther the extrapolated viscosity-temperature point is from the known viscosity-temperature points, the greater the error in the kinematic viscosity determined by extrapolation will be. This is especially so when the difference between the extrapolation temperature and the temperature of the nearest known viscosity-temperature point is greater than the temperature difference between the two known viscosity-temperature points. In this case, it is more appropriate to additionally determine the kinematic viscosity at a third temperature as a known viscosity-temperature point, so that it is closer to the extrapolated viscosity-temperature point.

9. Qualitative and quantitative and calculation formulas

• Definition (1): viscosity-temperature point — the kinematic viscosity value possessed by a liquid petroleum product at a certain temperature. The kinematic viscosity of a viscosity-temperature point is expressed in mm²/s, and the temperature is expressed in °C.
• Appendix A Mathematical relationship (supplementary document):
  • A.1 The general viscosity-temperature equation for liquid petroleum products was obtained by computer processing based on measured kinematic viscosity-temperature data of 17 jet fuels, 16 diesel fuels, 152 lubricating oil fractions or products, and 3 pure liquid hydrocarbons.
  • A.2 General mathematical formula:
    • loglogZ = b + m logT … (A1)
    • Z = 1 + 0.65 + C … (A2) (thus in the original text, requires confirmation against the source standard (source-text extraction))
    • C = EXP (-1.214 - 1.742 - 0.4802) … (A3) (thus in the original text, requires confirmation against the source standard (source-text extraction))
    • Where: ν—— is the kinematic viscosity of the liquid petroleum product at T degrees, mm²/s; T—— is temperature, K; b and m—— are constants; EXP—— is a mathematical symbol indicating that the quantity in the following parentheses should be regarded as the exponent of e, and e is 2.71828.
  • A.3 Simple mathematical formula: In formulas (A1~A3), when ν is greater than 2 mm²/s, the C term can be omitted, giving:
    • loglog (ν + 0.65) = b + m logT … (A4)
    • This equation can meet the kinematic viscosity calculation needs of most liquid petroleum products. The constants b and m can be obtained from two known viscosity-temperature points of the petroleum liquid. The kinematic viscosity at any other point can then be calculated.
  • A.4 Equation application range:
    • ν, mm²/s: 2.00~2×10⁷ (the original text “2 ×10” requires confirmation against the source standard (source-text extraction))
    • ν+0.65: 0.18~2×10⁷ (the original text “2×10?” requires confirmation against the source standard (source-text extraction))
• Appendix B Calculation of volume fraction of component oils in blended oil (supplementary document):
  • B.1 When two component oils are blended so that they reach a certain required kinematic viscosity at a given temperature, the viscosity-temperature chart for liquid petroleum products can be used for this type of calculation to predict the respective volume fractions of the two component oils. This calculation allows the component oils themselves to differ in type, molecular weight, and viscosity index. Therefore, it is a relatively good calculation method. Especially when the viscosity indices and types of the component oils differ significantly, the results are still relatively accurate.
  • B.2 Calculation conditions: the kinematic viscosity values of each component oil at 40°C and 100°C are known, and the kinematic viscosity value of the blended oil at the required temperature (such as 40°C or 100°C) is given.
  • B.3 Two calculation methods:
    • B.3.1 Graphical method: plot the known kinematic viscosity-temperature data of the two component oils respectively on the standard viscosity-temperature chart for liquid petroleum products, and draw two straight lines through these points respectively (such as L, H in the figure); these straight lines should be extended beyond the given kinematic viscosity value of the blended oil. On the chart, through the given kinematic viscosity value of the blended oil, draw a straight line PQ parallel to the temperature coordinate, so that it passes through the viscosity-temperature lines L and H of the two component oils. Use a ruler to measure the distance along this line between the two component oil viscosity-temperature lines, then on this line measure the distance from the viscosity-temperature line of the low-viscosity component oil to the required temperature coordinate; divide the latter by the former to obtain the volume fraction of the high-viscosity component oil.
    • Example (B.3.1):
      • Known high-viscosity component oil H: ν40 = 439.6 mm²/s; ν100 = 32.34 mm²/s
      • Known low-viscosity component oil L: ν40 = 28.96 mm²/s; ν100 = 5.090 mm²/s
      • It is desired that after blending these two oils, the viscosity at temperature 40°C is 173.6 mm²/s; calculate the volume fraction of the high-viscosity component oil.
      • On the standard viscosity-temperature chart for liquid petroleum products (such as schematic diagram 3), draw the viscosity-temperature line H of the high-viscosity component oil and the viscosity-temperature line L of the low-viscosity component oil. Along 173.6 mm²/s, draw a straight line PQ parallel to the temperature coordinate. On this straight line, the measured distance between the two viscosity-temperature lines is 62.5 mm, and the measured distance from the viscosity-temperature line of the low-viscosity component oil to the required temperature coordinate is 42.5 mm.
      • Volume fraction of the high-viscosity component oil = 42.5 / 62.5 = 0.68
      • Volume fraction of the low-viscosity component oil = 1 - 0.68 = 0.32
    • B.3.2 Calculator calculation method:
      • Relationship at 40°C: volume fraction of the high-viscosity component oil = … (B1)
      • Relationship at 100°C: volume fraction of the high-viscosity component oil = (E-F)(A-C)/… (B2) (the original formula layout is incomplete, requires confirmation against the source standard (source-text extraction))
      • Where:
        • A = -loglogZ_B (40)
        • B = -loglogZ_B (100)
        • C = -loglogZ_L (40)
        • D = -loglogZ_L (100)
        • E = -loglogZ_H (40)
        • F = -loglogZ_H (100)
        • Z = (ν + 0.65)
        • The subscript B—— denotes the blended oil; the subscript L—— denotes the low-viscosity component oil; the subscript H—— denotes the high-viscosity component oil; the subscript (40) — denotes 40°C; the subscript (100) — denotes 100°C.
      • Example 2 Using the known data listed in B.3.1, calculated according to relationship (B1):
        • A = 0.3505
        • C = 0.1677
        • E = 0.4222
        • D = -0.1198
        • F = 0.1814
        • Volume fraction of the high-viscosity component oil = 0.681 (the intermediate calculation source-text extraction in the original text is incomplete, requires confirmation against the source standard (source-text extraction))
  • B.4 It is also permissible to use it for calculations at other temperatures. If the kinematic viscosity-temperature data must be extrapolated to above or below the viscosity-temperature points of the known component oils, the accuracy of the calculation results will be reduced.

10. Precision

Not provided in the available source (the main text does not list precision clauses; it only mentions qualitative descriptions of measurement error, plotting error, and extrapolation error).

11. Report

Not provided in the available source.

12. Reference documents

• GB 26 "Petroleum Products — Determination of Kinematic Viscosity" (cited in the note to Section 3 of the main text)
• ASTM D341 (the original "ASTN D31-T7L98eN" is source-text extraction noise, requires confirmation against the source standard (source-text extraction); mentioned for reference in the additional notes)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Q&A Reference