Blending rules
- Last UpdatedAug 14, 2026
- 1 minute read
The following table describes the blending rules used within the product for selected properties.
|
Property |
Blending rule |
|---|---|
|
Pour point |
exp(0.03*X) by volume, where X is value in Fahrenheit. |
|
Cloud point |
exp(0.035*X) by volume, where X is value in Fahrenheit. |
|
Freeze point |
exp(2.35+0.03638*X) by volume, where X is value in Fahrenheit. |
|
Viscosity (Kinematic) |
Linear as refutas. |
|
Molecular weight |
Linear as g/mol. |
|
Reid Vapour Pressure |
X^1.25 by volume, where X is value in psi. |
|
Flash point |
10^(-6.1188+4345.2/(X+383)) by volume, where X is value in Fahrenheit. |
|
Aniline point |
exp(0.003652*X) by volume, where X is a value expressed in Fahrenheit. |
|
Penetration |
log10(X+1.0e-6) by weight, where X is value in mm/10. |
|
Smoke point |
1/(X+0.001) by volume, where X is value in mm. |
In general, for other properties, these rules are followed:
-
Quantities measured in weight units (for example, paraffin content by weight) blend by weight.
-
Quantities measured in volume units (for example, paraffin content by volume) blend by volume.
-
Quantities measured in weight or volume units (for example, pure components) blend by weight or volume.
-
Correlated properties are computed from other property values for the product.
Tip Blending rules for properties can also be reviewed using the property manager. The property manager can also be used to review whether the cut property values blend back to the whole crude value. See Choosing Blending Behaviour in Add a new property.