Properties
Function
Method – The program reads the ‘cp’ file and calculates its physical and thermodynamic properties. For those properties that are simple additive functions of the components, a weighted average is obtained. For properties that exhibit non-ideal behavior special programs are used to calculate the non-ideality. An example of this type of property is vapor pressure for which an activity coefficient is used to correct Raoult’s law vapor pressures. The same approach (under development) is expected to be successful with octane number, cetane number, viscosity, asphaltenes content, freeze and cloud point.
Use – Properties is used whenever the properties of a stream are required. This can be for off-line use or it can be embedded in applications such as Monitor, Assay, Troubleshoot and other programs for which control depends on properties. It may be possible to generalize the algorithms used in Monitor to build a function for inter-convertibility of properties.
Development Status – A program to report Assay properties is complete. Programs to report properties of non-ideal behavior must still be developed. However, the success achieved with developing activity coefficient calculators for use in Raoult’s law calculation suggests this task is feasible at not much cost.
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