Chemical Components and Thermodynamic Methods

The first step in any process simulation is the definition of the chemical components involved and the selection of thermodynamic methods that may provide reliable values of k-values, enthalpy and other properties in the range of temperatures, pressures and composition encompassed by the process under study.

A component library with most common chemical components in the petrochemical industry is available.

The thermodynamic methods library is extremely rich as well as up-to-date. It contains a large number of methods (over 30 methods/models) for the calculation of thermodynamic (K-values, enthalpies, entropies, densities, etc.) and transport properties (viscosities, conductivities) of pure components and mixtures.

The user can modify component data or set up his own non-library components at the beginning of a simulation run.

XPSIM includes a number of correlations for the generation of thermodynamic properties of pseudo-components starting from NBP, density and molecular weight. It is also possible to automatically generate and characterize petroleum pseudo-components starting from ASTM or TBP distillation curves

On the calculation results, distillation curves are recalculated.

Equation of state

Standard cubic equation such as SRK and PR are implemented.
In addition BWRS and LK (Lee-kesler) models are available.


The GERG-2004 equation of state is now available. It can be applied for the calculation of natural gas and LNG systems


This equation of state can be used for the evaluation of the density of natural-gas systems.
This is congruent with the ISO-12213-2 guidelines