CPA and sPC-SAFT in Process Simulators


  • To use CERE Cubic-Plus-Association (CPA) and simplified Perturbed-Chain-Statistical-Associating-Fluid-Theory (sPC-SAFT) equation of state (EoS) in any process simulator (through CAPE-OPEN platform).
  • To use CERE CPA equation of state in Aspen Plus (through User Model)


  • The CPA/sPC-SAFT is a rather recently developed model, and it is not available in commercial process simulators (CPA is available in latest version of Aspen Plus but for limited applications).

CERE has developed ThermoSystem, which is a CAPE-OPEN 1.0.0 compatible library containing the CPA and sPC‐SAFT EoS. ThermoSystem contains a parameter database containing recommended pure components and binary interaction parameters, and can be used as thermodynamic package in a process simulators through CAPE-OPEN standard maintained by the CO-LaN consortium.

The CAPE-OPEN standard specification presents a set of interfaces that enables communication between a CAPE-OPEN compliant process simulator and ThermoSystem, and it can be visualized in Figure 1.

In other words, one can use a user-defined thermodynamic property package (e.g., CPA) for process design instead of using built-in thermodynamic models (e.g., Peng−Robinson) available in process simulators.

As on today almost all of the process simulators, used by various industries, support the CAPE-OPEN standard interface. ThermoSystem supports only two phase PT flash but can use the built-in flash from the process simulator (in this case, the HYSYS Flash).

  • ThermoSystem also contains the CPA thermodynamic routine, which can be used in Aspen Plus User Model.
  • ThermoSystem, developed at CERE, contains the CPA parameters of 182 components. User has also flexibility to add additional components and change the binary parameters.

Figure 1. The role of the CAPE-OPEN interface as a standard for interprocess communication.

Figure 1. The role of the CAPE-OPEN interface as a standard for interprocess communication.

Required Software

Aspen Plus to use CPA as a user model, Any process simulator which has CAPE-OPEN platform (e.g. Aspen HYSYS, PRO II) to use CPA and sPC-SAFT.


Alay Arya
DTU Chemical Engineering
+45 45 25 28 64