COSMOthermCO: Process Modelling & Engineering Simulation
with COSMOtherm

COSMOtherm is able to provide valuable thermodynamic data that can be used in a Process Modelling & Engineering (PME) simulation environment. The classical approach of applying thermodynamical data computed by COSMOtherm within PME simulations is to fit the data to an activity coefficient model and feed this to the PME simulation as pseudo-experimental data.
This approach has two flaws:

• First, some amount of COSMOtherm's accuracy is lost if the computed activity coefficients are fitted to an activity coefficient model like UNIQUAC or NRTL.
• Second, the fitting procedure and the feeding of the data into the PME simulator involve some manual work and time effort that the chemical engineer often does not want to invest.

From these considerations COSMOlogic deployed a direct way of incorporating COSMOtherm computed thermodynamic data into PME systems: COSMOthermCO.

COSMOthermCO makes available COSMOtherm calculated properties in Process Modeling & Engineering software applications via CAPE-OPEN standard interface definitions. CAPE-OPEN (Computer-Aided Process Engineering Open Simulation Environment) is as a collaborative project between a group of operating companies, technology vendors and academic groups: Different simulators have different strengths, so that to obtain the best results for a particular problem, access to more than one vendor simulator and to in-house software containing company specific methods or data is usually required. The main objective of CAPE-OPEN is to enable native components of a simulator to be replaced by those from another independent source, or that are part of another simulator, with minimal effort in as seamless a manner as possible. So that it will be possible to assemble a process model from a set of software components encapsulating physical property methods, unit operation models and numerical algorithms. that are communicating through the open standard interfaces. CAPE-OPEN delivered interface standard specifications for the main components of a process simulation. COSMOthermCO is a CAPE-OPEN compliant ICapeThermoPropertyRoutine (i.e. a CAPE-OPEN encapsulated physical property method), which was developed by COSMOlogic in collaboration with AmsterChem (J. van Baten, R. Baur). COSMOthermCO allows the direkt access of COSMOtherm thermodynamic properties within PME simulators without the need of creating or processing any input or output files or converting any specific data formats. For a given temperature and mixture concentration COSMOthermCO provides:

• Activity coefficients of all compounds
• Unconstrained derivatives of the activity coefficient with respect to temperature
• Unconstrained derivatives of the activity coefficient with respect to concentration
• Properties related to the activity coefficient and its derivatives: excess energy, activity, ...

CAPE-OPEN/COCO
Compliant

A restricted demonstration version COSMOthermCOLITE is available within the free COCO (Version 1.06 and later) process simulation program (COCO Download). Some simulation flow sheets (COCO flowsheet.fsd documents) that demonstrate the operation of COSMOthermCOLITE within COCO (Version 1.09 and later) can be found here:

• SmallTest-CT-C21-0107-Lite.fsd: A simple stream that employs COSMOthermCOLITE for the calculation of activity coefficient diagram.
• Flash-meoh-etoh-iproh-CT-C21-0107-Lite.fsd: Three-component flash calculation using COSMOthermCOLITE activity coefficients.
• Azeotropic-Distillation-Acetone-Methanol-C21-0107-Lite.fsd: A complex azeotropic distillation simulation using COSMOthermCOLITE acticvity coefficients and operating them within ChemSep distillation columns. Note that the solution of this flowsheet within COCO may take up to two hours calculation time.

Further applications and detailed examples of COSMOthermCO usage with different PME simulators like Aspen+ are given in the pdf-document COSMOthermCO.pdf.

If you are interested in further details on COSMOthermCO or a COSMOthermCO LITE/Demo version,
please contact us.