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[Antonia]

Hallo!

I'm trying to regress DECHEMA DATA in Aspen Plus for the NRTL-model.
Implemented Data sources give wrong activity coefficients at my conditions. VLE works well around 100°C, but my simulation is at low BuOH concentration and room temperature.

When I implement DATA from DECHEMA, ASPEN regresses good NRTL Parameters,( like NRTL/1,NRTL/2,...), but with this regression the VLE is wrong.

If I have a separation step at room temperature and a distillation downstream, is the only possibility for the simulation to have a different model at each unit? (VLE at distillation and regressed model at separation step)
Does anyone know how ASPEN calculates the NRTL model? How can I get a model, with these two combined?

I'm looking forward for your replies.
Thanks for your help.

Antonia

[Antonia]

hallo!

I solved the problem on my own.
To make a model, which works at room temperature and VLE, I used both data sources (infinite activity coefficient Data and VLE Data) for one regression. The weight of the data sources is equal with 1. Comparison with different weights doesn't influence the results.
This model calculates gamma and VLE almost perfectly.

greetings
Antonia