Sources of thermodynamic data in Aspen-Plus
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I would like to ask that, for example, after we enter the component data and select a thermodynamic model such as the activity coefficient equations NRTL or WILSON, Aspen-Plus provides interaction parameters (which will be blank if they are not available, and need to be entered manually). These parameters come from sources such as Dechema and DIPPR. What can be said about the reliability of these specific data? I mean, the same literature publishes a lot of basic data or parameters for such components – how does Aspen determine which one is more suitable? At the same time, there are two types of fundamental phase equilibrium data: isobaric and isothermal data. How should one choose in such a case? I seek the advice of experts to guide me
Hasn’t anyone replied yet? I’ll take the brunt of it first; don’t let it sink. I hope some expert can help me answer this question. Thanks
It’s difficult; I don’t understand it either. I’ll have to look at what experts do
This is Aspen Company’s matter. They generally conduct an optimal evaluation of various thermodynamic models and select the better ones based on the specific engineering results obtained in the past by using those models. In short, thermodynamic models are also a field in constant development, and not all models provided by Aspen can yield accurate predictions. Of course, different simulation software may use different thermodynamic models, but the differences are generally not significant.
The data from ASPEN is not perfect; for ordinary simulations, you can use ASPEN’s data, but for research and design purposes, it’s better to use your own thermodynamic data.
I fully agree with what was said upstairs. Thank you all for your replies; haha, I get it now :)
This post was last edited by lsrwan on 2009-7-3 at 13:25. Experiments generally involve isothermal or isobaric data; Aspen uses multiple sets of experimental data and relates them to temperature and pressure by adjusting parameters. This approach allows a single set of parameters to be applied over a wide range of temperatures and pressures, rather than just at one specific temperature or pressure point. You can compare its NRTL model with the NRTL model described in textbooks – the textbook version has only two parameters, AIJ and AlphaIJ, while this model has six parameters: AIJ, BIJ, CIJ, DIJ, EIJ, and FIJ. This is why it can be applied over a wider range of conditions; however, it’s still better to use the model that is specifically designed for your needs. I just realized it was a problem from last year, haha.
Personally, I think the data in the Aspen library is generally reliable. The key to performing simulation calculations lies in the selection and verification of property methods. A model can only be used once it has been validated through experiments or other methods. Otherwise, everything calculated will be garbage. Aspen is just a calculation tool, and the accuracy of its results needs to be verified from various aspects.
Recently, while working on some design calculations, I found that two substances should form an azeotrope under actual conditions; however, under the same conditions, no azeotrope is formed in Aspen. I’m not sure why
Regarding thermodynamic data, it is also related to a certain extent to the property calculation methods chosen; the formulas used to determine the thermodynamic parameters vary depending on the different property calculation methods and international standards