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saft gamma mie parameters

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saftgm

Student
Oct 20, 2021
1
Hi,

I'm new to the forum and I have a few questions.

I am trying to understand SAFT-gamma-Mie methodology based on the following papers:
1. T. Lafitte et al. "Accurate statistical associating fluid theory for chain molecules formed from Mie segments"
2. V. Papaioannou et al. "Group contribution methodology based on the statistical associating fluid theory for theteronuclear molecules formed from Mie segments"

I am confused in the usage of terms 'segment', 'group' and 'components'.

Taking ethanol as an example,
In ideal term for Helmholtz energy, is it considered as free energy due to non-interacting, ideal segments of the molecule (ie, is it the free energy of ideal CH3, CH2 and OH spherical segments?) or non-interacting, ideal molecules (non-interacting CH3CH2OH)?

So, in the ideal term, is the mole fraction that for of ethanol in a mixture of molecules of ethanol (That is 1 right😵?) or is it sum of mole fractions of CH3 , CH2 and OH groups in ethanol?
Similarly, is the volume considered the volume of CH3CH2OH molecule or that for the whole system of ethanol (is it taken as 1 mole)?

There are NC and NG terms in AHS in the monomer free energy contribution.


Any help is greatly appreciated.

Thank you
 
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