In the expression for the chemical potential of an ideal solution is given by the next equation, a modification may be necessary to describe nonideal solutions, or real solutions. The modified expression is:
where γi is called the activity coefficient which is generally a function of temperature, T, composition, x, and pressure, P. The magnitude of γi depends on the magnitude of μi0 (T, P), which is also unknown.
Usually, the calculation for such coefficients is extremely difficult as there are so many considerations needed for it. However, there are several mathematical models that can help us compute for these values. Each of them is specific for some conditions so you may need to analyse what type of system behaviour you are trying to predict. Next, we will share a table with you in which you can find the most common models used, the type of systems where you can use them as well as the limitations for each of it. |
Next, we will share a table with you in which you can find the parameters and equations used for the different activity coeffcient models.
The next file is a brochure about the NRTL model. It gives more specific information about this activity coefficient model.
![](http://www.weebly.com/weebly/images/file_icons/pdf.png)
ntrl.pdf |
References
Firoozabadi, A. (2016). Thermodynamics and Applications in Hydrocarbon Energy Production. New York: McGraw-Hill Education.
Firoozabadi, A. (2016). Thermodynamics and Applications in Hydrocarbon Energy Production. New York: McGraw-Hill Education.