On the regression of UNIFAC group parameters
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I have not used Aspen before, so I would like to ask the experts here: The ternary vapor-liquid equilibrium data for certain T and P values have been determined experimentally. However, there is one new group that needs to be defined. Now it is necessary to fit the interaction parameters (UNIFAC) between this new group and the other groups. The Q and R values for this new group have already been calculated using the BONDI method. So, can these values be used with Aspen? What is the specific method?
I also checked the user manual, but it seemed a bit confusing. The new group that needs to be defined is -O-N=O, which belongs to the nitrite class; it cannot be broken down further and must be used as a whole
Sure. The group binary interaction parameter can only be obtained through a data regression step, whereas NRTL/WILSON/UNIQUAC can also be determined using property estimation methods. Since you already have the experimental data as well as the values of q and r, it is possible to calculate the interaction parameter. A+ can be used to define new UNIFAC functional groups, and software can be employed to estimate the values of q and r. Then, based on the post below, perform data regression to determine the interaction parameters. http://bbs.hcbbs.com/thread-593697-1-1.html