1. Liquid-Liquid Equilibria in Aspen Plus® v8.8
CHEN 354
Texas A&M University

2. N-Methylformamide(1) + Hexadecane (2)
Environmental regulations that aim to improve air quality require reducing sulfur from diesel vehicle emissions
Hydrodesulfurization (HDS) is a typical process in industry that removes sulfur by converting sulfur compounds to hydrogen sulfide
Heterocyclic nitrogen compounds act as inhibitors of HDS
N-methylformamide (NMF) can be used as a solvent for extracting nitrogen compounds from diesel oil
A mixture containing NMF – diesel (represented here as hexadecane) may split into two liquid phases and the NMF-rich phase will dissolve the undesired compounds

3. Hexadecane- rich phase x1
p = 1 atm
T/K
NMF- rich phase x1
Hexadecane- rich phase x1
293.15
0.9993
0.0009
298.15
0.999
0.0011
303.15
0.9984
0.0021
308.15
0.9985
0.0026
313.15
0.9988
0.0027
318.15
0.9987
0.0029
Find binary parameters for the LLE of NMF – hexadecane using UNIQUAC and NRTL
*Source: Hwang, In-Chan, et al. "Binary Liquid− Liquid Equilibrium (LLE) for N-Methylformamide (NMF)+ Hexadecane between ( and ) K and Ternary LLE for Systems of NMF+ Heterocyclic Nitrogen Compounds+ Hexadecane at K." Journal of Chemical & Engineering Data 54.1 (2008):

4. Open Aspen Plus® and add the components N- methylformamide (1) – hexadecane (2)

5. Select UNIQUAC as the method to model the system

6. Input the data (Txx) provided in the table as shown below

7. Click on regression, create a new regression and select UNIQUAC as method. Since a range of temperatures are involved, two interaction parameters for each binary pair (ij and ji) will be used. Click the run button and click OK

8. The two sets of binary parameters are estimated by the UNIFAC method
The two sets of binary parameters are estimated by the UNIFAC method. Similarly, it was also calculated using NRTL.
UNIQUAC
NRTL
What can be concluded about the parameters calculated by the two different methods?

9. Click plots > Txx UNIQUAC NRTL
What can be concluded about the diagrams calculated by the two different methods?

10. Click on Analysis> Binary to study the VLLE of this mixture
Click on Analysis> Binary to study the VLLE of this mixture. Scroll down and click run analysis

11. VLLE diagrams
UNIQUAC
NRTL