One of the most common issues when using Aspen Plus for liquid-liquid extraction is incorrect data input. It is important to make sure that all relevant data has been imported properly from the database before running the simulation. Additionally, it is important to check that all parameters have been set correctly in the Properties view.

Another issue that can cause problems with liquid-liquid extraction simulations in Aspen Plus is incorrect assumptions about equilibrium and mass transfer coefficients. It is important to make sure that these assumptions are correct and up-to-date before running a simulation. Additionally, it may be necessary to adjust the number of stages or contactors used in order to achieve better results.

Finally, if none of these solutions work, it may be necessary to try a different type of solvent or use an alternative method such as distillation instead of extraction.

In conclusion, if Aspen Plus - Liquid-Liquid Extractor simulations are not converging as needed, there are several changes that can be made in order to improve the results. These include checking data input and parameters, adjusting assumptions about equilibrium and mass transfer coefficients, and trying alternative methods or solvents if necessary.

Sources:

• https://onlinelibrary.wiley.com/doi/10.1002/9781119293644.ch5
• https://lms.nchu.edu.tw/sysdata/doc/e/e622a11263dc8679/pdf.pdf
• https://link.springer.com/article/10