Is the number of stage constant? When the components in the system change?

[Theophile]

Hi everyone,

If I find the number of stage for the test run for Benzene Toluene unit
and I find that the number of equilibrium stage should be 50 stages.

If I turn the system into the extractive distillation.
To separate Benzene and other non-aromatic components by using the solvent, NFM.

Shall the number of stage in this case be 50?

Thank you for your answer.

 

[georgeverghese]

If NFM enables better selectivity for benzene, then obviously you'll need much less than 50 theoretical trays, assuming you'got a decent extraction solvent flowrate, and residual benzene in lean feed extraction solvent is low.