TL;DR

Continuous boiloff operation in WFE.

Feed Details :
Component X : 80% ( Boiling point : 105 deg.C)
Component Y : 20% ( Boiling point : 256 deg.C)
Feed Rate : 600 kg/hr
Heating medium : Steam @ 145 deg.C
operating condition : 50 Torr, 90 deg.C ( Based on Aspen Flash Simulation).

Desired Outcome :
TO remove 99% of component X from Component Y.

History :
Earlier this operation was performed in batch mode. Where all of component X was boiled off.
During this, Bottom mass temperature was observed to go upto 120 deg.C uder 50 torr of vacuum.
No component Y was observed in the top distillate - throughout the operation.

Current Scenario :
Observations in WFE :

1. In top distillate component Y is found ~10%.
2. In bottom residue component Y is found ~80%.
3. At 50 torr vacuum, operating temperature is only 40 deg.C.
4. Upon increasing flowrate, component Y is found less in top distillate.

What should be done to minimize loss of component Y in top distillate ?

Chestermiller said:

Have you tried to model this operation? Is the solution ideal so that Raoult's Law can be applied.

The solution is not ideal, but I have modeled the operation in Aspen plus and component Y in top distillate is ~0.5% w/w.

My friend

Aspen Plus has a set of properties packages that will approach the simulation to the real process. It has a tutorial to select the best ones. However, you have to select PR if your components do not have a polar behavior.

To optimize the process, it could be done with the process data. Of course, anyone needs to know X and Y, to have a view of the distillation equilibrium of the mix. Simulation is a tool, just that; but trained process engineers should do it by analyzing the field process data.

Horacio