Distillation McCabe - Thiele

[peruanolimense]

Hi, my name is Carlos Reynoso, and I'm a student from Perú.
I have a question about distillation using McCabbe-Thiele method... The distillation column is like this:

As we can see in the image, we have a normal column, except that there is a feed (B ) on to the partial condenser. That makes things a bit difficult...
The question is about the net flows:
[ul]
[li]Undoubtedly, there is a net flow in the Stripping section (where the boiler is, the lower part of the column). The net flow in that section would be:
[/li]
[/ul]

So the net flow in the Stripping section is:

Δ[sub]R[/sub]=L[sub]m[/sub]-V[sub]m[/sub]=R​

z[sub]ΔR[/sub]·Δ[sub]R[/sub]= L[sub]m[/sub]·x[sub]m[/sub]- V[sub]m[/sub]·y[sub]m[/sub]​

This is correct 100% sure, but the problem is with other net flows. I do not know if there are more net flows. In a normal, usual column, we have the net flow in the stripping section (the one we have in the upper image), and the net flow in the rectifying section. However, as we have a feed (B ) in the partial condenser, I do not know if we have a net flow in the rectifying section. Does anyone know if we have a net flow in the rectyfying section? (as we have feed in the partial condenser).



Some people say there is only the net flow in the stripping section, and no net flow in other sections of the column. Other people think that we have the net flow in both the stripping section and the rectifying section, and finally, other people think we have the net flow in the stripping section and between the feed to the column (A) and the feed to the partial condenser (B ).



As for now, I only need to know the question to the following answer:

Do we have more net flows in the distillation column of the above image? (100% sure there is a net flow in the stripping section)



Thanks, please sorry for my low english-level, and again, thankyou very much!

Have a nice day.

 

[peruanolimense]

Someone?

 

[3DDave]

It is Christmas Day, a generally North American participation, and not an on-call service.

So, Happy Holidays (and I hope a nice start to Summer). It might be a day or few before the chemical engineers return, ready and able, from metabolizing ethanol and sugar.

 

[dik]

Why would you drink sugar?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[3DDave]

You wouldn't drink it - but I was hoping that before too much ethanol was imbibed the plastic wrappers were removed from the candies in order to avoid the colorful, but painful, surprise the next day.

 

[dik]

Hehehehehe

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[peruanolimense]

Now that chemical engineers have metabolized ethanol and sugar, can someone help me?

Happy Holidays for you all![santa2]

 

[jari001]

What control volume are you considering for the rectifying section?

I'm also confused by the term "net flow" - you showed what the steady state mass balance is for the rectifying section, which means there is no change/no net flow with respect to time for the control volume you highlighted.