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Assigning operating pressure for distillation column

Good day Sir/Mam

I am a chemical engineering student from South Africa. I watched the shortcut and rigorous distillation tutorial which were extremely helpful for my project.
However I wanted to ask how do you assign operating pressure for distillation column ? I have to design a pressure swing distillation system, where the first column operates at a low pressure and the second column operates at a higher pressure to separate azeotropic mixture. How can I change the operating pressures of both columns?
Your assistance would be much appreciated.
Thank you in advance


DWSIM 27-07-17, 12:28 a.m. mbali20

Answers:

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Non-ideal mixtures of components forming an azeotrope are very difficult to separate to a purity beyond their azeotropic composition by using ordinary distillation. In such cases, pressure swing distillation (PSD) is a very common practice in chemical industries to separate such mixtures.

The principle behind PSD is to use two columns operated at sequence in two different pressures. So the pre-requisite for the process is that the composition of azeotrope should change significantly with change in pressure. Therefore assigning the opeerating pressure depends on the component system and the pressure at which their azeotropic composition changes significantly.

In DWSIM, the distillation column pressure can be entered under the Column Configuration >> Stages where one can enter the pressure for every stages individually or one can also enter the top & bottom pressure and extrapolate to get the pressure of stages.

20-02-18, 10:42 a.m. Priyam_Nayak


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