I have a question regarding simple distillation, as well as the principles of physical chemistry and chemical engineering
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I didn’t master the skills well when I was studying, and I’m now trying to make up for it; I hope everyone can offer some guidance. 1. For a two-component system consisting of fully miscible light component A and heavy component B that does not form an azeotrope, assuming that the initial amount of light component A is fixed at 100 g, and by varying the amount of heavy component B—such as 20 g, 50 g, 100 g, 200 g, 500 g, etc.—simple distillation under constant pressure is carried out so that the final amount of light component A in the system remains fixed at 5 g. What are then the bubble points required for distilling this series of compositions? 2. If the initial amount of light component A is fixed at 100 g, and the amount of heavy component B is variable, the bubble point is fixed; when the same bubble point is reached, only 5 g of light component A remains. Can this be achieved by changing the initial amount of heavy component B? 3. If I want the final amount of lightweight A to be fixed at 5g, with the initial amounts of components A and B as well as the bubble point being uncertain, how can I make adjustments to achieve this result? 4. If all the parameters mentioned above are fixed, and at a certain bubble point the remaining amount of light A is 5g, then by reducing the pressure, can my requirements be met at an even lower bubble point?
There are too many questions; let’s talk about the first one. With two components and simple distillation, given the initial composition, there is only one solution at certain temperature and pressure conditions. It’s not possible for B to have values of 20, 50, or 100 while only 5 grams of A remain in the end; otherwise, the temperature and pressure would need to be changed, which would result in multiple different processes. For the rest, follow this approach.
Maybe my description isn’t clear enough; what I would like to ask is... The initial amount of the light component A is fixed, for example 100 g, and the bubble point temperature at the end of distillation is also fixed, for example 160°C. Under constant pressure conditions, by changing the initial amount of the heavy component B – with values ranging from 20 g to 200 g – what pattern does the remaining amount of the light component A follow?
This can be calculated; it is covered starting from the chapter on distillation in the principles of chemical engineering. If one only wants to identify the patterns, then consulting phase diagrams (if they are available) will suffice.
Okay, I’ll go and study it again to see if I can understand it. If I’m still confused, I’ll come to you to learn more:handshake