Regarding the reflux ratio in distillation?
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When the overhead material from the distillation column is not removed and full reflux operation is employed, is the feed composition in the column the same as that of the liquid at the bottom of the column? Is it possible to operate with full reflux at the top of the tower, with no product taken out, while product is taken out from the bottom of the tower?
To determine the composition of the material inside the tower, one needs to consider the temperature at various points throughout the tower; by doing so, it becomes clear whether there are any differences. What’s the use of a distillation tower if the top product can’t be extracted? If the light components can’t be obtained, guess where they go?
According to the principles of distillation, under full reflux operation, the components separated by the distillation column are the purest, as the minimum number of distillation plates is required in this mode, resulting in the highest separation accuracy. The composition of the material at the bottom of the column differs from that of the feed; at this point, the liquid level in the reboiler at the top of the column continues to rise until it overflows, and further progression will disrupt the equilibrium of the entire column. As for the second issue mentioned, it’s fine for a short period of time, but it cannot be maintained for a long time.
Full reflux, with no liquid phase used; the gas phase will be recovered!
In a full reflux column, there is no liquid or gas withdrawal from the middle section of the tower; according to material balance, can the bottom of the tower and the feed be different?
This can be done as a temporary measure at the beginning of operation; when there is full reflux at the top, the composition of the material in the reactor bottom and at the top of the tower is not exactly the same, and this depends on the composition of the feed. If the material with a purity of 99% is completely recycled, the difference between the components at the top and bottom of the tower is very small. Whether it is extraction from the top of the tower or from the bottom, operation is feasible in a short period of time.
The answer to the first question is that \"whether feeding is continuous or not makes a difference; the concentration of the Reorganization components at the bottom of the tower is slightly higher than that in the feed\"”； The second question is: \"If feeding and extracting continuously, the components of the final feed and extract are almost identical.\" If no feed is supplied and only extraction is carried out, the composition of the extracted material will have a slightly higher proportion of heavy components, and eventually no more extraction will be possible. I don’t know if you’re seeking help or testing me. If it’s for seeking help, it’s better to take some time to read the chapter on distillation principles.
The composition of the feed and the liquid phase inside the tower differs; the feed contains light components. Full reflux for a short time is okay, but the material at the top of the tower still needs to be removed.