Composition of the condensates from the primary and secondary condensers of the distillation tower
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The vapor phase in the overhead vapor line of the distillation tower contains several components; Material A has a boiling point of 70°C, while Material B has a boiling point of 90°C, and A and B are isomers. Is there any difference in the composition ratio of the condensates from the two condensers? 1: The composition of the two streams of condensate is exactly the same ； 2: The content of Material B in the primary condensed liquid is higher than that in the secondary condensed liquid, while the proportion of Material A is slightly lower. I would like to ask which one is the correct answer in these two cases?
Condensation is a gas-liquid equilibrium process; the components are determined solely by the system’s pressure and temperature, and there is a one-to-one correspondence between them. Given that the system pressure remains stable, then the composition depends solely on temperature; the lower the temperature, the higher the concentration of the lower-component. So, the extent of the difference between the components depends on the condensation temperatures for primary and secondary condensation.
It should be the compounds with higher boiling points that condense first; at least in the condensate from the first condenser, the proportion of compounds with high boiling points should be high. Looking forward to in-depth explanations from experts
Thank you. So, as you said, if the temperatures of the two are different, the composition ratio of the condensate must be different, right?
Of course, the composition will definitely differ at different temperatures, provided that the pressure is the same in both cases