I would like to ask about the setting of the top pressure in a distillation tower
Thread Content
For the pressure at the top of the distillation tower (that is, in the condenser), should it be set based on the bubble point pressure or the dew point pressure? I’ve seen many examples in which, in the case of a full condenser, the bubble point pressure is calculated based on the estimated outlet temperature of the condensate water, and this value is then used as the top pressure of the tower. But why not set it at the pressure corresponding to the dew point before condensation? What about a fractional condenser? I’m not sure what the basis is; could someone please give some guidance?
1. If set at the pressure corresponding to the dew point before condensation, only the heaviest components in a multi-component product will condense. 2. Separators are typically used to remove non-condensables, and they are set at the dew point of the lightest component required
I agree with what was said on the 2nd floor, but I would like to add that the question posed by the original poster seems to be a bit unclear. The top pressure is not determined solely based on the condensation temperature; it also takes into account the properties of the material (such as whether it tends to polymerize or coking), whether heat integration is required in the entire process, as well as the temperature grade and cost of the coolant.
Thank you to both seniors; really appreciate it!