Regarding the issue of distillation column reflux
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With unchanged operating conditions, does increasing the reflux flow rate raise or lower the column pressure?
Increasing the reflux rate leads to an increase in the liquid flow rate inside the tower; since all other conditions remain unchanged, that is, the heating amount at the bottom of the tower stays the same and there is also no significant change in the gas flow rate inside the tower. If it is saturated liquid-phase reflux, since the gas flow rate remains unchanged and thus the pumping volume also stays the same, the pressure inside the tower does not change, whether operating under vacuum, at atmospheric pressure, or under pressure. If there is a backflow of the supercooled liquid phase, it will cause a decrease in the gas flow rate upon entering the tower; if the pumping volume remains unchanged, the pressure in the vacuum tower will drop, while the pressures in both the atmospheric-pressure tower and the pressurized tower remain unchanged.
If, while keeping the heat input to the tower constant, you increase the reflux on one side alone, the thermal balance of the tower will be disrupted, and you won’t be able to operate this tower