Specific distillation assumptions
Material transfer - Ideal compartmentalized distillation

We assume that distillation operations are adiabatic, except at the ends of the column. In addition to being consistent with reality, this assumption allows us to use simple barycentric relationships on the enthalpy diagram.

Calculations are based on the assumption that the device operates at constant pressure. Obviously, pressures vary in a device due to pressure losses associated with flow; these pressure losses are only significant for operations conducted at pressures well below atmospheric pressure.