Dew-Point, Bubble-Point, And Flash Calculations
J. David Raal, Andreas L. Mühlbauer · 2023
Bubble-point and dew-point calculations find their greatest application in multicomponent distillation, since for a known or specified liquid composition it is usually necessary to find the vapor composition and equilibrium temperature on each plate of the distillation column. In addition to dew-point and bubble-point calculations, adiabatic or isothermal flash calculations may be required for process unit design. Flash calculations differ from all the calculations in that a material balance for the liquid and vapor streams is involved. The amount of the feed evaporated (if liquid) or condensed (if the feed is vapor, as in a partial condenser) depends on the feed temperature and pressure and the amount of heat added or removed in the vaporizer. The determination of all the unknown variables is appreciably more difficult than for the isothermal flash, since the flash temperature is now unknown and must be found by an enthalpy balance.