Flash Separations: Summary

Key points from this module:
  1. The exiting liquid and vapor streams are in equilibrium.
  2. The same calculations (mass balances, phase equilibrium) are also used for systems with more than two components. 
  3. An energy balance is also necessary to determine the outlet temperature.
  4. When pressure is lowered on a hot liquid, some of it evaporates.
  5. When this is done adiabatically, the temperature decreases to provide the heat of vaporization.
  6. The operating line relates the compositions of the two exiting streams. 

From studying this module, you should now be able to:
  1. Use mass balances and phase equilibrium equations to determine outlet compositions and flow rates for a flash drum if the outlet temperature is known.
  2. Use mass balances, phase equilibrium equations, and an energy balance to determine outlet compositions and flow rates for an adiabatic flash drum.