Read the summary and the most important questions on Industrial Separation Processes | 9783110306699

• 2 Evaporation and distillation

• 2.1.1 Introduction

• When is separation by evaporation possible?

  When there is a differece in volatility between compounds.

• What is the basis of planning an evaporation separation step?

  The thermodynamics of the vapor-liquid equilibrium need to be known.

• 2.1.2 Vapor-liquid equilibria

  This is a preview. There are 10 more flashcards available for chapter 2.1.2
  Show more cards here

• What is the vapor-liquid equilibrium and how can it be depicted?

  The vapor-liquid equilibrium (VLE) is the composition of the phases at thermodynamic equilibrium.

• What is the distribution coëfficient Ki?

  The distribution coëfficient is a constant that relates the concentration of component i in liquid with the concentration of i in vapor.
  K_i is a function of temperature and pressure. It does not change with changing concentrations.

• How is the selectivity or relative volatility defined?

  the higher this number the more efficient separation by distillation will be.

• What is Dalton's law?

  Dalton's law relates the partial pressure of i to the concentration of i in vapor.
    This is for ideal gases.

• Why is the relative volatility less sensitive to temperature than the equilibrium ratio?

  The relative volatility is dependent on the vapor pressure.

• Does the relative volatility increase or decrease with increasing temperature?

  In general the vapor pressure of the more volatile compound increases at a slower rate with increasing temperature than the less volatile compound. Therefor the relative volatility generally decreases with increasing temperature.

• What is a minimum boiling azeotrope?

  A minimum boiling azeotrope boils at lower temperatures than each of the compounds in their pure state.

• What is a maximum boiling azeotrope?

  A maximum boiling azeotrope boils at higher temperature than each of the compounds in their pure form.