清华大学：《化工原理》课程PPT教学课件（下）Distillation：Summary（英文版）

Distillation: Summary Distillation is a widely used separation process The separation is based on the volatility difference of the components to be separated

Distillation : Summary • Distillation is a widely used separation process. • The separation is based on the volatility difference of the components to be separated

Wide application of distillation WHY? Volatility difference exists for most mixtures Only heat is needed for the separation, no other extra agents are needed So the products may be pure

Wide application of distillation: WHY? • Volatility difference exists for most mixtures. • Only heat is needed for the separation, no other extra agents are needed. So the products may be pure

Classification of distillation Relative volatility Process Example big Equilibrium H, and oil distillation or flash distillation medium Benzene fractionation and tolune small azeotropic Absolute distillation and thanol extractive distillation D production

Classification of distillation Relative Volatility Process Example big Equilibrium distillation or flash distillation H2 and oil medium fractionation Benzene and tolune small Azeotropic distillation and extractive distillation Absolute ethanol production 1 2 3 4

Flash distillation dew point line bubble point line XAOI JA

Flash distillation T xAor yA dew point line bubble point line

Fractionation with rectifying section and stripping section column with rectifying section and stripping section condenser(total and partial), accumulator cooler cold water reflux and overhead product reboiler: steam and condensate bottom product

Fractionation with rectifying section and stripping section • column with rectifying section and stripping section • condenser(total and partial), accumulator, cooler: cold water • reflux and overhead product • reboiler: steam and condensate • bottom product

Equipment to implement distillation process Plate tower or column Packed tower or column

Equipment to implement distillation process • Plate tower or column • Packed tower or column

Structure of plate tower sieve plate; perforations downcomer weir

Structure of plate tower • sieve plate; • perforations; • downcomer; • weir

Calculation of distillation process minimum reflux ratio minimum number of trays optimum reflux ratio and number of plates

Calculation of distillation process • minimum reflux ratio • minimum number of trays • optimum reflux ratio and number of plates

McCabe-Thiele method for the calculation of theoretical tray number equilibrium stage assuption (ideal stage) constant molar overflow assumption operating line and equilibrium curve feed line

McCabe-Thiele method for the calculation of theoretical tray number • equilibrium stage assuption (ideal stage) • constant molar overflow assumption • operating line and equilibrium curve • feed line