Distillation-Akul Jain

Contents: VLE Basic terms Flash Distillation Steam Distillation Batch Distillation Multistage fractionation of binary mixtures McCabe Thiele Method Ponchon Savarit Azeotropic Distillation Extractive Distillation Reactive Distillation Conclusion

Vapour Liquid Equilibrium :

Constant T vapour liquid equilibria

Constant P vapour liquid equilibria

Raoult’s law:

For ideal is = 1.

•(+) ve deviation >1•(-) ve deviation <1•Azeotropes

Basic Terms:

Distillation Column Terms:

Relative volatilityCondenserReboilerDistillateBottomFeedLiquid RefluxRectifying sectionStripping section

Flash Distillation

At steady state :

Enthalpy –concentration and equi. Dia.

Steam Distillation :The property of an immiscible liquid mixture forms the basis of steam

distillation.Case 1 – Substance A is immiscible with water and feed contains A and some traces of non volatile impurities .

If system is not at equilibrium than

E – Vaporizing efficiency

Case 2 – The feed is a mixture of A and C ; C is an essentially non volatile substance, A and C form an ideal solution and are immiscible with water.

;

Batch Distillation :

Continuous Multistage fractionation of binary mixtures :

For 1

For 2

For 3

For 4

McCabe Thiele Method

Rectifying section :

Stripping section :

Feed line :

Total reflux :

No of stages :

Fenske’s equation

Minimum reflux ratio :

Ponchon Savarit :Rectifying section : Stripping section :

Azeotropic distillation :

Azeotropic distillation of acetic acid water with butyl acetate.

Here butyl acetate is entrainer.

Extractive Distillation :

Reactive Distillation

Advantages of RD :1. Single column replaces one reactor and 3 distillation

columns which is process integration.2. Less material is required for the construction of just

single column hence RD is much more cheap. Statistically, RD reduces about 50% of the cost as compared to conventional process.

3. Low energy consumption.4. Lower operating cost .

Disadvantages of RD :5. Degree of freedom is 3 for RD but for conventional

process it is 9. Hence conventional process gives us more variables than RD.

6. Above mentioned volatility problem is also a disadvantage. It limits it to very few reactions.

7. In some processes the optimum conditions of temperature and pressure for distillation may be far from optimal for reaction and vice versa.

Conclusion:

There are many methods to separate various mixtures . Maximizing the product by using minimum amount of investment is our final aim.

Thank you