VAPOUR-LIQUID SEPARATION PROCESSES

(DISTILLATION OPERATION)

Binary Distillation (McCabe-Thiele Method)

Binary distillation – Separation of TWO components in a liquid solution

Typical example of binary distillation:- (i) Separation of benzene-toluene mixture (ii) Separation of acetone-ethanol mixture (iii) Separation of heptane-ethyl benzene mixture (i) Separation of methanol-water mixture (ii) Separation of ammonia-water mixture (iii) Separation of ethyl benzene-styrene mixture

Equilibrium diagram for system benzene (A) – toluene (B) at 101.32 kPa

Material Balances around Enriching Section

Feed Line Equation Most column operate with the feed as liquid at or near boiling point. The feed is often preheated by heat exchange with the bottoms product or other hot liquids, or by the use of steam.

To keep the number of trays to a minimum, the shift from the enriching to the stripping operating line should be made at the first opportunity after passing the operating-line intersection.

Example

Underwood equation is a shortcut methods for estimation of number of theoretical stages

Rm = 1.17

(b) Theoretical steps = 5.8 (or 4.8 plus a reboiler)