Distillation Example 4 and 5

Example 4

A contnuous fractonatng column is required o separae a mixure of waer and ehanol conaining 0.35 ehanol o give a produc conaining conaining 0.80 mole fracton ehanol and a wase of 0.02 mole fracton ehanol. I is proposed o wihdraw 25 of he feed sream as a side sream wih a mole fracton of 0.5 mole fracton ehanol. If he feed is a liquid a is !oiling poin and a re"ux rato of 2 is used. Determine:  

x *

#um!er of heoretcal plaes required $ositon of he plae from which he side sream should !e wihdrawn 0.0 0.0

0 .% 0.22

0.2 0.38

0 .3 0.5%

%& sages+ ,ide sream - 2nd sage

0.& 0.'3

0 .5 0.(0

0.' 0.(8

0.( 0.85

0.8 0.)%

0.) 0.)'

% .0 % .0

xample 5 A mixure of waer and mehanol conaining 0.%' mole fracton mehanol is contnuousl* distlled in a plae column o give a produc conaining 0.(( mole fracton and a wase of 0.02 mole fracton mehanol. I is proposed o wihdraw 8 /molh as a side sream wih a mol fracton of 0.5 mehanol. A re"ux rato of 2 is applied. 1eermine  

4heoretcal num!er of plaes if feed is %00 /molh ocaton of feed and side sream

x

0

0.%

0.2

0.3

0.&

0.5

0.'

0.(

0.8

0.)

%

*

0

0.&8

0.5)

0.'&

0.')

0.(&

0.(8

0.8%

0.8'

0.)2

%