100 kmoles/h of saturated liquid containing 10 mole % pentane, 55 mole % hexane, and 35 mole % heptane was separated using multistage distillation column at 380 mmHg. The top and bottom temperature of the column is 51.3°C and 76°C respectively. It is desired to have 99.5 % recovery of the hexane in the distillate. The mole fraction of the hexane in the distillate should be 0.75. The reflux ratio used was 1.2 the minimum. The θ value for Underwood’s correlation is 1.29. Using shortcut method, calculate the number of tray required and the feed tray location for this distillation. Antoine coefficient for the components was given in Table 1.

 

Table 1: Antoine equation coefficient

Component

A

B

C

Pentane

6.87632

1075.78

233.205

Hexane

6.87024

1168.72

224.21

Heptane

6.89385

1264.37

216.636

mixture of 45 mole% n-hexane and 55 mole

% n-heptane is subjected to continuous

fraction in a tray column at 1 atm total

pressure. The distillate contains 95% n-hexane

and the residue contains 5% n-hexane. The

feed is saturated liquid. A reflux ratio of 2.5 is

used. The relative volatility of n-hexane in

mixture is 2.36. Determine the number of ideal

trays required.

We ar e separating a mi xture of 40 mol% iso-pentane, 30% n-hexane, and 30% n-h eptane

fed into the distil la tion col umn at the fe ed ra te of 1,000kmol/h. We desire a 98 m ol%

recove ry of n-he xane in the bottom prod uct and a 99% recoveryof iso-pentane in the

distillate. The feed is a two-phase mixtur e with 40% vapour,and the reflux ratio

L/D=2.5

6.1) Find D and B

6.2) Find co mpositions of distillate and bottom products

6.3) Calculate the values of L , V , L , and V , assuming thatCMO is valid

D is Distillation and B is bottoms.