Distillation

Distillation Alcohol-water solution is fed into a distilling still at the rate of 1000 kg per hour. The solution analyzes 30% ethyl alcohol by weight, the distillate contains 90% eth and the bottom 8% ethyl alcohol, calculate (a) kg of distillate per hour (b)kg botto D

OMB: 1000 = D + B 0.9 ethanol

Ethyl Alcohol Balance: F(0.30) = 0.9D + 0.08 B = 1000 - D D= B=

Feed: 1000 ethanol: 0.3

B 0.08 ethanol

e rate of 1000 kg per hour. e distillate contains 90% ethyl alcohol stillate per hour (b)kg bottom per hour (c) % recovery of alcohol. OMB: 1000 = D + B Ethyl Alcohol Balance: F(0.30) = 0.9D + 0.08 B B = 1000 - D 268.29 731.71

Distillation A distilling column is fed with a solution containing 0.45 mass fractions of benzene and 0.55 mass fr If 95% of benzene must appear in the overhead product, while 92% of toluene appears in the residue D

OMB: 100 = D + B 0.95 benzene 0.05 Toluene

Feed 100 0.45 C6H6 0.55 C5H6

Benzene Balance: Benzene in D=42.75 Benzene in B=2.25 Toluene Balance Toluene in B =50.6 Toluene in D= 4.4

B 0.92 toluene 0.08 Benzene

% Composition in the Distillate: benzene = ### toluene =9.33

benzene and 0.55 mass fraction toluene. ene appears in the residue, calculate the composition of distillate and bottoms.

in the Bottom: benzene =4.26 toluene =###

Distillation Dilute alcohol from fermenting vats contains 11.15% ethanol. The distillate contains 95% alcohol while the bottom contains 0.5% alcohol. As distillation proceeds, a side s The total recovery of alcohol in the distillate and in the side stream is 96.5%. On the basis of 1000 kg calculate the amounts of the bottom, distillate and the side stream. 100- 96.5 3.5= D 0.95

FEED 1000 0.11 alcohol

S

B

0.4

0.01

OMB: 1000= D + S + B Alcohol balance: 0.005 B = 0.035(1000)(.1115 B= 780.5 D +S = 219.5 D=219.5-S D= 36 S= 183.5

ate contains 95% ation proceeds, a side stream containing 40% alcohol is removed. .5%. On the basis of 1000 kg of feed,

000= D + S + B

B = 0.035(1000)(.1115)

A mixture of 2 mol% ethanol and Steam, admitted through an ope than 0.01 mol% ethanol. The fee For ethanol-water solutions, the

Overall Ethanol Balance: V(ya-yb) = L(Xa-Xb) 0.2(ya-0) = 1(0.02-0.00 ya=

ya - y*a = yb - y*b = y*b - y*a = yb - ya =

mol% ethanol and 98 mol% water is to be stripped in a plate column to a bottom produ ed through an open coil in the liquid on the bottom plate, is to be used as a source of v % ethanol. The feed is at its boiling point. The steam flow is to be 0.2 mole per mole of ater solutions, the equilibrium line is given by ye = 9.0xe. How many ideal plates are ne F = L =1

V = 0.2

xa = 0.02

ya= 0

yb = 0

xb = 0 y*a = 9* 0.0020.18 =

y*b = 9*0.0001 0=

V=1 ya = 0.0001

F=1 xa = 0.02

L=1 xb = 0.0001

erall Ethanol Balance: V(ya-yb) = L(Xa-Xb) 0.2(ya-0) = 1(0.02-0.0001) 0.1

V = 0.2 yb = 0

-0.08 0 -0.18 -0.1

N= 7.64

mn to a bottom product containing not more used as a source of vapor. 0.2 mole per mole of feed. ny ideal plates are needed?