MASS TRANFER AND FLUID PARTICLE MECHANICS

LAB

REPORT

ON

VAPOR LIQUID EQUILIBRIA

Submitted by:

Group 1, SubGroup 5

Sarneet Kaur Broca(2009ch10099)

Aakash Sharma(2009ch10051)

Manu Garg (2009ch10078)

VAPOR LIQUID EQUILIBRIA

Aim:

To determine the vapor-liquid equilibrium curve for the CCl4, Toluene mixture and compare it with the VLE data (either calculated or obtained from literature)

Theory:

Vapor liquid diagram shows relation between the composition of the vapor and that of the liquid in equilibrium with vapor, for a binary mixture at constant pressure or constant temperature. If the liquid and vapor behaves ideally, such curves are calculated as follows,

According to Raoult’s Law:

P1 = p1x1

P2 = p2x2 (1)

Where,

P1 and P2 are partial pressures of component

x1 and x2 are mole fraction in liquid

According to Dalton’s law of partial pressures

P1 = Py1 P2 = Py2 (2)

Where,

y1 and y2 are mole fraction in vapor

p1 and p2 are vapor pressure of pure components at the same temperature as mixture

P is the total pressure

Equating (1) and (2) we get

21

1 2

P px

p p

1 1

1

p xy

P (3)

The vapor liquid equilibrium is then calculated by choosing various boiling points of the mixture and x and y is calculated. Experimental Setup:

The apparatus consists of round bottom flask with three way open at the top and opened at the bottom

A heating mantle of 1 liter capacity is provided to heat the reboiler A vapor rising and reflux and reflux tube with condensate and sampling is

connected to the reboiler A spiral glass tube condenser is provided to condense the vapor A over head tank is provided to circulate condenser cooling water Two thermometers are provided to measure the liquid and vapor temperature

respectively Calculations: Vt = Volume of Toluene taken (ml) Vc = Volume of CCl4 taken (ml) とt = Density of Toluene (g/cc) = 0.864 とc = Density of CCl4 (g/cc) = 1.59 mt = Mass of Toluene (g) mc = Mass of CCl4 (g) Mt = Molecular weight of Toluene = 92.3 Mc = Molecular weight of CCl4 = 153.8 (a) mt = とtVt mc = とcVc From this equations we can determine (b) Mole fraction of CCl4

c

cc

c t

c t

mM

xm mM M

Therefore, mole fraction of Toluene = xt = 1-xc

Vapor Liquid Equilibrium Observation Sheet Table No: 01. Calibration Chart. S.No Volume of Toluene

(ml) Volume of CCl4 (ml) Refractive Index

1 20 0 1.49

2 18 2 1.486

3 16 4 1.48

4 14 6 1.477

5 12 8 1.474

6 10 10 1.47

7 8 12 1.469

8 6 14 1.464

9 4 16 1.46

10 2 18 1.456

11 0 20 1.45

Refractive Index of Tap Water: 1.334 NOTE: Experiment could not be completed due to faulty apparatus. We tried to take readings but finally even the TA told us that correct reading cannot be taken.

Results and Discussion –

From the experiment and theory: 1. The equilibrium temperature increases as the mole fraction of toluene is

increased in the mixture taken. 2. As seen from the theory, temperature comes out to be slightly less than the

experimental value for both set of readings. This may be due to heat loss to surroundings due to improper insulation. Also some liquid may have entered the heater that might have affected the sensitivity of heater.

Suggestion to Improve the Experiment:

1. The bulb used in the lamp should be of optimum watts as the film of liquid laid down on the prism may have broken due to the heat of the light.

2. An optimum amount of time should be specified in the manual regarding the time given for the mixture made to get mixed uniformly so as to remove partial mixing related errors.