MASS TRANSFER AND SEPERATION Question Papers (Regular, 2006)

SET: 4

1. (a) Write the Ficks law of diffusion for ‘Z’ direction. What is the significance of diffusion coefficient?

(b) Derive the equation for steady state diffusion of gas (A) through the wall of a hollow cylinder?

2. (a) Distinguish between Eddy and Molecular Diffusion?

(b) Explain Penetration Theory versus Two Film Theory?

3. (a) Write and explain Rayleigh’s equation?

(b) A binary mixture containing 15 mole percent n-Butane and 85% n-Pentane is

Subjected to simple Batch distillation at atmospheric pressure. If 80% of the Butane

is removed by distillation process, how much Pentane would be removed? What

would be the composition of the remaining liquid? Average relative velocity = 3.5

4. A saturated liquid feed of 200 mol/h at the boiling point containing 42mol% heptane and 58% ethyl Benzene is to be fractionated at 101.32 kpa abs to give a distillate containing 97mol% heptane and bottom containing 1.1mol% heptane. The reflux ratio used is 2: 5: 1. Calculate the mol/h distillate mol/h bottom bottoms, theoretical number of trays and the feed tray chamber. Equilibrium data are give at 101.32 kpa abs pressure for the mole fraction n-Heptane HX and HY.

5. (a) What is a plait point?

(b) Draw the flow diagram for diagram for continuous counter current multistage extraction operation.

6. Acetaldehyde(5%) is in solution in toulene and is to be extracted with water in a five stage co-current unit. If 25 kg water is used per 100 kg feed, find the amount of acetaldehyde extracted and the final concentration. If Y = KG Acetaldehyde/kg water and X = kg Acetaldehyde/kg toulene then Ye = 2.20x represents the equilibrium relation

7. (a) Explain in detail break through curve and its significance?

(b) indicate how rate of adsorption in fixed beds is estimated.
8. Discuss in brief about principles of ion exchange.