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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
ME SEMESTER-II EXAMINATION SUMMER 2017
Subject Code: 2723001 Date:29/05/2017
Subject Name: Advanced Mass Transfer
Time: 02:30 PM to 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1

Explain stepwise procedure for multicomponent batch distillation with constant overhead composition.
07

Discuss the advantages and disadvantages of vacuum distillation in detail.
07
Q.2

State and discuss various types of membrane modules in detail.
07

Describe the Phenomena of Reverse Osmosis with neat sketch.
07
OR

Explain concept and working principle of Ultrafiltration in detail with neat diagram.
07
Q.3

Define: Light key component ii) Heavy key component iii) Adjacent key iv) Split key Distributed component vi) Non distributed component
vii) Relative volatility
07

State the concept of super-heated drying and discuss its working principle.
07
OR
Q.3

Find the mole fraction of n-butane in distillate and also in residue by Thiele Geddes method based on following data:
Feed Composition
Component
mole%
n-butane
37
i-pentane
32
n-pentane
21
n-hexane
10
butane is light key component and pentane is heavy key component, feed flow rate F 4750 mol/h, feed is saturated liquid at its bubble point, reflux ratio R distillate flow rate D 1250 mol/ residue flowrate W 3500 mol/h, operating pressure 2 atm(ab.). Assume constant molar overflow and total condenser is used. Equilibrium constant values of n-butane are as follows:
Tray Number
Temperature
KC4
1
22
1.086
2
24
1.156
3
28
1.308
4 (Feed)
32
1.474
5
41
1.904
Reboiler
48
2.300
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Q.4

Explain Fick's law of diffusion through solids.
07

Differentiate between super-heated steam drying and conventional hot air drying.
07
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OR
Q.4 Derive the rate equation for straight mass transfer (Physical Absorption of
based on two film theory with neat sketch.
07
The irreversible reaction
first order reaction with respect to A
takes place on flat solid surface as shown in Figure. Develop the overall rate
expression for this gas-solid reaction where dilute A diffuses through a stagnant
gas film on to a plain solid surface B. On the surface, A reacts with B to give
gaseous which diffuses back into main gas stream.
07
Q .5 Disc uss the criteria for selection of Spray tower, Venturi scrubber and Tray
tower as absorbers.
07
Discuss the Process design steps of Falling film absorber. 07
OR
Q.5 Explain with neat sketch and suitable example the degree of freedom and
variable specifications for typical design cases based on key components and
the required equilibrium stages.
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