B.E-B.E Biotechnology 1st Sem Mass Transfer)(315462(University of Pune, Pune-2013)
[Total No. of Questions:12] [Total No. of Printed Pages: 3]
UNIVERSITY OF PUNE
[4364]-641
T. E. (Biotechnology)(Semester-I) Examination - 2013
(Mass Transfer)(315462)( 2008 Course)
[Time: 3 Hours] [Max. Marks: 100]
Instructions:
1 Answer any three questions from each section.
2 Assume suitable data, if necessary.
3 Figures to the right indicate full marks.
4 Use of programmable calculator is not allowed.
SECTION -I
Q.1 Derive the equations for the following with proper 16
nomenclature and assumptions
i. Steady State molecular diffusion in liquids at
rest.
ii. Steady State equimolal.
OR
Q.2 Discuss in detail Theories of Mass Transfer. 16
Q. 3 A Write short notes on Distillation Column Internals. 8
B 100 moles of Benzene and Toluene containing 50 8
mole% Benzene in the residue is 33% by mole.
Calculate the total moles of the mixture distilled? Take
relative volatility value as 2.4
OR
Q. 4 A Define Fenske's Equation. What are its applications? 8
B Data of mole fraction of carbon disulphide in the liquid 8
and in vapour evolved from the mixture during
distillation of carbon disulphide carbon tetrachloride mixture as follows.
x 0 0.2 0.4 0.6 0.8 1
y 0 0.445 0.65 0.795 0.91 1
Determine graphically number of theoretical plates
required.
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Q. 5 A Derive the operating line equation for Equilibrium 9
distillation and deduce the operating lines for various ranges of feed values.
B Write short notes on the following with suitable 9
examples.
i. Minimum Boiling Azeotrope ii. Total Condenser
OR
Q. 6 What is Reflux ratio? How does it affect the purity of
the product? Write short notes on Minimum and Total
Reflux ratio. Which one works best in order to achieve a
quality product?
SECTION II
Q. 7 Write short notes on Equilibrium solubility of Gases in liquids for the following systems.
i. Two Component systems ii. Multi Component systems
OR
Q. 8 A Write short notes on Reboiled absorbers. How efficiency 8
is increased in these type of absorbers?
B 5000Kg/hr of a So2 air mixture containing 5% by 8
volume So2 is to be scrubbed with 200000 Kg/hr of
water in a packed tower. The exit concentration of So2 is
reduced to 0.15%. The tower operates at 1 atm pressure.
The equilibrium relationship is given by Y=30X. If the
packed height of the tower is 420cm, estimate the height of transfer unit.
Q. 9 1400Kg (bone dry) of granular solid is to be dried under 16
constant drying conditions from a moisture content of
0.2Kg/Kg dry solid to a final moisture content of
0.02Kg/Kg dry solid. The drying surface is given as
0.0615m2 /Kg dry solid. Under the same conditions the
following rates were previously know. Estimate the time required for drying.
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Moisture content 0.3 0.2 0.14 0.096 0.056 0.046 0.026 0.016
Rate of Drying 1.71 1.71 1.71 1.46 1.29 0.88 0.54 0.376
OR
Q. 10 Derive the expression for time of drying for the 16
following conditions.
i. Constant rate period ii. Flling rate period
Q. 11 Give a brief description about the following 18
i. Methods of Super saturation ii. Mier's Super saturation theory
OR
Q. 12 A A hot solution containing 5000kg Na2CO3 and water 9
with a concentration of 25% by weight Na2CO3 is
cooled to 293 K and crystals of Na2CO3.10 H2o are
precipitated. At 293 K the solubility is 21.5kg anhydrous
Na2CO3per 100kg of water. Calculate the yield of
Na2CO3crystals obtained if 5% of the original water in
the system evaporates on cooling.
B Write short notes on solubility curves in Crystallization. 9
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