Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Summer 5th Sem New 2150501 Mass Transfer Operation I Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? SUMMER 2019
Subject Code: 2150501 Date: 06/06/2019
Subject Name: Mass Transfer Operation - I
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.
MARKS
Q.1 (a) Define Diffusivity and state its assumptions for penetration. 03
(b) State and Explain Fick?s law of diffusion? 04
(c) Ammonia gas (A) diffuses through nitrogen gas (B) under steady state
conditions with nitrogen non-diffusing. The partial pressure of A at location is
1.5 x 10
4
Pa and that at location 2 is 5 x 10
3
Pa. the location 1 and 2 are 15 cm
apart. The total pressure is 1.103 x 10
5
Pa and temperature is 298 K. calculate
the flux of diffusion of ammonia. Also calculate flux of diffusion for equimolar
counter diffusion assuming that nitrogen is also diffusing. Take diffusivity at
prevailing conditions are 2.30 x 10
-5
m
2
/s.
07
Q.2 (a) Define N and J type flux. What is the difference between N and J? 03
(b) For equimolar counter diffusion show that D AB = DBA 04
(c) Explain the film theory for mass transfer co-efficient. 07
OR
(c) Explain molecular diffusion in gases in detail. Also discuss steady state
diffusion of A through non diffusing B.
07
Q.3 (a) State characteristics of various types of packing. 03
(b) Describe the working of wetted wall tower. 04
(c) A packed tower is designed to recover 98% CO2 from a gas mixture containing
10% CO2 and 90% by volume air using water. The equilibrium relation used is
y? = 14x?, where, y?= kg CO2/kg dry air and x? = kg CO2/kg water. The water
to gas rate is kept 30% more than minimum value. Calculate actual mole ratio
of water to solute free gas.
07
OR
Q.3 (a) What is minimum liquid ? gas ratio in case of gas absorption? 03
(b) State selection criteria for solvent in extraction. 04
(c) Define F-type and k-type mass transfer coefficients. Also derive the
relationship for steady state equimolar counter diffusion between F and k type
coefficients.
07
Q.4 (a) Write short note on Absorption factor. 03
(b) Define: (i) Weeping (ii) Dumping (iii) Flooding (iv) Tray efficiency 04
(c) 150 kg of nicotine-water solution containing 1% nicotine is to be extracted
with 250 kg of kerosene at 20?C. Water and kerosene are essentially
immiscible in each other. Determine the % extraction of nicotine after single
stage. The equilibrium relationship is Y* = 0.798X, where X and Y* are
expressed as kg nicotine/kg kerosene and kg nicotine/kg water respectively.
07
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Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? SUMMER 2019
Subject Code: 2150501 Date: 06/06/2019
Subject Name: Mass Transfer Operation - I
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.
MARKS
Q.1 (a) Define Diffusivity and state its assumptions for penetration. 03
(b) State and Explain Fick?s law of diffusion? 04
(c) Ammonia gas (A) diffuses through nitrogen gas (B) under steady state
conditions with nitrogen non-diffusing. The partial pressure of A at location is
1.5 x 10
4
Pa and that at location 2 is 5 x 10
3
Pa. the location 1 and 2 are 15 cm
apart. The total pressure is 1.103 x 10
5
Pa and temperature is 298 K. calculate
the flux of diffusion of ammonia. Also calculate flux of diffusion for equimolar
counter diffusion assuming that nitrogen is also diffusing. Take diffusivity at
prevailing conditions are 2.30 x 10
-5
m
2
/s.
07
Q.2 (a) Define N and J type flux. What is the difference between N and J? 03
(b) For equimolar counter diffusion show that D AB = DBA 04
(c) Explain the film theory for mass transfer co-efficient. 07
OR
(c) Explain molecular diffusion in gases in detail. Also discuss steady state
diffusion of A through non diffusing B.
07
Q.3 (a) State characteristics of various types of packing. 03
(b) Describe the working of wetted wall tower. 04
(c) A packed tower is designed to recover 98% CO2 from a gas mixture containing
10% CO2 and 90% by volume air using water. The equilibrium relation used is
y? = 14x?, where, y?= kg CO2/kg dry air and x? = kg CO2/kg water. The water
to gas rate is kept 30% more than minimum value. Calculate actual mole ratio
of water to solute free gas.
07
OR
Q.3 (a) What is minimum liquid ? gas ratio in case of gas absorption? 03
(b) State selection criteria for solvent in extraction. 04
(c) Define F-type and k-type mass transfer coefficients. Also derive the
relationship for steady state equimolar counter diffusion between F and k type
coefficients.
07
Q.4 (a) Write short note on Absorption factor. 03
(b) Define: (i) Weeping (ii) Dumping (iii) Flooding (iv) Tray efficiency 04
(c) 150 kg of nicotine-water solution containing 1% nicotine is to be extracted
with 250 kg of kerosene at 20?C. Water and kerosene are essentially
immiscible in each other. Determine the % extraction of nicotine after single
stage. The equilibrium relationship is Y* = 0.798X, where X and Y* are
expressed as kg nicotine/kg kerosene and kg nicotine/kg water respectively.
07
2
OR
Q.4 (a) Outline the industrial applications of leaching 03
(b) How the height of absorption column is determined? 04
(c) Differentiate between Packed Towers and Tray Towers. 07
Q.5 (a) Define HTU, NTU and give its significance. 03
(b) Discuss the concept with principle of crystallization. 04
(c) Explain selection criteria for choice of solvent in case of gas absorption. 07
OR
Q.5 (a) Define selectivity of solvent used in liquid extraction. Draw a neat sketch of
the Shanks system for countercurrent multiple contact.
03
(b) State and discuss the various techniques for achieving super saturation with
suitable example.
04
(c) Explain construction and working of Swenson-Walker Crystallizer with the
help of a neat sketch.
07
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This post was last modified on 20 February 2020