Register Number
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act,1956)
Course & Branch :B.Tech - CHEM
Title of the Paper :Mass Transfer – I
Sub. Code :SCHX1025 (2010)
Date :31/10/2012
Max. Marks:80
Time : 3 Hours
Session :FN
_______________________________________________________________________________________________________________________________
1.
PART - A
(10 x 2 = 20)
Answer ALL the Questions
Define diffusion and what are the types of diffusion.
2.
Explain Ficks-Law of diffusion.
3.
Define Murphree efficiency.
4.
Name any three theories of Mass transfer.
5.
What is Molal Absolute Humidity?
6.
Explain about wet bulb temperature.
7.
Define free moisture and equilibrium moisture.
8.
Discuss the terms constant rate period and falling rate period.
9.
State Δ L law of crystal growth.
10. Define Nucleation.
PART – B
(5 x 12 = 60)
Answer ALL the Questions
11. (a) Prove DAB = DBA for equimolar counter diffusion in gases.
(b) Derive an equation for the steady state diffusion of A through
non-diffusing B.
(or)
12. (a) Ammonia diffuses through nitrogen gas under equimolal
counter diffusion at a total pressure of 1.013 x 105 pa and at a
temperature of 298K. The diffusion path is 0.15m. The partial
pressure of ammonia at one point is 1.5 x 104 pa and at the other
point is 5 x 103 pa. Diffusivity under the given condition is 2.3 x
10-5 m2/s. Calculate the flux of ammonia.
(b) Discuss the molecular diffusion in liquids.
13. (a) Explain penetration theory.
(b) Discuss Two-Phase Mass transfer.
(or)
14. Sulphur-di-oxide is absorbed from air into water in a packed
absorption tower. At a certain location in the tower, the mass
transfer flux is 0.027 kmol So2/m2h and the liquid phase
concentrations in mole fraction are 0.0025 and 0.0003
respectively at the two-phase interface and in the bulk liquid. If
the diffusivity of So2 in water is 1.7 x 10-9m2/s, determine the
mass transfer co-efficient Kc and film thickness.
15. Draw the various types of cooling tower arrangements and
explain in detail.
(or)
16. A mixture of nitrogen-acetone vapor at 800mmHg and 250C has
percentage saturation of 80%. Calculate (a) Absolute humidity
(b) Partial Pressure of acetone (c) Absolute molal humidity.
Assume vapor pressure of acetone at 250C as 190mmHg.
17. (a) How will you calculate the drying time under constant drying
conditions?
(b) What are the parameters that affect the drying rate during
constant rate?
(or)
18. With a neat sketch explain the rotary dryer.
19. (a) Explain the classification of crystallizer.
(4)
(b) Explain the principle, construction and working of any one
crystallizer with a neat diagram.
(8)
(or)
20. Sodium acetate solution is available at a temperature of 700C
with a solute content of 58%. Find out (a) Percentage saturation
(b) yield of crystal if 2000 Kg of this solution is cooled to 100C
(c) Percentage yield.
Data:
Solubility at 70C = 146 gms of sodium acetate/100 gms of water
Solubility at 10C = 121 gms of sodium acetate/100 gms of water