Download SGBAU (Sant Gadge Baba Amravati university) B-Tech/BE (Bachelor of Technology) 6th Sem Poly Plast Chemical Engineering Operation II Previous Question Paper
11126 : Chemical Engineering Operation - 11 (Mass Transfer Operation) : 6 PP 01
P. Pages : 2 ? AW - 3252
Time : Three Hours IMAM? ??y
Max. Marks : 80
Notes :
b)
b)
b)
b)
I Answer Three question from Section A and Three question from Section B.
2 Assume suitable data wherever necessary.
3. Diagrams and chemical equations should be given wherever necessary.
4. Illustrate your answer necessary with the help of neat sketches.
5 cell phone is not allowed.
6 Discuss the reaction, mechanism wherever necessary.
7 Use of pen Blue/Black ink/re?ll only for writing the answer book.
SECTION - A
Derive the expression of cquimolar counter current diffusion for molar mass ?ux in terms 7
of diffusivity.
In an Oz-Nz gas mixture at 101.3 KPa and 298?K the concentration of 02 at two phases 2mm 7
apart are 10 and 20% by volume respectively. Calculate the molar ?ux of di?usion of
oxygen (02) for the cases where (N2) nitrogen is non-diffusing and there is equimolar
counter diffusion of the two gases.
Diffusivity ofOz in N2 is 1.81x10?5m2 /sec.
OR
Distinguish between molecular diffusion and eddy diffusion with suitable example.
Describe with the help of schematic diagram of Winkelman's experiment used for
determination of diffusivity of volatile organic liquid into air. Derive the expression of
dif?isivity with the help of Winkelman's experiment.
Draw a neat sketch of Wetted wall column and describe it's use for determination of gas 7
?lm mass transfer coef?cient.
What are the corresponding groups in mass transfer to those of Prandtl and Nusselt number 6
in heat transfer operation?
0R
Write down the salient points of two ?lm theory in detail. What are the assumptions of 13
Whitman's two ?lm theory?
What is a selection criteria for good solvent used in gas absorption process?
Discuss minimum liquid to gas ratio (L /V) in gas absorption operation.
OR
A gas absorber is to be designed to handle 38.73 kg mole/hr of coal gas containing 2% by 13
volume benzene. The coal gas enters at a temperature of 300? K and 1 atm pressure. How
does 95% of benzene should be recovered by the solvent. The solvent enters at 300? K
containing 0.005 mole ?ac?on of benzene and has an average moleculax weight of 260.
Calculate the circulation rate of solvent the column is to operate at 1.5 times the minimum.
The equilibrium data is
Y =ng _X_
1+Y 1+X
Where
Y= Mole ratio of benzene to dry gas X = Mole ratio of benzene to solvent
AW - 3252 1 P.T.0
7. a)
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8. a)
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9. a)
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10. a)
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11. a)
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12. a)
13)
SECTION ? B
For ?ash distillation show that the equdion 01 operating line in terms of fraction of feed
vaporized is given by
\?=_.L:?)(+2?L
f f
What do you mean by azeotrope and azeotropic distillation discuss with suitable example?
0R
Describe the recti?cation on ideal plate with the help of material balance over it. Derive
expressions of operating line equatuorlr, of rectifying and stripping section of fractionating
column on the basis of material balance.
What is ideal stage? Describe Murphrec stage ef?ciency with the help of neat sketch.
Discuss in detail the steam distillation.
What do you understand by minimum lC?UX ratio (Rm)? Derive the necessary equation for
calculation of minimum re?ux ratio.
OR
When a mixture of hexane and ethyl benzene is being fed to distillation column at 200 kg
moles 'hr with 42% hexane in 11. the top .Jistillate product containing 97% hexane and bottom
product 1.1% hexane
Calculate:-
i) kg moles of hexane obtained per lmur at the top Ofcolumn.
ii) kg moles of bottom pruducl ofcuiumn. Find out minimum number oftheoretical
plates at total re?ux using Fens?: equation.
What is Rault's law? How does it used ?1?) established vapour - liquid equilibrium data?
A lOOkg batch of granuleu :;olids commuting 30?3"? moisture is to be dried in a tray drier to
16% moisture by passing a current of air at .?~50?K across it surface at a velocity of 1.8
, . .. . _ 7
meter'sec. 1fthe constant rate of drying under these condmons IS 0.7x 10 3kg / m?.sec and
the crxtical moisture content is 1591. (Talculate the drying time.
Drying surface = 0.03 mz/kg of dry \?J?Cight
What is equilibrium moisture? Describe working ttf?spray drier with the help neat sketch.
0R
De?ne the following terms.
i) Humidity ii) Relative Humidity
iii) Percentage Humidity iv) Dew point
Explain the curve plotted between rave ot?drying and moisture content in brief.
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AW - 3252 2
This post was last modified on 10 February 2020