Maharashtra State Board of Technical Education 2012-6th Sem Diploma Chemical Engineering for in Subject Mass Transfer Operation (12297) - Question Paper
MSBTE Sample ques. Paper for Diploma in Chemical Engineering
Sixth Semester
Subject Mass Transfer Operation (12297)
Instructions:
12297
Marks: 100
Scheme - E Sample Question Paper Course Name : Diploma in Chemical Engineering Course code : C*H Semester : Sixth Subject Title : Mass Transfer Operation Time : 3 hours
1) All the questions are compulsory.
2) Figures to the right indicate full marks.
3) Assume suitable additional data if necessary.
Q.la) Attempt any THREE of the following: 12 Marks
a. Write Ficks Law of diffusion. Name and give units of flux in momentum, heat and mass transfer.
b. Write an expression for equimolar counter current diffusion with meaning of each term.
c. Give Gibbs's Phase Rule. What is meant by degrees of freedom? What are the degrees of freedom in Distillation?
d. Draw a neat boiling point and equilibrium diagram for a minimum boiling azeotrope.
Q.lb) Attempt any ONE of the following: 06 Marks
a. Draw the equilibrium diagram for a binary system having relative volatility equal to
2.3
b. Give the prmciple involved in steam distillation and give its applications.
Q.2 Attempt any TWO of the following: 16 Marks
a. A liquid mixture containing 50 mole % benzene and 50 mole % toluene is subjected to flash distillation at a separator pressure of 101.25 kPa to vaporize 50 mole % of feed. What will be the equilibrium composition of vapor and liquid?
Data:
|
X |
0 |
0.05 |
0.1 |
0.2 |
0.3 |
0.4 |
0.5 |
0.6 |
0.7 |
0.8 |
0.9 |
1.0 |
|
Y |
0 |
0.13 |
0.21 |
0.375 |
0.5 |
0.6 |
0.7 |
0.77 |
0.83 |
0.9 |
0.95 |
1.0 |
b. A wet solid is to be dried from 30% to 10% moisture under the constant drying conditions in five hours. If the equilibrium moisture content is 4% and the critical moisture content is 14%. How long it will take to dry solids to 6% moisture under the same conditions?
c. A solution of sodium nitrate in water contains 50% NaN03 by weight at 313 K (40C) temperature. Calculate the percentage yield of NaNC>3 crystals that may be obtained when temperature is reduced to 283 K (10C). Also calculate the yield of NaNC>3 crystals from 100 Kg of solution. Data: Solubility of NaNC>3 in water at 283 K (10C) is 80.18 Kg NaN03 per 100 Kg water.
Q.3 Attempt any FOUR of the following: 16 Marks
a. Methane diffuses at stead)7 state through the tube containing helium. At point 1 the partial pressure of methane is 55 kPa and at point 2 it is 15 kPa. The points 1 and 2 are 30 mm apart. Total pressure is 101.3kPa and temperature is 298K. Calculate the flux of methane at steady state for equunolar counter diffusion. Take the value of diffusivity as 6.75xl0'5 m2/s.
b. Explain penetration theory of diffusion.
c. What are the various methods of distillation? Which of them is best and why?
d. Give the names and four important properties of packings used in a Packed tower.
e. Ammonia from ammonia- air mixture is to be absorbed in an absorption tower using water as a solvent. Data for absorption system is as follows:
Air flow rate - 200 Kg/hr Liquid phase composition -
At the top of packing - 0.000013 Kg ammonia/ Kg water At the bottom of packmg - 0.0006 Kg ammonia/ Kg water Gas phase composition
At the bottom of packing - 0.0084 Kg ammonia/ Kg inert gas At the top of packing - 0.0044 Kg ammonia/ Kg inert gas Calculate the flow rate of water entering the absorption to we.
Q.4 a) Attempt any THREE of the following: 12 Marks
a. Draw a neat diagram of velocity vs pressure drop in a packed column and show
loading point and flooding point.
b. Compare packed column and plate column on the following points:
i) pressure drop ii) cost iii) handling corrosive liquids iv) handling very small volume of liquids
c. Compare extraction and distillation on the following points:
1) punty ii) cost in) boiling point of liquid iv) physical property involved.
d. Draw a neat diagram and explain working of mixer settler.
Q.4 b) Attempt any ONE of the following: 06 Marks
a. Write equation for q line and draw various types of q lines for different feed conditions.
b. Picric acid is to be extracted from benzene if aqueous solution contains 0.2 moles of picric acid per litre calculate the volume of benzene with which on litre of solution must be extracted in order to form 0.02 moles of picric acid per litre.
Also calculate the recovery of picric acid from the aqueous solution.
K = distribution coefficient = Ce / Cr = 0.505 Q.5 Attempt any TWO of the following: 16 Marks
a. 1000 kmollir of an ethanol - propanol mixture containing 60 mole % ethanol is to be
separated in a continuous plate column operating at 101.325 kPa total pressure. The desired terminal composition m terms of mole fraction of ethanol are- Xd = 0.92 and Xw = 0.07
The feed is admitted at its boiling point. The reflux flow rate is four tunes the mount of top product, find the number of theoretical plates required for the separation. Relative volatility of ethanol - propanol system may be taken as 2.
b. Derive the expression for calculating total time required for drying a wet material from initial moisture content Xi to final moisture content X2 where X2 is greater than equilibrium moisture content and less than critical moisture content.
c. Draw a triangular diagram and describe its use in extraction.
Q.6 Attempt any FOUR of the following: 16 Marks
a. Define the following terms:
i) free moisture content ii) bound moisture content
ii) critical moisture content iv) equilibrium moisture content
b. Describe the working of a tray dryer.
c. Draw a neat diagram of a spray dryer and name its different parts.
d. Draw a neat diagram to show the effect of temperature on solubility of solute and various methods of super saturation of these solutions
e. Draw a neat diagram of Swenson walker crystallizer and describe its working.
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Attachment: |
| Earning: Approval pending. |
