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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEMESTER-VI EXAMINATION SUMMER 2018
Subject Code:2163506 Date:28/04/2018
Subject Name:Unit Operations-II
Time:10:30 AM to 01:00 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

Define: Osmotic Pressure Permeability Membrane flux
03

Explain equipments used in storage of solids.
04

Classify Dryers used in Industries and explain any one with neat and clean diagram.
07
Q.2

What are the different flow modes involved in Hopper?
03

Give the advantages and disadvantages of Fluidization as a unit operation.
04

A Rotary counter current dryer is fed with ammonium nitrate containing moisture at the rate of 100 kg/min and discharge the ammonium nitrate with 0.2% moisture. The air enters at 135°C and leaves at 80 °C. The humidity of entering air being 0.007 kg H2O/ kg of dry air. The ammonium nitrate enters at 21 °C and leaves at 65°C. Neglecting radiation losses calculate the kg of dry air passing through the dryer and the humidity of the air leaving the dryer.
Specific heat of ammonium nitrate 0.45
Specific heat of dry Air 0.238
Specific heat of water vapor 0.48
07
OR

It is desired to dry a certain type of fiber board in sheets 0.131m X 0.162m X 0.071m from 58% to 5 moisture content (wet basis). Initially from laboratory test data with this fiber board, the rate of drying at constant rate period was found to be 8.9 kg/ m2 hours. The critical moisture content was 24.9% and the equilibrium moisture content was 1%. The fiber board is to be dried from one side only and has a bone dry density of 210 kg/m3. Determine the time required for drying. The falling rate period may be assumed linear.
07
Q.3

What are the methods of palletizing of solids?
03

Define: Bound Moisture Equilibrium moisture content Relative Humidity
04

Discuss various types of problems involved in Hopper designing.
07
OR
Q.3

Discuss about Geldart's Powder Classification.
03

Explain Drying curve with suitable diagram.
04

Enlist different types of conveyors used in industry and explain Pneumatic Conveying System with suitable diagram.
07
Q.4

Explain working of Electrostatic Precipitator.
03

What are the conveyors and what are the benefits involved in using them?
04

Discuss Phenomena of concentration Polarization Reverse Osmosis in detail.
07
OR
Q.4

Discuss principal and working of Clarifocculator.
03
2

Discuss working of Belt Conveyor.
04

Explain the concept of Microfiltration and its industrial application in brief.
07
Q.5

What is the principle behind Drying? Discuss transport mechanism involved in drying.
03

Calculate the osmotic pressure of a solution containing 0.10 g NaCl/ 1000 g H2O at 25 °C
04

Explain Fluidization Process with suitable diagram of pressure drop and bed height vs. Superficial velocity for a bed of solids.
07
OR
Q.5

Give brief on Sand Filter.
03

Enlist various membrane modules available and explain modules used in Reverse Osmosis.
04

Discuss the methods of Granulation in brief.
07