University Of Pune Question Paper
S.E. (Chemical) (Semester – II) Examination, 2011
MECHANICAL OPERATIONS
(2003 Course)
Time : 3 Hours Total Marks : 100
Instructions : 1) Answer three questions from Section I and three
questions from Section II.
2) Answers to the two Sections should be written in
separate books.
3) Neat diagrams must be drawn wherever necessary.
4) Use of logarithmic tables, slide rule, Mollier charts,
electronic pocket calculator and steam tables is
allowed.
5) Assume suitable data, if necessary.
SECTION – I
1. a) Differentiate differential and cumulative analysis with proper examples. 6
b) The screen analysis shown applies to a sample crushed quartz. Estimate :
i) Average particle size of the product
ii) Specific surface area for the product using both differential and cumulative
analysis :
Data : Density of sample = 2.65 gm/CC, a = 2, b = 3.5. 10
Mesh No. 4/6 6/8 8/10 10/14 20/28 28/35
Aperture size
(CMS) 0.4013 0.2844 0.206 0.1409 0.0711 0.0503
Mass Fraction
retained on screen 0.0251 0.125 0.3207 0.257 0.0538 0.021
c) Explain the need of size reduction in process industries. 2
OR
2. a) Why the gyratory crushers are more widely used than jaw crushers ? 4
b) Differentiate crushing efficiency and mechanical efficiency. 4
c) In a certain blake jaw crusher it is necessary to apply a maximum force of
1000 Kgs. at a toggle point. The toggle block is 80 cms from the pivot point.
The angle between pitman and toggle is 85°, what will be the force on pitman ?
What is the force on particle at distance 35 cm from the pivot ? Derive the
expression that you have used. 10
3. a) Describe the working of belt conveyor with suitable sketches. List advantages
and disadvantages of belt conveyors and typical applications. 8
b) Describe with a sketch the working of a screw conveyor. List advantages and
disadvantages. 8
OR
4. Write short notes on :
a) Closed loop pneumatic conveying system.
b) Chain and flight conveyor.
c) Bucket elevator.
d) Apron conveyor. 16
5. a) Describe the types of mixers for pastes and plastic mass. 8
b) With the help of neat sketches distinguish the axial flow and radial flow impeller. 8
OR
6. a) A silty soil containing 14% moisture was mixed in a large muller mixer with
10 weight percent of a tracer consisting of dextrose and picric acid. After
4 min. of mixing 10 random samples were taken from the mixture and analysed
for tracer material. The measured concentrations in the same were, in weight
percent tracer 10.28, 9.20, 7.8, 11.03, 10, 11.51, 9.25, 9.65, 10.65, 10.77. Calculate
the mixing index Ip of the operation. 8
b) What is degree of mixing and rate of mixing in case of mixing of dry solids
and derive the expressions. 8
-3- [3962] – 340
SECTION – II
7. a) A plate and frame press filtering a slurry, gave a total of 25 m3
of filterate in
30 minutes and 35m3
in 60 minutes when filtration was stopped. Estimate the
washing time in minutes if 10m3
of wash water are used. The resistance of the
cloth can be neglected and a constant pressure is used through-out. 10
b) Explain construction, working and applications of Rotary Drum vacuum
filter. 8
OR
8. a) Explain leaf filter and filter press in detail. 8
b) A constant pressure filtration tests gave data that can fit an expression :
9.3V 8.5
dV
dt = +
where t in seconds, V in liters. If the resistance of the filter medium is assumed
unaffected with pressure drop and the compressibility cofficient of the filter
cake is 0.3, what will be the time taken for the collection of 3.5 liters of filtrate
at a filtration pressure twice that used in the test ? 10
9. a) Explain the sink and float method and differential settling method in sorting
classifiers. 8
b) Explain principle, construction and working of the electrofloation plant. 8
OR
10. a) Describe aggregative and particulate fluidization. If fine catalyst particles are
fluidized in water then which type of fluidization would be observed ? 8
b) A tube of 0.05m2
cross-sectional area is packed with spherical particles up to
a height of 0.25 m. The porosity of the bed is 0.35. It is desired to fluidize the
particles with water (ρ =1000 kg/m3
, 3 10− μ = Pa-sec). Calculate minimum
velocity of fluidization by Ergun’s equation.
Data : Diameter of particles = 0.01 m
Density of solid particles = 2600 kg/m3
. 8
11. a) Describe with neat sketches the operation of a patch centrifuge and continuous
centrifuge. 8
b) Describe with a neat sketch the sedimentation operation. Also sketch typical
commercial equipment. 8
OR
12. Write short notes :
a) Cyclone separator
b) Scrubbers
c) Fabric filter
d) Mineral Jig. 16
————
S.E. (Chemical) (Semester – II) Examination, 2011
MECHANICAL OPERATIONS
(2003 Course)
Time : 3 Hours Total Marks : 100
Instructions : 1) Answer three questions from Section I and three
questions from Section II.
2) Answers to the two Sections should be written in
separate books.
3) Neat diagrams must be drawn wherever necessary.
4) Use of logarithmic tables, slide rule, Mollier charts,
electronic pocket calculator and steam tables is
allowed.
5) Assume suitable data, if necessary.
SECTION – I
1. a) Differentiate differential and cumulative analysis with proper examples. 6
b) The screen analysis shown applies to a sample crushed quartz. Estimate :
i) Average particle size of the product
ii) Specific surface area for the product using both differential and cumulative
analysis :
Data : Density of sample = 2.65 gm/CC, a = 2, b = 3.5. 10
Mesh No. 4/6 6/8 8/10 10/14 20/28 28/35
Aperture size
(CMS) 0.4013 0.2844 0.206 0.1409 0.0711 0.0503
Mass Fraction
retained on screen 0.0251 0.125 0.3207 0.257 0.0538 0.021
c) Explain the need of size reduction in process industries. 2
OR
2. a) Why the gyratory crushers are more widely used than jaw crushers ? 4
b) Differentiate crushing efficiency and mechanical efficiency. 4
c) In a certain blake jaw crusher it is necessary to apply a maximum force of
1000 Kgs. at a toggle point. The toggle block is 80 cms from the pivot point.
The angle between pitman and toggle is 85°, what will be the force on pitman ?
What is the force on particle at distance 35 cm from the pivot ? Derive the
expression that you have used. 10
3. a) Describe the working of belt conveyor with suitable sketches. List advantages
and disadvantages of belt conveyors and typical applications. 8
b) Describe with a sketch the working of a screw conveyor. List advantages and
disadvantages. 8
OR
4. Write short notes on :
a) Closed loop pneumatic conveying system.
b) Chain and flight conveyor.
c) Bucket elevator.
d) Apron conveyor. 16
5. a) Describe the types of mixers for pastes and plastic mass. 8
b) With the help of neat sketches distinguish the axial flow and radial flow impeller. 8
OR
6. a) A silty soil containing 14% moisture was mixed in a large muller mixer with
10 weight percent of a tracer consisting of dextrose and picric acid. After
4 min. of mixing 10 random samples were taken from the mixture and analysed
for tracer material. The measured concentrations in the same were, in weight
percent tracer 10.28, 9.20, 7.8, 11.03, 10, 11.51, 9.25, 9.65, 10.65, 10.77. Calculate
the mixing index Ip of the operation. 8
b) What is degree of mixing and rate of mixing in case of mixing of dry solids
and derive the expressions. 8
-3- [3962] – 340
SECTION – II
7. a) A plate and frame press filtering a slurry, gave a total of 25 m3
of filterate in
30 minutes and 35m3
in 60 minutes when filtration was stopped. Estimate the
washing time in minutes if 10m3
of wash water are used. The resistance of the
cloth can be neglected and a constant pressure is used through-out. 10
b) Explain construction, working and applications of Rotary Drum vacuum
filter. 8
OR
8. a) Explain leaf filter and filter press in detail. 8
b) A constant pressure filtration tests gave data that can fit an expression :
9.3V 8.5
dV
dt = +
where t in seconds, V in liters. If the resistance of the filter medium is assumed
unaffected with pressure drop and the compressibility cofficient of the filter
cake is 0.3, what will be the time taken for the collection of 3.5 liters of filtrate
at a filtration pressure twice that used in the test ? 10
9. a) Explain the sink and float method and differential settling method in sorting
classifiers. 8
b) Explain principle, construction and working of the electrofloation plant. 8
OR
10. a) Describe aggregative and particulate fluidization. If fine catalyst particles are
fluidized in water then which type of fluidization would be observed ? 8
b) A tube of 0.05m2
cross-sectional area is packed with spherical particles up to
a height of 0.25 m. The porosity of the bed is 0.35. It is desired to fluidize the
particles with water (ρ =1000 kg/m3
, 3 10− μ = Pa-sec). Calculate minimum
velocity of fluidization by Ergun’s equation.
Data : Diameter of particles = 0.01 m
Density of solid particles = 2600 kg/m3
. 8
11. a) Describe with neat sketches the operation of a patch centrifuge and continuous
centrifuge. 8
b) Describe with a neat sketch the sedimentation operation. Also sketch typical
commercial equipment. 8
OR
12. Write short notes :
a) Cyclone separator
b) Scrubbers
c) Fabric filter
d) Mineral Jig. 16
————
0 comments:
Pen down your valuable important comments below