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Indian Forest Services Examination····-··_
Sl. No. 771 D-VSF-L-URA
CHEMICAL ENGINEERING
Paper-I
I Time Allowed Three Hours I I Maximum Marks 200 I
INSTRUCTIONS
Candidates should attempt Question Nos. 1 and 5
which are compulsory, and any THREE of the
remaining questions, selecting at least
ONE question from each Section.
All questions carry equal marks.
Marks sllotted to parts of a question are
indicated against each.
Answers must be written in ENGLISH only.
Assume suitable data, if necessary, and indicate
the same clearly.
Neat sketches may be drawn, wherever required.
Section-A
1.Answer any four of the following
the Bernoulli's equation for
pumping water from underground
storage to the tank on the top of a
building. Explain the significance of
each term. 5
Explain clearly the fluid drag and
pressure drop due to friction. 5

(b)Explain crushing and grinding
principles. What is work index? 10
(c)Explain the following
(i)Relative volatility 3
(ii)Fick's law of diffusion 3
(iii)Humidification and dehumidification 4
(d)Explain the following
LMTD and effectiveness factor 4
(ii)Analogy between heat and momentum transfer 3
(iii)Free and forced convections 3
(e)Explain briefly the concepts of
compressible and incompressible flows. 10

2.(a)Explain with a neat sketch the working
principle of spray dryer. 20
(b)Explain the principles of drying. 20

3.By what percentage would rate of absorption
be increased or decreased by increasing total
pressure from 100 to 200 kN/m2 in the
following cases?
(a)The absorption of ammonia from a
mixture of ammonia and air containing
10% of ammonia by volume using pure
water as solvent. Assume that all the
resistance to mass transfer lies within
the gas phase 20
(b)The same condition as the
absorbing solution exerts a partial vapor
pressure of ammonia of 5 kN/m2 20
Assume that if pressure is doubled, the
diffusivity is halved.

4.Liquid oxygen is distributed by road in a
large spherical insulated vessel, 2m internal
diameter,well-lagged on the outside. What
thickness of magnesia lagging of thermal
conductivity 0.07 W/m must be used so
that not more than of the liquid oxygen
evaporates during a journey of 2.78 hours if
the vessel is initially 80% full? 40
Latent heat of vaporization of
oxygen= 215 kJ/kg
Boiling point of oxygen 90K
Density of liquid oxygen 1140kg/m3
Atmospheric temperature 288 K
Heat transfer coefficient from outside
lagging to atmosphere= 4·5 W/m2 K
Section-S
5.Answer any four of the following
(a)Explain the mechanical properties of
the more common materials used in
the construction of chemical process
equipment. 10
(b)What are the various membrane
processes? Explain the working
principle of each membrane process. 10

(c)What are the important points to be
considered for design of underground
storage tank for higher pressure? 10
(d)What are the desirable properties of thermocouples for industrial use? Explain. 10
Explain about control valve construction. 10

6.(a)What are the various sources of fouling
of reverse osmosis membrane? 20
(b)Explain how fouling of reverse osmosis
membranes can be prevented. 20
7.(a)Explain how skirt supports are designed. 20
(b)Explain the various methods of designing reinforcement for a nozzle. 15
(c)Explain the merits and demerits of flat and elliptical heads. 5
8.(a)Explain the working principles of constant-area flowmeter
and variable area flowmeter with neat sketches. 20
(b)Explain the response of first-order
system in series for non-interacting
system and interacting system. 20