dian forest Service IA-JGPT-M-DIFO-A I
CHEMICAL ENGINEERING Paper I (CONVENTIONAL)
ITime allowed: Three Hours I IMaximum Marks: 200 I

Question Paper Specific Instructions
Please read each oftke following instructions carefully before attempting qlU!stions:
TJwre are EIGHT questions in all, out ofwhich FIVE are to be attempted.
Questions no. 1 and 5 are compulsory. Out of the remaining SIX questions, THREE are to be attempted selecting at least

ONE question from each ofthe two Sections A and B.
Attempts ofquestions shall be counted in chronological order. Unless struck off, attempt ofa question shall be counted even
ifattemptedpartly. Anypageorportion ofthepageleftblankintheAnswerBook mustbeclearlystruckoff.
Allquestionscarryequalmarks. Thenumber ofmarkscarriedby a question /part is indicated against it.
Answers must be written in ENGLISH only..
Unless otherwise mentioned, symbols and notations have their: usual standard meanings.
Assume suitable data, ifnecessary and indicate the same clearly.
Neat sketches may be drown, whereuer required.
SECTION A
Q.l. Answer all parts
(a)(i)Distinguish clearly between laminar flow and turbulent flow. 4
(ii)Explain the terms: 'Mach number' and 'Stagnation temperature' in connection with flow of
compressible fluids. 4

Why is the counter current flow heat exchanger more efficient than the parallel flow heat
exchanger? Under what conditions do these exchangers become equally efficient 4
Why are baffles and tie rods used in shell and tube heat exchanger? In order to enhance the
velocity of fluid flowing through tube side, what modification in the exchanger would you
suggest? Give reasons. 4

Write down different mass transfer coefficients and related driving forces indicating their units for
interphase mass transfer. 8
State the disadvantages of 'Forced draft' cooling tower. Explain Evaporative cooling. 8
Explain about particulate fluidization and pneumatic conveying. 8

Q.2(a) A Newtonian fluid is flowing through a pipe of circular cross-section. The fluid is incompressible and
the flow is laminar, steady and fully developed. Show that the velocity profile is a parabola. 10

a filtration process, a general relationship can be written as
<img src='./qimages/1192-2b.jpg'>
where, V is total volume collected in time theta, alpha is specific cake resistance, Rm is filter medium
resistance, c is concentration of solid in slurry, mew is the viscosity of the filtrate and VP is the pressure
drop. Experiment was carried out at a constant pressure drop of 5x10 4 N/m2 with a slurry
containing 20kg/m3 of CaC03 in water. The plot of theta/V vs. gave the slope of the curve to be
12·5 S/lit2 and the intercept to be 26.5 S/lit. If the filter area is 0·09 m2 and viscosity of the filtrate is
0·001 kg/m.s, calculate the specific cake resistance and filter medium resistance. 10

Define "angle of nip" for two roll crushers. Develop an expression for angle of nip in terms of radii of
the rolls, size of the feed, and gap between the rolls. 20

Q.3(a) Explain with examples, the terms:
Natural convection and Forced convection. 5
In a double pipe heat exchanger, hot water flows at a rate of 50,000 kg/hr and gets cooled from 95 to
65°C. At the same time 50,000 kg/hr of cooling water at 30°C enters the heat exchanger. The overall
heat transfer coefficient is 2270 W/m2K. Determine the heat transfer area and effectiveness of the
heat exchanger assuming the two streams are in parallel flow. Assume for both the fluids
Cp 4·2*KJ/kg.K 20

Define Geometric or Angle or view factor in radiation between two large parallel plates. Under what
circumstances the value becomes one or zero? Deduce the expression for total heat flux between two
parallel grey surfaces which are large compared to their distance apart. 15

Q.4.(a) Draw a neat diagram of a Sieve tray column, showing the internals, and explain the functions of the
internals. 15
the operation of a cooling tower, define the terms temperature approach and cooling range.
How does the temperature approach affect the size of a cooling tower? 5

(c)Derive the analytical expression for determination of minimum number of theoretical plates
required in plate type column for distillation of a binary mixture assuming the relative volatility to
be constant. 20


SECTIONB

Q.5.(a) Describe Bourdon tube with its working principle and areas of application. 10
(b)Explain about membrane separation process with its working principle, which may be used to
separate macromolecules of proteins, polymers and starches. 10
(c)Transportation lag is often present in industrial control systems. Explain it with its impact on the
control of process systems. 10
Describe three types of compensations, which are commonly used to reinforce the area around an
opening in a pressure vessel. 10
Q.6.(a)Consider a membrane separator element which is used to separate a gas mixture of A and B. The
unit is being operated continuously. The feed flow rate is 2x103 cm3(STP)/s and mole fraction of A
in feed is 0·413. The feed side pressure is 80cm Hg and permeate side pressure is 20cm Hg. Mole
fraction ofA in reject is 0·30. Membrane characteristics are as follows:
Membrane thickness= 2x10power-3cm
permeability of A=<img src='./qimages/1192-6a.jpg'>
Ratio of permeability of A to that of B 10.
Using complete-mixing model, calculate the mole fraction of A in permeate, fraction of feed
permeated, and area of the membrane in the separator unit. 20

Derive equation used in part 20

Q.7.(a)As per Code of Practice for design of mild cylindrical oil storage tanks, following equation is used to
calculate the thickness of cylindrical shell plates:
<img src='./qimages/1192-6a.jpg'>
minimum thickness of shell plates, mm
D=nominal diameter of tank, m
H=height from bottom of the course to the maximum possible oil filling height, m
G=specific gravity of liquid to be stored
S=allowable stress of material, N/mm2
E=weld joint efficiency factor
Derive the above equation. 20

cylindrical large oil storage tank is used to store 1000 m3 of liquid petroleum products. Determine
its optimum diameter to height ratio so that total cost is minimum.
Cs=Cost of sides per m2 area
Ch=Cost of head or top cover per m2 of projected area =1·5Cs
Cb=Cost oft he flat bottom per m2 area= 0·75 Cs 20

Q.8.(a)Describe Bode diagrams used to represent the frequency response characteristics of a system.
Construct Bode diagram of a first order system. 25
(b)What do you understand by feed forward control of chemical process? Explain with suitable
examples. 15