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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEMESTER VI (OLD).EXAMINATION WINTER 2016
Subject Code: 160503 Date: 22/10/2016
Subject Name: Process Equipment Design-I
Time: 10:30 AM to 01:30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 Hexane at 37.8 °C is pumped through the system at a rate of 9.09 m3/h. The tank
is at atmospheric pressure. Pressure at the end of discharge line is 345 kPa g. The
discharge head is 3.05 m and the suction lift is 1.22 m above the level of liquid in
the tank. The friction loss in suction line is 3.45 kPa and that in the discharge line
is 37.9 kPa. The mechanical efficiency of the pump is 0.6. The density of hexane is
659 kg/m3 and its vapor pressure at 37.8 °C is 33.71 kPa. Calculate (NPSH)A
and Power required by the centrifugal pump.
07
Write a short note on fluid allocation in shell and tube heat exchanger. 07
Q.2 Discuss the Process Design of Fans and compressor. 07
Discuss the advantages and disadvantages between fixed tube sheets, U-tube and
floating head type of heat exchanger.
07
OR
Discuss in detail about criteria of selection between kettle type and thermosyphon
reboiler.
07
Q.3 Discuss the design steps for the calculation of tube side and shell side heat transfer
coefficient.
07
Write a short note on air cooled heat exchangers and air heaters. 07
OR
Q.3 A feed stream having flow rate of 200 kg/h and containing 20 mass acetic acid
in water is to be extracted at 25 oC with 400 kg/h of recycled MIBK (Methyl
IsoButyl Ketone) that contains 0.1 acetic acid and 0.01 water. The aqueous
raffinate is extracted down to 1 acetic acid. Calculate Ntor considering MIBK
and water as partially miscible liquids and Ntor considering MIBK and water as
completely immiscible liquids and equilibrium curve as straight line.
Data for equilibrium curve:
X 0 0.0285 0.117 0.205 0.262 0.328 0.346
Y 0 0.0187 0.089 0.173 0.246 0.308 0.336
Data for operating curve:
X 0.2 0.14 0.08 0.01
YS+1 0.085 0.06 0.035 0.001
Data in terms of mass ratio:
of Acetic acid/kg of water) 0 0.0299 0.1364 0.2708
of Acetic acid/kg of MIBK) 0 0.0196 0.1039 0.2354
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Q.4 Explain the method for determining minimum reflux ratio for binary distillation. 07
With suitable example explain the concept of selection of operating pressure for
distillation.
07
OR
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Q.4 A saturated liquid, consisting of phenol and cresol with some xylenols, is
fractioned to give a top product of 95.3 mole phenol. Metacresol is heavy key
and phenol is light key component. Total condenser is used. The composition of
the top product and of the phenol in the bottom is given. Complete the material
balance over the still for a feed rate of 100 kmol/h and Calculate the minimum
reflux ratio by Underwood's method.
Component αav
Feed,
mole
Top product,
mole
Bottom product,
mole
Phenol 1.98 35 95.30 5.24
o-Cresol 1.59 15 4.55
m-Cresol 1.00 30 0.15
Xylenols 0.59 20
07
Discuss in details the various factors considered for the selection of tray. 07
Q.5 Discuss in details the selection criteria for different absorption equipment. 07
With neat sketch explain the various types of random packings used in packed
column.
07
OR
Q.5 Venturi scrubber is planned for absorbing NO gases from the exits gas stream of
nitric acid plant by using 10 NaOH solution (by mass). Exist gas mixture,
leaving the absorber of nitric acid plant, is having the following composition.
Volumetric flow rate of exist gas mixture 40586.5 NO concentration in
gas mixture 1821.5 ppm, Discharge pressure of gas from venturi atmospheric,
Solvent to gas ratio 1.5 Temperature of gas mixture entering the venture
scrubber 50 oC, Density of 10 NaOH solution 1108.9 kg/m3, Equilibrium
mass of NO per 100 mass of H2O 0.030, Average molar mass of gas mixture
entering scrubber 28.43 kg/kmol, Throat velocity of gas phase 100 m/s.
Determine throat diameter of venture scrubber removal of NO gases
pressure drop in venture scrubber. Use following design equations.
Fractional solute removal











M
M
L
mG
mx y
y
y y
1
1 2 2
1
1 2
Venturi pressure drop 3 2 0.133 0.78 P 2.584 10 v A L G G th
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