Indiabix - Equipment and Plant Design

Question 1

Fresh water carrying pipelines in chemical industries are
coloured with __________ color.

A. sea green
B. brown
C. yellow
D. red

Answer 1

A. sea green

Question 2

Which of the following material is seldom used for
pressure vessel construction?

A. Rimmed still
B. Mild steel
C. Killed steel
D. Semi-killed steel

Answer 2

A. Rimmed Still

Question 3

The ratio of shear stress to shear strain is called

A. bulk modulus
B. shear modulus
C. modulus of rigidity
D. modulus of elasticity

Answer 3

B. shear modulus

Question 4

25 per cent cut segmental baffle means that the baffle

A. height is 75% of the I.D. of the shell.
B. height is 25% of the I.D. of the shell.
C. spacing is 75% of its height.
D. width is 25% of its height.

Answer 4

A. height is 75% of the I.D. of the shell.

Question 5

Liquid/petroleum fuel storage tanks are built underground
(as in case of petrol pumps), when the storage capacity is
less than __________ kilolitres.

A. 20
B. 30
C. 45
D. 85

Answer 5

C. 45

Question 6

Le/D for fully open globe value may be around

A. 10
B. 25
C. 75
D. 300

Answer 6

D. 300

Question 7

Leg support is

A. the most suitable for thick vertical vessel.
B. same as bracket support.
C. provided usually for vessels of much smaller
height than skirt supported vessels.
D. all (a), (b) and (c).

Answer 7

D. all (a), (b) and (c).

Question 8

Pick out the wrong statement pertaining to the use of
valve tray, seive tray and bubble cap trays in continuous
distillation column.

A. Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be
handled and a positive liquid seal is essential at all flow rates.
B. Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for seive and valve trays than the
bubble cap.
C. Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.
D. Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible
operating range.

Answer 8

C. Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.

Question 9

With increase in the number of shell passes, the value of
FT

A. increases
B. decreases
C. remains same
D. remains same, only if the number of tube passes
does not change.

Answer 9

A. increases

Question 10

Holes of a sieve tray are arranged in triangular pitch of
__________ times the hole diameter.

A. 1.5 to 2
B. 2.5 to 5
C. 5 to 10
D. 10 to 15

Answer 10

B. 2.5 to 5

Question 11

In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm.

A. 3-5
B. 5-11
C. 8-15
D. 12-18

Answer 11

B. 5-11

Question 12

The stress developed in a material without any permanent set is called the

A. ultimate stress
B. yield stress
C. elastic limit
D. breaking stress

Answer 12

C. elastic limit

Question 13

In a shell and tube heat exchanger, the ‘tube pitch’ is defined as the

A. O.D. of the tube for square pitch.
B. shortest distance between two adjacent tube holes.
C. shortest centre to centre distance between adjacent tubes.
D. none of these.

Answer 13

C. shortest centre to centre distance between
adjacent tubes.

Question 14

Which of the following is not a valid assumption in continuous binary distillation for calculating the number of
equilibrium stages by Mc-Cabe-Thiele’s method ?

A. Sensible heat changes for vapour & liquid are negligibly small.
B. Reflux is not a saturated liquid.
C. Molar latent heat of the two components are equal.
D. Heat of mixing of normal liquid is assumed to be zero.

Answer 14

B. Reflux is not a saturated liquid.

Question 15

The value of fouling factor depends upon the

A. characteristic of process fluid.
B. velocity of process fluid containing suspended solids.
C. suspended solids in the fluid.
D. all (a), (b) and (c).

Answer 15

D. all (a), (b) and (c).

Question 16

In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about
__________ cms.
A. 10
B. 20
C. 30
D. 35

Answer 16

A. 10

Question 17

Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having
the same size & number of tubes and operated at the same liquid flow rate.

A. 2
B. 1/2
C. 4
D. 8

Answer 17

D. 8

Question 18

To keep the power input constant for a stirred vessel
operating under fully developed turbulent flow conditions
(constant power number), if the impeller diameter is
increased by 20%, the impeller speed should be
decreased by a factor of

A. (1.2)3/2
B. (1.2)3/5
C. (1.2)2/3
D. (1.2)5/3

Answer 18

D. (1.2)5/3

Question 19

In a heat exchanger, shell side fluid velocity can be
changed by changing the tube

A. layout
B. pitch
C. both (a) & (b)
D. neither (a) nor (b)

Answer 19

C. both (a) & (b)

Question 20

Where does the maximum tensile strength occur in a thick
cylindrical vessel subjected to internal pressure ?

A. At the inner surface.
B. At the mid thickness of the cylindrical wall.
C. At the outer surface.
D. None of these.

Answer 20

A. At the inner surface.

Question 21

It is not desirable to design a heat exchanger for LMTD
correction factor, FT, of less than

A. 0.99
B. 0.95
C. 0.80
D. 0.55

Answer 21

C. 0.80

Question 22

A rivetted joint does not fail by __________ of rivets.

A. tearing
B. shearing
C. tearing of the plate across a row
D. none of these

Answer 22

D. none of these

Question 23

Triangular pitch tube layout as compared to square pitch
in a shell and tube heat exchanger

A. permits the use of less tubes in a given shell
diameter.
B. facilitates comparatively easier external cleaning
because of large clearance.
C. permits the use of more tubes in a given shell
diameter.
D. both (b) and (c).

Answer 23

C. permits the use of more tubes in a given shell
diameter

Question 24

Bracket supports are the most suitable for supporting
__________ vessels.

A. thick walled vertical
B. horizontal
C. thin shperical (e.g. Horton sphere)
D. none of these

Answer 24

A. thick walled vertical

Question 25

In a multipass shell and tube heat exchanger, the shell
side cross flow area does not depend upon

A. baffle spacing
B. clearance
C. pitch
D. none of these

Answer 25

D. none of these

Question 26

Two iron pipes of the same nominal diameter but different
schedule numbers will have the same

A. inside diameter
B. outside diameter
C. wall thickness
D. none of these

Answer 26

B. inside diameter

Question 27

Steam side heat transfer co-efficient for design
consideration under ordinary condition can be assumed
to be about __________ kcal/hr.m2.°C.

A. 1250
B. 2500
C. 7500
D. 15000

Answer 27

C. 7500

Question 28

Pick out the wrong statement

A. For all the cylindrical process vessels operating
above atmospheric pressure, formed heads are
used for closing the vessel.
B. Fouling factor of river water is less than that of sea
water.
C. Risers provided in bubble cap trays in the
distillation column facilitate the flow of both liquid
and vapor.
D. both (b) and (c).

Answer 28

D. both (b) and (c).

Question 29

Lessing ring is formed by the addition of a partition across
the centre of a raschig ring, which results in an area
increase of about __________ percent.

A. 5
B. 20
C. 35
D. 55

Answer 29

B. 20

Question 30

In chemical process equipments, the conical bottom
heads used, usually has an apex angle of

A. 20°
B. 40°
C. 60°
D. 80°

Answer 30

C. 60°

Question 31

Smaller sized packings are generally dumped to the
packed columns, and the large ones of size greater than
__________ mm are stacked individually, which provides
better control over bed porosity and offers lower gas
pressure drop.

A. 25
B. 50
C. 75
D. 150

Answer 31

C. 75

Question 32

Shell side heat transfer co-efficient in case of square pitch
as compared to the triangular pitch under similar condition
of fluid flow and tube size is

A. more
B. same
C. less
D. twice

Answer 32

C. less

Question 33

Correct use of ‘factor of safety’ is very important in
equipment design. It is defined as the ratio of the
A. ultimate stress to breaking stress.
B. ultimate stress to working stress.
C. working stress to ultimate stress.
D. none of these.

Answer 33

B. ultimate stress to working stress.

Question 34

The operating velocity in the absorption tower is usually
40-50% of the flooding velocity. Packed absorption towers
are normally designed for a pressure drop of about
__________ mm of water column per metre height of
packing.

A. 1-5
B. 20-40
C. 100-150
D. 1000-1500

Answer 34

B. 20-40

Question 35

__________ tray arrangement is recommended for
distillation column having diameter upto 4 ft.

A. Radial flow
B. Cross flow
C. Split flow
D. Cascade

Answer 35

B. Cross flow

Question 36

What is the value of ‘q’ for saturated liquid feed to a
distillation column ?

A. 0
B. <1
C. 1
D. >1

Answer 36

C. 1

Question 37

In perforated plate towers, the
A. hole sizes may be around 1/8” or 3/16”.

B. total hole area may be around 6 to 15% of tower
cross-sectional area.
C. pressure drop is less compared is similar bubble
cap towers.
D. all (a), (b) and (c).

Answer 37

D. all (a), (b) and (c).

Question 38

The main purpose of providing stepping on the trays is to

A. increase the residence time.
B. decrease the pressure drop.
C. facilitate handling of large flow rate of liquid.
D. improve the flow condition.

Answer 38

C. facilitate handling of large flow rate of liquid.

Question 39

The operating pressure drop range in a bag filter is about
__________ mm water gauge.

A. 50-150
B. 5-10
C. 500-1500
D. 1500-2500

Answer 39

A. 50-150

Question 40

The ends of a cylinderical vessel can be closed by a head,
which can be one of the four shapes. For the same
thickness, choose the one which can withstand the
highest pressure.

A. Flat plate
B. Hemispherical
C. Torispherical
D. Ellipsoidal

Answer 40

D. Ellipsoidal

Question 41

For laminar flow (NRe < 2100) in steel pipe, the optimum
inside pipe diameter is given by

A. Di, opt = 3 Q0.36 μ 0.18
B. Di, opt = 3.9 Q0.45 . ρ0.23
C. Di, opt = 7.6 Q0.36 . ρ0.9
D. Di, opt = 3 Q0.36 . ρ1.86 μ0.08

Answer 41

A. Di, opt = 3 Q0.36 μ 0.18

Question 42

Pick out the correct statement.
A. When highly corrosive fluids are to be handled,
the plate towers prove to be cheaper and easier
to construct than packed tower.
B. Packed towers are generally preferred over
plate towers, if the liquids have a foaming
tendency.
C. The pressure drop through the packed towers is
generally more than the pressure drop through
plate towers designed for same duty.
D. none of these.

Answer 42

B. Packed towers are generally preferred over
plate towers, if the liquids have a foaming
tendency.

Question 43

Wall thickness of schedule 40 pipe as compared to that of
schedule 80 pipe is
A. more
B. less
C. same
D. cither (a) or (b); depends upon the I.D. of the pipe

Answer 43

B. less

Question 44

Pick out the wrong statement pertaining to the design of a
basket type evaporator.
A. It is used for high viscosity liquor having large
rate of scaling.
B. The tube bundle is suspended on bracket.
C. There is no central downtake.
D. Downtake is formed by the annular space
between the bundle and the shell.

Answer 44

A. It is used for high viscosity liquor having large
rate of scaling.

Question 45

Pick out the wrong statement pertaining to the design of
the bubble cap tray of a distillation column to give stable
operation and even vapour distribution.

A. The pressure drop due to the caps & slots and the
static submergence should be as high as
practicable for reasonable operation.
B. Tendency towards stable operation is increased
by increasing the skirt clearance of the caps,
lowering the rate of liquid flow per unit plate width
or increasing the spacing between the caps.
C. The dimensionless ratio of liquid gradient to
pressure drop head caused by the bubble cap
assembly should be less than 0.4.
D. none of these.

Answer 45

D. none of these.

Question 46

Speed of the drum of the rotary vacuum filter normally
ranges from __________ rpm.

A. 0.1 to 2
B. 5 to 7
C. 3 to 8
D. 8 to 15

Answer 46

A. 0.1 to 2

Question 47

A stuffing box is used for

A. absorbing the contraction/expansion of pipeline
due to temperature changes.
B. prevention of fluid leakage around moving
parts.
C. facilitating smooth opening and closing of a valve.
D. reducing the resistance of fluid flow.

Answer 47

B. prevention of fluid leakage around moving
parts.

Question 48

Pressure drop (Δp) and the superficial gas mass velocity
(G) in case of packed absorption tower operating in the
preloading range are related as

A. Δp = G
B. Δp = G0.5
C. Δp = G2
D. Δp = 1/G0.6

Answer 48

C. Δp = G2

Question 49

In an agitated vertical cylinderical reaction vessel, the

A. ratio of liquid depth to tank diameter (i.e. the filling
ratio) recommended for most purposes is 1.
B. filling ratio for dispersing gas in a liquid is 2 for
sufficiently long contact period.
C. flat bottom and conical bottom vessels have low
agitation efficiency for agitation of heavy solids in
liquids.
D. dished bottom vessel has very high power
consumption.

Answer 49

D. dished bottom vessel has very high power
consumption.

Question 50

Needle valves are generally not used for

A. very large diameter pipes.
B. high pressure throttling service.
C. very accurate flow control.
D. smaller sizes of pipe.

Answer 50

A. very large diameter pipes.

Question 51

Height equivalent to a theoretical plate (HETP) is the
height of packing that will give the same separation as one
theoretical plate in gas-liquid mass transfer operations
like distillation, absorption/stripping and humidification/dehumidification. HETP which is
experimentally determined, depends upon the

A. flow rates of each fluid.
B. type and size of packing.
C. concentration of each fluid.
D. all a, b & c.

Answer 51

D. all a, b & c.

Question 52

Pick out the wrong statement.

A. Safety valves are provided in heat exchangers
for removal of non-conden-sables.
B. Liquid metals and dowtherm are used for very
high temperature heating.
C. In a shell and tube heat exchanger, high pressure
fluid is generally routed through the tube.
D. A loop seal or U-seal is provided in a vertical
condenser sub-cooler to prevent quick draining of
the condensate.

Answer 52

A. Safety valves are provided in heat exchangers
for removal of non-conden-sables.

Question 53

With increase in gas flow rate to fabric surface area ratio
(Nm3/hr/m2 fabric surface area), the size & the cost of a
bag filter

A. increases
B. decreases
C. remain unaffected
D. none of these

Answer 53

B. decreases

Question 54

A head comprises of straight flange section, corner torus,
section and central dished section. Crown radius and
knuckle radius in a head is related respectively to the

A. central dished section and corner torus
section.
B. corner torus section and central dished section.
C. central dished section and straight flange section.
D. straight flange section and corner torus section.

Answer 54

A. central dished section and corner torus
section.

Question 55

Number of evaporators which can be used in service in a
multiple effect evaporation system is limited by the

A. practical limit reached, due to low heat transfer
rate because of inadequate temperature
difference.
B. economic limit reached, when the plant cost
exceeds the saving of steam.
C. both (a) & (b).
D. neither (a) nor (b).

Answer 55

C. both (a) & (b).

Question 56

Which of the following is used to set the diameter of the
distillation column ?

A. Number of theorectical plates.
B. Static submergence.
C. Allowable vapour velocity.
D. Length of straight rectangular weir on cross-flow
tray.

Answer 56

C. Allowable vapour velocity.

Question 57

Ponchon Savarit method is based on the use of enthalpy
concentration diagram, which contains the bubble point
curve (saturated liquid curve), dew point curve (saturated
vapour curve) and equilibrium tie lines. As compared to
McCabe-Thiele’s method, this method

A. is more accurate in finding the number of
equilibrium stages.
B. accounts for the enthalpy changes in the process.
C. facilitates direct calculation of heat load on
reboiler & condenser from, the diagram used in
this method.
D. all ‘a’, ‘b’ & ‘c’.

Answer 57

D. all ‘a’, ‘b’ & ‘c’.

Question 58

The optimum size ratio for two mixed reactors in series
depends on the kinetics of the reaction and the conversion
level. For reaction orders more than one, the

A. equal sized reactors are the best.
B. smaller reactor should come first.
C. larger reactor should come first.
D. none of these.

Answer 58

B. smaller reactor should come first.

Question 59

In a shell and tube heat exchanger, tube side __________
of the mass velocity.

A. heat transfer co-efficient is proportional to 0.8th
power
B. pressure drop is proportional to the square
C. both ‘a’ & ‘b’
D. neither ‘a’ nor ‘b’

Answer 59

C. both ‘a’ & ‘b’

Question 60

Which of the following is not a graphical method (but is an
analytical method) for the calculation of theoretical
number of stages in case of continuous binary distillation?

A. Sorel-Lewis method.
B. McCabe-Thiele’s method.
C. Ponchon-Savarit method.
D. none of these.

Answer 60

A. Sorel-Lewis method.

Question 61

Saddle supports are used for supporting __________
vessels.

A. horizontal cylindrical
B. tall vertical
C. thick walled vertical
D. thick spherical

Answer 61

A. horizontal cylindrical

Question 62

The diameter of a propeller agitator used in agitation tank
ranges from __________ percent of the tank diameter
and its peripherial speed is normally 300 to 500
metres/minute.
A. 5 to 10
B. 15 to 30
C. 40 to 50
D. 55 to 75

Answer 62

B. 15 to 30

Question 63

In packed towers provided with saddle packing, liquid
redistributors are positioned at every __________ times
column diameter or 6 metres whichever is less.

A. 2-3
B. 5-8
C. 10-15
D. 20-25

Answer 63

B. 5-8

Question 64

Optimum reflux ratio in a continuous distillation column is
determined by the

A. maximum permissible vapour velocity.
B. flooding limit of the column.
C. total cost consideration (fixed cost of the
column plus the cooling water & steam cost).
D. none of these.

Answer 64

C. total cost consideration (fixed cost of the
column plus the cooling water & steam cost).

Question 65

Cooling water fouling factors vary in the range of 0.001 to
0.003

A. (BTU/hr.ft2 . °F)-1
B. (kcal/hr.m2 .°C)-1
C. (W/m2.°K)-1
D. (kcal/hr. m. °C)-1

Answer 65

A. (BTU/hr.ft2 . °F)-1

Question 66

Minimum recommended baffle spacing in a shell and tube
heat exchanger is about (where, D = shell diameter )

A. 0.2 D
B. 0.5 D
C. 0.66 D
D. 0.80 D

Answer 66

A. 0.2 D

Question 67

The maximum liquid gradient over a tray must not exceed

A. 0.5” -1.25”.
B. 2”-3.5”.
C. 5”.
D. half the tray spacing.

Answer 67

A. 0.5” -1.25”.

Question 68

An underdesigned steam trap will

A. waste steam.
B. destroy itself of acceleration wear due to rapid
recycling.
C. back up condensate and cause water hammer
in steam line.
D. none of these.

Answer 68

C. back up condensate and cause water hammer
in steam line.

Question 69

The slope of the feed line in distillation opeartion is given
by (where, q = fraction of the feed stream that is liquid.)

A. -q
B. -q/(1-q)
C. -q/(q-1)
D. none of these

Answer 69

B. -q/(1-q)

Question 70

Speed of industrial paddle agitator ranges from
__________ rpm.

A. 1 to 5
B. 20 to 100
C. 500 to 750
D. 1000 to 2000

Answer 70

B. 20 to 100

Question 71

__________ strain is measured using a ‘strain rosetter’.

A. Volumetric
B. Shear
C. Linear
D. none of these

Answer 71

C. Linear

Question 72

Thin spherical shells subjected to internal pressure,
develop __________ stresses.

A. radial
B.circumferential
C. both (a) & (b)
D. neither (a) nor (b)

Answer 72

A. radial

Question 73

With increase in the reflux ratio for a fixed production from
a continuous binary distillation column, the __________
decreases.

A. fixed charges initially
B. running cost of cooling water for condenser
C. vapour & liquid load both
D. running cost of steam for reboiler

Answer 73

A. fixed charges initially

Question 74

The slope of operating line in the rectifying section of a
distillation column is unity, if the reflux ratio is

A. 0
B. ∞
C. 1
D. minimum

Answer 74

B. ∞

Question 75

Vertical vessels are not supported by

A. brackets
B. skirts
C. columns
D. saddles

Answer 75

D. saddles

Question 76

With increase in pressure drop (for a given particle size),
the dust collection efficiency of a cyclone separator will

A. increase
B. decrease
C. remain unaffected
D. increase or decrease depending on the nature of
the dust.

Answer 76

A. increase

Question 77

Spherical shaped pressure vessel is considered to be the
most ideal, because it can

A. withstand higher pressure for a given metallic
shell thickness.
B. be fabricated very easily.
C. be designed without wind load considerations.
D. be supported very easily.

Answer 77

A. withstand higher pressure for a given metallic
shell thickness.

Question 78

An adequate clearance between the tray and the shell
wall of a distillation column is provided to

A. drain the liquid from the tray when the unit is not
in operation.
B. allow for thermal expansion and facilitate
installation.
C. avoid back-trapping.
D. none of these.

Answer 78

B. allow for thermal expansion and facilitate
installation.

Question 79

Overall tray efficiency of a distillation column is the ratio
of the number of

A. overall gas transfer units to the number of ideal
trays required.
B. ideal trays required to the number of real trays
required.
C. real trays required to the number of ideal trays
required.
D. none of these.

Answer 79

B. ideal trays required to the number of real trays
required.

Question 80

Pick out the wrong statement about the design of a sieve
plate column.

A. An increased weir height improves the tray
efficiency at the cost of high plate pressure drop;
optimum wear height being 40-90 mm for column
pressure above atmospheric and 6-12 mm for
vacuum columns.
B. For segmental downcomers, the chord length is
60-80% of the column diameter. An initial value of
downcomer area of 12% is taken in the design.
C. Width of the calming section provided at the inlet
and outlet sides of the plate is 75 mm for column
diameter below 1.5 metres and 100 mm for larger
diameter columns.
D. Minimum recommended downcomer
residence time for the disengagement of
entrained vapour is the same for both foaming
and non-foaming liquids, which is about 20
seconds.

Answer 80

D. Minimum recommended downcomer
residence time for the disengagement of
entrained vapour is the same for both foaming
and non-foaming liquids, which is about 20
seconds.

Question 81

Generally, no corrosion allowance in wall thickness of a
part is required, if the thickness is more than __________
mm.
A. 10
B. 20
C. 30
D. 5

Answer 81

C. 30

Question 82

Multiple blade paddle agitator is used for mixing high
viscosity liquids/paste in which the paddle diameter is
commonly 0.8 times the tank diameter. However, the
width of the blade is in the range of __________ times the
paddle diameter.

A. 0.1 to 0.25
B. 0.3 to 0.5
C. 0.5 to 0.6
D. 0.65 to 0.80

Answer 82

A. 0.1 to 0.25

Question 83

In a __________ rivetted joint, the rivets in the various
rows are opposite to each other.

A. zig-zag
B. chain
C. diamond
D. none of these

Answer 83

B. chain

Question 84

Pick out the wrong statement:

A. The tensile strength of a brittle material is less
than its compressive strength.
B. The compressive strength of a ductile materia] is
less than its tensile strength.
C. In a thick cylindrical shell, the hoop stress is
maximum at the inner radius.
D. The value of crushing load is more than that
of buckling load for long columns.

Answer 84

D. The value of crushing load is more than that
of buckling load for long columns.

Question 85

Generally, elliptical dished heads

A. are manufactured on 2:1 ratio of major to minor
axis and is recommended to be used for pressure
vessels operating above a pressure of 1.5 MN/m2
B. resist half the pressure rating compared to hemi
spherical head provided on the cylindrical shell of
the same thickness and diameter.
C. are approximately as strong as seamless
cylindrical shell having the corresponding I.D and
O.D.
D. all (a), (b) and (c)

Answer 85

D. all (a), (b) and (c)

Question 86

Pick out the wrong statement pertaining to the
comparative evaluation of performance of the packed
tower and the plate tower.

A. Plate tower is perferred, if interstage cooling is
required to remove heats of reaction or solution.
B. Plate tower is preferred over packed tower, if the
operation involves liquids containing dispersed
solids.
C. The total weight of a dry plate tower is usually
much more than that of a dry packed tower
designed for the same duty.
D. In operations involving large temperature
changes. (e.g. distillation), plate towers are
preferred over packed towers as the packing may
be crushed due to large temperature changes.

Answer 86

C. The total weight of a dry plate tower is usually
much more than that of a dry packed tower
designed for the same duty.

Question 87

The circumferential (hoop) stress in a thin walled
cylinderical vessel under internal pressure is
A. pd/2t
B. pd/4t
C. pd/t
D. pd/3t

Answer 87

A. pd/2t

Question 88

Le/D For fully open gate valves would be

A. much more than that for fully open globe valves.
B. much less (say 2% than that for fully open globe
valves).
C. around 7.
D. both (b) and (c).

Answer 88

D. both (b) and (c).

Question 89

LMTD correction factor is used in heat exchanger design
for
A. double pipe heat exchanger.
B. multipass shell and tube heat exchanger.
C. fouling fluids.
D. counter flow of hot and cold fluids.

Answer 89

B. multipass shell and tube heat exchanger.

Question 90

Floating head heat exchangers are used for the

A. heat transfer between corrosive fluids.
B. cases where temperature difference between
the shell and the tubes is more (>50°C).
C. co-current heat transfer systems.
D. counter-current heat transfer systems.

Answer 90

B. cases where temperature difference between
the shell and the tubes is more (>50°C).

Question 91

The most common standard size of bubble caps used in
industrial operation is

A. 1” dia cap with 0.5” dia riser.
B. 6” dia cap with 4” dia riser.
C. 8” dia cap with 1” dia riser.
D. 4” dia cap with 8” dia riser.

Answer 91

B. 6” dia cap with 4” dia riser.

Question 92

Compensation against openings in process vessels for
giving inlet and outlet connections, for providing sight
glasses and manholes etc. is provided for strength and
rigidity. The most efficient type of compensation is of
__________ type.
A. nozzle or rim
B. flared out
C. fluid in
D. ring plate

Answer 92

A. nozzle or rim

Question 93

In case of a continuous distillation column, increase in
reflux ratio may result in the

A. lower fixed charges for the column.
B. greater cost for the reboiler heat supply.
C. greater cost for the condenser coolant.
D. all (a), (b) and (c).

Answer 93

D. all (a), (b) and (c).

Question 94

In a distillation column, the minimum residence time for
liquid in the downspout is about __________ seconds.
A. 1
B. 8
C. 80
D. 180

Answer 94

B. 8

Question 95

Thickness of the frame of a plate and frame filter as
compared to that of plates is
A. less
B. same
C. more
D. either (a) or (b)

Answer 95

C. more

Question 96

Which of the following factors affect the pressure drop in
a co-current gas-liquid absorption packed tower ?

A. Size, shape, orientation and surface of the
packing particles.
B. Density and viscosity of fluids.
C. Fluid flow rates.
D. All (a), (b) and (c).

Answer 96

D. All (a), (b) and (c).

Question 97

The thickness of heat transfer plates used in the plate type
heat exchanger ranges from __________ mm, pressed in
a single piece provided with grooves & corrugations.

A. 0.3 to 0.8
B. 1.25 to 3.125
C. 3.5 to 7.0
D. 8-12

Answer 97

B. 1.25 to 3.125

Question 98

Rivets are generally specified by the

A. head diameter
B. shank diameter
C. overall length
D. none of these

Answer 98

B. shank diameter

Question 99

Length to diameter ratio of most rotary driers is in the
range of

A. 1 to 2
B. 4 to 10
C. 10 to 20
D. 20 to 30

Answer 99

B. 4 to 10

Question 100

Tube wall thickness depends on the corrosiveness of the
fluids and their operating pressure & temperature and is
specified by Birmingham wire gauge (B.W.G)-a number
which varies from 8 to 18 with the numbers 14 and 16
being more commonly used. Outside diameter of tubes
varies from about 15 to 50 mm; however a tube of less
than __________ mm outside diameter is generally not
recommended for fouling fluids.

A. 16
B. 19
C. 28
D. 38

Answer 100

B. 19

Question 101

Angled baffles are preferred in the agitation tank to control
the swirling action; if the viscosity of the liquid to be mixed
is about 200 poise. However, the baffle may be
completely eliminated for mixing liquids having viscosity
above __________ poise.

A. 300
B. 600
C. 1000
D. 1500

Answer 101

B. 600

Question 102

Ratio of tube length to shell diameter for a shell and tube
heat exchanger is

A. 8 : 1 to 12 : 1 for both liquid-liquid and gas-gas
heat exchangers.
B. 4 : 1 to 8 : 1 for liquid-liquid exchanger.
C. < 4 : 1 for gas-gas exchangers.
D. both(b) & (c).

Answer 102

D. both(b) & (c)

Question 103

The dust collection efficiency of a cyclone separator

A. decreases with increase in gas flow rate.
B. is inversely proportional to the mass of the dust
particle.
C. is directly proportional to the radius of the dust
particle path.
D. none of these.

Answer 103

D. none of these.

Question 104

In a shell and tube heat exchanger, the overall heat
transfer co-efficient is proportional to the tube side
(volumetric flow rate)0.8. This is valid, only when the ratio
of the tube side film resistance to the total resistance is
almost equal to

A. ∞
B. 1
C. 20.8
D. 2

Answer 104

B. 1

Question 105

Which of the following types of reactors is the safest from
operation point of view?

A. A vapor phase reactor.
B. Pot type reactor.
C. A liquid phase reactor.
D. A liquid phase catalytic reactor.

Answer 105

A. A vapor phase reactor.

Question 106

In a bag filter, the pressure drop increases directly as the

A. density of the gas, but is independent of the
viscosity of the gas.
B. density of the gas and inversely as viscosity
of the gas.
C. viscosity of the gas and inversely as density of the
gas.
D. none of these.

Answer 106

B. density of the gas and inversely as viscosity
of the gas.

Question 107

The LMTD correction factor (FT) is applied in __________
heat exchangers.

A. 1-1 cocurrent
B. double pipe
C. all multipass
D. all (involving liquid/liquid heat transfer)

Answer 107

C. all multipass

Question 108

Movement of pipeline caused by thermal expansion is
taken care by providing

A. expansion joint.
B. changes in its direction.
C. change in the shape of pipeline.
D. all (a), (b) and (c).

Answer 108

D. all (a), (b) and (c).

Question 109

For a cylindrical shell, (subject to the thickness of
uppermost course being more than the minimum for
diaofthe tank in question), the thickness of the courses of
shell

A. decreases upwards.
B. increases upwards.
C. remains same throughout.
D. may decrease or increase upwards depending
upon whether vacuum or positive pressure would
be maintained inside the shell.

Answer 109

A. decreases upwards

Question 110

In the design of a paddle agitator, the ratio of paddle
diameter over tank diameter is normally taken as
A. 0.1
B. 0.8
C. 0.25
D. 0.5

Answer 110

B. 0.8

Question 111

The design stress, which is more than the damaging
stress, is the least unit stress that will render a member
unfit for service before the end of its normal life. The
design stress factor or factor of safety indicates the
margin between design stress and the __________
stress.

A. working
B. damaging
C. allowable
D. none of these

Answer 111

B. damaging

Question 112

Hole diameter of the seive trays in the distillation column
ranges from __________ mm.

A. l to3
B. 4 to 8
C. 3 to 12.5
D. 12.5 to 18.5

Answer 112

C. 3 to 12.5

Question 113

Factor of safety (i.e., overdesign factor) in heat transfer
equipments is about __________ percent more than the
actual/theoretical design factor.

A. 5-10
B. 15-20
C. 30-35
D. 35-40

Answer 113

B. 15-20

Question 114

For annular flow of a fluid, the ratio of the equivalent
diameter for pressure drop calculation to the equivalent
diameter for heat transfer calculation is

A. d1/(d1+d2)
B. d2(d1+d2)
C. (d2+d1)/d1
D. (d2+d1)/d2

Answer 114

A. d1/(d1+d2)

Question 115

In actual operation of distillation column, the vapour is not
distributed uniformly among the bubble caps, primarily
because of the

A. liquid gradient on the tray.
B. lower skirt clearance.
C. lower static submergence.
D. small downcomer liquid seal.

Answer 115

A. liquid gradient on the tray.

Question 116

The minimum shell thickness for tank ≤ 15 metres
diameter is limited to __________ mm, for reasons of
elastic stability.

A. 2
B. 5
C. 10
D. 15

Answer 116

B. 5

Question 117

If ‘D’ is the inside diameter of the shell of a shell and tube
heat exchanger, then the baffle spacing is usually in the
range of

A. D/2 or minimum 2” to 5D.
B. D/5 or minimum 2” to 5D.
C. D/5 or minimum 2” to D.
D. none of these.

Answer 117

B. D/5 or minimum 2” to 5D.

Question 118

Brass valves are usually made for pipe sizes __________
inches.

A. ≤1
B. ≤2
C. >2.5
D. >3.5

Answer 118

B. ≤2

Question 119

At the following point for a given packing and set of fluids,
the pressure drop per metre of packed height, with
variation in fluid rates and operating pressure

A. increases
B. decreases
C. remains same
D. may increase or decrease depending upon the
solubility of the gas in the liquid

Answer 119

C. remains same

Question 120

In a shell and tube heat exchanger, triangular pitch
arrangement as compared to square pitch arrangement

A. results in higher shell side pressure drop.
B. can accommodate less number of tubes for a given
shell diameter.
C. facilitates easier shell side cleaning; hence is more suitable for handling high dirt factor shell
side fluid.
D. creates relatively lower turbulence on the shell side resulting in lower shell side heat transfer co-
efficient.

Answer 120

A. results in higher shell side pressure drop

Question 121

Pick out the wrong statement about routing of fluids in a
shell and tube heat exchanger.

A. The corrosive and fouling fluid should be
preferably routed through the tubes.
B. The viscous fluid should be routed through the
shell side.
C. Lower flow rate fluid should be routed through the
shell side.
D. Higher pressure fluid stream should be routed
through the shell side.

Answer 121

D. Higher pressure fluid stream should be routed
through the shell side.

Question 122

The necessary wall thickness for a metallic storage vessel
is a function of the

A. ultimate tensile strength (or yield point) of the
material and operating temperature.
B. operating pressure and welding/joint efficiency.
C. diameter of the vessel.
D. all (a); (b) and (c).

Answer 122

D. all (a); (b) and (c).

Question 123

In a multiple effect evaporator system having ‘n’ effects,
the amount of water evaporated per unit surface area in
approximately equal to __________ times that in a single
effect.

A. ‘n’th
B. (1/n)th
C. 0.5 nth
D. 1.5 nth

Answer 123

B. (1/n)th

Question 124

Pick out the wrong statement

A. In a flanged and standard dished head, the crown
radius is ≤ shell outside diameter.
B. In a flanged and shallow dished head, the crown
radius is > shell outside diameter.
C. Flat head covers are most suitable for larger
vessels operating at very high pressure.
D. Flanged only head is a type of flat head in which
gradual change in the shape at the centre results
in reduced local stresses.

Answer 124

C. Flat head covers are most suitable for larger
vessels operating at very high pressure.

Question 125

Pick out the wrong statement pertaining to the design of a
horizontal tube evaporator.

A. It is unsuitable for concentrating those liquids,
which form a scale or deposit salt.
B. It is suitable for process, in which the final product
is a liquor instead of solid.
C. Its usual dimensions are: tube dia = 2-3 cms;
evaporator body dia = 1-4 metres and evaporator
height = 2.5-4 metres.
D. Liquor flows inside the tube, while the steam
is outside submerging the tube.

Answer 125

D. Liquor flows inside the tube, while the steam
is outside submerging the tube.

Question 126

Weep holes provided in the plates of a distillation column
A. facilitate draining out liquid from a tray when the
unit is not in operation.
B. are normally located near the overflow weir so
that any delivery of liquid during operation follows
approximately the same path as the overflow
fluid.
C. must be large enough (usually 1/4” to 5/8” dia) to
prevent plugging but should not deliver excessive
amount of fluid during operation.
D. all (a), (b) and (c).

Answer 126

D. all (a), (b) and (c).

Question 127

Steam is preferred to be used as a heating medium in
heat exchangers, because of its

A. low cost.
B. high latent heat.
C. non-corrosive condensate.
D. high film co-efficient.

Answer 127

B. high latent heat.

Question 128

__________ shapedroof is the most commonly used roof
for cylinderical storage tanks.

A. Conical
B. Flat
C. Dome
D. Umbrella

Answer 128

A. Conical

Question 129

Pick out the wrong statement pertaining to ‘Horton sphere’
used for the storage of liquid ammonia.

A. Diameter of Horton sphere is normally 6 to 25
metres and it is supported by 6 to 12 nos. tubular
or rolled section column.
B. Thickness of spherical shell is half that of the
cylinderical vessel under same operating
pressure condition. Besides, the ratio of surface
area to volume is less for sphere than any other
shape ; hence insulation required is less.
C. Horton sphere is used for the storage of gases
and volatile liquid at a moderate pressure of 1 to
10 kg/cm2 .
D. Horton sphere is used for the storage of liquid
at sub-zero temperature at very high pressure
upto 200 kg/cm2 .

Answer 129

D. Horton sphere is used for the storage of liquid
at sub-zero temperature at very high pressure
upto 200 kg/cm2

Question 130

Value of Peclet number = ∞, is the representative of
A. laminar flow.
B. complete back mixing,
C. plug flow.
D. eddy diffusivity = 0.

Answer 130

C. plug flow.

Question 131

Le/D for a Tee (used as elbow, entering branch) would be

A. less than that for Tee (used as elbow, entering
run).
B. more than that for Tee (used as elbow, entering
run).
C. around 90.
D. both (b) and (c).

Answer 131

D. both (b) and (c).

Question 132

In most of the shell and tube heat exchangers, the tube
pitch is generally __________ the tube diameter.

A. less than
B. 1.25-1.50 times
C. 2.5 times
D. one-fourth of

Answer 132

B. 1.25-1.50 times

Question 133

In a distillation column, bubble caps are located on trays
with a pitch of __________ times the outside diameter of
the caps.

A. 1.3 to 2
B. 1.6 to 2
C. 2.5
D. 1.5 to 3

Answer 133

A. 1.3 to 2

Question 134

1.2 to 3.8 cms is the value of the

A. downcomer liquid seal in case of a balanced tray
design.
B. static submergence in case of a bubble cap tray
for column operating under pressure (≥ 1 atm.).
C. skirt clearance for bubble caps.
D. all (a), (b) and (c).

Answer 134

D. all (a), (b) and (c).

Question 135

Accidents in chemical plants are mostly due to
A. inadequate equipment design.
B. faulty operating procedures.
C. improper layout of the equipment
D. failure of equipment

Answer 135

B. faulty operating procedures.

Question 136

For identical operating conditions, the pressure drop over
__________ tray is the highest out of the following.
A. sieve
B. valve
C. counterflow
D. bubble cap

Answer 136

D. bubble cap

Question 137

A perforated plate has holes of diameter dn arranged in a
pitch ph. Each hole has a tube of I.D. dt passing through
it. The ligament efficiency is given by

A. (ph - dh)/ph
B. (ph - dh . dt/2)/ph
C. (ph - dt)/ph
D. (ph - dh)/dh

Answer 137

C. (ph - dt)/ph

Question 138

__________ is the determining factor for the number of
bubble caps to be used per tray.
A. Permissible slot velocity
B. Tray diameter
C. Liquid load
D. Vapor load

Answer 138

A. Permissible slot velocity

Question 139

Pick out the wrong statement about distillation operation

A. Distillation under vacuum is a substitute for steam
distillation.
B. In differential (simple) distillation, the vapour is
removed as soon as it is formed without
appreciable condensation.
C. In flash (equilibrium) distillation, a definite fraction
of liquid is vaporised in such a way that the
evolved vapour & residual liquids are in
equilibrium with each other.
D. Flash distillation, differential distillation &
steam distillation are all continuous
distillation processes.

Answer 139

D. Flash distillation, differential distillation &
steam distillation are all continuous
distillation processes

Question 140

Low pressure steam (with saturation temperature
between 105 to 120°C) is usually used in the vacuum
evaporators, which normally employ a vacuum of about
__________ mm Hg (referred to a 760 mm mercury
barometer).

A. 250
B. 450
C. 650
D. 750

Answer 140

C. 650

Question 141

Which of the following is the best tube material from
thermal conductivity point of view alone?

A. Aluminium
B. Stainless steel
C. Copper
D. Carbon steel

Answer 141

C. Copper

Question 142

Normal screwed fittings are used for pipes upto a
diameter of __________ inches.
A. 1.5
B. 3
C. 5
D. 7

Answer 142

B. 3

Question 143

In a shell and tube heat exchanger, the clearance of the
tube is generally

A. not less than one-fourth of the tube diameter
or 3/16”.
B. more than the tube diameter.
C. equal to the tube diameter.
D. more in case of triangular pitch as compared to
the square pitch tube layout.

Answer 143

A. not less than one-fourth of the tube diameter
or 3/16”.

Question 144

Diameter of the seive tray column is determined by the

A. lower limit of vapour velocity.
B. upper limit of the vapour velocity.
C. hole diameter of the seive tray.
D. height of the plate spacing.

Answer 144

B. upper limit of the vapour velocity.

Question 145

For a given fluid, as the pipe diameter increases, the
pumping cost

A. decreases.
B. increases.
C. remains unaffected.
D. may increase or decreaes depending upon
whether the fluid is Newtonian or non-Newtonion.

Answer 145

A. decreases.

Question 146

Maximum acceptable total liquid gradient over a tray is
about __________ mm.

A. 5.5
B. 12.5
C. 30.5
D. 45.5

Answer 146

B. 12.5

Question 147

In case of a ‘thin’ pressure vessel, the ratio of its diameter
to wall thickness is

A. < 10
B. > 10
C. > 20
D. 30

Answer 147

B. > 10

Question 148

High pressure fluid in a shell and tube heat exchanger
should preferably be routed through the

A. tubes to avoid the expansion of high pressure
shell construction.
B. shell side for smaller total pressure drop.
C. shell side, if the flow is counter-current and tube
side if the flow is co-current.

D. shell side for large overall heat transfer co-
efficient.

Answer 148

A. tubes to avoid the expansion of high pressure
shell construction

Question 149

Bubble cap tray is the most commonly used tray in large
distillation column, because
A. of its flexibility and nearly constant efficiency
under varying conditions of operation.
A. of its flexibility and nearly constant efficiency
under varying conditions of operation.
B. it incurs less pressure drop as compared to any
other try designed for the same duty.
C. it eliminates the foaming and entrain-ment
tendency during operation.
D. none of these.

Answer 149

A. of its flexibility and nearly constant efficiency
under varying conditions of operation.

Question 150

In common bubble cap distillation column design practice,
riser area is approximately equal to (where, Aa = Annular
passage area, and Sa = Slot area)
A. Aa = Sa
B. 1.2 Aa = 1.2 Sa
C. Sa = 1.5 Aa
D. Aa = 1.5 Sa

Answer 150

A. Aa = Sa

Question 151

Heat transfer co-efficient, hG(Kcal/hr.m2 .°C) and mass
velocity of air, G (kg/hr.m2 ) for air flow parallel to the
surface in case of constant drying rate in batch drying is
related as hG = 0.0176G0.8. But when the flow of air
perpendicular to the surface is encountered, this equation
changes to
A. hG = 1.004G0.37
B. 1.004G0.8
C. hG = 0.0176G0.37
D. 0.0176G1.37

Answer 151

A. hG = 1.004G0.37

Question 152

In the agitators, the power required will be changed with
the increase of diameter of agitator (D) as
A. D2
B. D5
C. D
D. D9

Answer 152

B. D5

Question 153

Rate of filtrate delivery is inversely proportional to the
A. filtering area & the pressure difference driving
force.
B. viscosity of filtrate.
C. cake & filter medium resistance.
D. both (a) and (b)

Answer 153

D. both (a) and (b)

Question 154

Tube side heat transfer co-efficient for turbulent flow of
liquid through tubes is proportional to
A. G^0.2
B. G^0.5
C. G^0.8
D. G^1.5

Answer 154

C. G^0.8

Question 155

Circumferential (hoop) stress in a thin cylindrical vessel
under internal pressure is __________ the longitudinal
stress.

A. half
B. equal to
C. twice
D. eight times

Answer 155

C. twice

Question 156

The dust collection efficiency of electrostatic precipitator
increases with increase in the
A. gas flow rate.
B. electrode area.
C. both (a) & (b).
D. neither (a) nor (b).

Answer 156

B. electrode area.

Question 157

For storing hazardous chemicals in large storage tanks,
the minimum safe distance between the two tanks should
range between __________ times the tank diameter.
A. 1 to 1.5
B. 2.5 to 3.5
C. 4 to 5
D. 6 to 8

Answer 157

A. 1 to 1.5

Question 158

Which of the following factors determine the amount of
entrainment in a distillation column ?
A. Plate spacing.
B. Depth of liquid above the bubble cap slots.
C. Vapour velocity in the volume between the plates.
D. All (a), (b) and (c).

Answer 158

D. All (a), (b) and (c).

Question 159

The absorption factor is defined as (where, S1 = slope of
the equilibrium curve, S2 = slope of the operating line)
A. S1/S2
B. S1.S2
C. S2/S1
D. 1/S1.S2

Answer 159

A. S1/S2

Question 160

In shell and tube heat exchangers, straight tie rods are
used to
A. hold baffle in space.
B. fix the tubes in position.
C. account for thermal strain.
D. none of these.

Answer 160

A. hold baffle in space

Question 161

In case of design of a shell and tube heat exchanger,
A. minimum cleaning lane of 6.5 mm is provided,
when tubes are on a square pitch.
B. minimum tube sheet thickness (in which tubes are
fixed) is equal to the O.D. of the tube upto 15 mm
tube diameter; and for > 15 mm tube diameter,
tube sheet thickness is smaller than tube
diameter.
C. O.D. of the tube is 6 to 40 mm while the tube
lengths used are 0.5, 2.5, 3.0, 4.0, 5.0, 6 metres.
D. all (a), (b) & (c).

Answer 161

D. all (a), (b) & (c).

Question 162

In a cylinderical vessel subjected to internal pressure, the
longitudinal stress σL and the circumferential stress, σn
are related by
A. σh = 2 σL
B. σh = σL
C. σh = σL/2
D. no relation exists

Answer 162

A. σh = 2 σL

Question 163

Excessive liquid gradient on a tray may result in the
A. maldistribution of gas.
B. back trapping.
C. gas blowing beneath cap skit.
D. all (a), (b) and (c).

Answer 163

D. all (a), (b) and (c).

Question 164

The ratio of tube length to shell diameter in case of liquid
shell and tube heat exchanger ranges from
A. 2 to 3
B. 3 to 5
C. 4 to 8
D. 6 to 12

Answer 164

C. 4 to 8

Question 165

What is the slope of the operating line in the stripping
section of a distillation column ?
A. 0
B. ∞
C. > 1
D. < 1

Answer 165

C. > 1

Question 166

__________ shaped roof is most commonly used for
cylindrical tanks.
A. Cone
B. Dome
C. Umbrella
D. Flat

Answer 166

A. Cone

Question 167

In a thin cylindrical shell, the hoop stress is __________
stress.
A. radial
B.circumferential tensile
C. compressive

Answer 167

B.circumferential tensile

Question 168

Commercial packed scrubbers are normally designed for
a pressure drop range of __________ mm water coloumn
per metre of packed height.
A. 4-8
B. 17-34
C. 52-68
D. 88-105

Answer 168

B. 17-34

Question 169

The retention time of material in a rotary dryer depends
upon its
A. rpm
B. slope & length
C. flights arrangement
D. all (a), (b) and (c)

Answer 169

D. all (a), (b) and (c)

Question 170

In actual operation of a bubble cap distillation tower, the
__________ at the bottom of the tower is more than that
at the top of the tower.
A. molal flow rate of vapour
B. vapour molecular weight
C. pressure and temperature
D. all (a), (b) and (c)

Answer 170

D. all (a), (b) and (c)

Question 171

Rotary driers are most economically designed for the
number of heat transfer units (HTU) from
A. 0.01 to 1
B. 1.5 to 2.5
C. 5 to 10
D. 10 to 20

Answer 171

B. 1.5 to 2.5

Question 172

The difficulty of liquid distribution in packed towers is
accentuated, when the ratio of tower diameter to packing
diameter is
A. < 30
B. < 7
C. > 7 < 15
D. > 20 < 50

Answer 172

B. < 7

Question 173

A forced circulation long tube vertical evaporator as
compared to the natural circulation evaporator
A. is economical in operation.
B. employs high velocity, high heat transfer rate and
less heating surface requirement.
C. employs a centrifugal pump placed between
external downtake from vapor drum and inlet to
tube bundle.
D. both (b) & (c).

Answer 173

D. both (b) & (c).

Question 174

An increase in the liquid resistance to interphase mass
transfer and a resultant reduction in plate efficiency is
caused by
A. an increase in liquid viscosity.
B. an increase in relatived volatility for rectification
columns.
C. decrease in gas solubility for absorbers.
D. all (a), (b) and (c).

Answer 174

D. all (a), (b) and (c).

Question 175

In the design of a bag filter, the gas temperature is an
important consideration, as it affects the
A. gas density
B. gas viscosity
C. fibre selection
D. all (a), (b) & (c)

Answer 175

D. all (a), (b) & (c)

Question 176

With increase in temperature drop (in a shell and tube
heat exchanger), the LMTD correction factor, FT
A. decreases very rapidly
B. increases very rapidly
C. remains constant
D. increases linearly

Answer 176

A. decreases very rapidly

Question 177

The normal range of velocity of steam in pipes is
__________ m/sec.
A. 0.1-0.5
B. 1-5
C. 10-20
D. 80-100

Answer 177

D. 80-100

Question 178

__________ dished head is the strongest of all.
A. Hemispherical
B. Elliptical
C. Torispherical
D. none of these

Answer 178

A. Hemispherical

Question 179

Pick out the correct statement.

A. It is preferred to use a vertical condenser for
condensation of vapor from a distillation column
without sub-cooling
B. Draining of residual liquid on tray during shut
down of distillation column is facilitated by weep
holes.
C. Random packing a packed tower offers the
advantage of lower pressure drop and higher
throughput of fluids as compared to
regular/stacked packing.
D. Risers are generally not connected to the
plate in a distillation coloumn by bolts, rivets
or welding.

Answer 179

D. Risers are generally not connected to the
plate in a distillation coloumn by bolts, rivets
or welding.

Question 180

“A clamming section” before the liquid flows into the
downcomer is provided to
A. permit release of entrained vapour in the
liquid.
B. reduce the discharge fluctuation.
C. ensure better vapour-liquid contact.
D. cool the liquid before it flows down.

Answer 180

A. permit release of entrained vapour in the
liquid.

Question 181

The units of Young’s modulus of elasticity and
__________ are the same.
A. strain
B. stress
C. modular ratio
D. none of these

Answer 181

B. stress

Question 182

In the design of a shell and tube heat exchanger, the
corrosion allowance
A. need not be provided for non-pressure parts like
tie rods, spacers, baffles, supports etc.
B. for carbon steel and cast iron pressure parts is 1.5
mm (except for tubes) and for severe conditions it
is 3 mm.
C. for internal cover and tube sheet is provided on
both the sides.
D. all (a), (b) & (c).

Answer 182

D. all (a), (b) & (c).

Question 183

Vertical condenser is advantageous to the horizontal
condenser from operation point of view, when
A. hydrostatic head is required for refluxing the
condensate.
B. only the function of condensation is to be carried
out.
C. sub cooling of condensate is desired.
D. both the functions of condensation & sub
cooling are carried out in a single unit.

Answer 183

D. both the functions of condensation & sub
cooling are carried out in a single unit.

Question 184

Hazards associated with the relief valve leakage for
extremely hazardous material storage can be taken care
of by providing
A. rupture diaphragm
B. dikes
C. surge chamber
D. none of these

Answer 184

A. rupture diaphragm

Question 185

Minimum baffle spacing recommended in a shell and tube
heat exchanger is equal to
A. 5 cms
B. 40% of the I.D. of the shell
C. 25 cms
D. I.D. of the shell

Answer 185

A. 5 cms

Question 186

__________ liquor is best handled in a long tube vertical
evaporator.
A. Foamy
B. Scaling
C. Viscous
D. Salting

Answer 186

A. Foamy

Question 187

Theoretically calculated diameter of the stripping section
of the continuous rectification column is __________ that
of the enriching section.
A. less than
B. more than
C. same as
D. either more or less (depending upon relative
volatility)

Answer 187

B. more than

Question 188

Hold up of material in an operating rotary drier is in the
range of
A. 0.05 to 0.15
B. 0.25 to 0.50
C. 0.5 to 0.8
D. 0.8 to 0.9

Answer 188

A. 0.05 to 0.15

Question 189

A binary liquid azeotropic mixture has boiling point higher
than either of the components, when it shows
__________ deviation from Raoult’s Law.
A. positive
B. negative
C. no
D. none of these

Answer 189

B. negative

Question 190

Flanges are connected to pipes by
A. screwing
B. welding
C. brazing
D. all (a), (b) and (c)

Answer 190

D. all (a), (b) and (c)

Question 191

The ratio of down take area to cross-sectional area of the
tube, for calendria type evaporator ranges from
A. 0.5 to 1
B. 1 to 1.5
C. 1.5 to 2
D. 2 to 2.5

Answer 191

A. 0.5 to 1

Question 192

Shortest distance between two tubes is
A. called tube pitch.
B. called tube clearance.
C. more in case of triangular pitch as compared to
square pitch of tube layout.
D. none of these.

Answer 192

B. called tube clearance.

Question 193

__________ tower is the most suitable gas-liquid
contacting device involving highly corrosive fluids.
A. Sieve plate
B. Packed
C. Bubble cap plate
D. None of these

Answer 193

B. Packed

Question 194

At equal mass velocities, the values of film coefficients for
gases as compared to that for liquids are generally.
A. higher
B. lower
C. same
D. unpredictable

Answer 194

B. lower

Question 195

The ratio of the largest load in a test to the original cross-
sectional area of the test specimen is called the

__________ stress.
A. yield point
B. breaking
C. ultimate
D. none of these

Answer 195

C. ultimate

Question 196

Baffle spacing is generally __________ the I.D. of the
shell.
A. more than
B. not greater than
C. not less than one fifth of
D. both (b) and (c)

Answer 196

D. both (b) and (c)

Question 197

The wall thickness of thin cylindrical shell with
hemispherical ends is __________ that of the spherical
ends.
A. equal to
B. more than
C. less than
D. either (b) or (c); depends on maximum
permissible internal pressure

Answer 197

B. more than

Question 198

A ‘rupture disc’ is provided in chemical equipments as an
accessory meant for

A. relieving excess pressure.
B. creating turbulence.
C. enhancing mixing rate.
D. avoiding vortex formation.

Answer 198

A. relieving excess pressure

Question 199

In a vertical short tube evaporator (Calendria type), the
A. tube dia of 2.5-7.5 cms, tube length of 75-200 cms
and cylinderical drum dia of 1-6 metres are
normally used.
B. area of central downtake is equal to 40 to 100%
of total cross-sectional area of the surrounding
tube.
C. liquor is inside the tube while the steam is outside
the tube.
D. all (a), (b) & (c).

Answer 199

D. all (a), (b) & (c)

Question 200

In a multipass shell and tube heat exchanger, the problem
of differential expansion between the shell and tube
passes is taken care of by using a
A. U-bend
B. floating head tube sheet
C. either (a) or (b)
D. neither (a) nor (b)

Answer 200

C. either (a) or (b)

Question 201

In a shell and tube heat exchanger, the shortest centre to
centre distance between the adjacent tubes is
A. called tube pitch.
B. called tube clearance.
In a shell and tube heat exchanger, the shortest centre to
centre distance between the adjacent tubes is
A. called tube pitch.
B. called tube clearance.
C. always less than the diameter of the tube.
D. none of these.

Answer 201

A. called tube pitch.

Question 202

Any shell opening greater than 5 cms for a storage tank
must be reinforced for reason of
A. preventing the local overstressing of the shell
around the opening.
B. reduction of discontinuity in shape at the junction.
C. making the joint leak proof.
D. none of these.

Answer 202

A. preventing the local overstressing of the shell
around the opening.

Question 203

Minimum tube pitch recommended for shell and tube heat
exchangers is about __________ times the outside
diameter of the tube.
A. 1.25
B. 1.75
C. 2.5
D. 3.5

Answer 203

A. 1.25

Question 204

Liquid redistribution should be done in a packed tower
packed with raschig rings every 6 metres or __________
times the column diameter, whichever is lower.
A. 2.5-3.0
B. 5-7.5
C. 10-12.5
D. 15-20

Answer 204

A. 2.5-3.0

Question 205

Slope of countercurrent flow rotary drier is in the range of
__________ meter/metre.
A. 0 to 0.08
B. 0 to 0.8
C. 0 to 1.5
D. 0 to 2.2

Answer 205

A. 0 to 0.08

Question 206

In case of saddle packing (e.g., berl and intralox saddles),
the maximum size of the packing should not exceed
__________ of the column diameter.
A. l/5th
B. l/15th
C. l/30th
D. l/50th

Answer 206

B. l/15th

Question 207

Seamless pipe is made

A. from rolled strips formed into cylinders and seam-
welded.

B. by extrusion & casting into static and centrifugal
molds.
C. by forging a solid round, piercing it by
simultaneously rotating & forcing it over a piercer
point and further reducing it by rolling gas
drawing.
D. both (b) and (c).

Answer 207

D. both (b) and (c).

Question 208

The thermal stress in a metallic bar does not depend upon
the
A. changes in temperature.
B. cross-sectional area.
C. both (a) and (b).
D. neither (a) nor (b).

Answer 208

B. cross-sectional area.

Question 209

The minimum baffle height should be
A. equal to the impeller diameter.
B. twice the impeller diameter.
C. twice the tank diameter.
D. 3/4 of the tank height.

Answer 209

B. twice the impeller diameter

Question 210

For turbulent flow (NRe > 2100) of low viscosity fluid (μ >
20cp) in steel pipes, the optimum inside pipe diameter is
given by(where, Q = fluid flow rate, ft3/sec.ρ = fluid
density, lb/ft3 μ = fluid viscosity, centipoise Di = optimum
inside pipe diameter, inches)
A. Di, opt = 3.9 Q0.45 ρ0.13
B. Di, opt = 3.9 Q0.45 . μ0.95
C. Di, opt = 4.7 Q0.36 . μ3.2ρ0.13
D. Di, opt = 3 Q0.36 . μ0.88

Answer 210

A. Di, opt = 3.9 Q0.45 ρ0.13

Question 211

To avoid the tearing off the plate of an edge, the margin
(i.e., the minimum distance from the centre of the rivet
hole to the nearest edge of the plate) should be equal to
A. 0.5 d
B. d
C. 1.5 d
D. 2.5 d

Answer 211

C. 1.5 d

Question 212

The normal range of velocity of water in pipes is
__________ m/sec.
A. 0.1-0.5
B. 1-2
C. 10-50
D. 15-30

Answer 212

B. 1-2

Question 213

Baffles are provided in a shell and tube heat exchanger to
increase the turbulence and velocity of the shell side fluid.
Which of the following shaped baffles does not fall in the
category of transverse baffle ?
A. Segmental baffle
B. Flat plate extending across the wall
C. Disk type baffle
D. Helical type baffle

Answer 213

B. Flat plate extending across the wall

Question 214

A certain pressure vessel manufacturer avoids doing
reinforcements calculations for openings by always
providing a reinforcing pad extending upto double the
diameter of the opening and of the same material and
thickness as that of the shell wall. If area compensation is
accepted as a code guideline, his approach leads to safe
design
A. only if the opening is on spherical vessel.
B. only if the opening is on a vertical cylinderical
vessel.
C. only if the opening is on a horizontal cylinderical
vessel.
D. irrespective of the shape of the vessel.

Answer 214

D. irrespective of the shape of the vessel.

Question 215

In a __________ rivetted joint, the number of rivets
decreases from the innermost row to the outermost row.
A. chain
B. diamond
C. zig-zag
D. none of these

Answer 215

B. diamond

Question 216

Large process vessels operating under extreme
temperature and pressure conditions are normally clad/
lined with materials like stainless steel, aluminium, nickel
& its alloys, copper & its alloys and titanium. The cladding
thickness is generally about __________ percent of the
total thickness.
A. 1 to 5
B. 10 to 20
C. 30 to 40
D. 40 to 50

Answer 216

B. 10 to 20

Question 217

Heat transfer co-efficient for a horizontal condenser as
compared to a vertical condenser operating under similar
conditions is
A. same
B. less
C. about 3 times
D. about 0.33 times

Answer 217

C. about 3 times

Question 218

Pick out the wrong statement pertaining to the design of
the distillation column.
A. Generally, a skirt clerance of 0.5” to 1.5’ is
recommended to prevent plugging of the slots by
residue build up.
B. The purpose of the slot is to disperse the gas into
the liquid in the form of small bubbles.
C. If sufficient slot area is not provided, the gas may
pass through the skirt clearance.
D. none of these.

Answer 218

D. none of these.

Question 219

In distillation columns, bubble caps are held in place over
trays by
A. rivets
B. a hold down bar
C. bolts
D. both (b) and (c)

Answer 219

D. both (b) and (c)

Question 220

The buckling tendency of compression members is
always in the direction of the
A. least radius of gyration.
B. axis of the load.
C. perpendicular to the axis of the load.
D. none of these.

Answer 220

A. least radius of gyration.

Question 221

In case of plain carbon steel, butt welded joints are used
for shell plate thickness ≤ __________ cms.
A. 1.2
B. 0.5
C. 3.8
D. 6.8

Answer 221

C. 3.8

Question 222

The average velocity in the tubes of a 1-4 heat exchanger
is __________ times that in 1-1 heat exchanger having
the same size & number of tubes and operated at same
liquid flow rate.
A. 2
B. 1/2
C. 4
D. 1/4

Answer 222

C. 4

Question 223

When one of the fluids is highly corrosive and has fouling
tendency, it should

A. preferably flow inside the tube for its easier
internal cleaning.
B. perferably flow outside the tube.
C. flow at a very slow velocity.
D. flow outside the tube, when the flow is counter-
current and inside the tube when the flow is co-
current.

Answer 223

A. preferably flow inside the tube for its easier
internal cleaning.

Question 224

A/an __________ is used for changing the direction of a
pipeline.
A. elbow
B. union
C. flange
D. disc compensator

Answer 224

A. elbow

Question 225

Maximum plate efficiency is achieved in case of
__________ flow.
A. split
B. cross
C. cascade
D. reverse

Answer 225

B. cross

Question 226

The LMTD correction factor (FT) is defined as the
A. ratio of true temperature difference to the
LMTD.
B. ratio of LMTD to the true temperature difference.
C. differenced of true temperature difference and the
LMTD.
D. geometric mean of the true temperature
difference and the LMTD.

Answer 226

A. ratio of true temperature difference to the
LMTD.

Question 227

The clearance between two tubes in a shell and tube heat
exchanger is known as ‘ligament’, whose minimum value
is __________ the outside diameter of the tube, but in no
case it should be less than 4.5 mm.
A. equal to
B. half
C. one fourth
D. three fourth

Answer 227

C. one fourth

Question 228

The ratio for the rate of washing to the final rate of filtration
in a washing type of plate and frame filter is
A. 0.25
B. 0.50
C. 0.75
D. 1.25

Answer 228

A. 0.25

Question 229

Normally, the length to diameter ratio of rotary dryers
varies form 4 to 10 and for its economic operation, the
number of transfer units (NTU) for such dryers varies from
A. 1.5-2.5
B. 3.5-5.5
C. 7.5-10.0
D. 10-15

Answer 229

A. 1.5-2.5

Question 230

Value of Peclet number = 0, is the representative of
A. laminar flow.
B. complete back mixing.
C. plug flow.
D. eddy diffusivity = 0.

Answer 230

B. complete back mixing.

Question 231

Poisson’s ratio of a material is the ratio of unit lateral strain
to the unit axial elongation within its elastic limit. The value
of Poisson’s ratio for structural and pressure vessel steel
may be taken as
A. 0.01
B. 0.3
C. 0.75
D. 0.95

Answer 231

B. 0.3

Question 232

Removable connection of tubes to tube sheet is called
A. ferrule
B. socket
C. nipple
D. saddle

Answer 232

A. ferrule

Question 233

Typical static submergence for bubble cap plate column
operating at atmospheric pressure may be around
A. 2.5”
B. 0.5”
C. 5”
D. 50% of the plate spacing

Answer 233

B. 0.5”

Question 234

In the allocated cap area, bubble caps are generally
arranged on equilateral triangular pitch. Number of caps
fixed on a plate is with a
A. clearance of 25-75 mm.
B. cap pitch of 1.3-2 times the cap diameter.
C. either ‘a’ or ‘b’.
D. neither ‘a’ nor ‘b’.

Answer 234

C. either ‘a’ or ‘b’

Question 235

The length of straight rectangular weir used on cross-flow
trays is generally __________ the column diameter.
A. 0.6-0.8 times
B. equal to
C. twice
D. 2 ft irrespective of (for column > 3 ft diameter)

Answer 235

A. 0.6-0.8 times

Question 236

Le/D for couplings and unions would be
A. 60
B. 200
C. 350
D. negligible

Answer 236

D. negligible

Question 237

What is the slope of the operating line in the rectifying
section of a distillation coloumn ?
A. 0
B. ∞
C. > 1
D. <1

Answer 237

D. <1

Question 238

Stage efficiency for packed tower varies with the
A. type & size of packing.
B. fluid rates and fluid properties.
C. operating pressure and column diameter.
D. all (a), (b) and (c).

Answer 238

D. all (a), (b) and (c).

Question 239

The minimum plate spacing in most of the pertroleum
refinery distillation columns (of dia > 3 ft) is normally
__________ inches.
A. 6
B. 12
C. 18
D. 34

Answer 239

C. 18

Question 240

Joint efficiency (J) for a seamless pipe is
A. 1
B. 0.85
C. 1.2
D. < 0.5

Answer 240

A. 1

Question 241

For a given design of bubble cap, the number of bubble
caps to be used per tray is set by the
A. allowable gas velocity through the slots.
B. plate spacing.
C. diameter of the column.
D. all (a), (b) and (c).

Answer 241

A. allowable gas velocity through the slots

Question 242

The shell side pressure drop in a shell and tube heat
exchanger is maximum for __________ baffle.
A. disk and ring
B. segmental
C. orifice
D. independent of the type of

Answer 242

C. orifice

Question 243

The function of manholes provided in the shell of a
distillation column is to
A. keep a check on the liquid gradient over the plate
by direct visual observation.
B. give access to the individual trays for
cleaning, maintenance and installation.
C. guard against foaming & entrainment by dumping
antifoaming agent through it.
D. all (a), (b) and (c).

Answer 243

B. give access to the individual trays for
cleaning, maintenance and installation

Question 244

Back-trapping in a distillation column results due to

A. low gas velocity.
B. high gas velocity.
C. excessive liquid gradient over the tray.
D. low reflux ratio.

Answer 244

C. excessive liquid gradient over the tray.

Question 245

For a cylinderical vessel of moderate height, the weld joint
efficiency for joints parallel to the cylinderical axis is given
as 1.0, while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using
code formula for an internally pressurised cylinderical
vessel, what value of weld joint efficiency should be used
?
A. 0.8
B. 0.9
C. 1.0
D. (0.8)0.5

Answer 245

A. 0.8

Question 246

Diameter of bubble caps used in high pressure columns
is __________ as compared to that used in identical
vacuum columns.
A. less
B. more
C. same
D. either (a) or (b); no generalisation can be made

Answer 246

B. more

Question 247

The ideal size of round bubble caps to be used in
industrial distillation column having a diameter of 3-6
metres is __________ cms.
A. 5
B. 15
C. 7.5
D. 50

Answer 247

B. 15

Question 248

Lap joints are preferred for plates having thickness
__________ mm.

A. < 12.5
B. > 3
C. > 5
D. 5-10

Answer 248

B. > 3

Question 249

In a distillation column, minimum clearance to be
maintained betweeen the overflow weir and the last row
of the bubble caps is __________ cms.
A. 2.5
B. 7.5
C. 15
D. 20

Answer 249

B. 7.5

Question 250

Which of the following lengths of heat exchanger tubes
are normally not used in practice?
A. 2.5 metres
B. 6 metres
C. 10 metres
D. 0.5 metre

Answer 250

C. 10 metres

Question 251

A pipe is generally made of circular cross-section,
because a circular cross-section has the
A. higher structural strength.
B. lowest surface area requirement for a given
volume.
C. both (a) & (b).
D. none of these.

Answer 251

C. both (a) & (b).

Question 252

In case of a shell and tube heat exchanger, the effect of
L/D on inside film heat transfer co-efficient (hi) vanishes
after a Reynold number of
A. 1000
B. 3000
C. 5000
D. 10000

Answer 252

D. 10000

Question 253

Equivalent diameter for heat transfer calculation for a duct
of square cross-section having each side as ‘d’ will be
A. d
B. d0.5
C. 2πd
D. 2d

Answer 253

A. d

Question 254

A cylindrical storage tank can have a self-supported
conical roof,
A. if its diameter is less than 15-20metres.
B. if its diameter is more than 50 meters.
C. if the thickness of the roof is more than that of the
cylindrical shell.
D. irrespective of its diameter.

Answer 254

A. if its diameter is less than 15-20metres.

Question 255

For high pressure process equipments/vessels, the
connected nozzle should be
A. welded
B. screwed
C. flanged
D. brazed

Answer 255

C. flanged

Question 256

Smoker’s equation for the calculation of number of
equilibrium stages in a continuous binary distillation
column is used, when the
A. relative volatility is close to one (e.g.,
separation of close boiling isomers).
B. feed is not at its bubble point.
C. number of equilibrium stages in only stripping
section is to be calculated.
D. number of equilibrium stages required is likely to
be very small.

Answer 256

A. relative volatility is close to one (e.g.,
separation of close boiling isomers).

Question 257

Column support for the roof of cylindrical storage tank
must be provided for
A. small diameter tanks.
B. large diameter tanks.
C. small diameter tall tanks.
D. all tanks irrespective of their heights and
diameters.

Answer 257

B. large diameter tanks.

Question 258

For a cylinderical internally pressurised vessel, which of
the following closure types would withstand highest
pressure, if each closure is of the same material and
thickness?
A. hemispherical
B. ellipsoidal (2 : 1)
C. conical
D. flat plate

Answer 258

B. ellipsoidal (2 : 1)

Question 259

In inclined long tube vertical evaporators, the tubes are
inclined at an angle of

A. 15°
B. 90°
C. 45°
D. 60°

Answer 259

C. 45°

Question 260

In a continuous distillation column, the optimum reflux
ratio ranges from __________ times the minimum reflux
ratio.
A. 1.1 to 1.5
B. 1.6 to 2
C. 2.2 to 2.6
D. 2.7 to 3

Answer 260

A. 1.1 to 1.5

Question 261

The wall thickness for a large high pressure pipeline is
determined by the consideration of the
A. axial tensile stress in the pipe.
B. forces exerted by static and dynamic action at
bends.
C.circumferential pipewall tension.
D. temperature stresses.

Answer 261

C.circumferential pipewall tension

Question 262

In the case of a shell and tube heat exchanger, the
logarithmic mean temperature difference

A. is always less than arithmetic average value.
B. is always more than arithmetic mean value and
the geometric mean value.
C. is always less than arithmetic mean value, but
more than geometric mean value.
D. may be either more or less than geometric mean
and arithmetic mean value depending upon
whether the flow of stream is co-current or
counter-current.

Answer 262

A. is always less than arithmetic average value.

Question 263

Skirt support is the most suitable for supporting
__________ vessels.
A. small horizontal
B. large horizontal
C. tall vertical
D. thick walled

Answer 263

C. tall vertical

Question 264

Baffles may be eliminated for
A. low viscosity liquids (< 200 poise).
B. high viscosity liquids (> 600 poise).
C. large diameter tanks.
D. none of these.

Answer 264

B. high viscosity liquids (> 600 poise)

Question 265

Generally, as the length of the liquid path on a tray is
increased beyond 5 ft, the overall column efficiency
A. increases
B. decreases
C. remains same
D. may increase or decrease depending upon the
plate spacing

Answer 265

A. increases

Question 266

In packed absorption tower, onset of flooding usually
occurs at a pressure drop of about __________ mm of
water column per metre height of packing.
A. 25-50
B. 50-75
C. 200-250
D. 750-1000

Answer 266

B. 50-75

Question 267

For pipe flows, head is proportional to __________ at
constant capacity (where D = pipe diameter ).
A. 1/D
B. 1/D2
C. 1/D5
D. D2

Answer 267

C. 1/D5

Question 268

The minimum tray spacing in distillation column of
diameter less than 3 ft is normally __________ inches.
A. 6
B. 18
C. 24
D. 34

Answer 268

A. 6

Question 269

Oxygen carrying pipelines in chemical industries are
coloured with __________ colour.
A. yellow
B. black
C. blue
D. red

Answer 269

C. blue

Question 270

Normally, the ratio of the total riser area to the tower cross
sectional area (for bubble cap towers of diameter more
than 3 ft) is around
A. 0.4-0.6
B. 0.35-0.75
C. 0.1-0.2
D. 0.55-0.85

Answer 270

C. 0.1-0.2

Question 271

Pick out the wrong statement about the design of seive
plate column and the bubble cap column.
A. The downcomer design and the residence time in
the downcomer is almost same for seive plate and
bubble cap columns.
B. Weir length for a bubble cap plate is the same as
that for the seive plate.
C. Weir height for a bubble cap plate column is
the same as that for a seive plate column.
D. Weir height in case of a bubble cap plate ranges
from 50 to 150 mm and is higher than the seive
plate.

Answer 271

C. Weir height for a bubble cap plate column is
the same as that for a seive plate column.

Question 272

Maximum size of the raschig rings used in a packed tower
is about __________ of the coloumn diameter.
A. 1/10th
B. 1/20th
C. 1/30th
D. 1/50th

Answer 272

C. 1/30th

Question 273

The type of stress developed in a metallic bar on
subjecting it to a change in temperature without allowing
it to be deformed is __________ stress.
A. shear
B. tensile
C. compressive
D. thermal

Answer 273

D. thermal

Question 274

The safe distance of habitation from a hazardous
chemical plant (TLV of its product < 1000 ppm) should be
about __________ kms.
A. 1
B. 5
C. 15
D. 25

Answer 274

D. 25

Question 275

Pick out the wrong statement pertaining to a shell and
tube heat exchanger.
A. The minimum value of baffle spacing is 50 mm.
B. The maximum value of baffle spacing is equal to
the I.D. of the shell.
C. The maximum unsupported tube span is
generally about 75 times tube diameter, but is
reduced to about 60 times for aluminium, copper
& alloys of these.
D. Disk and doughnut baffle is the most
commonly used baffle.

Answer 275

D. Disk and doughnut baffle is the most
commonly used baffle.

Question 276

Corrosion allowance in the design of pressure
vessel/chemical equipment is not necessary, if
A. plain carbon steel and cast iron parts are used.
B. wall thickness is > 30 mm.
C. material of construction is high alloy steel.
D. both(b) & (c).

Answer 276

D. both(b) & (c).

Question 277

Maximum allowable vapour velocity in a bubble cap tower
is determined by the
A. entrainment considerations.
B. vapour density.
C. diameter of the column.
D. none of these.

Answer 277

A. entrainment considerations.

Question 278

Normally, the plate thickness of the bottoms and roofs of
vertically cylindrical storage vessels as compared to that
of the cylindrical shell is
A. more
B. less
C. same
D. more or less depending upon the pressure &
temperature inside the vessel and the nature of
the fluid contained therein.

Answer 278

B. less

Question 279

The practical representative values of HETP for a number
of commercial operations lies within a range of
__________ metre.
A. 0.1-0.2
B. 0.2-0.5
C. 0.4-0.9
D. 1.2-1.5

Answer 279

C. 0.4-0.9

Question 280

Of the pressure vessels, with same thickness but different
diameters, which one withstands higher pressure ?
A. Larger dia vessel.
B. Smaller dia vessel.
C. Larger dia long vessel.
D. Strength of the vessel is same irrespective of the
diameter.

Answer 280

B. Smaller dia vessel.

Question 281

Reflux ratio variation in a distillation column is between
A. zero and infinity
B. zero and one
C. minimum and infinity
D. none of these

Answer 281

C. minimum and infinity

Question 282

In condenser, the cooling water is passed in the tube side
in a pass arrangement, because
A. it reduces heat transfer area.
B. more thinner tubes can be used.
C. pressure drop is reduced.
D. it makes condenser compact.

Answer 282

A. it reduces heat transfer area.

Question 283

In packed towers provided with pall rings liquid
redistributors are positioned at heights of every 6 metres
or 5-10 times the column diameter, whichever is less.
Maximum size of the pall rings should not exceed
__________ of the column diameter.
A. 1/10-1/15th
B. 1/5-1/10th
C. 1/20-1/30th
D. 1/2 to 1/4th

Answer 283

A. 1/10-1/15th

Question 284

Height of the flights in the rotary drier is in the range of
A. 0.08 to 0.12 d
B. 0.02 to 0.05 d
C. 0.2 to 0.5 d
D. 0.5 to 0.6 d

Answer 284

A. 0.08 to 0.12 d

Question 285

Vapor velocity in a distillation column for non-foaming
mixture is in the range of __________ times the flooding
velocity.
A. 0.1 to 0.3
B. 0.6 to 0.7
C. 0.85 to 0.95
D. 1.5 to 2

Answer 285

B. 0.6 to 0.7

Question 286

Cylindrical storage tanks used for the storage of volatile
liquids (e.g., naphtha) have __________ roofs.
A. conical
B. flat
C. floating
D. fixed

Answer 286

C. floating

Question 287

Larger depth of liquid on the trays of a distillation column
A. leads to high tray efficiency.
B. results in higher pressure drop per tray.
C. both (a) & (b).
D. neither (a) or (b).

Answer 287

C. both (a) & (b).

Question 288

Pick out the wrong statement.
A. Plate efficiency increases with increase in
superficial vapour velocity till entrainment limit.
B. Increase in depth of the liquid about the slots
increases the plate efficiency, particularly if the
liquid depth is < 1”.
C. Too small a plate spacing can cause a low
efficiency, if the vapour velocity is greater than the
allowable value.
D. none of these.

Answer 288

D. none of these.

Question 289

Pick out the wrong statement.
A. In practical operation, distillation towers having
diameter 3-6 metres equipped with bubble cap
(round) size of 15 cms are used.
B. Height of packing in a packed tower is about 3
times the column diameter for raschig rings and
about 5 to 10 times the column diameter for
saddle packing.
C. In a seive tray, the minimum hole diameter is
equal to the tray thickness.
D. In a stainless steel seive tray, the minimum
hole diameter is equal to 10 times the plate
thickness.

Answer 289

D. In a stainless steel seive tray, the minimum
hole diameter is equal to 10 times the plate
thickness

Question 290

In the downcomer of a distillation column, the minimum
recommended residence time is about __________
seconds.
A. 2.5
B. 5
C. 12.5
D. 17.5

Answer 290

B. 5

Question 291

For identical situation, condensing film coefficient in case
of a horizontal condenser is almost __________ the value
expected in case of vertical condenser.
A. half
B. twice
C. thrice
D. five times

Answer 291

C. thrice

Question 292

A binary liquid azeotropic mixture has boiling point lower
than either of the components, when it shows
__________ deviation from Raoult’s Law.
A. positive
B. negative
C. no
D. none of these

Answer 292

A. positive

Question 293

In which of the following evaporators, steam is fed inside
the tube while the liquor is outside the tube?
A. Long tube vertical evaporator
B. Short tube vertical evaporator
C. Horizontal tube evaporator
D. None of these

Answer 293

C. Horizontal tube evaporator

Question 294

A single pass air heater is connected to a two pass unit.
For the air flow rate and other conditions remaining the
same, the film heat transfer co-efficient for air will vary in
the ratio of

A. 2
B. 2^0.8
C. 2^0.2
D. none of these

Answer 294

B. 2^0.8

Question 295

In a multipass shell and tube heat exchanger, the baffles
on shell side is primarily provided for
A. reducing scale deposition.
B. increasing pressure drop.
C. fixing the tubes.
D. creating turbulence.

Answer 295

D. creating turbulence.

Question 296

For turbine agitator, the impeller diameter is about
A. 0.3 to 0.5 d
B. 0.1 to 0.2 d
C. 0.65 to 0.85 d
D. 0.95 d

Answer 296

A. 0.3 to 0.5 d

Question 297

If a single tube pass heat exchanger is converted to two
passes; for the same flow rate, the pressure drop per unit
length in tube side will __________ times.
A. increase by 1.8
B. decrease by 2^2
C. increase by 2^1.6
D. none of these

Answer 297

C. increase by 2^1.6

Question 298

Pick out the wrong statement pertaining to the design of a
long tube vertical evaporator.
A. Tube dia is 3-6 cms, while tube length in 3-6
metres.
B. Steam is fed to the shell, whereas the liquor is
filled inside the tube.
C. Liquor level is maintained at l/3rd to 1/2 of the
height of the tube.
D. none of these.

Answer 298

D. none of these.

Question 299

Which of the following is the most common type of baffle
used in industrial shell and tube heat exchanger ?
A. 75% cut segmental baffle.
B. 25% cut segmental baffle.
C. Orifice baffle.
D. Disk and doughnut baffle.

Answer 299

B. 25% cut segmental baffle

Question 300

What is the minimum recommended ligament for square
pitch arrangement in case of heat exchangers ?
A. 6.5 cms
B. 6.5 mm
C. Equal to tube I.D
D. Equal to tube O.D

Answer 300

A. 6.5 cms

Question 301

Pick out the correct statement
A. Centre to centre distance between two
consecutives rivets in a row is called the
pitch.
B. A rivetted joint made in overlapping plates is
called butt joint.
C. Hole size drilled in rivetted plates is less than the
actual size of the rivet.
D. none of these.

Answer 301

A. Centre to centre distance between two
consecutives rivets in a row is called the
pitch.

Question 302

Safety valves are provided in chemical equipments to
guard against excessive
A. temperature
B.pressure/pressure fluctuation
C. turbulence
D. noise

Answer 302

B.pressure/pressure fluctuation

Question 303

The equivalent diameter for pressure drop is __________
that for heat transfer.
A. smaller than
B. greater than
C. equal to
D. not related with

Answer 303

D. not related with

Question 304

Most of the storage vessels/tanks are made cylindrical,
because of the fact that a cylinder
A. has greater structural strength.
B. is easy to fabricate.
C. both (a) and (b).
D. neither (a) nor (b).

Answer 304

C. both (a) and (b)

Question 305

The distance between the top of the slots and the liquid
surface when the static liquid is just ready to flow over the
overflow weir is called
A. downcomer liquid seal
B. static submergence
C. skirt clearance
D. none of these

Answer 305

B. static submergence

Question 306

Liquid gradient over the tray results due to the
A. resistance offered to flow of liquids by caps &
risers and the flow of gas.
B. low gas velocity.
C. large plate spacing.
D. large reflux ratio.

Answer 306

A. resistance offered to flow of liquids by caps &
risers and the flow of gas.

Question 307

The centre to centre distance between two consecutive
baffles in a shell and tube heat exchanger is called the
baffle pitch or baffle spacing, which is more than 1/5th the
I.D. of the shell. Which of the following is not a function of
the baffles ?
A. To increase the residence time of shell side fluid.
B. To provide support to the tube bundle.
C. To reduce the induced vibration in the tubes.

D. To increase the tube side heat transfer co-
efficient by inducing turbulence.

Answer 307

D. To increase the tube side heat transfer co-
efficient by inducing turbulence.

Question 308

A high vapour velocity is required for high plate efficiency
in a seive plate coloumn. The satisfactory value of
operating vapor velocity for design purpose in seive plate
column is about __________ percent of the flooding
velocity.
A. 45
B. 60
C. 80
D. 95

Answer 308

C. 80

Question 309

The approximate liquid depth in an agitation tank is equal
to (where, d = tank diameter)
A. 0.5 d
B. 0.75 d
C. d
D. 2 d

Answer 309

C. d

Question 310

Baffle width is normally taken as __________ times the
tank diameter.
A. 0.1-0.12
B. 0.4-0.5
C. 0.45-0.6

Answer 310

A. 0.1-0.12

Question 311

Which of the following packing materials provides for
maximum mass transfer ?
A. Lessig rings.
B. Raschig rings.
C. Cross-partition rings.
D. All give the same value.

Answer 311

C. Cross-partition rings.

Question 312

__________ of water makes it a widely used coolant in
heat exchangers.
A. Low corrosiveness
B. Low dirt factor
C. High specific heat
D. Low viscosity

Answer 312

C. High specific heat

Question 313

Fouling factor must be included in the calculation of
overall design heat transfer coefficient, when the liquid
A. containing suspended solids flows at low
velocity.
B. containing suspended solids flows at high
velocity.
C. is highly viscous.
D. is of high specific gravity.

Answer 313

A. containing suspended solids flows at low
velocity.

Question 314

Overall mass transfer co-efficient in case of absorption of
__________ in water is based on the gas film co-efficient
only, as the mass transfer process is gas film (phase)
controlling.
A. CO2
B. SO2
C. NH3
D. none of these

Answer 314

C. NH3

Question 314

Lug support is meant for supporting __________ vessels.
A. large horizontal cylindrical
B. tall but empty
C. small
D. thick walled tall

Answer 314

C. small

Question 315

Which tube arrangement in a heat exchanger would
facilitate highest heat transfer rate?
A. Triangular pitch.
B. Square pitch.
C. Diagonal square pitch.
D. Heat transfer rate is independent of tube
arrangement.

Answer 315

A. Triangular pitch.

Question 316

In case of 1.5” heat exchanger tubes, the inside flow area
__________ with decrease in BWG.
A. increases
B. decreases
C. remains same
D. none of these

Answer 316

B. decreases

Question 317

Cylindrical pressure vessels in horizontal condition is
generally supported on a __________ support.

A. lug
B. skirt
C. saddle
D. guy wire

Answer 317

C. saddle

Question 318

Welded joint efficiency in the design of chemical process
equipment is taken as
A. 0.55
B. 0.75
C. 0.85
D. 0.95

Answer 318

C. 0.85

Question 319

The thickness of segmental baffles (25 -35% cut
truncated plates usually) is generally __________ the
tube wall thickness.
A. equal to
B. twice
C. four times
D. half

Answer 319

B. twice

Question 320

The safe height (h) to diameter (d) ratio (i.e., h/d) for
liquid/petro fuel storage tank of capacity more than 45
kilolitres is less than
A. 1
B. 2
C. 3
D. 3.5

Answer 320

A. 1

Question 321

For given number of passes, pitch & tube diameter, the
maximum number of tubes that can be accommodated in a shell of tripled inside diameter will be __________
times.
A. about 9
B. considerably more than 9
C. considerably less than 9
D. about 3

Answer 321

B. considerably more than 9

Question 322

The ratio of linear stress to linear strain is termed as the
A. modulus of elasticity
B. modulus of rigidity
C. bulk modulus
D. none of these

Answer 322

A. modulus of elasticity

Question 323

__________ head is the most economical for cylindrical
vessels designed for operating at high pressure (> 15
atm.).
A. Hemispherical
B. Dished
C. Ellipsoidal
D. Conical

Answer 323

C. Ellipsoidal

Question 324

Bubble cap plate column is
A. a finite stage contactor.
B. used only for distillation, not for absorption.
C. a differential stage contactor.
D. a continuous contactor.

Answer 324

A. a finite stage contactor.

Question 325

In seive plate column, holes are drilled or punched in sizes
ranging from 2.5 to 12 mm (5 mm being widely used). The
hole pitch is normally __________ times the hole
diameter to give the required hole area.
A. 0.5 to 1.5
B. 2.5 to 4.0
C. 5 to 10
D. 10 to 15

Answer 325

B. 2.5 to 4.0

Question 326

Pick out the wrong statement.
A. Rivetting provides a permanent fastening
method.
B. The joint made by overlapping of one plate
over the other, and then rivetting the two
plates together with two rows of rivets is
called ‘double rivetted butt joint’.
C. Shank diameter of the rivets should be less than
the size of the hole drilled in the plate for rivetting.
D. The efficiency of a rivetted joint is the ratio of the
strength of the rivetted joint to the strength of the
solid plate.

Answer 326

B. The joint made by overlapping of one plate
over the other, and then rivetting the two
plates together with two rows of rivets is
called ‘double rivetted butt joint’.

Question 327

The force due to wind load acting on a tall vessel depends
upon its
A. shape.
B. outside diameter.
C. height.
D. all (a), (b) & (c).

Answer 327

D. all (a), (b) & (c).

Question 328

Bubble cap diameter used for the distillation column
having diameter ranging from 1.5 to 4.5 metres is about
__________ mm.
A. 10
B. 50
C. 100
D. 150

Answer 328

C. 100

Question 329

Power required for agitation depends upon the
A. height & properties of the liquid.
B. agitator type & speed of agitation.
C. size of agitator & the tank.
D. all (a), (b) and (c).

Answer 329

D. all (a), (b) and (c).

Question 330

Tube height in a calendria type evaporator is normally less
than __________ metres.
A. 1
B. 2
C. 3.5
D. 5.5

Answer 330

B. 2

Question 331

Pick out the wrong statement.
A. Lug supports are less expensive than other type
of supports.
B. A pipe is differentiated from a tube by the fact that
a pipe has a greater wall thickness compared to
the tube.
C. A reducer is used to change the direction of a
pipe in a straight run.
D. The method of fixing tubes to a tube sheet by
expanding is called ‘tube rolling’.

Answer 331

C. A reducer is used to change the direction of a
pipe in a straight run.

Question 332

For a 25 mm hole drilled in plates to be rivetted, the shank
diameter of the rivet should be __________ mm.
A. 25
B. 23
C. 26
D. 27

Answer 332

B. 23

Question 333

Optimum economic pipe diameter for fluid flow is
determined by the
A. viscosity of the fluid.
B. density of the fluid.
C. total cost considerations (pumping cost plus
fixed cost of the pipe).
D. none of these.

Answer 333

C. total cost considerations (pumping cost plus

Question 334

Pressure differential maintained across a continuous
rotary vacuum filter is in the range of __________ mm Hg
column.
A. 50 to 100
B. 100 to 150
C. 250 to 500
D. 600 to 700

Answer 334

C. 250 to 500

Question 335

Vertical storage vessels are never supported by
__________ support.
A. bracket
B. saddle
C. skirt
D. lug

Answer 335

B. saddle

Question 336

In a double pipe (concentric) heat exchanger, the
hydraulic radius for heat transfer (for a fluid flowing
through the annulus) would be
A. same as that for fluid flow.
B. less than that for fluid flow.
C. more than that for fluid flow.
D. D2 - D1 (D1 and D2 are I.D. of inner and outer
pipes respectively).

Answer 336

C. more than that for fluid flow.

Question 337

Elastic failure of a material occurs, when the tensile stress
equals yield strength, yield point or the elastic limit. Also,
the elastic failure occurs according to maximum strain
theory, when the maximum tensile strain equals (where,
σ = yield strength and E = modulus of elasticity)

A. E
B. σ
C. σ/E
D. E/σ

Answer 337

C. σ/E

Question 338

In a pressure vessel containing multiple openings of
various dimensions at different parts, stress concentration
at the edges of the opening is maximum which becomes
negligibly small beyond the area covered by __________
times the hole diameter.
A. two
B. five
C. ten
D. twenty

Answer 338

A. two

Question 339

What is the slope of the feed line, if the feed to a distillation
column is a saturated liquid ?
A. 0
B. ∞
C. > 1
D. < 1

Answer 339

B. ∞

Question 340

Filtration rate is affected by the
A. pressure drop across the cake & filter medium.
B. cake & filter medium resistance.
C. area of filtering surface & the viscosity of filtrate.
D. all (a), (b) and (c).

Answer 340

D. all (a), (b) and (c).

Question 341

Liquid gradient over a tray can be minimised by

A. providing a higher skirt clearance or a higher weir.
B. decreasing the number of rows of caps through
which the liquid flows or by decreasing the
velocity of liquid flow past the caps or by reducing
the distance along the tray through which the
liquid must flow.
C. using split flow, radial flow or cascade flow for
column diameter large than 4 ft.
D. all (a), (b) and (c).

Answer 341

D. all (a), (b) and (c).

Question 342

In a shell and tube heat exchanger for a given heat
transfer surface area, smaller diameter tubes are
favoured as compared to larger diameter ones ; because
the smaller diameter tubes
A. are easier to clean.
B. are less prone to fouling.
C. can be fitted into a smaller shell diameter
hence the cost of the heat exchanger would
be less.
D. none of these.

Answer 342

C. can be fitted into a smaller shell diameter
hence the cost of the heat exchanger would
be less.

Question 343

Le/D for 90° elbow (medium radius) and 90°square elbow
would be respectively around
A. 25 and 60
B. 3 and 5
C. 100 and 250
D. 250 and 600

Answer 343

A. 25 and 60

Question 344

__________ heat exchanger is also known as ‘hair pin
type’ exchanger,
A. Double pipe
B. Finned
C. Plate type
D. Regenerative

Answer 344

A. Double pipe

Question 345

What is the value of ‘q’ for saturated vapor feed to a
distillation column ?(where q = fraction of the feed stream
that is liquid.)
A. 0
B. 1
C. <0
D. > 1

Answer 345

A. 0

Question 346

In hydrostatic testing of welded pipe (for leakage, strength
etc.) the ratio of minimum hydrostatic test pressure to
internal design pressure is around
A. 0.5
B. 1.5
C. 2.5
D. 3.5

Answer 346

B. 1.5

Question 347

Frame thickness in the plate and frame filter press is
normally in the range of __________ inches.
A. 0.25 to 4
B. 0.25 to 8
C. 1 to 5
D. 1 to 12

Answer 347

B. 0.25 to 8

Question 348

Cylinderical shell thickness of rotary drier is generally
__________ mm.
A. 2-3
B. 18-22
C. 6-8
D. 12-15

Answer 348

C. 6-8

Question 349

The ratio of lateral strain to linear strain is termed as the
A. Poisson’s ratio
B. bulk modulus
C. modulus of elasticity
D. shear modulus

Answer 349

A. Poisson’s ratio

Question 350

The distance between the centre of a rivet hole to the
nearest edge of the plate is called
A. pitch
B. margin
C. back pitch
D. none of these

Answer 350

B. margin

Question 351

Mc Cable Thiele method used for finding theoretical
stages in a distillation column assumes that the
A. sensible heat differences are small, because the
temperature changes from tray to tray is small.
B. Trouton’s rule is applicable.
C. liquid/vapor loading across the column remains
constant.
D. all (a), (b) and (c).

Answer 351

D. all (a), (b) and (c).

Question 352

A minimum clearance of about __________ mm is
maintained between the distillation column wall and the
bubble cap.
A. 19
B. 38
C. 76
D. 95

Answer 352

B. 38

Question 353

Pick out the wrong statement.
A. If sufficient residence time (around 8 seconds) is
not proivided to the downcoming liquid in the
downcomer, it may entrain some vapour.
B. The liquid head in the downcomer should not be
greater than one half the plate spacing to avoid
flooding.
C. The dischare end of the downcomer must project
far enough into the tray liquid so that no gas
bubbles can enter the open end and by pass the
bubble caps.
D. none of these.

Answer 353

D. none of these.

Question 354

Pick out the wrong statement pertaining to shell and tube
heat exchanger.
A. Clearance between shell & baffles and between

tube & baffles should be minimum to avoid by-
passing of the fluid, but it should be enough to

permit the removal of tube bundle.
B. Baffles are supported independently of the tubes
by tie rods and positioned by spacers.
C. Tie rods are fixed at one end in the tube sheet by
making blind holes and the minimum number of
tie rods is 4 with at least 10 mm diameter.
D. Bracket supports are used for horizontal
shell, while saddle support is used for vertical
shell.

Answer 354

D. Bracket supports are used for horizontal
shell, while saddle support is used for vertical
shell.

Question 355

Wind load consideration in the design of a support can be
neglected, when the vessel is
A. tall (say 30 metres), but is full of liquid.
B. tall but empty.
C. short (< 2 m) and housed indoor.
D. none of these.

Answer 355

C. short (< 2 m) and housed indoor.

Question 356

The ratio of volumes of the mixed reactor to the plug flow
reactor (for identical feed composition, flow rate,
conversion, and for all positive reaction orders) is always
A. 1
B. < 1
C. >1
D. equal to the order of reaction

Answer 356

C. >1

Question 357

Steam economy is defined as the amount of evaporation
per unit amount of steam used, while the capacity is the
total evaporation obtained per hour. Use of multiple effect
in evaporation
A. increases capacity.
B. increases economy.
C. does not affect the capacity.
D. both ‘b’ & ‘c’.

Answer 357

D. both ‘b’ & ‘c’.

Question 358

Le/D for a Tee (used as elbow, entering run) would be
around
A. 5
B. 60
C. 200
D. 350

Answer 358

B. 60

Question 359

Log mean temperature difference in case of multi-pass
shell and tube heat exchanger is always
A. less than arithmetic mean value.
B. more than arithmetic mean value.
C. more than geometric mean value.
D. both(b) & (c).

Answer 359

A. less than arithmetic mean value.

Question 360

Tubes are fixed to the tube sheet (a thick circular metallic

plate) by the method of tube rolling and brazing (non-
removable) or ferrule connection (removable). Thickness

of the tube, sheet is normally __________ the outside
diameter of the tube but in no case it should be less than
22 mm (7/8”).
A. half
B. three fourth
C. equal to
D. 1.5 times

Answer 360

C. equal to

Question 361

A shell may by termed as thin if its thickness to diameter
ratio is less than 0.1. The factor which can be neglected
in the calculation of membrane stresses is
A. bending
B. deformation
C. shear
D. elongation

Answer 361

A. bending

Question 362

Scale up problem in design based on the similarity
concept takes into account __________ similarity.
A. geometrical
B. kinematic
C. dynamic
D. all (a), (b) and (c)

Answer 362

D. all (a), (b) and (c)

Question 363

__________ closure is the weakest enclosure for
cylindrical vessels.
A. Hemispherical
B. Torispherical
C. Conical or flat plate
D. Elliptical

Answer 363

C. Conical or flat plate

Question 364

Which of the following efficiencies can be greater than
100% ?
A. Overall plate efficiency.
B. Murphree plate efficiency.
C. Point efficiency.
D. None of these.

Answer 364

B. Murphree plate efficiency.