Process Equipment and Plant Design

Question 1

Speed of industrial paddle agitator ranges from __________ rpm.
1 to 5
20 to 100
500 to 750
1000 to 2000

Answer 1

20 to 100

Question 2

_________ strain is measured using a ‘strain rosetter’.
Volumetric
Shear
Linear
none of these

Answer 2

Linear

Question 3

Thin spherical shells subjected to internal pressure, develop __________ stresses.
radial
circumferential
both (a) & (b)
neither (a) nor (b)

Answer 3

radial

Question 4

24.
With increase in the reflux ratio for a fixed production from a continuous binary distillation column, the __________ decreases.

fixed charges initially
running cost of cooling water for condenser
vapour & liquid load both
running cost of steam for reboiler

Answer 4

fixed charges initially

Question 5

The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is
0
∞
1
minimum

Answer 5

∞

Question 6

Vertical vessels are not supported by
brackets
skirts
columns
saddles

Answer 6

saddles

Question 7

With increase in pressure drop (for a given particle size), the dust collection efficiency of a cyclone separator will
increase
decrease
remain unaffected
increase or decrease depending on the nature of the dust.

Answer 7

increase

Question 8

Spherical shaped pressure vessel is considered to be the most ideal, because it can
withstand higher pressure for a given metallic shell thickness.
be fabricated very easily.
be designed without wind load considerations.
be supported very easily.

Answer 8

withstand higher pressure for a given metallic shell thickness.

Question 9

An adequate clearance between the tray and the shell wall of a distillation column is provided to
drain the liquid from the tray when the unit is not in operation.
allow for thermal expansion and facilitate installation.
avoid back-trapping.
none of these.

Answer 9

allow for thermal expansion and facilitate installation

Question 10

Overall tray efficiency of a distillation column is the ratio of the number of
overall gas transfer units to the number of ideal trays required.
ideal trays required to the number of real trays required.
real trays required to the number of ideal trays required.
none of these.

Answer 10

ideal trays required to the number of real trays required.

Question 11

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

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.

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.

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.

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 11

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 12

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

Answer 12

30

Question 13

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.
0.1 to 0.25
0.3 to 0.5
0.5 to 0.6
0.65 to 0.80

Answer 13

0.1 to 0.25

Question 14

In a __________ rivetted joint, the rivets in the various rows are opposite to each other.
zig-zag
chain
diamond
none of these

Answer 14

chain

Question 15

Pick out the wrong statement:

The tensile strength of a brittle material is less than its compressive strength.

The compressive strength of a ductile materia] is less than its tensile strength.

In a thick cylindrical shell, the hoop stress is maximum at the inner radius.

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

Answer 15

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

Question 16

Generally, elliptical dished heads

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 .

resist half the pressure rating compared to hemi spherical head provided on the cylindrical shell of the same thickness and diameter.

are approximately as strong as seamless cylindrical shell having the corresponding I.D and O.D.

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

Answer 16

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

Question 17

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

Plate tower is perferred, if interstage cooling is required to remove heats of reaction or solution.

Plate tower is preferred over packed tower, if the operation involves liquids containing dispersed solids.

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

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 17

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 18

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

Answer 18

pd/2t

Question 19

Le/D for fully open gate valves would be

much more than that for f
ully open globe valves.
much less (say 2% than that for fully open globe valves).

around 7.

both (b) and (c).

Answer 19

both (b) and (c).

Question 20

LMTD correction factor is used in heat exchanger design for

double pipe heat exchanger.

multipass shell and tube heat exchanger.

fouling fluids.

counter flow of hot and cold fluids.

Answer 20

multipass shell and tube heat exchanger.

Question 21

Floating head heat exchangers are used for the

heat transfer between corrosive fluids.

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

co-current heat transfer systems.

counter-current heat transfer systems.

Answer 21

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

Question 22

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

1” dia cap with 0.5” dia riser.
6” dia cap with 4” dia riser.
8” dia cap with 1” dia riser.
4” dia cap with 8” dia riser.

Answer 22

6” dia cap with 4” dia riser.

Question 23

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.
nozzle or rim
flared out
fluid in
ring plate

Answer 23

nozzle or rim

Question 24

In case of a continuous distillation column, increase in reflux ratio may result in the
lower fixed charges for the column.
greater cost for the reboiler heat supply.
greater cost for the condenser coolant.
all (a), (b) and (c).

Answer 24

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

Question 25

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

Answer 25

8

Question 26

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

Answer 26

more

Question 27

Which of the following factors affect the pressure drop in a co-current gas-liquid absorption packed tower ?
Size, shape, orientation and surface of the packing particles.
Density and viscosity of fluids.
Fluid flow rates.
All (a), (b) and (c).

Answer 27

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

Question 28

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.
0.3 to 0.8
1.25 to 3.125
3.5 to 7.0
8-12

Answer 28

1.25 to 3.125

Question 29

Rivets are generally specified by the
head diameter
shank diameter
overall length
none of these

Answer 29

shank diameter

Question 30

Length to diameter ratio of most rotary driers is in the range of
1 to 2
4 to 10
10 to 20
20 to 30

Answer 30

4 to 10

Question 31

Needle valves are generally not used for
very large diameter pipes.
high pressure throttling service.
very accurate flow control.
smaller sizes of pipe.

Answer 31

very large diameter pipes.

Question 32

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

flow rates of each fluid.

type and size of packing.

concentration of each fluid.

all a, b & c.

Answer 32

all a, b & c.

Question 33

Pick out the wrong statement.

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

Liquid metals and dowtherm are used for very high temperature heating.

In a shell and tube heat exchanger, high pressure fluid is generally routed through the tube.

A loop seal or U-seal is provided in a vertical condenser sub-cooler to prevent quick draining of the condensate.

Answer 33

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

Question 34

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

increases
decreases
remain unaffected
none of these

Answer 34

decreases

Question 35

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

central dished section and corner torus section.

corner torus section and central dished section.

central dished section and straight flange section.

straight flange section and corner torus section.

Answer 35

central dished section and corner torus section.

Question 36

Number of evaporators which can be used in service in a multiple effect evaporation system is limited by the
practical limit reached, due to low heat transfer rate because of inadequate temperature difference.
economic limit reached, when the plant cost exceeds the saving of steam.
both (a) & (b).
neither (a) nor (b).

Answer 36

both (a) & (b).

Question 37

Which of the following is used to set the diameter of the distillation column ?
Number of theorectical plates.
Static submergence.
Allowable vapour velocity.
Length of straight rectangular weir on cross-flow tray.

Answer 37

Allowable vapour velocity.

Question 38

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

Answer 38

all ‘a’, ‘b’ & ‘c’.

Question 39

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

Answer 39

smaller reactor should come first.

Question 40

In a shell and tube heat exchanger, tube side __________ of the mass velocity.
heat transfer co-efficient is proportional to 0.8th power
pressure drop is proportional to the square
both ‘a’ & ‘b’
neither ‘a’ nor ‘b’

Answer 40

both ‘a’ & ‘b’

Question 41

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?
Sorel-Lewis method.
McCabe-Thiele’s method.
Ponchon-Savarit method.
none of these.

Answer 41

Sorel-Lewis method.

Question 42

Saddle supports are used for supporting __________ vessels.
horizontal cylinderical
tall vertical
thick walled vertical
thick spherical

Answer 42

horizontal cylinderical

Question 42

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.
5 to 10
15 to 30
40 to 50
55 to 75

Answer 42

15 to 30

Question 43

In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less.
2-3
5-8
10-15
20-25

Answer 43

5-8

Question 44

Optimum reflux ratio in a continuous distillation column is determined by the
maximum permissible vapour velocity.
flooding limit of the column.
total cost consideration (fixed cost of the column plus the cooling water & steam cost).
none of these.

Answer 44

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

Question 45

Cooling water fouling factors vary in the range of 0.001 to 0.003
(BTU/hr.ft2 . °F)-1
(kcal/hr.m2 .°C)-1
(W/m2.°K)-1
(kcal/hr. m. °C)-1

Answer 45

(BTU/hr.ft2 . °F)-1

Question 46

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

Answer 46

0.2 D

Question 47

The maximum liquid gradient over a tray must not exceed
0.5” -1.25”.
2”-3.5”.
5”.
half the tray spacing.

Answer 47

0.5” -1.25”.

Question 48

An underdesigned steam trap will
waste steam.
destroy itself of acceleration wear due to rapid recycling.
back up condensate and cause water hammer in steam line.
none of these.

Answer 48

back up condensate and cause water hammer in steam line.

Question 49

The slope of the feed line in distillation opeartion is given by (where, q = fraction of the feed stream that is liquid.)
-q
-q/(1-q)
-q/(q-1)
none of these

Answer 49

-q/(1-q)

Question 50

Fresh water carrying pipelines in chemical industries are coloured with __________ color.
sea green
brown
yellow
red

Answer 50

sea green

Question 51

Which of the following material is seldom used for pressure vessel construction ?
Rimmed steel
Mild steel
Killed steel
Semi-killed steel

Answer 51

Rimmed steel

Question 52

The ratio of shear stress to shear strain is called
bulk modulus
shear modulus
modulus of rigidity
modulus of elasticity

Answer 52

shear modulus

Question 53

25 per cent cut segmental baffle means that the baffle
height is 75% of the I.D. of the shell.
height is 25% of the I.D. of the shell.
spacing is 75% of its height.
width is 25% of its height.

Answer 53

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

Question 54

Liquid/petroleum fuel storage tanks are built underground (as in case of petrol pumps), when the storage capacity is less than __________ kilolitres.
20
30
45
85

Answer 54

45

Question 55

Le/D for fully open globe value may be around
10
25
75
300

Answer 55

300

Question 56

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

Answer 56

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

Question 57

Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column.
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.
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.
Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.
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 57

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

Question 58

With increase in the number of shell passes, the value of FT
increases
decreases
remains same
remains same, only if the number of tube passes does not change.

Answer 58

increases

Question 59

Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter.
1.5 to 2
2.5 to 5
5 to 10
10 to 15

Answer 59

2.5 to 5

Question 60

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.
3-5
5-11
8-15
12-18

Answer 60

5-11

Question 61

The stress developed in a material without any permanent set is called the
ultimate stress
yield stress
elastic limit
breaking stress

Answer 61

elastic limit

Question 62

In a shell and tube heat exchanger, the ‘tube pitch’ is defined as the
O.D. of the tube for square pitch.
shortest distance between two adj acent tube holes.
shortest centre to centre distance between adjacent tubes.
none of these.

Answer 62

shortest centre to centre distance between adjacent tubes.

Question 63

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

Answer 63

Reflux is not a saturated liquid.

Question 64

Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 - 1.4 cp and relative volatility < 4) (where η = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi)
η = 17 - 61.1 log μ
η = 24.6Δp/μ
η = 1.66 - 0.25 log μ
η = 0.25 log μ - 1.67

Answer 64

η = 17 - 61.1 log μ

Question 65

The value of fouling factor depends upon the
characteristic of process fluid.
velocity of process fluid containing suspended solids.
suspended solids in the fluid.
all (a), (b) and (c).

Answer 65

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

Question 66

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

Answer 66

10

Question 67

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.
2
1/2
4
8

Answer 67

8

Question 68

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
(1.2)^3/2
(1.2)^3/5
(1.2)^2/3
(1.2)^5/3

Answer 68

(1.2)^5/3

Question 69

In a heat exchanger, shell side fluid velocity can be changed by changing the tube
layout
pitch
both (a) & (b)
neither (a) nor (b)

Answer 69

both (a) & (b)

Question 70

Where does the maximum tensile strength occur in a thick cylindrical vessel subjected to internal pressure ?
At the inner surface.
At the mid thickness of the cylindrical wall.
At the outer surface.
None of these.

Answer 70

At the inner surface.

Question 71

It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than
0.99
0.95
0.80
0.55

Answer 71

0.80

Question 72

A rivetted joint does not fail by __________ of rivets.
tearing
shearing
tearing of the plate across a row
none of these

Answer 72

none of these

Question 73

Bracket supports are the most suitable for supporting __________ vessels.
thick walled vertical
horizontal
thin shperical (e.g. Horton sphere)
none of these

Answer 73

thick walled vertical

Question 74

In a multipass shell and tube heat exchanger, the shell side cross flow area does not depend upon
baffle spacing
clearance
pitch
none of these

Answer 74

none of these

Question 75

Two iron pipes of the same nominal diameter but different schedule numbers will have the same
inside diameter
outside diameter
wall thickness
none of these

Answer 75

inside diameter

Question 76

Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2.°C.
1250
2500
7500
15000

Answer 76

7500

Question 77

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.
5
20
35
55

Answer 77

20

Question 78

In chemical process equipments, the conical bottom heads used, usually has an apex angle of
20°
40°
60°
80°

Answer 78

60°

Question 79

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.
25
50
75
150

Answer 79

75

Question 80

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
more
same
less
twice

Answer 80

less

Question 81

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

Answer 81

ultimate stress to working stress.

Question 82

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.
1-5
20-40
100-150
1000-1500

Answer 82

20-40

Question 83

__________ tray arrangement is recommended for distillation column having diameter upto 4 ft.
Radial flow
Cross flow
Split flow
Cascade

Answer 83

Cross flow

Question 84

What is the value of ‘q’ for saturated liquid feed to a distillation column ?
0
<1
1
>1

Answer 84

1

Question 85

In perforated plate towers, the
hole sizes may be around 1/8” or 3/16”.
total hole area may be around 6 to 15% of tower cross-sectional area.
pressure drop is less compared is similar bubble cap towers.
all (a), (b) and (c).

Answer 85

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

Question 86

The main purpose of providing stepping on the trays is to
increase the residence time.
decrease the pressure drop.
facilitate handling of large flow rate of liquid.
improve the flow condition.

Answer 86

facilitate handling of large flow rate of liquid.

Question 87

The operating pressure drop range in a bag filter is about __________ mm water gauge.
50-150
5-10
500-1500
1500-2500

Answer 87

50-150

Question 88

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.
Flat plate
Hemispherical
Torispherical
Ellipsoidal

Answer 88

Ellipsoidal

Question 89

For laminar flow (NRe < 2100) in steel pipe, the optimum inside pipe diameter is given by
Di, opt = 3 Q^0.36 ρ^0.18
Di, opt = 3.9 Q^0.45 . ρ^0.23
Di, opt = 7.6 Q^0.36 . ρ^0.9
Di, opt = 3 Q^0.36 . ρ^1.86 μ0.08

Answer 89

Di, opt = 3 Q^0.36 ρ^0.18

Question 90

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

Answer 90

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

Question 91

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

Answer 91

less

Question 92

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

Answer 92

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

Question 93

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.

The pressure drop due to the caps & slots and the static submergence should be as high as practicable for reasonable operation.
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.
The dimensionless ratio of liquid gradient to pressure drop head caused by the bubble cap assembly should be less than 0.4.
none of these.

Answer 93

none of these.

Question 94

Speed of the drum of the rotary vacuum filter normally ranges from __________ rpm.
0.1 to 2
5 to 7
3 to 8
8 to 15

Answer 94

0.1 to 2

Question 95

A stuffing box is used for
absorbing the contraction/expansion of pipeline due to temperature changes.
prevention of fluid leakage around moving parts.
facilitating smooth opening and closing of a valve.
reducing the resistance of fluid flow.

Answer 95

prevention of fluid leakage around moving parts.

Question 96

Pressure drop (Δp) and the superficial gas mass velocity (G) in case of packed absorption tower operating in the preloading range are related as
Δp = G
Δp = G^0.5
Δp = G^2
Δp = 1/G^0.6

Answer 96

Δp = G^2

Question 97

Pick out the wrong statement.
In an agitated vertical cylinderical reaction vessel, the:

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

Answer 97

dished bottom vessel has very high power consumption.

Question 98

Tube wall thickness depends on the cor-rosiveness 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.
16
19
28
38

Answer 98

19

Question 99

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 viscoisty above __________ poise.
300
600
1000
1500

Answer 99

600

Question 100

The dust collection efficiency of a cyclone separator
decreases with increase in gas flow rate.
is inversely proportional to the mass of the dust particle.
is directly proportional to the radius of the dust particle path.
none of these.

Answer 100

none of these.

Question 101

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
∞
1
20.8
2

Answer 101

1

Question 102

Which of the following types of reactors is the safest from operation point of view ?
A vapor phase reactor.
Pot type reactor.
A liquid phase reactor.
A liquid phase catalytic reactor.

Answer 102

A vapor phase reactor.

Question 103

In a bag filter, the pressure drop increases directly as the
density of the gas, but is independent of the viscosity of the gas.
density of the gas and inversely as viscosity of the gas.
viscosity of the gas and inversely as density of the gas.
none of these.

Answer 103

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

Question 104

The LMTD correction factor (FT) is applied in __________ heat exchangers.
1-1 cocurrent
double pipe
all multipass
all (involving liquid/liquid heat transfer)

Answer 104

all multipass

Question 105

Movement of pipeline caused by thermal expansion is taken care by providing
expansion joint.
changes in its direction.
change in the shape of pipeline.
all (a), (b) and (c).

Answer 105

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

Question 106

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

Answer 106

decreases upwards.

Question 107

In the design of a paddle agitator, the ratio (paddle dia/tank dia) is normally taken as
0.1
0.8
0.25
0.5

Answer 107

0.8

Question 108

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.
working
damaging
allowable
none of these

Answer 108

damaging

Question 109

Hole diameter of the seive trays in the distillation column ranges from __________ mm.
lto3
4 to 8
3 to 12.5
12.5 to 18.5

Answer 109

3 to 12.5

Question 110

Factor of safety (i.e., overdesign factor) in heat transfer equipments is about __________ percent more than the actual/theoretical design factor.
5-10
15-20
30-35
35-40

Answer 110

15-20

Question 111

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
d1/(d1+d2)
d2/(d1+d2)
(d2+d2)/d1
(d2+d2)/d2

Answer 111

d1/(d1+d2)

Question 112

In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the
liquid gradient on the tray.
lower skirt clearance.
lower static submergence.
small downcomer liquid seal.

Answer 112

liquid gradient on the tray.

Question 113

The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability.
2
5
10
15

Answer 113

5

Question 114

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

Answer 114

D/5 or minimum 2” to 5D.

Question 115

Brass valves are usually made for pipe sizes __________ inches.
≤1
≤2
>2.5
>3.5

Answer 115

≤2

Question 116

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
increases
decreases
remains same
may increase or decrease depending upon the solubility of the gas in the liquid

Answer 116

remains same

Question 117

In a shell and tube heat exchanger, triangular pitch arrangement as compared to square pitch arrangement
results in higher shell side pressure drop.
can accomodate less number of tubes for a given shell diameter.
facilitates easier shell side cleaning; hence is more suitable for handling high dirt factor shell side fluid.
creates relatively lower turbulence on the shell side resulting in lower shell side heat transfer co-efficient.

Answer 117

results in higher shell side pressure drop.

Question 118

Pick out the wrong statement about routing of fluids in a shell and tube heat exchanger.
The corrosive and fouling fluid should be preferably routed through the tubes.
The viscous fluid should be routed through the shell side.
Lower flow rate fluid should be routed through the shell side.
Higher pressure fluid stream should be routed through the shell side.

Answer 118

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

Question 119

The necessary wall thickness for a metallic storage vessel is a function of the
ultimate tensile strength (or yield point) of the material and operating temperature.
operating pressure and welding/joint efficiency.
diameter of the vessel.
all (a); (b) and (c).

Answer 119

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

Question 120

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.
‘n’th
(1/n)th
0.5 nth
1.5 nth

Answer 120

(1/n)th

Question 121

Pick out the wrong statement
In a flanged and standard dished head, the crown radius is ≤ shell outside diameter.
In a flanged and shallow dished head, the crown radius is > shell outside diameter.
Flat head covers are most suitable for larger vessels operating at very high pressure.
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 121

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

Question 122

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

Answer 122

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

Question 123

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

Answer 123

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

Question 124

Steam is preferred to be used as a heating medium in heat exchangers, because of its
low cost.
high latent heat.
non-corrosive condensate.
high film co-efficient.

Answer 124

high latent heat.

Question 125

__________ shapedroof is the most commonly used roof for cylinderical storage tanks.
Conical
Flat
Dome
Umbrella

Answer 125

Conical

Question 126

Pick out the wrong statement pertaining to ‘Horton sphere’ used for the storage of liquid ammonia.
Diameter of Horton sphere is normally 6 to 25 metres and it is supported by 6 to 12 nos. tubular or rolled section column.
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.
Horton sphere is used for the storage of gases and volatile liquid at a moderate pressure of 1 to 10 kg/cm2 .
Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2 .

Answer 126

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

Question 127

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

Answer 127

plug flow.

Question 128

In most of the shell and tube heat exchangers, the tube pitch is generally __________ the tube diameter.
less than
1.25-1.50 times
2.5 times
one-fourth of

Answer 128

1.25-1.50 times

Question 129

In a distillation column, bubble caps are located on trays with a pitch of __________ times the outside diameter of the caps.
1.3 to 2
1.6 to 2
2.5
1.5 to 3

Answer 129

1.3 to 2

Question 130

1.2 to 3.8 cms is the value of the
downcomer liquid seal in case of a balanced tray design.
static submergence in case of a bubble cap tray for column operating under pressure (≥ 1 atm.).
skirt clearance for bubble caps.
all (a), (b) and (c).

Answer 130

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

Question 131

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

Answer 131

faulty operating procedures.

Question 132

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

Answer 132

bubble cap

Question 133

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
(ph - dh)/ph
(ph - dh . dt/2)/ph
(ph - dt)/ph
(ph - dh)/dh

Answer 133

(ph - dt)/ph

Question 134

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

Answer 134

Permissible slot velocity

Question 135

Pick out the wrong statement about distillation operation
Distillation under vacuum is a substitute for steam distillation.
In differential (simple) distillation, the vapour is removed as soon as it is formed without appreciable condensation.
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.
Flash distillation, differential distillation & steam distillation are all continuous distillation processes.

Answer 135

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

Question 136

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).
250
450
650
750

Answer 136

650

Question 136

Which of the following is the best tube material from thermal conductivity point of view alone?
Aluminium
Stainless steel
Copper
Carbon steel

Answer 136

Copper

Question 137

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

Answer 137

3

Question 138

In a shell and tube heat exchanger, the clearance of the tube is generally
not less than one-fourth of the tube diameter or 3/16”.
more than the tube diameter.
equal to the tube diameter.
more in case of triangular pitch as compared to the square pitch tube layout.

Answer 138

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

Question 139

Diameter of the seive tray column is determined by the
lower limit of vapour velocity.
upper limit of the vapour velocity.
hole diameter of the seive tray.
height of the plate spacing.

Answer 139

upper limit of the vapour velocity.

Question 140

For a given fluid, as the pipe diameter increases, the pumping cost
decreases.
increases.
remains unaffected.
may increase or decreaes depending upon whether the fluid is Newtonian or non-Newtonion.

Answer 140

decreases

Question 141

Maximum acceptable total liquid gradient over a tray is about __________ mm.
5.5
12.5
30.5
45.5

Answer 141

12.5

Question 142

In case of a ‘thin’ pressure vessel, the ratio of its diameter to wall thickness is
< 10
> 10
> 20
30

Answer 142

> 10

Question 143

High pressure fluid in a shell and tube heat exchanger should preferably be routed through the
tubes to avoid the expansion of high pressure shell construction.
shell side for smaller total pressure drop.
shell side, if the flow is counter-current and tube side if the flow is co-current.
shell side for large overall heat transfer co-efficient.

Answer 143

tubes to avoid the expansion of high pressure shell construction.

Question 144

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

Answer 144

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

Question 145

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

Answer 145

Aa = Sa

Question 146

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
hG = 1.004G^0.37
1.004G^0.8
hG = 0.0176G^0.37
0.0176G^1.37

Answer 146

hG = 1.004G^0.37

Question 147

In the agitators, the power required will be changed with the increase of diameter of agitator (D) as
D^2
D^5
D
D^9

Answer 147

D^5

Question 148

Apex angle of conical heads used in the bottom heads of chemical process equipments is usually
30°
45°
60°
75°

Answer 148

60°

Question 149

Pressure drop due to pipe fittings can be estimated by the equation ΔP/⍴ = 45*(Le/D)(v^2/2gc)
, where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of Le/D (dimensionless) for 45° elbow and 180° close return bends would be respectively around
5 and 10
45 and 75
180 and 300
300 and 500

Answer 149

45 and 75

Question 150

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

Answer 150

G^0.8

Question 151

Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is __________ the longitudinal stress.
half
equal to
twice
eight times

Answer 151

twice

Question 152

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

Answer 152

electrode area.

Question 153

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

Answer 153

1 to 1.5

Question 154

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

Answer 154

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

Question 155

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

Answer 155

S1/S2

Question 156

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

Answer 156

hold baffle in space.

Question 157

In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres ρ = apparent solid density, kg/m3 L = flow rate of dry solids, kg/see. m2 drier cross-section H = hold up of solid.)
ZH⍴/L
L/ZH⍴
H⍴/L
ZH/L⍴

Answer 157

ZH⍴/L

Question 158

In case of design of a shell and tube heat exchanger,
minimum cleaning lane of 6.5 mm is provided, when tubes are on a square pitch.
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.
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.
all (a), (b) & (c)

Answer 158

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

Question 159

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

Answer 159

σh = 2 σL

Question 160

Nominal size of a pipe is an indication of its __________ diameter.
inner
outer
approximate
none of these

Answer 160

approximate

Question 161

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

Answer 161

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

Question 162

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

Answer 162

4 to 8

Question 163

In a double pipe concentric heat exchanger, the equivalent diameter of annulus for heat transfer would be (where, D1 and D2 are I.D. of inner and outer pipes)
D2^2-D1^2/D1^2
D2 - D1
D2^2-D1^2/D2^2
none of these

Answer 163

D2^2-D1^2/D1^2

Question 164

What is the slope of the operating line in the stripping section of a distillation column ?
0
∞
> 1
< 1

Answer 164

> 1

Question 165

__________ shaped roof is most commonly used for cylindrical tanks.
Cone
Dome
Umbrella
Flat

Answer 165

Cone

Question 166

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

Answer 166

circumferential tensile

Question 167

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

Answer 167

17-34

Question 168

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

Answer 168

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

Question 169

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.
molal flow rate of vapour
vapour molecular weight
pressure and temperature
all (a), (b) and (c)

Answer 169

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

Question 170

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

Answer 170

1.5 to 2.5

Question 171

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

Answer 171

< 7

Question 172

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

Answer 172

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

Question 173

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

Answer 173

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

Question 174

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

Answer 174

decreases very rapidly

Question 175

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

Answer 175

80-100

Question 176

__________ dished head is the strongest of all.
Hemispherical
Elliptical
Torispherical
none of these

Answer 176

Hemispherical

Question 177

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

Answer 177

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

Question 178

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

Answer 178

permit release of entrained vapour in the liquid.

Question 179

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

Answer 179

stress

Question 180

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

Answer 180

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

Question 181

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

Answer 181

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

Question 182

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

Answer 182

rupture diaphragm

Question 183

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

Answer 183

5 cms

Question 184

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

Answer 184

Foamy

Question 185

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

Answer 185

more than

Question 186

Hold up of material in a operating rotary drier is in the range of
0.05 to 0.15
0.25 to 0.50
0.5 to 0.8
0.8 to 0.9

Answer 186

0.05 to 0.15

Question 187

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

Answer 187

negative

Question 188

Flanges are connected to pipes by
screwing
welding
brazing
all (a), (b) and (c)

Answer 188

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

Question 189

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

Answer 189

0.5 to 1

Question 190

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

Answer 190

called tube clearance.

Question 191

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

Answer 191

Packed

Question 192

At equal mass velocities, the values of film co-efficients for gases as compared to that for liquids are generally:
higher
lower
same
unpredictable

Answer 192

lower

Question 193

The ratio of the largest load in a test to the original cross-sectional area of the test specimen is called the __________ stress.
yield point
breaking
ultimate
none of these

Answer 193

ultimate

Question 194

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

Answer 194

more than

Question 195

A ‘rupture disc’ is provided in chemical equipments as an accessory meant for ____.
relieving excess pressure.
creating turbulence.
enhancing mixing rate.
avoiding vortex formation.

Answer 195

relieving excess pressure.

Question 196

In a vertical short tube evaporator (Calendria type), the _____.
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.
area of central downtake is equal to 40 to 100% of total cross-sectional area of the surrounding tube.
liquor is inside the tube while the steam is outside the tube.
all (a), (b) & (c).

Answer 196

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

Question 197

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 _______.
U-bend
floating head tube sheet
either (a) or (b)
neither (a) nor (b)

Answer 197

either (a) or (b)

Question 198

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

Answer 198

called tube pitch.

Question 199

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

Answer 199

preventing the local overstressing of the shell around the opening.

Question 200

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

Answer 200

1.25

Question 201

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

Answer 201

2.5-3.0

Question 202

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

Answer 202

0 to 0.08

Question 203

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

Answer 203

l/15th

Question 204

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

Answer 204

cross-sectional area.

Question 205

The minimum baffle height should be _____.
equal to the impeller diameter.
twice the impeller diameter.
twice the tank diameter.
3/4 of the tank height.

Answer 205

twice the impeller diameter.

Question 206

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)
Di, opt = 3.9Q^0.45 ρ^0.13
Di, opt = 3.9Q^0.45 . μ^0.95
Di, opt = 4.7Q^0.36 . μ^3.2ρ^0.13
Di, opt = 3*Q^0.36 . μ^0.88

Answer 206

Di, opt = 3.9*Q^0.45 ρ^0.13

Question 207

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 ___.
0.5 d
d
1.5 d
2.5 d

Answer 207

1.5 d

Question 208

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

Answer 208

1-2

Question 209

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 ?
Segmental baffle
Flat plate extending across the wall
Disk type baffle
Helical type baffle

Answer 209

Flat plate extending across the wall

Question 210

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 ______.
only if the opening is on spherical vessel.
only if the opening is on a vertical cylinderical vessel.
only if the opening is on a horizontal cylinderical vessel.
irrespective of the shape of the vessel.

Answer 210

irrespective of the shape of the vessel.

Question 211

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

Answer 211

diamond

Question 212

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.
1 to 5
10 to 20
30 to 40
40 to 50

Answer 212

10 to 20

Question 213

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

Answer 213

about 3 times

Question 214

Pick out the wrong statement pertaining to the design of the distillation column.

Generally, a skirt clerance of 0.5” to 1.5’ is recommended to prevent plugging of the slots by residue build up.
The purpose of the slot is to disperse the gas into the liquid in the form of small bubbles.
If sufficient slot area is not provided, the gas may pass through the skirt clearance.
none of these.

Answer 214

none of these.

Question 215

The longitudinal stress induced in a thin walled cylinderical vessel under internal pressure is
pd/2t
pd/4t
pd/t
pd/8t

Answer 215

pd/4t

Question 216

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

Answer 216

least radius of gyration.

Question 217

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

Answer 217

3.8

Question 218

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.
2
1/2
4
1/4

Answer 218

4

Question 219

Hoop (circumferential) stress induced in a thin walled ‘Horton Sphere’ used for the storage of liquid ammonia under pressure is
pd/2t
pd/4t
pd/3t
pd/6t

Answer 219

pd/2t

Question 220

When one of the fluids is highly corrosive and has fouling tendency, it should _____.
preferably flow inside the tube for its easier internal cleaning.
perferably flow outside the tube.
flow at a very slow velocity.
flow outside the tube, when the flow is counter-current and inside the tube when the flow is co-current.

Answer 220

preferably flow inside the tube for its easier internal cleaning.

Question 221

The ratio (properller agitator dia/tank dia), is normally taken as
0.15-0.30
0.5-0.65
0.75-0.85
0.60-0.90

Answer 221

0.15-030

Question 222

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

Answer 222

elbow

Question 223

Maximum plate efficiency is achieved in case of __________ flow.
split
cross
cascade
reverse

Answer 223

cross

Question 224

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

Answer 224

ratio of true temperature difference to the LMTD.

Question 225

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.
equal to
half
one fourth
three fourth

Answer 225

one fourth

Question 226

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

Answer 226

0.25

Question 227

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
1.5-2.5
3.5-5.5
7.5-10.0
10-15

Answer 227

1.5-2.5

Question 228

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

Answer 228

complete back mixing.

Question 229

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
0.01
0.3
0.75
0.95

Answer 229

0.3

Question 230

Removable connection of tubes to tube sheet is called
ferrule
socket
nipple
saddle

Answer 230

ferrule

Question 231

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

Answer 231

0.5”

Question 232

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

Answer 232

either ‘a’ or ‘b’.

Question 233

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

Answer 233

0.6-0.8 times

Question 234

Le/D for couplings and unions would be
60
200
350
negligible

Answer 234

negligible

Question 235

What is the slope of the operating line in the rectifying section of a distillation coloumn ?
0
∞
> 1
<1

Answer 235

<1

Question 236

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

Answer 236

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

Question 237

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

Answer 237

18

Question 238

Joint efficiency (J) for a seamless pipe is
1
0.85
1.2
< 0.5

Answer 238

1

Question 239

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

Answer 239

allowable gas velocity through the slots.

Question 240

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

Answer 240

orifice

Question 241

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

Answer 241

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

Question 242

Back-trapping in a distillation column results due to ______.
low gas velocity.
high gas velocity.
excessive liquid gradient over the tray.
low reflux ratio.

Answer 242

excessive liquid gradient over the tray.

Question 243

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 ?
0.8
0.9
1.0
(0.8)0.5

Answer 243

0.8

Question 244

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

Answer 244

more

Question 245

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

Answer 245

15

Question 246

Lap joints are preferred for plates having thickness __________ mm.
< 12.5
> 3
> 5
5-10

Answer 246

> 3

Question 247

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

Answer 247

7.5

Question 248

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

Answer 248

10 metres

Question 249

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

Answer 249

both (a) & (b).

Question 250

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
1000
3000
5000
10000

Answer 250

10000

Question 251

Equivalent diameter for heat transfer calculation for a duct of square cross-section having each side as ‘d’ will be
d
√d
√2πd
√2d

Answer 251

d

Question 252

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

Answer 252

if its diameter is less than 15-20metres.

Question 253

For high pressure process equipments/vessels, the connected nozzle should be
welded
screwed
flanged
brazed

Answer 253

flanged

Question 254

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

Answer 254

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

Question 255

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

Answer 255

large diameter tanks.

Question 256

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 ?
hemispherical
ellipsoidal (2 : 1)
conical
flat plate

Answer 256

ellipsoidal (2 : 1)

Question 257

In inclined long tube vertical evaporators, the tubes are inclined at an angle of
15°
90°
45°
60°

Answer 257

45°

Question 258

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

Answer 258

1.1 to 1.5

Question 259

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

Answer 259

circumferential pipewall tension.

Question 260

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

is always less than arithmetic average value.
is always more than arithmetic mean value and the geometric mean value.
is always less than arithmetic mean value, but more than geometric mean value.
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 260

is always less than arithmetic average value.

Question 261

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

Answer 261

tall vertical

Question 262

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

Answer 262

high viscosity liquids (> 600 poise).

Question 263

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

Answer 263

increases

Question 264

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

Answer 264

50-75

Question 265

For pipe flows, head is proportional to __________ at constant capacity (where D = pipe diameter ).
1/D
1/D^2
1/D^5
D^2

Answer 265

1/D^5

Question 266

Friction factor for turbulent flow in a new pipe is given by
f = 16/N_re
f = 0.04/(N_re)^0.16
f = 0.22*N_re0.5
f = 25/N_re

Answer 266

f = 0.04/(N_re)^0.16

Question 267

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

Answer 267

6

Question 268

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

Answer 268

blue

Question 269

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
0.4-0.6
0.35-0.75
0.1-0.2
0.55-0.85

Answer 269

0.1-0.2

Question 270

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

Answer 270

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

Question 271

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

Answer 271

1/30th

Question 272

Longitundinal stress induced in a thin walled cylindrical storage vessel is
pD/2t
pD/4t
pD/3t
pD/6t

Answer 272

pD/4t

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.
shear
tensile
compressive
thermal

Answer 273

thermal

Question 274

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

Answer 274

25

Question 275

Pick out the wrong statement pertaining to a shell and tube heat exchanger.

The minimum value of baffle spacing is 50 mm.
The maximum value of baffle spacing is equal to the I.D. of the shell.
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.
Disk and doughnut baffle is the most commonly used baffle.

Answer 275

Disk and doughnut baffle is the most commonly used baffle.

Question 276

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

Answer 276

entrainment considerations.

Question 277

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

Answer 277

less

Question 278

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

Answer 278

0.4-0.9

Question 279

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

Answer 279

Smaller dia vessel.

Question 280

Reflux ratio variation in a distillation column is between
zero and infinity
zero and one
minimum and infinity
none of these

Answer 280

minimum and infinity

Question 281

Width and depth of grooves in the tube sheet holes normally are __________ inch respectively.
1/8 and 1/64
1/64 and 1/8
1/2 and 8
1/2 and 5

Answer 281

1/8 and 1/64

Question 282

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

Answer 282

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.
1/10-1/15th
1/5-1/10th
1/20-1/30th
1/2 to 1/4th

Answer 283

1/10-1/15th

Question 284

Height of the flights in the rotary drier is in the range of
0.08 to 0.12 d
0.02 to 0.05 d
0.2 to 0.5 d
0.5 to 0.6 d

Answer 284

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.
0.1 to 0.3
0.6 to 0.7
0.85 to 0.95
1.5 to 2

Answer 285

0.6 to 0.7

Question 286

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

Answer 286

floating

Question 287

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

Answer 287

both (a) & (b).

Question 288

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

Answer 288

none of these.

Question 289

Pick out the wrong statement.
In practical operation, distillation towers having diameter 3-6 metres equipped with bubble cap (round) size of 15 cms are used.
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.
In a seive tray, the minimum hole diameter is equal to the tray thickness.
In a stainless steel seive tray, the minimum hole diameter is equal to 10 times the plate thickness.

Answer 289

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

Question 289

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

Answer 289

5

Question 289

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

Answer 289

thrice

Question 289

Diameter of rivet hole (d, mm) and the plate thickness (t, mm) are related by Unwin’s formula as
d = 1.1 t
d = 1.6√t
d = 1.5 t
d = 3√t

Answer 289

d = 1.6√t

Question 290

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

Answer 290

positive

Question 291

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

Answer 291

Horizontal tube evaporator

Question 292

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
2
2^0.8
2^0.2
none of these

Answer 292

2^0.8

Question 293

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

Answer 293

creating turbulence.

Question 294

For turbine agitator, the impeller diameter is about
0.3 to 0.5 d
0.1 to 0.2 d
0.65 to 0.85 d
0.95 d

Answer 294

0.3 to 0.5 d

Question 295

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.

increase by 1.8
decrease by 2^2
increase by 2^1.6
none of these

Answer 295

increase by 2^1.6

Question 296

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

Tube dia is 3-6 cms, while tube length in 3-6 metres.
Steam is fed to the shell, whereas the liquor is filled inside the tube.
Liquor level is maintained at l/3rd to 1/2 of the height of the tube.
none of these.

Answer 296

none of these.

Question 297

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

Answer 297

25% cut segmental baffle.

Question 298

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

Answer 298

6.5 mm

Question 299

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

Answer 299

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

Question 300

Safety valves are provided in chemical equipments to guard against excessive
temperature
pressure/pressure fluctuation
turbulence
noise

Answer 300

pressure/pressure fluctuation

Question 301

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

Answer 301

not related with

Question 302

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

Answer 302

both (a) and (b).

Question 303

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
downcomer liquid seal
static submergence
skirt clearance
none of these

Answer 303

static submergence

Question 304

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

Answer 304

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

Question 305

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 ?
To increase the residence time of shell side fluid.
To provide support to the tube bundle.
To reduce the induced vibration in the tubes.
To increase the tube side heat transfer co-efficient by inducing turbulence.

Answer 305

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

Question 306

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.
45
60
80
95

Answer 306

80

Question 307

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

Answer 307

d

Question 308

Baffle width is normally taken as __________ times the tank diameter.
0.1-0.12
0.4-0.5
0.45-0.6
0.2-0.45

Answer 308

0.1-0.12

Question 309

A cylinderical pressure vessel of volume 6 πm3 has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm2 and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to
5 mm
6 mm
8 mm
10 mm

Answer 309

10 mm

Question 310

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

Answer 310

Cross-partition rings.

Question 311

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

Answer 311

High specific heat

Question 312

The equivalent diameter for fluid flow through a channel of constant non-circular cross section of area ‘A’ is given by (where, P = perimeter of the channel in contact with the fluid)
4A/P
A/P
4P/A
√A

Answer 312

4A/P

Question 313

Fouling factor must be included in the calculation of over all design heat transfer coefficient, when the liquid ______.
containing suspended solids flows at low velocity.
containing suspended solids flows at high velocity.
is highly viscous.
is of high specific gravity.

Answer 313

containing suspended solids flows at low velocity.

Question 314

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

Answer 314

small

Question 315

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.
CO2
SO2
NH3
none of these

Answer 315

NH3

Question 316

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

Answer 316

Triangular pitch.

Question 317

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

Answer 317

decreases

Question 318

Cylindrical pressure vessels in horizontal condition is generally supported on a __________ support.
lug
skirt
saddle
guy wire

Answer 318

saddle

Question 319

Pressure drop per tray in the atmospheric distillation column is about __________ psi.
0.01 - 0.5
0.07 - 0.12
0.5 - 1.0
1 - 3

Answer 319

0.07 - 0.12

Question 320

Welded joint efficiency in the design of chemical process equipment is taken as
0.55
0.75
0.85
0.95

Answer 320

0.85

Question 321

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

Answer 321

twice

Question 322

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
1
2
3
3.5

Answer 322

1

Question 323

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.
about 9
considerably more than 9
considerably less than 9
about 3

Answer 323

considerably more than 9

Question 324

The ratio of linear stress to linear strain is termed as the
modulus of elasticity
modulus of rigidity
bulk modulus
none of these

Answer 324

modulus of elasticity

Question 325

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

Answer 325

Ellipsoidal

Question 326

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

Answer 326

a finite stage contactor.

Question 327

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.
0.5 to 1.5
2.5 to 4.0
5 to 10
10 to 15

Answer 327

2.5 to 4.0

Question 328

Pick out the wrong statement.

Rivetting provides a permanent fastening method.
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’.
Shank diameter of the rivets should be less than the size of the hole drilled in the plate for rivetting.
The efficiency of a rivetted joint is the ratio of the strength of the rivetted joint to the strength of the solid plate.

Answer 328

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 329

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

Answer 329

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

Question 330

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

Answer 330

100

Question 331

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

Answer 331

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

Question 332

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

Answer 332

2

Question 333

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

Answer 333

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

Question 334

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

Answer 334

23

Question 335

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

Answer 335

total cost considerations (pumping cost plus fixed cost of the pipe).

Question 336

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

Answer 336

250 to 500

Question 337

Vertical storage vessels are never supported by __________ support.
bracket
saddle
skirt
lug

Answer 337

saddle

Question 338

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

Answer 338

more than that for fluid flow.

Question 339

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)
E
σ
σ/E
E/σ

Answer 339

σ/E

Question 340

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.
two
five
ten
twenty

Answer 340

two

Question 341

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

Answer 341

∞

Question 342

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

Answer 342

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

Question 343

Liquid gradient over a tray can be minimised by
providing a higher skirt clearance or a higher weir.
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.
using split flow, radial flow or cascade flow for column diameter large than 4 ft.
all (a), (b) and (c).

Answer 343

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

Question 344

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 ______.
are easier to clean.
are less prone to fouling.
can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less.
none of these.

Answer 344

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

Question 345

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

Answer 345

25 and 60

Question 346

__________ heat exchanger is also known as ‘hair pin type’ exchanger,
Double pipe
Finned
Plate type
Regenerative

Answer 346

Double pipe

Question 347

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

Answer 347

0

Question 348

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

Answer 348

1.5

Question 349

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

Answer 349

0.25 to 8

Question 350

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

Answer 350

6-8

Question 351

The ratio of lateral strain to linear strain is termed as the
Poisson’s ratio
bulk modulus
modulus of elasticity
shear modulus

Answer 351

Poisson’s ratio

Question 352

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

Answer 352

margin

Question 353

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

Answer 353

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

Question 354

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

Answer 354

38

Question 355

Pick out the wrong statement.
If sufficient residence time (around 8 seconds) is not proivided to the downcoming liquid in the downcomer, it may entrain some vapour.
The liquid head in the downcomer should not be greater than one half the plate spacing to avoid flooding.
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.
none of these.

Answer 355

none of these.

Question 356

Pick out the wrong statement pertaining to shell and tube heat exchanger.
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.
Baffles are supported independently of the tubes by tie rods and positioned by spacers.
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.
Bracket supports are used for horizontal shell, while saddle support is used for vertical shell.

Answer 356

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

Question 357

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

Answer 357

short (< 2 m) and housed indoor.

Question 358

Souders Brown equation given by, , is used for the calculation of the __________ in a continuous distillation column.
diameter of the bubble cap column
diameter of the seive plate column
tray pressure drop
residence time in the downcomer for the disengagement of entrained vapour

Answer 358

diameter of the bubble cap column

Question 359

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
1
< 1
>1
equal to the order of reaction

Answer 359

> 1

Question 360

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

Answer 360

60

Question 361

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

Answer 361

less than arithmetic mean value.

Question 362

Practical dividing line between a ductile and brittle materials is suggested, when the ultimate elongation is about 5%. Generally, larger the knuckle radius, stronger is the corner torus section of a head. The knuckle radius provided should be less than __________ of the head.
6% of I.D.
3 times the thickness
either (a) or (b), whichever is larger
either (a) or (b), whichever is smaller

Answer 362

either (a) or (b), whichever is larger

Question 363

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”).
half
three fourth
equal to
1.5 times

Answer 363

equal to

Question 364

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
bending
deformation
shear
elongation

Answer 364

bending

Question 365

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

Answer 365

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

Question 366

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

Answer 366

Conical or flat plate

Question 367

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

Answer 367

Murphree plate efficiency.