Section 1

Question 1

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

sea green
brown
yellow
red

Answer 1

sea green

Question 2

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

Rimmed steel
Mild steel
Killed steel
Semi-killed steel

Answer 2

Rimmed steel

Question 3

The ratio of shear stress to shear strain is called

bulk modulus
shear modulus
modulus of rigidity
modulus of elasticity

Answer 3

shear modulus

Question 4

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 4

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

Question 5

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

20
30
45
85

Answer 5

45

Question 6

Le/D for fully open globe value may be around

10
25
75
300

Answer 6

300

Question 7

Lug support is

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

Answer 7

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

Question 8

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

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

Answer 8

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

Question 9

With increase in the number of shell passes, the value of F subT

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

Answer 9

increases

Question 10

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 10

2.5 to 5

Question 11

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

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

Answer 11

5-11

Question 12

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

ultimate stress
yield stress
elastic limit
breaking stress

Answer 12

elastic limit

Question 13

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 13

shortest centre to centre distance between adjacent tubes.

Question 14

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

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 14

Reflux is not a saturated liquid.

Question 15

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 = 24.6 (Δp/μ)
η = 1.66 - 0.25 log μ
η = 0.25 log μ - 1.67

Answer 15

η = 17 - 61.1 log μ

Question 16

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 16

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

Question 17

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 17

10

Question 18

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 18

8

Question 19

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 19

(1.2)^5/3

Question 20

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 20

both (a) & (b)

Question 21

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 21

At the inner surface.

Question 22

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 22

0.80

Question 23

A rivetted joint does not fail by __________ of rivets.

tearing
shearing
tearing of the plate across a row
none of these

Answer 23

none of these

Question 24

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

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

Answer 24

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

Question 25

Bracket supports are the most suitable for supporting __________ vessels.

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

Answer 25

thick walled vertical

Question 26

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 26

none of these

Question 27

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 27

inside diameter

Question 28

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 28

7500

Question 29

Pick out the wrong statement

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

Answer 29

both (b) and (c).

Question 30

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 30

20

Question 31

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

20°
40°
60°
80°

Answer 31

60°

Question 32

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 32

75

Question 33

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 33

less

Question 34

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 34

ultimate stress to working stress.

Question 35

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 35

20-40

Question 36

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

Radial flow
Cross flow
Split flow
Cascade

Answer 36

Cross flow

Question 37

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

0
<1
1
>1

Answer 37

1

Question 38

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 38

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

Question 39

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 39

facilitate handling of large flow rate of liquid.

Question 40

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

50-150
5-10
500-1500
1500-2500

Answer 40

50-150

Question 41

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 41

Ellipsoidal

Question 42

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 Q0.^36 . ρ^1.86 μ^0.08

Answer 42

Di, opt = 3 Q^0.36 ρ^0.18

Question 43

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 43

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

Question 44

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 44

less

Question 45

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 45

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

Question 46

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 46

none of these.

Question 47

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 47

0.1 to 2

Question 48

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 48

prevention of fluid leakage around moving parts.

Question 49

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 49

Δp = G^2

Question 50

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 50

dished bottom vessel has very high power consumption.