Practice Process Equipment And Plant Design Multiple Choice Questions with Answers Quiz-9

Q.1.

__________ closure is the weakest enclosure for cylindrical vessels.

Hemispherical
Torispherical
Conical or flat plate
Elliptical

Q.2.

Thickness of the frame of a plate and frame filter as compared to that of plates is

less
same
more
either (a) or (b)

Q.3.

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).

Q.4.

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)

Q.5.

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

Q.6.

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

Q.7.

Vertical vessels are not supported by

brackets
skirts
columns
saddles

Q.8.

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.

Q.9.

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

Q.10.

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).

Q.11.

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

19
38
76
95

Q.12.

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).

Q.13.

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.

Q.14.

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

10
20
30
5

Q.15.

Which of the following efficiencies can be greater than?

Overall plate efficiency.
Murphree plate efficiency.
Point efficiency.
None of these.

Q.16.

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).

Q.17.

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

Q.18.

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.

Q.19.

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.

Q.20.

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.

Q.21.

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.

Q.22.

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 thanmm (7/8").

half
three fourth
equal to
1.5 times

Q.23.

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)

Q.24.

In a __________ rivetted joint, the number of rivets decreases from the innermost row to the outermost row.

chain
diamond
zig-zag
none of these

Q.25.

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.

Q.26.

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

Q.27.

Rivets are generally specified by the

head diameter
shank diameter
overall length
none of these

Q.28.

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'.

Q.29.

The circumferential (hoop) stress in a thin walled cylinderical vessel under internal pressure is

pd/2t
pd/4t
pd/t
pd/3t

Q.30.

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.

Q.31.

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

Q.32.

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.

Q.33.

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.

Q.34.

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

Q.35.

A/an __________ is used for changing the direction of a pipeline.

elbow
union
flange
disc compensator

Q.36.

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

Q.37.

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 thanmm (7/8").

half
three fourth
equal to
1.5 times

Q.38.

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

zig-zag
chain
diamond
none of these

Q.39.

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

Q.40.

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.

Q.41.

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.

Q.42.

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

Q.43.

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

Q.44.

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.

Q.45.

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

Q.46.

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

Q.47.

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.

Q.48.

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'

Q.49.

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.

Q.50.

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.

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