Q.1

__________ tower is the most suitable gas-liquid contacting device involving highly corrosive fluids.

  • Sieve plate
  • Packed
  • Bubble cap plate
  • None of these
Q.2

Pressure drop due to pipe fittings can be estimated by the equation,
, 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 (dimensionless) forelbow andclose return bends would be respectively around

  • 5 and 10
  • 45 and 75
  • 180 and 300
  • 300 and 500
Q.3

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
Q.4

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

  • 6
  • 18
  • 24
  • 34
Q.5

Maximum allowable vapour velocity in a bubble cap tower is determined by the

  • entrainment considerations.
  • vapour density.
  • diameter of the column.
  • none of these.
Q.6

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
Q.7

Normally, the length to diameter ratio of rotary dryers varies form 4 toand 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
Q.8

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
Q.9

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
Q.10

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
Q.11

At equal mass velocities, the values of film co-efficients for gases as compared to that for liquids are generally.

  • higher
  • lower
  • same
  • unpredictable
Q.12

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.
Q.13

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
Q.14

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
Q.15

Oxygen carrying pipelines in chemical industries are coloured with __________ colour.

  • yellow
  • black
  • blue
  • red
Q.16

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
Q.17

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.
Q.18

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
Q.19

The normal range of velocity of water in pipes is __________ m/sec.

  • 0.1-0.5
  • 1-2
  • 10-50
  • 15-30
Q.20

Seamless pipe is made

  • from rolled strips formed into cylinders and seam-welded.
  • by extrusion & casting into static and centrifugal molds.
  • by forging a solid round, piercing it by simultaneously rotating & forcing it over a piercer point and further reducing it by rolling gas drawing.
  • both (b) and (c).
Q.21

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
Q.22

Baffles may be eliminated for

  • low viscosity liquids (< 200 poise).
  • high viscosity liquids (> 600 poise).
  • large diameter tanks.
  • none of these.
Q.23

For high pressure process equipments/vessels, the connected nozzle should be

  • welded
  • screwed
  • flanged
  • brazed
Q.24

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

  • 15°
  • 90°
  • 45°
  • 60°
Q.25

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

  • 1
  • 5
  • 15
  • 25
Q.26

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

  • 6
  • 12
  • 18
  • 34
Q.27

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
Q.28

The equivalent diameter for pressure drop is __________ that for heat transfer.

  • smaller than
  • greater than
  • equal to
  • not related with
Q.29

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.
Q.30

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.
Q.31

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
Q.32

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.
Q.33

Bubble cap plate column is

  • a finite stage contactor.
  • used only for distillation, not for absorption.
  • a differential stage contactor.
  • a continuous contactor.
Q.34

Baffle spacing is generally __________ the I.D. of the shell.

  • more than
  • not greater than
  • not less than one fifth of
  • both (b) and (c)
Q.35

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
Q.36

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.
Q.37

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
Q.38

The thickness of segmental baffles (-cut truncated plates usually) is generally __________ the tube wall thickness.

  • equal to
  • twice
  • four times
  • half
Q.39

__________ of water makes it a widely used coolant in heat exchangers.

  • Low corrosiveness
  • Low dirt factor
  • High specific heat
  • Low viscosity
Q.40

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.
Q.41

Joint efficiency (J) for a seamless pipe is

  • 1
  • 0.85
  • 1.2
  • < 0.5
Q.42

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

  • 0.5 d
  • 0.75 d
  • d
  • 2 d
Q.43

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).
Q.44

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
Q.45

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
Q.46

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.
Q.47

In packed towers provided with pall rings liquid redistributors are positioned at heights of every 6 metres or 5-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
Q.48

In seive plate column, holes are drilled or punched in sizes ranging from 2.5 tomm (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
Q.49

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.
Q.50

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.
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