Q.1

__________ liquor is best handled in a long tube vertical evaporator.

  • Foamy
  • Scaling
  • Viscous
  • Salting
Q.2

__________ shaped roof is most commonly used for cylindrical tanks.

  • Cone
  • Dome
  • Umbrella
  • Flat
Q.3

Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to

  • G0.2
  • G0.5
  • G0.8
  • G1.5
Q.4

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
Q.5

Nominal size of a pipe is an indication of its __________ diameter.

  • inner
  • outer
  • approximate
  • none of these
Q.6

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
Q.7

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.
Q.8

A forced circulation long tube vertical evaporator as compared to the natural circulation evaporator

  • is economical in operation.
  • employs high velocity, high heat transfer rate and less heating surface requirement.
  • employs a centrifugal pump placed between external downtake from vapor drum and inlet to tube bundle.
  • both (b) & (c).
Q.9

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.
Q.10

__________ dished head is the strongest of all.

  • Hemispherical
  • Elliptical
  • Torispherical
  • none of these
Q.11

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

  • D2
  • D5
  • D
  • D9
Q.12

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)
Q.13

In a thin cylindrical shell, the hoop stress is __________ stress.

  • radial
  • circumferential tensile
  • compressive
  • longitudinal
Q.14

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

  • half
  • equal to
  • twice
  • eight times
Q.15

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).
Q.16

Apex angle of conical heads used in the bottom heads of chemical process equipments is usually

  • 30°
  • 45°
  • 60°
  • 75°
Q.17

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
Q.18

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
Q.19

The dust collection efficiency of electrostatic precipitator increases with increase in the

  • gas flow rate.
  • electrode area.
  • both (a) & (b).
  • neither (a) nor (b).
Q.20

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
Q.21

Back-trapping in a distillation column results due to

  • low gas velocity.
  • high gas velocity.
  • excessive liquid gradient over the tray.
  • low reflux ratio.
Q.22

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.
Q.23

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
Q.24

For a cylinderical vessel of moderate height, the weld joint efficiency for joints parallel to the cylinderical axis is given as 1.while for joints along the girth (circumference) it is given as 0.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
Q.25

The longitudinal stress induced in a thin walled cylinderical vessel under internal pressure is

  • pd/2t
  • pd/4t
  • pd/t
  • pd/8t
Q.26

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'.
Q.27

Value of Peclet number =is the representative of

  • laminar flow.
  • complete back mixing.
  • plug flow.
  • eddy diffusivity = 0.
Q.28

Maximum plate efficiency is achieved in case of __________ flow.

  • split
  • cross
  • cascade
  • reverse
Q.29

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

Q.30

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
Q.31

In distillation columns, bubble caps are held in place over trays by

  • rivets
  • a hold down bar
  • bolts
  • both (b) and (c)
Q.32

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)
Q.33

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.)

Q.34

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
Q.35

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.
Q.36

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
Q.37

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.
Q.38

What is the slope of the operating line in the rectifying section of a distillation coloumn ?

  • 0
  • > 1
  • <1
Q.39

Removable connection of tubes to tube sheet is called

  • ferrule
  • socket
  • nipple
  • saddle
Q.40

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
Q.41

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).
Q.42

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
Q.43

Lap joints are preferred for plates having thickness __________ mm.

  • < 12.5
  • > 3
  • > 5
  • 5-10
Q.44

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

  • 1.2
  • 0.5
  • 3.8
  • 6.8
Q.45

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).
Q.46

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
Q.47

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).
Q.48

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.
Q.49

For turbulent flow (NRe >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 = 3.9 Q0.45 ρ0.13
  • Di, opt = 3.9 Q0.45 . μ0.95
  • Di, opt = 4.7 Q0.36 . μ3.2ρ0.13
  • Di, opt = 3 Q0.36 . μ0.88
Q.50

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
0 h : 0 m : 1 s