Practice Pakistan's most useful MCQs for competitive exams

Souders Brown equation given by, U = Kv √(ρl – ρv)/ρv, is used for the calculation of the ______________ in a continuous distillation column?

• (A)  Diameter of the bubble cap column
• (B)  Diameter of the sieve plate column
• (C)  Tray pressure drop
• (D)  Residence time in the downcomer for the disengagement of entrained vapour

Answer

Submitted By :Ali Uppal

Pressure differential maintained across a continuous rotary vacuum filter is in the range of _______________ mm Hg column?

• (A)  50 to 100
• (B)  100 to 150
• (C)  250 to 500
• (D)  600 to 700

Answer

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The wall thickness of thin cylindrical shell with hemispherical ends is ______________ that of the spherical ends?

• (A)  Equal to
• (B)  More than
• (C)  Less than
• (D)  Either

Answer

Submitted By :Ali Uppal

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____________________?

• (A)  ∞
• (B)  1
• (C)  20.8
• (D)  2

Answer

Submitted By :Ali Uppal

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____________________?

• (A)  Only if the opening is on spherical vessel
• (B)  Only if the opening is on a vertical cylindrical vessel
• (C)  Only if the opening is on a horizontal cylindrical vessel
• (D)  Irrespective of the shape of the vessel

Answer

Submitted By :Ali Uppal

(Le/D) for couplings and unions would be_______________?

• (A)  60
• (B)  200
• (C)  350
• (D)  Negligible

Answer

Submitted By :Ali Uppal

Ratio of tube length to shell diameter for a shell and tube heat exchanger is________________?

• (A)  8 : 1 to 12 : 1 for both liquid-liquid and gas-gas heat exchangers
• (B)  4 : 1 to 8 : 1 for liquid-liquid exchanger
• (C)  < 4 : 1 for gas-gas exchangers
• (D)  Both

Answer

Submitted By :Ali Uppal

Liquid gradient over a tray can be minimised by________________?

• (A)  Providing a higher skirt clearance or a higher weir
• (B)  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
• (C)  Using split flow, radial flow or cascade flow for column diameter large than 4 ft
• (D)  All

Answer

Submitted By :Ali Uppal

Slope of counter-current flow rotary drier is in the range of ____________ meter/metre?

• (A)  0 to 0.08
• (B)  0 to 0.8
• (C)  0 to 1.5
• (D)  0 to 2.2

Answer

Submitted By :Ali Uppal

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?

• (A)  nth
• (B)  (1/n)th
• (C)  0.5 nth
• (D)  1.5 nth

Answer

Submitted By :Ali Uppal