chemical engineering MCQs – Page 180

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs

3581. Friction factor for turbulent flow in a new pipe is given by____________________?
0

B. f = 16/NRe

C. f = 0.04/(NRe)0.16

D. f = 0.22 NRe

E. f = 25/NRe

3582. In a rotary drier, the average retention time of solid is (where Z = length of the drier, metres ? = apparent solid density, kg/m3 L = flow rate of dry solids, kg/see. m2 drier crosssection H = hold up of solid.) ?
0

A. Z.H.?/L

B. Z.H/?L

C. L/Z.H.?

D. H.?/L

3583. The stress developed in a material without any permanent set is called the____________________?
0

A. Elastic limit

B. Yield stress

C. Breaking stress

D. Ultimate stress

3584. A riveted joint does not fail by _____________________ of rivets?
0

A. Tearing

B. Shearing

C. None of these

D. Tearing of the plate across a row

3585. In packed absorption tower, onset of flooding usually occurs at a pressure drop of about ______________ mm of water column per metre height of packing?
0

A. 25-50

B. 750-1000

C. 50-75

D. 200-250

3586. A pressure vessel is said to be made of thick shell, if the ratio of its diameter to wall thickness is_______________?
0

A. > 20

B. < 10

C. < 20

D. > 10

3587. The most common standard size of bubble caps used in industrial operation is___________________?
0

A. 1? dia cap with 0.5? dia riser

B. 8? dia cap with 1? dia riser

C. 4? dia cap with 8? dia riser

D. 6? dia cap with 4? dia riser

3588. Vapor velocity in a distillation column for non-foaming mixture is in the range of ______________ times the flooding velocity?
0

A. 1.5 to 2

B. 0.6 to 0.7

C. 0.85 to 0.95

D. 0.1 to 0.3

3589. The retention time of material in a rotary dryer depends upon its ______________________?
0

A. All A., B. and C.

B. Flights arrangement

C. Slope & length

D. rpm

3590. In a distillation column, minimum clearance to be maintained between the overflow weir and the last row of the bubble caps is ______________ cms?
0

A. 20

B. 15

C. 7.5

D. 2.5

3591. The units of Youngs modulus of elasticity and ________________ are the same?
0

A. Strain

B. None of these

C. Stress

D. Modular ratio

3592. Baffles are provided in a shell and tube heat exchanger to increase the turbulence and velocity of the shell side fluid. Which of the following shaped baffles does not fall in the category of transverse baffle ?
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A. Disk type baffle

B. Helical type baffle

C. Segmental baffle

D. Flat plate extending across the wall

3593. Overall tray efficiency of a distillation column is the ratio of the number of ___________________?
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A. Ideal trays required to the number of real trays required

B. Overall gas transfer units to the number of ideal trays required

C. Real trays required to the number of ideal trays required

D. None of these

3594. The thermal stress in a metallic bar does not depend upon the_____________________?
0

A. Changes in temperature

B. Cross-sectional area

C. Both A. and B.

D. Neither A. nor B.

3595. Longitudinal stress induced in a thin walled cylindrical storage vessel is __________________?
0

A. pD/3t

B. pD/6t

C. pD/4t

D. pD/2t

3596. In packed towers provided with saddle packing, liquid redistributors are positioned at every _______________ times column diameter or 6 metres whichever is less?
0

A. 5-8

B. 20-25

C. 3-Feb

D. 15-Oct

3597. 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_________________?
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A. None of these

B. Smaller reactor should come first

C. Larger reactor should come first

D. Equal sized reactors are the best

3598. The operating pressure drop range in a bag filter is about ______________ mm water gauge?
0

A. 1500-2500

B. 50-150

C. 500-1500

D. 10-May

3599. The necessary wall thickness for a metallic storage vessel is a function of the ___________________?
0

A. Ultimate tensile strength (or yield point) of the material and operating temperature

B. Diameter of the vessel

C. Operating pressure and welding/joint efficiency

D. All A., B. and C.

3600. For a cylindrical internally pressurised vessel, which of the following closure types would withstand highest pressure, if each closure is of the same material and thickness ?
0

A. Ellipsoidal (2 : 1)

B. Hemispherical

C. Flat plate

D. Conical

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