chemical engineering MCQs – Page 185

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 Review each marked answer and report any item that may be outdated or unclear.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

3681. Normally, the length to diameter ratio of rotary dryers varies from 4 to 10 and for its economic operation; the number of transfer units (NTU) for such dryers varies from ?
0

A. 3.5-5.5

B. 1.5-2.5

C. 7.5-10.0

D. 15-Oct

3682. Maximum allowable vapour velocity in a bubble cap tower is determined by the ____________________?
0

A. None of these

B. Diameter of the column

C. Entrainment considerations

D. Vapour density

3683. The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is___________________?
0

A. 0

B. Minimum

C. 1

D. ?

3684. For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between ______________________ times the tank diameter?
0

A. 2.5 to 3.5

B. 1 to 1.5

C. 4 to 5

D. 6 to 8

3685. In a distillation column, the minimum residence time for liquid in the downspout is about ______________ seconds?
0

A. 80

B. 8

C. 180

D. 1

3686. In the design of a bag filter, the gas temperature is an important consideration, as it affects the___________________?
0

A. Gas viscosity

B. Fibre selection

C. All A., B. & C.

D. Gas density

3687. For given number of passes, pitch & tube diameter, the maximum number of tubes that can be accommodated in a shell of tripled inside diameter will be ____________ times?
0

A. About 9

B. Considerably less than 9

C. About 3

D. Considerably more than 9

3688. Vertical condenser is advantageous to the horizontal condenser from operation point of view, when________________?
0

A. Hydrostatic head is required for refluxing the condensate

B. Only the function of condensation is to be carried out

C. Sub-cooling of condensate is desired

D. Both the functions of condensation & sub cooling are carried out in a single unit

3689. 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____________________?
0

A. Increases

B. Decreases

C. May increase or decrease depending upon the solubility of the gas in the liquid

D. Remain same

3690. Generally, no corrosion allowance in wall thickness of a part is required, if the thickness is more than ______________ mm?
0

A. 30

B. 5

C. 10

D. 20

3691. A/an _______________ is used for changing the direction of a pipeline?
0

A. Disc compensator

B. Elbow

C. Flange

D. Union

3692. In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer coefficient (hi) vanishes after a Reynold number of_____________?
0

A. 10000

B. 3000

C. 1000

D. 5000

3693. Which of the following is not a graphical method (but is an analytical method) for the calculation of theoretical number of stages in case of continuous binary distillation ?
0

A. McCabe-Thieles method

B. None of these

C. Ponchon-Savarit method

D. Sorel-Lewis method

3694. A pipe is generally made of circular cross-section, because a circular cross-section has the____________________?
0

A. Higher structural strength

B. Lowest surface area requirement for a given volume

C. Both A. & B.

D. None of these

3695. Removable connection of tubes to tube sheet is called___________________?
0

A. Nipple

B. Ferrule

C. Saddle

D. Socket

3696. In a shell and tube heat exchanger having triangular pitch, the shell side equivalent diameter is given by________________?
0

A. (4P2 + ?d2/4)/?d

B. (P2 ?d2/4)/?d

C. 4(0.86P2 ?d2/4)/?d

D. 4(0.86P2 ?d2)/?d

3697. It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than _________________?
0

A. 0.55

B. 0.80

C. 0.95

D. 0.99

3698. Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger________________?
0

A. Permits the use of less tubes in a given shell diameter

B. Facilitates comparatively easier external cleaning because of large clearance

C. Permits the use of more tubes in a given shell diameter

D. Both B. and C.

3699. Heat transfer co-efficient for a horizontal condenser as compared to a vertical condenser operating under similar conditions is_______________?
0

A. Same

B. About 3 times

C. Less

D. About 0.33 times

3700. Fouling factor must be included in the calculation of overall design heat transfer coefficient, when the liquid__________________?
0

A. Is of high specific gravity

B. Containing suspended solids flows at high velocity

C. Is highly viscous

D. Containing suspended solids flows at low velocity

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