chemical engineering process equipment and plant design MCQs – Page 8

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering process equipment and plant design Mcqs
141. Heat transfer co-efficient, hG(Kcal/hr.m2 .C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to ____________________?
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A. hG = 1.004G0.37

B. 1.004G0.8

C. hG = 0.0176G0.37

D. 0.0176G1.37

142. Generally, elliptical dished heads____________________?
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B. ll of the same thickness and diameter

C. Resist half the pressure rating compared to hemi spherical head provided on the cylindrical

D. Are approximately as strong as seamless cylindrical shell having the corresponding I.D and

E. Are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for

F. ssure vessels operating above a pressure of 1.5 MN/m2

143. For a cylindrical vessel of moderate height, the weld joint efficiency for joints parallel to the cylindrical axis is given as 1.0; while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylindrical vessel, what value of weld joint efficiency should be used ?
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A. 0.8

B. (0.8)0.5

C. 1

D. 0.9

144. Larger depth of liquid on the trays of a distillation column_________________?
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A. Leads to high tray efficiency

B. Results in higher pressure drop per tray

C. Both A. & B.

D. Neither A. or B.

145. Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the_______________?
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A. Flow rates of each fluid

B. Concentration of each fluid

C. All A, B. & C.

D. Type and size of packing

146. The equivalent diameter for fluid flow through a channel of constant non-circular cross section of area A is given by (where, P = perimeter of the channel in contact with the fluid) ?
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A. ?A

B. 4 P/A

C. A/P

D. 4 A/P
147. Maximum allowable vapour velocity in a bubble cap tower is determined by the ____________________?
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A. None of these

B. Vapour density

C. Entrainment considerations

D. Diameter of the column

148. Hole diameter of the sieve trays in the distillation column ranges from ______________ mm?
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A. 3 to 12.5

B. 1 to3

C. 4 to 8

D. 12.5 to 18.5

149. It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than _________________?
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A. 0.95

B. 0.80

C. 0.99

D. 0.55

150. In packed absorption tower, onset of flooding usually occurs at a pressure drop of about ______________ mm of water column per metre height of packing?
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A. 50-75

B. 750-1000

C. 25-50

D. 200-250

151. Generally, as the length of the liquid path on a tray is increased beyond 5 ft, the overall column efficiency___________________?
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A. Decreases

B. Remain same

C. May increase or decrease depending upon the plate spacing

D. Increases
152. In a shell and tube heat exchanger, tube side _______________ of the mass velocity?
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A. Heat transfer co-efficient is proportional to 0.8th power

B. Pressure drop is proportional to the square

C. Both A. & B.

D. Neither A. nor B.

153. What is the slope of the operating line in the stripping section of a distillation column ?
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A. 0

B. < 1

C. ?

D. > 1
154. In a heat exchanger, shell side fluid velocity can be changed by changing the tube _______________________?
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A. Layout

B. Pitch

C. Both A. & B.

D. Neither A. nor B.

155. In a thin cylindrical shell, the hoop stress is ________________ stress?
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A. Circumferential tensile

B. Longitudinal

C. Compressive

D. Radial

156. Floating head heat exchangers are used for the____________________?
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A. Co-current heat transfer systems

B. Cases where temperature difference between the shell and the tubes is more (>50C)

C. Counter-current heat transfer systems

D. Heat transfer between corrosive fluids

157. The difficulty of liquid distribution in packed towers is accentuated, when the ratio of tower diameter to packing diameter is_________________?
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A. < 7

B. > 7 20 < 50

C. < 30

158. In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of ________________ mm?
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A. 5-Mar

B. 18-Dec

C. 15-Aug

D. 5-11
159. In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube ?
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A. Short tube vertical evaporator

B. None of these

C. Long tube vertical evaporator

D. Horizontal tube evaporator
160. If a single tube pass heat exchanger is converted to two passes; for the same flow rate, the pressure drop per unit length in tube side will _____________ times?
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A. Decrease by 22

B. None of these

C. Increase by 21.6

D. Increase by 1.8