chemical engineering process equipment and plant design Mcqs
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

161. In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area) ?
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A. Sa = 1.5 Aa

B. Aa = Sa

C. Aa = 1.5 Sa

D. 1.2 Aa = 1.2 Sa

162. Most of the storage vessels/tanks are made cylindrical, because of the fact that a cylinder _________________?
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A. Has greater structural strength

B. Is easy to fabricate

C. Both A. and B.

D. Neither A. nor B.

163. The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is___________________?
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A. 1

B. Minimum

C. ?

D. 0

164. The thickness of heat transfer plates used in the plate type heat exchanger ranges from _____________ mm, pressed in a single piece provided with grooves & corrugations?
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A. 1.25 to 3.125

B. 3.5 to 7.0

C. 8 to12

D. 0.3 to 0.8

165. The wall thickness for a large high pressure pipeline is determined by the consideration of the____________________?
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A. Circumferential pipe-wall tension

B. Forces exerted by static and dynamic action at bends

C. Temperature stresses

D. Axial tensile stress in the pipe

166. ____________ is the determining factor for the number of bubble caps to be used per tray?
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A. Permissible slot velocity

B. Vapor load

C. Tray diameter

D. Liquid load

167. Vapor velocity in a distillation column for non-foaming mixture is in the range of ______________ times the flooding velocity?
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A. 0.85 to 0.95

B. 1.5 to 2

C. 0.1 to 0.3

D. 0.6 to 0.7
168. Safety valves are provided in chemical equipments to guard against excessive_________________?
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A. Turbulence

B. Pressure/pressure fluctuation

C. Noise

D. Temperature

169. In condenser, the cooling water is passed in the tube side in a pass arrangement, because________________?
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A. It makes condenser compact

B. More thinner tubes can be used

C. Pressure drop is reduced

D. It reduces heat transfer area
170. A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of_________________?
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A. 20.8

B. None of these

C. 20.2

D. 2

171. Which tube arrangement in a heat exchanger would facilitate highest heat transfer rate ?
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A. Heat transfer rate is independent of tube arrangement

B. Square pitch

C. Diagonal square pitch

D. Triangular pitch
172. 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_____________?
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A. 1000

B. 3000

C. 5000

D. 10000
173. An adequate clearance between the tray and the shell wall of a distillation column is provided to_____________________?
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A. Allow for thermal expansion and facilitate installation

B. Avoid back-trapping

C. None of these

D. Drain the liquid from the tray when the unit is not in operation

174. Pick out the wrong statement pertaining to the comparative evaluation of performance of the packed tower and the plate tower ?
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A. persed solids

B. igned for the same duty</strong>

C. ferred over packed towers as the packing may be crushed due to large temperature changes

D. The total weight of a dry plate tower is usually much more than that of a dry packed tower

E. In operations involving large temperature changes. (e.g. distillation), plate towers are

F. Plate tower is preferred over packed tower, if the operation involves liquids containing

175. The safe distance of habitation from a hazardous chemical plant (TLV of its product < 1000 ppm) should be about ______________ kms?
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A. 15

B. 1

C. 25

D. 5

176. Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to___________________?
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A. G0.5

B. G0.2

C. G1.5

D. G0.8
177. Shell side heat transfer co-efficient in case of square pitch as compared to the triangular pitch under similar condition of fluid flow and tube size is_____________?
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A. More

B. Same

C. Less

D. Twice

178. Cylindrical storage tanks used for the storage of volatile liquids (e.g., naphtha) have ______________ roofs?
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A. Fixed

B. Conical

C. Floating

D. Flat

179. In case of 1.5? heat exchanger tubes, the inside flow area _____________ with decrease in BWG?
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A. Increases

B. None of these

C. Remains same

D. Decreases
180. ______________ of water makes it a widely used coolant in heat exchangers?
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A. Low dirt factor

B. High specific heat

C. Low viscosity

D. Low corrosiveness

181. The ratio of volumes of the mixed reactor to the plug flow reactor (for identical feed composition, flow rate, conversion, and for all positive reaction orders) is always ?
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A. Equal to the order of reaction

B. < 1

C. 1

D. > 1
182. The dust collection efficiency of electrostatic precipitator increases with increase in the_________________?
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A. Gas flow rate

B. Electrode area

C. Both A. & B.

D. Neither A. nor B.

183. In a shell and tube heat exchanger having triangular pitch, the shell side equivalent diameter is given by________________?
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A. (P2 ?d2/4)/?d

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

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

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

184. Smokers equation for the calculation of number of equilibrium stages in a continuous binary distillation column is used, when the_________________?
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A. Relative volatility is close to one (e.g., separation of close boiling isomers)

B. Number of equilibrium stages in only stripping section is to be calculated

C. Number of equilibrium stages required is likely to be very small

D. Feed is not at its bubble point

185. The diameter of a propeller agitator used in agitation tank ranges from ____________ percent of the tank diameter and its peripheral speed is normally 300 to 500 metres/minute ?
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A. 5 to 10

B. 15 to 30

C. 40 to 50

D. 55 to 75

186. The absorption factor is defined as (where, S1 = slope of the equilibrium curve, S2 = slope of the operating line) ?
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A. S1.S2

B. 1/S1.S2

C. S2/S1

D. S1/S2
187. The thickness of segmental baffles (25 -35% cut truncated plates usually) is generally _____________ the tube wall thickness?
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A. Equal to

B. Four times

C. Twice

D. Half

188. Back-trapping in a distillation column results due to_________________?
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A. High gas velocity

B. Low gas velocity

C. Excessive liquid gradient over the tray

D. Low reflux ratio

189. For laminar flow (NRe < 2100) in steel pipe, the optimum inside pipe diameter is given by____________________?
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A. Di, opt = 3 Q0.36 ?1.86 ?0.08

B. Di, opt = 3.9 Q0.45 ?0.23

C. Di, opt = 3 Q0.36 ?0.18

D. Di, opt = 7.6 Q0.36 ?0.9

190. ____________________ strain is measured using a strain rosetter ?
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A. Shear

B. None of these

C. Linear

D. Volumetric

191. With increase in the reflux ratio for a fixed production from a continuous binary distillation column, the ______________________ decreases?
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A. Fixed charges initially

B. Running cost of cooling water for condenser

C. Vapour & liquid load both

D. Running cost of steam for reboiler

192. In the downcomer of a distillation column, the minimum recommended residence time is about _______________ seconds?
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A. 17.5

B. 12.5

C. 2.5

D. 5
193. A pressure vessel is said to be made of thick shell, if the ratio of its diameter to wall thickness is_______________?
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A. > 10

B. < 20

C. < 10

D. > 20

194. Rotary driers are most economically designed for the number of heat transfer units (HTU) from _________________?
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A. 5 to 10

B. 1.5 to 2.5

C. 0.01 to 1

D. 10 to 20

195. A claming section before the liquid flows into the downcomer is provided to__________________?
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A. Cool the liquid before it flows down

B. Ensure better vapour-liquid contact

C. Permit release of entrained vapour in the liquid

D. Reduce the discharge fluctuation

196. Generally, no corrosion allowance in wall thickness of a part is required, if the thickness is more than ______________ mm?
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A. 10

B. 5

C. 20

D. 30
197. A binary liquid Azeotropic mixture has boiling point higher than either of the components, when it shows ______________ deviation from Raoults Law?
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A. Negative

B. No

C. None of these

D. Positive

198. The equivalent diameter for pressure drop is _______________ that for heat transfer?
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A. Not related with

B. Smaller than

C. Equal to

D. Greater than

199. ________________ liquor is best handled in a long tube vertical evaporator ?
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A. Scaling

B. Viscous

C. Salting

D. Foamy
200. Normally, the ratio of the total riser area to the tower cross sectional area (for bubble cap towers of diameter more than 3 ft) is around_______________?
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A. 0.55-0.85

B. 0.1-0.2

C. 0.35-0.75

D. 0.4-0.6