MCQOPTIONS
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MCQOPTIONS
This section includes 324 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Maximum acceptable total liquid gradient over a tray is about _______________ mm? |
| A. | 5.5 |
| B. | 12.5 |
| C. | 30.5 |
| D. | 45.5 |
| Answer» C. 30.5 | |
| 152. |
Lug support is meant for supporting _______________ vessels? |
| A. | Large horizontal cylindrical |
| B. | Tall but empty |
| C. | Small |
| D. | Thick walled tall |
| Answer» D. Thick walled tall | |
| 153. |
Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about _______________ mm Hg (referred to a 760 mm mercury barometer)? |
| A. | 250 |
| B. | 450 |
| C. | 650 |
| D. | 750 |
| Answer» D. 750 | |
| 154. |
Longitudinal stress induced in a thin walled cylindrical storage vessel is __________________? |
| A. | pD/2t |
| B. | pD/4t |
| C. | pD/3t |
| D. | pD/6t |
| Answer» C. pD/3t | |
| 155. |
Log mean temperature difference in case of multi-pass shell and tube heat exchanger is always_________________? |
| A. | Less than arithmetic mean value |
| B. | More than arithmetic mean value |
| C. | More than geometric mean value |
| D. | Both B. & C. |
| Answer» B. More than arithmetic mean value | |
| 156. |
LMTD correction factor is used in heat exchanger design for____________________? |
| A. | Double pipe heat exchanger |
| B. | Multipass shell and tube heat exchanger |
| C. | Fouling fluids |
| D. | Counter flow of hot and cold fluids |
| Answer» E. | |
| 157. |
________________ liquor is best handled in a long tube vertical evaporator ? |
| A. | Foamy |
| B. | Scaling |
| C. | Viscous |
| D. | Salting |
| Answer» B. Scaling | |
| 158. |
Liquid/petroleum fuel storage tanks are built underground (as in case of petrol pumps), when the storage capacity is less than ______________ kilolitres? |
| A. | 20 |
| B. | 30 |
| C. | 45 |
| D. | 85 |
| Answer» D. 85 | |
| 159. |
Liquid redistribution should be done in a packed tower packed with raschig rings every 6 metres or ______________ times the column diameter, whichever is lower? |
| A. | 2.5-3.0 |
| B. | 5-7.5 |
| C. | 10-12.5 |
| D. | 15-20 |
| Answer» B. 5-7.5 | |
| 160. |
Liquid gradient over the tray results due to the___________________? |
| A. | Resistance offered to flow of liquids by caps & risers and the flow of gas |
| B. | Low gas velocity |
| C. | Large plate spacing |
| D. | Large reflux ratio |
| Answer» B. Low gas velocity | |
| 161. |
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 dis |
| C. | Using split flow, radial flow or cascade flow for column diameter large than 4 ft |
| D. | All A., B. and C. |
| Answer» E. | |
| 162. |
Length to diameter ratio of most rotary driers is in the range of____________________? |
| A. | 1 to 2 |
| B. | 4 to 10 |
| C. | 10 to 20 |
| D. | 20 to 30 |
| Answer» C. 10 to 20 | |
| 163. |
(Le/D) for fully open gate valves would be __________________? |
| A. | Much more than that for fully open globe valves |
| B. | Much less (say 2% than that for fully open globe valves) |
| C. | Around 7 |
| D. | Both B. and C. |
| Answer» E. | |
| 164. |
(Le/D) for fully open globe value may be around__________________? |
| A. | 10 |
| B. | 25 |
| C. | 75 |
| D. | 300 |
| Answer» E. | |
| 165. |
(Le/D) for couplings and unions would be_______________? |
| A. | 60 |
| B. | 200 |
| C. | 350 |
| D. | Negligible |
| Answer» E. | |
| 166. |
(Le/D) for a Tee (used as elbow, entering run) would be around _______________________? |
| A. | 5 |
| B. | 60 |
| C. | 160 |
| D. | 200 |
| Answer» C. 160 | |
| 167. |
(Le/D) for a Tee (used as elbow, entering branch) would be ____________________? |
| A. | Less than that for Tee (used as elbow, entering run) |
| B. | More than that for Tee (used as elbow, entering run) |
| C. | Around 90 |
| D. | Both B. and C. |
| Answer» E. | |
| 168. |
Le/D) for 90° elbow (medium radius) and 90°square elbow would be respectively around___________________? |
| A. | 25 and 60 |
| B. | 3 and 5 |
| C. | 100 and 250 |
| D. | 250 and 600 |
| Answer» B. 3 and 5 | |
| 169. |
Larger depth of liquid on the trays of a distillation column_________________? |
| A. | Leads to high tray efficiency |
| B. | Results in higher pressure drop per tray |
| C. | Both A. & B. |
| D. | Neither A. or B. |
| Answer» D. Neither A. or B. | |
| 170. |
Large process vessels operating under extreme temperature and pressure conditions are normally clad/ lined with materials like stainless steel, aluminium, nickel & its alloys, copper & its alloys and titanium. The cladding thickness is generally about ______________ percent of the total thickness? |
| A. | 1 to 5 |
| B. | 10 to 20 |
| C. | 30 to 40 |
| D. | 40 to 50 |
| Answer» C. 30 to 40 | |
| 171. |
Lap joints are preferred for plates having thickness _______________ mm? |
| A. | < 12.5 |
| B. | > 3 |
| C. | > 5 |
| D. | 5-10 |
| Answer» C. > 5 | |
| 172. |
Joint efficiency (J) for a seamless pipe is_______________? |
| A. | 1 |
| B. | 0.85 |
| C. | 1.5 |
| D. | < 0.5 |
| Answer» B. 0.85 | |
| 173. |
It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than _________________? |
| A. | 0.99 |
| B. | 0.95 |
| C. | 0.80 |
| D. | 0.55 |
| Answer» D. 0.55 | |
| 174. |
____________ is the determining factor for the number of bubble caps to be used per tray? |
| A. | Permissible slot velocity |
| B. | Tray diameter |
| C. | Liquid load |
| D. | Vapor load |
| Answer» B. Tray diameter | |
| 175. |
In the downcomer of a distillation column, the minimum recommended residence time is about _______________ seconds? |
| A. | 2.5 |
| B. | 5 |
| C. | 12.5 |
| D. | 17.5 |
| Answer» C. 12.5 | |
| 176. |
In the design of a shell and tube heat exchanger, the corrosion allowance ____________________? |
| A. | Need not be provided for non-pressure parts like tie rods, spacers, baffles, supports etc. |
| B. | For carbon steel and cast iron pressure parts is 1.5 mm (except for tubes) and for severe conditions it is 3 mm |
| C. | For internal cover and tube sheet is provided on both the sides |
| D. | All A., B. & C. |
| Answer» E. | |
| 177. |
In the design of a paddle agitator, the ratio (paddle dia/tank dia) is normally taken as___________________? |
| A. | 0.1 |
| B. | 0.8 |
| C. | 0.25 |
| D. | 0.5 |
| Answer» C. 0.25 | |
| 178. |
In the design of a bag filter, the gas temperature is an important consideration, as it affects the___________________? |
| A. | Gas density |
| B. | Gas viscosity |
| C. | Fibre selection |
| D. | All A., B. & C. |
| Answer» E. | |
| 179. |
In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference ______________________? |
| A. | Is always less than arithmetic average value |
| B. | Is always more than arithmetic mean value and the geometric mean value |
| C. | Is always less than arithmetic mean value, but more than geometric mean value |
| D. | May be either more or less than geometric mean and arithmetic mean value depending upon whether the flow of stream is co-current or counter-current |
| Answer» B. Is always more than arithmetic mean value and the geometric mean value | |
| 180. |
In the allocated cap area, bubble caps are generally arranged on equilateral triangular pitch. Number of caps fixed on a plate is with a __________________? |
| A. | Clearance of 25-75 mm |
| B. | Cap pitch of 1.3-2 times the cap diameter |
| C. | Either A. or B. |
| D. | Neither A. nor B. |
| Answer» D. Neither A. nor B. | |
| 181. |
In sieve plate column, holes are drilled or punched in sizes ranging from 2.5 to 12 mm (5 mm being widely used). The hole pitch is normally ______________ times the hole diameter to give the required hole area? |
| A. | 0.5 to 1.5 |
| B. | 2.5 to 4.0 |
| C. | 5 to 10 |
| D. | 10 to 15 |
| Answer» C. 5 to 10 | |
| 182. |
In shell and tube heat exchangers, straight tie rods are used to_________________? |
| A. | Hold baffle in space |
| B. | Fix the tubes in position |
| C. | Account for thermal strain |
| D. | None of these |
| Answer» B. Fix the tubes in position | |
| 183. |
In packed towers provided with saddle packing, liquid redistributors are positioned at every _______________ times column diameter or 6 metres whichever is less? |
| A. | 2-3 |
| B. | 5-8 |
| C. | 10-15 |
| D. | 20-25 |
| Answer» C. 10-15 | |
| 184. |
In packed towers provided with pall rings liquid redistributors are positioned at heights of every 6 metres or 5-10 times the column diameter, whichever is less. Maximum size of the pall rings should not exceed _______________________ of the column diameter? |
| A. | 1/10-1/15th |
| B. | 1/5-1/10th |
| C. | 1/20-1/30th |
| D. | 1/2 to 1/4th |
| Answer» B. 1/5-1/10th | |
| 185. |
In packed absorption tower, onset of flooding usually occurs at a pressure drop of about ______________ mm of water column per metre height of packing? |
| A. | 25-50 |
| B. | 50-75 |
| C. | 200-250 |
| D. | 750-1000 |
| Answer» C. 200-250 | |
| 186. |
In most of the shell and tube heat exchangers, the tube pitch is generally ______________ the tube diameter? |
| A. | Less than |
| B. | 1.25-1.50 times |
| C. | 2.5 times |
| D. | one-fourth of |
| Answer» C. 2.5 times | |
| 187. |
In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around __________________? |
| A. | 0.5 |
| B. | 1.5 |
| C. | 2.5 |
| D. | 3.5 |
| Answer» C. 2.5 | |
| 188. |
In distillation columns, bubble caps are held in place over trays by ________________? |
| A. | Rivets |
| B. | A hold down bar |
| C. | Bolts |
| D. | Both B. and C. |
| Answer» E. | |
| 189. |
In condenser, the cooling water is passed in the tube side in a pass arrangement, because________________? |
| A. | It reduces heat transfer area |
| B. | More thinner tubes can be used |
| C. | Pressure drop is reduced |
| D. | It makes condenser compact |
| Answer» B. More thinner tubes can be used | |
| 190. |
In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area) ? |
| A. | Aa = Sa |
| B. | 1.2 Aa = 1.2 Sa |
| C. | Sa = 1.5 Aa |
| D. | Aa = 1.5 Sa |
| Answer» B. 1.2 Aa = 1.2 Sa | |
| 191. |
In case of saddle packing (e.g., berl and intralox saddles), the maximum size of the packing should not exceed ______________ of the column diameter? |
| A. | 1/5th |
| B. | 1/15th |
| C. | 1/30th |
| D. | 1/50th |
| Answer» C. 1/30th | |
| 192. |
In case of plain carbon steel, butt welded joints are used for shell plate thickness ≤ _____________ cms? |
| A. | 1.2 |
| B. | 0.5 |
| C. | 3.8 |
| D. | 6.8 |
| Answer» D. 6.8 | |
| 193. |
In case of design of a shell and tube heat exchanger___________________? |
| A. | Minimum cleaning lane of 6.5 mm is provided, when tubes are on a square pitch |
| B. | Minimum tube sheet thickness (in which tubes are fixed) is equal to the O.D. of the tube upto 15 mm tube diameter; and for > 15 mm tube diameter, tube |
| C. | O.D. of the tube is 6 to 40 mm while the tube lengths used are 0.5, 2.5, 3.0, 4.0, 5.0, 6 metres |
| D. | All A., B. & C. |
| Answer» E. | |
| 194. |
In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about _______________ cms? |
| A. | 10 |
| B. | 20 |
| C. | 30 |
| D. | 35 |
| Answer» B. 20 | |
| 195. |
In case of a ‘thin’ pressure vessel, the ratio of its diameter to wall thickness is_________________? |
| A. | < 10 |
| B. | > 10 |
| C. | > 20 |
| D. | 30 |
| Answer» C. > 20 | |
| 196. |
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? |
| A. | 3-5 |
| B. | 5-11 |
| C. | 8-15 |
| D. | 12-18 |
| Answer» C. 8-15 | |
| 197. |
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_____________? |
| A. | 1000 |
| B. | 3000 |
| C. | 5000 |
| D. | 10000 |
| Answer» E. | |
| 198. |
In case of a continuous distillation column, increase in reflux ratio may result in the______________? |
| A. | Lower fixed charges for the column |
| B. | Greater cost for the reboiler heat supply |
| C. | Greater cost for the condenser coolant |
| D. | All A., B. and C. |
| Answer» E. | |
| 199. |
In case of 1.5″ heat exchanger tubes, the inside flow area _____________ with decrease in BWG? |
| A. | Increases |
| B. | Decreases |
| C. | Remains same |
| D. | None of these |
| Answer» C. Remains same | |
| 200. |
In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the_______________? |
| A. | Liquid gradient on the tray |
| B. | Lower skirt clearance |
| C. | Lower static submergence |
| D. | Small downcomer liquid seal |
| Answer» B. Lower skirt clearance | |