chemical engineering process equipment and plant design Mcqs
351. A minimum clearance of about _______________ mm is maintained between the distillation column wall and the bubble cap?
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A. 19

B. 95

C. 67

D. 38
352. Pressure differential maintained across a continuous rotary vacuum filter is in the range of _______________ mm Hg column?
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A. 600 to 700

B. 250 to 500

C. 50 to 100

D. 100 to 150

353. Pick out the wrong statement?
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A. The value of crushing load is more than that of buckling load for long columns

B. The tensile strength of a brittle material is less than its compressive strength

C. The compressive strength of a ductile material is less than its tensile strength

D. In a thick cylindrical shell, the hoop stress is maximum at the inner radius

354. Typical static submergence for bubble cap plate column operating at atmospheric pressure may be around _________________?
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A. 50% of the plate spacing

B. 2.5?

C. 0.5?

D. 5?

355. (Le/D) for a Tee (used as elbow, entering branch) would be ____________________?
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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.
356. Pick out the wrong statement pertaining to the design of a basket type evaporator ?
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A. It is used for high viscosity liquor having large rate of scaling

B. Downtake is formed by the annular space between the bundle and the shell

C. There is no central downtake

D. The tube bundle is suspended on bracket

357. Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column ?
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A. Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for sieve and valve trays than the bubble cap

B. Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates

C. Maintenance cost for valve and sieve trays are comparatively more than bubble cap tray due to their relatively complicated construction features

D. Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provide the maximum flexible operating range

358. In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to____________________?
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A. 2

B. 20.8

C. ?

D. 1
359. Slope of counter-current flow rotary drier is in the range of ____________ meter/metre?
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A. 0 to 0.8

B. 0 to 1.5

C. 0 to 0.08

D. 0 to 2.2

360. Optimum economic pipe diameter for fluid flow is determined by the____________________?
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A. None of these

B. Density of the fluid

C. Total cost considerations (pumping cost plus fixed cost of the pipe)

D. Viscosity of the fluid

361. In a shell and tube heat exchanger, triangular pitch arrangement as compared to square pitch arrangement ?
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A. Can accomodate less number of tubes for a given shell diameter

B. Creates relatively lower turbulence on the shell side resulting in lower shell side heat transfer

C. efficient

D. e fluid

E. Facilitates easier shell side cleaning; hence is more suitable for handling high dirt factor shell

F. Results in higher shell side pressure drop
362. Weep holes provided in the plates of a distillation column ____________________?
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A. essive amount of fluid during operation

B. lows approximately the same path as the overflow fluid

C. Are normally located near the overflow weir so that any delivery of liquid during operation

D. All A., B. and C.

E. Must be large enough (usually 1/4? to 5/8? dia) to prevent plugging but should not deliver

F. Facilitate draining out liquid from a tray when the unit is not in operation

363. Which of the following types of reactors is the safest from operation point of view ?
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A. A liquid phase reactor

B. A vapor phase reactor

C. A liquid phase catalytic reactor

D. Pot type reactor

364. The ratio, (propeller agitator dia/tank dia) is normally taken as____________________?
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A. 0.5-0.65

B. 0.15-030

C. 0.60-0.90

D. 0.75-0.85

365. To avoid the tearing off the plate of an edge, the margin (i.e., the minimum distance from the centre of the rivet hole to the nearest edge of the plate) should be equal to ____________________?
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A. 2.5 d

B. 1.5 d

C. 0.5 d

D. d

366. Pick out the correct statement ?
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A. Packed towers are generally preferred over plate towers, if the liquids have a foaming tendency

B. The pressure drop through the packed towers is generally more than the pressure drop through plate towers designed for same duty

C. None of these

D. When highly corrosive fluids are to be handled, the plate towers prove to be cheaper and easier to construct than packed tower

367. A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending upto double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design____________________?
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A. Irrespective of the shape of the vessel

B. Only if the opening is on a horizontal cylindrical vessel

C. Only if the opening is on spherical vessel

D. Only if the opening is on a vertical cylindrical vessel

368. Pick out the wrong statement about the design of a sieve plate column ?
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A. An increased weir height improves the tray efficiency at the cost of high plate pressure drop; optimum wear height being 40-90 mm for column pressure above atmospheric and 6-12 mm for vacuum columns

B. For segmental downcomers, the chord length is 60-80% of the column diameter. An initial value of downcomer area of 12% is taken in the design

C. Width of the calming section provided at the inlet and outlet sides of the plate is 75 mm for column diameter below 1.5 metres and 100 mm for larger diameter columns

D. Minimum recommended downcomer residence time for the disengagement of entrained vapour is the same for both foaming and non-foaming liquids, which is about 20 seconds