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1) A high vapour velocity is required for high plate efficiency in a sieve plate column. The satisfactory value of operating vapor velocity for design purpose in sieve plate column is about _______________ percent of the flooding velocity? a. 45 b. 60 c. 80 d. 95
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2) Number of evaporators which can be used in service in a multiple effect evaporation system is limited by the__________________? a. Practical limit reached, due to low heat transfer rate because of inadequate temperature difference b. Economic limit reached, when the plant cost exceeds the saving of steam c. Both A. & B. d. Neither A. nor B.
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3) The retention time of material in a rotary dryer depends upon its ______________________? a. rpm b. Slope & length c. Flights arrangement d. All A., B. and C.
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4) 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? a. About 9 b. Considerably more than 9 c. Considerably less than 9 d. About 3
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5) Generally, elliptical dished heads____________________? a. Are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for pressure vessels operating above a pressure of 1.5 MN/m2 b. Resist half the pressure rating compared to hemi spherical head provided on the cylindrical shell of the same thickness and diameter c. Are approximately as strong as seamless cylindrical shell having the corresponding I.D and O.D d. All A., B. and C.
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6) Hold up of material in a operating rotary drier is in the range of___________________? a. 0.05 to 0.15 b. 0.25 to 0.50 c. 0.5 to 0.8 d. 0.8 to 0.9
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7) ______________ of water makes it a widely used coolant in heat exchangers? a. Low corrosiveness b. Low dirt factor c. High specific heat d. Low viscosity
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8) A head comprises of straight flange section, corner torus, section and central dished section. Crown radius and knuckle radius in a head is related respectively to the__________________? a. Central dished section and corner torus section b. Corner torus section and central dished section c. Central dished section and straight flange section d. Straight flange section and corner torus section
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9) In a distillation column, the minimum residence time for liquid in the downspout is about ______________ seconds? a. 1 b. 8 c. 80 d. 180
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10) Pressure drop due to pipe fittings can be estimated by the equation, ΔP/ρ = 4f, (Le/D) (V2/2gc) where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of (Le/D) (dimensionless) for 45° elbow and 180° close return bends would be respectively around______________________? a. 5 and 10 b. 45 and 75 c. 180 and 300 d. 300 and 500
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11) In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube ? a. Long tube vertical evaporator b. Short tube vertical evaporator c. Horizontal tube evaporator d. None of these
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12) ________________ liquor is best handled in a long tube vertical evaporator ? a. Foamy b. Scaling c. Viscous d. Salting
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13) The equivalent diameter for pressure drop is _______________ that for heat transfer? a. Smaller than b. Greater than c. Equal to d. Not related with
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14) With increase in gas flow rate to fabric surface area ratio (Nm3/hr/m2 fabric surface area), the size & the cost of a bag filter___________________? a. Increases b. Decreases c. Remain unaffected d. None of these
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15) 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.
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16) Cylindrical pressure vessels in horizontal condition is generally supported on a ________________ support? a. Lug b. Skirt c. Saddle d. Guy wire
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17) Pick out the wrong statement pertaining to the comparative evaluation of performance of the packed tower and the plate tower ? a. Plate tower is preferred, if interstage cooling is required to remove heats of reaction or solution b. Plate tower is preferred over packed tower, if the operation involves liquids containing dispersed solids c. The total weight of a dry plate tower is usually much more than that of a dry packed tower designed for the same duty d. In operations involving large temperature changes. (e.g. distillation), plate towers are preferred over packed towers as the packing may be crushed du
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18) Flanges are connected to pipes by _______________________? a. Screwing b. Welding c. Brazing d. All A., B. and C.
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19) 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
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20) The maximum liquid gradient over a tray must not exceed__________________? a. 0.5″ -1.25″ b. 2″-3.5″ c. 5″ d. Half the tray spacing
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