chemical engineering mechanical operations MCQs – Page 3

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering mechanical operations Mcqs
41. Filtration capacity of a rotary drum vacuum filter depends upon the_______________?
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A. Cake thickness

B. Characteristics of the feed slurry

C. Both A. & B.

D. Neither A. nor B.

42. In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the__________________?
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A. Washing time only

B. Square of the viscosity

C. Filtration time only

D. Square root of the velocity
43. The power number for a stirred tank becomes constant at high Reynolds number. In this limit, the variation of power input with impeller rotational speed (N) is proportional to___________________?
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A. N2

B. N3

C. N1

D. N

44. Pick out the wrong statement ?
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A. versal jaw crushers

B. Operating principles of Dodge and Blake jaw crushers are combined in the working of

C. Cutting machines mainly employ attrition for size reduction of solids

D. er one

E. uction equipments employ

F. There are only four methods namely compression, impact, attrition and cutting, which the size

45. ______________ mill is not a revolving mill ?
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A. Pebble

B. Tube

C. Compartment

D. Cage
46. Which is the most suitable conveyor for transportation of sticky material ?
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A. Pneumatic conveyor

B. Screw conveyor

C. Apron conveyor

D. Belt conveyor

47. Crushing efficiency is the ratio of the ______________________ ?
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A. Energy absorbed by the solid to the surface energy created by crushing

B. Surface energy created by crushing to the energy absorbed by the solid

C. Energy fed to the machine to the surface energy created by crushing

D. Energy absorbed by the solid to that fed to the machine

48. Fluid energy mill comes in the category of________________?
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A. Cutter

B. Grinder

C. Ultrafine grinder

D. Crusher

49. The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an______________?
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A. Cyclone separator

B. Electrostatic precipitator

C. Wet scrubber

D. Bag filter

50. Raw materials are charged in the iron blast furnace using____________________?
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A. Skip hoist

B. Bucket elevator

C. None of these

D. Screw conveyor

51. Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity ?
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A. Cube

B. Cylinder (L/D = 1)

C. Sphere

D. Raschig rings

52. Maximum size reduction in a fluid energy mill is achieved by___________________?
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A. Interparticle attrition

B. Impact

C. Cutting

D. Compression

53. For raschig rings, the sphericity is_____________________?
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A. ?3

B. 0.5

C. < 1

D. 1

54. Trommels are revolving screens which normally operate in the range of _______________ rpm?
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A. 1 2

B. 15 20

C. 40 50

D. 60 75

55. For removal of very small amounts of precipitate from large volume of water, the most suitable filter is the ______________ filter?
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A. Shell & leaf

B. Rotary vacuum

C. Plate & frame

D. Sand
56. Tube mill compared to ball mill_______________________?
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A. Is long in comparison with its diameter

B. Produces finer products

C. All A., B. & C.

D. Uses smaller balls

57. Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is_______________?
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A. Added to the feed slurry

B. Pre-coated on the filter medium prior to filtration

C. Separated from the cake by dissolving solids or by burning it off

D. All A, B. & C.
58. Filtration rate through a filter cake is proportional to (where, S = filtering surface R = specific cake resistance ? = viscosity of the filtrate) ?
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A. 1/?

B. S

C. All A., B. & C.

D. 1/R

59. To get a fine talc powder from its granules, the equipment used is____________________?
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A. Roller crusher

B. Ball mill

C. Gyratory crusher

D. Jaw crusher

60. Kicks law assumes that the energy required for size reduction is proportional to the logarithm of the ratio between the initial and the final diameters. The unit of Kicks constant is_________________?
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A. kg/sec

B. kWh/sec. kg

C. kW. sec/kg

D. kWh/kg