chemical engineering process equipment and plant design Mcqs
51. What is the slope of the feed line, if the feed to a distillation column is a saturated liquid ?
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A. 0

B. ?

C. < 1

D. > 1

52. Value of Peclet number = ?, is the representative of___________________?
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A. Complete back mixing

B. Plug flow

C. Eddy diffusivity = 0

D. Laminar flow

53. Practical dividing line between a ductile and brittle materials is suggested, when the ultimate elongation is about 5%. Generally, larger the knuckle radius, stronger is the corner torus section of a head. The knuckle radius provided should be less than ______________ of the head?
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A. Either A. or B., whichever is larger

B. 6% of I.D.

C. Either A. or B., whichever is smaller

D. 3 times the thickness

54. For turbulent flow (NRe > 2100) of low viscosity fluid (? > 20cp) in steel pipes, the optimum inside pipe diameter is given by(where, Q = fluid flow rate, ft3/sec, ? = fluid density, lb/ft3 ? = fluid viscosity, centipoise Di = optimum inside pipe diameter, inches) ?
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A. Di, opt = 4.7 Q0.36. ?3.2?0.13

B. Di, opt = 3.9 Q0.45. ?0.95

C. Di, opt = 3.9 Q0.45 ?0.13

D. Di, opt = 3 Q0.36. ?0.88

55. In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around __________________?
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A. 0.5

B. 1.5

C. 2.5

D. 3.5

56. A/an _______________ is used for changing the direction of a pipeline?
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A. Union

B. Flange

C. Disc compensator

D. Elbow
57. In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the_______________?
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A. Liquid gradient on the tray

B. Small downcomer liquid seal

C. Lower skirt clearance

D. Lower static submergence

58. Factor of safety (i.e., overdesign factor) in heat transfer equipments is about _____________ percent more than the actual/theoretical design factor?
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A. 15-20

B. 30-35

C. 35-40

D. 10-May

59. Log mean temperature difference in case of multi-pass shell and tube heat exchanger is always_________________?
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A. Less than arithmetic mean value

B. More than arithmetic mean value

C. More than geometric mean value

D. Both B. & C.

60. Stage efficiency for packed tower varies with the____________________?
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A. All A., B. and C.

B. Type & size of packing

C. Operating pressure and column diameter

D. Fluid rates and fluid properties

61. (Le/D) for fully open globe value may be around__________________?
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A. 10

B. 25

C. 300

D. 75

62. Reflux ratio variation in a distillation column is between___________________?
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A. None of these

B. Zero and infinity

C. Minimum and infinity

D. Zero and one

63. A stuffing box is used for____________________?
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A. Absorbing the contraction/expansion of pipeline due to temperature changes

B. Facilitating smooth opening and closing of a valve

C. Reducing the resistance of fluid flow

D. Prevention of fluid leakage around moving parts
64. Pick out the wrong statement about routing of fluids in a shell and tube heat exchanger ?
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A. The viscous fluid should be routed through the shell side

B. The corrosive and fouling fluid should be preferably routed through the tubes

C. Higher pressure fluid stream should be routed through the shell side

D. Lower flow rate fluid should be routed through the shell side

65. _____________________ tray arrangement is recommended for distillation column having diameter upto 4 ft ?
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A. Cross flow

B. Split flow

C. Radial flow

D. Cascade

66. Joint efficiency (J) for a seamless pipe is_______________?
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A. < 0.5

B. 1

C. 0.85

D. 1.5

67. Multiple blade paddle agitator is used for mixing high viscosity liquids/paste in which the paddle diameter is commonly 0.8 times the tank diameter. However, the width of the blade is in the range of ______________ times the paddle diameter?
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A. 0.5 to 0.6

B. 0.65 to 0.80

C. 0.3 to 0.5

D. 0.1 to 0.25
68. ____________ head is the most economical for cylindrical vessels designed for operating at high pressure (> 15 atm.)?
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A. Hemispherical

B. Conical

C. Ellipsoidal

D. Dished

69. The clearance between two tubes in a shell and tube heat exchanger is known as ligament, whose minimum value is _____________ the outside diameter of the tube, but in no case it should be less than 4.5 mm?
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A. Three fourth

B. Half

C. One fourth

D. Equal to

70. The stress developed in a material without any permanent set is called the____________________?
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A. Breaking stress

B. Elastic limit

C. Ultimate stress

D. Yield stress

71. Pressure drop per tray in the atmospheric distillation column is about ________________ psi?
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A. 0.01 0.5

B. 0.5 1.0

C. 1 3

D. 0.07 0.12
72. Which of the following lengths of heat exchanger tubes are normally not used in practice ?
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A. 6 metres

B. 10 metres

C. 0.5 metre

D. 2.5 metres

73. The force due to wind load acting on a tall vessel depends upon its___________________?
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A. Shape

B. All A, B. & C.

C. Height

D. Outside diameter

74. The retention time of material in a rotary dryer depends upon its ______________________?
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A. Slope & length

B. Flights arrangement

C. rpm

D. All A., B. and C.
75. Pressure drop (?p) and the superficial gas mass velocity (G) in case of packed absorption tower operating in the preloading range are related as_________________?
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A. ?p = G0.5

B. ?p = G

C. ?p = 1/G0.6

D. ?p = G2
76. Lug support is meant for supporting _______________ vessels?
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A. Large horizontal cylindrical

B. Small

C. Thick walled tall

D. Tall but empty

77. In shell and tube heat exchangers, straight tie rods are used to_________________?
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A. Hold baffle in space

B. None of these

C. Account for thermal strain

D. Fix the tubes in position

78. Ponchon Savarit method is based on the use of enthalpy concentration diagram, which contains the bubble point curve (saturated liquid curve), dew point curve (saturated vapour curve) and equilibrium tie lines. As compared to McCabe-Thieles method, this method_________________?
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A. accounts for the enthalpy changes in the process

B. s method

C. is more accurate in finding the number of equilibrium stages

D. Facilitates direct calculation of heat load on reboiler & condenser from, the diagram used in

E. All A, B. & C.
79. Hoop (circumferential) stress induced in a thin walled Horton Sphere used for the storage of liquid ammonia under pressure is____________________?
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A. pD/3T

B. pD/4T

C. pD/2T

D. pD/6T

80. Pick out the wrong statement pertaining to the design of a long tube vertical evaporator ?
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A. Steam is fed to the shell, whereas the liquor is filled inside the tube

B. Tube dia is 3-6 cms, while tube length in 3-6 metres

C. Liquor level is maintained at 1/3rd to 1/2 of the height of the tube

D. None of these
81. In a distillation column, the minimum residence time for liquid in the downspout is about ______________ seconds?
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A. 8

B. 180

C. 80

D. 1

82. With increase in temperature drop (in a shell and tube heat exchanger), the LMTD correction factor, FT_________________?
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A. Decreases very rapidly

B. Remains constant

C. Increases linearly

D. Increases very rapidly

83. In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about _______________ cms?
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A. 35

B. 10

C. 20

D. 30

84. In a multipass shell and tube heat exchanger, the baffles on shell side is primarily provided for______________?
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A. Fixing the tubes

B. Creating turbulence

C. Reducing scale deposition

D. Increasing pressure drop

85. Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is _____________ the longitudinal stress?
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A. Equal to

B. Eight times

C. Half

D. Twice
86. In the design of a paddle agitator, the ratio (paddle dia/tank dia) is normally taken as___________________?
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A. 0.1

B. 0.25

C. 0.8

D. 0.5

87. A cylindrical storage tank can have a self supported conical roof ?
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A. Irrespective of its diameter

B. If the thickness of the roof is more than that of the cylindrical shell

C. If its diameter is less than 15-20metres

D. If its diameter is more than 50 meters

88. Flanges are connected to pipes by _______________________?
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A. Welding

B. All A., B. and C.

C. Brazing

D. Screwing

89. The ratio of down take area to cross-sectional area of the tube, for calandria type evaporator ranges from_________________?
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A. 1 to 1.5

B. 0.5 to 1

C. 1.5 to 2

D. 2 to 2.5

90. The most common standard size of bubble caps used in industrial operation is___________________?
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A. 4? dia cap with 8? dia riser

B. 6? dia cap with 4? dia riser

C. 8? dia cap with 1? dia riser

D. 1? dia cap with 0.5? dia riser

91. Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate ?
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A. 8

B. 2

C. 4

92. _______________ shaped roof is most commonly used for cylindrical tanks ?
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A. Dome

B. Cone

C. Umbrella

D. Flat

93. Friction factor for turbulent flow in a new pipe is given by____________________?
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B. f = 0.04/(NRe)0.16

C. f = 0.22 NRe

D. f = 25/NRe

E. f = 16/NRe

94. Compensation against openings in process vessels for giving inlet and outlet connections, for providing sight glasses and manholes etc. is provided for strength and rigidity. The most efficient type of compensation is of _______________ type?
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A. Ring plate

B. Flared out

C. Fluid in

D. Nozzle or rim
95. LMTD correction factor is used in heat exchanger design for____________________?
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A. Multipass shell and tube heat exchanger

B. Fouling fluids

C. Double pipe heat exchanger

D. Counter flow of hot and cold fluids
96. Brass valves are usually made for pipe sizes ______________ inches?
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A. > 2.5

B. > 3.5

C. ? 2

D. ? 1

97. For a given design of bubble cap, the number of bubble caps to be used per tray is set by the _________________?
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A. Diameter of the column

B. Allowable gas velocity through the slots

C. Plate spacing

D. All A., B. and C.

98. In a distillation column, minimum clearance to be maintained between the overflow weir and the last row of the bubble caps is ______________ cms?
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A. 2.5

B. 20

C. 15

D. 7.5
99. For turbine agitator, the impeller diameter is about_________________?
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A. 0.95 d

B. 0.1 to 0.2 d

C. 0.65 to 0.85 d

D. 0.3 to 0.5 d
100. In a cylindrical vessel subjected to internal pressure, the longitudinal stress ?L and the circumferential stress, ?n are related by___________________?
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A. ?h = 2 ?L

B. ?h = ?L/2

C. No relation exists

D. ?h = ?L