chemical engineering process equipment and plant design MCQs – Page 3

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering process equipment and plant design Mcqs
101. Maximum size of the raschig rings used in a packed tower is about _______________ of the column diameter?
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A. 1/30th

B. 1/50th

C. 1/20th

D. 1/10th

102. Diameter of rivet hole (d, mm) and the plate thickness (t, mm) are related by Unwins formula as___________________?
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A. d = 1.6 ?t

B. d = 1.1 t

C. d = 1.5 t

D. d = 3 ?t

103. The approximate liquid depth in an agitation tank is equal to (where, d = tank diameter)_________________?
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A. d

B. 0.5 d

C. 0.75 d

D. 2 d

104. Filtration rate is affected by the________________?
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A. All A., B. and C.

B. Area of filtering surface & the viscosity of filtrate

C. Pressure drop across the cake & filter medium

D. Cake & filter medium resistance

105. For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between ______________________ times the tank diameter?
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A. 4 to 5

B. 2.5 to 3.5

C. 6 to 8

D. 1 to 1.5
106. The slope of the feed line in distillation operation is given by (where, q = fraction of the feed stream that is liquid ?
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A. #NAME?

B. -q/(1-q)

C. #NAME?

D. None of these

107. For pipe flows, head is proportional to ______________ at constant capacity (where D = pipe diameter) ?
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A. 1/D2

B. D2

C. 1/D5

D. 1/D

108. In most of the shell and tube heat exchangers, the tube pitch is generally ______________ the tube diameter?
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A. one-fourth of

B. 2.5 times

C. Less than

D. 1.25-1.50 times
109. Steam is preferred to be used as a heating medium in heat exchangers, because of its_________________?
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A. High latent heat

B. Non-corrosive condensate

C. High film co-efficient

D. Low cost

110. Liquid/petroleum fuel storage tanks are built underground (as in case of petrol pumps), when the storage capacity is less than ______________ kilolitres?
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A. 20

B. 45

C. 85

D. 30

111. Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter) ?
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A. 0.80 D

B. 0.66 D

C. 0.5 D

D. 0.2 D
112. The minimum tray spacing in distillation column of diameter less than 3 ft is normally _____________ inches?
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A. 24

B. 34

C. 6

D. 18

113. (Le/D) for fully open gate valves would be __________________?
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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.
114. A riveted joint does not fail by _____________________ of rivets?
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A. Shearing

B. Tearing

C. None of these

D. Tearing of the plate across a row

115. In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference ______________________?
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A. Is always more than arithmetic mean value and the geometric mean value

B. Is always less than arithmetic average 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

E. ther the flow of stream is co-current or counter-current

116. For a cylindrical internally pressurised vessel, which of the following closure types would withstand highest pressure, if each closure is of the same material and thickness ?
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A. Flat plate

B. Hemispherical

C. Conical

D. Ellipsoidal (2 : 1)
117. Correct use of factor of safety is very important in equipment design. It is defined as the ratio of the___________________?
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A. Ultimate stress to breaking stress

B. Working stress to ultimate stress

C. None of these

D. Ultimate stress to working stress
118. In a continuous distillation column, the optimum reflux ratio ranges from _______________ times the minimum reflux ratio?
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A. 2.2 to 2.6

B. 2.7 to 3

C. 1.6 to 2

D. 1.1 to 1.5
119. Vertical condenser is advantageous to the horizontal condenser from operation point of view, when________________?
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A. Hydrostatic head is required for refluxing the condensate

B. Only the function of condensation is to be carried out

C. Sub-cooling of condensate is desired

D. Both the functions of condensation & sub cooling are carried out in a single unit
120. In actual operation of a bubble cap distillation tower, the ______________ at the bottom of the tower is more than that at the top of the tower?
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A. Vapour molecular weight

B. Pressure and temperature

C. Molal flow rate of vapour

D. All A., B. and C.
121. Which of the following packing materials provides for maximum mass transfer ?
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A. All give the same value

B. Cross-partition rings

C. Raschig rings

D. Raschig rings

122. Bubble cap plate column is___________________?
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A. Used only for distillation, not for absorption

B. A continuous contactor

C. A finite stage contactor

D. A differential stage contactor

123. To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of_________________?
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A. (1.2)3/5

B. (1.2)3/2

C. (1.2)2/3

D. (1.2)5/3
124. n the agitators, the power required will be changed with the increase of diameter of agitator D. as ____________________?
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A. D5

B. D2

C. D

D. D9

125. The ratio of linear stress to linear strain is termed as the ____________________?
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A. Modulus of rigidity

B. None of these

C. Bulk modulus

D. Modulus of elasticity
126. Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, ? = yield strength and E = modulus of elasticity) ?
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A. E

B. ?

C. E/?

D. ?/E
127. Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger________________?
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A. Permits the use of less tubes in a given shell diameter

B. Facilitates comparatively easier external cleaning because of large clearance

C. Permits the use of more tubes in a given shell diameter

D. Both B. and C.

128. The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about _________________ mm of water column per metre height of packing?
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A. 100-150

B. 5-Jan

C. 20-40

D. 1000-1500

129. Width and depth of grooves in the tube sheet holes normally are _______________ inch respectively?
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A. 1/64 and 1/8

B. 1/2 and 8

C. 1/2 and 5

D. 1/8 and 1/64
130. Overall tray efficiency of a distillation column is the ratio of the number of ___________________?
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A. Overall gas transfer units to the number of ideal trays required

B. Ideal trays required to the number of real trays required

C. Real trays required to the number of ideal trays required

D. None of these

131. Thin spherical shells subjected to internal pressure, develop ______________ stresses?
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A. Radial

B. Circumferential

C. Both A. & B.

D. Neither A. nor B.

132. Speed of industrial paddle agitator ranges from _____________ rpm?
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A. 500 to 750

B. 1000 to 2000

C. 20 to 100

D. 1 to 5

133. Accidents in chemical plants are mostly due to___________________?
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A. Improper layout of the equipments

B. Failure of equipments

C. Inadequate equipment design

D. Faulty operating procedures
134. Welded joint efficiency in the design of chemical process equipment is taken as_________________?
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A. 0.75

B. 0.95

C. 0.85

D. 0.55

135. In case of design of a shell and tube heat exchanger___________________?
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A. mm tube diameter; and for > 15 mm tube diameter, tube sheet thickness is smaller than

B. All A., B. & C.

C. Minimum cleaning lane of 6.5 mm is provided, when tubes are on a square pitch

D. Minimum tube sheet thickness (in which tubes are fixed) is equal to the O.D. of the tube upto

E. 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

F. e diameter

136. 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__________________?
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A. Corner torus section and central dished section

B. Central dished section and corner torus section

C. Central dished section and straight flange section

D. Straight flange section and corner torus section

137. Length to diameter ratio of most rotary driers is in the range of____________________?
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A. 10 to 20

B. 20 to 30

C. 4 to 10

D. 1 to 2

138. 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?
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A. 1/10-1/15th

B. 1/5-1/10th

C. 1/2 to 1/4th

D. 1/20-1/30th

139. Column support for the roof of cylindrical storage tank must be provided for___________________?
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A. All tanks irrespective of their heights and diameters

B. Large diameter tanks

C. Small diameter tanks

D. Small diameter tall tanks

140. Poissons ratio of a material is the ratio of unit lateral strain to the unit axial elongation within its elastic limit. The value of Poissons ratio for structural and pressure vessel steel may be taken as ____________________?
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A. 0.95

B. 0.3

C. 0.75

D. 0.01

141. Heat transfer co-efficient, hG(Kcal/hr.m2 .C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to ____________________?
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A. hG = 1.004G0.37

B. 1.004G0.8

C. hG = 0.0176G0.37

D. 0.0176G1.37

142. Generally, elliptical dished heads____________________?
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B. ll of the same thickness and diameter

C. Resist half the pressure rating compared to hemi spherical head provided on the cylindrical

D. Are approximately as strong as seamless cylindrical shell having the corresponding I.D and

E. Are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for

F. ssure vessels operating above a pressure of 1.5 MN/m2

143. For a cylindrical vessel of moderate height, the weld joint efficiency for joints parallel to the cylindrical axis is given as 1.0; while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylindrical vessel, what value of weld joint efficiency should be used ?
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A. 0.8

B. (0.8)0.5

C. 1

D. 0.9

144. Larger depth of liquid on the trays of a distillation column_________________?
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A. Leads to high tray efficiency

B. Results in higher pressure drop per tray

C. Both A. & B.

D. Neither A. or B.

145. Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the_______________?
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A. Flow rates of each fluid

B. Concentration of each fluid

C. All A, B. & C.

D. Type and size of packing

146. The equivalent diameter for fluid flow through a channel of constant non-circular cross section of area A is given by (where, P = perimeter of the channel in contact with the fluid) ?
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A. ?A

B. 4 P/A

C. A/P

D. 4 A/P
147. Maximum allowable vapour velocity in a bubble cap tower is determined by the ____________________?
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A. None of these

B. Vapour density

C. Entrainment considerations

D. Diameter of the column

148. Hole diameter of the sieve trays in the distillation column ranges from ______________ mm?
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A. 3 to 12.5

B. 1 to3

C. 4 to 8

D. 12.5 to 18.5

149. It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than _________________?
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A. 0.95

B. 0.80

C. 0.99

D. 0.55

150. In packed absorption tower, onset of flooding usually occurs at a pressure drop of about ______________ mm of water column per metre height of packing?
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A. 50-75

B. 750-1000

C. 25-50

D. 200-250