chemical engineering mechanical operations MCQs – Page 10

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 Review each marked answer and report any item that may be outdated or unclear.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
181. _____________ is the most suitable for compounding rubber and plastic solids ?
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A. Pug mill

B. Banbury mixer

C. Charge can mixer

D. Pan mixer

182. At low Reynolds number, the power (P) required for agitating a fluid in a stirred tank becomes independent of inertial forces. In this limit, indicate which of the following relations is satisfied: Po = ?/?N3 D5: Power number Re = ? N D2/?: Reynolds number N is the impeller rotational speed, and D is the impeller diameter ?
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A. Po ? Re-1.0

B. Po ? Re0.0

C. Po ? Re0.5

D. Po ? Re1.0

183. Which of the following is not a cutting machine ?
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A. Tube mills

B. Knife cutters

C. Slitters

D. Dicers

184. Pick out the material having minimum Rittingers number?
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A. Calcite

B. Quartz

C. Pyrite

D. Galena

185. Vertical transportation of materials can be done by a/an_______________?
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A. Apron conveyor

B. Pneumatic conveyor

C. Bucket elevator

D. Both B. & C.
186. Which is a secondary crusher for a hard & tough stone ?
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A. Toothed roll crusher

B. Impact crusher

C. Cone crusher

D. Jaw crusher

187. For achieving maximum capacity of the ball mill, the ball charge should be equal to about ______________ percent of the ball mill volume?
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A. 25

B. 50

C. 10

D. 75

188. Optimum ratio of operating speed to critical speed of a trommel is_____________________?
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A. 0.33-0.45

B. 1.5-2.5

C. 1.33-1.45

D. 0.5-2

189. Froth floatation is the most suitable for treating ____________________?
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A. Quartzite

B. Iron ores

C. None of these

D. Sulphide ores
190. A filter press is___________________?
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A. Not suitable for wide range of materials under varying operating conditions of cake thickness

B. pressure

C. A batch filter

D. Not suitable, if the liquid is the main product

E. Having prohibitively high maintenance cost

191. Which of the following is a vacuum filter ?
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A. Tank filter (Nutsche filter)

B. Filter press

C. Rotary disc filter

D. Batch basket centrifuge

192. Cement clinker is reduced to fine size by a _____________________?
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A. Ball mill

B. Roll crusher

C. Hammer mill

D. Tube mill
193. Mixing of plastic solids is generally facilitated by___________________?
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A. Mastication

B. None of these

C. Dispersion

D. Kneading
194. What is the usual value of angle of nip for crushing of ordinary rock in smooth steel crushing rolls?
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A. 46

B. 40

C. 32

D. 16

195. For laminar flow of filtrate through the cake deposited on septum, which of the following will be valid ?
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A. Kozeny-Carman equation

B. Levas equation

C. None of these

D. Blake-Plummer equation

196. Addition of filter aid to the slurry before filtration is done to _______________ of the cake?
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A. Increase the porosity

B. Decrease the compressibility co-efficient

C. Decrease the porosity

D. Increase the compressibility co-efficient

197. The main differentiation factor between tube mill and ball mill is the ___________________?
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A. Size of the grinding media

B. Operating speed

C. Final product size

D. Length to diameter ratio
198. Sphericity of pulverised coal is__________________?
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A. 1

B. ?

C. > 1

D. < 1
199. Mesh indicates the number of holes per_________________?
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A. Square inch

B. Linear inch

C. Square foot

D. Linear foot

200. With increase in the capacity of screens, the screen effectiveness__________________?
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A. Decreases exponentially

B. Increases

C. Remains unchanged

D. Decreases