All Free Chemical Engineering MCQs with Answers
Every Chemical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
6,983 questions · page 257 of 350
- A. Salting
- B. Scaling
- C. Viscous
- D. Foamy
Explanation: Long-tube vertical evaporators are particularly suitable for foaming liquors because the liquor travels rapidly through the tubes and…
Correct answer: Foamy- A. Horizontal tube evaporator
- B. Short tube vertical evaporator
- C. Long tube vertical evaporator
- D. None of these
Explanation: In a horizontal-tube evaporator, heating steam condenses inside the horizontal tubes while the liquor flows over the outside surfaces.
Correct answer: Horizontal tube evaporator- A. Low corrosiveness
- B. High specific heat
- C. Low dirt factor
- D. Low viscosity
Explanation: Water removes substantial heat because its specific heat is high, so a relatively large amount of energy is absorbed for each degree of…
Correct answer: High specific heat- A. 0.5 to 0.8
- B. 0.25 to 0.50
- C. 0.05 to 0.15
- D. 0.8 to 0.9
Explanation: Rotary dryers normally operate with a small fraction of their internal volume occupied by solids, commonly about 0.05 to 0.15.
Correct answer: 0.05 to 0.15- A. Both A. & B.
- B. difference
- C. Economic limit reached, when the plant cost exceeds the saving of steam
- D. Practical limit reached, due to low heat transfer rate because of inadequate temperature
- E. Neither A. nor B.
Explanation: Adding effects eventually gives too little temperature difference per effect, reducing heat-transfer rates, while the extra equipment also…
Correct answer: Both A. & B.- A. G0.8
- B. G0.5
- C. G0.2
- D. G1.5
Explanation: For turbulent flow in tubes, standard correlations such as Dittus-Boelter contain the mass-velocity term approximately to the 0.8 power.
Correct answer: G0.8- A. 0.99
- B. 0.95
- C. 0.80
- D. 0.55
Explanation: A correction factor below about 0.80 indicates an inefficient exchanger arrangement and a rapidly declining temperature-driving force.
Correct answer: 0.80- A. 2
- B. ½
- C. 8
- D. 4
Explanation: In a 1–2 exchanger, splitting the tubes into two passes approximately doubles the tube velocity, making friction loss about four times…
Correct answer: 8- A. Baffle spacing
- B. Clearance
- C. Pitch
- D. None of these
Explanation: Shell-side cross-flow area is determined from the shell diameter, baffle spacing, tube pitch and tube-to-tube clearance.
Correct answer: None of these- A. Height is 25% of the I.D. of the shell
- B. Height is 75% of the I.D. of the shell
- C. Spacing is 75% of its height
- D. Width is 25% of its height
Explanation: A 25 percent segmental baffle cut means that 25 percent of the shell diameter is removed from the baffle.
Correct answer: Height is 75% of the I.D. of the shell- A. O.D. of the tube for square pitch
- B. Shortest distance between two adjacent tube holes
- C. Shortest centre to centre distance between adjacent tubes
- D. None of these
Explanation: Tube pitch is measured from the centre of one tube to the centre of the adjacent tube, using the shortest centre-to-centre distance.
Correct answer: Shortest centre to centre distance between adjacent tubes- A. More
- B. Same
- C. Twice
- D. Less
Explanation: Triangular pitch gives greater shell-side turbulence and a larger heat-transfer coefficient than square pitch under comparable conditions.
Correct answer: Less- A. 2.5 metres
- B. 6 metres
- C. 10 metres
- D. 0.5 metre
Explanation: Heat-exchanger tubes are commonly manufactured in practical lengths such as 2.5 and 6 m, while 10 m tubes are generally too long for usual…
Correct answer: 10 metres- A. Characteristic of process fluid
- B. All A., B. and C.
- C. Suspended solids in the fluid
- D. Velocity of process fluid containing suspended solids
Explanation: Fouling depends on the fluid characteristics, the concentration of suspended solids, and their velocity because these factors control…
Correct answer: All A., B. and C.- A. 1000
- B. 3000
- C. 5000
- D. 10000
Explanation: Entrance and developing-flow effects influence the inside film coefficient at lower Reynolds numbers, but their effect becomes negligible…
Correct answer: 10000- A. 1250
- B. 2500
- C. 7500
- D. 15000
Explanation: Condensing steam provides a high heat-transfer coefficient, and for ordinary design conditions a value near 7500 kcal/(h·m²·°C) is…
Correct answer: 7500- A. Layout
- B. Both A. & B.
- C. Pitch
- D. Neither A. nor B.
Explanation: Shell-side velocity is affected by the free flow area between tubes. Changing tube layout or tube pitch changes this area, so either…
Correct answer: Both A. & B.- A. 3-5
- B. 8-15
- C. 5-11
- D. 12-18
Explanation: The minimum carbon-steel shell thickness of a shell-and-tube exchanger increases with shell diameter and commonly falls in the approximate…
Correct answer: 5-11- 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.
Explanation: Triangular pitch places tubes more closely than square pitch, so more tubes fit within the same shell diameter.
Correct answer: Permits the use of more tubes in a given shell diameter- A. √(2d)
- B. √d
- C. √(2πd)
- D. d
Explanation: The equivalent diameter is 4A/P, where A is flow area and P is wetted perimeter. For a square duct, 4(d²)/(4d) equals d.
Correct answer: d