Discussion
Home ‣ Biochemical Engineering ‣ Agitation and Aeration Comments
- Question
Why vortexing is undesirable in the agitation of biological systems?
Options- A. The collision between the cells, impeller and air bubbles will lead to cell damage
- B. Poor mixing despite the use of high stirrer speeds
- C. Mixing will not be in the turbulent region
- D. All of the above
- Correct Answer
- All of the above
- 1. The reason of using a flat disk in a Turbine is
Options- A. to create high shear conditions
- B. to break up bubbles more efficiently than the impeller blades
- C. to ensure that the bulk of the energy consumption occurs at the blades
- D. all of the above Discuss
- 2. Power consumption by agitation is
Options- A. a function of physical properties
- B. a function of operating conditions
- C. a function of vessel and impeller geometry
- D. all of the above Discuss
- 3. Power number is ratio of
Options- A. imposed forced to intertial force
- B. bouyant force to inertial force
- C. gravitation force to inertial force
- D. imposed force to gravitational force Discuss
- 4. What is the ratio of depth of liquid in vessel to the diameter of tank (H:Dt)?
Options- A. 1 : 1
- B. 2 : 1
- C. 4 : 1
- D. none of these Discuss
- 5. Which of the following best explains the reasons for using axial flow impellers in crystallization and precipitation reactions?
Options- A. Crystal and precipitates are not too small, so as to ensure easy separation of the solids from the mother liquor
- B. Crystals and precipitates are thoroughly broken down, so as to ensure easy separation of the solids from the mother liquor
- C. Both (a) and (b)
- D. Axial flow impellers provide low shear, energy efficient mixing conditions Discuss
- 6. The range of width for the baffle in the fermenter is __________ times of vessel diameter
Options- A. 1/10 to 1/12
- B. 1/8 to 1/10
- C. 1/5 to 1/8
- D. none of these Discuss
- 7. Which of the following(s) is/are non-mechanically agitated reactors?
Options- A. Stirrer tank reactor
- B. Bubble column
- C. Air lift reactor
- D. Both (b) and (c) Discuss
- 8. An aerated bioreactor will increase oxygen transfer rates with the addition of detergents because it
Options- A. enhances bubble coalescence
- B. causes bubbles to expand
- C. discourages bubble coalescence
- D. increases the surface tension of the liquid Discuss
- 9. The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)
Options- A. H = (Zf-Zl)/Zf
- B. H = Zf/Zl
- C. H = Zf/ZfZl
- D. H =(Zf+Zl)/Zf Discuss
- 10. Vortexing in stirred tank reactors can be prevented by
Options- A. installing baffles in the reactor
- B. shifting the impeller to an off-centre position
- C. Both (a) and (b)
- D. using axial flow impellers Discuss
Agitation and Aeration problems
Search Results
Correct Answer: to ensure that the bulk of the energy consumption occurs at the blades
Correct Answer: all of the above
Correct Answer: imposed forced to intertial force
Correct Answer: 1 : 1
Correct Answer: Crystal and precipitates are not too small, so as to ensure easy separation of the solids from the mother liquor
Correct Answer: 1/10 to 1/12
Correct Answer: Both (b) and (c)
Correct Answer: discourages bubble coalescence
Correct Answer: H = (Zf-Zl)/Zf
Correct Answer: Both (a) and (b)
Comments
There are no comments.Programming
Copyright ©CuriousTab. All rights reserved.