Biochemical Engineering - Agitation and Aeration

Exercise :: Agitation and Aeration - Section 3

11. 

In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where Vs and Vt are the superficial gas velocity and bubble rise velocity)

A. H = Vs/(Vs-Vt)
B. H = Vs/(Vs+ Vt)
C. H = Vs/(Vs.Vt)
D. H = (Vs+Vt)/Vs

Answer: Option B

Explanation:

No answer description available for this question. Let us discuss.

12. 

What is the effect of the concentration of dissolved salts and sugars on the oxygen transfer rate?

A. The saturation concentration of oxygen in the medium decreases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate
B. The KLa of the medium decreases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate
C. The KLa of the medium increases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate
D. None of the above

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

13. 

Which of the following impellers generate a flow parallel to the axis of shaft?

A. Axial flow
B. Radial flow
C. Both (a)and(b)
D. None of these

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

14. 

In a tall reactor, oxygen transfer rates will be

A. highest at the surface of the reactor
B. highest at the base of the reactor
C. highest in the middle of the reactor
D. the same throughout the reactor

Answer: Option B

Explanation:

No answer description available for this question. Let us discuss.

15. 

Which of the following impeller is used in situation where strong vertical currents are desirable for suspending heavily particles?

A. Propeller
B. Paddle
C. Turbine
D. None of these

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.