92. 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
93. 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
94. 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
95. 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
96. Laminar flow range of mixing speed is obtained for
A.Rei<10
B.10
D.None of these
97. Which of the following number is calculated from the diameter and peripheral speed of the impeller?
A.Reynolds number
B.Froude number
C.Power number
D.None of these
98. A higher liquid height will lead to a higher gas hold up by which the oxygen transfer rate will be
A.higher throughout the reactor
B.lower throughout the reactor
C.higher at the base of the reactor
D.lower at the base of the reactor
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