Question: For aerated mixing vessels in an aqueous solution, the mass transfer coefficient (kL) co-relating power consumption (Pm) and fermenter volume (V) can be expressed as [A]. kL ∝ (Pm/V)0.33 [B]. kL ∝ (Pm/V)0.66 [C]. kL ∝ (Pm/V)0.50 [D]. kL…

Question: The dynamic technique is based on the [A]. oxygen material balance in an aerated batch fermenter during the growth of microorganisms [B]. change of the oxygen concentration [C]. oxidation of the sodium sulfite to sodium sulfate [D]. oxygen material…

Question: The oxygen absorption rate can be determined by [A]. sodium sulfite oxidation method [B]. dynamic gassing out technique [C]. direct measurement [D]. all of these Answer: Option D Explanation: No answer description available for this question.

Question: The power required by an impeller in a gas sparged system compare to the power required by impeller operating at same speed in a gas free liquid is usually [A]. lesser [B]. higher [C]. same [D]. may be lesser…

Question: 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 =…

Question: The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively) [A]. H = (Zf-Zl)/Zf [B]. H = Zf/Zl [C]. H = Zf/ZfZl [D]. H =(Zf+Zl)/Zf…

Question: Gas hold up, characterizing the hydrodynamics in a fermenter, mainly depends on the [A]. superficial gas velocity [B]. power consumption [C]. Both (a) and (b) [D]. gas concentration Answer: Option C Explanation: No answer description available for this question.

Question: Surface renewal theory predicts that the mass transfer coefficient is [A]. directly proportional to the square root of the molecular diffusivity [B]. inversely proportional to the square root of the molecular diffusivity [C]. directly proportional to the cube root…

Question: Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (te). The model correlating KL, mass transfer coefficient and DAB, diffusivity can be expressed…

Question: Which of the following model holds correct for the two-film theory? (where KL is the mass transfer coefficient, DAB diffusivity and Zf film thickness) [A]. KL = DAB/Zf [B]. KL = DAB [C]. KL= Zf/DAB [D]. KL = DAB.Zf…