logo

CuriousTab

CuriousTab

Discussion


Home Biochemical Engineering Agitation and Aeration Comments

  • Question
  • What is/are the major difference(s) between disc and turbine type stirrer?


  • Options
  • A. Blades in disc type are projected out beyond the edge of disc while blades are curved one in turbine type
  • B. Turbine type requires 50 % less air than disc type for the same yield and energy consumption
  • C. Both (a) and (b)
  • D. Number of blades in the stirrer

  • Correct Answer
  • Both (a) and (b) 


  • Agitation and Aeration problems


    Search Results


    • 1. Larger propellers turn at the speed of

    • Options
    • A. 20 to 150 rpm
    • B. 150 to 300 rpm
    • C. 400 to 800 rpm
    • D. 1150 rpm
    • Discuss
    • 2. Froude number is avoided in calculation of power requirements for low viscosity liquid mixing systems when

    • Options
    • A. baffled systems are used
    • B. Reynolds number is less than 300
    • C. both (a)and(b)
    • D. none of these
    • Discuss
    • 3. Monoclonal antibodies are typically produced in fed batch reactors because

    • Options
    • A. hybridoma cells ferment at high maltose concentrations
    • B. hybridoma cells yield higher lactate at high glucose concentrations
    • C. hybridoma cells respire at high glucose concentrations
    • D. none of the above
    • Discuss
    • 4. Yeast is typically produced in fed batch reactors because

    • Options
    • A. yeast cells produce ethanol at low glucose concentrations
    • B. yeast cells ferment at low glucose concentrations
    • C. yeast cells respire at low glucose concentrations
    • D. all of the above
    • Discuss
    • 5. Continuous culture has an advantage over to a batch cultures as

    • Options
    • A. continuous reactors do not need to be shut down and cleaned as regularly as a batch reactor
    • B. most downstream and upstream processes are continuous in nature and thus the operation of continuous bioreactor can be better integrated into the overall manufacturing process
    • C. cells can be maintained at a constant physiological state simply by setting the dilution rate
    • D. all of the above
    • Discuss
    • 6. In the bubble boundary layer, oxygen concentration can be determined by measuring

    • Options
    • A. the steady state oxygen concentration in a mixed aerated reactor before inoculation
    • B. the steady state oxygen concentration in a mixed aerated reactor after inoculation
    • C. the steady state oxygen concentration in the boundary layer using a micro-probe
    • D. volume of oxygen supplied
    • Discuss
    • 7. The addition of antifoams to an aerated bioreactor will decrease oxygen transfer rates because antifoams

    • Options
    • A. increase the tendency of bubbles to coalesce
    • B. tend to accumulate in the gas liquid interface
    • C. reduce the surface tension of the liquid
    • D. All of the above answers
    • Discuss
    • 8. The dynamic technique is based on the

    • Options
    • 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 balance in a fermenter
    • Discuss
    • 9. During aeration, a cylindrical reactor had a height of 10 m. Without aeration, the height was 7.5 m. Under these aeration and mixing conditions, the gas hold up in the reactor is

    • Options
    • A. 100%
    • B. 75%
    • C. 50%
    • D. 25%
    • Discuss
    • 10. A cylindrical reactor has a liquid volume of 100,000 litres. It has an aspect ratio the ratio of the channel height to width of 1:1. The height of the liquid in the reactor will be approximately:

    • Options
    • A. 1.0 m
    • B. 3.0 m
    • C. 5.0 m
    • D. 7.0 m
    • Discuss


    Comments

    There are no comments.

Enter a new Comment