logo

CuriousTab

CuriousTab

Discussion


Home Biochemical Engineering Agitation and Aeration Comments

  • Question
  • An increase in the heat transfer in the stirred tank reactor will be observed at


  • Options
  • A. higher cooling water temperature
  • B. higher stirrer speed
  • C. the removal of baffles from the reactor
  • D. slower stirrer speed

  • Correct Answer
  • higher stirrer speed 


  • Agitation and Aeration problems


    Search Results


    • 1. Oxygen transfer rate is increased with an increase in the stirrer speed in aerated bioreactor because

    • Options
    • A. it decrease the bubble size
    • B. it decreases the size of the boundary layer surrounding a bubble
    • C. it increases the rate of movement of oxygen molecules through the bulk liquid
    • D. all of the above
    • Discuss
    • 2. In a tall reactor, oxygen transfer rates will be

    • Options
    • 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
    • Discuss
    • 3. A higher liquid height will lead to a higher gas hold up by which the oxygen transfer rate will be

    • Options
    • 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
    • Discuss
    • 4. The main function of the dimples provided in the cooling jacket is to

    • Options
    • A. increase the level of turbulence of the cooling water in the jacket
    • B. increase the residence time of the cooling water in the jacket
    • C. increase the cooling water-jacket wall boundary layer size
    • D. all of the above
    • Discuss
    • 5. Which of the following number is calculated from the diameter and peripheral speed of the impeller?

    • Options
    • A. Reynolds number
    • B. Froude number
    • C. Power number
    • D. None of these
    • Discuss
    • 6. For laminar flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Rei is Reynolds number for agitator; Di, stirrer diameter and N, stirrer speed)

    • Options
    • A. Np = K(Rei)-1
    • B. Np = N2Di(Rei)-1
    • C. Np = K(Rei)
    • D. Np = KNDi(Rei)-2
    • Discuss
    • 7. Which of the following impellers generate a flow parallel to the axis of shaft?

    • Options
    • A. Axial flow
    • B. Radial flow
    • C. Both (a)and(b)
    • D. None of these
    • Discuss
    • 8. What is the effect of the concentration of dissolved salts and sugars on the oxygen transfer rate?

    • Options
    • 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
    • Discuss
    • 9. The power required by an agitator operating in a gas-sparged system is

    • Options
    • A. lesser than the power required by an impeller in operating at same speed in a gas free system
    • B. more than the power required by an impeller in operating at same speed in a gas free system
    • C. same as the power required by an impeller in operating at same speed in a gas free system
    • D. none of the above
    • Discuss
    • 10. Laminar flow range of mixing speed is obtained for

    • Options
    • A. Rei<10
    • B. 10<Rei<104
    • C. Rei>104
    • D. None of these
    • Discuss


    Comments

    There are no comments.

Enter a new Comment