Agitation and Aeration Questions

• Froude number is avoided in calculation of power requirements for low viscosity liquid mixing systems when
• Larger propellers turn at the speed of
• What is/are the major difference(s) between disc and turbine type stirrer?
• In the bubble boundary layer, oxygen concentration can be determined by measuring
• The addition of antifoams to an aerated bioreactor will decrease oxygen transfer rates because antifoams
• The dynamic technique is based on the
• 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
• 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:
• When the height of an aerated bioreactor is increased, it will increase the oxygen transfer rate by
• Power number (Np) is also known as
• Which of the following would be best described as a radial flow impeller?
• Main reason for using baffles in stirred tank reactors are
• Small propellers turn at the speed of either
• A microbial population in a suspension culture will only be limited by oxygen availability if the dissolved oxygen
• 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)
• Higher temperatures affect oxygen transfer rates by
• In the design of a paddle agitator, the ratio of paddle diameter to tank diameter is normally taken as
• The maximum solubility of the alkane in the medium is 5 ppm. If the actual dissolved concentration of the alkane in the medium is 1 ppm. what conclusion may be drawn?
• 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
• The oxygen absorption rate can be determined by