Discuss the factors which influence the selection of impeller design and the amount of power input required for fluid agitation and mixing. Refer to the standard Rushton turbine confuration in your answer. An agitated tank is required to disperse gas in a solution of properties similar to those of water. The tank is 3 m in diameter and a power level of 0.8 kw/m'is chosen. Assume a standard Rushton turbine configuration and fully turbulent conditions. (i)What power is required by the impeller ? (ii)At what speed should the impeller be driven? (iii)If a small pilot scale tank 0.3 m diameter is to be constructed to test the gas dispersion process, at what speed should the impeller be driven ?

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