THE INFLUENCE OF GAS AND LIQUID AXIAL-DISPERSION ON DETERMINATION OF KLA BY DYNAMIC METHOD

The dynamic pressure step method, for measuring oxygen transfer rates in aerated, agitated vessels, is analysed from the point of view of error in k(L)a value. The errors incurred by the use of simple models (plug flow and perfect mixing) are estimated with respect to the two-phase axial dispersion model (this model is assumed to be an accurate representation of the gas and liquid mixing in equipment with a large height to diameter ratio). It is shown that the error in k(L)a value with the dynamic pressure step method is several times lower than that for the standard dynamic gassing out technique over a wide range of hydrodynamic conditions.