Power and mass transfer correlations for the design of multi-impeller gas-liquid contactors for non-coalescent electrolyte solutions

摘要

Power dissipated and volumetric mass transfer coefficients were measured for single-, double- and triple-impeller configurations of Rushton turbines in the gas-liquid pilot plant vessel of diameter of 0.6 m using a fully non-coalescent (0.5 M Na2SO4) non-viscous batch. Physical relevance of the k_La data measured by the dynamic pressure (DPM) and the classical dynamic methods (CDMs) were tested experimentally and was found that the CDM seriously underestimates the data in the pilot plant vessel for k_La > 0.03 s~(-1). Problems of the measurement and evaluation of physically sound k_La data at high absorption rates in the non-coalescent gas-liquid dispersions are discussed and some consequences of the application of the defective k_La are shown. The DPM was used to measure k_La in the individual sections of the vessel and their mutual differences are explained in terms of exchange liquid flow between sections. Unified correlations of k_La measured in the pilot plant vessel and that measured previously in laboratory vessels (diameter of 0.19 and 0.3 m) were developed and were compared with the data in the literature. The data were most closely fitted by the correlations that include, except of the power dissipated and the gas flow-rate, the circumferential agitator speed.