Mixing performance comparison of milliscale continuous high-shear mixers

Abstract

Mixing performance of two continuous flow millilitre-scale reactors (volumes 9.5mL and 2.5mL) equipped with rotor-stator mixers was studied. Cumulative residence time distributions (RTD) were determined experimentally using a step response method. Distributions were measured for both reactors by varying impeller speed and feed flow rate. The mixing effect was determined by measured RTDs. Computational fluid dynamics (CFD) were used to verify that the residence time distribution in the measurement outlet agreed with the outlet flow. The mixing power of both reactors was determined using a calorimetric method. The reactor inlet flow rate was found to affect mixing performance at 1-13s residence times but the effect of impeller speed could not be noted. Both milliscale reactors are close to an ideal continuous stirred-tank reactor (CSTR) at the studied impeller speed and flow rate ranges. The specific interfacial area was found to depend on the reactor inlet flow rate at constant impeller speed for the case of copper solvent extraction.