Numerical simulations of the effect of liquid viscosity on gas-liquid mass transfer of a bubble column with a CFD-PBM coupled model

It is important to understand the gas-liquid mass-transfer performance for the reactor design and scaleup of bubble columns. Air-water bubble columns have been extensively simulated, however the simulation of bubble columns with often used high-viscosity liquids are limited. Here, the CFD-PBM coupled model was developed to simulate the mass transport characteristics in a bubble column with liquid viscosity from 1.0 to 39.6 mPa s and superficial gas velocity from 0.02 to 0.3 m/s. The gas-liquid interfacial area a was estimated from the simulated local gas holdup and bubble size distribution. Two typical theoretical mass transport models were used to calculate the liquid-side mass transfer coefficient k(l). The volumetric mass transfer coefficient k(l)a, calculated from a and k(l), significantly decreased with increasing liquid viscosity. Overall, the coupled model accurately predicted the effect of liquid viscosity on mass transport in a wide liquid viscosity. (C) 2020 Elsevier Ltd. All rights reserved.