Bubble columns with fine pore sparger and non-Newtonian liquid phase: Prediction of gas holdup

In this work we study the performance of a bubble column equipped with metal porous sparger when the liquid phase is a shear-thinning non-Newtonian fluid. The aim is to formulate a generalized correlation that can be applied for predicting the average gas holdup in this kind of bubble columns. By conducting experiments using several non-Newtonian shear thinning fluids, the average gas holdup as well as the initial bubble size distribution were measured. By CFD simulations a mean shear rate and consequently the corresponding effective liquid viscosity is estimated as a function of the gas flow rate. The calculated viscosity together with other physical properties and geometrical parameters is used in a correlation based on dimensionless groups, which was proved capable of predicting the gas holdup with reasonable accuracy (±10%).