AbstractGas dispersion in non‐Newtonian fluids is a challenging task due to the formation of large cavities behind the impeller blades, which leads to the generation of very large bubbles. In this study, the effects of impeller speed, impeller type, pumping direction, and CMC concentration on the local and overall gas holdup inside a coaxial mixing tank comprised of two central impellers and an anchor were investigated through tomography, computational fluid dynamics (CFD), and response surface methodology (RSM). The results showed that an increase in the fluid apparent viscosity resulted in decreasing the gas holdup except for the pitched blade impeller in upward‐pumping mode. Although the highest overall gas holdup was accomplished for the downward pumping and co‐rotating mode, the local gas holdup data revealed a non‐uniform distribution of gas by this configuration. The lowest gas dispersion efficiency was achieved by a system comprised of two Scaba impellers and an anchor.