In mechanically agitated gas-liquid contactors design, transport characteristics such as volumetric mass transfer coefficients, power input, and gas hold-up often become the key parameters. Therefore, their values should be estimated as precisely as possible. The power input is usually used as the scale of energy dissipation for other characteristics. The goal of this work is to establish reliable power input correlations for industrial processes design, where the coalescent batch is used. The experiments were carried out in a pilot-plant and laboratory vessel. Different types of impellers, as well as their different diameters, were used, and also the combinations of radially and axially pumping impellers on a common shaft. Energy consumption was measured in a multi-impeller vessel with different impeller frequencies and several gas flows. Correlation equations describing the behavior of individual impellers were evaluated. The correlations we suggested can be used for impeller power prediction in industrial scale vessels under a wide range of operational conditions. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.