Experimental investigations of liquid velocity distributions and power input in a jet-loop reactor have been carried out on a semi-industrial scale. The effect of solids concentrations on the liquid velocity distributions and the power input in the reactor is determined. It was found that solids reduce liquid flow velocity along the draft tube by 30%. Profiles of liquid velocity are flattened due to the presence of solids but dependent on the particle size. This effect increases with the decrease of the particle diameter and with the increase of the liquid flow rate. Radial velocity profiles are described by Schlichting's correlation. Power input is found to increase slightly with the solids concentration.