A generalized hydrodynamic model for industrial air-lift reactors has been developed. The model has been adapted to the industrial system with experimental data collected in an air-lift pilot plant operating with water/butanol as the liquid phase. The model calculates liquid circulation velocity and gas hold-up, parameters which are needed for the industrial general air-lift model for performance prediction. Agreement between the hydrodynamic model and pilot experimental points is shown to be fairly good. In addition, measurements of bubble diameter in the water/butanol medium are presented. They are used for interfacial area calculation.