A nonequilibrium stage model of reactive absorption processes has been developed, considering the interactions between reaction and diffusion in the film region. Dynamic and steady-state film models have been incorporated into the process model for low and highly soluble gases respectively. The model was validated against experimental data. The data were obtained from a pilot-plant absorption column in which simultaneous reactive absorption of ammonia and carbon dioxide in aqueous partially carbonated ammonia solution occurred. A comparison between simulation results and the experimental data showed that the model could reasonably predict the process. The model predictions were also compared with those of a process model including enhancement factor. The results indicate that using a film model leads to a more accurate process model than applying enhancement factor.