Rigorous modeling of reactive absorption processes

Absorption of gases in liquid solutions accompanied by chemical reactions, or reactive absorption, represents one of the most important industrial operations. The advantages of this process are enhanced solution capacity, low impurity concentrations up to the ppm range, moderate operation pressure, and selective removal of contaminants. Reactive absorption is based on a combination of various kinetically controlled phenomena, the focus being on the coupling of chemical reactions and mass transfer in multicomponent mixtures. Therefore, the process description using the equilibrium concept is often insufficient and kinetic modeling is required. This paper describes the basics of rigorous modeling of reactive absorption processes. Several case studies are used in order to validate the models. In addition, a discussion of necessary model parameters, like diffusion coefficients and reaction kinetics, is given. A reduced model with lower computation time is obtained via detailed sensitivity analysis. This model is successfully used in dynamic simulations. In this respect, a proper consideration of the film reactions appears to be crucial.