Dynamic simulation of industrial reactive absorption processes

Accurate dynamic models for industrial reactive absorption processes have to be both rigorous enough in order to reflect the process complexity and simple enough in order to ensure feasibility of process simulations. A comparison of different model approaches revealed that traditional equilibrium stage models and efficiency approaches are inadequate in this context. Therefore, we have developed a new rigorous dynamic two-phase model based on the two-film theory, which serves as a reference description and takes into account the influence of chemical reactions and additional driving forces in electrolyte systems on mass transfer, thermodynamic non-idealities and the impact of structured packings and liquid distributors on the process hydrodynamics. For the model-based control and dynamic on-line simulation some model reductions are required to limit the calculation time for the numerical solution. According to sensitivity study results, simplifications for some physical parameters and a linearisation of the film concentration profiles have been accomplished leading to a reduction of the total number of equations by half. The model has been applied to an industrial sour gas purification process with many parallel and consecutive reversible chemical reactions within a multicomponent system of aqueous electrolytes and validated by pilot plant experiments.