Mathematical modeling and optimization of carbon dioxide stripping tower in an industrial ammonia plant

Abstract

In the present study, performance of an industrial regeneration tower has been examined and validated for stripping of carbon dioxide from diethanolamine (DEA)-promoted hot potassium carbonate solution. The applied model employs a comprehensive non-linear rate-based method to take into account the coupling between material and energy balances, thermodynamic vapor-liquid equilibrium (VLE) relations and chemical kinetics. VLE relations are used to model the flash section located on the top of tower. The penetration theory provides an appropriate desorption rate and enhancement factor for the chemical desorption which incorporates an extensive set of important reactions. The model predictions were compared with the operating data obtained from ammonia plant of a petrochemical complex. The impact of parameters such as steam temperature, potassium carbonate concentration, inlet temperature of rich solution, promoter concentration and column pressure on the tower performance have been examined and optimized. Acceptable agreements have been attained between the simulation and measured industrial data. The optimum conditions were found to be 2.5wt%, 1.6 barg, 401 and 378K for promoter concentration, column pressure, steam temperature, and inlet temperature of rich solution which demonstrate a good compatibility in comparison to optimum operational conditions.