Abstract
Separation of 1,3-butadiene from the C4-cut is not possible by conventional distillation due to formation of several azeotropic mixtures and very close boiling points of the components. The BASF 1,3-butadiene extraction process takes advantage of highly improved relative volatilites of most of the components in the presence of a selective solvent. The solvent is n-methylpyrrolidone (NMP) which contains approximately 8.3% water. In the present work, first, 1,3-butadiene extraction process is simulated in steady-state conditions. The results of the steady-state simulation are compared with plant data and show a good agreement between these values. It was found that the NRTL equation of state is able to predict the experimental data satisfactorily throughout the process. The binary interaction coefficients of the components were tuned in this study such that the equation of state best fits the real equilibrium data. An optimization framework is proposed in this work for a synthesis of extractive distillation sequence, based on a modified genetic algorithm coupled with a sequential process simulator. In the methodology developed here simulation models are automatically generated through a process and are evaluated for various candidate configuration of the system. These candidates are suggested by a genetic algorithm that automatically guides the system towards better solutions.
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