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The modeling, analysis, and simulation validation of an industrial-scale depropenizer column (Refinaria de Capuava, Maua, Saõ Paulo) owned by Petrobras S.A. are carried out using equation-oriented and sequential modular approaches. The model implemented in the equation-oriented environment proved to be suitable for real-time optimization (RTO) applications due to its robustness, fast convergence, and ability to represent the real process. The analysis of the model allows better understanding of the process and establishment of boundaries to process specifications and the parameters updated in the RTO cycle; furthermore, it is shown that feed composition and column pressure drop are critical aspects in the model to represent the actual process.

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Shortcut methods have an important role in the conceptual design of distillation processes because they rapidly provide constraints for important design parameters such as minimum reflux ratio, number of stages, process feasibility, possible splits, and, specifically for extractive distillation, minimum solvent feed ratio and maximum reflux ratio. In this work, a simplified method using reversible distillation models has been applied to the conceptual design of double feed extractive distillation columns. This work uses continuation methods for calculating the curves that determine the feasibility region and all of the resulting design parameters. Combining continuation methods with the column equations yields a simple method for calculating the pinch curves that border the feasibility region. As previously found by other authors, we observed that these extractive distillation pinch curves, in addition to determining the feasibility region, are also useful for calculating an approximate minimum entrainer feed ratio independent of other parameters, as well as accurately pinpointing the minimum and maximum reflux ratios. Applications to example extractive distillation systems allow us to conclude that the method is reliable, fast, and much easier to implement than other methods presented previously in the literature. The systems acetone–methanol–water and ethanol–water–ethylene glycol were employed as case studies, allowing a graphical assessment of the method; however, it can be used in the analysis of systems with more than three components.

ResumenLa celulosa bacteriana es un polímero obtenido por fermentación con microrganismos de los géneros Acetobacter, Rhizobium, Agrobacterium y Sarcina, de las cuales la especie más eficiente es la Acetobacter Xylinum. Este polímero presenta la misma estructura química de la celulosa de origen vegetal, pero difiere en su conformación y propiedades fisicoquímicas, lo que lo hace atractivo para diversas aplicaciones, especialmente en las áreas de alimentos, procesos de separación, catálisis y en medicina, gracias a su biocompatibilidad. Sin embargo, el principal problema es la producción a gran escala limitada por los bajos rendimientos, lo que genera la necesidad de desarrollar alternativas que permitan disminuir o eliminar las causas de esta limitación. En este artículo 1 Ingeniera Química Dr.Ing.