Artículos en Revistas

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/538

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Author: search.filters.author.Perdomo, Mariano Miguel

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    Estimation of quality variables in a continuous train of reactors using recurrent neural networks-based soft sensors
    (Chemometrics and Intelligent Laboratory Systems, 2024) Perdomo, Mariano Miguel; Clementi, Luis Alberto; Vega, Jorge Rubén
    The first stage in the industrial production of Styrene-Butadiene Rubber (SBR) typically consists in obtaining a latex from a train of continuous stirred tank reactors. Accurate real-time estimation of some key process variables is of paramount importance to ensure the production of high-quality rubber. Monitoring the mass conversion of monomers in the last reactor of the train is particularly important. To this effect, various soft sensors (SS) have been proposed, however they have not addressed the underlying complex dynamic relationships existing among the process variables. In this work, a SS based on recurrent neural networks (RNN) is developed to estimate the mass conversion in the last reactor of the train. The main challenge is to obtain an adequate estimate of the conversion both in its usual steady-state operation and during its frequent transient operating phases. Three architectures of RNN: Elman, GRU (Gated Recurrent Unit), and LSTM (Long Short-Term Memory) are compared to critically evaluate their performances. Moreover, a comprehensive analysis is conducted to assess the ability of these models to represent different operational modes of the train. The results reveal that the GRU network exhibits the best performance for estimating the mass conversion of monomers. Then, the performance of the proposed model is compared with a previously-developed SS, which was based on a linear estimation model with a Bayesian bias adaptation mechanism and the use of Control Charts for decision-making. The model proposed here proved to be more efficient for estimating the mass conversion of monomers, particularly during transient operating phases. Finally, to evaluate the methodology utilized for designing the SS, the same RNN architectures were trained to online estimate another quality variable: the mass fraction of Styrene bound to the copolymer. The obtained results were also acceptable
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    An adaptive soft sensor for on-line monitoring the mass conversion in the emulsion copolymerization of the continuous SBR process
    (Macromolecular Reaction Engineering, 2023) Sanseverinatti, Carlos Ignacio; Perdomo, Mariano Miguel; Clementi, Luis Alberto; Vega, Jorge Rubén
    Soft sensors (SS) are of importance in monitoring polymerization processes because numerous production and quality variables cannot be measured online. Adaptive SSs are of interest to maintain accurate estimations under disturbances and changes in operating points. This study proposes an adaptive SS to online estimate the mass conversion in the emulsion copolymerization required for the production of Styrene-Butadiene rubber (SBR). The SS includes a bias term calculated from sporadic laboratory measurements. Typically, the bias is updated every time a new laboratory report becomes available, but this strategy leads to unnecessarily frequent bias updates. The SS includes a statistic-based tool to avoid unnecessary bias updates and reduce the variability of the bias with respect to classical approaches. A control chart (CC) for individual determinations combined with an algorithmic Cusum is used to monitor the statistical stability of the average prediction error. The adaptive SS enables a bias update only when a loss of said statistical stability is detected. Several bias update methods are tested on a simulated industrial train of reactors for the latex production in the SBR process. The best results are obtained by combining the proposed CC-based approach with a previously developed Bayesian bias update strategy.
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    Impacto de los vehículos eléctricos sobre la red de distribución : análisis bajo distintos modos de operación
    (2022-06) Perdomo, Mariano Miguel; Manassero, Ulises; Vega, Jorge Rubén
    La movilidad eléctrica es una alternativa sustentable que permite disminuir el consumo energético y la emisión de gases contaminantes con respecto a la movilidad convencional. Existen proyecciones que predicen un aumento del uso de vehículos eléctricos. Con esto se crean diversas líneas de estudio relacionadas a inferencias sobre las características de la integración de esta nueva demanda y sobre los efectos que generará en los sistemas eléctricos. Entonces, en el presente trabajo se proponen como principales objetivos: (i) determinar el impacto en la red de una inserción moderada de puntos de recarga públicos; (ii) evaluar el nivel de penetración de EVs de usuarios residenciales para modos de carga (G2V) domiciliaria lenta y semirrápida, según restricciones de variables de operación de la red; y (iii) proponer estrategias de gestión de la recarga controlada y la función dual de carga y aporte de energía a la red de los EVs a través de sus baterías de almacenamiento (V2G). Los resultados obtenidos muestran que la incorporación moderada de puntos de recarga públicos no afecta significativamente la operatividad de la red. Además, se muestra que la recarga controlada de los vehículos eléctricos logra disminuir los impactos negativos en el sistema eléctrico bajo estudio permitiendo mayores niveles de inserción y/o retrasando inversiones en infraestructura eléctrica. Un modo de operación con aporte de energía desde los vehículos eléctricos hacia la red permitiría desplazar generación de punta caracterizada por sus altos niveles de contaminación. Aun así, este modo de operación torna al sistema más susceptible a operar dentro de rangos inadmisibles.