Browsing by Author "Arias, Ana Marisa"

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    Aplicación del enfoque de ingeniería de reacción (REA) para modelar el secado de orujos por convección.
    (2021-10) Bonfigli, Mónica Beatriz; Arias, Ana Marisa; Mores, Patricia Liliana; Benz, Sonia Judith; Scenna, Nicolás José; Masciarelli, Roque
    La bioeconomía es una alternativa para afrontar la demanda de alimentos y energía para una población en crecimiento y además mitigar los impactos adversos sobre el medio ambiente y los recursos naturales que originan su producción. Incluye el aprovechamiento de desechos de procesos industriales para la generación de bioproductos con valor agregado, como los que pueden obtenerse a partir de orujo de uva. En los procesos de obtención, la operación de secado es fundamental y un buen modelo es importante para el diseño del secadero y la evaluación de su rendimiento. El objetivo de este trabajo es utilizar el enfoque de ingeniería de reacción (REA), una técnica simple pero precisa, para modelar el secado de orujos por convección. La curva de energía de activación normalizada, obtenida a partir de una experiencia a 100 °C se utilizó para predecir la cinética de secado y los perfiles de temperatura a 60 °C. El REA demostró capturar adecuadamente la física del proceso. El coeficiente de determinación (R2) se determinó en 0,996 y 0,997 (en promedio) para predecir la temperatura y el contenido de humedad, respectivamente. La principal ventaja es que se requiere una única experiencia minuciosa para generar la curva de energía de activación normalizada y luego utilizarla para predecir otros contenidos de humedad y perfiles de temperatura del material. Este modelo puede utilizarse para proyectar la operación en otras condiciones e implementarse fácilmente para diseñar nuevas instalaciones de secado u optimizar las existentes.
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    Cost-based comparison between membrane systems and chemical absorption processes for CO2 capture from flue gas.
    (2019-05-09) Arias, Ana Marisa; Mores, Patricia Liliana; Scenna, Nicolás José; Caballero, José Antonio; Mussati, Miguel Ceferino; Mussati, Sergio Fabián
    An optimization study of membrane-based separation systems for carbon dioxide capture from flue gas of power plants is conducted, considering the possibility of employing up to four stages and using diverse options to create the required driving force. By proposing a superstructure-based model, the number of stages, recycle options, use of feed compression and/or permeate vacuum, driving force distribution along each membrane stage, operating conditions and equipment sizes are simultaneously optimized in order to minimize the total annual cost at high capture ratios and purity targets. Thus, different optimal arrangements are obtained and the total cost is reduced in about 20% compared without employing vacuum. Besides the optimal number of stages diminishes with decreasing purity, but it is independent of the capture ratio. Also, the total cost decreases with the increase of the membrane permeance requiring lower values of operating pressure and membrane areas. Permeance values higher than 2400 GPU lead to lower number of stages and recycles for the same separation target. By contrast, a sensitivity analysis shows that the total cost increases with the increase of the electricity price, capacity factor, and capital recovery factor, which are the more influential parameters in the objective function. Despite new optimal operating and design conditions are obtained when these parameters vary, no modifications in the optimal arrangement are observed.
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    Membrane superstructure optimization for carbon capture from cement plants. Water content influence on optimal solution.
    (2023) Arias, Ana Marisa; Scenna, Nicolás José; Mores, Patricia Liliana
    A four-membrane superstructure, embedding different connection alternatives and driving force generation options, was extended to consider a four-component wet flue gas mixture. Three case scenarios were assessed for treating a flue gas stream from a cement plant. By minimizing the specific total annual cost (sTAC), each case converged to a distinct local optimal arrangement, achieving the same separation target (90% CO2 recovery and 95% CO2 purity on the concentrated stream), thus highlighting the versatility of the model. In terms of the same superstructure and cost model, the optimal solution for capturing CO2 from wet flue gases is approximately 1.5 times higher than that of a dry mixture. A commonly published optimal two membrane-stage configuration fails to achieve high separation targets, even with low water content. The most cost-effective approach is to eliminate water at the beginning of the process. The energy consumed for CO2 pumping and compression is offset by energy generated during retentate expansion, resulting in a surplus that reduces the overall energy consumption to drive the process.
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    Membrane-based processes: optimization of hydrogen separation by minimization of power, membrane area, and cost.
    (2018-11-12) Mores, Patricia Liliana; Arias, Ana Marisa; Scenna, Nicolás José; Caballero, José Antonio; Mussati, Sergio Fabián; Mussati, Miguel Ceferino
    This work deals with the optimization of two-stage membrane systems for H2 separation from off-gases in hydrocarbons processing plants to simultaneously attain high values of both H2 recovery and H2 product purity. First, for a given H2 recovery level of 90%, optimizations of the total annual cost (TAC) are performed for desired H2 product purity values ranging between 0.90 and 0.95 mole fraction. One of the results showed that the contribution of the operating expenditures is more significant than the contribution of the annualized capital expenditures (approximately 62% and 38%, respectively). In addition, it was found that the optimal trade-offs existing between process variables (such as total membrane area and total electric power) depend on the specified H2 product purity level. Second, the minimization of the total power demand and the minimization of the total membrane area were performed for H2 recovery of 90% and H2 product purity of 0.90. The TAC values obtained in the first and second cases increased by 19.9% and 4.9%, respectively, with respect to that obtained by cost minimization. Finally, by analyzing and comparing the three optimal solutions, a strategy to systematically and rationally provide ‘good’ lower and upper bounds for model variables and initial guess values to solve the cost minimization problem by means of global optimization algorithms is proposed, which can be straightforward applied to other processes.
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    Optimal design of a two-stage membrane system for hydrogen separation in refining processes.
    (2018-10-31) Arias, Ana Marisa; Mores, Patricia Liliana; Scenna, Nicolás José; Caballero, José Antonio; Mussati, Sergio Fabián; Mussati, Miguel Ceferino
    This paper fits into the process system engineering field by addressing the optimization of a two-stage membrane system for H2 separation in refinery processes. To this end, a nonlinear mathematical programming (NLP) model is developed to simultaneously optimize the size of each membrane stage (membrane area, heat transfer area, and installed power for compressors and vacuum pumps) and operating conditions (flow rates, pressures, temperatures, and compositions) to achieve desired target levels of H2 product purity and H2 recovery at a minimum total annual cost. Optimal configuration and process design are obtained from a model which embeds different operating modes and process configurations. For instance, the following candidate ways to create the driving force across the membrane are embedded: (a) compression of both feed and/or permeate streams, or (b) vacuum application in permeate streams, or (c) a combination of (a) and (b). In addition, the potential selection of an expansion turbine to recover energy from the retentate stream (energy recovery system) is also embedded. For a H2 product purity of 0.90 and H2 recovery of 90%, a minimum total annual cost of 1.764 M$·year−1 was obtained for treating 100 kmol·h−1 with 0.18, 0.16, 0.62, and 0.04 mole fraction of H2, CO, N2, CO2, respectively. The optimal solution selected a combination of compression and vacuum to create the driving force and removed the expansion turbine. Afterwards, this optimal solution was compared in terms of costs, process-unit sizes, and operating conditions to the following two suboptimal solutions: (i) no vacuum in permeate stream is applied, and (ii) the expansion turbine is included into the process. The comparison showed that the latter (ii) has the highest total annual cost (TAC) value, which is around 7% higher than the former (i) and 24% higher than the found optimal solution. Finally, a sensitivity analysis to investigate the influence of the desired H2 product purity and H2 recovery is presented. Opposite cost-based trade-offs between total membrane area and total electric power were observed with the variations of these two model parameters. This paper contributes a valuable decision support tool in the process system engineering field for designing, simulating, and optimizing membranebased systems for H2 separation in a particular industrial case; and the presented optimization resultsprovide useful guidelines to assist in selecting the optimal configuration and operating mode.
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    Optimization of revalorization process from wine industry residual biomass.
    (Asociación Argentina de Ingenieros Químicos/ Oscar Pagola, 2023-06) Bonfigli, Mónica Beatriz; Orellano, Santiago; Arias, Ana Marisa; Scenna, Nicolás José; Mores, Patricia Liliana
    The large quantities of residual biomass generated by agro-industries represent important resources for new value chains with strong industrial potential. The circular vision of bioeconomy promotes the revalorization of these wastes by obtaining biofuels and bioproducts with high added value. Despite the significant evolution observed in the last decades, and an increasing volume of related patents, circular bioeconomy research is not yet significantly mirroredby the market, showing that its full potential is still far from being reached. Grapes are one of the most widely grown fruits throughout the world. A significant amount of solid waste is generated mainly composed of grape pomace, whichcan represent more than 20% of the biomass harvested and processed. Grape pomace is a low-value by-product that contains a significant quantity of useful components that could be employed as food ingredients, chemicals, and biofuels. The successful recovery of these compounds would not only reduce the generated pollutants, but would also contribute to the sustainable development and economic competitiveness of the wine industry. In this context, the objective of this work is to analyze the recovery process of bio-active compounds from by-products of the wine industry and to optimize two variables of interest a) total extraction yield and b) the required fresh solvent flow, from the definition of different objective functions through mathematical modelling. The effect of the quantity of raw material to process, its moisture content and the extraction temperature on the mentioned variables was studied. The implemented non-linear program (NLP) was not oriented to explore optimal structural alternatives (process synthesis), but to optimize the different operating variables against different optimization scenarios, fulfilling the proposed restrictions. The proposed process configuration is based on a standard structure for this type of extractive plants. It consists of a tunnel dryer, a crusher, extractors, intermediate storage tanks, a film evaporator, a heat exchanger and pumps. The optimization model was solved for different alternatives in order to explain the effect of a range of operating conditions and volume of each leaching tank to achieve at least given percentage of anthocyanin extraction with a minimum solvent requirement. The solutions of the analyzed alternatives adequately represent the trade-offs between the total extraction yield and required solvent. As a result, an increase in solvent consumption with the increase in extraction yield is observed. The energy consumed in the evaporator is proportional to the quantity and quality of the product, as well as to the quantity of recovered solvent, which reduces the consumption of fresh solvent for a given feed value. These results are promising, and set the base for future studies such as the design and selection of operation mode, exploring different configuration alternatives.
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    Reducción de las emisiones de gases con efecto invernadero (GEIs) en el sector energético mediante tecnologías no convencionales
    (2017-03-27) Arias, Ana Marisa; Mussati, Sergio Fabián; Scenna, Nicolás José
    Históricamente, en la provincia de Santa Fe las demandas de electricidad se satisfacen importando energía generada en otras provincias ya que carece de una matriz energética propia. Se conoce que en Argentina el 52 % de la electricidad se produce en centrales térmicas, que funcionan a gas o diesel; el 43 % en usinas hidroeléctricas, y apenas el 4 % es energía nuclear. A partir del año 2003 las demandas eléctricas en la mayoría de las provincias, incluyendo Santa Fe, se incrementaron fuertemente como consecuencia del crecimiento económico experimentado en diferentes sectores productivos tales como el agro, la construcción y la industria. Esto obligó tanto al gobierno nacional como provincial a impulsar un nuevo plan estratégico con el principal objetivo de aumentar la producción de electricidad y así poder reducir los efectos negativos de la crisis energética que afecta a todo el territorio nacional. A pesar de que las centrales de ciclo combinado operan con gas natural y en consecuencia son las que menos contaminan respecto a plantas que operan con carbón, requieren que los gases de combustión generados deban ser tratados necesariamente antes de ser emitidos al ambiente. La corriente de gases exhaustos contiene uno de los principales responsables del calentamiento global, el CO2. Diferentes estudios revelan que para las próximas décadas la concentración de CO2 en el ambiente aumentaría a ritmos más acelerados en caso que no se adopten las medidas y acciones necesarias tendientes a disminuir dichas emisiones. De este modo resulta evidente la imperiosa necesidad de investigar y proponer soluciones efectivas para reducir las emisiones de gases con efecto invernadero. Algunas de las acciones tendientes a reducir las emisiones de CO2 procedentes de la combustión de combustibles fósiles para la producción de energía, debieran apuntar a: 1) uso racional de la energía generada (aumento de la eficiencia en los procesos de conversión), 2) utilizar combustibles que tengan menores emisiones (energías renovables, gas natural), 3) captura y almacenamiento del CO2 procedente de la combustión. En este sentido, esta tesis se enmarca en el punto 3) ya que se propone investigar y desarrollar procesos eficientes para tratar las emisiones generadas en las plantas de producción de energía eléctrica que contribuyen al efecto invernadero, en especial el CO2.
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    Secado por convección de desechos industriales susceptibles de revalorización: modelado matemático y validación a través de la aproximación a la Ingeniería de las Reacciones.
    (Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria, 2022-04) Bonfigli, Mónica Beatriz; Arias, Ana Marisa; Mores, Patricia Liliana; Benz, Sonia Judith; Scenna, Nicolás José
    La bioeconomía circular surge como un nuevo paradigma productivo donde la clave es la sostenibilidad en el uso de los recursos. En él se entrelazan los principios de la economía circular, donde un producto no se considera un residuo al final de su vida útil, y de la bioeconomia que trata sobre la biologización de la creación de valor industrial. Este paradigma aboga por el uso continuo de recursos, sugiriendo la mejora de la durabilidad de equipos, instalaciones e infraestructura, así como la revalorización de desechos para otros procesos industriales. El orujo de uva y la okara de soja son subproductos de bajo valor comercial que contienen una cantidad importante de componentes valiosos de los que pueden obtenerse productos con valor agregado. Su generación masiva y su perecibilidad debido al contenido de humedad hacen necesaria la operación de secado. Para obtener el producto final deseado con la menor demanda energética posible, es indispensable estudiar las condiciones y cinética de secado. A partir de dicho análisis se determina el tiempo de secado que afecta directamente el tamaño de los equipos y también proporciona información para optimizar el rendimiento de los secaderos existentes. La aproximación a la ingeniería de las reacciones (REA) es un modelo matemático semi-empírico para predecir la evolución higrotérmica durante el secado. La energía de activación relativa es el parámetro característico de la REA, que describe los cambios de comportamientos internos dentro de los materiales durante el secado. Este parámetro es independiente de las condiciones de operación, se genera a partir de una experiencia de secado precisa y se combina con la energía de activación de equilibrio para producir una relación única. Esta característica le otorga al modelo la capacidad de predicción en una amplia gama de condiciones. El objetivo de este trabajo es implementar y evaluar la eficacia de la REA para modelar el secado por convección de orujos de uva y okara de soja. Los resultados del modelo se comparan con datos experimentales. Las curvas de energía de activación normalizada, obtenidas a partir de los datos experimentales a 60 °C para los orujos y a 50 °C para la okara se utilizaron para predecir los perfiles de humedad y temperatura a otras condiciones de secado: 70, 80 y 90 °C para los orujos y 60 y 70 °C para la okara. La REA demostró capturar adecuadamente la física del proceso. Los perfiles de contenido de humedad y temperatura concuerdan muy bien con los datos experimentales, respaldados por R2 superiores a 0.971 para la humedad y 0.988 para la temperatura. El modelo REA resulta un modelo robusto y efectivo para describir el proceso de secado, debido a su predictibilidad y su capacidad de extrapolación en un amplio rango de temperaturas. Es una opción apropiada para ahorrar tiempo y recursos computacionales. Esto es importante si se piensa en optimización de procesos complejos en los cuales el secado es solo una de las operaciones involucradas.
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    Water influence on total annual cost for CO2 separation through a two-stage membrane system.
    (Asociación Argentina de Ingenieros Químicos/ Oscar Pagola, 2023-06) Arias, Ana Marisa; Kraft, Romina Alejandra; Scenna, Nicolás José; Mores, Patricia Liliana
    Carbon capture remains as one of the most promising alternatives to mitigate flue gas impact from installed plants. Several alternatives are being studied with different development levels. Membranes have been employed for gas separation in diverse industries; its application for carbon capture has been largely discussed. The mayor drawback of this technology lies on the high-energy requirement for driving force generation and its liability when treating humid gas. As a first approach to CO2 separation, early works study binary gas mixtures as representative of flue gases. However, the presence of a little amount of H2O may affect the separation in ways that need to be explored. In this work, an analysis on the impact of H2O presence on the driving force and overall separation efficiency is carried out. A four- component flue gas mixture including H2O and 02 is considered for a more realistic approach. The process objective is to recover 90% of the incoming CO2 and deliver a high purity permeate. Here, a typical two-stage counter-current membrane system is studied (Figure 1). Each stage includes a feed compressor followed by a cooler, the first one is also connected to a vacuum pump on the permeate side and another cooler. An optimization program based on a previous model [1] modified to consider a four-component mixture is implemented in GAMS. Mass and energy transfer phenomena, investment and operative costs, among others, are represented by a set of algebraic equations. Three different driving force generation setups are considered: feed compression, permeate vacuum, or a combination of both. Total annual cost (TAC) is selected as objective function to assess all the trade-offs between investment and operative costs, contrasting and accounting H2O influence. The resulting optimal driving force generation strategy includes a combination of feed compression and permeate vacuum pumping, fulfilling a 90% CO2 recovery. In fact, the incidence of investment over TAC is much less pronounced than the costs related to energy consumption.