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13 results on '"Arenas, L. F."'

6. Flow Cell Characterisation: Flow Visualisation, Pressure Drop and Mass Transport at 2D Electrodes in a Rectangular Channel.

Author

L. Wu, Arenas, L. F., Graves, J. E., and Walsh, F. C.

Abstract

Aiming to demonstrate the importance and facility of characterising the reaction environment in new commercial laboratory-scale flow cells, fluid flow, pressure drop and space averaged mass transport coefficient were studied in the C-Flow® Lab 5 × 5 cell. A flow-by configuration with smooth, planar electrodes in a rectangular channel was used. Electrolyte mean linear velocities of 2 to 10 cm s−1 past the electrode surface and channel Reynolds numbers of 53 to 265 were considered. The effect of a turbulence promoter next to the working electrode was evaluated. Flow distribution was explored by a qualitative flow visualization study, while the relevance of pressure drop was shown by measurements over the flow channel and the whole cell as a function of mean linear velocity. The electrochemical performance was quantified from the limiting current, permitting the determination of the mass transport coefficient at the electrodes over the same range of flow rates. Reactant conversion in the batch recirculation mode and normalised space velocity were predicted from the electrochemical plug flow reactor design equation. Results were compared to well-characterised electrochemical flow reactors found in the literature. The significance of characterisation techniques and basic reactor models during the development of new processes is emphasised. [ABSTRACT FROM AUTHOR]

Published
2020
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9. Nueva metodología de aprendizaje autónomo aplicada a una práctica de Ingeniería Química mediante técnicas de investigación-acción

Author

Cano Palacios, Mercedes, Vega Borrero, Fernando, Nilsson, Susanna Louise, García Arenas, C., Vilches Arenas, L. F., Leiva, Carlos, Cano Palacios, Mercedes, Vega Borrero, Fernando, Nilsson, Susanna Louise, García Arenas, C., Vilches Arenas, L. F., and Leiva, Carlos

Abstract

Un grupo de profesores del Departamento de Ingeniería Química y Ambiental de la Escuela Técnica Superior de Ingeniería de la Universidad de Sevilla ha realizado un trabajo de investigación-acción con el objetivo de mejorar los resultados docentes en la asignatura Experimentación en Ingeniería Química. El proceso de investigación-acción ha consistido en diseñar una metodología alternativa para una de las prácticas de la asignatura, incorporando un ejercicio de auto-aprendizaje que sustituya a la tradicional metodología aplicada. El objetivo de la experiencia docente pretende conseguir una participación más activa del alumnado, mejorando la asimilación de conceptos y la capacidad para planear el trabajo experimental. Los resultados obtenidos con la nueva metodología, comparados con los del método tradicional de la experiencia, indican que, aunque los alumnos tienden a adoptar una actitud pasiva y son reacios a aumentar el grado de trabajo autónomo, el nuevo procedimiento ayudó a mejorar la aplicación de los conceptos teóricos en el diseño y la realización de la práctica.

Published
2014

10. Application of Zeolitised Coal Fly Ashes to the Depuration of Liquid Wastes

Author

Otal, E., Vilches-Arenas, L. F., Moreno, Natalia, Querol, Xavier, Vale, J., Fernández-Pereira, Constantino, Otal, E., Vilches-Arenas, L. F., Moreno, Natalia, Querol, Xavier, Vale, J., and Fernández-Pereira, Constantino

Abstract

In this study, the application of some zeolitised fly ashes and synthetic zeolites to the decontamination of the leachate produced in a municipal solid waste (MSW) treatment plant and to the liquid waste from a pig farm was analyzed. Thus, the reduction of organic matter (BOD and COD), ammonium and total nitrogen, phosphorus and metals contents after a zeolite treatment was evaluated. Several synthetic zeolites were tested: some commercial zeolites and other synthetic zeolites and zeolitised ashes obtained after a coal fly ash alkaline hydrothermal process. Two forms of contact between the zeolitic material and the liquid waste were tested: in a stirred tank and in a column. In addition, other variables determined were the amount of zeolite and the residence time. The results showed that zeolites, especially zeolitised fly ash, clearly produced a strong reduction in the leachate nitrogen and phosphorus content. q 2004 Elsevier Ltd. All rights reserved.

Published
2005

13. The Importance of Cell Geometry and Electrolyte Properties to the Cell Potential of Zn-Ce Hybrid Flow Batteries

Author

Arenas, L. F., Walsh, F. C., and de León, C. Ponce

Abstract

This paper considers the effects of electrolyte resistivity and inter-electrode gap on the simulated cell potential of an idealized Zn-Ce unit flow cell as a function of applied current density. The thermodynamic, kinetic and ohmic components of cell potential in a redox flow battery (RFB) are taken into account. This is important in the Zn-Ce RFB, where the positive electrode reaction tends to govern cell performance. The ionic conductivity of methanesulfonic acid (MSA) and typical electrolytes reported in the literature was measured as a function of MSA concentration and temperature. At 50°C, the ionic resistivity of the positive and negative electrolytes is 3.0 Ω cm and 4.8 Ω cm respectively, for the most favorable electrolyte composition. The simulated cell potential showed that high surface-area electrodes were beneficial to the cell performance, while electrolytes containing 0.8 mol dm−3Ce(III) and 1.5 mol dm−3Zn(II) produced the lowest ohmic drop, which decreased at higher temperatures. The activation overpotential and internal resistance can be the main potential loss component, depending on electrolyte composition, cell design and electrode materials. The effect of cell geometry on the cell potential was also assessed, larger inter-electrode gaps significantly increasing potential losses.

Published
2016
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