Artículos, conferencias, monografías
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Esta colección está formada por artículos, conferencias, comunicaciones y otras publicaciones elaborados por miembros de la Universitat Politècnica de València.
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Browsing Artículos, conferencias, monografías by Sponsor "Abengoa"
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- PublicationOptimization of chemical cleaning of a reverse osmosis membrane from a desalination plant by means of two step static tests(Taylor & Francis, 2015-09-19) García Fayos, Beatriz; Arnal Arnal, José Miguel; Gimenez Anton, Adria Carles; Alvarez Blanco, Silvia; Sancho Fernández, María Pino; Dpto. de Ingeniería Química y Nuclear; Escuela Técnica Superior de Ingeniería Industrial; Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental; Ministerio de Ciencia e Innovación; Abengoa; Centro para el Desarrollo Tecnológico IndustrialResearch in cleaning procedures of reverse osmosis membranes used in seawater desalination to minimize costs and achieve high efficiency is necessary. Multi-step cleaning can represent a useful tool, since the cleaning efficiency can be improved by means of utilization of different chemicals with complementary cleaning mechanisms. The objective of this work was the optimization of a two-step cleaning procedure to recover the membrane properties and reduce power costs. Spent Hydranautics SWC3 membranes (USA) were supplied by a desalination plant. Cleaning tests were performed in three stages: one-step static cleaning, two-step static cleaning and characterization of the membrane surface after the cleaning process. Four cleaning agents at two different concentrations were used. All possible combinations of them were considered, including sequence effect. After the cleaning process, membrane surface was characterized by field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and atomic force microscopy. One-step static cleaning test indicated that sodium dodecyl sulphate 1% w/v was the most efficient cleaning solution, followed by NaOH 2% w/v. Two-step cleaning tests showed that the procedure that maximized permeate flux recovery was surfactant-alkaline cleaning, whereas the one that maximized the recovery of the salt rejection index was alkaline-acid sequence. Characterization of the membrane surface after the cleaning steps confirmed that fouling deposits were significantly removed.
- PublicationStatic cleaning tests as the first step to optimize RO membranes cleaning procedure(Taylor & Francis, 2015-09-18) García Fayos, Beatriz; Arnal Arnal, José Miguel; Gimenez Anton, Adria Carles; Alvarez Blanco, Silvia; Sancho Fernández, María Pino; Dpto. de Ingeniería Química y Nuclear; Escuela Técnica Superior de Ingeniería Industrial; Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental; Abengoa; Ministerio de Ciencia e InnovaciónMembrane fouling is an intrinsic problem of membrane technology which affects process performance and causes a substantial rise of the operating costs. This becomes central in seawater desalination processes. This study is focused on applying a membrane chemical cleaning protocol to obtain the most adequate cleaning conditions to recover the permselective properties of an irreversibly fouled reverse osmosis membrane from a seawater desalination plant. The research was carried out in three steps: fouling characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy and elemental analysis; static cleaning tests; and characterization of the membrane surface after the cleaning step. The cleaning process was performed in a static way as a preliminary step. Five of the most widely used cleaning agents were tested (NaOH, citric acid, HCl, sodium dodecyl sulfate [SDS], and ethylenediaminetetraacetic acid disodium salt) at a broad range of concentrations and two different temperatures (25 and 40 degrees C). SEM-EDX analysis showed that foulant compounds were mainly silica, iron silicate, and aluminum silicate, which indicated that fouling was mainly colloidal and inorganic. The best cleaning results were achieved by SDS 0.5% w/w at 40 degrees C, as the greatest recovery of the membrane permselective properties (permeability and salt rejection index) was obtained.
- PublicationStudy of ultrasonically enhanced chemical cleaning of SWRO membranes at pilot plant scale(Taylor & Francis, 2017) García Fayos, Beatriz; Arnal Arnal, José Miguel; Gimenez Anton, Adria Carles; Alvarez Blanco, Silvia; Sancho Fernández, María Pino; Dpto. de Ingeniería Química y Nuclear; Escuela Técnica Superior de Ingeniería Industrial; Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental; Abengoa; Ministerio de Ciencia e Innovación; Centro para el Desarrollo Tecnológico Industrial[EN] Fouling accumulated on reverse osmosis (RO) membranes during operation is one of the main problems affecting seawater desalination processes. This phenomenon causes a deterioration of the permselective properties of the membranes, which turns into a loss of performance of the process and costs increase. Conventionally, recovery of the process performance in desalination plants is carried out periodically by means of physical and chemical cleaning stages. However, conventional cleaning does not manage to recover completely the membrane properties and eventually can damage the membrane materials. New membrane cleaning techniques have been developed in order to improve this recovery. Ultrasound (US) radiation, which has shown to be an interesting technique during filtration since it avoids fouling deposition and allows to lengthen the period between cleaning stages, is proposed as an alternative technique to remove membrane fouling. This work investigates the effect of the combination of chemical cleaning methods and US application to clean a RO membrane from a desalination plant. The experiments performed were able to determine the best operating conditions to carry out the US cleaning protocol. Sodium hydroxide 2% w/v and sodium dodecyl sulphate 4% w/v solutions at 25 degrees C were used, as they showed the highest recovery of the membrane properties in the chemical cleaning tests. Results showed that cleaning by US had a positive effect on the membrane selectivity (increase by 15.2%), and a low significant effect on its permeability. The utilization of the chemical cleaning combined with US improved the permeate flux considerably, without modifying salt rejection index in a significant way. Among the two cleaning solutions tested, the best results in terms of permeability and selectivity of the cleaned membrane, were those obtained by the US procedure using NaOH 2% w/v cleaning solution at 25 degrees C.
- PublicationSynthesis of pillared clays from metallic salts as pigments for thermosolar absorptive coatings(Elsevier, 2017) Micó Vicent, Bàrbara; López-Herraiz, María; Bello, Azucena; Martínez, Noelia; Martinez-Verdu, Francisco M.; Abengoa[EN] A general procedure for developing stable solar absorptive coatings at both high temperature and a high solar radiation concentration is presented. In order to generally improve thermal efficiency, a coating with high solar absorptance is applied all over the surface of receiver tubes that is subjected to extreme working conditions. Consequently, a durable coating with high absorptivity for sunlight is needed. An alternative paint formulation research and development line to Pyromark-2500, the paint currently used in many commercial solar thermal power plants (CSP) is proposed. Pigment synthesis is developed by intercalating metallic salts into laminar or tubular clay structures. Metallic pxides, which provide paint with its color properties, are obtained by a calcination process. Addition of silane or surfactants during the pigment synthesis is also optimized. Once dried and ground to a precise size, pigments are mixed with a commercial binder and applied to a metallic substrate to study their properties. Thermal stability to high temperature is studied with different tests. The results showed that laminar structure was preferred to intercalate larger amounts of metallic salt into the clay structure, and no significant differences were found when using silane or surfactant modifiers. Although the highest absorptivity value was 85% after 24 h at 600 degrees C, samples presented very good adherence to the metallic substrate. Addition of a small quantity of commercial black pigment to the paint composition could improve the absorptivity and maintain the excellent adhesion shown. Furthermore, montmorillonite clay, modified with a surfactant before adding metallic salt, and without silane, resulted in a black pigment in a powder form. This pillared clay could be used in future paint formulations. (C) 2017 Elsevier Ltd. All rights reserved.