Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation

An electrochemical reactor was developed to recover zinc from the spent pickling solutions coming from the hot dip galvanizing industry. These solutions mainly contain ZnCl2 and FeCl2 in aqueous HCl media. The effect of the applied potential on the figures of merit (fractional conversion, current efficiency, space-time yield and specific energy consumption) of the electrochemical reactor was analysed. Voltammetric experiments were performed previously in order to select the optimum conditions to be applied in the electrolysis experiments. From the I-V curves it was inferred that bulk zinc deposition started from potential values more cathodic than -0.99 V. The hydrogen evolution reaction (HER) appeared from -0.45 V and masked the zinc cathodic peak C1, related to bulk zinc deposition, at high HCl concentrations. The presence of HCl inhibited iron deposition in synthetic samples. The additives present in the real baths, which diminish the massive hydrogen generation, allowed the observation of peak C1. The potential values to be applied in the electrolysis experiments were chosen from the voltammetric experiments and ranged between -1 V and -1.75 V. In the absence of iron in solution, as the electrode potential was shifted towards more negative values, the space-time yield of zinc and its fractional conversion increased because of the increase in the electrode roughness and the hydrogen turbulence-promoting action. Simultaneously, the specific energy consumption decreased initially due to the increase in the zinc conversion rate but decreased for the most cathodic potential value due to HER. The presence of iron in synthetic solutions led to a decrease in current efficiency associated with the reverse redox Fe 2+/Fe3+ system and to the enhancement of the HER, which also induced increments in the local pH and the subsequent zinc redissolution for the most cathodic potential values. On the contrary, the additives present in the real spent pickling baths avoided the adverse effects of iron, and zinc electrodeposition was possible even at high cathodic potential values. In fact, a potential value of -1.75 V was selected as the optimum since the conversion, the current efficiency and the space time yield obtained in the real baths were relatively high.Authors want to express their gratitude to the Universidad Politecnica de Valencia for the economical support in the project reference PAID-06-08, and to the Generalitat Valenciana for the financing of the project reference GV/2010/029.Carrillo Abad, J.; García Gabaldón, M.; Ortega Navarro, EM.; Pérez-Herranz, V. (2011). Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation. Separation and Purification Technology. 81(2):200-207. https://doi.org/10.1016/j.seppur.2011.07.029S20020781

Analysis, Evaluation and Simulation of Railway Diesel-Electric and Hybrid Units as Distributed Energy Resources

The objective of this paper involves the analysis, identification and evaluation of different possibilities offered by technology for the improvement and the management of the use of energy and hybridization in railways: On board generation, demand response and energy storage, both in traction and auxiliary loads, considering the aggregation of resources and its stochastic nature. The paper takes into account the importance of efficient use of energy in railways, both currently (trains in service, prototypes) and in the future, considering the trends driven by energy policy scenarios (2030–2050) that will affect service and operation of units during their lifetime. A new activity has been considered that will be relevant in the future in the framework of a new electricity supply paradigm: Smart-Grids. According to this paradigm, the interaction of the Electric Power System and the Railway Supply System (somehow embedded in the Power System) will bring new opportunities for the collaboration of these two systems to perform, in a wise economic fashion, a better and more reliable operation of the complete energy system. The paper is focused on a mixed profile with low-medium traffic (passenger and freight): The first part of the route is electrified (3 kV DC catenary) whereas the second part is not electrified. Results justify that complex policies and objectives bring an opportunity to make cost-effective the hybridization of railway units, especially in low/medium traffic lines, which improves their social and economic sustainability.Authors are very grateful to the information, data and technical discussions provided by Patentes Talgo S.A. (Spain). This work was supported by the Ministerio de Ciencia, Innovación y Universidades (Spanish Government) under research project ENE-2016-78509-C3-2-P; Ministerio de Educación (Spanish Government) under grant FPU17/02753 and especially EU FEDER funds. This work was supported by the Ministerio de Ciencia, Innovación y Universidades, Spanish Government) under research project ENE-2016-78509-C3-2-P; Ministerio de Educación through grant FPU17/02753 and EU FEDER funds. Authors have also received funds from these grants for covering the costs to publish in open access

Estudio electroquímico y recuperación del estaño y del paladio mediante un reactor electroquímico de compartimentos separados

La Tesis Doctoral "Estudio electroquímico y recuperación del estaño y del paladio mediante un reactor electroquímico de compartimentos separados" se centra en el estudio de la posibilidad de recuperación del estaño y del paladio procedentes de las disoluciones de activado de las industrias de metalizado de plásticos mediante la utilización de un reactor electroquímico de compartimentos separados mediante un diafragma cerámico. Con la recuperación de estos metales se pretende por una parte minimizar la contaminación producida en la etapa de activado, y por otra parte conseguir un ahorro de materias primas puesto que una vez recuperados los metales podrían ser utilizados de nuevo en el proceso de activado. Para que el proceso de activado se desarrolle de manera óptima debe de existir una relación determinada entre el Sn(II) y el Sn(IV), por tanto es necesario conocer en todo momento la concentración de ambas especies. Así en la primera parte de la Tesis se ha puesto a punto una nueva técnica polarográfica capaz de determinar el contenido en Sn(II) y en Sn(IV) del baño de activado con el objeto de evitar su degradación. El estudio electroquímico de los baños de activado ha permitido seleccionar las condiciones idóneas de trabajo, potencial de electrodo e intensidad de corriente, para recuperar ambos metales sobre la superficie del cátodo de manera conjunta o separada. Por otra parte, se ha realizado un estudio de diferentes separadores cerámicos situados entre los compartimentos del reactor electroquímico con el objetivo de seleccionar aquel cuya resistencia a la migración iónica sea la mínima pero que a la vez su resistencia a la convección y a la difusión de especies sea la máxima. Mediante el separador seleccionado se pretende evitar el paso del Sn(II) hacia el compartimiento anódico, donde se oxidaría a Sn(IV) produciendo un menor rendimiento del proceso. Por último, con los estudios previos se ha realizado la puesta a punto del reactor electroquímico donde se ha evaluado el efecto de la intensidad y el potencial de trabajo sobre los depósitos metálicos formados y sobre las principales "figuras de mérito" del reactor, como son la conversión de reactivo, la productividad específica, el rendimiento eléctrico del proceso y la energía específica consumida.Al Ministerio de Ciencia y Tecnología por su ayuda a través del financiamiento del Proyecto PPQ2000-0689-C02-01 en el cual se enmarca mi Tesis Doctoral. Al Ministerio de Educación y Cultura por la concesión de una beca predoctoral de Formación de Profesorado Universitario para el desarrollo de la Tesis.García Gabaldón, M. (2005). Estudio electroquímico y recuperación del estaño y del paladio mediante un reactor electroquímico de compartimentos separados [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/135281TESI

Energy efficiency in railways: energy storage and electric generation in diesel electric locomotives. Póster

Diesel-electric traction is a well known and established technology for railways operators,but this alternative has a considerable uncerainty for the future because electric traction has a considerable superiority. Besides,diesel-electric engines was teenergy when resistive braking isused This non-regenerative braking decreases the overall efficiency by lO-20%.With these premises it is important to develop new strategies to increase the energy efficiency of diesel-electric haulag. To reach a better efficiency,a locomotive with energy storage(battery,super-capacitors)is theoretically proposed.Besides,the possibility of using alower thermal engine(from other diesel locomotives out of use)with energy storage devices is considered too.This solution reduces diesel consumption and CO2 emissions while being economically viable.It supposes an efficient energy management because the diesel-electric locomotive could acts as a dispersed mobile generation(DMG)unit when working under electric overhead lines,and it can be used as a distributed resource for this specific electric power system

Assessment and simulation of the responsive demand potential in end-user facilities: application to a university customer

Many problems have appeared with the practical implementation of restructured electrical business in the U.S.and European Union such as lack of generation,network constraints,etc. A good example of these problems is the scarce participation of the demand in the electricity markets—energy,reserve,and other ancillary services—problems that could be solved through new de-mand responsive programs,aimed to replace the traditional demand side management programs in to voluntary demand partici-pation programs.A methodology for the generation of demand side bids and ofers in large customer facilities and a real application to a university customer is presented in this paper.The methodology is based on the knowledge of the physical processes involved in the electricity consumption and on the flexibility of there quired supply.The result of the methodology proposed is a set of demand packages that can be used to participate in different electricity markets,whose possibilities- in the market arena — will be explored in a consequent paper.This work was supported by the Ministerio de Ciencia y Tecnología of Spain through Research Project DPI2001-2779-C02-01

Study of the zinc recovery from spent pickling baths by means of an electrochemical membrane reactor using a cation-exchange membrane under galvanostatic control

The performance of a cation-exchange membrane (CEM) used for recovering zinc from real spent pickling baths is studied in this work. These spent baths contain high amounts of ZnCl2 and FeCl2 in aqueous HCl media. The results obtained with this membrane are compared with those obtained with an anion-exchange membrane (AEM) treating the same effluent. The effect of the presence or absence of initial zinc in the cathodic compartment is also studied. The absence of initial zinc in the cathodic compartment in the CEM experiments permits iron codeposition. Furthermore, the results obtained with the CEM are worse than those obtained with the AEM for all the figures of merit. This fact shows the need of filling the cathodic compartment with a synthetic zinc solution. The presence of zinc in the cathodic compartment from the beginning of the electrolysis not only inhibits iron codeposition but also favors zinc deposition as the hydrogen evolution reaction becomes a secondary reaction, improving by this way the results of all the figures of merit of the reactor with the CEM. A deep study about the effect of the applied current and the concentration of the synthetic zinc solution placed in the cathodic compartment permits to reach the equilibrium between the zinc transferred through the membrane and that deposited on the cathode. Therefore, the synthetic cathodic zinc is not consumed at any time. Moreover, under this circumstances iron codeposition is also avoided.The authors want to express their gratitude to the Generalitat Valenciana for a postgraduate Grant (GV/2010/029) and to the Ministerio de Economia y Competitividad for financing the project number CTQ2012-37450-C02-01/PPQ.Carrillo Abad, J.; García Gabaldón, M.; Pérez Herranz, V. (2014). Study of the zinc recovery from spent pickling baths by means of an electrochemical membrane reactor using a cation-exchange membrane under galvanostatic control. Separation and Purification Technology. 132:479-486. https://doi.org/10.1016/j.seppur.2014.05.052S47948613

pH effect on zinc recovery from the spent pickling baths of hot dip galvanizing industries

[EN] In this work, the pH effect on the zinc electrowinning present in the spent pickling baths (SPBs) is analysed with the aim of decreasing the energetic cost of the process. Specifically, the effect of increasing the initial pH with and without its control during the whole electrolysis experiment is studied on synthetic solutions with concentration values similar to those present in the spent pickling baths. Finally, real SPBs are treated under pH control and the results obtained are also compared with those acquired with the direct electrolysis of these SPBs in a membrane reactor. The modification of the initial pH on synthetic solutions shows an increase in zinc deposition rate as the initial pH is risen. However, the zinc redissolution phenomenon is present during the whole experiment. On the other hand, when the pH is controlled, the results obtained are much better as zinc redissolution is prevented and the hydrogen evolution reaction rate is decreased. Comparing the behaviour between the reactor under pH control and that in the presence of an anion exchange membrane, reflects zinc conversion values slightly higher for the membrane reactor due to the zinc precipitation occurring in the reactor under pH control, which is higher as the pH rises. However, the specific energy consumption is considerably higher in the membrane reactor mainly due to the ohmic drop introduced by the membrane. (C) 2016 Elsevier B.V. All rights reserved.Carrillo Abad, J.; García Gabaldón, M.; Pérez-Herranz, V. (2017). pH effect on zinc recovery from the spent pickling baths of hot dip galvanizing industries. Separation and Purification Technology. 177:21-28. doi:10.1016/j.seppur.2016.12.034S212817

Los privilegios marítimos sobre el buque

Se hace un análisis histórico en el que se estudia el buque como garantía de créditos marítimos desde la antigüedad hasta el derecho marítimo medieval, la tipificación de los créditos marítimos privilegiados en la e. Moderna y la génesis y evolución de los "maritime liens" en el derecho norteamericano. Se analizan las fuentes del derecho marítimo para ahondar en el concepto y naturaleza jurídicos y la distinción de figuras afines. Se estudia la caracterización de los privilegios marítimos, la reper secutoriedad, la preferencia y la precariedad. Se analizan, por último, los principios ordenadores de las normas de conflicto sobre los problemas marítimos, la ley del pabellón y los conflictos móviles y el conflicto móvil en el derecho español

Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation

The performance of a one- and two-compartment electrochemical reactor under galvanostatic control for zinc recovery present in the spent pickling solutions is studied in this paper. These solutions, which mainly contain ZnCl 2 and FeCl 2 in aqueous HCl media, come from the hot dip galvanizing industry. The effect of the anion-exchange membrane (AEM) on the figures of merit of the electrochemical reactor is analyzed. In the absence of iron in solution, as the current value was shifted towards more negative values, the zinc fractional conversion increased because of the increase in the zinc reduction rate. However, the increase in current values made current efficiency decrease due to the hydrogen-reduction side reaction, which caused an increment in the specific energy consumption. The presence of iron in synthetic solutions led to a decrease in current efficiency associated with the reverse redox Fe 2+/Fe 3+ system and to the enhancement of the HER, which also induced increments in the local pH and the subsequent zinc redissolution. These adverse effects related to the presence of iron could be minimized by the interposition of an AEM. In this case, the zinc redissolution was eliminated which enabled zinc conversion values close to 100% together with higher current efficiencies as the consumption of current by the system Fe 2+/Fe 3+ was diminished. © 2012 Elsevier B.V. All rights reserved.Authors want to express their gratitude to the Universidad Politecnica de Valencia for the economic support in the Project Reference PAID-06-08, and to the Generalitat Valenciana for the financing of the Project Reference GV/2010/029.Carrillo Abad, J.; García Gabaldón, M.; Ortega Navarro, EM.; Pérez-Herranz, V. (2012). Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation. Separation and Purification Technology. 98:366-374. https://doi.org/10.1016/j.seppur.2012.08.006S3663749