Search results for "Electrodialysi"
showing 9 items of 159 documents
Pressure-Induced Deformation of Pillar-Type Profiled Membranes and Its Effects on Flow and Mass Transfer
2019
In electro-membrane processes, a pressure difference may arise between solutions flowing in alternate channels. This transmembrane pressure (TMP) causes a deformation of the membranes and of the fluid compartments. This, in turn, affects pressure losses and mass transfer rates with respect to undeformed conditions and may result in uneven flow rate and mass flux distributions. These phenomena were analyzed here for round pillar-type profiled membranes by integrated mechanical and fluid dynamics simulations. The analysis involved three steps: (1) A conservatively large value of TMP was imposed, and mechanical simulations were performed to identify the geometry with the minimum pillar density…
A hierarchical model for novel schemes of electrodialysis desalination
2019
Abstract A new hierarchical model for the electrodialysis (ED) process is presented. The model has been implemented into gPROMs Modelbuilder (PSE), allowing the development of a distributed-parameters simulation tool that combines the effectiveness of a semi-empirical modelling approach to the flexibility of a layered arrangement of modelling scales. Thanks to its structure, the tool makes possible the simulation of many different and complex layouts, requiring only membrane properties as input parameters (e.g. membrane resistance or salt and water permeability). The model has been validated against original experimental data obtained from a lab scale ED test rig. Simulation results concern…
Optimisation analysis of Reverse Electrodialysis systems for power production from concentrated brines
2016
Reverse Electrodialysis (RED) is rapidly growing as technology to produce electric energy by mixing saline solutions with different salinity. Recent developments have shown promising results on real site installations, demonstrating the feasibility of the RED process on the pilot scale. Therefore, further modelling efforts are now needed to optimise the technology, in order to enhance the performance. In this work, an optimisation study for the RED process is presented, taking into account saline waters and concentrated brine as feed streams. The model, which is developed within GAMS environment, predicts the optimal set of process variables that maximise the process yield, as well as the g…
ABATEMENT OF ACID ORANGE 7 IN WATER BY DIFFERENT ELECTROCHEMICAL APPROACHES
2014
Very large amounts of synthetic dyes are discharged in the environment from industrial effluents [1]. Due to their large-scale production and extensive application, synthetic dyes can cause considerable nonaesthetic pollution and are serious health-risk factors [2]. Dyes are commonly classified from their chromophore group. The majority of these compounds consumed at industrial scale are azo (–N=N–) derivatives that represent more than 50% of the all dyes used in textile industries, although antraquinone, indigoide, triphenylmethyl, xanthene, sulphur and phtalocyanine derivatives are frequently utilized [3]. Since dyes usually present high stability under sunlight and resistance to microbia…
Application of computational fluid dynamics technique in electrodialysis/reverse electrodialysis processes
2022
This Chapter treats the application of CFD technique in ED/RED processes. CFD simulations are able to predict flow and mass transfer in channels filled with spacers or membrane profiles, by providing dimensionless correlations useful for process models. At a larger scale, manifolds of the stack and inlet/ outlet zones of the channel can be simulated. Numerical models can include the computation of the electrical potential, thus characterizing the process performance. Direct numerical simulations can elucidate the complex phenomenology of overlimiting transport and of chaotic electrokinetic flows.
Electrodialysis with capacitive electrodes (CED): hierarchical process modelling for water desalination
2018
The present work describes the development of the first dynamic model for CED
ELECTROCHEMICAL TREATMENT OF WASTEWATERS DRIVEN BY REVERSE ELECTRODIALYSIS PROCESSES
2014
Wastewater treatment technology is undergoing a transformation due to more restrictive regulations governing the dischar ge and disposal of hazardous pollutants. Electrochemical based technologies are very promising methods for treating wastewaters containing organic and inorganic pollutants resistant to biological processes or toxic for microorganisms. These methods present numerous advantages including the utilisation of a green reagent such as the electron, very high removal of numerous recalcitrant pollutants, efficient disinfection, high flexibility and no necessity to transport or stock chemical oxidants or reducents. O n the other hand, a wide utilisation of such methods is likely to…
NH4HCO3–water solutions regeneration in RED closed loop applications
2017
Reverse Electrodialysis (RED) in closed loop arrangement (Reverse Electrodialysis Heat Engine - REDHE) is a promising technology to convert low-grade waste heat into electricity. RED is a membrane process exploiting the salinity gradient between a concentrated and a diluted solution to generate electrical current. Due to the transfer phenomena occurring in the RED unit, the two exiting solutions are partially mixed. Thermal regeneration processes can be used to restore the initial conditions of the two solutions, thus closing the loop. In this regard, ammonium hydrogen carbonate (NH4HCO3) salt solutions are suitable for such applications, being able to decompose at temperatures above 40-45 …
REVERSE ELECTRODIALYSIS FOR POWER PRODUCTION FROM OILFIELD WASTEWATERS
2022
Produced waters (PWs) are wastewaters generated by crude-oil extraction processes. They can present very different characteristics depending on the field location and production process. Dispersed oil, dissolved organics and solid particles are usually the main components. Moreover, PWs can contain a very high quantity of dissolved salts 1, with a total dissolved solid (TDS) concentration up to 300 g/L. Each barrel of extracted oil requires the simultaneous extraction of 3 barrels of produced water2 on average. PWs are often discharged into the sea, or sent in evaporation ponds thus leading to a dramatic environment impact3. Reinjection in the extraction well is currently the most common an…