1,721,096 research outputs found
Preface
No full textThe idea of this book originates from the need to have a simple yet wide and
reliable source of information on fundamental and applicative aspects related
to SGP, built on the experience gained so far by researchers and R&D-driven companies.
The book covers the many facets of this complex subject, making also an
attempt to standardising nomenclature, process classification, and relevant figures
of merit
Technologies for Desalination of Brackish and Sea Water
No full textThis chapter thoroughly examines various brackish and seawater desalination technologies, including thermal- and membrane-based methods. Conventional thermal methods account for roughly one-third of the world’s installed desalination capacity. This work provides an in-depth analysis of traditional thermal techniques such as Multi-Stage Flash (MSF) distillation, Multi-Effect Distillation (MED), and Mechanical Vapour Compression (MVC), along with innovative methods like solar-driven evaporative desalination processes. The analysis of these methods includes their principles, and performance metrics. Membrane Distillation (MD) offers an innovative solution, positioned between thermal and membrane-based technologies. This advanced technology is comprehensively presented and discussed in detail. The discussion extends to membrane-based desalination technologies, particularly pressure-driven processes such as Reverse Osmosis (RO), which is currently the most widely used method. The chapter further explores the operational principles of RO, its advantages, limitations, and technological advancements. Additionally, emerging membrane technologies such as Nanofiltration (NF), Forward Osmosis (FO), and Osmotically-Assisted Reverse Osmosis (OARO) are examined, highlighting their potential and current applications. Among electrically driven membrane processes, Electrodialysis (ED) has received special attention. This chapter provides insights into its operational mechanisms, efficiency, and applications, along with a discussion on Electrodeionization (EDI) and Electrodialysis with Bipolar Membranes (EDBM). For each category of desalination technology, water desalination plants currently operating worldwide are classified based on their production capacity, the technology used, and geographical distribution. This classification offers a practical overview of the global deployment of desalination technologies and their regional adaptations. The chapter also delves into hybrid systems in water desalination, which aim to combine and integrate the advantages of various desalination technologies to develop more efficient and sustainable systems. Several examples of such integrated systems, including renewable energy-driven desalination systems and integrated membrane technology desalination systems, are described and briefly discussed. The potential for coupled hybrid systems to address specific challenges in desalination is also explored. Future research in water desalination is expected to focus on these hybrid approaches, optimizing the integration of different technologies to enhance water recovery, energetic performance and sustainability. This chapter serves as a comprehensive resource for understanding current desalination technologies, their global application, and future trends in the field
Simulation-based design of a bipolar membranes electrodialysis unit for chemicals production from brines
No full textNowadays environmental concerns are modifying the production and consumption patterns used so far. An
important objective to improve our society is the use of sustainable processes that can reduce industrial waste
streams. Bipolar membranes electrodialysis (EDBM) is an emerging environmentally friendly process that
could be easily integrated into a circular economy approach to valorize waste brines. It is an electro-membrane
process that allows the production of chemicals using only water, electrical energy and a salty solution. When
electric current is applied to the electrodes of the EDBM stack, water dissociation takes place in the bipolar
membranes. Therefore, the ions from water are combined with those coming from the salt generating acid and
base. The increasing interest in the EDBM process requires appropriate design procedures. This study proposed
a simulation-based design of a EDBM unit for the production of hydrochloric acid and sodium hydroxide from
sodium chloride solution. The design was performed in terms of configuration and operational conditions. A
model, realized by Culcasi et al. [1], was used to describe the EDBM process’s behaviour. This model was
validated with experimental data so that a high quality design could be achieved. This procedure was used to
design a EDBM unit that will be part of the demo-plant of the Horizon 2020 Water-Mining project
Energy analysis of electrodialisys with bipolar membranes for chemicals production
Full text linkIntroduction. Electrodialysis with bipolar membranes (EDBM) is an emerging electro-membrane process
suitable for the simultaneous production of acid and base streams. Its environmentally friendly nature
together with the wide application fields of its products have recently increased the attention toward this
process [1].
EDBM can be employed for in situ production of chemicals, reducing transportation, handling and storage
costs and burdens, but also integrated with other technologies into circular approaches for the valorization
of residual streams, recovering high value materials and minimizing discharged volumes. Notwithstanding
these promising aspects, reduced performances were registered in some cases [2], especially for high
chemicals concentration targets. This suggests that EDBM should be employed preferably when diluted acid
and base streams are needed (below 5 wt.% in the case of sodium hydroxide and hydrochloric acid) and that
more effort should be dedicated in selecting the process conditions and plant configurations minimizing
energy consumption.
The aim of the present work is to study EDBM behavior in different process configurations (both continuous
and discontinuous) and to energetically characterize it to choose the most appropriate configuration
depending on products requirements and process capacity.
Methodology. A fully validated distributed parameters multi-scale model [3] was employed to simulate
three different process configurations, namely open-loop, closed-loop and feed & bleed. The model is
capable of predicting also non-ideal phenomena, such as concentration polarization, undesired fluxes (i.e.,
osmotic, diffusive and electroosmotic) and current leakages via manifolds. The configurations were studied
under different conditions (i.e., process capacity and target concentrations) and compared in terms of the
energy use efficiency fixing final products target and salt conversions.
Results and discussion. Results demonstrated that the open-loop configuration shows the best performances
at low target concentrations and process capacity, due to the absence of back-mixing effect between outlet
products and inlet streams, which cause irreversible dissipative phenomena. However, at high target
concentrations, elevated current densities or reduced channel velocity in the stack should be adopted, which,
in turn, lead to a significant performance reduction. Instead, feed & bleed turns to be the most competitive
at high target concentration and medium-high capacity, due to the increase in current utilization, as the
current density rises. Finally, the closed-loop configuration results the most flexible in terms of process
capacity, but shows lower performance with respect to the other two configurations. This can be related to
the high impact of chemical energy losses due to mixing phenomena in the solutions tank.
This analysis can guide the selection of the most appropriate process configuration to reduce energy
consumption, also highlighting the most relevant features for EDBM process coupling when variable sources
of energy have to be adopted, such as renewable energies or smart grid integration.
Acknowledgments
This project has received funding from the European Union’s Horizon 2020 research and innovation program under Grant
Agreement no. 869474 (WATER-MINING-next generation water-smart management systems: large scale
demonstrations for a circular economy and society). https://watermining.eu/.
References
[1] Huang, C., & Xu, T., Environmental Sicence and Technology 2006, 40(17), 5233-5243.
[2] Herrero-Gonzalez, M. et al., Separation and Purification Technology 2020, 242.
[3] Culcasi, A. et al., Chemical Engineering Journal 2022, 437, 135317
Effect of Design Features and Operating Conditions on the Performance of a Bipolar Membrane-Based Acid/Base Flow Battery
Full text linkIn the context of renewable energy sources, storage systems have been proposed as a solution to the issues related to fluctuations in the production and consumption of electric power. The EU funded BAoBaB project is aimed at developing the Acid/Base Flow battery (AB-FB), an environment-friendly, cost-competitive, grid-scale battery storage system based on the cyclic coupling of Bipolar Membrane ElectroDialysis (BMED) and its reverse, the Bipolar Membrane Reverse ElectroDialysis (BMRED) (Pärnamäe et al., 2020). Bipolar membranes promote catalytically water dissociation, thus allowing the storage of electric power in the form of acidic and alkaline solutions (pH gradient), obtained from their corresponding salt (charging mode - BMED), which are then recombined to provide electrical power (discharging mode - BMRED). The membranes are key elements for the process performance; however, the energy conversion efficiency is also affected by the operating parameters of the process and the design features of the stack. In this work, we performed a sensitivity analysis by a mathematical multi-scale model previously developed (Culcasi et al., 2020a). The performance of AB-FB systems was predicted, focusing on the Round Trip Efficiency. Results showed that proper design features made the effect of parasitic currents negligible. Moreover, proper operating conditions maximized the RTE up to 66%
Feasibility of Producing Electricity, Hydrogen, and Chlorine via Reverse Electrodialysis
No full textThis is a short instruction file containing data sets for the publication "Feasibility of Producing Electricity, Hydrogen, and Chlorine via Reverse Electrodialysis" by Ameya Ranade, Kaustub Singh, Alessandro Tamburini, Giorgio Micale and David A. Vermaas.
1. The contents are subdivided into the processed data of figures in the manuscript and the SI.
2. The MATLAB script (one_d_model) contains the code used to calculate the various profiles in the manuscript
Bipolar membrane reverse electrodialysis for the sustainable recovery of energy from pH gradients of industrial wastewater: Performance prediction by a validated process model
Full text linkThe theoretical energy density extractable from acidic and alkaline solutions is higher than 20 kWh m-3 of single solution when mixing 1 M concentrated streams. Therefore, acidic and alkaline industrial wastewater have a huge potential for the recovery of energy. To this purpose, bipolar membrane reverse electrodialysis (BMRED) is an interesting, yet poorly studied technology for the conversion of the mixing entropy of solutions at different pH into electricity. Although it shows promising performance, only few works have been presented in the literature so far, and no comprehensive models have been developed yet. This work presents a mathematical multi-scale model based on a semi-empirical approach. The model was validated against experimental data and was applied over a variety of operating conditions, showing that it may represent an effective tool for the prediction of the BMRED performance. A sensitivity analysis was performed in two different scenarios, i.e. (i) a reference case and (ii) an improved case with high-performance membrane properties. A Net Power Density of ~15 W m-2 was predicted in the reference scenario with 1 M HCl and NaOH solutions, but it increased significantly by simulating high-performance membranes. A simulated scheme for an industrial application yielded an energy density of ~50 kWh m-3 (of acid solution) with an energy efficiency of ~80-90% in the improved scenario
Membrane deformation and its impact on the flow-field in Reverse Osmosis permeate channels
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