Search results for "DIALYSIS"

Evaluation of the Economic and Environmental Performance of Low-Temperature Heat to Power Conversion using a Reverse Electrodialysis – Multi-Effect D…

2019

In the examined heat engine, reverse electrodialysis (RED) is used to generate electricity from the salinity difference between two artificial solutions. The salinity gradient is restored through a multi-effect distillation system (MED) powered by low-temperature waste heat at 100 °C. The current work presents the first comprehensive economic and environmental analysis of this advanced concept, when varying the number of MED effects, the system sizing, the salt of the solutions, and other key parameters. The levelized cost of electricity (LCOE) has been calculated, showing that competitive solutions can be reached only when the system is at least medium to large scale. The lowest LCOE, at a…

CFD simulation of channels for direct and reverse electrodialysis

2012

Flows within very thin channels, typically filled with spacers, can be often encountered in many processes such as electrodialysis (ED) and reverse electrodialysis (RED). Although the ED and the RED processes have been studied for a long time, the optimization of the fluid dynamics within the channels is still an open problem. In the present work, realized within the EU-FP7 funded REAPower project, computational fluid dynamics simulations were carried out in order to predict the fluid flow field inside a single ED/RED channel. Some different configurations were tested which includes: an empty channel, a channel provided with a spacer, and a channel filled with a purposely manufactured fiber…

Reverse electrodialysis

2016

Abstract Reverse electrodialysis (RED) technology has grown significantly in the last decade, gaining a fast increase in its technology readiness level and presenting some interesting examples of RED pilot systems operating under very different real environments. In this chapter, an overview of technological developments and piloting examples are reported. In particular, a short introduction is given on the historical trend of RED technology growth, followed by a careful analysis of which feed solutions can be adopted and how these can affect the process performance, potentials, and applications. Most prominent fluid dynamics aspects for the RED process are presented, highlighting how these…

Analysis and simulation of scale-up potentials in reverse electrodialysis

2015

The Reverse Electrodialysis (RED) process has been widely accepted as a viable and promising technology to produce electric energy from salinity difference (salinity gradient power - e.g. using river water/seawater, or seawater and concentrated brines). Recent R&D efforts demonstrated how an appropriate design of the RED unit and a suitable selection of process conditions may crucially enhance the process performance. With this regard, a process simulator was developed and validated with experimental data collected on a lab-scale unit, providing a new modelling tool for process optimisation. In this work, performed within the REAPower project (www.reapower.eu), a process simulator previousl…

A simulation tool for analysis and design of reverse electrodialysis using concentrated brines

2015

Abstract Reverse electrodialysis (SGP-RE or RED) represents a viable technology for the conversion of the salinity gradient power into electric power. A comprehensive model is proposed for the RED process using sea or brackish water and concentrated brine as feed solutions. The goals were (i) reliably describing the physical phenomena involved in the process and (ii) providing information for optimal equipment design. For such purposes, the model has been developed at two different scales of description: a lower scale for the repeating unit of the system (cell pair), and a higher scale for the entire equipment (stack). The model was implemented in a process simulator, validated against orig…

Coupling CFD with a one-dimensional model to predict the performance of reverse electrodialysis stacks

2017

Abstract Different computer-based simulation models, able to predict the performance of Reverse ElectroDialysis (RED) systems, are currently used to investigate the potentials of alternative designs, to orient experimental activities and to design/optimize prototypes. The simulation approach described here combines a one-dimensional modelling of a RED stack with a fully three-dimensional finite volume modelling of the electrolyte channels, either planar or equipped with different spacers or profiled membranes. An advanced three-dimensional code was used to provide correlations for the friction coefficient (based on 3-D solutions of the continuity and Navier-Stokes equations) and the Sherwoo…

Reverse electrodialysis performed at pilot plant scale: Evaluation of redox processes and simultaneous generation of electric energy and treatment of…

2017

Abstract This paper describes the experimental campaign carried out with a reverse electrodialysis (RED) demonstration plant (Marsala, Italy) with the main aims of: (i) evaluating the effect of various operating parameters, including the redox processes, on the system performances; (ii) using the plant for the simultaneous generation of electric energy and treatment of wastewater. The prototype (44 × 44 cm2, 500 cell pairs) was tested using both real (brackish water and brine) and artificial solutions. Tests with two different electrode rinse solutions (with or without iron redox couples) were performed. In agreement with the data obtained in the laboratory, the presence of iron ions contri…

SP619The effect of etelcalcetide in hemodialysis patients with secondary hyperparathyroidism in daily clinical practice. A prospective multicenter st…

2019

Reverse electrodialysis heat engine with multi-effect distillation: Exergy analysis and perspectives

2019

Abstract The increasing worldwide energy demand is rising the interest on alternative power production technologies based on renewable and emission-free energy sources. In this regard, the closed-loop reverse electrodialysis heat engine is a promising technology with the potential to convert low-grade heat into electric power. The reverse electrodialysis technology has been under investigation in the last years to explore the real potentials for energy generation from natural and artificial solutions, and recent works have been addressing also the potential of its coupling with regeneration strategies, looking at medium and large energy supply purposes. In this work, for the first time, a c…

Performance Analysis of a RED-MED Salinity Gradient Heat Engine

2018

A performance analysis of a salinity gradient heat engine (SGP-HE) is presented for the conversion of low temperature heat into power via a closed-loop Reverse Electrodialysis (RED) coupled with Multi-Effect Distillation (MED). Mathematical models for the RED and MED systems have been purposely developed in order to investigate the performance of both processes and have been then coupled to analyze the efficiency of the overall integrated system. The influence of the main operating conditions (i.e., solutions concentration and velocity) has been quantified, looking at the power density and conversion efficiency of the RED unit, MED Specific Thermal Consumption (STC) and at the overall syste…