Search results for "dialysi"

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

INNOVATIVE APPLICATIONS OF EXERGY ANALYSIS AND THERMOECONOMICS IN CHEMICAL, THERMAL AND COOLING ENERGY CONVERSION SYSTEMS

Since 70s, the world has been becoming more and more concerned about energy and environmental issues. The need of meeting the current energy demand by guaranteeing the ability of future generation to satisfy theirs have been pushing research not only to exploit alternative energy sources such as renewable energies, but also to improve the efficiency of energy conversion systems. To this regard, developing systems that use efficiently energy is of paramount importance especially in those countries which rely on non-renewable energy sources such as oil, natural gas, and coal. In fact, the reduction of energy consumption will lead not only to the saving of unrestorable and limited energy resou…

Exergy analysis and thermoeconomic cost accounting of a Combined Heat and Power steam cycle integrated with a Multi Effect Distillation-Thermal Vapou…

2017

Abstract In this paper an exergy analysis and thermoeconomic cost accounting of a Combined Heat and Power steam cycle integrated with Multi Effect Distillation-Thermal Vapour Compression plant is performed; the goal of the study is to show how these methodologies provide a rational criterion to allocate production costs on electricity and freshwater in such a dual purpose system. After a brief overview on the methodology and a description of reference plant, exergy analysis is carried out to calculate exergy flows and exergy efficiencies at component level. A detailed description of the adopted thermoeconomic model is given. In a first scenario, cost accounting is performed assuming that th…

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…

Exergy analysis of reverse electrodialysis

2018

Abstract Reverse electrodialysis in closed loop configurations is a promising membrane technology in the energy conversion and storage fields. One of the main advantages of closed-loop reverse electrodialysis is the possibility of using a wide range of operating concentrations, flow rates and different salts for generating the salinity gradient. In this work, an original exergy analysis of the reverse electrodialysis process was carried out in order to investigate reverse electrodialysis performance in terms of energetic and exergetic efficiency parameters in a wide range of operating conditions. A mono-dimensional model of the reverse electrodialysis process was developed, in which all sou…

The efficacy of single suture for exit site wound closure and stabilization of hemodialysis central tunneled catheter

2021

Introduction: The majority of the end-stage renal disease patients begin hemodialysis with the central tunneled catheter as a permanent or bridge vascular access. The procedure of central tunneled catheter insertion can be complicated by exit site bleeding, prolonged tunnel healing, and infection. The study aimed at evaluating whether the catheter exit site wound closing with a single-suture method is equally effective as the double suture method, which is most frequently applied. The assumption was that the single-suture method, which is less traumatizing for the skin, could offer an advantage for the patients with “paper” skin, that is, elderly, after long-term immunosuppressive treatment…

Influence of bundle porosity on shell-side hydrodynamics and mass transfer in regular fiber arrays: A computational study

2023

CFD predictions of the effects of a fiber bundle porosity on shell-side hydrodynamics and mass transfer under conditions of steady laminar flow were obtained. Fluid was assumed to flow around regular hexag-onal or square arrays of cylindrical fibers of different pitch to diameter ratios, yielding bundle porosities ranging from the theoretical minimum up to similar to 1. A large number of axial, transverse and mixed flow combinations were simulated by letting the axial and transverse flow Reynolds numbers and the trans-verse flow attack angle vary. Both fully developed and developing conditions (entrance effects) were con-sidered. The continuity and momentum equations, along with a transport…