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[en] Use of unconventional water resources such as desalination is becoming inevitable sources to alleviate water scarcity in the world. Desalination of brackish water is one of the non conventional water resources that the Tunisian government developed in order to enhance the quality of water distributed in the south. Despite the many benefits desalination technology has to offer a list of potential environmental like the emissions of air pollutant, the energy demand, land use but the main impact of desalination plant is caused by the discharge of an effluent of very high salinity. The constant discharge of reject streams with high salinity and temperature can be fatal for marine life. The purpose of this study is to evaluate the chemical composition of reject brine from Gabes desalination plant and Jerba desalination plant. Both desalination plants are planted to securing the fresh water supply for consumer consumption to the respectively government Gabes and Jerba when the level of salinity is exceeded 3g /l. The average capacity of these plants varied between 25000m3/d and 30 000m3/d. Water samples were collected from several locations at reject site of both desalination plant Jerba and Gabes. All samples have been analysed for major, nutritive and minor constituents The analyses reveal a difference between the compositions of brine of the both stations, The comparison between quality of the effluent discharged and Tunisian norms of reject in hydraulic areas (NT 106 002) showed that the concentration of calcium, chlorides sodium sulphates are higher than the allowable limits the norms.
[en] This paper presents an update of a dynamic library of reverse osmosis plants (ROSIM). This library has been developed in order to be used for optimization, simulation, controller testing or fault detection strategies and a simple fault tolerant control is tested. ROSIM is based in a set of components representing the different units of a typical reverse osmosis plant (as sand filters, cartridge filters, exchanger energy recoveries, pumps, membranes, storage tanks, control systems, valves, etc.). Different types of fouling (calcium carbonate, iron hydroxide, biofouling) have been added and the mathematical model of the reverse osmosis membranes, proposed in the original library, has been improved.
[en] In the research the main desalination processes of sea and brackish water are analyzed and discussed. The processes can be separated into the categories of Thermal and Membrane Processes. The thermal processes can be further divided between those in which heat is supplied to the water, causing its evaporation (single-step evaporation processes, Multi flash processes and multiple effects processes of evaporation), and those, less frequently used, where the heat is instead subtracted, causing a phenomenon of crystallization. The membrane processes, on the other side, are based on the passage of salt or brackish water through synthetic semi-permeable membranes. They can be subdivided between those employing reverse osmosis processes, where the selective solvent passage through the membranes is guaranteed by high pressure differences and those based on electrodialysis.
[it]Nella ricerca vengono analizzati e discussi i principali processi di dissalazione delle acque marine e salmastre, che possono essere distinti nelle due categorie di Processi Termici e Processi a Membrana. I processi termici vengono quindi distinti tra quelli in cui viene fornito calore all'acqua, determinandone l'evaporazione (processi di evaporazione monostadio, processi multiflash e processi di evaporazione ad effetti multipli), e quelli, molto meno utilizzati, in cui il calore e invece sottratto, determinando un fenomeno di cristallizzazione. I processi a membrana, invece, prevedono il passaggio dell'acqua salata o salmastra attraverso membrane sintetiche semi-permeabili. La principale distinzione operabile tra i processi a membrana riguarda i processi ad osmosi inversa, in cui si impongono elevate differenze di pressione per consentire il passaggio attraverso le membrane del solo solvente (inibendo il passaggio degli ioni), e quelli ad elettrodialisi.
[en] The subject of my lecture is the use of nuclear energy for sea water desalination. During this study course this is the only lecture we will have on desalination and therefore we have many points to cover. I propose to cover these points in the following order: (1) Determining the feasibility, of nuclear desalination (2) Nuclear desalination and plant cycles (3) Additional nuclear desalination plant considerations and recent desalination developments. In several cases, whore there is only time for a summary, there is a more complete treatment in the Appendices.
[en] In this article we offer various opportunities of reproduction of sea water for power plants on desalination installations described by high thermal perfection a variants of such schemes. Advantages of modes of installations are shown from the point of view of hydrodynamics and heat exchange. The parameters determining their perfection and profitability are presented. (author)
[en] The focus of this paper is on examination of hybrid systems and hybrid technology in order to take full advantage of both thermal and electrical energy as well as membrane processes. This article is based and updated from Awerbuch hybrid chapter contribution to book by M. Wilf 'The Guidebook to Membrane Desalination Technology'. Two comprehensive studies were carried out on hybrid desalination systems by Daniel Hoffman and Amnon Zfati and by Sherman May, and full review by Awerbuch
[en] Nuclear Desalination Demonstration Plant at Kalpakkam consists of both Multi Stage Flash Distillation (MSF) and Seawater Reverse Osmosis (SWRO) process to produce desalinated water. It supplies part of highly pure water from MSF to Madras Atomic Power Station for its boiler feed requirements and remaining water is blend with SWRO product water and sent to other common facilities located inside Kalpakkam campus. A critical techno-economic analysis is carried out to find out the suitability of second pass RO to sustain the availability of highly pure water in case of MSF plant shutdown. (author)
[en] Highlights: ► Porous media was used to simulate the pressure drop across desalination demister. ► Simulation results plausibly compared with experimental results. ► FC inlet Velocity distribution has no effect on the demister pressure drop. ► Demister inertial resistance affects pressure drop more than viscous resistance. - Abstract: This paper presents a numerical simulation of the water vapor flow in an MSF flash chamber along with the pressure drop across the demister. The demister is a simple porous blanket of metal wires mesh (usually made of stainless steel wires) which retains liquid droplets entrained by the vapor momentum to enhance the quality of the product water. Two main areas of concern in wire mesh mist eliminators are; (i) the pressure drop and (ii) the mist removal efficiency. The present simulation focuses only on the pressure drop across the demister. The simulation is carried out considering a full scale flashing chamber of a typical operational MSF desalination plant and of a real industrial demister dimensions. The study simulates the demister as porous media flow. It takes into account the vapor velocity, the dimension of the demister, its porosity and wire thickness. The obtained pressure drop was found to be within a reasonable agreement with the published literature data and it follows a trend compatible with Ergun’s equation as well as the empirical correlation of Svendsen.
[en] The objective of this study is to assess the economics of SMART (System-integrated Modular Advanced Reactor) desalination plant in Korea through DEEP (Devaluation Economic Evaluation Program). SMART is mainly designed for the dual purpose of producing water and electricity with the total capacity of 100 MWe which 10 MWe is used for water production and the remains for the electric generation. SMART desalination plant using MED (Multi-Effect Distillation) process is in the stage of the commercial development and its cost information is also being accumulated. In this circumstances, the economic assessment of nuclear desalination by SMART and the effect of water(or electric) supply price to the regional economy is meaningful to the policy maker. This study is focused on the case study analysis about the economics of SMART desalination plant and the meanings of the case study result. This study is composed of two parts. One is prepared to survey the methodology regarding cost allocation between electricity and water in DEEP and the other is for the economic assessment of SMART. The cost allocation methods that have been proposed or used can be classified into two main groups, one is the cost prorating method and the other is the credit method. The cost of an product item in the dual-purpose plant can be determined differently depending on the costing methods adopted. When it comes to applying credit method adopted in this thesis, the production cost of water depends on what kind of the power cost will be chosen in calculating the power credit. This study also analyses the changes of nuclear desalination economics according to the changes of the important factors such as fossil fuel price. I wish that this study can afford to give an insight to the policy maker about SMART desalination plant. (authors)
[en] A fusion energy reactor is a potential source of electricity and heat for desalination of water. This note discusses the motivation, environmental issues, and a simplified schematic of such a desalination plant. A desalination facility producing ~ 100 million m3/day of potable water from seawater is well matched to a compact reactor operating in the hundred MW range.