Multi-effect distillation plants for small-scale seawater desalination: thermodynamic and economic improvement

Liponi, Angelica; Wieland, Christoph; Baccioli, Andrea

doi:10.1016/j.enconman.2019.112337

“…A time step of 6 min was used for the solution of the differential equations to have a more accurate estimation of the temperature profiles in the storage. For the MED plant, an Aspen Plus [15] model was developed as in [21], and the required thermal power and the produced amount of water were imported in the Matlab model as a look-up table.…”

Section: Methodsmentioning

confidence: 99%

“…A maximum salt concentration of 95% of the solubility was imposed to the brine at the exit of each effect as in [21]. In this way the recovery ratio (RR) was maximized as shown in [21]. This condition was achieved by imposing different mass flow rates of feed seawater in each effect.…”

Section: Of 16mentioning

confidence: 99%

Small-Scale Desalination Plant Driven by Solar Energy for Isolated Communities

Liponi

¹

,

Tempesti

²

,

Baccioli

³

et al. 2020

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In the last years, an increasing number of countries has been affected by water shortage. Seawater desalination driven by solar energy, which is usually available in arid regions, might be a solution to satisfy the freshwater demand. In this study, the feasibility of a stand-alone multi-effect desalination (MED) plant driven by solar energy for an isolated community was studied. The system was made up of a solar field, a MED unit, and a thermal storage that mitigated solar energy fluctuations. Simulations with different top brine temperature and inclination and number of the solar panels were carried out in Matlab and Aspen Plus on an hourly basis by considering one typical meteorological year for ambient temperature and solar radiation. Two different sources of electrical energy were considered: A photovoltaic (PV) field and a diesel generator. The results were compared from an energetic and economic point of view, by considering the adoption of plastic as a material for MED heat exchangers. The maximum water production was obtained with December as the design month. Polytetrafluoroethylene heat exchangers allowed the cost of water to be reduced up to 9.5% compared to conventional exchangers. The lowest cost of water (7.09 $/m3) was obtained with September as the design month and a tilt angle of 45° with the PV field as the electrical power source.

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“…On the second topic, MED process optimization has been focused on the preheating of water entering the system and evaporation by spraying. The configurations that implemented seawater preheating increased the performance ratio by up to 10% [51], even recording an average daily performance ratio of 2.5 and an average specific thermal energy consumption of 831 kJ/Kg, using thermal storage tanks and solar collectors [52]. According to the conducted simulations, with the use of the Spray Evaporation Tank, high evaporation efficiencies can be achieved if the required injection/spray parameters, the correct ratio between the water droplet size, and the fall distance are used in conjunction with the temperature of the warm air vapor [53,54].…”

Section: Multi Effect Distillation (Med)mentioning

confidence: 99%

Commercial Thermal Technologies for Desalination of Water from Renewable Energies: A State of the Art Review

Feria-Díaz

¹

,

López-Méndez

²

,

Rodríguez-Miranda

³

et al. 2021

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Thermal desalination is yet a reliable technology in the treatment of brackish water and seawater; however, its demanding high energy requirements have lagged it compared to other non-thermal technologies such as reverse osmosis. This review provides an outline of the development and trends of the three most commercially used thermal or phase change technologies worldwide: Multi Effect Distillation (MED), Multi Stage Flash (MSF), and Vapor Compression Distillation (VCD). First, state of water stress suffered by regions with little fresh water availability and existing desalination technologies that could become an alternative solution are shown. The most recent studies published for each commercial thermal technology are presented, focusing on optimizing the desalination process, improving efficiencies, and reducing energy demands. Then, an overview of the use of renewable energy and its potential for integration into both commercial and non-commercial desalination systems is shown. Finally, research trends and their orientation towards hybridization of technologies and use of renewable energies as a relevant alternative to the current problems of brackish water desalination are discussed. This reflective and updated review will help researchers to have a detailed state of the art of the subject and to have a starting point for their research, since current advances and trends on thermal desalination are shown.

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“…In the MED process optimization, numerical algorithms have been used, through computational mathematical models in steady state [43,59,72,73,77] [40,[64][65][66][67][68][69]. On the other hand, several authors suggest increasing the number of stages or effects in MED plants between 16 and 17 to optimize the process [36,39,45] and other investigations recommended preheating the seawater before feeding the MED [35,37,81]. Several investigations have been carried out in the Solar Platform of Almeria, attached to the Center for Energy, Environmental and Technological Research (CIEMAT) of Spain, focused on the optimization of MED processes, through mathematical modeling with data from experimental prototypes [43, 72-74, 78, 79], heat recovery and exergy [44,50,51,57,63,75]; and by hybridization with thermal vapor compression technologies [69].…”

Section: Thu Et Al 2013 [80]mentioning

confidence: 99%

Commercial Thermal Technologies for Desalination of Water from Renewable Energies: A State of the Art Review

Feria-Díaz¹,

López-Méndez²,

Sandoval-Herazo³

et al. 2021

Preprint

10

0

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Thermal desalination is yet a reliable technology in the treatment of brackish water and seawater; however, its demanding high energy requirements have lagged it compared to other non-thermal technologies such as reverse osmosis. This review provides an outline of the development and trends of the three most commercially used thermal or phase change technologies worldwide: Multi Effect Distillation (MED), Multi Stage Flash (MSF), and Vapor Compression Distillation (VCD). First, state of water stress suffered by regions with little fresh water availability and existing desalination technologies that could become an alternative solution are shown. The most recent studies published for each commercial thermal technology are presented, focusing on optimizing the desalination process, improving efficiencies, and reducing energy demands. Then, an overview of the use of renewable energy and its potential for integration into both commercial and non-commercial desalination systems is shown. Finally, research trends and their orientation towards hybridization of technologies and use of renewable energies as a relevant alternative to the current problems of brackish water desalination are discussed. This reflective and updated review will help researchers to have a detailed state of the art of the subject and to have a starting point for their research, since current advances and trends on thermal desalination are shown.

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Multi-effect distillation plants for small-scale seawater desalination: thermodynamic and economic improvement

Cited by 74 publications

References 34 publications

Small-Scale Desalination Plant Driven by Solar Energy for Isolated Communities

Small-Scale Desalination Plant Driven by Solar Energy for Isolated Communities

Commercial Thermal Technologies for Desalination of Water from Renewable Energies: A State of the Art Review

Commercial Thermal Technologies for Desalination of Water from Renewable Energies: A State of the Art Review

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