Reducing specific energy consumption in Reverse Osmosis (RO) water desalination: An analysis from first principles

Li, Mingheng

doi:10.1016/j.desal.2011.03.031

Cited by 112 publications

(67 citation statements)

References 31 publications

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“…There have been several studies performed on simulating energy consumption in RO desalination using mathematical models and simulation environments [1,2,[41][42][43][44][45][46], which is not surprising given the wide application of RO in the desalination industry. On the other hand, there are at present no such simulation models and software for FO desalination processes, and so no single piece of software which contains library unit operations for both RO and FO processes together.…”

Section: Simulation Toolsmentioning

confidence: 99%

Energy consumption for desalination — A comparison of forward osmosis with reverse osmosis, and the potential for perfect membranes

2016

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Section: Simulation Toolsmentioning

confidence: 99%

Energy consumption for desalination — A comparison of forward osmosis with reverse osmosis, and the potential for perfect membranes

2016

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“…In SWRO applications, Pelton turbines (typical energy savings of 35% to 42% compared to a baseline without energy recovery equipment) for energy recovery are generally applicable for ≤5000 m 3 /day capacity, while isobaric energy recovery devices (typical energy savings of 55% to 60%) are suited for >5000 m 3 /day [42]. Approaches to reduce SEC include use of high permeability membranes [43], use of energy recovery devices, intermediate chemical demineralization, use of renewable energy, and optimal process configuration [44]. With advanced materials, increased water-solute selectivity has become more important than additional increases in water permeability, since increasing permeability negligibly decreases SEC [45][46][47].…”

Section: Technologymentioning

confidence: 99%

Predicting the Specific Energy Consumption of Reverse Osmosis Desalination

Stillwell

Webber

2016

Water

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Desalination is often considered an approach for mitigating water stress. Despite the abundance of saline water worldwide, additional energy consumption and increased costs present barriers to widespread deployment of desalination as a municipal water supply. Specific energy consumption (SEC) is a common measure of the energy use in desalination processes, and depends on many operational and water quality factors. We completed multiple linear regression and relative importance statistical analyses of factors affecting SEC using both small-scale meta-data and municipal-scale empirical data to predict the energy consumption of desalination. Statistically significant results show water quality and initial year of operations to be significant and important factors in estimating SEC, explaining over 80% of the variation in SEC. More recent initial year of operations, lower salinity raw water, and higher salinity product water accurately predict lower values of SEC. Economic analysis revealed a weak statistical relationship between SEC and cost of water production. Analysis of associated greenhouse gas (GHG) emissions revealed important considerations of both electricity source and SEC in estimating the GHG-related sustainability of desalination. Results of our statistical analyses can aid decision-makers by predicting the SEC of desalination to a reasonable degree of accuracy with limited data.

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“…Previous studies have shown that staged RO has potential for significant energy savings 7,[15][16][17][18] . These studies demonstrate the en-50 ergetic benefits of staged RO for a range of feed salinities and recovery ratios.…”

Section: Previous Workmentioning

confidence: 99%

Saving energy with an optimized two-stage reverse osmosis system

Wei

McGovern

Lienhard

2017

Environ. Sci.: Water Res. Technol.

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In a two-stage reverse osmosis (RO) system of finite size, there are two degrees of freedom not present in a single-stage RO system: distribution of RO elements between the two stages (system design), and feed pressures (system operation). In this study, we investigate the optimal system design and operation of a two-stage RO system with a mass-balance model and establish a lower bound for the energy savings achieved by the optimized two-stage system compared to a singlestage system. A two-stage RO system may consume more or less energy than a single-stage RO system of the same size and freshwater productivity, depending on the first-stage feed pressure and second-stage feed pressure. To minimize energy consumption, feed pressures should be chosen to minimize spatial variance in flux. The optimal element configuration places at least half the elements in the first stage; the exact configuration depends on feed salinity, recovery ratio, and membrane permeability. The greatest energy savings are achieved with a two-stage RO system that has both optimal element configuration and feed pressures. More energy can be saved by adding a stage when the thermodynamic least work of separation is larger. For a given feed salinity, energy savings from adding a second stage grow as recovery ratio increases. Brackish water feeds must be taken to high recovery ratios to achieve substantial energy savings; comparable savings can be achieved at lower recovery ratios for higher salinity feeds. We find that significant energy can be saved with the simplest two-stage RO design, at a system flux similar to today's RO plants and accounting for the effects of concentration polarization. Nomenclature

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Reducing specific energy consumption in Reverse Osmosis (RO) water desalination: An analysis from first principles

Cited by 112 publications

References 31 publications

Energy consumption for desalination — A comparison of forward osmosis with reverse osmosis, and the potential for perfect membranes

Energy consumption for desalination — A comparison of forward osmosis with reverse osmosis, and the potential for perfect membranes

Predicting the Specific Energy Consumption of Reverse Osmosis Desalination

Saving energy with an optimized two-stage reverse osmosis system

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