Optimal design of spacers in reverse osmosis

Haidari, A.H.; Heijman, S.G.J.; Meer, W.G.J. van der

doi:10.1016/j.seppur.2017.10.042

Cited by 112 publications

(57 citation statements)

References 164 publications

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“…The severity of CP is typically governed by the solute and membrane properties and the hydrodynamics (flow conditions, pressure, and geometry of the flow channel) of the RO process [40,41]. Although the aforementioned effects are severe, CP is considered to be reversible and can be mitigated by employing appropriate feed velocity, rotating or vibrating modules, reactive micro-mixing, pulsation, or feed spacers [40,[42][43][44][45][46].…”

Section: Effects Of Concentration Polarizationmentioning

confidence: 99%

Reverse osmosis desalination: A state-of-the-art review

et al. 2019

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Water scarcity is a grand challenge that has always stimulated research interests in finding effective means for pure water production. In this context, reverse osmosis (RO) is considered the leading and the most optimized membrane-based desalination process that is currently dominating the desalination market. In this review, various aspects of RO desalination are reviewed. Theories and models related to concentration polarization and membrane transport, as well as merits and drawbacks of these models in predicting polarization effects, are discussed. An updated review of studies related to membrane modules (plate and frame, tubular, spiral wound, and hollow fiber) and membrane characterization are provided. The review also discusses membrane cleaning and different pre-treatment technologies in place for RO desalination, such as feed-water pre-treatment and biocides. RO pre-treatment technologies, which include conventional (e.g., coagulationflocculation, media filtration, disinfection, scale inhibition) and non-conventional (e.g., MF, UF, and NF) are reviewed and their relative attributes are compared. As per the available literature, UF, MF and coagulation-flocculation are considered the most widely used pre-treatment technologies. In addition, this review discusses membrane fouling, which represents a serious challenge in RO processes due to its significant contribution to energy requirements and process economy (e.g., flux decline, permeate quality, membrane lifespan, increased feed pressure, increased pre-treatment and membrane maintenance cost). Different membrane fouling types, such as colloidal, organic, inorganic, and biological fouling, are addressed in this review. Principles of RO process design and the embedded economic and energy considerations are discussed. In general, cost of water desalination has dropped to values that made it a viable option, comparable even to conventional water treatment methods. Finally, an overview of hybrid RO desalination processes and the current challenges faced by RO desalination processes are presented and discussed.

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Section: Effects Of Concentration Polarizationmentioning

confidence: 99%

Reverse osmosis desalination: A state-of-the-art review

et al. 2019

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“…RO technology can produce fresh water by applying pressure which is higher than the osmotic pressure of raw water. The raw water source treated by RO may be divided into seawater, brackish water, and others [1,3,5,[7][8][9][10][11]. Seawater is the most used feed raw water source accounting for about 57.5% of the desalination capacity contracted between 2015 and June 2018, while brackish water accounts for 18.5% [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…In practical use of RO membranes, the spiral-wound membrane (SWM) element is usually selected as the configuration [11,18]. The SWM element is composed of RO membrane envelopes, feed spacers, permeate spacers and a permeate center pipe [11,[18][19][20]. The RO membrane envelopes, feed spacers and permeate spacers are spirally wound around the permeate center pipe, as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

How RO membrane permeability and other performance factors affect process cost and energy use: A review

2019

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Reverse osmosis (RO) technology has progressed steadily over the last few decades. Those gains were achieved through improvements in both RO membrane element performance and energy recovery technologies. However, some recent literature indicates that RO membrane water permeability is approaching performance limits imposed by transport processes and thermodynamic constraints. This paper reviews how RO membrane element performance affects the cost of RO processes, especially the specific energy consumption. RO membrane performance encompasses water permeability, salt permeability, and other some characteristics of the RO element. This paper considers not only conventional RO processes, but also the recently proposed closed-circuit RO and batch RO processes. Even if the membrane water permeability increases, little additional effect is found when the membrane water permeability exceeds around 3 LMH/bar for seawater RO and 8 LMH/bar for brackish water RO in conventional single-stage RO. Increasing membrane water permeability has the potential to decrease membrane surface area and associated costs. A major limitation of most existing literature is that performance is evaluation on in terms of the initial operating conditions. Chronological changes, such as result from fouling, must also be considered to accurately validate how membrane element performance affects RO cost.

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“…One of the main challenges to improve RO efficiency is related to decreasing specific energy consumption (SEC) [5,6] and the fouling effects on spiral-wound membrane modules (SWMMs) of RO. In recent years, several studies have proposed alternatives to improve the efficiency of the process, such as using new membrane materials [7][8][9] and optimizing the feed spacer geometry [10,11]. Generally, the studies related to new RO membrane materials have focused on improving certain membrane characteristics, namely their antifouling properties [12,13], the water permeability coefficient (A), and the solute permeability coefficient (B) [14].…”

Section: Introductionmentioning

confidence: 99%

“…Generally, the studies related to new RO membrane materials have focused on improving certain membrane characteristics, namely their antifouling properties [12,13], the water permeability coefficient (A), and the solute permeability coefficient (B) [14]. However, the feed spacers are an essential part of SWMMs and play an important role in the concentration polarization phenomena, the pressure drop along the membrane, and fouling [10,15,16].…”

Section: Introductionmentioning

confidence: 99%

Feed Spacer Geometries and Permeability Coefficients. Effect on the Performance in BWRO Spriral-Wound Membrane Modules

Ruiz-García

Nuez

2019

Water

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Reverse osmosis (RO) is the most widely used technology to desalinate brackish water and seawater. Significant efforts have been made in recent decades to improve RO efficiency. Feed spacer geometry design is a very important factor in RO membrane performance. In this work, correlations based on computational fluid dynamics and experimental work were applied in an algorithm to simulate the effect of different feed spacer geometries in full-scale brackish water reverse osmosis (BWRO) membranes with different permeability coefficients. The aim of this work was to evaluate the impact of feed spacers in conjunction with the permeability coefficients on membrane performance. The results showed a greater impact of feed spacer geometries in the membrane with the highest water permeability coefficient (A). Studying only one single element in a series, variations due to feed spacer geometries were observed in specific energy consumption ( S E C ) and permeate concentration ( C p ) of about 6.83% and 10.42%, respectively. Allowing the rolling of commercial membranes with different feed spacer geometries depending on the operating conditions could optimize the RO process.

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Optimal design of spacers in reverse osmosis

Cited by 112 publications

References 164 publications

Reverse osmosis desalination: A state-of-the-art review

Reverse osmosis desalination: A state-of-the-art review

How RO membrane permeability and other performance factors affect process cost and energy use: A review

Feed Spacer Geometries and Permeability Coefficients. Effect on the Performance in BWRO Spriral-Wound Membrane Modules

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