Consideration of energy savings in SWRO

Bartels, Craig; Andes, Keith

doi:10.1080/19443994.2012.700038

Cited by 19 publications

(13 citation statements)

References 2 publications

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“…An added benefit of the sCS 2 process is the production of softened water, an excellent feed for desalination plants. Currently, the energy cost of desalinating seawater can be estimated as 3.5 kWh per t of water, considering that seawater reverse osmosis (SWRO) requires 2–2.5 kWh per m 3 and the pretreatment steps, which is water softening, consume 0.3–1.0 kWh per m 3 of seawater . Combining CO 2 mineralization-based pretreatment and desalination can lead to an energy use that is 9% lower than the total energy consumption of the two processes, operating separately.…”

Section: Resultsmentioning

confidence: 99%

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO₂Management

Plante

Simonetti

Wang

et al. 2021

ACS Sustainable Chem. Eng.

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This perspective proposes a potential pathway to diminish atmospheric CO2 accumulations which is distinct from traditional carbon capture and geological sequestration strategies and from existing negative emissions technologies (NETs). Unlike conventional sorbent- or solvent-based CO2 capture processes where substantial energy expenditures are associated with demixing and desorbing CO2, the single-step carbon sequestration and storage (sCS2) approach relies on electrolytic carbonate mineral precipitation using renewable energy within a simple and scalable process design. Although numerous approaches have implied electrolysis for carbon management, the sCS2 approach is unique in the following ways: (1) CO2 mineralization for promoting solid carbonate formation: The thermodynamic and kinetic barriers to carbonate precipitation are overcome by direct and in situ electrochemical forcing to stabilize dissolved inorganic carbon and divalent cations [Ca,Mg] to form carbonate minerals. (2) Flow-through membraneless electrolysis: A flowing electrolyte (seawater) is dissociated while in motion. The process utilizes cost-effective mesh electrodes while also decreasing the number of components and assembly steps and reducing the risk of device failure. (3) Integrated electrolytic reactor–rotary drum filter: An electroactive thin-film mesh cathode (eTFC) is suggested to be integrated within a rotary drum filter configuration, allowing for the filtration of dilute and polydispersed mineral precipitates at a low energy cost. These attributes render sCS2 as an approach worthy of more detailed evaluation, development, and scaling for global-scale carbon management.

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Section: Resultsmentioning

confidence: 99%

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO₂Management

Plante

Simonetti

Wang

et al. 2021

ACS Sustainable Chem. Eng.

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“…38,39 A small decrease in membrane area may be possible without an increased level of fouling by incorporating high-permeability elements only at the back end of an RO module, where the driving force is relatively low because of the increased osmotic pressure of the retained feed. 34,40 Forward Osmosis. FO has enabled membrane-based desalination of difficult to treat feed-waters, particularly those with high total dissolved solids (TDS), which cannot be treated by RO.…”

Section: ■ Relative Insignificance Of High Water Permeabilitymentioning

confidence: 99%

The Critical Need for Increased Selectivity, Not Increased Water Permeability, for Desalination Membranes

Werber

Deshmukh

Elimelech

2016

Environ. Sci. Technol. Lett.

568

429

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Desalination membranes are essential for the treatment of unconventional water sources, such as seawater and wastewater, to alleviate water scarcity. Promising research efforts on novel membrane materials may yield significant performance gains over state-of-the-art thin-film composite (TFC) membranes, which are constrained by the permeability–selectivity trade-off. However, little guidance currently exists on the practical impact of such performance gains, namely enhanced water permeability or enhanced water–solute selectivity. In this critical review, we first discuss the performance of current TFC membranes. We then highlight and provide context for recent module-scale modeling studies that have found limited impact of increased water permeability on the efficiency of desalination processes. Next we cover several important examples of water treatment processes in which inadequate membrane selectivity hinders process efficacy. We conclude with a brief discussion of how the need for enhanced selectivity may influence the design strategies of future membranes.

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“…ERDs are crucial in SWRO for decreasing energy usage by recovering energy from the high-pressure brine [14]. Essentially all new SWRO plants employ ERDs, typically isobaric work exchangers such as the DWEER device from Flowserve Corporation (Irving, TX) and the PX Pressure Exchanger from Energy Recovery Inc. (San Leandro, CA), each of which can recover energy from the brine at efficiencies up to 98% [3,[15][16][17]. While ERDs have markedly decreased the energy consumption of SWRO plants, one-stage RO is still far from optimal from an energy perspective.…”

Section: Staged Reverse Osmosismentioning

confidence: 99%

Can batch or semi-batch processes save energy in reverse-osmosis desalination?

2017

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Energy savings in reverse osmosis (RO) are highly constrained by the design of conventional processes, for which the minimum practical energy of desalination substantially exceeds the thermodynamic minimum. Batch processes can theoretically approach the thermodynamic minimum, suggesting the possibility for further energy savings. In this study, we aim to quantify what energy reductions may be possible for batch-like processes when process inefficiencies such as frictional losses and concentration polarization are included. We first introduce a practical batch process that utilizes energy recovery devices and an unpressurized feed tank. We also consider a less practical pressurized-tank scenario, as well as semi-batch (closed-circuit) RO. We then derive analytical approximations and conduct numerical modeling to compare the energy requirements of batch, semi-batch, and staged RO processes under realistic conditions. Through this analysis, we find that practical batch-like processes and processes with increased staging offer comparable and significant energy savings. For example, semi-batch RO and twostage RO would save 13% and 15% energy, respectively, over one-stage seawater RO at 50% recovery. We conclude with a discussion of other important factors, such as capital costs and process robustness and flexibility, that will affect the implementation of batch, semi-batch, and staged processes.

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Consideration of energy savings in SWRO

Cited by 19 publications

References 2 publications

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO₂Management

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO₂Management

The Critical Need for Increased Selectivity, Not Increased Water Permeability, for Desalination Membranes

Can batch or semi-batch processes save energy in reverse-osmosis desalination?

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Consideration of energy savings in SWRO

Cited by 19 publications

References 2 publications

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO2Management

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO2Management

The Critical Need for Increased Selectivity, Not Increased Water Permeability, for Desalination Membranes

Can batch or semi-batch processes save energy in reverse-osmosis desalination?

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Product

Resources

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Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO₂Management

Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO₂Management