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

Mazlan, Nur Muna; Peshev, D.; Livingston, Andrew G.

doi:10.1016/j.desal.2015.08.011

Cited by 170 publications

(72 citation statements)

References 57 publications

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“…Mazlan et al compared the energy consumption of FO with nanofiltration (NF) or ultrafiltration (UF) draw solute recovery and reverse osmosis (RO) [21]. The results suggest that there is practically no difference in the specific energy consumption of FO-NF (or FO-UF) and RO even if the membrane is theoretically perfect.…”

Section: Introductionmentioning

confidence: 99%

A Thermodynamical Approach for Evaluating Energy Consumption of the Forward Osmosis Process Using Various Draw Solutes

Zeng

Wang

2017

Water

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Abstract:The forward-osmosis (FO) processes have received much attention in past years as an energy saving desalination process. A typical FO process should inclu de a draw solute recovery step which contributes to the main operation costs of the process. Therefore, investigating the energy consumption is very important for the development and employment of the forward osmosis process. In this work, NH 3 -CO 2 , Na 2 SO 4 , propylene glycol mono-butyl ether, and dipropylamine were selected as draw solutes. The FO processes of different draw solute recovery approaches were simulated by Aspen PlusTM with a customized FO unit model. The electrolyte Non-Random Two-Liquid (Electrolyte-NRTL) and Universal Quasi Chemical (UNIQUAC) models were employed to calculate the thermodynamic properties of the feed and draw solutions. The simulation results indicated that the FO performance decreased under high feed concentration, while the energy consumption was improved at high draw solution concentration. The FO process using Na 2 SO 4 showed the lowest energy consumption, followed by NH 3 -CO 2 , and dipropylamine. The propylene glycol mono-butyl ether process exhibited the highest energy consumption due to its low solubility in water. Finally, in order to compare the equivalent work of the FO processes, the thermal energy requirements were converted to electrical work.

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Section: Introductionmentioning

confidence: 99%

A Thermodynamical Approach for Evaluating Energy Consumption of the Forward Osmosis Process Using Various Draw Solutes

Zeng

Wang

2017

Water

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“…It may not be the most popular method of treating water, but it is becoming an emerging topic in the water processing industry. There are several distinctive features of FO desalination and wastewater treatment, when compared to the more conventional methods of reverse osmosis which includes: (i) FO has a lower fouling propensity of the membrane used, this is due to the low pressure required for the process, in which the velocity of the fluids are small, (ii) A so called 'perfect' feed to the more energy intensive reverse osmosis and the double membrane barrier between feed stream and draw stream, (iii) FO has the ability to recycle the additives used in the draw solutions, such as anti-scalants, whilst significantly reducing any contaminants such as Boron that may be otherwise difficult or costly to remove from the product stream and (iv) the energy consumption of FO when compared to conventional methods is substantially lower, in particular where it is deployed on more challenging feedwater, where a conventional RO plant would otherwise operate at lower recovery than the regeneration step (Miller, Evans 2006;Mazlan et al 2016). …”

Section: Forward Osmosis (Fo)mentioning

confidence: 99%

Evaluating the Performance of Low-Energy Feed Forward Osmosis System for Desalination using Impaired and Saline Water Sources

Tota-Maharaj

2017

Proccedings of 10th International Conference "Environmental Engineering"

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Abstract. Forward Osmosis (FO) is a natural process of treating water or wastewater due to the difference in osmotic pressures. FO is a membrane separation technology, applicable to food processing, industrial wastewater treatment and seawater or brackish water desalination. The phenomena of FO processes occur whereby water molecules are driven across a semipermeable membrane by an osmotic pressure gradient that is generated from a higher concentrate draw solution. FO processes can recover potable water resources from wastewater streams through the flow of pure water from a lower concentrated feed solution towards higher concentrated draw solutions leaving behind pollutants, impurities, and salts in the semi-permeable membrane. This paper assesses the design, build and testing of a laboratory scaled Feed Forward Osmosis (FFO) system for treating river water collected from the River Medway, Kent, England. The FO process was a highly effective form of river water treatment and able to treat the River Water with high rejection rates of solutes (>90%). Experimental results showed that the FFO system can achieve a better performance when the molarity of the draw solution is higher. The average solute rejection rate of the FO membrane for both inorganic and organic compounds was 94.83 %. Moreover, the operation of the forward osmosis membrane illustrated that it has a lower fouling propensity and higher solute rejection capabilities. The pilot scaled FFO system has the ability for greater salt rejection and lower electronic conductivity levels which resulted from the successful desalination of river water. A sodium chloride (NaCl) or saltwater draw solution performed positively in inducing higher osmotic pressures with a substantial effect of lower energy requirements for the system. Lower energy consumptions of the FFO system allow similar water treatment possibilities with energy savings potential. The FFO system showed to be an environmentally viable and economically feasible river water treatment technology.

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“…For SWRO, as for many other desalination technologies, the SEC of commercial systems has decreased over time, dropping from an average of 20 kWh/m 3 in 1980 to 1.62 kWh/m 3 in 2005 [9]. While advances have been made in decreasing SEC, especially for RO operations, separating dissolved solids from water requires a minimum amount of energy, which is process-independent [29] but varies with system recovery [30][31][32]. The theoretical minimum SEC has been calculated based on thermodynamic constraints at approximately 1.06 kWh/m 3 for desalinating raw (incoming) water with total dissolved solids (TDS) concentration of 35,000 mg/L at 50% recovery (defined as the ratio of product water flow to raw water flow) [16,18,33].…”

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

Cited by 170 publications

References 57 publications

A Thermodynamical Approach for Evaluating Energy Consumption of the Forward Osmosis Process Using Various Draw Solutes

A Thermodynamical Approach for Evaluating Energy Consumption of the Forward Osmosis Process Using Various Draw Solutes

Evaluating the Performance of Low-Energy Feed Forward Osmosis System for Desalination using Impaired and Saline Water Sources

Predicting the Specific Energy Consumption of Reverse Osmosis Desalination

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