Effect of the operating temperature on hydrodynamics and membrane parameters in pressure retarded osmosis

Touati, Khaled; Tadeo, Fernando; Hänel, C.; Schiestel, Thomas

doi:10.1080/19443994.2015.1039600

Cited by 27 publications

(21 citation statements)

References 28 publications

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“…Therefore, the osmotic pressure difference decreases and reduces the performance of PRO. Besides that, previous works had shown that PRO membrane performance is limited by several limiting factors [26,27]. In fact, with a realistic membrane and imperfect hydrodynamics, three phenomena occur to reduce the trans-membrane water flux, as shown in Fig.S4.…”

Section: Modeling the Energy Consumption Of The Swro-pro System Undermentioning

confidence: 95%

“…Their local values should be considered for accurate modeling. These spatial variations can be accounted for either by taking an average of inlet and outlet variables, or by considering the membrane as a finite difference model[26,27]. To develop a model for full-scale PRO applications, the flat sheet membrane area is divided into segments perpendicular to the water flow, evaluating flow conditions at specific points along the membrane module.…”

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confidence: 99%

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Energy recovery from two-stage SWRO plant using PRO without external freshwater feed stream: Theoretical analysis

et al. 2017

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Research into pressure retarded osmosis (PRO) as a method to extract energy from salinity gradients is on the rise. Seawater Reverse Osmosis (SWRO) is now a leading technology in the desalination industry worldwide, in both small and large scale applications, due to the remarkable improvements in membrane performance and associated energy efficiency. Nonetheless, SWRO desalination is inherently more energy intensive when compared to conventional fresh water treatment. The integration of PRO with SWRO systems is studied in terms of energy consumption and effluent changes. For this, two novel integration designs are evaluated, with SWRO-PRO specific energy consumption being modeled using SWRO conditions at the thermodynamic restriction, and a developed PRO model. The results show lower SWRO energy consumption for both configurations, with a reduction in consumption of 12% to 18%, depending on the RO recovery ratios. Lastly, the effect of the initial flow ratio on the dilution factor has been studied. To do so, the dilution was modeled and studied for different operating conditions. It was found that detrimental effects severely reduce the dilution, especially the internal concentration polarization, which induces a decrease of energy recovery when using the PRO process.

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Section: Modeling the Energy Consumption Of The Swro-pro System Undermentioning

confidence: 95%

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confidence: 99%

Energy recovery from two-stage SWRO plant using PRO without external freshwater feed stream: Theoretical analysis

et al. 2017

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“…In fact, according to the van 't Hoff equation (π = βCRT), there is a direct proportional relationship between osmotic pressure and the temperature. Although the osmotic pressure is not proportional to the concentration if the solutions are highly concentrated, there is still an assumption of the proportionality between the osmotic pressure and the temperature [116]. Variation in the thermodynamic properties not only affects the water flux but also influences membrane fouling and solute rejection/diffusion [117].…”

Section: Temperaturementioning

confidence: 99%

Factors Affecting the Performance of Membrane Osmotic Processes for Bioenergy Development

et al. 2020

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Forward osmosis (FO) and pressure-retarded osmosis (PRO) have gained attention recently as potential processes to solve water and energy scarcity problems with advantages over pressure-driven membrane processes. These processes can be designed to produce bioenergy and clean water at the same time (i.e., wastewater treatment with power generation). Despite having significant technological advancement, these bioenergy processes are yet to be implemented in full scale and commercialized due to its relatively low performance. Hence, massive and extensive research has been carried out to evaluate the variables in FO and PRO processes such as osmotic membrane, feed solutions, draw solutions, and operating conditions in order to maximize the outcomes, which include water flux and power density. However, these research findings have not been summarized and properly reviewed. The key parts of this review are to discuss the factors influencing the performance of FO and PRO with respective resulting effects and to determine the research gaps in their optimization with the aim of further improving these bioenergy processes and commercializing them in various industrial applications.

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“…The term exp( Jwr k F ) condenses the effect of concentrative ECP. There are some other suggested models developed based on convection-diffusion theory [60] or considering the effect of fouling layer on the mass transport equations [61]. Some models have been modified for hollow fiber membranes to consider the spatial parameters with the change of geometry for the membrane [62,63].…”

Section: Bui Modelmentioning

confidence: 99%

Modeling and simulation of the dual stage pressure retarded osmosis systems

Soltani

Struchtrup

2019

Desalination

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Utilization of renewable energy sources, as an approach to reduce greenhouse gas (GHG) emissions, have been globally popular in the last few decades. Among renewable energy sources, pressure retarded osmosis (PRO) has been scrutinized by scientists since the mid 70's. However, even today, the existing river-sea PRO systems can only marginally meet the generally approved criterion of 5 W/m 2 power density, a threshold for an economically feasible PRO system. As an approach to increase the performance of PRO systems, multi-staging of PRO modules are investigated. A mathematical model of the scaled up PRO process is proposed with consideration for internal and external concentration polarization, reverse salt flux, and spatial variations along the membrane. A thermodynamic model is also developed with consideration for entropy generation and losses in the process. It predicts the percentile of each work loss source compared to the net work in the system. Several configurations of dual stage PRO system are presented and compared to single stage PRO. The comparison is based on three proposed target functions of power density (PD), specific energy (SE), and work per drawn freshwater (W drawn). Applied hydraulic pressures and flow rates of draw and feed solutions are optimized for maximizing the target functions. The results indicate that overall performance of the system could be improved by up to 8 % with a dual stage PRO in the case of SE. The system iv performance is not improved by depressurizing the draw solution before the second module in cases of SE and W drawn. The thermodynamic analysis demonstrate the contribution of each work loss and justify the reason of diminishing the net work over the losses. The effect of membrane area and membrane characteristics on the SE target function is also investigated. The distribution of membrane area in each module depends on the selected configuration and inlet draw solution. In the dual stage systems, the SE value increases up to 14% by improving the membrane characteristics. Reducing the salt rejection coefficient (B) is the most effective membrane characteristic in our configurations. Replacing seawater with RO brine in draw solution results in a significant improvement in SE values.

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Effect of the operating temperature on hydrodynamics and membrane parameters in pressure retarded osmosis

Cited by 27 publications

References 28 publications

Energy recovery from two-stage SWRO plant using PRO without external freshwater feed stream: Theoretical analysis

Energy recovery from two-stage SWRO plant using PRO without external freshwater feed stream: Theoretical analysis

Factors Affecting the Performance of Membrane Osmotic Processes for Bioenergy Development

Modeling and simulation of the dual stage pressure retarded osmosis systems

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