scholarly journals Process simulation of modelled reverse osmosis for desalination of seawater

Author(s):  
Nurudeen Salahudeen

Abstract Model equations for prediction of process parameters of reverse osmosis for desalination of seawater were developed via mathematical derivation from basic equations for reverse osmosis process. A model equation relating the interfacial solute concentration () with the process pressure difference () was developed. Taking the of a reverse osmosis as the basic independent variable, further model equations relating other process parameters such as the solute concentration polarity , water flux , osmotic pressure , water output rate (q), power density (Pd) and specific energy consumption (SEC) were developed. Simulation of a hypothetical reverse osmosis data using Microsoft Excel Worksheet and a Microsoft Windows 10 on a 64-bit operating system was carried out. Simulation results showed that the optimum fluid bulk concentration was = 0.0004 mole/cm3. The optimum rate of increase in the solute rejection factor per unit rise in ΔP was 0.45%. The optimum solute rejection factor was 97.6%. The optimum water output rate, specific energy consumption and power density were 103.2 L/h, 3.65 kWh/m3 and 6.09 W/m2, respectively.

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 173
Author(s):  
Abdeljalil Chougradi ◽  
François Zaviska ◽  
Ahmed Abed ◽  
Jérôme Harmand ◽  
Jamal-Eddine Jellal ◽  
...  

As world demand for clean water increases, reverse osmosis (RO) desalination has emerged as an attractive solution. Continuous RO is the most used desalination technology today. However, a new generation of configurations, working in unsteady-state feed concentration and pressure, have gained more attention recently, including the batch RO process. Our work presents a mathematical modeling for batch RO that offers the possibility of monitoring all variables of the process, including specific energy consumption, as a function of time and the recovery ratio. Validation is achieved by comparison with data from the experimental set-up and an existing model in the literature. Energetic comparison with continuous RO processes confirms that batch RO can be more energy efficient than can continuous RO, especially at a higher recovery ratio. It used, at recovery, 31% less energy for seawater and 19% less energy for brackish water. Modeling also proves that the batch RO process does not have to function under constant flux to deliver good energetic performance. In fact, under a linear pressure profile, batch RO can still deliver better energetic performance than can a continuous configuration. The parameters analysis shows that salinity, pump and energy recovery devices efficiencies are directly linked to the energy demand. While increasing feed volume has a limited effect after a certain volume due to dilution, it also shows, interestingly, a recovery ratio interval in which feed volume does not affect specific energy consumption.


Water ◽  
2016 ◽  
Vol 8 (12) ◽  
pp. 601 ◽  
Author(s):  
Ashlynn Stillwell ◽  
Michael Webber

2020 ◽  
Vol 20 (8) ◽  
pp. 3096-3106
Author(s):  
Simeng Li ◽  
Karla Duran ◽  
Saied Delagah ◽  
Joe Mouawad ◽  
Xudong Jia ◽  
...  

Abstract Reverse osmosis (RO) technologies have been widely implemented around the world to address the rising severity of freshwater scarcity. As desalination capacity increases, reducing the energy consumption of the RO process per permeate volume (i.e., specific energy consumption) is of particular importance. In this study, numerical models are used to characterize and compare the energy efficiency of one-stage continuous RO, multi-stage continuous RO, and closed-circuit RO (CCRO) processes. The simulated results across a broad range of feed salinity (5,000–50,000 ppm, i.e., 5–50 g kg−1) and recovery (40%–95%) demonstrate that, compared with the most common one-stage continuous RO, two-stage and three-stage continuous RO can reduce the specific energy consumption by up to 40.9% and 53.6%, respectively, while one-stage and two-stage CCRO can lead to 45.0% and 67.5% reduction, respectively. The differences in energy efficiencies of various RO configurations are more salient when desalinating high-salinity feed at a high recovery ratio. From the standpoints of energy saving and capital cost, the simulated results indicate that multi-stage CCRO is an optimal desalination process with great potential for practical implementation.


Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 32
Author(s):  
MhdAmmar Hafiz ◽  
Alaa H. Hawari ◽  
Radwan Alfahel ◽  
Mohammad K. Hassan ◽  
Ali Altaee

This study compares the performance of nanofiltration (NF) and reverse osmosis (RO) for the reclamation of ultrafiltered municipal wastewater for irrigation of food crops. RO and NF technologies were evaluated at different applied pressures; the performance of each technology was evaluated in terms of water flux, recovery rate, specific energy consumption and quality of permeate. It was found that the permeate from the reverse osmosis (RO) process complied with Food and Agriculture Organization (FAO) standards at pressures applied between 10 and 18 bar. At an applied pressure of 20 bar, the permeate quality did not comply with irrigation water standards in terms of chloride, sodium and calcium concentration. It was found that nanofiltration process was not suitable for the reclamation of wastewater as the concentration of chloride, sodium and calcium exceeded the allowable limits at all applied pressures. In the reverse osmosis process, the highest recovery rate was 36%, which was achieved at a pressure of 16 bar. The specific energy consumption at this applied pressure was 0.56 kWh/m3. The lowest specific energy of 0.46 kWh/m3 was achieved at an applied pressure of 12 bar with a water recovery rate of 32.7%.


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