Open-source CFD model for optimization of forward osmosis and reverse osmosis membrane modules

Gruber, Mathias; Aslak, Ulf; Hélix-Nielsen, Claus

doi:10.1016/j.seppur.2015.12.017

Cited by 43 publications

(10 citation statements)

References 50 publications

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“…There are numerous reports on the dynamics of water when passing through polyamide membranes, − CNTs, − carbon composites, nanoporous graphene, − and graphene oxide , at nanoscales using nonequilibrium, equilibrium, or classical molecular dynamics. Computational fluid dynamics is a promising tool that has been employed for optimization of reverse osmosis (RO) modules and desalination membranes − at submicron scales. To have a general sense of the dynamics of water and particles as they flow in the whole assembly of new generation of desalination membrane setups, i.e., from the inlet all the way to the outlets, millimeter scale calculation is essential.…”

Section: Introductionmentioning

confidence: 99%

Engineering Water and Solute Dynamics and Maximal Use of CNT Surface Area for Efficient Water Desalination

et al. 2019

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While polymer-based membranes and the consistent plants and elements have long been considered and optimized, there are only few studies on optimization of the new generation of carbon-based porous membranes for water desalination. By modeling the elements and their corresponding parameters in a vertical configuration via COMSOL Multiphysics software, an experimental setup was modified that contained various bare and carbon nanotube (CNT)-covered microprocessed porous membranes in parallel and in series. Several design parameters such as inlet pressure, length of outlet, vertical distance of the parallel membranes, and horizontal distances of the series membranes were optimized. Taking advantage of the uttermost surface area of CNTs and the engineered particle trajectory, almost 90% NaCl rejection and 97% Allura red rejection were obtained with very high permeation values. Considering microsized outlets, the results of particle rejections are outstanding owing to the smart design of the setup. The results of this work can be extended to larger and smaller scales up to the point where the governing equations still hold.

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Section: Introductionmentioning

confidence: 99%

Engineering Water and Solute Dynamics and Maximal Use of CNT Surface Area for Efficient Water Desalination

et al. 2019

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“…Both experimental and computational fluid dynamics, working at the module scale, demonstrated the need to improve the understanding of process limitations that could be affected both by channel design and pressure balance in FO modules [ 237 , 244 , 245 , 246 , 247 , 248 , 249 , 250 , 251 , 252 ]. Further studies are required with specific focus on the concentration process with regard to practical operation and limitations.…”

Section: Tuning Fo Process To Tackle Current Limitations For Optimmentioning

confidence: 99%

Forward Osmosis as Concentration Process: Review of Opportunities and Challenges

et al. 2020

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In the past few years, osmotic membrane systems, such as forward osmosis (FO), have gained popularity as “soft” concentration processes. FO has unique properties by combining high rejection rate and low fouling propensity and can be operated without significant pressure or temperature gradient, and therefore can be considered as a potential candidate for a broad range of concentration applications where current technologies still suffer from critical limitations. This review extensively compiles and critically assesses recent considerations of FO as a concentration process for applications, including food and beverages, organics value added compounds, water reuse and nutrients recovery, treatment of waste streams and brine management. Specific requirements for the concentration process regarding the evaluation of concentration factor, modules and design and process operation, draw selection and fouling aspects are also described. Encouraging potential is demonstrated to concentrate streams more than 20-fold with high rejection rate of most compounds and preservation of added value products. For applications dealing with highly concentrated or complex streams, FO still features lower propensity to fouling compared to other membranes technologies along with good versatility and robustness. However, further assessments on lab and pilot scales are expected to better define the achievable concentration factor, rejection and effective concentration of valuable compounds and to clearly demonstrate process limitations (such as fouling or clogging) when reaching high concentration rate. Another important consideration is the draw solution selection and its recovery that should be in line with application needs (i.e., food compatible draw for food and beverage applications, high osmotic pressure for brine management, etc.) and be economically competitive.

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“…The model described in this paper is based on the open source toolkit OpenFOAM (Open Field Operation and Manipulation) [10,19,20,26]. The implementation of the model has been performed in two steps (i) implementation of the solver for the governing equation and (ii) implementation of proper boundary condition at the membrane surface.…”

Section: Model Developmentmentioning

confidence: 99%

“…Convective and diffusive fluxes must be balanced on both sides of the membrane. Taking into account that not all salts permeate through the membrane, the rejection of salt is considered and defined as [10,16,20,21,26]. This is used to determine the permeate concentra tion.…”

Section: Solution Diffusion Model and Boundary Conditionsmentioning

confidence: 99%

“…Computational fluid dynamics (CFD) has been used predominantly for investigating the influence of different flow regimes on concentra tion polarization and fouling control [18,19]. Several studies were carried out to optimize the membrane module design, in particular, the spacer configuration and orientation [10,20,21]. From these studies it was concluded that the zigzag spacer is the most efficient for the SWM [16,19,22].…”

Section: Introductionmentioning

confidence: 99%

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Renewable energy powered membrane technology: Computational fluid dynamics evaluation of system performance with variable module size and fluctuating energy

Onorato

Gaedtke

Kespe

et al. 2019

Separation and Purification Technology

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Renewable energy powered membrane systems operate with fluctuating energy. Such fluctuations affect pressure and feed flow and as such the hydrodynamic conditions in a membrane system. Hydrodynamic variations alter the membrane surface concentration and boundary layer thickness which in turn determines permeate water quality. In this work this is calculated using computational fluid dynamics (CFD) for the three most predominant energy levels obtained during such fluctuations and compared with experimental data. A 2D-CFD simulation was performed using OpenFOAM to calculate the wall concentration and boundary layer thickness over the length of a module. The influence of module type was investigated using two system configurations, namely three 2.5″ modules in series (BW30-2540 or NF270-2540) and one 4″ module (BW30-4040 and NF270-4040) with similar total membrane areas. Energy levels were extracted from experimental data at three solar irradiance, maximum intensity (1 kW/m 2), light cloud (360 W/m 2) and heavy cloud periods (190 W/m 2). At the highest energy level, in the system with three 2.5″ modules the wall concentration was closer to the bulk concentration due to the higher flow velocity in a smaller channel. The resulting boundary layer thickness for BW30 was constant and almost zero. At the medium energy level, the simulation results show that the permeate flux decreased significantly due to the lower pressure and for the BW30 it was almost zero due to the low pressure. At the lowest energy level, the feed pressure was well below the osmotic pressure and no permeation was possible. Results from this study show that the model is able to describe the filtration process in spiral wound membrane modules under fluctuating energy conditions. Further investigations on the possibility to improve the boundary conditions of the model are required.

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Open-source CFD model for optimization of forward osmosis and reverse osmosis membrane modules

Cited by 43 publications

References 50 publications

Engineering Water and Solute Dynamics and Maximal Use of CNT Surface Area for Efficient Water Desalination

Engineering Water and Solute Dynamics and Maximal Use of CNT Surface Area for Efficient Water Desalination

Forward Osmosis as Concentration Process: Review of Opportunities and Challenges

Renewable energy powered membrane technology: Computational fluid dynamics evaluation of system performance with variable module size and fluctuating energy

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