Spiral-wound Modules Research Articles

Stokes flow singularity at the junction between impermeable and porous walls

AbstractFor two-dimensional, creeping flow in a half-plane, we consider the singularity that arises at an abrupt transition in permeability from zero to a finite value along the wall, where the pressure is coupled to the seepage flux by Darcy’s law. This problem represents the junction between the impermeable wall of the inflow section and the porous membrane further downstream in a spiral-wound desalination module. On a macroscopic, outer length scale the singularity appears like a jump discontinuity in normal velocity, characterized by a non-integrable$1/ r$divergence of the pressure. This far-field solution is imposed as the boundary condition along a semicircular arc of dimensionless radius 30 (referred to the microscopic, inner length scale). A preliminary numerical solution (using a least-squares variant of the method of fundamental solutions) indicates a continuous normal velocity along the wall coupled with a weaker$1/ \sqrt{r} $singularity in the pressure. However, inconsistencies in the numerically imposed outer boundary condition indicate a very slow radial decay. We undertake asymptotic analysis to: (i) understand the radial decay behaviour; and (ii) find a more accurate far-field solution to impose as the outer boundary condition. Similarity solutions (involving a stream function that varies like some power of$r$) are insufficient to satisfy all boundary conditions along the wall, so we generalize these by introducing linear and quadratic terms in$\log r$. By iterating on the wall boundary conditions (analogous to the method of reflections), the outer asymptotic series is developed through second order. We then use a hybrid computational scheme in which the numerics are iteratively patched to the outer asymptotics, thereby determining two free coefficients in the latter. We also derive an inner asymptotic series and fit its free coefficient to the numerics at$r= 0. 01$. This enables evaluation of the singular flow field in the limit as$r\ensuremath{\rightarrow} 0$. Finally, a uniformly valid fit is obtained with analytical formulas. The singular flow field for a solid–porous abutment and the general Stokes flow solutions obtained in the asymptotic analysis are programmed in Fortran for future use as local basis functions in computational schemes. Numerics are required for the intermediate-$r$regime because the inner and outer asymptotic expansions do not extend far enough toward each other to enable rigorous asymptotic matching. The logarithmic correction terms explain why the leading far-field solution (used in the preliminary numerics) was insufficient even at very large distances.

Optimization of Reverse Osmosis Networks with Spiral-Wound Modules

An optimization of reverse osmosis (RO) networks for seawater desalination with spiral-wound modules (SWM) was presented in this work. The membrane transport model, which was based on the mass and momentum transport equations, took into consideration the longitudinal variation of the velocity, the pressure, and the salt concentration in the membrane modules. The pressure exchanger (PX) was included in the RO superstructure, and salinity increase caused by volumetric mixing in the PX was considered. The results obtained from the presented model were compared with the actual plant operational data from literature and found to be in good agreement with relative errors of 0.81%∼2.15% and 0.01%∼0.09%, in terms of water recovery and salt rejection, respectively. The optimum design problem was formulated as a mixed integer nonlinear programming (MINLP) problem. The variation of feed salinity was studied using the RO networks model. For the feed concentration higher than 32 kg/m3, one-stage RO system is favored. ...

A high-flux polyimide hollow fiber membrane to minimize footprint and energy penalty for CO2 recovery from flue gas

Using a process-guided approach, a new 6FDA-based polyimide — 6FDA–DAM:DABA(4:1) — has been developed in the form of hollow fiber membranes for CO2 recovery from post-combustion flue gas streams. Dense film studies on this polymer reveal a CO2 permeability of 224 Barrers at 40°C at a CO2 feed pressure of 10psia. The dense films exhibit an ideal CO2/N2 permselectivity of 20 at 40°C, which permits their use in a two-step counter-flow/sweep membrane process. Dry-jet, wet-quench, non-solvent-induced phase inversion spinning was used to create defect-free hollow fibers from 6FDA–DAM:DABA(4:1). Membranes with defect-free skin layers, approximately 415nm thick, were obtained with a pure CO2 permeance of 520GPU at 30°C and an ideal CO2/N2 permselectivity of 24. Mixed gas permeation and wet gas permeation are presented for the fibers. The CO2 permeance in the fibers was reduced by approximately a factor of 2 in feeds with 80% humidity. As a proof-of-concept path forward to increase CO2 flux, we incorporated microporous ZIF-8 fillers into 6FDA–DAM:DABA(4:1) dense films. Our 6FDA–DAM:DABA(4:1)/ZIF-8 dense film composites (20wt% ZIF-8) had a CO2 permeability of 550 Barrers and a CO2/N2 selectivity of 19 at 35°C. Good adhesion between the ZIF and the 6FDA–DAM:DABA(4:1) matrix was observed. CO2 capture costs of $27/ton of CO2 using the current, “non-optimized” membrane are estimated using a custom counterflow membrane model. Hollow fiber membrane modules were estimated to have order-of-magnitude reductions in system footprint relative to spiral-wound modules, thereby making them attractive in current space-constrained coal-fired power stations.

Desalination using membrane distillation: Flux enhancement by feed water deaeration on spiral-wound modules

Membrane distillation (MD) is considered a promising technology for desalination applications. In this paper, the main transport phenomena in membrane distillation are analyzed theoretically. One of the main limiting factors is the molecular diffusion resistance caused by stagnant air in the membrane pore volume. A great potential for flux enhancement has been identified to be the removal of air in the membrane pores. Preliminary experiments on water deaeration using a commercial membrane contactor were carried out. The dynamics of membrane and air gap deaeration using deaerated feed water were studied experimentally. A module test facility was equipped with a feed water deaeration setup. Full-scale spiral-wound modules with a membrane area of 5 and 10m2 have been used for comprehensive experimental studies on the use of deaerated feed water. The impact of deaeration at different pressures, feed flow rates, feed water salinities and temperature levels is quantified and discussed. A comparison of module operation with and without preceding feed water deaeration is given. The experimental results include module output rate, thermal energy demand, thermal efficiency and an estimation of the electrical energy demand. In all experiments, the beneficial effect of feed water deaeration can clearly be shown for total flux and thermal energy demand simultaneously. For selected operation points, the relative effect was identified to be more than 50% and the specific thermal energy demand dropped to values of less than 100kWhthm−3.

The thickness dependence of Matrimid films in water vapor permeation

Composite or asymmetric membranes with thin active layers are used in industrial spiral-wound and hollow fiber modules to maximize productivity. These thin active layers are more susceptible to plasticization and undergo physical aging more rapidly than thick films. In this work, the sorption and transport properties of poly(3,3′-4, 4′-benzophenone tetracarboxylic-dianhydride diaminophenylindane) (Matrimid® 5218) as membranes of thickness 1–58μm were studied with mixed gas/water vapor feed streams (CH4, CO2 and H2O) at 7.5bar and 35°C. The fractional free volume (FFV) of the films decreased significantly with decreasing film thickness for films below 10–15μm. Water vapor solubility was independent of thickness, but water permeability reduced by an order of magnitude as film thickness decreased. This loss in permeability was related to a decrease in the diffusion coefficient, which was in turn related to the loss of fractional free volume. The net effect of competitive sorption between water vapor and gas components and CO2 induced plasticization effect resulted in a reduction in both carbon dioxide and methane permeabilities and CO2/CH4 selectivities as vapor activity increased.

Comparison of nanofiltration membranes’ performance in flat sheet and spiral wound configurations: a scale-up study

ABSTRACT Nanofiltration (NF) membranes have been largely developed and commercialised over the past decade and are currently one of the most promising technologies for the separation of neutral and charged solutes in aqueous solutions. Sometimes NF is defined as a process between ultrafiltration and reverse osmosis; however, the separation mechanisms of this kind of membranes are not clear enough, and even today there are some questions remaining about how NF membranes work. Nowadays, there are many different types of NF membranes commercially available, so the first step before developing a new NF treatment plant is to know which one is going to be the most suitable membrane. There are two main configurations in which NF can be used: flat sheet and spiral wound module. The cross-flow module using flat sheet membranes is the simplest option to test an NF membrane but at the industrial scale, NF is basically used in the spiral wound configuration. Currently, there are no studies available regarding the difference of using both configurations. The objective of this work is to do an experimental study regarding the performance of two different NF membranes, NF270 (Dow Chemical) and ESNA 1-LF2 (Hydranautics), in two different scales, laboratory and pilot plant, using the most typical configurations in each case: flat sheet and spiral wound respectively. Using the same feed water, the operating conditions and the rejections of the membranes in both configurations will be studied in order to check if both operating scales can be comparable.

Evaluation of optimal reuse system for hydrofluoric acid wastewater

The treatment of hydrofluoric acid (HF) wastewater has been an important environmental issue in recent years due to the extensive use of hydrofluoric acid in the chemical and electronics industries, such as semiconductor manufacturers. Coagulation/precipitation and ion exchange technologies have been used to treat HF wastewater, but these conventional methods are ineffective in removing organics, salts, and fluorides, limiting its reuse for water quality and economic feasibility. One promising alternative is reverse osmosis (RO) after lime treatment. Based on pilot-scale experiment using real HF wastewater discharged from semiconductor facility, the spiral wound module equipped with polyamide membranes has shown excellent flux and chemical cleaning cycles. Our results suggest that coagulation/precipitation and spiral wound RO constitute the optimal combination to reuse HF wastewater.

Membrane filtration of chlorination and extraction stage bleach plant effluent in Indian paper Industry

The present study was carried out for the treatment of effluent from the chlorination and extraction stages of a bleach plant at an Indian pulp and paper mill. The effluents were taken from an integrated paper mill employing OCEOPHH sequence for the bleaching of hardwood pulp. Effluent was treated via ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). Thin film composite spiral-wound modules, having cross flow membranes composed of polysulfone and polyamide, were used in the study. Three initial inlet pressures were used for the UF and NF; 6.8, 10.3, and 13.7 bar. For RO initial inlet pressures of 10.3 bar, 13.7 bar and 17.2 bar, were taken in different trials. The retentate from each experiment was recycled back to the feed and retreated until the inlet pressure increased to the maximum cut-of pressure for each membrane. The UF permeate was fed to the NF, which was subsequently fed to the RO. Variations in the trans-membrane pressure and permeate flux were assessed. The removal of pollutants and fouling indices were obtained for each membrane at each initial inlet pressure.

Modeling spiral-wound membrane modules with applications for gas/vapor permeation

Gas/vapor permeation has become a common method for VOC (volatile organic compound) recovery and CO2 capture. The spiral-wound membrane module, which has high packing density, has been commonly used in gas/vapor permeation. In this study, the model that suits the spiral-wound PDMS (polydimethylsiloxane) membrane is obtained by using an integral transform from an N–S equation (Navier–Stokes) and a mass transfer differential equation. The predicted results indicate that the concentration polarization and spiral-wound membrane structure influence can be neglected. The mass transfer based on the MS–UNIQUAC (MS–U) model is also proposed and compared to that based on the Fick–Henry (F–H) model. The comparison results show that the mass transfer based on the F–H model can only be used in a gas mixture without condensable gas; the MS–U model should be used for a gas mixture that includes condensable gas. The influence of permeate flux and feed-side composition in the spiral-wound membrane at different operation conditions is also investigated using the MS–U model.

On the Design of a 4-End Spiral-Wound L/L Extraction Membrane Module

The present work describes the design and application of 4-end spiral-wound modules, mainly for extraction applications. Membrane spacers, a key part of spiral-wound modules, are tested for pressure drop, mass transfer, and mixing behavior. Further, different permeate channel designs are studied by means of a transport-limited surface reaction (copper dissolution method). The findings led to the design of a 4-end spiral-wound membrane module with reduced propensity to dead zones and maldistribution and finally to its application to the reactive extraction of phenol.

Comparative performance of flat sheet and spiral wound modules in the nanofiltration of reactive dye solution

Besides the opportunities for reuse, stringent regulations and growing public awareness demand an enhanced quality of effluent from dye industries. Treatment of an aqueous solution of dye (reactive red 198) was carried out in a nanofiltration unit using both flat sheet and spiral wound modules to obtain a comparative performance evaluation in terms of permeate flux and quality. Hydrophilized polyamide membrane with molecular weight cutoff of 150 was used for the experiments. Effects of trans-membrane pressure (TMP), feed concentration and addition of salt on permeate flux were investigated. Percent reduction of color, chemical oxygen demand (COD), total dissolved solid (TDS), and conductivity were determined to assess performance of the membrane. The maximum flux decline was 16.1% of its initial value at 490kPa TMP with 50ppm feed concentration in spiral wound module, whereas the same in flat sheet under same conditions was 7.2%. The effect of TMP showed a quasi-linear increase in flux with increasing pressure. Increased permeate concentration led to the reduction in observed retention of dye in the membrane. The average reduction in color, COD, and TDS were 96.88%, 97.38%, and 89.24%, respectively. The decline in permeate flux was more in case of spiral wound module compared to flat sheet. However, spiral wound module performed better in terms of color removal, COD reduction, and TDS removal. Substantial removal of color was achieved in the nanofiltration experiments with a marked reduction in COD and TDS. The process allowed the production of permeate stream with great reutilization possibilities.

Shear stresses and mass transfer at the base of a stirred filtration cell and corresponding conditions in narrow channels with spacers

This study aims to adequately characterize shear stresses and mass transfer coefficients at the membrane surface of a high pressure stirred filtration cell, and to determine equivalent conditions for flow in narrow channels with spacers. Employing electro-chemical techniques, measurements were made of local wall stresses and transfer coefficients, and of space-average mass transfer rates, at various Schmidt numbers and Reynolds numbers 6500–39,000. The local measurements revealed salient features of momentum and mass transfer at the cell base, and the average quantities were successfully correlated with the respective Reynolds numbers. Furthermore, from detailed numerical and experimental studies of cross-flow in narrow spacer-filled channels (simulating conditions in spiral-wound membrane modules), relevant data on wall shear stress and mass transfer were selected for comparison with the new results from the stirred-cell. This comparative data analysis allows estimation of the stirrer rotational speed ω which corresponds to equal area-average shear stress (or mass transfer coefficient) at the membrane surface of stirred cell and of spacer-filled channel (for specific cross flow velocity U). The range of ω values, corresponding to a certain U range, is different for the cases of matching mean shear stress or mass transfer rates in the two flow systems.

A mathematical study of the evolution of fouling and operating parameters throughout membrane sheets comprising spiral wound modules

Local experimental data on key process parameters, throughout membrane sheets of spiral-wound membrane (SWM) elements, are unavailable and very difficult to obtain; therefore, theoretical models are essential to better understand the evolution of fouling, which is helpful for improving design and operation of these modules. The mathematical model, formulated in a fundamental manner herein, takes into account the spatial flow field non-uniformities inside narrow channels with spacers (simulating SWM elements) and their interaction with the evolving deposits. A realistic meso-scale transient model, typical of the early stages of organic membrane fouling, is employed. Appropriate non-dimensionalization of model equations allows to treat separately the two (practically significant) cases of constant inlet pressure and constant average permeate flux. Several simplified cases are examined, for specific dimensionless parameter values, and asymptotic solutions are derived. The results of this analysis have guided the development of very efficient numerical techniques, most useful for future extensions towards the development of a comprehensive modeling tool, appropriate for module design calculations and for assessing detailed experimental data.

Fouling of Reverse Osmosis Membranes by Hydrocarbonated and Fluorinated Surfactants Contained in Firefighting Water

Large class B fires -- i.e. polar or non polar burning liquids -- can occur in places like refineries, airports or chemical plants. Such fires can be put out with the help of fire fighting foams prepared from specific aqueous formulations, called foam concentrates diluted in water to 1-6% and applied with a nozzle under the form of foam. Foam concentrates usually contain hydrocarbon surfactants or protein hydrolysates (synthetic or proteinic concentrate), and one or several fluorinated surfactants in case of high performance foam concentrates. During industrial solvent fires large amounts of water and foam are used: several cubic meters per minute during several days. Resulting water consists of either water from the foam and water used to protect equipment and persons from the heat of the fire. Therefore its composition is expected to be somehow close to diluted foaming solution. Surfactants are amphiphilic molecules able to lower interfacial tension. These compounds have the particularity to self-aggregate when their concentration reaches the critical micelle concentration. Fluorinated surfactants are a particular class of surfactants which can dramatically lower the water surface tension. This ability plays a key role in the efficiency of firefighting waters. In addition, fluorinated surfactants are highly resistant to thermal and chemical attacks. The current treatment for firefighting waters is therefore incineration in halogen resistant incinerators, which is not economically viable and not convenient on a logistical point of view. A previous paper aimed at proposing a process for purifying firefighting water containing fluorinated surfactants [1]. Experimental results indicated that electrocoagulation and filtration followed by reverse osmosis efficiently treated the water from fire extinguishment. In this work we focused on the reverse osmosis step. Polyamide and cellulose acetate membrane materials were screened in a flat sheet cell.with model solutions representative of synthetic fire fighting foams. The most appropriate membrane considering rejection was a smooth anti foulant thin film polyamide SG membrane, designed for brackish water. However, because of membrane fouling, there was a trade-off between high rejection and low flux decline. The SG membrane showed even better rejection properties in spiral-wound module with both real and model pretreated firefighting waters. Though the flux decline was high, it seemed to tend to an asymptote with the increasing concentration. The stabilities of rejection and flux decline were confirmed during longer tests on an industrial pilot with another fouling resistant thin film polyamide membrane for brackish water, a RE2540-FE membrane. The flux decline caused by the surfactant mixtures was found linked to adsorption. The flux decline seemed mainly due to the adsorption of the anionic surfactant which showed the highest adsorption density in concentrated solutions (figure 1). This surfactant also showed lowest rejection properties. However, selective removal of this compound for purpose of flux enhancement, if desired, should be carefully studied. Indeed, with little or no anionic surfactant in the solutions, there would be more free room for the hydrophobic adsorption of the other surfactants on the membrane, which could decrease their rejections. A model was proposed to describe the flux decline as function of the fluorinated surfactant concentration, somehow representing the global surfactant concentration. This model combined the resistance-in-series model to a Langmuir adsorption model by expressing the adsorption resistance as function of the retentate concentration (figure 2). Though this model would require to be tuned on the basis of extended experimental data, it adequately described the flux decline with retentate concentration of the model pretreated firefighting water. Further work could be done on the subject via membrane surface characterization, and study of mixed adsorption as well as mixed micellization of surfactant mixtures. In this work, solid data was gathered, such as the average rejection of the fluorinated surfactant in the industrial pilot which was 99.95%, and the permeability of the membrane of 0.5 L h m − 2 bar − 1 with model solution representing pretreated firefighting water concentrated by a factor 20. This could allow the calculation of the area required for the mobile unit.

REMOVED: Holographic Interferometry Visualization and CFD Simulation of the Concentration Boundary Layer Developed in NF Spiral–wound Modules Feed Channels

This article has been removed: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy ). This article has been removed at the request of the Executive Publisher. This article has been removed because it was published without the permission of the author(s).

Detection of free primary amines in TFC membranes by microscopic fluorescence imaging

A microscopic imaging method using the fluorescent binding agent, fluorescamine, has been applied to determine the presence and location of primary amines in the selective layer of TFC polyamide RO membranes. The presence of such amines is attributed to incomplete condensation reactions in the preparation of the membrane's active layer for fully aromatic TFC membranes. The concentration of free amines is greatest in the section of the active layer most distant from the external membrane surface. The free amines are effectively removed by combining rinsing with application of oxidation agents. As delivered in spiral wound modules they have already been removed to a large extent. In flat sheet membrane they still contain various extents of free amine depending on the membrane type and the supplier.

“Chemistry in a spinneret” to fabricate hollow fibers for organic solvent filtration

Organic solvent filtration (OSF) is a very efficient separation technique with high potential in many branches of industry. Currently the choice of the commercial membranes is limited only to a few flat sheet membranes and spiral wound modules. It is generally known that a membrane in hollow fiber form has several advantages, over a flat configuration, such as high surface to volume ratio and no need of spacers. Consequently more compact and simpler modules and easy to scale up can be built.In this work we explore a new technique called “chemistry in a spinneret”, to fabricate a hollow fiber (HF) for OSF. This technique combines the membrane formation and crosslinking reaction into a single step process. P84 polyimide was chosen as a membrane forming polymer and poly(ethylene imine) (PEI), dissolved in the bore liquid, as a crosslinking agent. In order to obtain a membrane with the best stability and low membrane MWCO, the composition of the bore liquid was systematically varied, including solvent/non-solvent ratio and PEI concentration.The crosslinked membranes have MWCO in the range of 2500–3500gmol−1 and toluene permeance in the range of 0.2–1.1lm−2h−1bar−1. The most stable crosslinked membrane maintains 80% of its mass after 11days immersion in N-methyl-2-pyrrolidinone. Due to crosslinking, the HFs become more hydrophilic and therefore attractive for separations in alcohol systems. Preliminary results are in fact presented here using an ethanol/polyethylene glycol model system.

Application of membranes to treat wastewater for its recycling and reuse: new considerations to reduce fouling and increase recovery up to 99 percent

The RO process is very attractive for providing high product quality through the removal of a number of contaminants like oil, detergents, organics, nitrates, ammonia, phosphates etc. However the main disadvantages of the modern RO techniques are connected with membrane fouling, concentrate flow and pretreatment that increase operational costs, complicate design and create problems of brine utilization. Often pretreatment costs even exceed reverse osmosis facilities costs. Now a number of successful attempts were undertaken to modify spiral wound membrane channels to limit fouling and scaling potential. As presented in a number of publications, elimination of the spacer mesh from the feed channels eliminates dead regions that provide scaling and fouling conditions whilst also reducing the risk of particle “trapping” and associated dramatic pressure increase. Introduction of a new “open channel” configuration offers a new perspectives to escape fouling and development of novel techniques to treat water with high fouling potential (high suspended matter, organics and supersaturated solutions). This novel concept of spiral wound module with an “open channel” design is developed, field-tested and introduced into practice. Fouling control is achieved due to the elimination of spacer and the implementation of an optimum hydraulic mode providing sufficient cross flow velocities, flushings and cleanings. The main principles of high recoveries, low maintenance and zero discharge are ensured by concentration of brine through re-circulation by 50−100 times by volume. Several examples of water treatment flow diagrams are presented to demonstrate of zero concentrate flow discharge. Coagulated suspended matter after membrane flushes is collected, sedimented and finally dewatered. The concentrated solution containing salts and impurities together with the wet sludge constitutes no more than 1 percent of initial water in part due to high supersaturation values due to the strong stability of calcium carbonate solutions.

CFD analysis of the initial stages of particle deposition in spiral-wound membrane modules

Particle deposition in a spiral-wound membrane module was simulated using computational fluid dynamics (CFD). A scheme similar to the Eulerian–Lagrangian numerical method was adopted for the two-phase flow simulation. The effect of curvature on particle transport in four spacer-filled channel configurations with permeable membrane surfaces was analyzed by considering the fluid drag, body force and lift force exerted on the particles. The numerical results showed that there are inherent changes in the particle deposition profile in the spacer-filled channel due to variations in curvature. Comparing the particle deposition profiles and deposition ratios for submerged, zigzag, i-cavity and o-cavity spacer-filled channels showed that, for a given feed velocity and permeation rate, the zigzag-type spacer is best at decreasing the influence of curvature and preventing particle fouling on the membrane. A microscopic understanding derived from the CFD analysis could improve module design and enhance membrane module performance.

Simultaneous anion and cation exchange chromatography of whey proteins using a customizable mixed matrix membrane

Membrane chromatography can overcome some of the limitations of packed bed column chromatography but preparation of adsorptive membranes usually involves complex and harsh chemical modifications. Mixed matrix membranes (MMMs) require only the physical incorporation of an ion exchange resin into the membrane polymer solution prior to membrane casting. An advantage of MMMs not previously exploited is that resins with differing adsorptive functionalities can be conveniently embedded within a single membrane at any desired ratio. This presents the opportunity to customize an adsorptive membrane to suit the expected protein profile of a raw feed stream e.g. bovine whey or serum. In this work, a novel mixed mode interaction MMM customized to extract all major proteins from bovine whey was synthesized in a single membrane by incorporating 42.5 wt% Lewatit MP500 anionic resin and 7.5 wt% SP Sepharose cationic resin into an ethylene vinyl alcohol base polymer casting solution. The mixed mode MMM developed was able to bind both basic and acidic proteins simultaneously from whey, with binding capacities of 7.16±2.24 mg α-lactalbumin g(-1) membrane, 11.40±0.73 mg lactoferrin (LF)g(-1) membrane, 59.21±9.90 mg β-lactoglobulin g(-1) membrane and 6.79±1.11 mg immunoglobulin Gg(-1) membrane (85 mg total protein g(-1) membrane) during batch fractionation of LF-spiked whey. A 1000 m(2) spiral-wound membrane module (200 L membrane volume, 1m(3) module volume) is predicted to be able to produce approximately 25 kg total whey protein per h.