Hollow Fiber Module Research Articles

Osmotically enhanced reverse osmosis using hollow fiber membranes

Osmotically enhanced reverse osmosis (OERO) effectively increases the water recovery in desalination as it can reduce the transmembrane osmotic pressure by a sweep solution. Utilizing a model based on mass-transfer principles, we report the performance of a hollow-fiber RO membrane module in OERO as a function of the operating conditions, the fiber geometry, and the membrane properties. The hollow fiber system allows the feed and sweep solutions to flow on both sides of the membrane. To avoid energy-intensive solute/water separation, fertilizer can be employed as a “green” sweep solution as it can be directly used for fertigation (fertilized irrigation). Simulations indicated that the water recovery is significantly enhanced by increasing the water permeance and decreasing the structure parameter of the hollow fiber membranes. Further, an investigation into the role of feed salinity suggests that longer fibers can provide a higher water recovery in the case of low-salinity water reuse, while larger-diameter fibers achieve a more efficient seawater desalination. A single-stage OERO process facilitates the enhancement of water recovery from 35.5 % and 14 % to 36.5 % and 34 % in the case of low-salinity and high-salinity desalinations, respectively. This study provides theoretical perspectives into the design of hollow fiber modules for OERO processes.

Carbon Dioxide Capture Using Sorbent-Loaded Hollow-Fiber Modules for Coal-Fired Power Plants

Abstract The impact of post-combustion carbon dioxide capture on the performance of a power plant is evaluated. A model of a coal power plant with post-combustion temperature swing adsorption (TSA) CO2 capture using sorbent-loaded hollow fibers is presented. The resulting performance and cost of carbon capture are compared with those of other adsorption-based technologies. A parametric analysis of the performance of the power plant with respect to key parameters in the hollow fiber module operation is presented. It is found that electrical energy consumption for the compression of CO2 is a major parasitic load (PL) common to all absorption technologies and accounts for almost half of the total parasitic load. The effect of source temperature, flue gas (FG) fan, and coupling fluid pump flowrates on overall system performance is presented. The impacts of different carbon capture technologies on the same coal-fired power plant are compared. Hollow fiber modules had the lowest parasitic load on the power plant, followed by KS-2 based carbon capture.

Evaluation of pretreatment and membrane configuration for pressure-retarded osmosis application to produced water from the petroleum industry

Pressure-retarded osmosis (PRO) is a promising membrane technology for harnessing the osmotic energy of saline solutions. PRO is typically considered with seawater/river water pairings however greater energy can be recovered from hypersaline solutions including produced water (PW) from the petroleum industry. One of the major challenges facing the utilization of hypersaline PW is its high fouling propensity on membranes. In this unique experimental evaluation, real PW from different sites was pretreated to varying degrees: i) minimal, ii) intermediate, and iii) extensive. The treated effluent was subsequently used for PRO testing and fouling rates were assessed for different membrane configurations over multiple cycles. Commercial grade flat sheet (FLS) coupons and novel hollow fiber (HF) modules were compared to validate the lower fouling propensity of HF membranes in PRO application. When minimally pretreated PW (10-micron cartridge filtration (CF)) was tested in FLS mode, severe membrane fouling occurred and the PRO flux decreased by 60%. In contrast, HF modules showed <1% flux decrease under both minimal and intermediate pretreatment schemes. Extensive pretreatment (1-micron CF, dissolved air flotation (DAF), powdered activated carbon, and microfiltration) reduced FLS PRO flux decline to <1%. These results confirm that PW can be treated to suitable levels for PRO application to avoid membrane fouling. Further validation of these pretreatment methods requires long term pilot testing and techno-economic assessment.

Performance Investigation of a Hollow Fiber Membrane-Based Desiccant Liquid Air Dehumidification System

The membrane-based desiccant liquid air dehumidification system is a promising technology for efficient humidity control in buildings. The use of a membrane module allows, among other things, for a compact design with a relatively large heat and mass transfer area and eliminates carryover of solution droplets. In this paper, a cross-flow, hollow-fiber membrane module was proposed for air dehumidification and regeneration of lithium chloride. A two-dimensional heat and mass transfer model for cross-flow in a membrane module used for air dehumidification and liquid desiccant regeneration was developed. The effectiveness, moisture removal rate and moisture removal rate were studied numerically and validated against experimental results. Based on the numerical simulations, the most favorable ranges of operating conditions were determined. It was found that the operating conditions significantly impact the dehumidification performance. The proposed dehumidifier maintains its performance in a wide range of inlet air humidity ratios. For dehumidification, the recommended temperature of the incoming solution was in the range of 14–18 °C, while for regeneration the solution range was 40–50 °C. The packing fraction was suggested in the range of 0.30–0.40. These results can help design membrane-based liquid dehumidification systems.

Repligen to acquire French membrane manufacturer Polymem

US life sciences company Repligen Corp has entered into an agreement to purchase Polymem SA, the French hollow fiber membranes and modules manufacturer.

Therapeutic Apheresis and Immunosuppression in Renal Diseases

Therapeutic plasma exchange (TPE) with hollow fiber modules is used in different severe diseases since more than 40 years. The authors try to give an overview of therapeutic apheresis (TA) in renal diseases. The updated information on immunology and molecular biology of different renal diseases are discussed in relation to the rationale for apheresis therapy and its place in combination with other modern treatments. The different renal diseases can be treated by various apheresis methods such as TPE with substitution solution, or with online plasma or blood purification using adsorption columns, which contain biological or non-biological agents. The following diseases are discussed: rapidly progressive glomerulonephritis (RPGN) including anti-glomerular basement membrane antibody glomerulonephritis (anti-GBM RPGN), RPGN with or without glomerular deposition (ANCA-ab), pauci-immune RPGN, immune complex nephritis (ICN), and various glomerulonephritis with nephrotic syndrome (NS), acute kidney injury (AKI), myoglobulinemic renal failure, hemolytic-uremic syndrome (HUS), and kidney transplant rejection. For the renal diseases, which can be treated with TA, the guidelines of the Apheresis Applications Committee (AAC) of the American Society for Apheresis (ASFA) are shown.

Forward osmosis system design and optimization using a commercial cellulose triacetate hollow fibre membrane module for energy efficient desalination

This study is aimed at developing system mathematical design models to simulate and optimize a full scale forward osmosis (FO) for a hollow fibre membrane module for energy efficient desalination. Experimental data from a commercial outer selective CTA hollow fibre FO membrane module was used for validation. Less than 10% difference between the simulation and experimental results were observed which validated the reliability of the models. Simulation and design were performed for a 1000 m3/day FO plant using 0.6 M NaCl as draw solution (DS) (~seawater) and 0.02 M NaCl feed solution (FS) (~MBR effluent) to produce 0.25, 0.2 and 0.15 M NaCl diluted seawater to reduce the energy consumption of downstream pressure driven desalination process. A single element parallel module arrangement was found more suitable for this commercial hollow fibre membrane element. Finally, the numerical simulations revealed that to achieve 0.25, 0.20 and 0.15 M final DS concentrations, the optimum number of modules required were 370, 435 and 555 respectively considering membrane cost and energy consumption. The FO system using the commercial CTA hollow fibre module was found more energy efficient than a commercial TFC spiral wound membrane module.

Theoretical and practical approach to the dealcoholization of water-ethanol mixtures and red wine by osmotic distillation

Osmotic distillation (OD) has been a subject of interest during the last few years due to its promising application in the production of low alcohol strength wines. This work focuses on the partial dealcoholization (-3 v/v%) of red wine (tempranillo) by OD, carrying out an experimental and theoretical process analysis. The dealcoholization process was performed using a polypropylene hollow fiber module at different experimental conditions whose influence in the ethanol behavior was evaluated. At the best tested conditions, the study of the behavior of ethanol and other five different alcohols (both aliphatic and aromatic) as a function of their volatility (Henry’s constant) and their interaction with the membrane (in terms of Hansen solubility parameters) validated the theoretical model proposed. As a result, a transport resistance expression that includes the alcohol-membrane interaction was successfully developed. This allowed to reduce the error between the experimental and theoretical alcohols concentrations in a relatively wide range of working conditions.

Full Scale Sanitary Landfill Leachate Treatment by MBR: Flat Sheet vs. Hollow Fiber Membrane

The aim of this study was to find a cost-efficient leachate treatment system by comparing two MBR systems, flat sheet and hollow fiber. Data collected through continuous monitoring and laboratory analysis over the last two years has been evaluated in terms of treatment performance and economic analysis. MBR systems were found to be as effective and economical in terms of color, SS removal, and total treatment efficiency. It has been observed that the flat sheet membranes were clogged up in six weeks, while the hollow fiber membranes took 12–16 weeks to clog. Moreover, the hollow fiber module was less clogged and needed shorter washing times, resulting in lower amounts of chemical consumption. Hollow fiber membrane systems, compared to flat sheet membrane systems, have higher operational availability and lower maintenance costs. For the first time, the advantage of using submerged hollow fiber for the treatment of high-strength landfill leachate has been clearly demonstrated.

Fully Polymeric Distillation Unit Based on Polypropylene Hollow Fibers

Access to pure water is a very topical issue today. Desalination represents a promising way of obtaining drinking water in areas of shortage. Currently, efforts are being made to replace the metal components of existing desalination units due to the high corrosivity of sea water. Another requirement is easy transportation and assembly. The presented solution combines two types of polymeric hollow fibers that are used to create the distillation unit. Porous polypropylene hollow fiber membranes have been used as an active surface for mass transfer in the distillation unit, while non-porous thermal polypropylene hollow fibers have been employed in the condenser. The large active area to volume ratio of the hollow fiber module improves the efficiency of both units. Hot water is pumped inside the membranes in the distillation unit. Evaporation is first observed at a temperature gradient of 10 °C. The water vapor flows through the tunnel to the condenser where cold water runs inside the fibers. The temperature gradient causes condensation of the vapor, and the condensate is collected. The article presents data for hot water at temperatures of 55, 60, and 65 °C. Optimization of the membrane module is evaluated and presented.

Mathematical modeling and numerical simulation of CO2 capture using MDEA-based nanofluids in nanostructure membranes

The current paper reports a numerical simulation as well as mechanistic modeling of gas separation using nanostructured polymeric membranes. To improve the process separation efficiency, nanoparticles of CNT (carbon nanotube) were incorporated into the solvent to prepare a nanofluid solvent for CO2 capture from a CO2+N2 gas mixture. The membrane used was a hollow-fiber module in counter-current separation operation to enhance the removal efficiency. A mechanistic model based on mass transfer was developed and validated through experimental measured data, and a good agreement was obtained. Computational fluid dynamic approach was used for solving the model’s equations and for simulating the process. It was indicated that the addition of nanoparticles to the solvent increases the CO2 separation percentage due to the synergistic effect of nanoparticles. The simulation results revealed that the gas separation efficiency was improved by increasing the solvent concentration, solvent velocity in the module, and membrane porosity. On the other hand, increasing the gas velocity indicated negative influence on the removal efficiency of CO2 using the nanofluid. The results indicated that nanofluid-based membrane gas separation is a promising approach for process intensification for environmental applications.

Comparison of Pressure-Retarded Osmosis Performance between Pilot-Scale Cellulose Triacetate Hollow-fiber and Polyamide Spiral-Wound Membrane Modules.

Pressure-retarded osmosis (PRO) has recently received attention because of its ability to generate power via an osmotic pressure gradient between two solutions with different salinities: high- and low-salinity water sources. In this study, PRO performance, using the two pilot-scale PRO membrane modules with different configurations—five-inch cellulose triacetate hollow-fiber membrane module (CTA-HF) and eight-inch polyamide spiral-wound membrane modules (PA-SW)—was evaluated by changing the draw solution (DS) concentration, applied hydrostatic pressure difference, and the flow rates of DS and feed solution (FS), to obtain the optimum operating conditions in PRO configuration. The maximum power density per unit membrane area of PA-SW at 0.6 M NaCl was 1.40 W/m2 and 2.03-fold higher than that of CTA-HF, due to the higher water permeability coefficient of PA-SW. In contrast, the maximum power density per unit volume of CTA-SW at 0.6 M NaCl was 4.67 kW/m3 and 6.87-fold higher than that of PA-SW. The value of CTA-HF increased to 13.61 kW/m3 at 1.2 M NaCl and was 12.0-fold higher than that of PA-SW because of the higher packing density of CTA-HF.

Optimization of interfacial polymerization to fabricate thin-film composite hollow fiber membranes in modules for brackish water reverse osmosis

The development of commercial-scale thin-film composite (TFC) hollow fiber membranes and modules for reverse osmosis (RO) has been lagging behind spiral wound TFC flat-sheet membranes and modules for many years. The delay arises from the challenges of synthesizing a defect-free polyamide selective layer on hollow fibers in modules. In order to solve this problem, a novel interfacial polymerization method is presented in this work to fabricate 1-inch TFC hollow fiber membrane modules for RO applications. By circulating the m-phenylenediamine (MPD) solution on the lumen side under a positive pressure and circulating the trimesoyl chloride (TMC) solution at the atmosphere pressure, a strong, uniform and defect-free polyamide selective layer is formed on the inner surface of hollow fiber membranes in modules. Under pressure, not only MPD monomers are evenly distributed on the inner surface of each hollow fiber substrate in modules, but also sufficient MPD monomers can retain in the substrate pores for further reaction with TMC monomers. The best RO performance obtained by this newly developed TFC hollow fiber membrane module has a water permeability of 4.49 L m−2 h−1 bar−1 and a NaCl rejection of ~99%, using a feed solution of 1000 ppm NaCl under a transmembrane pressure of 20 bar. The novel interfacial polymerization method may provide useful insights to fabricate TFC hollow fiber membrane modules for desalination of brackish water.

Performance of a Micro-Scale Membrane Reactor for Greywater Treatment at Household Level.

An aerated membrane reactor (25 L working volume) equipped with 1.5 m2 hollow-fiber module was designed and operated using synthetic greywater for household water reuse. Activated sludge (MBR), activated carbon (PAC), zeolite (ZEO) and iron hydroxide (GEH) were added in separate experiments to optimize membrane hydraulic performance and removal efficiency of organics. The use of additives improved permeate quality (in terms of Chemical Oxygen Demand—COD) compared to the direct membrane filtration mode of operation. GEH and MBR were efficient for phosphorus removal, which was not the case for PAC and ZEO. No significant improvement of membrane flux was recorded when PAC, ZEO or GEH were added inside the membrane tank. The MBR system displayed optimum performance during medium-term operation, with COD removal efficiency 85% and permeate flux between 40 and 25 L m−2 h−1. The capital costs of the proposed technology were around 300 € and the operational costs below 80 € yr−1, rendering the process feasible at household level. Greywater treatment systems for household applications are still on their infancy; however, this trend is expected to change due public perception towards circular economy, water conservation and reuse.

Study of the rejection of contaminants of emerging concern by a biomimetic aquaporin hollow fiber forward osmosis membrane

Forward osmosis (FO) plays an increasingly important role in membrane processes because of its advantages compared to traditional pressure-driven membrane processes. There are different types of water-selective FO membranes. In this study, a biomimetic hollow fiber module comprising an active layer of polyamide thin film composite (TFC) with integrated aquaporin proteins and an effective area of 0.6 m2 is used to study the rejection of 24 Contaminants of Emerging Concern (CECs). The rejections obtained for all the contaminants studied were higher than 93 % and for 19 of them rejections of up to 99 % were reached. It was observed that although all the tested compounds showed rejections very close to 100 %, they were not completely recovered in the feed solution which makes the retention within the membrane an important factor to be considered. Hence, two membrane rinses were necessary after each membrane operation to completely recover each contaminant. The results were analyzed considering the physicochemical properties (molecular weight, charge and hydrophobicity) of the contaminants.

Advanced Application and Fouling Control in Hollow Fibre Direct Contact Membrane Distillation (HF-DCMD)

In this article, the most advanced applications and the major operating problems of hollow fibre direct contact membrane distillation (HF-DCMD) are discussed. Over the past few years, direct contact membrane distillation (DCMD) became one of the most preferred technology not only for high-saline desalination process, but also for the water treatment process. The fundamentals of the DCMD and governing equations (from heat and mass transfer principles) that describe performance parameters are first explained. To increase the desalination performance of DCMD technology, some of the DCMD models were upgraded with the hollow fibre module. The efficiency of the HF-DCMD is explained further in this review. Major problems in the HF-DCMD technologies especially on membrane fouling and operating conditions are also discussed in this article. However, it is expected that HF-DCMD offers promising prospects in the future and potential outlook for better performance.

A fast and scalable mesh generation method of densely packed hollow fibers for membrane separations: Application to direct contact membrane distillation

Modeling research on membrane distillation requires simulations of coupled momentum, mass, and heat transfer phenomena. Hollow fiber modules are preferred in industrial applications due to their high packing ratio, resulting in the number of fibers on the order of O(102−103) packed in a vessel. In hollow fiber membrane distillation processes, computational fluid dynamics (CFD) simulations of multi-physics require high-quality meshes for accurate calculations. Mesh interfaces between two different phase regions should conform to satisfy continuity conditions of coupled momentum, heat, and mass transfer. Due to the distinct geometric characteristics of HF packing structures, a scalable meshing method is of great necessity but has not been actively researched. This work developed a numerical method to generate hexagonally packed structures of many fibers by forming a hexagonal unit-cell, consisting of the lumen, membrane, and shell regions. Individual cells are made by duplicating a seed cell and packed to create a self-similar, hexagonal packing of hollow fiber membranes for multi-physics CFD simulations. A new theoretical approach was developed to represent the effusion-like convective mass transfer as conductive heat transfer, and our CFD results were in good agreement with experimental observations. Theoretical methods and numerical algorithms developed in this study can contribute to the improved scalability of CFD simulations from lab-scale modules to pilot-scale systems.

Removal of Methyl Green Dye from simulated waste water using Hollow Fiber Ultrafiltration Membrane

Ultrafiltration has been favorably employed for recycling insoluble dyes and high molecular weight, some type of chemicals and water. Despite, ultrafiltration does not remove low molecular weight and soluble dyes (acid, direct, reactive, basic, etc.). The main advantages of the hollow fiber module are very high packing density and low-energy consumption. In this investigation, the performance of a Polyvinyl chloride (18 wt % PVC) hollow fiber ultrafiltration (UF) membrane for methyl green (MG) dye removal from aqueous solution was evaluated by examining the impact of varying the operation conditions (the concentration of dye and volumetric flow rate) to determine their impact on the separation processes (permeate flux and rejection coefficient) at constant pressure, temperature and at neutral pH. two configurations used: Semi-batch filtration and continuous filtration. UF was characterized by scanning electron microscopy. Besides, tests of the UF were carried out with pure water and MG aqueous solutions as feed. Results exhibited a notable influence of flow rate and feed concentration on the permeate flux and rejection, where the highest flux obtained equal to 32.7 l/hr.m2 with the highest rejection coefficient value close to 59.46% of the membrane system.

Field trial of hollow fiber modules of hybrid facilitated transport membranes for flue gas CO2 capture in cement industry

Alarming increase in global CO2 emissions warrants acceleration of CO2 capture technologies. In this work, testing of pre-pilot scale membrane modules containing hybrid facilitated transport membranes in hollow fiber configuration is reported. The tests were carried out using real flue gas from a slipstream in the Colacem cement plant located in Gubbio, Italy. With the fabricated modules, CO2 flux of up to 750 NL m−2h−1 with a CO2 permeate purity ranging from 50 to 55 vol% was recorded. All pre-pilot membrane modules showed increased CO2 permeance in industrial testing (1.5 to 1.9x higher) compared to laboratory evaluation owing to the reliable water profile and high temperature of the flue gas from the chimney. Influence of operating parameters (e.g., pressures in the feed and permeate) were studied. Long-term testing showed no obvious reduction in permeation performance. Furthermore, the membranes with mobile carriers when exposed to the feed gas containing SOx and NOx exhibited good resistance to performance deterioration despite high concentrations of acidic impurities. Simulation studies based on validated experimental performance under industrial conditions reveal the high potential of the fabricated membranes as an efficient separation unit capable of achieving industrial capture rate and CO2 purity requirements using a relatively low membrane area.

Enhanced filtration performance using feed-and-bleed configuration for purification of antibody precipitates.

Precipitation can be used for the initial purification of monoclonal antibodies (mAbs), with the soluble host cell proteins removed in the permeate by tangential flow microfiltration. The objective of this study was to examine the use of a feed-and-bleed configuration to increase the effective conversion (ratio of permeate to feed flow rates) in the hollow fiber module to enable more effective washing of the precipitate. Experiments were performed using human serum Immunoglobulin G (IgG) precipitates formed with 10 mM zinc chloride and 7 wt% polyethylene glycol. The critical flux was evaluated as a function of the shear rate and IgG concentration, with the resulting correlation used to predict conditions that can achieve 90% conversion in a single pass with minimal fouling. Experimental data for both the start-up and steady-state performance are in good agreement with model calculations. These results were used to analyze the performance of an enhanced continuous precipitation-microfiltration process using the feed-and-bleed configuration for the initial capture / purification of a mAb product.