PATENTS

12Membrane Technology July 2012

PATENTSFluid-flow distribution device

Applicant: Siemens Industry Inc, USAEmbodiments of this invention relate to an improved apparatus for flowing fluid to or from a membrane module. According to the patent, the approach described overcomes, or at least ameliorates, one or more of the disadvantages associated with previous systems or at least pro-vides a useful alternative.Patent number: WO/2011/136888Inventors: B.G. Biltoft, J.T. Law, Z. Cao and H.A. LazaredesPublication date: 3 November 2011

Micro-sieve for cell and particle filtration

Applicant: Agency for Science, Technology and Research, SingaporeThis patent provides details of a micro-sieve that is composed of two layers. The first layer – which has a thickness of about 10 μm to about 100 μm – is a membrane layer contain-ing a plurality of micro-pores. The second layer – which has a thickness of about 100 μm to about 500 μm – is a membrane support layer that contains a plurality of openings. The diam-eter of these openings is larger than that of the micro-pores.Patent number: WO/2011/139233Inventors: M.-H. Li, M. Hu, Min,

W.C. Cheong and T.L. GanPublication date: 10 November 2011

Electron source modification of microporous halocarbon filter membranesApplicant: Entegris Inc, USAVersions of this invention include electron-beam treated microporous halocarbon mem-branes, particularly fluorocarbon membranes, and methods for treating one or more surfaces of a polymeric porous halocarbon membrane with electron beams. The modified porous membrane is stable, resists de-wetting, and retains its mechanical properties and chemical inertness.Patent number: WO/2011/139656Inventors: J. Ge and W.M. ChoiPublication date: 10 November 2011

Polymer-coated hydrolysed UF membrane

Applicant:/Inventor: J. Herron, USAThis patent describes a method of forming a polymer-coated hydrolysed membrane. It involves forming a membrane from a first hydrophilic polymer by immersion precipita-tion, coating the membrane with a thin layer of a second hydrophilic polymer (which is more pH tolerant than the first hydrophilic polymer) to form a dense rejection layer, and exposing the coated membrane to a high pH solution, thereby forming a hydrolysed ultrafiltration (UF) membrane.

Patent number: WO/2011/140158Publication date: 10 November 2011

Method for removing contaminants from natural gas

Applicant: Linde Aktiengesellschaft, GermanyA method for removing contaminants from natural gas streams has been developed. The natural gas stream is fed to a dryer, then to a membrane module and a multi-bed, multi-layer vacuum swing adsorption process which removes oxygen, nitrogen and carbon dioxide. The membrane module step is not employed when carbon dioxide is present in a relatively low concentration in the natural gas stream.Patent number: WO/2011/139500Inventors: R.H. Sethna and R. KrishnamurthyPublication date: 10 November 2011

Apparatus for dosing flux-enhancing chemicals

Applicant: General Electric Co, USAIn this patent, a membrane bioreactor (MBR) uses a process and apparatus for dosing flux-enhancing chemicals (FECs) in order to respond to temporary periods of operation that cause, or are likely to cause, membrane foul-ing. An FEC dosing device is connected to a channel that separates a process tank and the membrane filtration system contained in the MBR. A mixer in the channel rapidly mixes dosed FECs with mixed liquor flowing into the membrane tank. The dosing device is also con-nected to sensors which determine the condi-tions in the channel or the membrane filtration system, or both. The amount of FECs added to the mixed liquor flowing into the membrane filtration system depends on specific conditions or membrane operating parameters, or both. The FEC dosage may range from 0.05 mg/g to 10 mg/g mixed liquor suspended solids. The process may also include steps of initiating and terminating dosing, and adjusting the dosing concentration.Patent number: WO/2011/137557Inventors: S. Chang, S. Wang, B.F. Ginzburg and F. FanPublication date: 10 November 2011

Nanofiltration membrane

Applicant: National University of Singapore, SingaporeThe nanofiltration (NF) membrane detailed by this patent includes a supporting fabric layer (1); an engineered nano-fibrous structural layer (2), deposited on the supporting fabric layer;

Patent WO/2011/139233 provides details of a two-layer micro-sieve. The figure above shows a scanning electron microscope image of the micro-sieve structure (a); a cross-section of a 10-μm diameter through the channels (b); and optical images of highly uniform 10-μm and 25-μm diameter SU-8 micro-sieves (c & d).

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July 2012 Membrane Technology13

and a polyamide thin-film (3) deposited on the engineered nano-fibrous structural layer. The supporting fabric layer is 100–200 μm thick, the engineered nano-fibrous structural layer is 30–75 μm thick and contains pores measuring 0.4–1.5 μm, and the polyamide thin-film is 100–300 nm thick. Also disclosed is a method of preparing this NF membrane.Patent number: WO/2011/142726Inventors: R.S. Barhate, S. Ramakrishna and B. RamalingPublication date: 17 November 2011

Oil-tolerant polymer membranes for oil–water separationApplicant: The Regents of the University of California, USAThis invention relates to oil-tolerant water-filtration membranes that can be used to sepa-rate hydrocarbons and hydrocarbon emulsions from a water sample. These materials consist of a microporous hydrogel coated on a porous polymeric support membrane. The hydrophilic microporous cross-linked polymeric hydrogel is applied to at least one side of the porous poly-meric support material. The membrane has a first face, corresponding to the discrimination layer, and a second face corresponding to the porous support. A water solution, containing at least one solute, is applied under pressure to the first face of the membrane, while purified water is collected at its second face. According to the inventors, polymeric membranes have many advantages over ceramic materials – they are relatively inexpensive to manufacture and also can be used to make compact elements with a high surface area.Patent number: WO/2011/143371Inventors: E.M. Hoek, F. Peng and J. WangPublication date: 17 November 2011

Reaction vessel for a PCR device

Applicant: Curetis Ag, GermanyThis patent provides details of a reaction ves-sel (20) for a polymerase chain reaction (PCR) device. The reaction vessel comprises a sample vial (32), defining a reaction chamber (33) for performing PCR, and a vessel (62) defining a storage chamber for optical detection. The reac-tion chamber (33) is connected to a port (34)

for supplying a liquid sample – containing at least one target DNA – to the reaction chamber (33). The reaction chamber (33) and the storage chamber are in contact via a spacer element (42) and a porous membrane (51), for the hybridisa-tion of at least one target DNA, within the liq-uid sample, onto specific immobilised hybridisa-tion probes. The lower end of the spacer element (42) extends into the reaction chamber (33), but does not reach the bottom of it. The upper end of the spacer element (42) is located close to the porous membrane (51), which is made from a material having different physical properties in a dry state and a wet state. In the dry state the porous membrane (51) allows air and liquid to pass through its structure. In the wet state it still allows the passage of liquid, but not air, such that during a PCR the liquid sample remains in the reaction chamber (33). After the PCR, the reaction vessel is configured to force the liquid sample via the spacer element (42) to the porous membrane (51) for hybridisation and detection of the target DNA. A PCR device composed of such a reaction vessel and the method for per-forming PCR are also described.Patent number: WO/2011/144345Inventors: G. Lüdke, A. Boos, H. Motejadded and J. BacherPublication date: 24 November 2011

Organophilic polysilsesquioxane membranes for solvent nanofiltration and pervaporation

Applicant: Stichting Energieonderzoek Centrum Nederland, The NetherlandsThis invention relates to microporous organo-philic organic–inorganic hybrid membranes suit-able for liquid or vapour separation applications and to a process for producing them. The selec-tive retention of a relatively hydrophilic molecule from a mixture of a relatively hydrophobic molecules and relatively hydrophilic molecules

is achieved using a hydrophobic, microporous hybrid membrane based on silica, in which at least 25% of the silicon atoms are bound to a bridging C1-C12-hydrocarbylene group. The average number of carbon atoms of the bridging groups and any additional monovalent organic groups, taken together, is at least 3.5. This mem-brane can be used in part of a production facility for separating alcohol/water mixtures.Patent number: WO/2011/145933Inventors: R. Kreiter, G.G. Paradis, J.F. Vente, H.L. Castricum and J.E. Ten ElshofPublication date: 24 November 2011

Pressure vessel for SWRO and a process that avoids scaling problemsApplicant: General Electric Co, USAIn this invention a sea-water reverse osmosis (SWRO) module for use in a desalination plant receives refresh water to increase production and product quality, and reduce scaling prob-lems. The module includes a pressure vessel that has a front-end feed port, a rear-end brine port and a rear-end permeate port. A plural-ity of RO membrane elements are located in series within the pressure vessel. At least one refresh port – leading to an interconnector mix-ing zone within the pressure vessel – is located between two of the plurality of RO membrane elements. The port is configured in such a way that refresh water added to the SWRO module, through the refresh port, mixes with the feed water supplied through the front-end feed port in the interconnector mixing zone.Patent number: WO/2011/149626Inventor: O.J. Viera CurbeloPublication date: 1 December 2011

Device for filtering catalytic cracking slurry oil

Applicant: Beijing Zhong Tian Yuan Environmental Engineering Ltd, ChinaA device and method for filtering catalytic crack-ing slurry oil forms the subject of this patent. The device comprises a slurry-oil circulating tank (1), a cross-flow membrane filter (2) and a circu-lating pump (7). The filter includes a core struc-ture and a housing. The core is located inside the housing, and a space exists between the outer surface of the filter core and the side-wall of the housing. The side-wall of the housing is provid-ed with a first opening. The slurry-oil circulating tank (1) is connected to the lower end of the filter core of the cross-flow membrane filter via the slurry-oil circulating pump. This opening is connected to pipework (5) for discharging slurry

An illustration of the cross-section of the nanofiltration membrane described by patent WO/2011/142726, showing the three layers.

Patent WO/2011/144345 provides details of a vessel for a polymerase chain reaction (PCR) device. It includes a porous membrane (51) for the hybridisation of at least one target DNA, within a liquid sample, onto specific immobi-lised hybridisation probes.

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14Membrane Technology July 2012

oil that has been cleaned. Circulating slurry-oil pipework (15) is connected between the upper end of the filter core and the circulating tank. The method of filtration described involves providing a catalytic cracking slurry oil feed; channelling this feed through the filter core of the cross-flow membrane filter, thereby separat-ing the catalytic cracking slurry oil feed into clean slurry oil and a concentrated slurry oil; and discharging the cleaned slurry oil via the opening and pipework (5).Patent number: WO/2011/147173Inventors: Z. Xie, B. Cao, D. Huang, S. Cao and Q. ChenPublication date: 1 December 2011

Reinforced electrolyte membraneApplicant: 3M Innovative Properties Co, USAThis patent describes an electrolyte membrane that contains a proton-conducting polymer, rein-forced with a nano-fibre mat made from a fibre material selected from polymers and polymer blends. In some embodiments the nano-fibre is composed of a proton-conducting polymer.Patent number: WO/2011/149732Inventors: M.A. Yandrasits, J-H. Lee, Y. Yi, D.M. Pierpont, S.J. Hamrock and M.A SchonewillPublication date: 1 December 2011

Cordierite membrane

Applicant: Corning Inc, USAThis invention relates to methods of making cordierite monolith substrates with cordier-ite membranes for the separation of fluids. Embodiments of this patent describe cordierite membrane monolith substrates with a pore size of less than 1 μm. These substrates are preferred for certain applications, including those which require the use of a polymer membrane on a monolith substrate. Other uses include applica-tions that rely on a polymer membrane on a monolith substrate that is capable of holding a vacuum across the monolith structure; a small pore size; and a smooth surface, free of cracks.Patent number: WO/2011/149744Inventors: J.E. Clinton, K.J. Drury,

Y. Gu and M.E. SaundersPublication date: 1 December 2011

Coated polyamide membrane

Applicant: Dow Global Technologies Llc, USAThis patent covers the production and applica-tion of a composite membrane that uses a coat-ing of polyalkylene oxide and oxy-substituted phenyl compounds. In one embodiment the membrane described consists of a thin-film polyamide layer, including a coating of a reac-tion product of a polyalkylene oxide compound and an oxy-substituted phenyl compound. In another embodiment, the coating is composed of a polymer, including alkylene oxide repeating units and one or more oxy-substituted phenyl functional groups.Patent number: WO/2011/149573Inventors: W. Mickols and C. ZhangPublication date: 1 December 2011

Composite membrane containing ‘‘through-thickness’’ micro-pores

Applicant: Chung-Ang University Industry-Academy Cooperation Foundation, KoreaThis invention relates to a polymer, or polymer composite, membrane that contains ‘‘through-thickness’’ micro-pores, and a method of preparing it. In particular, it covers a polymer or polymer composite membrane which has a structure containing micro-pores that are arranged in the form of a mesh, in the thick-ness direction of the polymer, or polymer com-posite, membrane, because of unidirectional freezing in the thickness direction of a solvent. The structure described has improved penetra-tion in the direction of the thickness and supe-rior uniformity in the size of the micro-pores and thickness of the walls between the micro-pores, and thus can be used as a porous sub-strate in applications such as membrane-based microfiltration.Patent number: WO/2011/149165Inventors: J.H. Lee and M.K. LeePublication date: 1 December 2011

Filtration membrane module

Applicant: Meidensha Corp, JapanDetails of a filtration membrane module are provided. It has flat plate-like headers to which at least one end-side of each filtration mem-brane is affixed. Covers, formed in a housing-like shape, have openings which are closed by the headers to form chambers for collecting water that has passed through the filtration membranes. Each cover is provided with a

water conveyance path chamber that bridges and connects the upper and the lower plates of the cover. A water collection opening is formed in part of the water conveyance path chamber. Discharge openings, formed in connection sec-tions of the water conveyance path chamber, are located in the upper and lower plates of the cover. Filtration membrane modules that have such a configuration have sufficient strength to be easily and inexpensively stacked in tiers.Patent number: WO/2011/148768Inventors: T. Ugajin and H. ShiraishiPublication date: 1 December 2011

Hollow-fibre membrane module

Applicants: Hydranautics and Mitsubishi Rayon America Inc – USAThis patent describes a hollow-fibre membrane module that has a simple structure throughout which air is dispersed. The module includes a membrane bundle that consists of a plurality of hollow fibres. It also includes an upper potting section and a lower potting section in which the ends of the hollow-fibre membrane bundle are secured using resin. This is done in such a way that the hollow-fibre membranes’ ends are open. Diffuser pipes are arranged on the upper surface of the lower potting section and extend radially in three or more directions.Patent number: WO/2011/150206Inventor: M. SasakawaPublication date: 1 December 2011

A cross-sectional view of one embodiment of the membrane module that is described by patent WO/2011/150206. The module (10) casing contains a hollow-fibre membrane bundle (14) in which multiple membranes (12) are vertically oriented.

A device and method for filtering catalytic cracking slurry oil forms the subject of patent WO/2011/147173.

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July 2012 Membrane Technology15

System for monitoring permeate quality in water treatment facilities

Applicants: Saudi Arabian Oil Co and Aramco Service Co – USAThis invention covers a method and apparatus for continuously monitoring permeate from membrane elements in a water treatment plant, including a desalination facility. The apparatus includes a probe that includes multiple sen-sors. At least one sensor is associated with each membrane element. Each sensor is coupled to a node, which is configured to communicate a signal associated with the permeate quality to a central node sink. The node may communicate wirelessly with the node sink.Patent number: WO/2011/149761Inventors: A.J. Karabelas, I. Gragopoulos and N.P. IsaiasPublication date: 1 December 2011

Method for designing a filtration system

Applicant: California Institute of Technology, USAThis patent provides details of a method for designing a filtration system for efficiently cap-turing viable tumour cells – such as circulating tumour cells. The method involves developing a set of ‘‘key engineering design parameters’’ that are crucial to achieve high tumour cell viability. These important parameters include the filter geometry design, fluid delivery method, trans-filter pressure and total filtration time.Patent number: WO/2011/150357Inventors: Y.-C. Tai and B. LuPublication date: 1 December 2011

Membrane for blood filtrationApplicant: DSM IP Assets BV, The NetherlandsA membrane structure that consists of multiple layers forms the subject of this patent. At least one of the layers is a nano-web made from poly-meric nano-fibres. The mean flow pore-size of the nano-web is 50 nm to 5 μm and the average diameter of the nano-fibres is 100–600 nm. The basis weight of the nano-web is 1–20 g/m2 and its porosity is 60–95%. At least one of the layers

is a support layer. The nano-web is hydrophilic.Patent number: WO/2011/151314Inventors: K. Dullaert, M. Dorschu, J. Qiu and J.C. ThiesPublication date: 8 December 2011

Forward osmosis device and method

Applicant: Fujifilm Corp, JapanDisclosed is a forward osmosis (FO) device. The concentration polarisation of the FO membrane contained in the device is mini-mised. The FO device uses a semi-permeable membrane supported by a mesh, and is characterised by specific parameters defined as Z 0.09 × X/Y, X 1000 and Y 500, (where X represents the thickness (nm) of the semi-permeable membrane, Y the gap diam-eter (μm) of the mesh and Z the inter-mem-brane pressure (MPa) of the FO membrane.Patent number: WO/2011/155338Inventor: H. IsobePublication date: 15 December 2011

Fluorescence-based fouling forecasting to optimise membrane filtration operationsApplicants:/Inventors: R.H. Peiris, H.M. Budman, C. Moresoli and R.L. Legge – CanadaA fluorescence-based modelling method has been developed that is capable of capturing the dynamic changes of different membrane foulant fractions which occur in fluid filtration opera-tions. According to the inventors, principal com-ponent analysis (PCA) is used to ‘‘de-convolute’’ spectral information, captured within fluores-cence excitation-emission matrices (EEMs), into principal component scores that are related to different known foulant groups. These scores are then used as states within a system of dif-ferential equations – representing approximate mass balances of the main foulant groups – to obtain a dynamic forecasting of membrane foul-ing. Based on the fouling dynamics forecasted by this modelling method, an optimisation strategy can be developed for estimating the optimal membrane back-washing scenario for minimis-ing energy consumption, while maximising clean fluid production. The graphs in the accompany-ing figure demonstrate the model forecasts of

the fouling behaviour for ultrafiltration (UF). The graphs demonstrate the model forecasts of fouling behaviour for UF of source water (pre-filtered) using 60 kDa (60) and 20 kDa membranes (62), with back-washing performed at regular time intervals of 1 hour (that is, before implementing optimal back-washing intervals). When back-washing times were optimised (using the approach described) for the 60-kDa membrane, the model forecasts indicated energy savings of 3.7%, with a 4.3% increase in the total volume of drinking water production. The back-washing times generated by the optimisa-tion approach were: t1 = 61 min, t2 = 90 min, t3 = 118 min, and t4 = 137 min. Applying the same approach to the 20-kDa membrane, it was possible to achieve energy savings of 2.6%, with a 3.1% increase in the total volume of water production. The corresponding optimum back-washing times for the 20-kDa membrane were: t1 = 69 min, t2 = 97 min, t3 = 132 min and t4 = 172 min. The optimal back-washing cycles were implemented experimentally in order to test the validity of the optimisation results.Patent number: WO/2011/153625Publication date: 15 December 2011

A fluorescence-based modelling method (detailed by patent WO/2011/153625) has been developed that is capable of capturing the dynamic changes of different membrane foulant fractions which occur in fluid filtration.