FIELD OF THE INVENTION

[0001] The present application provides a unique hollow fiber (HF) or tubular semipermeable membrane element (hereafter "HF membrane element"), apparati comprising the HF membrane element, and methods for using the HF membrane element and apparatus.

Background

[0002] Osmosis has been used to treat industrial wastewaters, to concentrate landfill leachate, and to treat liquid foods in the food industry with low salinity content. Recent developments in material science also have allowed the use of osmosis in controlled drug release and in dialysis.

[0003] Compared to other industrial separation processes, osmosis has the advantage of operating at low to no hydraulic pressure; rejecting a wide range of contaminants; possibly having a lower membrane fouling propensity; and, using relatively simple, basic equipment.

[0004] Attempts have been made to use osmosis to generate power, but with limited success. One problem lies in the design of conventional semipermeable membrane elements, known commercially as modules or vessels. Currently available semipermeable membrane elements comprise tubular cylinders with relatively small bores, typically around 200 mm (8 inches) or less. A typical length of the currently available semipermeable membrane elements is only from about 1000-1500 mm.

[0005] Larger scale osmosis plants than those currently in existence, such as large scale power generation plants, would handle massive quantities of brine and produce large in-situ changes in flow rate within plant cells. Conventional osmosis hollow fiber or spiral wound membrane modules might be suitable for very small power generation applications and research and development work, but would not be efficient for use in large scale osmotic plants. First of all, a large scale osmotic process would comprise multiple cells and would require the use of hundreds of thousands, if not millions, of these relatively small conventional semipermeable membranes. Secondly, if such a massive number of conventional semipermeable membrane elements were used in a large scale osmotic process, the result would be an excessive pressure drop that would seriously impact plant efficiency and complicate plant operation and cost of maintenance.

[0006] More efficient semipermeable membrane elements are needed for use in designing large scale osmosis plants.

Summary

[0007] In one embodiment, the application provides an apparatus comprising: a membrane element comprising a hollow fiber (HF) stack comprising a plurality of loosely packed hollow fibers (HFs) comprising first ends extending through one contact structure and opposed ends extending through an opposed contact structure, each HF comprising an elongated lumen extending between the one contact structure and the opposed contact structure and comprising a hydrophilic semipermeable membrane adapted to achieve salt rejection of 98.5% or more and exhibiting a surface tension of 35 dynes/cm or more; the membrane element being adapted to be encased in a frame and submersed in a first fluid and for induced osmosis between lumens of the plurality of loosely packed HFs and the first fluid, the membrane element having sufficient mechanical integrity when encased in the frame and submersed in the first fluid to sustain turbulence flow across and along surfaces of the plurality of loosely packed HFs at a Reynolds' Number of about 3,000 or more and to maintain said mechanical integrity at feed pumping pressures of 30 bars or higher.

[0008] In one embodiment, the application provides a method comprising:

precharging HFs of one or more closed loops of the claimed apparatus with a process fluid having an initial solute content;

charging a feed through the one or more closed loops, the feed having a solute content greater than the initial solute content;

spontaneously permeating water from the feed to the process fluid in the HF lumens without the need for external force, producing a concentrated feed and a diluted process fluid.

[0009] In one embodiment, the application provides a method comprising:

precharging a plurality of the claimed closed loops of the apparatus in series with an initial brine having an initial salt concentration sufficiently high to create a hydraulic head effective to reach an intended elevation; spontaneously permeating water across a semipermeable membrane into a riser of an initial closed loop, the water permeating from a lower salt content brine to a higher salt content brine without the need for external force;

developing a column in the plurality of closed loops in series, the column exhibiting a hydraulic head equivalent to the difference in osmotic pressure across the semipermeable membrane of the respective closed loop;

employing the hydraulic head to sustain and convey the column from an initial closed loop at an initial elevation to a final closed loop at a

substantially higher intended elevation; and,

collecting a quantity of desalinated brine at the substantially higher altitude in a quantity comprising a volume of water that spontaneously permeates from the initial brine to the initial closed loop at an initial elevation. 10] In one embodiment, the application provides a method comprising: providing a power train comprising the claimed apparatus comprising a

plurality of cells, the plurality of cells comprising an initial end cell, one or more intermediate cells, and an opposed end cell, each cell in the plurality of cells forming a hydraulic loop configured of specified volumetric and flow capacity for a specified permeate flux, each cell in the plurality of cells also having a pumping system and a hydro-power generation turbine system, wherein adjacent cells in the plurality of cells share a semipermeable membrane;

charging each cell in the plurality of cells with a given brine having a specified ionizable inorganic salt concentration and type, without permitting mixing of the given brines among the adjacent cells in the plurality of cells, creating a gradient of salt concentration and resulting osmotic potential that progressively increases stepwise from the initial end cell, across the one or more intermediate cells, to the opposed end cell; feeding to the power train an initial brine comprising low to no salt

concentration water at the initial end cell, producing a concentration field across the plurality of cells comprising a progressively increasing concentration and osmotic pressure ratio bounded by water of low to no salt concentration at the initial end cell and by a concentrated brine at the opposed end cell, thereby producing a power train cycle comprising a controlled concentration-pressure loop wherein the concentration field: (a) osmotically induces a continuous and constant flow rate of substantially salt-free permeate flux throughout the power train; (b) maintains a salt concentration difference across the semipermeable membrane shared by the adjacent cells in the plurality of cells; (c) defines a salt concentration ratio within each cell that ensures a net positive power generation; and, (d) discharges the concentrated brine at the opposing end cell; and

operating the power train under conditions effective to generate net positive power.

11] In one embodiment, the application provides a method of making a membrane element comprising:

a. providing a plurality of detachable spacer structures having given dimensions;

b. placing one or more first spacer structures on an HF assembly

platform;

c. extending a first row of first HFs with first spaces therebetween over the one or more first spacer structures aligned with the longitudinal axis of the HF assembly platform, forming a first longitudinal row of first HFs, the first spaces having a width effective according to flow dynamic calculations to maintain turbulence flow across and along surfaces of the hollow fiber membranes at a Reynolds Number of 3,000 or more;

d. placing one or more second spacer structures having the given

dimensions over the first row of HFs aligned with the one or more first spacer structures;

e. extending an adjacent row of HFs with second spaces therebetween across the one or more second spacer structures aligned with the longitudinal axis of the HF assembly platform; f. repeating (d)-(e) with additional rows of HFs and spacer structures, forming a stack of alternating rows of HFs and intervening spacer structures, the stack having a desired total stack depth, wherein vertically aligned adjacent surfaces of the stacked spacer structures define potting chambers at opposed ends of the HFs, the potting chambers defining an inner surface having predetermined dimensions.

Brief Description of the Drawings

[00012] The application will be better understood with reference to the drawings. Where possible, like elements contain like numerals:

[00013] Figure 1 is a cross section through a plurality of vertical hollow fibers and one support member of a panel.

[00014] Figure 1A is a perspective view of an individual hollow fiber.

[00015] Figure 2 is perspective view of a pair of panels comprising perpendicularly oriented hollow fibers.

[00016] Figure 3 is a perspective view of an array for use in a power train, the array comprising a plurality of alternating perpendicularly oriented pairs of panels.

[00017] Figure 3A is an exploded view of panels from the array of Fig. 3.

[00018] Figure 3A-1 is a frontal view of a vertical fiber panel.

[00019] Figure 3A-2 is a side view illustrating fluid flow across the array of Fig. 3A-1.

[00020] Figure 3B is an exploded view of panels from a desalination array.

[00021] Figure 3C is a perspective view of a desalination array.

[00022] Figure 3D is a cross-section of a fiber reinforced plastic (FRP) panel for a hollow fiber panel.

[00023] Figure 3E is a cross-section of a steel frame or FRP for a hollow fiber panel

[00024] Figure 3F is a cutaway/transparent frame perspective view of a panel 10 (Fig. 2) comprising the header 16 and an adjacent header 26 (Fig. 2).

[00025] Figure 3G is a perspective view of a vertical baffle and a horizontal baffle. [00026] Figure 4 is a cross section through a plurality of conventionally packed hollow fibers.

[00027] Figure 5 is a cross section through of a plurality of loosely packed hollow fibers.

[00028] Figure 6 is a frontal view of a rectangular vessel at a vertical panel, the rectangular vessel being adapted for use with high pressures inside of the hollow fibers and low pressures outside of the hollow fibers.

[00029] Figure 7 is a cross section through a cylindrical vessel at a vertical panel, the cylindrical vessel being adapted for use with low pressures inside of the hollow fibers and high pressures outside of the hollow fibers.

[00030] Figure 8 is a top view illustrating an array comprising a plurality of segments of progressively differing diameters comprising a plurality of arrays having correspondingly differing cross-sections.

[00031] Figure 9 is a top view illustrating an alternate embodiment of the array of Figure 8 comprising an array casing comprising a continuously tapered diameter comprising a plurality of arrays comprising continuously tapering cross-sections.

[00032] Figure 9A is a schematic top view of a space saving arrangement of arrays for a power train.

[00033] Figure 9B is another schematic top view of a space saving arrangement for a power train.

[00034] Figure 10 is a top view of a power train comprising three cells of segmented arrays limited by maximum allowable operating pressure of the plurality ofHFs.

[00035] Figure 11 is a top view of a last cell in a power train comprising multiple cells comprising a pressure vessel comprising a plurality of segments of progressively differing diameters.

[00036] Figure 11A is a top view of a power train comprising a high pressure section and a low pressure section.

[00037] Figure 12 is a top view of a final two cells in a power train comprising multiple cells having the configuration of Fig. 11.

[00038] Figure 13 is a top view of a final cell of an exchanger comprising multiple pressure vessels having the structure generally described in Figure 11. [00039] Figure 14 is a top view of cell similar to Figure 11 comprising flexible feed conduits, the cell fitted with electromagnetic vibrators for concentration polarization control.

[00040] Figure 14A is a frontal view of a vertical panel in the cell of Fig. 14, illustrating a pair of the electromagnetic vibrators, a pair of spring mountings, and a pair of array casing support members.

[00041] Figure 15 is a top view of an integrated plant comprising the last cell of a large scale induced symbiotic osmosis (ISO) power train and a seawater desalination cell comprising an array similar to that of Figure 3C.

[00042] Figure 16 is a side view of a three cell water extraction- water recovery system 300 for concentrating diluted fluids by extracting its water content, particularly water contaminated with radioactive material.

[00043] Figure 17 is a schematic illustrating the pressures and tie lines of an ISO-Reverse Osmosis unit suitable for water extraction-fluid concentration.

[00044] Figure 18 is a cross section through a contact structure adapted to retain opposed ends of the HFs.

[00045] Figure 18A is a cross section of a HF indicating an inner and outer diameter.

[00046] Figure 19 is a cross section through the rows of HFs 34 that extend between contact structures in an intermediate phase during assembly with spacers therebetween.

[00047] Figure 20 is a perspective view of an assembly for manufacturing the membrane element.

[00048] Figure 21 is a cross section through the assembly of Fig. 20 with only two HFs, depicting the HFs as weighted.

[00049] Figure 22 is a top view of an assembly of Fig. 21 during manufacture of the HF panels.

[00050] Figure 23 is a side view of the assembly of Fig. 22.

[00051] Figure 24 is a cross section through an assembly comprising spacers adapted to form a potting structure, minus HF roll or loom heddle.

[00052] Figure 25 is a top view of one embodiment of a spacer. [00053] Figure 26 is a perspective view of the HF membrane element comprising opposed contact structures with layers of HFs extending therebetween.

[00054] Figure 27 is a top view of a HF membrane element with HFs extending between opposed contact structures showing a set of spacers aligned with finished baffles.

[00055] Figure 27A is a cross section through Fig. 27 at line X-X before injecting potting material.

[00056] Figure 27B is a cross section through Fig. 27 at line X-X after injecting and curing potting material.

[00057] Fig. 28A is a side view of an assembly for manufacturing the membrane element comprising two rolls one for the layer of even HFs and the second for the layer of odd HFs.

[00058] Fig. 28B is a top view of an assembly for manufacturing the membrane element comprising a wide HF wrap beam (roll) supporting two simultaneous HF panels assembly lines.

[00059] Fig. 28C is a perspective view of an assembly for manufacturing the membrane element comprising multiple spools of HFs.

[00060] Fig. 28D is a schematic top view of an assembly comprising a first spool row comprising an even number of HFs alternating with a second spool row comprising an odd number of HFs.

[00061] Fig. 28E is perspective view of an assembly for manufacturing reels of HFs from a plurality of spools.

[00062] Fig. 28F is a schematic top view of an assembly comprising a plurality of adjacent reels of HFs which may be spaced, as required, to produce the alternating rows of odd an even HFs.

[00063] Fig. 28G is a schematic view of a wrap beam assembly with the plurality of HFs extended from HF reels or spools being brought from different sources.

[00064] Fig. 29A and Fig. 29B, together, are an exploded view of a membrane element separated from a frame of one embodiment of a hollow fiber panel. Definitions

[00065] "Osmosis": The spontaneous movement of water, through a semipermeable membrane that is permeable to water but impermeable to solute, the water moving from a solution in which solute is less concentrated to a solution in which solute is more concentrated.

[00066] "Driving force": The difference in chemical potential on the two sides of a semipermeable membrane is the driving force of flow movement during osmosis. Water moves from a region of higher potential (generally a lower solute concentration) to the region of lower potential (generally higher solute concentration).

[00067] "Chemical potential": The energy potential associated with the activity of ions of an ionizable substance. The chemical potential is equal to the rate of change of free energy, known as Gibbs free energy, in a system containing a number of moles of such substance, when all other system parameters; temperature, pressure and other components are held constant. Like other kinds of potential (electrical, gravitational, momentum, magnetic, surface tension, etc.), chemical potential is spontaneous energy that flows in a direction from high to low.

[00068] "Spontaneous diffusion": Chemical potential is an intensive property of a substance in a phase. The difference in chemical potential of a substance in two adjacent phases separated by a semipermeable membrane determines whether and/or in which direction the substance will spontaneously diffuse through the semipermeable membrane. When the components of a mixture have the same chemical potential, there is no driving force and no mutual diffusion will occur.

[00069] "Osmotic pressure": In order to prevent water from moving across a semipermeable membrane, a pressure must be imposed to equalize the force created by a given difference in the chemical potential of the solution across said membrane. This force is named osmotic pressure.

[00070] "Reverse Osmosis": If an imposed pressure exceeds the osmotic pressure, then water will flow from a region of higher solute concentration to a region of lower solute concentration in a process called Reverse Osmosis. In this case, the driving force is called reverse osmosis pressure.

[00071] "Induced osmosis": Applications described herein that use the power of osmosis to perform a variety of functions for the benefit of mankind. [00072] "Symbiosis": A mutual relationship of cyclic reverberation, without altering or modifying any of the specific components of the involved systems. Symbiosis is used to optimize industrial applications by using a waste or less valuable byproduct in one industry as a resource for use in one or more other industries.

[00073] "Induced Symbiotic Osmosis" or "ISO": spontaneously inducing continuous transient flow of permeated water through a power train comprising a plurality of fluidic loops of fixed volumetric capacity and solute concentration, bounded by semipermeable membranes , the continuous transient flow of permeated water from a low salinity water source, under the influence of an osmotic gradient to capture the kinetic potential of said transient flow within each loop, without influencing the content of said loop, the transient flow (hereafter sometimes referred to as a "Tie-Line") being continuous and at a constant flow rate throughout adjacent fluidic loops forming the power train.

[00074] "Large Scale Renewable Energy (LSRE) system": a system that generates electric power of about 25,000 kWh or more, or provides electric power to a community of about 25,000 people or more.

[00075] "Tie-Line": Water permeates by induced osmosis into the HFs at a specified permeate rate. In one embodiment, the specified permeate rate is constant throughout all the cells of a given power train. In one embodiment, the water has essentially the same purity throughout the tie-line. The direction in which the tie-line flows, and the specified permeate rate, will vary depending upon a variety of factors including but not necessarily limited to the internal HF and external HF pressure and the salinity of the respective process fluid and feed. The tie-line may have a specified permeate rate that is several times that of the feed without adversely impacting HF integrity. In some embodiments, the tie-line is assumed to have a permeate rate of a unit of volume per second, i.e. m ³ /s or L/s. The water permeate has as high a purity as possible. The purity of the water permeate will depend, at least in part, on the semipermeable membrane used. In one embodiment, the "water" permeate has a salinity of 1.5% or less. In one embodiment, the "water" permeate has a salinity of 1.5% or less; 1.4% or less; 1.3% or less; 1.2% or less; 1.1% or less; 1 % or less; 0.5% or less; 0.4% or less; 0.3% or less; 0.2% or less; 0.1% or less. In one embodiment, the water permeate is 100% pure water. [00076] "Cell": the fluidic embodiment encompassing the volumetric capacity shared between two adjacent Induced Symbiotic Osmosis HF membrane exchangers, comprising the volume of hollow fiber membrane lumens in one HF membrane exchanger and the volume of the vessel space outside of the HF membrane in the downstream adjacent exchanger. Initially, this volumetric capacity is charged with a fixed volume of saline solution of a specific salt concentration and maintained in continuous circulation by means of one or more pumping system fluidly communicating with the HF lumens in one of the exchangers and one or more power generation hydraulic turbine fluidly communicating with the hollow fiber external surface in the downstream adjacent exchanger. When such a cell is placed in an osmotic potential field, essentially salt-free water crosses the tie-line from one exchanger to the other, causing transient increase in the pumped brine flow rate associated with a reduction in concentration of the pumped brine. This phenomenon is reversed when the hydraulic turbine transport flows across the downstream adjacent exchanger.

[00077] The foregoing definitions are not exhaustive, and additional definitions may be found in the following detailed description.

Detailed Description

[00078] The present application incorporates principles published in United States Publication Number 2011/0044824, issuing/issued October 1, 2013 as U.S. Patent No. 8,545,701, the full text of which is incorporated herein by reference.

[00079] The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.

[00080] In one embodiment, the application provides apparati and processes of making same, for efficiently exchanging low or no solute solutions with high or hypersolute aqueous solutions. In one embodiment, the low or no solute solutions are saline solutions. The apparati may be used in a large variety of processes, including but not necessarily limited to water micro filtration, ultra filtration, nanofiltration purification (reverse osmosis), extraction, salinity power generation and gas mixture separation (landfill gases as an example), and combinations thereof.

The Membrane Element

[00081] Hollow fibers are generally more economical than other types of membrane design. Hollow fibers have the advantage of allowing for a large membrane area per unit volume. Accordingly, hollow fiber systems may be relatively compact systems.

[00082] In one embodiment, referring to Figure 29 A, the application provides a membrane element 3000 comprising: a hollow fiber (HF) stack comprising a plurality of loosely packed hollow fibers (HFs) 14 comprising first ends extending through one contact structure 906 and opposed ends extending through an opposed contact structure 906a, each HF comprising an elongated lumen extending between the one contact structure 906 and the opposed contact structure 906a and comprising a hydrophilic semipermeable membrane adapted to achieve salt rejection of 98.5% or more and exhibiting a surface tension of 35 dynes/cm or more. The membrane element 3000 is adapted to be encased in a frame 12 (Fig. 29B) for a HF panel 10 of Figure 1. The plurality of loosely packed HFs 14 are adapted to be submersed in a first fluid and to sustain turbulence flow across and along surfaces of the plurality of loosely packed HFs 14 at a Reynolds' Number of about 3000 or more.

Hollow Fiber Panel

[00083] In one embodiment, referring to Figure 1, the HF panel 10 comprises: the frame 12 comprising a header 16, an opposed header 16a, and the membrane element 3000 (Fig. 29A, described above) retained within the frame 12. The membrane element 3000 (Fig. 29A) comprising the plurality of loosely packed HFs 14 engaged at each end by the first and second contact structure (906, 906a, Fig. 29A) is adapted to provide fluid communication between lumens of the plurality of loosely packed HFs 14, the header 16, the opposed header 16a, and any adjacent frames and panels. The HF panel 10 is adapted for submersion in a first fluid and for induced osmosis between lumens of the plurality of loosely packed HFs 14 in the membrane element 3000 (Fig. 16, Fig. 29A) and the first fluid. The HF panel 10 has sufficient mechanical integrity to sustain turbulence flow across and along surfaces of the plurality of loosely packed HFs 14 at the Reynolds' Number of about 3,000 or more and to maintain said mechanical integrity at feed pumping pressures of 30 bars or higher.

[00084] In one embodiment, the frame 12 may have a variety of shapes (in frontal view) including, but not necessarily limited to circular, elliptical, triangular, and rectangular. In the embodiment shown in Fig. 1, the frame 12 is square (in frontal view) and comprises a first header 16 and an opposed header 16a, and a first support 19 and second support 19a. In one embodiment, one or both of the first header 16 and the opposed header 16a have a depth 18.

[00085] The plurality of HFs 14 comprise a plurality of loosely packed individual HFs 1 (Fig. 1A) comprising a semipermeable membrane defining a lumen. In one embodiment, the semipermeable membrane is adapted to retain its mechanical integrity at higher feed pumping pressures across the lumens and higher process fluid pressures inside of the lumens compared to low pressure microfiltration and ultrafiltration HF membranes currently in use in the industry.

[00086] The actual feed pressure to which the HF panel 10 comprising the HF membrane element 3000 (Fig. 19A) will be exposed will differ depending upon the process being performed, the initial salinity of the process fluid and the feed, and the tie-line flow. Induced osmosis of water having salinity of 1% generates an osmotic head equivalent to 7.75 bars. At 6% salinity, the osmotic head is equivalent to 46.5 bars. In general, the sustainable feed pumping pressure must be sufficiently high to overcome this osmotic head. For example, in the case of desalination of seawater (3.5% salinity) by reverse osmosis, where concentrated brine leaves at 6 % salinity and produces an osmotic pressure of 46.5 bars, the sustainable feed pumping pressure must be higher than the osmotic head of 6%.

[00087] In one embodiment, the semipermeable membrane maintains mechanical integrity at a feed pressure of: 30 bars or higher, 31 bars or higher; 32 bars or higher; 33 bars or higher; 34 bars or higher; 35 bars or higher; 36 bars or higher; 37 bars or higher; 38 bars or higher; 39 bars or higher; 40 bars or higher; 41 bars or higher; 42 bars or higher; 43 bars or higher; 44 bars or higher; 45 bars or higher; 46 bars or higher; 47 bars or higher; 48 bars or higher; 49 bars or higher; or, 50 bars or higher.

[00088] In one embodiment, the semipermeable membrane material "rejects" solute, or does not permit solute in a solution to pass through the membrane. In one embodiment, the solute is salt, and the semipermeable membrane material rejects salt. In one embodiment, the salt is primarily sodium chloride.

[00089] The higher the effective solute rejection, the more efficient the operation of the membrane. In one embodiment, the semipermeable membrane is effective to reject 98.5% or more of the solute in the feed. In one embodiment, the semipermeable membrane is effective to reject the following percent of salt in the feed: 98.1%; 98.2%; 98.3%; 98.4%; 98.5%; 98.6%; 98.7%; 98.8%; 98.9%; 99%; 99.1%; 99.2%; 99.3%; 99.4%; 99.5%; 99.6%; 99.7%; 99.8%; 99.9%; aboutl00%.

[00090] The selection of suitable semipermeable membrane(s) for a particular process should be based on performance and economics in the particular process. Suitable membranes include, but are not necessarily limited to stirred cell membranes, flat sheet tangential flow membranes, tubular membranes, capillary membranes, spiral-wound membranes, hollow fiber membranes, other high operating pressure semipermeable membranes in the form of small bore cylinders, and combinations thereof.

[00091] The membrane processing technologies of microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) are widely used to separate suspended and dissolved materials from water solutions in numerous industrial, medical and drinking water applications. MF typically is used to separate or remove suspended or colloidal particulates having a maximum diameter of from about 0.1 to about 1.0 microns (about 1,000 to about 10,000 angstroms). UF typically is used to separate or remove dissolved materials depending upon solute size, which typically comprise a maximum diameter of from about 0.001 microns to about 0.1 microns (about 10 angstroms to about 1,000 angstroms). NF and RO typically are used to separate or remove materials having a maximum diameter of less than about 0.001 micron (about 10 angstroms).

[00092] Common membrane materials include polyamide thin film composites (TFC), polysulfone, polypropylene, cellulose acetate (CA), cellulose triacetate (CTA) and others. For commercial large RO systems, spiral wound and HF membranes are the primary candidates. Suitable membrane materials are hydrophilic.

[00093] Existing technologies suffer from what is known as concentration polarization phenomenon. The use of hydrophilic semipermeable membranes in HF panels significantly mitigates this phenomenon. Hydrophilic literally means "water- loving." Accordingly, a hydrophilic material exhibits an affinity for water, and tends to readily adsorb water.

[00094] Suitable hydrophilic semipermeable membranes have a surface tension sufficiently high to maintain materials at the surface of the semipermeable membrane in liquid form. In one embodiment, the surface tension of the hydrophilic semipermeable membrane is about 35 dyne/cm or more. In one embodiment, the surface tension is about 36 dyne/cm or more; 37 dyne/cm or more; 38 dyne/cm or more; 39 dyne/cm or more; 40 dyne/cm or more. In one embodiment, the surface tension of the hydrophilic semipermeable membrane is from about 40 to about 45 dyne/cm. In one embodiment, the surface tension of the hydrophilic semipermeable membrane is about 41 dyne/com; 42 dyne/cm; 43 dyne/cm; 44 dyne/cm; or 45; dyne/cm. In one embodiment, the hydrophilic semipermeable membrane material has a surface tension of about 44 dyne per centimeter or more.

[00095] Hydrophilic membrane materials having suitable surface tensions include, for examples, Polyepichlorohydrin (surface tension-35), Polyvinyl Chloride (PVC) (surface tension-39), Polysulfone (surface tension-41), Polyethylene Terephthalate (Polyester) (surface tension -43), Polyacrylonitrile (surface tension-44); Cellulose (surface tension- 44), and variants thereof.

[00096] In one embodiment, the hydrophilic semipermeable membrane material is cellulose acetate. Cellulose acetate has a surface tension of 44 dyne per centimeter (dyne/cm). In one embodiment, the hydrophilic semipermeable membrane is a cellulose triacetate (CTA) membrane. A suitable CTA semipermeable membrane is commercially available from the Japanese corporation, Toyobo Co, Ltd.

[00097] The individual HFs 1 of Figure 1A have a first end 13, an opposed end 13a, and a length 2 of semipermeable membrane defining a lumen. The HFs define a lumen having a variety of shapes including, but not necessarily limited to tubular, elliptical, triangular, and rectangular. In one embodiment, the HFs 1 are tubular. A person of ordinary skill in the art will recognize that the components of the present application may have a variety of sizes. The lumen diameter may vary. In one embodiment, the lumen diameter is from about 50 micrometer to about 2000 micrometer (2 mm).

[00098] The plurality of HFs 14 has a "loosely packed" configuration. Figure 4 is a cross section through a HF bundle having a conventional tightly packed configuration. As seen in Fig. 4, in a tightly packed conventional configuration, the walls (la - le) of adjacent HFs either touch or have boundary layers that are so close that they form stagnation areas 52, 52a between which fluid cannot freely flow. These stagnation areas 52, 52a tend to negatively impact the efficiency of the osmotic processes using the HF bundle. Fig. 5 is a cross section through a plurality of HF's 14 of the present application, which are loosely packed. As seen in Fig. 5, the walls 5a- 5e of adjacent HFs do not touch, or are sufficiently spaced to avoid forming stagnation areas between the HFs. This tends to prevent stagnation and improve the efficiency of the osmotic process performed using the plurality of HFs. This also tends to reduce the potential to form concentration polarization sites.

[00099] In one embodiment, referring to Figure 3G, the plurality of HFs 14 in each frame are retained in a loosely packed configuration by one or more horizontal baffles 720 and/or one or more vertical baffles 710. In one embodiment, the plurality of HFs 14 in each frame are retained in a loosely packed configuration by a plurality of spaced horizontal baffles 720 and/or vertical baffles 710. The baffles may be external baffles which are removable from the HF frame 12, or the baffles may be integrated into the HF frame 12, as described more fully below.

[000100] The external baffles may have a variety of constructions. In one embodiment, each baffle comprises a backing with suitable retainers extending therefrom, as depicted in Fig. 3G. In one embodiment, the baffle is a vertical baffle comprising backing 710. In one embodiment, the baffle is a horizontal baffle comprising backing 720. In one embodiment, the retainers are spikes. In one embodiment, the retainers are wire loops. Spaced wire loop baffles are useful to avoid damaging the plurality of HFs. The size of the backing 710, 720 will vary with the size of the panel. The spikes or wire loops 712, 722 have a length 714, 724 sufficient to extend through and inhibit movement of the plurality of HFs. In one embodiment, the baffles 710, 720 and the extensions 710, 712 are in fixed communication with the frame. In one embodiment, the baffles are bolted to the frame.

[000101] In one embodiment, once positioned in a given system, the HFs in a frame run vertically and the panel comprises one or more horizontal baffles 720. Referring to Fig. 3G, each horizontal baffle comprises backing 720 comprising a plurality of appropriately spaced wire loops 722. The spikes or wire loops 722 are spaced along the backing 720 at intervals effective to retain the plurality of HFs running vertically in a loosely packed configuration and to prevent sagging when the spikes or wire loops 722 are inserted through the plurality of HFs. The intervals between spikes or wire loops 722 may vary. In one embodiment, the spikes or wire loops 722 in a horizontal baffle are spaced at larger intervals than in a vertical baffle. In one embodiment, the spikes or wire loops 722 in a horizontal baffle are spaced from about 6 to 12 inches apart. Once inserted through the plurality of HFs, the spikes or wire loops 722 reduce movement of the plurality of HFs. In one embodiment, the horizontal baffles 720 are spaced apart across the plurality of HFs. The space between the horizontal baffles 720 is effective to retain the plurality of HFs running vertically in a loosely packed configuration and to prevent sagging. In one embodiment, the space between horizontal baffles 720 is from about 20 cm to about 30 cm.

[000102] In one embodiment, the HFs in the frame run horizontally and the panel comprises one or more vertical baffles 710. Referring to Fig. 3G, each vertical baffle comprises backing 710 comprising a plurality of appropriately spaced wire loops 712. The spikes or wire loops 712 are spaced along the backing 710 at intervals that are effective to retain the plurality of HFs running horizontally in a loosely packed configuration and to prevent sagging when the spikes or wire loops 712 are inserted through the plurality of HFs. The intervals between spikes or wire loops 712 may vary. In one embodiment, the spikes or wire loops 712 in a vertical baffle are spaced at smaller intervals than in a horizontal baffle. In one embodiment, the spikes or wire loops 712 in a vertical baffle are spaced from about 1 to 2 inches apart. Once inserted through the plurality of HFs, the spikes or wire loops 712 reduce movement of the plurality of HFs. In one embodiment, the vertical baffles 710 are spaced apart across the plurality of HFs. The space between the vertical baffles 710 is effective to retain the plurality of HFs running horizontally in a loosely packed configuration and to prevent sagging. In one embodiment, the space between vertical baffles 710 is from about 20 cm to about 30 cm.

[000103] The backing 710, 720 may be made of a variety of materials, including but not necessarily limited to metal, plastic, and combinations thereof. In one embodiment, the backings 710, 720 are made of polypropylene. In one embodiment, the backings 710, 720 are made of fiber reinforced plastic. The spikes or wire loops may be made of any suitable material, including but not necessarily limited to metal and plastic. In one embodiment, the spikes or wire loops comprise steel. In one embodiment, the spikes or wire loops are coated with a suitable corrosion protection material. Substantially any corrosion protection material may be used. In one embodiment, the corrosion protection material is Teflon. In one embodiment, the corrosion protection material is epoxy.

[000104] The frame is adapted to permit (a) induced osmosis between lumens of the plurality of hollow fibers and a surrounding environment and (b) fluid communication between the lumens of the plurality of hollow fibers and any adjacent panels. Referring to Fig. 1, in one embodiment, the plurality of HFs 14 are loosely packed substantially parallel to one another to form a first edge 11 and an opposed edge 11a. In one embodiment, the first edge 11 abuts the support member 19 and the opposed edge 11a abuts the opposing support member 19a.

[000105] In one embodiment, first ends 13 of the plurality of HFs 14 fluidly communicate with a first header 16. In one embodiment, the opposed ends 13a of the plurality of HFs 14 fluidly communicate with an opposed header 16a. [000106] Referring to Fig. 29A, the stack of loosely packed HFs 14 (the HF stack) in the membrane element 3000 has a width 3002, a height 3004, and a depth 3005. In one embodiment, the HF stack width 3002 is the same as the HF stack height 3004. In one embodiment, the HF stack width 3002 is about 3 meters. In one embodiment, the HF stack has a depth 3005 of from 40 to about 80 mm.

[000107] The contact structures 906, 906a (or 1006 in Fig. 3E) at each end of the loosely packed HFs 14 have a length 3006, a width 3008, and a thickness 3010. In one embodiment, the contact structure length 3006 is slightly larger than the HF stack width 3002, and the contact structure width 3008 is slightly larger than the HF stack depth 3005 to allow for proper support of the HF stack 14 on the frame of Fig. 29B. In one embodiment, the HF stack depth 3005 is 40-80 mm. In one embodiment, the HF stack depth 3005 is about ³ A of the contact structure width 3008. In one embodiment, the contact structure thickness 3010 is from about 20 to 60 mm, depending on operating pressure.

[000108] The frame 12 (Fig. 29B) has a header 16 and an opposed header 16a. The frame has a frame width 3012, a frame height 3014, and a frame depth 3016. In one embodiment, the frame width 3012 is the same as the frame height 3014. In one embodiment, the frame depth 3016 is from about 1.5 - 2 times the contact structure width 3008 for proper support of the membrane element 3000.

[000109] Referring to Figure 2, the HF panel 10 (of Fig. 1) abuts an adjacent HF panel 20 having a similar structure to HF panel 10. The adjacent HF panel 20 comprises a plurality of hollow fibers 24. The adjacent HF panel 20 in Figure 2 has a square frame comprising a first header 26 and an opposed header 26a, a first support 29 and an opposed support (not shown). In one embodiment, the lengths 2 (Fig. 1A) of the plurality of hollow fibers 24 in the adjacent HF panel 20 are at an angle relative to the lengths 2 (Fig. 1A) of the plurality of hollow fibers 14 in the HF panel 10. In Fig. 2, the lengths 2 (Fig. 1A) of the plurality of hollow fibers 24 in the HF panel 20 are oriented substantially perpendicular to the lengths 2 (Fig. 1A) of the plurality of hollow fibers 14 in the HF panel 10. In this embodiment: the opposed header 16a of the HF panel 10 abuts the first support member 29 of the adjacent HF panel 20; the header 16 of the HF panel 10 abuts the opposed support member (not shown) of the adjacent HF panel 20; the support member 19 of the HF panel 10 abuts the first header 26 of the adjacent HF panel 20; and the support member 19a abuts the opposed header 26a of the adjacent HF panel 20.

[000110] In one embodiment, header 16 comprises a first aperture 22 adjacent to support 19 and the opposed header 16a comprises an aperture 23 adjacent to opposed support 19a. The apertures 22, 23 may have a variety of shapes including, but not necessarily limited to circular, elliptical, triangular, rectangular, and combinations thereof. In one embodiment, the apertures 22, 23 are circular. In one embodiment of a power train, the aperture 22 communicates with a source of process fluid (not shown).

[000111] In one embodiment, the HFs 25 and 24 are loosely packed (a) between the first header 16 and the opposed header 16a, and (b) between the opposed headers 26 and 26a in Fig. 2, respectively. In one embodiment, the packing is sufficiently loose for feed to flow across the array substantially perpendicular to the HF panels 10, 20 at a given flow rate and feed capacity without stagnation, but sufficiently tight to provide the desired processing capacity. The frame 12 of the HF panel 10 comprises the headers 16, 16a and the supports 19, 19a, the frame of adjacent HF panel 20 comprises the headers, 26, 26a and the support 29 (and the opposed support, not shown).

[000112] The headers and supports comprise a material and structure having sufficient mechanical integrity to retain the plurality of HFs 24, 25 when exposed to a substantially perpendicular flow of feed at a specified operating pressure. The frame 12, as well as other components, such as the array casing, may be made of a variety of materials including, but not necessarily limited to fiber reinforced plastic (FRP). Fiber-reinforced plastic (FRP) (also sometimes called fiber-reinforced polymer) is a composite material made of a polymer matrix reinforced with fibers. Common fibers include, but are not necessarily limited to glass, carbon, basalt, aramid, paper, wood, asbestos, and the like. In one embodiment, the fibers are selected from the group consisting of glass, carbon, basalt, aramid, and combinations thereof. Common polymers include, but are not necessarily limited to thermosetting plastics selected from the group consisting of epoxy, vinyl ester, polyester, phenol-formaldehyde resins, and combinations thereof. [000113] Suitable FRP's meet or exceed the mechanical properties of steel. In one embodiment, the FRP exhibits superior thermo-mechanical properties, is light weight, is relatively low cost, exhibits corrosion resistance, and is easy to maintain. In one embodiment, headers and supports are made of the same material. In one embodiment, the headers and supports are made of different materials. In one embodiment, the headers and/or supports are made of steel (Figure 3E). In one embodiment, the headers and/or supports are made of FRP. In one embodiment, the headers and the supports are made of FRP.

[000114] The membrane element and HF panel are useful in a variety of ISO apparati and processes. Suitable ISO apparati and processes include, but are not necessarily limited to those for ISO power generation, reverse osmosis, desalination, and water extraction from diluted organic, contaminated groundwater and industrial solutions. The HF panel 10 is particularly useful to perform large scale ISO processes. In one embodiment, the process fluid 15 (or fluid inside of the HF lumen) is at a relatively high pressure and the feed (or fluid outside of the lumen) is at a relatively low pressure.

[000115] The salinity (or solute concentration) of the process fluid 15 and the feed 17 will vary. The process fluid 15 for an extraction process typically has a moderate salinity. In one embodiment, the moderate salinity is from about 3% to about 7%. The process fluid 15 for osmotic power generation and/or seawater desalination by reverse osmosis will have a low salinity, typically less than about 3%. In one embodiment, the process fluid 15 is at a relatively low pressure and the initial feed is at a relatively high pressure. In one embodiment, the process fluid 15 is at a relatively low pressure of from about 3 bars to about 5 bars and the feed 17 is at a relatively high pressure of from about 10 bars to about 60 bars or more, depending of on feed salinity. In one embodiment, the conditions are optimized to produce a tie- line, as defined herein and more fully described in ISO US Patent No. 8,545,701, having a flow rate that varies from less than 1 liter/sec to a flow rate of several cubic meters/sec. In one embodiment, the conditions are optimized to produce a tie-line having a flow rate of greater than 1 mVsec. In one embodiment, the tie-line has a flow rate of 3 m ³ /sec or more. In one embodiment, the tie-line has a flow rate of 5 m ³ /sec or more. In one embodiment, the tie-line has a flow rate of 10 mVsec or less. [000116] In one embodiment, the pressure differential between the process fluid within the HF lumens and the feed outside of the HF lumens, respectively, is 5 bars or more. In one embodiment, particularly in the case of treating water contaminated with radioactive material, relatively low pressure differential is used, at least initially, to avoid radioactive particles penetrating the semipermeable membrane. In one embodiment treating water contaminated with radioactive material, the operating pressures within the HF lumens and the outside of the HF lumens in an initial closed loop maintain a pressure differential of 10 bars or less in the initial closed loop. In one embodiment treating water contaminated with radioactive material, the operating pressures within the HF lumens and the outside of the HF lumens in an initial closed loop maintain a pressure differential of less than 10 bars in the initial closed loop. In one embodiment treating water contaminated with radioactive material, the operating pressures within the HF lumens and the outside of the HF lumens in a final high pressure closed loop in series maintains a pressure differential of 5 bars or higher in the final high pressure closed loop. In one embodiment, particularly when the process is ISO power generation and reverse osmosis, the pressure differential is 40 bars or more. In one embodiment, for power generation, the pressure differential is 30 bars or more.

[000117] Accordingly, depending upon the process performed, the pressure differential is: from 5 bars or more to 10 bars or less (esp. water contaminated with radioactive material); in other processes, 15 bars or more; 20 bars or more; 25 bars or more; 30 bars or more (esp. power generation); 31 bars or more; 32 bars or more; 33 bars or more; 34 bars or more; 35 bars or more; 36 bars or more; 37 bars or more; 38 bars or more; 39 bars or more; 40 bars or more (power generation and reverse osmosis); 41 bars or more; 42 bars or more; 43 bars or more; 44 bars or more; 45 bars or more; 46 bars or more; 47 bars or more; 48 bars or more; 49 bars or more; 50 bars or more; 51 bars or more; 52 bars or more; 53 bars or more; 54 bars or more; 55 bars or more; 56 bars or more; 57 bars or more; 58 bars or more; 59 bars or more; or, 60 bars or more.

[000118] The feed 17 flows substantially perpendicular to and across the HF panel 20, and the HF panel 10, producing a modified feed 17b. The modified feed 17b has a different flow rate and composition than the feed 17 caused by water spontaneously permeating from or into the HFs 14 that are stretched across the frame 12. Process fluid 15 (Fig. 1) flows through the aperture 22 and into the first header 16. The process fluid 15 flows from the first header 16 into the lumens of the plurality of HFs 14 and in a direction 13b to the opposed header 16a. Modified process fluid 21 (Fig. 1) flows through an aperture 23 out of opposed header 16a. In one embodiment, the modified process fluid 21 flows into an adjacent header 26a (Fig. 2).

[000119] Although relatively low lumen operating pressures (e.g., 3-5 bars) may not be sufficient for power generation, HF panels having such low lumen pressures may still be used to provide support functions. In one embodiment, HF panels having low lumen operating pressures are used to perform water filtration. In one embodiment, HF panels having low lumen operating pressures are used to perform ISO extraction.

[000120] In one embodiment, the process fluid is seawater. In one embodiment, the feed is brackish water or agricultural drainage. In this embodiment, water spontaneously permeates from the feed (brackish water or agricultural drainage) to the seawater in the HF lumens, diluting the seawater.

[000121] The HF stack cross section 11 of the plurality of HFs 14 in the frame 12 of Figure 1 and the HF stack cross section 18a of the plurality of HFs 24 in the frame of HF panel 20 of Figure 2 may vary in size according to application. In one embodiment, the HF stack cross section 11 and the HF stack cross section 18a are different. In one embodiment, the HF stack cross section 11 and the HF stack cross section 18a are the same.

[000122] Referring now to Figure 3, a power array 30 comprises a plurality of sequentially abutting pairs (A, B, C) of HF panels. In one embodiment, spaced horizontal baffles 720a, 720b, 720c are visible on a tail panel. In this embodiment, an initial feed 37 is charged to the power array 30 at an angle substantially perpendicular to and across the respective plurality of HFs 34-34e in each panel to exit as a modified feed 37a. In one embodiment, where the initial feed is a high salinity feed, the initial feed 37 is at a pressure of from about 30 bars to about 50 bars and the process fluid 35 is at a pressure of from about 1 bar to about 5 bars.

[000123] In one embodiment, initial process fluid 35 having a relatively low salinity flows through the aperture 38 and into the header 36, from the header 36 through the plurality of HFs 34 in a direction 39a, producing a modified initial process fluid 33 that flows into an opposed header 36a from the opposed lumens. The modified initial process fluid 33 flows through an aperture 32a- 1 and through an abutting aperture 32a-2 (Fig. 3A) into an adjacent header 36b, through the plurality of HFs 34a, producing a second modified process fluid (not shown) that flows into an opposed header 36c. The second modified process fluid (not shown) flows through a first aperture (not shown) and through an abutting aperture 32b-2 (Fig. 3A) into an adjacent header 36d. The second modified process fluid (not shown) flows through the plurality of HFs 34b, producing a third modified process fluid 33c that flows into the header 36e. The third modified process fluid 33c flows through an aperture 32c-l into header 36f, from header 36f (Fig. 3) through the plurality of HFs 34c into opposed header 36g, producing a fourth modified process fluid (not shown). The fourth modified process fluid (not shown) flows from header 36g through abutting apertures (not shown) into adjacent header 36h, through the plurality of HFs 34d to produce a fifth modified process fluid 33d. The fifth modified process fluid flows through aperture 32e-l and an abutting aperture into an adjacent header 36j, through the plurality of HFs 34e, into the header 36k producing a sixth modified process fluid (not shown). In the embodiment shown in Fig. 3 the sixth modified process fluid (not shown) exits through an aperture (not shown) in the header 36k. In one embodiment, the sixth modified process fluid is collected. In one embodiment, the sixth modified process fluid 31 flows to the next array. Referring to Fig. 3A, the spaced horizontal baffles 720a, 720b, 720c and spaced vertical baffles 710a, 710b, 710c are visible on the respective panels. The baffles are described in more detail below.

[000124] Figure 3A-1 is frontal view of a vertical fiber panel at a cross section through a rectangular array comprising a casing 49. Fig. 3A-2 is a top view of the array of Fig. 3A-1 comprising the array casing 49.

[000125] Referring to Figure 3A-1, process fluid is introduced into the header 41 and flows through the HFs to an opposed header 41a. In one embodiment, referring to Fig. 3A-2, a high salinity brine feed 43 is charged to the array 45, and flows from and across a tail panel 47a to and across an initial panel 47b of the array 45. In one embodiment, the total area (width x length) of the frontal view across which the feed flows is up to 100 times larger than the corresponding area across which the feed flows in a conventional, commercially available tube-like high pressure membrane array. The modified feed 43a exiting the array 45 is a low salinity product, typically at a higher flow rate than the high salinity brine feed 43.

[000126] Figure 3B depicts a typical cross flow pattern in a desalination array 3. In one embodiment, the desalination panels operate relatively independently. In one embodiment, a brine feed 44 is charged at a relatively high pressure to and across the desalination array 3. In one embodiment, the brine feed 44 is seawater. Where the brine feed 44 is seawater, the seawater 44 passes across the array and water passes from the seawater into the HFs, producing desalinated seawater 47. A relatively high salinity brine 44a exits the array. Spaced horizontal baffles 720a, 720b, 720c and spaced vertical baffles 710a, 710b, 710c are visible the respective panels. The baffles are described in more detail below.

[000127] Figure 3C is a perspective view of desalination array 705 comprising pairs of substantially perpendicularly oriented panels (A, B, C). In one embodiment, seawater 700 is fed across the array to and across a tail panel 702 at a relatively high pressure. As the seawater 700 passes from the tail panel 702 across the array to an initial panel 704, water flows from the seawater into the lumens of the HFs, producing desalinated seawater 708. A relatively higher salinity brine 700a exits the initial panel 704. Spaced horizontal baffles 720a, 720b, 720c are visible on the tail panels. The baffles are described in more detail below.

[000128] In one embodiment, the process fluid travels through the headers via a pipe structure. The pipe structure may have a variety of configurations. Figure 3D is a cross section at 900'-900" in Figure 3A illustrating one embodiment 900 of a pipe structure. In one embodiment, the pipe structure 3D comprises fiber reinforced plastic. Referring to Figure 3D, in this embodiment, the header comprises a rectangular support structure 902. In one embodiment, a pipe 904 is retained within the rectangular support structure 902. In one embodiment, the rectangular support structure 902 is a solid structure defining a bore therethrough. In Fig. 3D, the rectangular support structure 902 is a frame with a pipe 904 extending therethrough. In one embodiment, the rectangular support structure 902 and the pipe 904 comprise fiber reinforced plastic. In one embodiment, the rectangular support structure comprises one or more pressure equalizer openings 904a-d. In this embodiment, the contact points between the rectangular support structure 902 and the pipe 904 are secured using any suitable means. In one embodiment, the contact points between the rectangular support structure 902 and the pipe 904 are secured using cement, adhesive, or other suitable material. In one embodiment, epoxy cement is used to secure the rectangular support structure 902 to the pipe 904. In one embodiment, gasket material 906a is provided between frames at opposed sides of the rectangular support structure 902.

[000129] In one embodiment, the plurality of hollow fibers 34 (or 14, 24 in Figs.

1 and 2, respectively) extend through a contact structure 906 (Fig. 3D) or 1006 (FIG 3E) adapted to retain the plurality of HFs 34 in a loosely packed arrangement. The contact structure 906 (or 1006 in Fig. 3E) may be any suitable material (2000 in Fig.

8). In one embodiment, the contact structure 906 (or 1006 in Fig. 3E) comprises a suitable thermosetting material. In one embodiment, the contact structure 906 is selected from the group consisting of epoxy, polyurethane, and combinations thereof. As seen in Fig. 3D, the ends 13 (Fig. 1A) of the hollow fibers 34 empty into the pipe

904.

[000130] Figure 18 is a cross section through a contact structure 906 at line A- A' in Fig. 29A. The contact structure 906 or 1006 (Fig. 3E) comprises cured potting material 2000 with embedded alternating rows of HFs 34. In one embodiment, the embedded alternating rows of HFs 34 form abutting rows of hexagonal structures 2006 around a central HF 34c. The contact structure 906 or 1006 (Fig. 3E) may be made in any desired size. In one embodiment, the contact structure 906 or 1006 has a width 2003 (3008 in Fig. 29A) of about 55-105 mm. In one embodiment, the contact structure 906 or 1006 has a thickness (3010 in Fig. 29 A) of about 20-60 mm. In one embodiment, the contact structure 906 or 1006 has a length 2001 (3006 in Fig. 29 A) of up to 3,000 mm (3m).

[000131] The inner and outer diameter of the HFs 34 will vary depending upon the application and process parameters. In one embodiment, referring to Fig. 18A, the HFs 34 have an outer diameter D ₀ of from about 200-3,000 micrometers (0.2 - 3 mm). The outer diameter (D ₀ ) will vary depending upon the desired feed pressure. HFs having a smaller outer diameter (D ₀ ) will withstand higher feed pressures. For example, HFs having an outer diameter (D ₀ ) of 0.2 mm for reverse osmosis desalination can withstand feed pressures as high as 70 bars. In contrast, HFs having an outer diameter (D ₀ ) of 3 mm for water microfiltration can withstand relatively lower feed pressure of just a few bars.

[000132] In one embodiment, the outer diameter (D ₀ ) of the HFs 34 is: 0.2 mm; 0.3 mm; 0.4 mm; 0.5 mm; 0.6 mm, 0.7 mm; 0.8mm; 0.9 mm; 1 mm; 1.1 mm; 1.2 mm; 1.3 mm; 1.4 mm; 1.5 mm; 1.6 mm; 1.7 mm; 1.8 mm; 1.9 mm; 2.0 mm; 2.1 mm; 2.2 mm; 2.3 mm; 2.4 mm; 2.5 mm; 2.6 mm; 2.7 mm; 2.8 mm; 2.9 mm; or 3.0 mm. In one embodiment, the HFs 34 have an inner diameter (Di) of about: 0.05 mm; 0.06 mm; 0.07 mm; 0.08 mm; 0.09 mm;0.1 mm; 0.2mm; 0.3mm; 0.4 mm; 0 5 mm; 0.6 mm; 0.7 mm; 0.8 mm; 0.9 mm; 1 mm; 1.1 mm; 1.1 mm; 1.2 mm; 1.3 mm; 1.4 mm; 1.5 mm. The size of the space between HFs (2007, Fig 19) will vary depending upon parameters of the process for which the HF panel 10 will be used, particularly the flow dynamic analysis (Reynolds number).

[000133] Fig. 19 depicts a cross section through the rows of HFs 34 and spacers 2014 that extend between the contact structures 906 in an intermediate phase during assembly. In this embodiment, a row 2010 comprising an odd number of HFs 34o alternates with a row 34e comprising an even number of HFs, the repetition of the rows thereby forming the hexagonal structures 2006. In one embodiment, the alternate rows of HFs 34o, 34e are separated along their length between contact structures 906 or 1006 by a spacer 2014. The spacer 2014 may be made of any stackable, nonstick, easily removable flat sheet of material. In one embodiment, the spacer 2014 comprises a material selected from the group consisting of laminated cardboard, polymeric material, wooden veneer, fiberglass sheet, sheet of paper, and combinations thereof. In one embodiment, the spacer 2014 comprises laminated cardboard.

[000134] Figs. 20-27 and 28A-28G illustrate suitable assemblies and processes for making the structures depicted in Figs. 18 and 19. The HF's may be provided in a variety of forms. Such forms include, but are not necessarily limited to rolls, spools, reels, or wrap beam assemblies. Fig. 28A is a side view of an embodiment in which a first roll 2050a comprises HF's having a first spacing (in one embodiment, an even number of HFs), and a second row 2050b comprising HFs having an alternating spacing (an odd number of HFs). In one embodiment, illustrated in Fig. 28B, the roll 2050a is sufficiently wide (line 2052) that a plurality of HF stacks 2054, 2054a are made using a single roll 2050a.

[000135] Fig. 28C is a perspective view of an assembly comprising a plurality of vertically adjacent spools 2052 of HFs arranged in rows. In one embodiment, horizontally adjacent spools are used (not shown). Fig. 28D is a schematic top view of an assembly comprising a first spool row 2052a comprising an even number of HFs alternating with a second spool row 2052b comprising an odd number of HFs. Fig. 28E is a perspective view of an assembly for manufacturing reels 2054 of HFs from a plurality of spools 2052. Fig. 28F is a schematic top view of an assembly comprising a plurality of adjacent reels 2060 of HFs which may be spaced, as required, to produce the alternating rows of odd and even HFs. Fig. 28G is a schematic view of a wrap beam assembly 2060 with the plurality of HFs 34 extended from therefrom, which also may be used in an assembly to make the membrane element.

[000136] In one embodiment, two or more loom heddles 2017 (Figs. 20 and 21) part alternating rows 34o, 34e of HFs (Fig. 19). The alternating rows of 34o, 34e of HFs may have a variety of arrangements. In one embodiment, the loom heddles 2017 part rows with an even number of HFs 34e alternating with rows comprising an odd number of HFs 34o. The process will be described in more detail in connection with a loom heddle. Persons of ordinary skill in the art will recognize how to use rolls, spools, reels, or wrap beam assemblies in a similar process.

[000137] In one embodiment, a HF assembly platform 2018 is provided adjacent to the HF loom heddle 2016. Referring to Fig. 21, in one embodiment, a first spacer 2014a is provided on the HP assembly platform 2018. In one embodiment, a first row comprising an odd number of spaced HFs 34o is extended lengthwise across the first spacer 2014a. In one embodiment, the opposed ends 2015 of HFs opposite to the loom heddle 2016 are weighted or engaged to maintain the HFs extended along the length of the HF assembly platform 2018. In one embodiment, the opposed ends 2015 of the HFs are weighted or engaged sufficiently to extend the HFs. In one embodiment, one or more of the opposed ends 2015 of the HFs are engaged by a suitable clamp (not shown). In one embodiment, the clamp is lined with an elastic material to reduce deformation of the HFs engaged in the clamp. [000138] The elastic material may be of natural origin, such as natural rubber or cork, or of synthetic origin, such as thermoplastic elastomers, including styrenic elastomers, polyolefins, polyurethanes, polyamides, and combinations thereof. In one embodiment the elastic material is thermoplastic elastomer including, but not necessarily limited to those selected from the group consisting of silicon elastomer, neoprene, isoprene, butyl rubber, polymer flexible foam, and combinations thereof. Generally, these elastic materials have a Young's Elasticity Modulus of less than lGPa and specific gravity of less than 1000 kg/m ³ . In one embodiment, the elastic material is rubber. In one embodiment, all of the opposed ends 2015 of the HFs are engaged in a single clamp having a suitable width and sufficient weight or tension to straighten the HF on the HF assembly platform 2018, but without stretching the HFs.

[000139] In one embodiment, a spacer 2014b is placed over the first row of HFs 34o. In one embodiment, a next row 34e comprising an even number of HFs is extended across the second spacer 2014b. Referring to Fig. 23, the process is repeated until a stack comprising the desired number of rows of HFs 34o, 34e (Fig. 19) is formed. The number of rows of HFs 34o, 34e will vary with the desired size of the contact structure 906 and with the outer diameter (D ₀ ) of the HFs 34. In one embodiment, the depth of the stack of rows of HFs (2027 in Fig. 23, 3005 in Fig. 29A) is 40 mm. In this embodiment, a stack comprising HFs having an outer diameter (D ₀ ) of 1 mm will comprise from about 36 to about 48 rows of HFs. Processes using HFs having a larger outer diameter (D ₀ ), for example of about 2 mm, will comprise about 16 to about 24 rows of HFs.

[000140] In one embodiment, HF stack depth (2027 in Fig. 23, 3005 in Fig. 29A) is 40 mm., the HFs have an outer diameter (D ₀ ) of less than 0.5 mm, and the stack comprises from about 64 to about 80 rows of HFs. Processes using HFs having a smaller diameter of 0.5 mm or less would include ISO power generation and reverse osmosis. In one embodiment, the stack comprises the following number of rows of HFs: 20 or more; 21 or more; 22 or more; 23 or more; 24 or more; 25 or more; 26 or more; 27 or more; 28 or more; 29 or more; 30 or more; 31 or more; 32 or more; 33 or more; 34 or more; 34 or more; 36 or more; 37 or more; 38 or more; 39 or more; 40 or more. In one embodiment, the stack comprises 30 or less rows of HFs. In one embodiment, where relatively small size HFs are used, the space 2007 (Fig. 19) between HFs may be at or slightly greater than the outer diameter (D ₀ ). This may require increasing the width 2003 (Fig. 18, 3008 in Fig. 29 A) of the contact structure and/or adding one or more HFs panels 10, as needed.

[000141] The stack may have any suitable HF stack depth (2027 in Fig. 23, 3005 in Fig. 29A). In one embodiment, the HF stack depth 2027, 3005 is about 30 mm or more; 35 mm or more; 40 mm or more; 45 mm or more; 50 mm or more; 55 mm or more; 60 mm or more; 65 mm or more; 70 mm or more. In one embodiment, the HF stack depth is 80 mm or less.

[000142] In one embodiment, the HF assembly platform 2018 (Fig. 20) has a width 2023 of from about 500 mm to about 3m or more, depending upon how many membrane elements are being made on the HF assembly platform. In one embodiment, the HF assembly platform 2018 has a width of about 500 mm or more; 600 mm or more; 700 mm or more; 800 mm or more; 900 mm or more; 1 m or more; 1.1 m or more; 1.2 m or more; 1.3 m or more; 1.4 m or more; 1.5 m or more; 1.6 m or more; 1.7 m or more; 1.8 m or more; 1.9 m or more; 2 m or more; 2.1 m or more; 2.2 m or more; 2.3 m or more; 2.4 m or more; 2.5 m or more; 2.6 m or more; 2.7 m or more; 2.8 m or more; 2.9 m or more; or 3 m or more. The HF assembly platform 2018 has a length of several times of its width. In one embodiment, the contact structure 906 of Fig. 29A has a length (2001, Fig. 18) of 3 meters or less. In one embodiment, the total stack depth 2027 (Fig. 23, 3005 of Fig. 29A) occupies about 75% of the width (2003, Fig. 18, 3010 in Fig. 29A) of the contact structure 906.

[000143] When aligned, the spacers 2014a, 2014b of Fig. 20 form a plurality of HF potting chambers 2020 a-d of Fig. 22 and 23 to form a plurality of HF panels 10 (Fig. 1). In one embodiment, referring to Fig. 27A, the spacers are simple, unattached sheets 2014a, 2014b. The sheets 2014a, 2014b may have a variety of shapes as long as they define the potting chambers (alone, or in combination with surrounding structures), provide adequate separation of the alternating rows of HFs 34o, 34e, and are easily removable. Referring to Fig. 25, each spacer 2014 comprises a sheet of material extending between opposed ends 2021a, 2021b and opposed longitudinal edges 2022a, 2022b. The potting chambers 2020a-2020d comprise slots through the spacers 2014 extending from the longitudinal edge 2022a to the opposed longitudinal edge 2022b. The distance between potting chambers 2020a and 2020b, or 2020c and 2020d, etc., form the desired length of HF in between these chambers. Each potting chamber 2020a-d will form a contact structure 906 (Fig. 26, Fig. 29A, Fig. 3D) or 1006 (Fig 3E). In one embodiment, the spacers 2014 are reusable durable sheets adapted to consistently produce potting chambers 2020a-d having predetermined dimensions.

[000144] In one embodiment, the spacer 2014 also comprises an intermediate slot 2026 of Figure 25 between potting chambers 2020a-2020d. The intermediate slot(s) 2026 divide the relatively long section of spacer 2013 between opposed potting chambers, e.g. 2020c and 2020d, into smaller sections for ease in later side removal of the spacer 2014.

[000145] Referring back to Fig. 23, when the spacers 2014 are placed between the layers of HFs, the slots align to form the potting chambers 2020a-2020d. The resulting potting chambers 2020a-2020d have well defined dimensions, orientation, careful alignment of HFs and relatively smooth internal surfaces. In one embodiment, referring to Fig. 24, an upper edge 2030b of each potting chamber fluidly communicates with a source of potting material 2000 (not shown). In one embodiment, a lower edge 2030a of each potting chamber may fluidly communicate with a source of potting material 2000.

[000146] In one embodiment, suitable provisions are made to prevent the potting material 2000 (Fig. 18) from filling unintended areas. In one embodiment, a petroleum based malleable sealant is applied to the surfaces of the potting chambers 2020a-2020d defined by the slots, including any gaps at the surfaces. In one embodiment, the petroleum based malleable sealant is smoothed using any suitable method to avoid damaging the HFs or the contact structure 906 during separation after curing the contact structure 906. In one embodiment, the petroleum based malleable sealant is smoothed using a brush or air stream. In one embodiment, the petroleum based malleable sealant is applied between HFs in spaces 2006, 2007 (Fig. 19) between HFs. In one embodiment, the petroleum based malleable sealant is applied to portions of spaces (2007, Fig. 19) adjacent to the contact structure 906 to a sufficient distance to prevent invasion of the potting material 2000 into the spaces 2007. In one embodiment, the petroleum based malleable sealant is petroleum jelly, preferably Vaseline. In one embodiment, a 10-15 mm layer of the petroleum based malleable sealant is applied around the inside of each potting structure 2020a-d. In one embodiment, the layer of petroleum based malleable sealant has a thickness on the surface of the contact structure (not shown) that is equivalent to the HF diameter (D ₀ ), or about: 0.5 mm or more; 1 mm or more; 2 mm or more; 3 mm or more. In one embodiment, the layer of petroleum based malleable sealant has a width of 15 mm or less. In one embodiment, the petroleum based malleable sealant is applied each time a new HF is strung across the potting chamber or applied when a spacer 2014 is placed.

[000147] In one embodiment, after all of the desired rows of HFs 34o, 34e and spacers 2014 are stacked, and after forming the potting chamber and trimming its rough edges, potting material is poured or injected into the chamber and subjected to setting conditions. In one embodiment, liquid epoxy resin of polymeric or semi- polymeric material is poured into the chamber and allowed to set for about an hour until the potting material solidifies. Thereafter, the spacers are removed.

[000148] Once material 2000 sets, the contact structures 906a, 906b (Fig. 26) are formed. In one embodiment, a plurality of membrane elements 3000 (Fig. 26, Fig. 29A) are formed adjacent to one another (see Fig. 28). In this embodiment, the membrane elements 3000 (Fig. 26, Fig. 29A) are separated. In one embodiment, the spacers 2014 are removed, leaving the membrane elements 3000 comprising the HF's 34 extending therebetween. In one embodiment, the portion of HF's 34 extending between adjacent potting chambers (e.g., between 2020b and 2020c in Figs. 22 and 23) is cut to produce the membrane element 3000 (Fig. 26, Fig. 29A). In one embodiment, the outer edges of the potting chambers are smoothed using industrial method. The result is membrane element 3000 comprising opposed contact structures 906a, 906b (Fig. 26).

[000149] The size of the HF panels 10 (Fig. 1) may vary depending upon a variety of factors. In one embodiment, typically in larger HF panels 10 of over 300 mm in length, intermediate baffles may be required to retain the position of HFs and to avoid damage to the HFs in relatively high turbulent flow, particularly during startup of operation. In one embodiment, the baffles 710, 720 (Fig. 3G) are made during the potting procedure. In this embodiment, referring to Fig. 27, the spacers 2014a, 2014b, 2014c are rectangular and spaced apart adjacent to one another across the HFs 34. Referring to Fig. 27A, when the spacers 2014a-2014c are stacked between the even layers of HFs 34e and the odd layers of HFs 34o, spacer potting chambers 2019 are formed. The spacer potting chambers 2019 have well defined dimensions, orientation, careful alignment of HFs and relatively smooth internal surfaces.

[000150] In one embodiment, suitable provisions are made to prevent the potting material 2000 (Fig. 18) from filling undesired areas. In one embodiment, a petroleum based malleable sealant is applied to the surfaces of the spacer potting chambers 2019, including any gaps at the surfaces. In one embodiment, the petroleum based malleable sealant is smoothed using any suitable method. In one embodiment, the petroleum based malleable sealant is applied in spaces surrounding the HFs 34 adjacent to the spacers 2014a-c to a sufficient distance to prevent invasion of the potting material 2000 into the spaces. In one embodiment, the petroleum based malleable sealant is applied each time a new HF is strung across the potting chamber.

[000151] In one embodiment, after all of the desired rows of HFs 34o, 34e and spacers 2014 and 2014a-c are stacked, the material 2000 is injected in fluid form into the spacer potting chambers 2019 (Fig. 27A) and exposed to curing conditions. Once material 2000 cures, the baffles 710 (Fig. 27B) are formed. In one embodiment, the spacers 2014a-c are removed. Fig. 27B is a cross section through Fig. 27 at line X-X. The baffles 710 extend through and retain the HFs in a plane defined by the baffles. The baffles 710 may have a variety of sizes depending upon the size of the HF panel 10. In one embodiment, the baffles 710 have a thickness D ₃ of from about 6.3 mm (1/4 inch) to about 0.375 mm (3/8 inch). In one embodiment, adjacent ends of the baffles 710 are glued to adjacent sides of HF frame (19, 19a, Fig. 1).

[000152] Accordingly, in one embodiment, the application provides a method of making a membrane element, the method comprising:

a. providing a plurality of detachable spacer structures having given

dimensions;

b. placing one or more first spacer structures on an HF assembly

platform;

c. extending a first row of first HFs with first spaces therebetween over the one or more first spacer structures aligned with the longitudinal axis of the HF assembly platform, forming a first longitudinal row of first HFs, the first spaces having a width effective according to flow dynamic calculations to maintain turbulence flow across and along surfaces of the hollow fiber membranes at a Reynolds Number of 3,000 or more;

d. placing one or more second spacer structures having the given

dimensions over the first row of HFs aligned with the one or more first spacer structures;

e. extending an adjacent row of HFs with second spaces therebetween across the one or more second spacer structures aligned with the longitudinal axis of the HF assembly platform;

f. repeating (d)-(e) with additional rows of HFs and spacer structures, forming a stack of alternating rows of HFs and intervening spacer structures, the stack having a desired height, wherein vertically aligned adjacent surfaces of the stacked spacer structures define potting chambers at opposed ends of the HFs, the potting chambers defining an inner surface having predetermined dimensions.

[000153] In one embodiment, the method comprises:

g. applying a malleable sealant over the inner surface of the potting

chambers, producing sealed potting chambers;

h. injecting thermosetting material into the sealed potting chambers; i. curing the thermosetting potting material, thereby forming a plurality of contact structures comprising HFs extending therebetween; and, j. removing the intervening spacer structures.

[000154] In one embodiment, referring back to Fig. 3E, the header comprises a solid structure 1000 with a bore 1008 therethrough. The solid structure 1000 may have a variety of shapes. Suitable shapes include, but are not necessarily limited to, triangular shapes, rectangular shapes, pentagonal shapes, hexagonal shapes, cylindrical shapes, oblong shapes, and the like. In one embodiment, the solid structure 1000 is an elongated rectangular structure. The bore 1008 also may have a variety of shapes. In one embodiment, depicted in Fig. 3E, the solid structure 1000 is an elongated rectangular structure with an elongated cylindrical bore 1008

therethrough.

[000155] The solid structure 1000 may be made of any suitable material. In one embodiment, the solid structure 1000 is made of steel. In one embodiment, the steel is coated with a suitable corrosion protection material. Substantially any corrosion protection material may be used. In one embodiment, the corrosion protection material is Teflon. In one embodiment, the corrosion protection material is epoxy. In one embodiment, the solid structure 1000 is made of fiber reinforced plastic. In one embodiment, a portion of a side of the solid structure comprises a contact structure 1006 adapted to retain the plurality of HFs 14 in a loosely packed arrangement. The contact structure 1006 may be any suitable material. In one embodiment, the contact structure 1006 comprises a suitable thermosetting material. In one embodiment, the contact structure 1006 is selected from the group consisting of epoxy, polyurethane, and combinations thereof. As seen in Fig. 3D, the ends 13 (Fig. 1A) of the hollow fibers 34 empty into the pipe structure (904 in Fig. 3D, 1000 in Fig. 3E).

[000156] Figure 3F is a cross section taken at line 3F-3F of Fig. 2. Figure 3F is a cutaway/transparent frame perspective view of a HF panel 10 (Fig. 2) comprising the header 16 and an adjacent header 26 (Fig. 2). In Fig. 3F, the header 16 is a solid rectangular structure 902 comprising a pipe or bore 904 therethrough. The header 26 comprises a solid rectangular structure comprising a pipe or bore 913 therethough. As seen in Figure 3F, process fluid travels from a header terminal box 16aa, through the pipe 904 and across the header 16 (Fig. 2) to an opposed header terminal box 16aa'. The process fluid entering the header terminal box 16aa' passes through the aperture 23 into the header terminal box 26aa of the header 26 and enters the pipe 913. The process is repeated for additional adjacent panels.

[000157] Leakage from adjacent header terminal boxes, such as 26aa' and 16aa' in Fig. 3F, similarly may be avoided using a variety of suitable sealing arrangements. For example, in one embodiment, a cylindrical sleeve (not shown) may extend through the adjacent apertures 23, 23a (Fig. 3F) and sealingly engage adjacent inside surfaces in each header terminal box. The sealing engagement may be fixed or flexible. In one embodiment, the sealing engagement is provided using o-rings between the outer surface of the sleeve and adjacent surfaces in the respective header terminal box. In one embodiment, adjacent frame surfaces are sealed to retain the feed flowing between the plurality of HFs and prevent high pressure feed flow escaping from the array. In one embodiment, adjacent frame surfaces are provided with sealing gaskets.

[000158] Fig. 6 is a cross section through an array comprising a square array casing 60. A rectangular or square array casing 60 may be used in a variety of circumstances. In one embodiment, a square array casing 60 is used where the pressure of the process fluid 62 inside the HF lumens is relatively high and the pressure of the feed is relatively low.

High pressure cells

[000159] In one embodiment, the array or a plurality of arrays are retained in a suitable pressure vessel. Suitable pressure vessels comprise an outer wall defining an interior having a cross section with a variety of configurations, including but not necessarily limited to a triangular configuration, a circular configuration, an elliptical configuration, and a rectangular configuration. In order to support the array of the present application within a pressure vessel, it is desirable to have two or more contact points between the outer surface of the array and the interior of the pressure vessel.

[000160] In one embodiment, high pressure cells are provided by placing the array or a plurality of arrays in a suitable pressure vessel. Suitable pressure vessels comprise an outer wall defining in interior having a cross section with a variety of configurations, including but not necessary limited to a triangular configuration, a circular configuration, an elliptical configuration, and a rectangular configuration.

[000161] In one embodiment, referring to Figure 7, the pressure vessel 70 is circular in cross section. This embodiment provides four contact points 74a-74d between the inside wall of the pressure vessel 70 and corners of the array. These contact points 74a-74d support the array 30 within the pressure vessel. In one embodiment, the array 30 is provided with a sealing encasement 71 therearound. The sealing encasement may be any suitable sealant material effective to maintain a specified turbulence flow rate at the given feed operating pressure. In one embodiment, the encasement is shrink wrap or polypropylene. In one embodiment, one or more additional supports 76a-76d extend from a surface of the array casing to the interior of the pressure vessel, providing additional support. In this embodiment, there is a relatively large fluid flow area between (70a) between the interior of the pressure vessel and the array casing. The sealing encasement 71 is effective to prevent leakage or seeping of the high pressure relatively unprocessed raw feed (37, Fig. 3) to the processed feed flowing through the HF array (37a, Fig. 3) at relatively lower operating pressures. This embodiment is useful under a variety of conditions. In one embodiment, a circular or elliptical pressure vessel is useful with a relatively high pressure process fluid inside of the HFs and a relatively low pressure feed.

[000162] The pressure vessel also may comprise a plurality of segments having progressively changing diameters, a plurality of pressure vessels having progressively changing diameters, and a combination thereof.

[000163] Figure 11 illustrates a cell comprising a single pressure vessel 80 in fluid communication with a first pump 84 and a second pump 81. The pressure vessel 80 comprises segments 82a - 82d having progressively decreasing diameters, respectively. The segments 82a-82d contain an exchanger 88 comprising a plurality of arrays 87a-87d that also have progressively decreasing diameters. In one embodiment, the changing diameter and size accommodates variability of flow pattern and capacity inside the HFs and across the exchanger.

[000164] The first pump 84 fluidly communicates with a source (not shown) of high salinity brine. In one embodiment, the source is a brine evaporation lake. The high salinity brine is pumped from the source through a filter 83 effective to remove solid material, producing a pressurized initial brine feed 85.

[000165] The pressurized initial brine feed 85 travels around an outer perimeter of the exchanger 88 from a relatively large segment 87a to a smallest segment 82d. An initial brine feed 85a enters the smallest diameter array 87d. The initial brine feed 85a enters an open end 88a of the array 88 and flows across an initial array 87d having a smallest diameter which is contained in a segment 82d of the pressure vessel 80 that has a smallest diameter. The flow within the array is similar to that described in Figure 3. As a result of the exchange with fluid inside hollow fiber lumens, an initial modified feed 85b has a lower salinity, a higher flow rate, and a slightly lower pressure than the initial feed 85a. The initial modified feed 85b is fed to an adjacent array 87c having a larger diameter than the initial array 87d contained in an adjacent segment 82c of the pressure vessel 80 that has a larger diameter than the initial segment 82d. The adjacent array 87c produces a second modified feed 85c having a lower salinity, a higher flow rate, and a slightly lower pressure than the initial modified feed 85b.

[000166] The second modified feed 85c flows into an adjacent array 87b having a larger diameter than the adjacent array 87c and contained in an adjacent segment 82b having a larger diameter than adjacent segment 82c. The adjacent array 87b produces a third modified feed 85d having a lower salinity, a higher flow rate, and a lower pressure than the second treated feed 85c.

[000167] The third modified feed 85d flows into an adjacent array 87a having a larger diameter than the adjacent array 87b and contained in an adjacent larger segment 82a of the pressure vessel 80 having a larger diameter than adjacent segment 82b. The adjacent array 87a produces a final modified feed 89 having a lower salinity, a higher flow rate, and a lower pressure than the third modified feed 85d. The conditions are optimized to achieve system overall projected efficiency. In one embodiment, the conditions are optimized to minimize the overall pressure drop across the exchanger 88. In one embodiment, the conditions are optimized to maintain an overall pressure drop across the exchanger 88 of about 1 bar (15 psi) or less.

[000168] The final modified feed 89, comprising a diluted brine, is pumped to a turbine 86 at a relatively high pressure to produce electricity. In one embodiment, a relatively low pressure turbine discharge comprising diluted brine is recycled to the source (not shown). In one embodiment, the source is an evaporation lake.

[000169] Water or relatively low salinity brine is fed as process fluid to the plurality of HFs 14 in the array 88. In the embodiment of Fig. 11, diluted brine 91 discharged from a turbine 95 of a prior cell 93 is fed from a turbine discharge drum 95a as process fluid to an initial panel 97 of the adjacent array 87a. The process fluid flows through the HFs of the initial panel 97 and through the HFs of successive panels to a tail panel 97a. In one embodiment, the initial array 87d comprises the tail panel 97a. As the lower salinity process fluid flows across the HFs from the initial panel 97 to the tail panel 97a, a tie-line of water flows from the lower salinity process fluid 91 in the HFs 14 into the higher salinity feed 85a. In one embodiment, the lower salinity process fluid 91 has a relatively low pressure. In one embodiment, the lower salinity process fluid 91 has a pressure of from about 1 to 2 bars. The result is a concentrated process fluid 91a. In one embodiment, the concentrated process fluid 91a is fed as a relatively high salinity brine feed to a different cell of a multi-cell power plant. In one embodiment, the concentrated process fluid 91a is fed as a high salinity brine feed to a prior cell of a multi-cell power plant.

[000170] In one embodiment, the array 88 is surrounded by an array casing 88a. In one embodiment, array casing 88a comprises an open tail end 88b. In one embodiment, the initial feed 85a flows into the array 88 at the open end 88a at a given pressure. In one embodiment, the diameters of the segments 82a-d of the array casing 88a maintain the pressure of the feed sufficiently high to flow across the array 88. In one embodiment, the diameters of the segments 82a-d are effective to maintain the pressure drop from the feed 85 entry point to feed 85 a entry point of less than 1 bar.

[000171] In one embodiment, the system operates in a countercurrent diminishing flow. Operating in countercurrent diminishing flow has the advantage of enhancing water permeation across the semipermeable membranes, causing proportional changes in flow and concentration outside and within each hollow fiber.

[000172] In one embodiment, referring to Fig. 14, the adjacent arrays lOOa-lOOd fluidly communicate via flexible conduits 102a-c, respectively. In this embodiment, referring to Fig. 14A, the corners of the array 112-112d do not fixedly communicate with the interior of the pressure vessel 106. In one embodiment, the adjacent arrays lOOa-lOOd flexibly communicate with the pressure vessel. In one embodiment, the exchanger comprises support members selected from the group consisting of electromagnetic vibrators, spring supports, HF encasement supports, and combinations thereof. Figure 14a is a cross section at 14a-14a' in Figure 14. Fig. 14a depicts opposed electromagnetic vibrators 104a and 104b. In one embodiment, the electromagnetic vibrators 104a and 104b provide further control of fouling. In one embodiment, the electromagnetic vibrators 104a and 104b also provide further control of concentration polarization. In one embodiment, depicted in Figure 14A, spring supports 108 and 108a are provided at intervals along the length of the exchanger. In one embodiment, support members 110, 110a are provided at intervals along the length of the exchanger. [000173] Figure 11 A illustrates an induced symbiotic osmosis power generation train comprising 3 cells, forming low pressure exchanger section 370, and a high pressure exchanger section 372. The low pressure exchanger section 370 comprises two sequential segmented exchangers comprising a first segmented exchanger 374 and a second segmented exchanger 376 of a design described in Fig. 8, with a cross section similar to Fig. 6. These exchangers 374, 376 have generally low operating pressure of 5 bars or less, with a HF lumen pressure (process fluid pressure) that is higher than its external pressure (feed pressure). Exchangers are limited in size- typically having diameters or 4 meters or less for cylindrical pressure vessels and 12 square meters or less for rectangular low pressure HF membrane housing.

[000174] The high pressure exchanger section 372 comprises a HF exchanger having two identical exchangers 378, 380, where each exchanger comprises a design described in Fig. 11, with a cross section similar to Fig. 7. These exchangers 378, 380 have high operating pressure of 30 bars or more, with HF external pressure (feed pressure) that is much greater than HF lumen pressure (process fluid pressure).

[000175] The train of exchangers of Fig. 11A operates within a water salinity field, ranging from a no or low salt water supply on one side of the train 392 to a high salinity water supply 390 reaching saturation on the other side of the train. This implies that water of essentially salt free content diffuses osmotically from the low salinity side of the train to the high salinity side of said train.

[000176] This also implies that process embodiments of specific design have to be provided to allow for stable and continuous osmotic transfer of essentially water- free salt from a source of low salinity water 392 on one side of the train to a source of high salinity water 390 on the other side of the train at a constant rate, here is called "The Tie Line". See also U.S. Patent No. 8,545,701.

[000177] This Tie Line flow is proportional to the flow of the high salinity water supply 390 (or the feed flow rate). The ratio of Tie line flow to the high salinity water flow (feed flow rate) generally varies between 1 and 7 depending the salt

concentration of the source of high salinity water 390 to the train and determines the size of operating system.

[000178] Initially, each cell is be charged with salt solution of a specific concentration, where the salt concentration in each cell increases stepwise from the cell at a low salinity side 392 to the cell at high salinity side 390 of the train, in accordance with the train operating and design objectives.

[000179] Commissioning of such a train, could be accomplished in phases, preferably starting with Cell 1, then gradually engaging the other cells. As steady state operation is reached, all rotating equipment of the train: pumps (PI, P2, P3, and P4), turbines (Tl, T2, and T3) and control systems (not shown) will be operating simultaneously, continuously and rhythmically to maintain a continuous and steady Tie Line flow through the train.

[000180] The operating scheme of the train may comprise the following steps. Fresh water or seawater is pumped at relatively low pressure by means of PI via feed 392 through the low pressure shell side of HF exchanger 374 external to the hollow fiber, while relatively higher salinity water is pumped at relatively high pressure by means of P2 via stream 399 through the relatively high pressure HF lumens of exchanger 374.

[000181] As a result, osmotic potential across the HF membrane interface is enhanced and a substantially salt-free Tie Line defuses into the HF membrane pores and into the process fluid in the lumens. The diffusion dilutes the concentration of the process fluid and produces a large increase in process fluid volume, and forming existing stream 396b, which has a volumetric capacity of twice or more than that of the entering stream 399 essentially at an equivalent pressure (relatively low pressure drop through the exchanger). The flow of stream 396b generates power by means of hydraulic turbine Tl. The power produced at Tl exceeds the pumping power requirement of the train, generating excess power of commercial value. In the meantime, stream 392 is gradually depleted and its salt concentration is gradually increased to form stream 395.

[000182] Cell 2 operates in a similar fashion as Cell 1, but at relatively higher salinity conditions and higher pressure. Here, feed stream 396a enters the low pressure shell side of HF exchanger 376 external to the hollow fiber, while relatively higher salinity water (process fluid) is pumped at relatively high pressure by means of P3 via stream 391 through the relatively high pressure HF lumens of exchanger 376.

[000183] As a result, osmotic potential across the HF membrane interface is enhanced, and a substantially salt-free Tie Line defuses into the HF membrane pores and into the process fluid in the lumens. The diffusion dilutes the concentration of the process fluid and produces a large increase in process fluid volume, and forming existing stream 398. Stream 398 has a volumetric capacity of twice or more than that of the entering stream 391 essentially at an equivalent pressure (relatively low pressure drop through the exchanger). The flow of stream 398 generates power by means of hydraulic turbine T2 that exceeds the pumping power requirement of the train, generating excess power of commercial value. In the meantime stream 396 b flow is gradually depleted and its salt concentration is gradually increased forming stream 399, where it can be recycled as a high salinity feed to HF exchanger 374.

[000184] The third cell comprises two high operating HF pressure vessel exchangers 378, 380 of a design described in Fig. 11 and 13 with cross sections similar to Fig. 7. Here, stream 398b leaving turbine T2 enters each high pressure HF exchanger 378, 380 comprising two identical high pressure sections, each section comprising high pressure encased HF arrays with a cross section similar to Fig. 7. Receiving drums 382, 382a are provided to stabilize flow rate at each exchanger 378, 380.

[000185] In this embodiment, the feed 383a to HF exchangers 378, 380 operates at a pressure of 30 bars or more, while the process fluid in the HF lumens operates at a low pressure of 5 bars or less. In one embodiment, high salinity brine potentially approaching saturation (35% in case of sodium chloride) is pumped with high pressure pump P4 as a feed brine 383a from an evaporation /concentration pond 390, through the four pressure vessel segments surrounding the encased hollow fiber arrays as shown in Figs.7 and 14A. To ensure effective engagement of water flow with the HF membranes, the brine feed flows around the outside the HF arrays 383b to the end of each exchanger 381, 381a, where the flow direction reverses and enters the encased HF arrays at 381 and 381a to effectively engage the full surface of the HF arrays in a cross flow pattern.

[000186] Meanwhile, the low pressure diluted stream 398b exiting the turbine T2 (398a) is circulated to enter the HF lumens of the high pressure exchangers 378 and 380 of Cell 3. This results in enhancing osmotic potential across the HF membrane interface and allowing essentially salt-free water to diffuse from inside the HF lumen across membrane pores, to form stream 396, resulting in maintaining the Tie Line flow of the Cell 1 and Cell 2 and causing dilution of the brine feed 383a.

[000187] This also will result in a large increase in flow of the process fluid, forming an existing stream 396 that has volumetric capacity of twice or more than that of the entering streams 382, 382a and essentially at an equivalent pressure (relatively low pressure drop through the exchanger) allowing generating power by means of hydraulic turbine T3 that exceeds the pumping power requirement of the train by means of P4, generating excess power of commercial value. Meanwhile,

concentrating stream 398 that now can be returned to Cell 2 as stream 391.

[000188] Using freshwater or sweater to supply the first cell of the train is essentially dependent on availability of each source and the cost to supply it.

Freshwater is always preferable for its better efficiency and low cost of treatment. However, seawater is abundant, but a large volume is required to extract the salt-free water that is needed to run the HF train.

[000189] Figure 12 is a top view of a final two cells 600 in a power train comprising a plurality of cells 602, 602a comprising substantially the structure depicted in Fig. 11. In Figure 12, the relatively low pressure discharge 604 from a prior cell (not shown), and discharge 604a from the hydro-turbine of adjacent cell 605, respectively, are charged as process fluid 609a, 609b to the HFs of a respective subsequent cell. In one embodiment, a final low pressure discharge 604b from the hydro-turbine 603 of a final cell 602a is fed to a brine making source 606. In one embodiment, the brine making source 606 is a brine making evaporation lake. In one embodiment, the brine making source 606 is the source of the feed 601 to the adjacent cell 605.

[000190] Figure 13 illustrates a final cell 120 of an ISO power generation exchanger, the cell 120 comprising multiple pressure vessels 122, 124, 126 having the structure generally described in Figure 11.

[000191] In one embodiment, the multiple pressure vessels 122, 124, 126 (Fig. 13) do not comprise flexible support members. In one embodiment, the multiple pressure vessels 122, 124, 126 (Fig. 13) do comprise flexible support members, described more fully in connection with Fig. 14. [000192] Referring again to Fig. 13, diluted brine 128 discharged from the turbine of a prior cell is fed as process fluid to initial panels 130, 132, 134 of the exchangers in the respective pressure vessels 122, 124, 126. In one embodiment, the diluted brine 128 has a relatively low pressure. A high salinity brine feed 135 is fed from a source 140 into each pressure vessel 122, 124, 126 at 131a-c. In one embodiment, the high salinity brine feed 135 has a relatively high pressure. As it passes across the exchanger, water permeates from the process fluid 128 into and dilutes the high salinity brine feed 135. The result is a diluted brine product 138. In one embodiment, the diluted brine product 138 is fed to a turbine 141. In one embodiment, a turbine discharge 141a is recycled to the source 140 of high salinity brine. The process fluid 128 is progressively concentrated as it passes from the initial panels 130, 132, 134 to the tail panels 137a-c. The resulting concentrated process fluid 136a, 136b, 136c is discharged from the respective tail panels 137a-c. In one embodiment, the concentrated process fluid 136a, 136b, 136c is charged as brine feed to one or more prior cells.

Operating pressures/tie-line and flow rate

[000193] In large systems, the tie-line flow rate is expressed in units of cubic meter per second (mVs). For small or closed systems, the tie-line flow rate is expressed in units of liter per second (L/s). One unit of L/s high salinity brine feed will generate from about 20 to about 50 KW of power using the present system. If the Log Mean Concentration Difference (LMCD, defined below) is larger than the allowable operating pressure of the membrane, a large amount of the chemical potential of the system is wasted, resulting in a lower efficiency. Accordingly, the salinity of the feed to the last cell should be as close to the salinity that produces the maximum operating pressure of the semipermeable membrane as possible.

[000194] The Tie-Line (TL) flow rate is determined by the ratio (X) of (a) salinity of the feed to a last cell in a train of cells (hereafter the "last cell feed salinity") to (b) the salinity of fluid discharged from the last cell in the train of cells (hereafter the "last cell discharge salinity"),

where;

X= (last cell feed salinity/last cell discharge salinity) = (last cell discharge volumetric flow rate/last cell feed volumetric flow rate - 1)

[000195] Assuming a last cell feed volumetric flow rate of one unit of volume (liter/second, or cubic meter/second, etc.), then:

TL=(last cell discharge volumetric flow rate/last cell feed volumetric flow rate) = X-l

In one embodiment, in a train comprising a plurality of cells, the ratio X and the TL is kept constant throughout the train. For example, if the last cell discharge salinity is 6% and X is 2 (the discharge volumetric flow rate is twice the last cell feed volumetric flow rate), then the TL is one unit of volume.

[000196] In one embodiment, the TL is optimized and the efficiency of power generation is optimized by evaluating salinity distribution across adjacent cells in the train.

[000197] Assume, for example, in one embodiment, that the allowable operating pressure of the semipermeable membrane is 6%. If the salinity of the feed to the last cell in a train is 12%, and the process fluid is freshwater, then the estimated LMCD is 8.66. Since 8.66 is higher than the allowable operating pressure of the membrane (6%), using 6% salinity as a basis for pump operation would not be efficient and valuable salinity would be lost. In one embodiment, the system is optimized to produce a final salinity within the allowable operating pressure of the membrane (6%) by adding an intermediate cell operating between 8 % and 4% salinity (ratio X = 2).

[000198] Assume, for example, in another embodiment: (a) that the allowable operating pressure of the semipermeable membrane is 6%; (b) that the available feed to the last cell in a train is 1 m ³ /s at 30% salinity; and, (c) that the process fluid is freshwater. In this embodiment, a final salinity of 6% is produced if X is 5 and the TL is 4 m ³ /s. Even greater efficiency can be realized by considering the LMCD of each cell in the train. In a train having only two cells, the LMCD of each cell would be 7.45— which is greater than the 6% allowable operating pressure of the semipermeable membrane. In one embodiment, greater efficiency is realized by using three ISO cells having the following salinity ranges: [10% -2%] _ce n i, [20% -4%] _{cell 2} , [30% -6%] _C eii 3, with a constant tie line flow of 4 m ³ /s. [000199] Optimization of ISO power trains becomes more complicated when the source of Tie-Line flow is brackish or seawater, due to the lower salinity operating margin available; between 3.5% and 6%.

[000200] High solubility salts are advantageous in ISO power generation. Formulated low molecular weight soluble salts are of significant value in the construction of self-sustained multi-cell high efficiency closed systems. Solubility of these salts can exceed 700 grams per liter (more than twice sodium chloride saturation). These ISO power systems rely on concentrated solar energy in arid areas of the world, including the sun belt of US. Such systems typically are composed of up to 7 cells with Tie-Line to brine feed flow ratio of 3-10.

[000201] Persons of ordinary skill in the art will recognize that an exchanger may comprise variety of numbers of arrays, and that a pressure vessel may have a variety of corresponding segments.

Integrated Large Scale ISO-DESAL Plant

[000202] Figure 15 is a top view of an integrated large scale ISO power and seawater desalination plant 200 comprising a power train 202. In one embodiment, the desalination cell 250 is operated using power produced by the ISO power train 202.

[000203] Referring to Fig. 15, a power train 202 comprises a plurality of cells 204a, 204b. In one embodiment, at least some of the cells 204b comprise multiple pressure vessels 206a, 206b, 206c, 206d comprising progressively differing diameters. In one embodiment, each pressure vessel 206a, 206b, 206c, and 206d retains an array 260a, 260b, 260c, and 260d

[000204] In one embodiment, seawater 252 is fed through a filter 254. Seawater 252 typically has a relatively low salinity of about 3.5 % (35 g/L, or 599 millimoles/liter). In one embodiment, filtered seawater is fed to one or more desalination cell (not shown). In one embodiment, a first filtered seawater 252a is fed to a desalination cell 250 comprising an array 251 adapted for reverse osmosis. Desalination using pairs of HF panels 10, 20 (Fig. 2) requires the use of higher pressures. In one embodiment, the first filtered seawater 252a is fed to a pressure exchanger 261. In one embodiment, the desalination feed 252b to the desalination cell 250 is a pressurized first filtered seawater. In one embodiment, the desalination feed 252b has a pressure of about 50 bars or more. In Figure 15, the desalination feed 252b travels around the desalination array 251 and across the panel 256 into the array 251. The desalination feed 252b travels from and across the panel 256 across the array 251 and across the panel 256a. As the desalination feed 252b flows under relatively high pressure across the array comprising HFs, water permeates from the seawater into the HFs, becoming a desalination product 255. The salinity of the desalination feed 252b increases as it passes from and across the panel 256 to and across the initial panel 256a. The result is salinated seawater 257. In one embodiment, the pressure exchanger 261 is adapted to use the high pressure of the salinated seawater 257 to conserve energy.

[000205] The desalination product 255 may be used in a variety of ways. In one embodiment, the desalinated product 255 is used as freshwater. In one embodiment, the desalinated product 255 is charged as process fluid to the power train. In one embodiment, the desalinated product 255 is used for both of the foregoing purposes.

[000206] In one embodiment, the salinated seawater 257 has a salinity of about 5% or more. In one embodiment, the salinated seawater 257 has a salinity of about 6% or more. In one embodiment, the salinated seawater 257 has a salinity of about 7 % or more. In one embodiment, the salinated seawater 257 has a salinity of about 8 % or less.

[000207] In one embodiment, the salinated seawater 257 has a salinity of from 4% to 7%. In one embodiment, the salinated seawater 257 has a salinity of from 5% to 7%. In one embodiment, the salinated seawater 257 has a salinity of from 6% to 7%. In one embodiment, the salinated seawater 257 has salinity 4% or more. In one embodiment, the salinated seawater 257 has a salinity of 5% or more. In one embodiment, the salinated seawater 257 has a salinity of 6% or more. In one embodiment, the salinated seawater 257 has a salinity of 7% or more.

[000208] This salinated seawater 257 may be used to complement the product brine 228d entering the source 245, thereby providing a potential for more power generation. In one embodiment, a brine combination 243 comprising the salinated seawater 257 and the product brine 228d is charged to a brine evaporation lake 245. In one embodiment, the brine combination 243 enters a first end 245a of the evaporation lake. The brine combination 243 is evaporated to as high a salinity as possible. In one embodiment, the brine evaporation lake 245 has a relatively lower salinity at the first end 245a, increasing to a relatively higher salinity source brine 245b at an opposed end. In one embodiment, the relatively higher salinity of the source brine 245b is still sufficiently low to be processed by semipermeable membranes of the HFs.

[000209] In one embodiment, the source brine 245b has a salinity about 8% or more. In one embodiment, the source brine 245b has a salinity of about 9% or more. In one embodiment, the source brine 245b has a salinity of about 10% or more. In one embodiment, the source brine 245b has a salinity of about 11% or more. In one embodiment, the source brine 245b has a salinity of about 12% or more. In one embodiment, the source brine 245b has a salinity of about 15% or more. In one embodiment, the source brine 245b has a salinity of about 20% or more. In one embodiment, the source brine 245b has a salinity of about 25% or more. In one embodiment, the source brine 245b has a salinity of about 30% or more. In one embodiment, the source brine 245b has a salinity of about 32% or less.

[000210] In one embodiment, illustrated in Fig. 15, the cell 204b comprises four pressure vessels. In one embodiment, the pressure vessel 206a has smaller diameter than pressure vessel 206b; the pressure vessel 206b has a smaller diameter than pressure vessel 206c; and, the pressure vessel 206c has a smaller diameter than the pressure vessel 206d.

[000211] In one embodiment, source brine 245b is introduced at 208 into a largest pressure vessel 206d. In one embodiment, the source brine 245b introduced at 208 flows around the array 260a, producing a bypass flow 230. The bypass flow 230 is introduced into the pressure vessel 206c and circulates around the array 260b producing a bypass flow 230a. The bypass flow 230a is introduced into the pressure vessel 206b and circulates around the array 260c, producing an initial feed 230b to the pressure vessel 206a. The initial feed 230b circulates around the array 260d in the pressure vessel 206a and across the tail panel 224a and to an initial panel 224 of the array 260d. As it passes across the array 260d, the initial feed 230b is diluted. In one embodiment, the diluted initial feed is a feed 228a to the array 260c in the pressure vessel 206b. In one embodiment, the feed 228a travels from and across a tail panel 222a to the initial panel 222 in the array 260c The feed 228a is diluted as it passes across the array from and across the tail panel 222a to and across the initial panel 222, producing a diluted feed 228b. In one embodiment, the diluted feed 228b is fed to the array 260b and travels across a tail panel 220a to an initial panel 220, producing a diluted feed 228c. In one embodiment, the diluted feed 228c is a fed to the array 260a in pressure vessel 206d. In one embodiment, the diluted feed 228c flows through and across a tail panel 214a to an initial panel 214, producing a diluted product 228d. In one embodiment, the diluted product 228d is fed to the turbine 242 to produce electricity and a reduced pressure turbine discharge. In one embodiment, the reduced pressure turbine discharge is blended with the salinated seawater 257 to produce the brine combination 243.

[000212] In one embodiment, the turbine discharge 216 of a prior cell 204a is used as process fluid 212. In one embodiment, the process fluid 212 is fed from a turbine discharge drum 212a to an initial panel 214 of the array 260a in the largest pressure vessel 206d. The process fluid 212 flows from the initial panel 214a to a tail panel 214 of the exchanger in the largest pressure vessel 206d. The result is a first concentrated process fluid 226.

[000213] The first concentrated process fluid 226 is fed into the HFs of an initial panel 220 of the array 260a in the pressure vessel 206c as process fluid. The process fluid 226 flows through the HFs in the initial panel 220 to and through the HFs in the tail panel 220a of the array, producing a second concentrated process fluid 226a. The second concentrated process fluid 226a is fed to the HFs in an initial panel 222 of pressure vessel 206b. In one embodiment, the second concentrated process fluid 226a flows through the HFs in the initial panel 222 to and through the HFs in the tail panel 222a, producing a third concentrated process fluid 226b. The third concentrated process fluid 226b is fed to the HFs in an initial panel 224 to and through the HFs in the tail panel 224a. The result is a final concentrated process fluid 240. In one embodiment, the final concentrated process fluid 240 is fed to prior cell(s) in the power train.

Water-extraction / water- recovery system

[000214] In one embodiment, the HF panels 10 are used in a system and process for water-extraction/water-recovery. Water-extraction/water-recovery may be important in a variety of situations. Such situations include, but are not necessarily limited to dialysis (removing water containing waste from blood in case of renal failure), recovering water from brine comprising one or more soluble salt, extracting water from an organic solution, and extracting water from a solution comprising radioactive contamination.

[000215] Solutes having lower molecular weights generally produce solutions having a higher osmotic pressure. Solutes having higher molecular weights generally produce solutions having a lower osmotic pressure. Accordingly, it is generally more efficient to extract water from solutions having relatively low osmotic pressure.

[000216] Flow rates during water-extraction/water-recovery generally are lower than flow rates during power generation. In one embodiment, flow rates during water extraction/water-recovery are in liter/sec, m ³ /min or gallon/min. In large scale systems for water extraction, the flow rate may be m ³ /sec.

[000217] In one embodiment, the HF panels are used to perform dialysis. In this embodiment, the HF membrane is a microfiltration membrane having a pore size range of from 0.1 to 10 micrometers. In this embodiment, the flow rate typically will be in cc/min.

[000218] In one embodiment, the HF panels are used in a system to recover water from brine (an aqueous solution comprising one or more soluble salts). In this embodiment, the HF panels comprise membranes of nanometer pore size, preferably less than 1 nanometer. In one embodiment, the HF panels are used to extract water from a feed comprising relatively low salinity brine. In one embodiment, the HF panels are used to extract water from a feed comprising 1% sodium chloride brine, which has an osmotic pressure of about 112 psi, using a process fluid comprising a 4% brine having an osmotic pressure of about 448 psi. In this embodiment, the permeate across the membrane (or tie-line) is one unit volume. Accordingly: 2 volumes of feed at 1% salinity leaves as 1 volume of permeate and 1 volume of concentrated feed at 2% salinity; and, 1 volume of process fluid at 4% salinity leaves as 2 volumes of diluted process fluid comprising the one volume of permeate, the diluted process fluid having 2% salinity. In this embodiment, the driving osmotic force (LMCD) is 162 psi. [000219] In one embodiment, water is extracted from an organic solution. In one embodiment, water is extracted from sugarcane juice containing 10% sugar. In one embodiment, the process fluid is 4% salinity brine. In food processing application, extraction process could be the only required process, without the need for further treatment. The osmotic pressure of the sugar solution is only about 10% of the osmotic pressure of the sodium chloride solution. Accordingly, in one embodiment: 2 volumes of feed comprising a sugar solution entering at a sugar concentration of 10% would produce 1 volume of permeate (tie line) and 1.0 volume of concentrated feed having a sugar concentration of 20%. In one embodiment, 10 volumes of feed comprising a 1% sugar concentration would produce 1.0 volume of concentrated feed having a sugar concentration of 20%. In this case, since the solution is very diluted and contains food grade product, it would be economically prudent to use an invasive process such as reverse osmosis, as the first heatless concentration process, to concentrate the solution to 20% concentration, then followed by an extraction process to reach higher concentrations, which may require process feed at 6 % salinity or higher. Extracted saline water might be concentrated with available waste heat or in a solar pond and reused for concentrating more sugar solutions.

[000220] In all embodiments, economics dictate apparatus configuration and process feed flow and composition.

[000221] In one embodiment, water is extracted from solutions comprising radioactive contamination. Advantageously, solutions comprising radioactive contamination generally comprise solutes having higher molecular weights; accordingly, such solutions tend to have a relatively low osmotic pressures. Radioactive contamination may take different forms. In one embodiment, the radioactive contamination comprises Cesium-137.

[000222] Cesium-137 is a dangerous radioactive material generated by the nuclear fission of uranium-235. Cesium-137 is a soft, malleable, silvery white metal and melting point of 28.4 °C and a molecular weight of 136.907. The half-life of cesium-137 is 30 years. Cesium-137 decays by emission of a beta particle, gamma rays and conversion to barium-137m. Cesium-137 is a major contributor to the total radiation released during nuclear accidents, as in case of Chernobyl and recently Fukushima-Daiichi nuclear plant of Japan. [000223] In one embodiment, water is extracted from freshwater supplies (normally used for potable water if it contains less than 500 ppm of dissolved solids) containing radioactive contamination. One cubic meter of water contaminated with Cesium-137 appears to contain just few grams of Cesium-137 that have negligible osmotic effect. In one embodiment, relatively pure water is extracted from water contaminated with Cesium-137, leaving concentrated Cesium-137. In one embodiment, the concentrated Cesium-137 is flushed from the extractor, as needed. In one embodiment, the extraction membranes are safely disposed, as needed.

[000224] In one embodiment, water is extracted (as permeate or tie-line) from a radioactive contaminated low salinity salt solution (for example 1% or 10,000 ppm salt). In one embodiment, the radioactive contamination comprises Cesium-137. In one embodiment, 2 volumes of feed comprising a 1% salinity brine comprising a given concentration of Cesium-137 is extracted to produce 1 volume of tie line and a concentrated radioactive feed product comprising 1 volume of water at 2% salinity and twice the concentration of Cesium-137. In one embodiment, 1 volume of process fluid at 4% salinity enters the lumens of the HF panels and leaves the HF lumens (plus the permeate or tie-line) as 2 volumes at of water at 2% salinity. In one embodiment, the volume of recycle (or storage) radioactive contaminated water leaving the extractor is decreased by using a process fluid that has an even higher salinity. In one embodiment, 2 volumes of radioactive contaminated water at 1% salinity is reduced to about ¼ volume of concentrated recycle radioactive contaminated water at 8% salinity by using a process fluid (in the HF lumens) having a salinity of 4%. Such practice reduces the storage requirements for radioactive contaminated water and associated maintenance In one embodiment, the process fluid has a salinity of: 3% or more; 4% or more; 5% or more; 6% or more; 7% or more; 8% or more; 9% or more; 10% or more; 11% or more; 12% or more; 13% or more; 14% or more; 15% or more; 16% or more; 17% or more; 18% or more; 19% or more; 20% or more.

[000225] Water extraction-water recovery will now be described in more detail in connection with Figures 16 and 17. Figure 16 depicts equipment arrangement of a three cell water extraction-water reverse osmosis recovery system 300. The system 300 in Fig. 16 is useful to purify water contaminated with hazardous chemicals or radioactive substance. In this embodiment, the semipermeable membranes permit water to pass through, but not foreign contamination.

[000226] In one embodiment, a first cell 300a comprising a first array 317 operates at a relatively low initial pressure. In one embodiment, the first water extraction cell 300a comprises a relatively low pressure casing 304. A downstream reverse osmosis recovery system operates at a relatively high pressure, and comprises a high pressure casing 326. In one embodiment, the downstream reverse osmosis recovery system comprises a second cell 300b and a third cell 300c comprising a second array 322 and a third array 324, respectively. As described previously, the arrays 322, 324 comprise alternating pairs of substantially perpendicular panels, each comprising a plurality of HFs.

[000227] The fluid flow in the low pressure cell 300a is similar to that described in connection with Fig. 3. In one embodiment, contaminated fluid accumulated in safe compartment 302 passes through a pump 301 at and across an initial panel 306 of the first cell 300a. As the contaminated fluid passes at relatively low pressure from and across the tail panel 306 to and across the initial panel 308 of the first cell 300a, water passes from the process fluid in the HFs into the contaminated fluid 302. The result is concentrated hazardous chemicals or radioactive substance waste 312. The concentrated hazardous chemicals or radioactive substance waste 312 is separated into radioactive waste 315 and recycle radioactive contaminated water 302. In one embodiment, the radioactive waste is safely discarded.

[000228] In one embodiment, the process also produces first concentrated process fluid 314. In one embodiment, the first concentrated process fluid 314 is separated into a first stream 316 and a second stream 316a. In one embodiment, a first stream 316 is fed to a pressure exchanger 318. In one embodiment, a second stream 316a is fed to a pump 320. In one embodiment, a pressurized first stream 316b exits the pump 320, and a pressurized second stream 318a exits the pressure exchanger 318. In one embodiment, the pressurized first stream 316b and the pressurized second stream 318a are combined to produce a feed 321.

[000229] In one embodiment, the feed 321 has a higher pressure and a reduced level of hazardous chemicals or radioactive substance contamination than contaminated fluid 302. In one embodiment, the feed 321 is charged to the downstream exchanger comprising a plurality of cells adapted to operate at higher pressures. The downstream exchanger may comprise any number of cells required to produce decontaminated process fluid 338. In Fig. 16, the downstream exchanger comprises a second cell 300b and a third cell 300c comprising a second array 322 and a third array 324, respectively.

[000230] In one embodiment, the feed 321 has a pressure sufficiently high to create a pressure differential of 50 bar (720 psi) or higher between the feed and the process fluid in the HF lumens in the second cell 300b. As the relatively high pressure feed 321 passes from and across a tail panel 328 to and across an initial panel 330 of the second array 322, water passes from the feed 321 into the process fluid in the HF lumens of the second array 322. The result is a concentrated radioactive stream 334 and a first decontaminated process fluid 332. In one embodiment, the concentrated hazardous chemicals or radioactive substance stream 334 is safely disposed. In one embodiment, the concentrated radioactive stream 334 is separated into a second hazardous chemicals or radioactive substance waste 334a, and a second waste water 334b. In one embodiment, the second hazardous chemicals or radioactive substance waste 334a is safely disposed. In one embodiment, the second waste water 334b is recycled to the first pressure exchanger 318. In one embodiment, the second waste water 334b is combined with the pressurized first stream 316b to produce the feed 321.

[000231] In one embodiment, the first decontaminated process fluid 332 is pumped in a similar fashion from cell 300b at a relatively high pressure to the third cell 300c. As the feed 321a passes across the reverse osmosis array 324 in the third cell 300c, water passes from the feed 321a into the process fluid in the HFs in the reverse osmosis array 324. The result is a second concentrated radioactive stream 336 and a decontaminated process fluid 338. In one embodiment, the concentrated radioactive stream 336 is safely disposed. In one embodiment, the concentrated radioactive stream 336 is separated into a third radioactive waste 340 and a third hazardous chemicals or radioactive substance waste water 342. In one embodiment, the third radioactive waste water 342 is recycled to the second pressure exchanger 318a. As the relatively high pressure feed 321a passes across third reverse osmosis array 324, water passes from the feed 321a into the process fluid in the HF lumens of the third reverse osmosis array 324. The result is a concentrated radioactive stream 336 and a second decontaminated process fluid 338. In one embodiment, the decontaminated process fluid 338 is used as process fluid 310. The decontaminated process fluid 338 may be used for a variety of purposes. In one embodiment, the decontaminated process fluid 338 is used as freshwater.

[000232] Figure 17 is a schematic diagram illustrating a multi-cycle process for extracting water from commercial, industrial or hazardous solutions for the purpose of recovering water and/or concentrating said solutions. The multi-cycle process of Fig. 17 is essentially similar to Fig. 16, but Fig. 16 replicates the mechanical arrangement of the apparatus and FIG. 17 outlines the basic process functions and operation.

[000233] The multi-cycle process of Fig. 17 comprises three or more integrated loops cycling continuously. In one embodiment, the three or more integrated loops operate in a harmonic mode. In one embodiment, a first loop (an "ISO" loop) extracts water and operates between a process fluid source 699 and an extraction array 702. In one embodiment, a second loop operates between the extraction array 702 and a first reverse osmosis array 704 ("RO"). In one embodiment, the second loop purifies water by retaining residual contaminants and returns this residual contaminants to the process fluid source 699, or for disposal. In one embodiment, a third loop is a redundant loop operating between the first reverse osmosis array 704 and a second reverse osmosis array 706. In one embodiment, the third loop further purifies recovered water, particularly in case of presence of hazardous substance or radioactive material. Water does not accumulate within the system. Accordingly, water is extracted in the extraction array702 at a given rate and leaves the second reverse osmosis array 706 at the given rate.

[000234] Referring to Figure 17, a process fluid 708 having a salinity of 1% or less is pumped from a process fluid source 699 in a first loop 701. In one embodiment, the process fluid 708 is processed at a rate determined by the contaminated water amount and the required treatment time. For example, if water extraction efficiency is 50%, then for every extracted unit volume of water, two units volume of raw water will be transported from process fluid source 699 and across the extraction array 702 at a rate of 2 liters/sec, or 2 m ³ /min, etc.. A relatively high salinity brine feed 734 is fed to the extraction array 702 at a relatively low pressure. In Fig. 17, the relatively high salinity brine feed 734 has a salinity of about 6% and is fed at a pressure of about 1 bar. As the relatively high salinity (6%) feed 734 passes across the extraction array 702 comprising HFs filled with relatively low salinity (1% or less) process fluid, a tie-line of water having a initial flow rate of about 1 ± liter/sec flows spontaneously from the process fluid into the relatively high salinity feed 734, producing a relatively lower salinity (3%) product 734a, having supplemented flow rate higher than the initial flow rate. In one embodiment, the supplemented flow rate is about 1 ± liter/sec.

[000235] In one embodiment, a pump Pi regulates the pressure of the process fluid 708, producing a pressurized process fluid 709. In Fig. 17, the array 702 produces concentrated process fluid 710 having an increased salinity compared to the pressurized process fluid 709. In one embodiment, the concentrated process fluid 710 has a salinity that is about twice the salinity of the pressurized process fluid 709. In one embodiment, the pressure of the concentrated process fluid 710 is regulated by a pressure regulator 712.

[000236] An intermediate salinity product 734a flows from the extraction array 702 into a second loop 701a. In one embodiment, the intermediate salinity product 734a is split into a first stream 715 and a second stream 718. In one embodiment, the first stream 715 and the second stream 718 each have a salinity of about 3% and a flow rate of about=l ± liter/sec.

[000237] In one embodiment, the first stream 715 is fed to a pressure exchanger 716 and the second stream 718 is fed to a pump 720. In one embodiment, the pump 720 uses about 6.38 K Joule of energy to increase the pressure of the second stream 718, producing an increased pressure second stream 718a. In one embodiment, the first stream 715 is fed to a pressure exchanger 716. In one embodiment, the pressure exchanger recovers pressure from the first stream 715 for subsequent use, and produces a relatively high pressure first stream 715a.

[000238] In one embodiment, the increased pressure first stream 715a and the increased pressure second stream 718a are combined to produce a second feed 722 to the first reverse osmosis array 704. As the relatively high pressure intermediate salinity second feed 722 passes across the first reverse osmosis array 704, an increased salinity second product 724 is produced. In one embodiment, the second product 724 has a salinity of about 6%.

[000239] In one embodiment, the second product 724 is split into a first stream 726 and a second stream 728. In one embodiment, the relatively high pressure of first stream 726 is fed to a pressure exchanger 716 where the pressure is recovered by pressurizing first stream 715 to produce an increased pressure first stream 715a, a reduced pressure second stream 732, and approximately 6.38 K Joule of recovered energy. In one embodiment, the relatively high pressure first stream 728 is retained by a back pressure control valve 730, and a reduced pressure first stream 731 is combined with the reduced pressure second stream 732 to form return stream 734 to the extraction array 702. In one embodiment, the return stream 734 has a salinity of about 6% and a flow rate of about 1 liter/sec.

[000240] The second feed 722, having a salinity of about 3%, passes across the first reverse osmosis array 704 having a similar structure to extraction array 702, but having dissimilar operating conditions and flow pattern. The second feed 722 has a reduced salinity compared to the process fluid 709. In one embodiment, the reduced salinity is about 3%. The second feed 722 also has a higher flow rate than the process fluid 709. In one embodiment the flow rate is about 2 liter/sec.

[000241] In one embodiment, the second feed 722 is exchanged with feed 758 across membranes of the first reverse osmosis array 704, to produce a reduced salinity second product 740, which serves as a feed to a third loop 701b. In one embodiment, the function of this third loop 701b is identical to the function of the second loop.

[000242] In one embodiment, the reduced salinity second product 740 is split into a first stream 742 and a second stream 744. In one embodiment, the first stream 742 and the second stream 744 each have a salinity of about 3% and a flow rate of about 1 ± liter/sec.

[000243] In one embodiment, the first stream 742 is fed to a pressure exchanger 716a and the second stream 744 to a pump 720a. In one embodiment, the pump 720a uses about 6.38 K Joule of energy to increase the pressure of the second stream 744, producing an increased pressure second stream 744a. In one embodiment, the first stream 742 is fed to a pressure exchanger 716a. In one embodiment, pressure exchanger 716a produces a relatively high pressure first stream 742a. [000244] In one embodiment, the increased pressure first stream 744a and the increased pressure second stream 742a are combined to produce a second feed 746 to a second reverse osmosis array 706. As the increased pressure, reduced salinity second feed 746 passes across the third array 706, an increased salinity third product 748 is produced. In one embodiment, the third product 748 has a salinity of about 6%.

[000245] In one embodiment, the third product 748 is split into a first stream 750 and a second stream 752. In one embodiment, the first stream 750 is fed to the pressure exchanger 716a where the pressure is recovered by pressurizing feed 742 to the third reverse osmosis array 706, producing a reduced pressure stream 754 and generating approximately 6.38 K Joule of energy. In one embodiment, the first stream 752 is retained by a back pressure control valve 753, producing a reduced pressure first stream 756. In one embodiment, the reduced pressure first stream 756 and the reduced pressure second stream 754 are combined to produce an increased salinity; low pressure feed 758 to the first reverse osmosis array 704. In one embodiment, the feed 758 has a salinity of about 6% and a flow rate of about 1 liter/sec. The apparatus may be modified to include a different number of arrays. In one embodiment, the third array 706 produces product fluid 760.

Physics and Thermodynamics

[000246] The use of the membrane element and hollow fiber panel described herein is rooted in the field of physics and pertains to the development of a chemical engineering conceptual process design, presenting a new vision in the energy field. The following discussion of basic physics and thermodynamics will assist in understanding the method and apparatus.

[000247] The first law of thermodynamics rules out the possibility of constructing a machine that can spontaneously create energy. However, the first law of thermodynamics does not rule out the possibility of transferring energy from one form into another.

[000248] Internal energy (U) generalized differential form can be presented as:

dU= TdS - pdV + μ dN + <p dQ + \ dp + ψάτη + fdA + (Eq. 1) where, entropy S, volume V, amount of substance N, electric power Q, momentum p, mass m, area A, etc. are extensive properties and temperature T, pressure p, chemical potential μ, electrical potential φ, velocity v, gravitational potential ψ, surface tension £, etc. are energy-conjugated intensive quantities.

[000249] This generalized relation is reduced to account for osmotic effect as:

dU= TdS - pdV + ¾ μ _ί dN _t (Eq. 2) μι is the chemical potential of the -th chemical component, joules per mol.

Ni (or n is the number of particles (or moles) of the /-th chemical component.

[000250] In thermodynamics, the Gibbs free energy is a thermodynamic potential that measures the "useful" or process-initiating work obtainable from an isothermal, isobaric thermodynamic system. The Gibbs free energy is the maximum amount of non-expansion work that can be extracted from a closed system. This maximum can be attained only in a completely reversible process.

[000251] Gibbs free energy, G (τ, p, N) attained in a reversible process can be presented in simplified form as: G = U + pV -TS. Expanding this relation in a differential form, with substitution of Eq. 2

dG = dU +d(pV) - d(TS) = TdS -pdV + ¾ μ, dN, +d(pV) - d(TS)

= TdS - pdV + ¾ μι dNi + pdV + Vdp - SdT- TdS (Eq. 3)

Eliminating opposite sign terms, osmotic effect in terms of Gibbs free energy is: dG = Vdp - SdT + ¾ _i dN _t (Eq. 4)

Gibbs free energy when pressure and temperature are constant (dp = 0 and dT = 0), a condition for process reversibility, results in:

dG =∑ _t μ, dNi (Eq. 5)

[000252] To define the relation between pressure and chemical potential, the chemical potential in Eq. 6 is assumed to be negligible, then dG = Vdp, but since pV= nRT, from perfect gas equation of state, by substitution, dG = nRT dp/p. By integration between p ₀ and p gives:

AG = G _p - Gpo = nRT I dp/p = nRTln (p/p ₀ ).

For one mole (n=l) and in term of chemical potential given earlier by Eq. 5

μ = μ ⁰ + RT Ln (p/p ₀ ) (Eq. 6)

Derivation of this relation in terms of activity coefficient, considering real solution results in;

μ _Α = μ _Α ^* + RT n a _A (Eq. 7)

Then, osmotic pressure mathematical general form can be presented as: Δπ = Δρ = RTACs (Eq. 8)

[000253] The osmotic pressure π was originally proposed by Nobel Laureate Van't Hoff and modified to include Staverman's osmotic reflection coefficient to become;

π = <E>icRT (Eq. 9) Where:

π = osmotic pressure or force imposed on the membrane given in bars, atm, psi, etc.

Φ = Osmotic Reflection Coefficient (NaCl = 0.93, CaCl ² = 0.86, Mg CaCl ² = 0.89, etc.),

i = Ions concentration per dissociated solute molecule (Na ⁺ and CI ^" ions = 2), c = molar concentration of the salt ions,

R = gas constant (0.08314472 liter bar / (k.mol)),

T = ambient temperature in absolute Kelvin degrees (20°C +273° = 293°K).

[000254] The average salinity of seawater is about 3.5% (35 gram/liter), comprising ocean salts as solute, mostly in the form of sodium chloride (NaCl). For simplicity of calculation, it is assumed that seawater contains 35 grams NaCl/liter. The atomic weight of sodium is 23 grams. The atomic weight of chlorine is 35.5 grams, so the molecular weight of NaCl is 58.5 grams. The number of NaCl moles in seawater is 35 / 58.5 = 0.598 mol/liter and the osmotic pressure of seawater is π = [0.93] [2] [0.598 mol/liter] [0.08314 liter .bar/ (k.mol)] [293 K] = 27.11 bar

Since one bar = 100,000 Pascal (Pa) and one kilogram (force) per square centimeter (kgf / m ² ) = 98066.5 Pascal, computation of osmotic pressure, π and energy of seawater (SW _£ ) and lake brine (LBg) can be presented in several forms: π = [27.11 x 10 ⁵ Pa] / [98066.5 Pa / (kg _f / cm ² )] = 27.64 kgf cm ² π = [Π.6Α kg _f cm ² ] [m/100 cm] [1000 cm ³ /liter] = 276.4 kg _f . ml liter a. SW _£ = [276.4 kg _f . m/liter] [9.80665 Joule/ kg _f . m] = 2711 Joule/liter = 2.711 MJ/m ³ b. SW _£ = [2711 Joule/liter] [1 cal/ 4.184 J] [1 kcal/1000 cal] = 0.6479 kcal/liter c. SW _£ = [2711 Joule/liter] [1000 liter/m ³ ] = 2.710 MJ/m ³ = 0.751 kWh/m ³

[000255] For generating power substantially continuously, which typically is the case with power generation systems, the theoretical potential power capacity of this system is:

d. [2.711 MJ/m ³ ] [lm ³ /s] [3600 s] = 9.759 x 10 ⁹ J = [9.759 x 10 ⁹ W.s] [h /3600 s] = 2,711 kWh e. SW _£ = [2,711 kWh] [24 hrs/day] [365 days/year] = 23.75 x 10 ⁶ kWh annually.

[000256] I ^{n me case} °f ^a hyper saline lake such as the Qattara Depression- Egypt, Chott El Jerid- Tunisia, Lake Torrens- Australia, or any typical natural or manmade domain, the amount of average salt concentration can reach saturation (359 gram/liter at 25 centigrade) mostly in the form of sodium chloride (NaCl). Considering lake salinity is 33% (330 gram/liter), then the lake brine osmotic pressure can be estimated as: π = [0.93] [2] [5.641 mol/liter] [0.08314 liter, bar/ (k.mol)]. [293 K] = 255.593 bar [000257] For substantially continuous power generation, the theoretical potential power capacity of the lake brine (LB) of such system where; 1 W= J/s, 1 W.s = J, 1 kWh = 3.6 x 10 ⁶ J, is:

LB _E = [25.559 MJ/m ³ ] [lmVs] [3600 s] = [92.0124 x 10 ⁹ J] [1 kWh/3.6 xlO ⁶ J] = 25,559 kWh LB _£ = [25,559 kWh] [24 hrs/day] [365 days/year] = 223.897 x 10 ⁶ kWh / year, per 1 m ³ per sec.

[000258] Regarding Induced Symbiotic Osmosis [ISO] membrane flux, the simplest equation to describe the relationship between osmotic, hydraulic pressures and water flux, J _w is based on calculating the log mean concentration difference ("LMCD"). LMCD is a system driving force and it assists in realistic determination of equipment size and power generation. LMCD has been calculated for all design cases since it is a system efficiency parameter, particularly when energy regeneration efficiency is debatable.

J _w = A Kp [Φ Δπ @ A _m - ΔΡ] (Eq. 10)

Where J _w is water flux, Kp is the hydraulic permeability of the membrane, A is membrane area, Απ is the difference in osmotic pressures on the two sides of the membrane, Δ is the difference in hydrostatic pressure where negative values of J _w indicating reverse osmotic flow. Φ, reflective coefficient, AQ _m is log mean concentration difference (LMCD).

[000259] The calculated logarithmic mean concentration difference should be the same as or less than the membrane's limited operating pressure. The number of cells required in a particular power train can be determined based on: (a) the initial salinity of the feed and/or process fluid, (b) the operating pressures, and/or (c) a combination thereof. The logarithmic mean concentration difference may be reduced by increasing the number of cells. The logarithmic mean concentration difference may be increased by reducing the number of cells.

[000260] Concentration polarization results of accumulation of dissolved salt at the membrane surface, creating a relatively high localized osmotic gradient. This relatively high localized osmotic gradient reduces normal osmotically driven permeate diffusion and hinders membrane flux, in addition of blocking the flow pass. In general, membranes operating in induced osmosis mode are less susceptible to this phenomenon due to the low pressure imposed on membrane as compared with membranes in reverse osmosis service. In one embodiment, the feed is pretreated to remove suspended solids.

[000261] In one embodiment, membrane fouling and concentration polarization phenomenon are reduced by one or more of the following:

i. Maintaining turbulence flow across and along membrane surfaces preferably at a Reynolds' Number of 3,000 or more, 3,100 or more, 3,200 or more, 3,300 or more, 3,400 or more, 3,500 or more, preferably above 3,500. In one embodiment, excessive use of pumping energy is avoided if the Reynolds' Number is maintained at 6,000 or less. In one embodiment, the Reynolds Number is maintained at less than 6,000. Reynolds number is defined by the ratio of dynamic pressure (p u ² ) and shearing stress (μ u / L) and expressed in mathematical function as:

Re = (p u ² ) / (μ -u /L) = p u L /μ (Eq. 11) Where;

= Reynolds Number (non-dimensional) density (kg/m ³ , lb _m /ft ³ )

c. u = velocity cross section area of the duct or

d. μ = dynamic viscosity (Ns/m ² , Ib _r Js ft) e. L = characteristic length (m,ft) also known as the hydraulic diameter, d _h for ducts, passageways, annuli, etc.

Where d _h = (4) (cross sectional area of duct)/ wetted perimeter

f. v = kinematic viscosity (m ² /s, ff/s)

Side-mounting electromechanical vibrators on membrane array encasements. The electromechanical vibrators may operate at any effective frequency. In one embodiment, the electromechanical vibrators operate intermittently or continuously at a vibration of about 30 Hertz or more, 35 Hertz or more, 40 Hertz or more, 45 Hertz or more, 50 Hertz or more, 55 Hertz or more, 60 Hertz or more, 65 Hertz or more, or 70 Hertz. The electromechanical vibrators may travel any effective distance. In one embodiment, the electromechanical vibrators travel a distance of 3 mm or more, 3.5 mm or more, 4 mm or more, 4.5 mm or more, 5 mm or more, 5.5 mm or more, or 6 mm; iii. Minimizing contact points and associated laminar or stagnant flow between fibers, which can produce salt build up between contacting fibers, by relatively loosely mounting the semipermeable membranes. In one embodiment hollow fibers are relatively loosely packed and retained within a frame;

iv. Regularly flushing the membranes with desalinated fluid or water upon dropping of power generation or desalination quality. Flushing may occur at substantially any designated power drop. In one embodiment, flushing occurs at power drops of 1% or more , 2% or more, 3% or more 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, or 10%;

v. Using a hydrophilic semipermeable membrane such as cellulose acetate which tends to avoid formation of foreign matter on the membrane surface and tends to mitigate concentration polarization. vi. Using surfactants in enclosed middle cells;

vii. Continuously on-line monitoring salinity changes within each loop. In one embodiment, salinity is automatically adjusted by injecting or withdrawing saline solution. In one embodiment, salinity is adjusted by adding water having a desired salinity.

viii. Saving power and making impeding fouling build up on the semipermeable membrane, in one embodiment, by using dual diaphragm pumping systems.

[000262] Persons of ordinary skill in the art will recognize that many modifications may be made to the foregoing description. The embodiments described herein are meant to be illustrative only and should not be taken as limiting the invention, which will be defined in the claims.