Increased flow rate in electrodeionization devices

Abstract

The electrodeionization device includes a spacer having a first inlet port, a first outlet port, a first plurality of first flow paths configured to direct fluid in a first direction from the first inlet port to the first outlet port, and a second flow path in serial fluid communication with the first plurality of first flow paths between the first inlet port and the first outlet port and configured to direct fluid in a second direction from the first inlet port to the first outlet port, the second direction being different than the first direction.

Description

[Technical field]

[0001] Aspects and embodiments disclosed herein relate generally to electrochemical membrane systems and methods for making the same. [Background technology]

[0002] Devices that use electric fields to purify fluids can be used to treat water and other liquids that contain dissolved ionic species. Two types of devices that treat water in this way are electrodeionization devices and electrodialysis devices. Within these devices, there are concentrate and dilute compartments separated by ion-selective membranes. Electrodialysis devices typically contain alternating electroactive semipermeable anion and cation exchange membranes. The space between the membranes is configured to form a liquid flow compartment with an inlet and an outlet. An electric field applied via the electrodes draws the dissolved ions to their respective counter electrodes and through the anion and cation exchange membranes. This generally removes ions from the liquid in the dilute compartment and leaves the liquid in the concentrate compartment enriched with the transferred ions. Summary of the Invention

[0003] According to one embodiment, there is provided an electrochemical device including a spacer comprising a first inlet port, a first outlet port, a first plurality of flow channels configured to direct fluid in a first planar direction parallel to a major plane of the spacer in a portion of a flow path from the first inlet port to the first outlet port, and a manifold in serial fluid communication with the first plurality of flow channels between the first inlet port and the first outlet port and configured to direct fluid in a second planar direction parallel to the major plane of the spacer and different from the first planar direction in another portion of the flow path from the first inlet port to the first outlet port.

[0004] In some embodiments, the spacer further comprises an inlet manifold in serial fluid communication between the first inlet port and the first plurality of flow channels and configured to direct fluid in a third planar direction parallel to a major plane of the spacer and different from the first and second planar directions, and an outlet manifold in serial fluid communication between the first outlet port and the first plurality of flow channels and configured to direct fluid in the third planar direction.

[0005] In some embodiments, the manifold is disposed along a diameter of the spacer.

[0006] In some embodiments, the first plurality of flow paths is disposed between the manifold and the first inlet.

[0007] In some embodiments, the spacer further comprises a second inlet.

[0008] In some embodiments, the second inlet is substantially opposite the first inlet of the spacer.

[0009] In some embodiments, the second plurality of flow paths is disposed between the manifold and the second inlet.

[0010] In some embodiments, the direction of fluid flow through the first plurality of flow channels is substantially opposite to the direction of fluid flow through the second plurality of flow channels.

[0011] In some embodiments, the direction of fluid flow through the manifold is substantially perpendicular to the direction of fluid flow through the first plurality of flow channels and the direction of fluid flow through the second plurality of flow channels.

[0012] In some embodiments, the manifold includes a wall disposed at an acute angle relative to the average direction of fluid flow through the manifold.

[0013] In some embodiments, the manifold includes two walls each oriented at an acute angle relative to the average direction of fluid flow through the manifold.

[0014] In some embodiments, the cross-sectional area of ​​the manifold increases from the end furthest from the first outlet port to the end closest to the first outlet port.

[0015] In some embodiments, the width of the manifold increases from the end furthest from the first outlet port to the end closest to the first outlet port.

[0016] In some embodiments, the first plurality of flow paths is disposed between the manifold and the first outlet.

[0017] In some embodiments, the spacer further comprises a second outlet.

[0018] In some embodiments, the second outlet is substantially opposite the first outlet of the spacer.

[0019] In some embodiments, the second plurality of flow paths is disposed between the manifold and the second outlet.

[0020] In some embodiments, the direction of fluid flow through the first plurality of flow channels is substantially opposite to the direction of fluid flow through the second plurality of flow channels.

[0021] In some embodiments, the direction of fluid flow through the manifold is substantially perpendicular to the direction of fluid flow through the first plurality of flow channels and the direction of fluid flow through the second plurality of flow channels.

[0022] In some embodiments, the cross-sectional area of ​​the manifold increases from the end furthest from the first outlet port to the end closest to the first outlet port.

[0023] In some embodiments, the width of the manifold increases from the end furthest from the first outlet port to the end closest to the first outlet port.

[0024] In some embodiments, the electrochemical device comprises an electrodeionization device, and the first plurality of first flow channels each contain beads of anion and cation exchange resin having a bimodal size distribution.

[0025] In some embodiments, the anion and cation exchange resin beads proximate the walls of the first plurality of first flow channels have a smaller average size than the anion and cation exchange resin beads proximate the center of the first plurality of first flow channels and further from the walls of the first plurality of first flow channels.

[0026] In some embodiments, the manifold includes openings that are smaller in size than the size of the beads of the ion exchange resin.

[0027] According to another aspect, an electrochemical device is provided that includes a spacer, the spacer comprising a first inlet port, a first outlet port, and a first plurality of flow channels configured to direct fluid in a first direction in a portion of a fluid path from the first inlet port to the first outlet port, the plurality of flow channels configured such that a velocity of the fluid through the first plurality of flow channels varies as a function of distance from the first inlet port.

[0028] In some embodiments, the spacer further comprises a manifold in serial fluid communication with the first plurality of flow paths between the first inlet port and the first outlet port and configured to direct the fluid in a second direction, different from the first direction, in another portion of the flow path from the first inlet port to the first outlet port.

[0029] In some embodiments, the spacer further comprises a second inlet.

[0030] In some embodiments, the spacer further comprises a second plurality of flow channels disposed between the manifold and the second inlet.

[0031] In some embodiments, the cross-sectional area of ​​the first plurality of flow channels varies with distance from the first inlet port.

[0032] In some embodiments, the height of the first plurality of channels varies with distance from the first inlet port.

[0033] In some embodiments, the width of the first plurality of flow channels varies with distance from the first input port.

[0034] In some embodiments, a width of the first plurality of first flow channels varies with distance from the first input port.

[0035] In some embodiments, the walls of the first plurality of channels are non-parallel.

[0036] In some embodiments, a cross-sectional area of ​​the first plurality of flow channels remains substantially the same as a function of distance from the first inlet port, and at least one of a width or height of the first plurality of flow channels varies as a function of distance from the first inlet port.

[0037] In some embodiments, the spacer is a diluent spacer and the first plurality of first flow channels are diluent compartments.

[0038] In some embodiments, the electrochemical device further comprises a concentrate spacer having an upper surface disposed relative to the lower surface of the dilute spacer, the concentrate spacer including a third plurality of flow paths having dimensions complementary to the dimensions of the first plurality of flow paths.

[0039] In some embodiments, the electrochemical device comprises an electrodeionization device, wherein one or more of the first plurality of flow paths, the second plurality of flow paths, or the third plurality of flow paths each comprise beads of anion and cation exchange resin having a bimodal size distribution, and the dilute spacer and the concentrate spacer form a cell pair that exhibits a conductivity at least 20% higher than the conductivity of a cell pair comprising a dilute spacer and a concentrate spacer that comprise only anion exchange resin beads having uniform sizes and cation exchange resin beads having uniform sizes.

[0040] In some embodiments, the height of the second plurality of flow channels varies with distance from the second inlet port at the same rate that the height of the first plurality of flow channels varies with distance from the first inlet port.

[0041] In some embodiments, the electrochemical device comprises an electrodeionization device, and the first plurality of first flow channels each contain beads of anion and cation exchange resin having a bimodal size distribution.

[0042] According to another aspect, an electrochemical device is provided that includes a spacer, the spacer comprising an inlet port, an outlet port, a first plurality of flow paths configured to direct fluid from the inlet port to the outlet port, a second plurality of flow paths configured to direct fluid from the inlet port to the outlet port, and a mixing zone fluidly disposed between the first and second plurality of flow paths, the mixing zone configured to receive fluid from each of the first plurality of flow paths and direct fluid to each of the second plurality of flow paths.

[0043] In some embodiments, the mixing zone includes a wall disposed between the first and second plurality of flow paths, the wall having a plurality of openings configured to facilitate mixing of the fluids within the mixing chamber.

[0044] In some embodiments, the wall defines a downstream end of the first plurality of flow chambers.

[0045] In some embodiments, the first plurality of channels comprises beads of ion exchange resin and the plurality of openings have a dimension smaller than the beads of ion exchange resin.

[0046] In some embodiments, the mixing chamber includes an internal structure configured to promote mixing of fluids introduced into the mixing chamber from the first plurality of channels.

[0047] In some embodiments, the mixing chamber further includes a second wall disposed between the first plurality of flow paths and the second plurality of flow paths, the second wall having a second plurality of openings.

[0048] In some embodiments, the second wall defines an upstream end of the second plurality of fluid paths.

[0049] In some embodiments, the second plurality of channels comprises beads of ion exchange resin and the second plurality of apertures has a dimension smaller than the beads of ion exchange resin.

[0050] In some embodiments, the first plurality of flow paths and the second plurality of flow paths are equal in number.

[0051] In some embodiments, each of the first plurality of flow paths is aligned with a corresponding one of the second plurality of flow paths.

[0052] In some embodiments, the first plurality of channels and the second plurality of channels have substantially the same dimensions.

[0053] In some embodiments, the direction of fluid flow through the first plurality of flow channels is substantially parallel to the direction of fluid flow through the second plurality of flow channels.

[0054] In some embodiments, the rate of fluid flow through the first plurality of flow paths is substantially the same as the rate of fluid flow through the second plurality of flow paths.

[0055] In some embodiments, the mixing zone has a width in the average direction of fluid flow through the mixing zone that is narrower than a width of the first plurality of flow channels in a direction perpendicular to the average direction of fluid flow through the first plurality of flow channels.

[0056] In some embodiments, the width of the mixing zone is substantially constant over the length of the mixing zone.

[0057] In some embodiments, the mixing zone has a length in a direction perpendicular to the average flow direction of fluid through the mixing zone that is greater than a length of the first plurality of flow channels in the average flow direction of fluid through the first plurality of flow channels.

[0058] In some embodiments, the length of the mixing zone is substantially constant across the width of the mixing zone.

[0059] In some embodiments, the electrochemical device comprises an electrodeionization device, wherein a first plurality of flow paths comprises beads of anion and cation exchange resin having a different average size than beads of anion and cation exchange resin contained in a second plurality of flow paths.

[0060] In some embodiments, the first plurality of flow paths each contain beads of anion and cation exchange resin having a monomodal size distribution.

[0061] In some embodiments, the second plurality of flow paths comprises beads of anion and cation exchange resins each having a bimodal size distribution.

[0062] According to another aspect, an electrodeionization device is provided that includes a spacer. The spacer includes an inlet port, an outlet port, a first plurality of flow paths configured to direct fluid from the inlet port to the outlet port, and a second plurality of flow paths configured to direct fluid from the inlet port to the outlet port. The second plurality of flow paths is arranged in series with the first plurality of flow paths or configured to direct fluid in a direction opposite to the direction of fluid flow through the first plurality of flow paths. Ion exchange media beads are disposed within each of the first and second plurality of flow paths. A size distribution of the ion exchange media beads varies from the inlet to the outlet of the first plurality of flow paths, from the inlet to the outlet of the second plurality of flow paths, or from the first plurality of flow paths to the second plurality of flow paths.

[0063] In some embodiments, the ion exchange media beads include cation exchange media beads and anion exchange media beads.

[0064] In some embodiments, the cation exchange media beads have a different size distribution than the anion exchange media beads.

[0065] In some embodiments, the first plurality of flow paths or the second plurality of flow paths include different number ratios of cation exchange media beads to anion exchange media beads.

[0066] In some embodiments, one of the first plurality of flow paths or the second plurality of flow paths has substantially the same total surface area of ​​the cation exchange media beads and the anion exchange media beads.

[0067] In some embodiments, one of the first plurality of flow paths or the second plurality of flow paths comprises cation exchange media beads having a first packing density and anion exchange media beads having a second packing density different from the first packing density.

[0068] In some embodiments, one of the first plurality of flow paths or the second plurality of flow paths includes cation exchange media beads having a first monomodal size distribution with a first median size and anion exchange media beads having a second monomodal size distribution with a second median size different from the first median size.

[0069] In some embodiments, one of the cation exchange media beads or the anion exchange media beads has a bimodal size distribution.

[0070] In some embodiments, the cation exchange media beads and anion exchange media beads collectively increase in volume during use of the electrodeionization device compared to when they were initially packed into the first and second plurality of flow channels, reducing the void volume within the first and second plurality of flow channels by at least 5%.

[0071] In some embodiments, the cation exchange medium beads include larger beads having substantially the same size and smaller beads having substantially the same size.

[0072] In some embodiments, the first and second pluralities of flow paths are arranged in series, and the average size of the ion exchange media beads decreases with distance along the flow path through the first and second pluralities of flow paths.

[0073] In some embodiments, the second plurality of flow paths is disposed downstream from the first plurality of flow paths, and the average size of the ion exchange media beads is smaller in the second plurality of flow paths than in the first plurality of flow paths.

[0074] In some embodiments, the average size of the ion exchange media beads decreases with distance along a flow path through one of the first plurality of flow paths or the second plurality of flow paths.

[0075] In some embodiments, the packing density of the ion exchange media beads varies either from the inlet to the outlet of the first plurality of flow paths, from the inlet to the outlet of the second plurality of flow paths, or from the first plurality of flow paths to the second plurality of flow paths.

[0076] In some embodiments, the packing density of the ion exchange media beads is greater near the walls than near a central region of one of the first plurality of channels or the second plurality of channels.

[0077] In some embodiments, one of the first plurality of flow paths or the second plurality of flow paths comprises a layered bed of ion exchange resin including a layer of cation exchange resin, a layer of anion exchange resin, and a layer of mixed anion and cation exchange resin.

[0078] In some embodiments, the electrochemical or electrodeionization device further comprises a non-uniform ion exchange membrane disposed on either or both the top or bottom of the spacer.

[0079] Further aspects, embodiments, and advantages of these exemplary aspects and embodiments are described in detail below. The embodiments disclosed herein may be combined with other embodiments in any manner consistent with at least one of the principles disclosed herein, and references to "embodiments," "some embodiments," "alternative embodiments," "various embodiments," "an embodiment," and the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described may be included in at least one embodiment. Terms used herein do not necessarily all refer to the same embodiment.

[0080] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a similar numeral. For clarity, every component may not be labeled in every figure. In the drawings: [Brief description of the drawings]

[0081] [Figure 1A] FIG. 1 shows an example of an assembled electrodeionization (EDI) device. [Figure 1B] FIG. 2 illustrates a partial exploded view of an example EDI device. [Figure 1C] FIG. 2 is a diagram showing an example of a cell pair of an EDI device. [Figure 1D] 1D illustrates fluid flow through an example cell pair of the EDI device of FIG. 1C. [Diagram 2] FIG. 1 shows examples of dilute and concentrate spacers for an EDI device. [Diagram 3] FIG. 1 shows an example of a high flow EDI spacer set. [Figure 4A] FIG. 1 illustrates an example of fluid flow through an EDI spacer. [Figure 4B] FIG. 13 illustrates another example of fluid flow through an EDI spacer. [Diagram 5]FIG. 13 shows another example of a high flow EDI spacer. [Figure 6] FIG. 1 illustrates an example of a high flow EDI dilution spacer. [Figure 7] 7A-7C show examples of high flow EDI concentrate spacers that can be mated with the diluent spacer of FIG. 6. [Figure 8] FIG. 13 shows an example of an EDI spacer including channels of varying width. [Figure 9] FIG. 13 shows an example of an EDI spacer including a mixed zone. [Figure 10] FIG. 13 illustrates how the packing density of anion and cation exchange beads can be varied within the channels of an EDI spacer. [Figure 11] FIG. 13 illustrates how the size distribution of anion- and cation-exchange beads in the flow channels of an EDI spacer can differ. [Figure 12] FIG. 13 illustrates how anion or cation exchange beads in the flow channels of an EDI spacer can have different populations with different size distributions. [Figure 13A] FIG. 13 illustrates how the size of ion exchange media beads can change along a flow path through a channel of an EDI spacer. [Figure 13B] FIG. 13 illustrates another way of showing how the size of ion exchange media beads can change along a flow path through a channel of an EDI spacer. [Figure 14A] FIG. 13 illustrates how the packing density of ion exchange media beads can vary along a flow path through a channel of an EDI spacer. [Figure 14B] FIG. 13 illustrates another way of showing how the packing density of ion exchange media beads can vary along a flow path through a flow channel of an EDI spacer. [Figure 15] FIG. 13 illustrates how the size and packing density of ion exchange media in the channels of an EDI spacer can vary with distance from the walls of the channels. [Figure 16] FIG. 13 illustrates how different types of ion exchange media bead beds can be overlapped in the flow channels of an EDI spacer. [Figure 17A] FIG. 1 shows a portion of an example of a irregular ion exchange membrane including partial spherical protrusions that may be utilized in embodiments disclosed herein. [Figure 17B] FIG. 17B shows beads of ion exchange resin disposed on the surface of the irregular ion exchange membrane of FIG. 17A. [Figure 17C] FIG. 17B is a diagram showing the dimensions of the protrusions of the irregular ion exchange membrane of FIG. 17A. [Figure 17D] FIG. 17B is a diagram showing the spacing of protrusions of the irregular ion exchange membrane of FIG. 17A. [Figure 17E] FIG. 2 shows a portion of an example of a irregular ion exchange membrane including pillar-like protrusions that may be utilized in embodiments disclosed herein. [Figure 17F] FIG. 17F is an isometric view showing beads of ion exchange resin disposed on the surface of the irregular ion exchange membrane of FIG. 17E. [Figure 17G] FIG. 17F is a cross-sectional view showing beads of ion exchange resin disposed on the surface of the irregular ion exchange membrane of FIG. 17E. [Figure 17H] FIG. 17F is an isometric view showing two layers of ion exchange resin beads disposed on the surface of the irregular ion exchange membrane of FIG. 17E. [Figure 17I] FIG. 17F is a diagram showing the dimensions of the protrusions of the irregular ion exchange membrane of FIG. 17E. [Figure 17J] FIG. 17F is a diagram showing the spacing of protrusions of the irregular ion exchange membrane of FIG. 17E. [Figure 17K] FIG. 1 shows a portion of an example of a irregular ion exchange membrane containing recesses that may be utilized in embodiments disclosed herein. [Figure 17L] FIG. 17K shows an isometric view of beads of ion exchange resin disposed on the surface of the irregular ion exchange membrane of FIG. [Figure 17M] FIG. 17K is a cross-sectional view showing beads of ion exchange resin disposed on the surface of the irregular ion exchange membrane of FIG. [Figure 17N] FIG. 17K shows dimensions of recesses in the irregular ion exchange membrane. [Figure 17O] FIG. 17K is a diagram showing the spacing of recesses in the irregular ion exchange membrane of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] The aspects and embodiments disclosed herein are not limited to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The aspects and embodiments disclosed herein are capable of other embodiments and of being practiced or carried out in various ways.

[0083] Electrodeionization (EDI) is a process that removes, or at least reduces, one or more ionized or ionizable species from water by using an electroactive medium and an electric potential to affect ion transport. The electroactive medium usually serves to alternately collect and release ionizable and / or ionizable species, and in some cases may continuously facilitate the transport of ions by ionic or electronic replacement mechanisms. EDI devices may include electrochemically active media of permanent or temporary charge and may operate in batch, intermittent, continuous, and / or polarity reversal modes. EDI devices may operate to facilitate one or more electrochemical reactions specifically designed to achieve or enhance performance. Additionally, such electrochemical devices may comprise an electrically active membrane, such as a semipermeable or selectively permeable ion exchange membrane or a bipolar membrane. Continuous electrodeionization (CEDI) devices are EDI devices known to those skilled in the art that operate such that water purification proceeds continuously while the ion exchange material is continuously recharged. CEDI techniques may include processes such as continuous deionization, packed cell electrodialysis, or electrodialysis. Under controlled conditions of voltage and salinity, in a CEDI system, water molecules can be decomposed to produce hydrogen or hydronium ions or species and hydroxide or hydroxyl ions or species that can regenerate the ion exchange media in the device and facilitate the release of captured species therefrom. In this manner, the water stream being treated can be continuously purified without the need for chemical recharging of the ion exchange resin.

[0084] Electrodialysis (ED) devices operate on a similar principle to CEDI, but ED devices typically do not contain an electroactive medium between the membranes. The lack of an electroactive medium results in high electrical resistance, which can hinder ED operation in feedwaters with low salinity. Also, operating an ED in feedwaters with high salinity can increase current consumption, so to date, ED equipment has been most effectively used in feedwaters with moderate salinity. In ED-based systems, the lack of an electroactive medium makes water splitting inefficient, and operation in such conditions is generally avoided.

[0085] In CEDI and ED devices, multiple adjacent cells or compartments are typically separated by a permselective membrane through which either positively or negatively charged species may pass, but typically not both. In such devices, a concentrating compartment is typically located between the diluting or depleting compartment and the concentrating compartment. In some embodiments, a cell pair may refer to a pair of adjacent concentrating and diluting compartments. As water passes through the depleting compartment, ions and other charged species are typically drawn from the depleting compartment to the adjacent concentrating compartment under the influence of an electric field, typically a DC field. Positively charged species are typically drawn to a cathode, typically located at one end of the stack of multiple depleting and concentrating compartments, and negatively charged species are similarly drawn to an anode, typically located at the opposite end of the stack of compartments. The electrodes are typically housed in electrolyte compartments that are partially isolated from fluid communication with the depleting and / or concentrating compartments. Once in the concentrating compartment, the charged species are typically captured by a barrier of a permselective membrane that at least partially defines the concentrating compartment. For example, anions are typically prevented from migrating further from the concentrating compartment towards the cathode by a cation selective membrane. Once trapped in the concentrating compartment, the trapped charged species can be removed in the concentrate stream.

[0086] In CEDI and ED devices, a DC electric field is typically applied to the cell from a voltage and current source that is applied to the electrodes (anode or positive electrode, and cathode or negative electrode). The voltage and current source (collectively the "power source") itself may be powered by a variety of means, such as an AC source, or a source derived from, for example, solar, wind, or wave power. At the electrode / liquid interface, electrochemical half-cell reactions occur that initiate and / or facilitate the movement of ions through the membrane and compartment. The specific electrochemical reactions that occur at the electrode / interface may be controlled to some extent by the concentration of salts in the specialized compartments that house the electrode assemblies. For example, feeding a sodium chloride-rich solution to the anode electrolyte compartment tends to produce chlorine gas and hydrogen ions, whereas feeding it to the cathode electrolyte compartment tends to produce hydrogen gas and hydroxide ions. Generally, hydrogen ions produced in the anode compartment combine with free anions, such as chloride ions, to maintain charge neutrality and produce a hydrochloric acid solution. Similarly, hydroxide ions produced in the cathode compartment combine with free cations, such as sodium ions, to maintain charge neutrality and produce a sodium hydroxide solution. The reaction products in the electrode compartments, such as the chlorine gas and sodium hydroxide produced, may be utilized in the process for disinfection purposes, membrane cleaning and fouling purposes, pH adjustment purposes, if desired.

[0087] Plate-and-frame and spiral wound designs are used in various types of electrochemical deionization devices, including but not limited to electrodialysis (ED) and electrodeionization (EDI) devices. Commercially available ED devices are typically of plate-and-frame design, while EDI devices are available in both plate-and-frame and spiral configurations.

[0088] Electrodeionization (EDI) devices are typically assembled from a stack of cell pairs separated at both ends by electrodes, end blocks, and end plates. Each cell pair consists of a cation exchange membrane, a spacer defining a dilute compartment, an anion exchange membrane, and a spacer defining a concentrate compartment. The entire assembly of stacked components is mechanically compressed and secured in place by tie rods.

[0089] The dilute and concentrate compartments are filled with an ion exchange medium to facilitate ion transfer and reduce electrical resistance. In most commercially available EDI devices, the medium comprises an ion exchange resin. The inter-membrane distance between each compartment can range from 0.09 to 0.40 in. (0.23 to 1.0 cm).

[0090] An example of an EDI device is shown in a perspective view in FIG. 1A and in a partially exploded view in FIG. 1B. As shown, the EDI device 100 includes a plurality of stacked spacers and ion-selective permeable membranes, shown collectively at 105 in FIG. 1A, held between a pair of end plates 110. The end plates 110 are connected to each other by a plurality of tie rods 115, which exert pressure on the stack of spacers and membranes to prevent leakage from the sides of the spacers. As shown in FIG. 1B, the end plates 110 each include an end block 110 and an electrode 110B, i.e., an anode on one end plate 110 and a cathode on the other end plate 110. The stack of spacers and membranes includes a plurality of cell pairs 120. As shown in more detail in FIG. 1C, the cell pairs 120 include a concentrating spacer 125, a diluting or diluting spacer 130, and an ion exchange membrane disposed between each concentrating spacer 125 and diluting spacer 130. The ion exchange membranes include an anion exchange membrane 135 that selectively passes anions and a cation exchange membrane 140 that selectively passes cations. Each concentrate spacer 125 has an anion exchange membrane 135 on one side and a cation exchange membrane 140 on the other side. Similarly, each dilute spacer 130 has an anion exchange membrane 135 on one side and a cation exchange membrane 140 on the other side. A plurality of cell pairs 120 such as those shown in FIG. 1C are stacked in sequence to form a spacer and membrane stack 105.

[0091] Each diluent spacer 130 includes a flow path 145 through which the aqueous solution to be purified flows. Each concentrate spacer 125 includes a flow path 145 through which the aqueous solution flows to receive ions removed from the aqueous solution flowing through the diluent spacer's flow path 145 through the anion exchange membrane 135 and the cation exchange membrane 140 between each concentrate spacer 125 and the adjacent diluent spacer 130. The flow paths 145 are typically filled with ion exchange media 200 in the form of anion and / or cation exchange resin beads to facilitate the movement of ions through the flow paths 145. The flow paths 145 are separated by ribs 150 with side walls 150A (see FIG. 2) that define the lateral extent of the flow paths 145. The ribs 150 and their side walls 150A may be considered to define the sides of the flow paths 145, and the anion exchange membrane 135 and the cation exchange membrane 140 may be considered to define the upper and lower portions of the flow paths 145. The same is true for the additional flow paths 145A-145D described below. In some embodiments, the anion exchange membrane 135 may define an upper wall of the flow path of the dilute or concentrate spacer, and the cation exchange membrane 140 may define a lower wall of the flow path of the dilute or concentrate spacer. Alternatively, the anion exchange membrane 135 may define a bottom wall of the flow path of the dilute or concentrate spacer, and the cation exchange membrane 140 may define an upper wall of the flow path of the dilute or concentrate spacer.

[0092] The typical flow paths of the feed and exhaust through the cell pairs are shown in Figure ID. Although the fluid flow directions through the channels 145 of the concentrate spacer 125 and dilute spacer 130 are shown as parallel in Figure 2, in other embodiments, these fluid flow directions can be counter-current.

[0093] 2 further illustrates a pair of spacers, including a concentrate spacer 125 and a diluent spacer 130, with the intervening ion exchange membrane omitted to show inlet and outlet manifolds 155, 160 that fluidly couple the inlets and outlets 165, 170 (also referred to herein as inlet and outlet ports) to the fluid flow path 145. Note that the locations of the manifolds relative to the inlets and outlets may be reversed from the locations shown for either or both of the spacer types.

[0094] EDI devices are typically designed for nominal flow rate, deionization performance, and pressure drop. Increasing the flow rate beyond the nominal flow rate can reduce the capital cost per unit of flow rate. In systems where multiple devices are paralleled to meet a specified flow rate, increasing the flow rate per device reduces the number of devices required, reducing the capital cost of not only the EDI device, but also supporting equipment such as power, piping, instrumentation, and control devices.

[0095] However, increasing the flow rate can result in reduced deionization performance and increased pressure drop, which can cause the EDI system to not meet specifications and performance guarantees.

[0096] One way to increase the flow rate per EDI device is to increase the size of the spacer, thereby increasing the total volume of the flow compartments. For example, the VNX™ EDI device dilution spacer from Evoqua Water Technologies, LLC has an overall diameter of 17 inches (43.2 cm). By increasing the diameter D to 24 inches (61.0 cm), the volume of the dilution compartment (the volume defined by the flow paths) increases accordingly to D. 2 Assuming an increase in flow rate by 1.0 gpm (3.0 lpm), the flow rate per spacer doubles to 1.1 gpm (4.15 lpm) if the residence time remains the same. However, the pressure drop per spacer is greater due to the longer duct path length and higher flow velocity. The forces on the closure mechanism (end blocks, end plates, tie rods) due to internal pressure double, which can complicate structural design and cost.

[0097] Aspects and embodiments disclosed herein include methods and spacer structure modifications to increase flow rates in EDI devices without compromising performance and pressure drop.

[0098] In one embodiment, the EDI spacer comprises at least two sets of flow paths. Each set includes multiple paths that are fed from a common inlet manifold and discharged to a common outlet manifold. The two sets of paths may be fluidly connected in parallel or in series. The size distribution of the ion exchange resin within the paths is selected so that the EDI device meets a specified deionization performance and pressure drop. In some embodiments, the resin diameter is less than 400 μm. In some embodiments, the EDI dilution and / or concentrate spacer flow paths may include anion and cation ion exchange resin beads, each having a bimodal size distribution, and the dilution and concentrate spacers may form a cell pair that exhibits a conductivity at least 20% higher than the conductivity of a cell pair including a dilution and concentrate spacer that includes only uniformly sized anion exchange resin beads and uniformly sized cation exchange resin beads. This may apply to any spacer configuration disclosed herein.

[0099] FIG. 3 shows one embodiment of a high flow EDI spacer set. In each of the concentrate and dilute spacers 125, 130, the flow paths 145 are divided into a plurality of first flow paths 145A and a plurality of second flow paths 145B, as shown in the spacers of FIG. 2. A central manifold 175, also referred to herein as a second manifold 175 or simply manifold 175 to distinguish it from the inlet and outlet flow manifolds 155, 160 (labeled in FIG. 2), is disposed between and in serial fluid communication with the plurality of first flow paths 145A and the plurality of second flow paths 145B. The manifold 175 may include a fluid-permeable wall 175A, e.g., a wall including openings that allow fluid flow between the interior of the manifold 175 and the first and second plurality of flow paths 145A, 145B. The openings in the wall 175A may have a dimension smaller than the average or smallest dimension of the ion exchange resin beads in the plurality of first flow channels 145A and / or the plurality of second flow channels 145B to prevent the resin beads from passing from the flow channels 145A, 145B to the manifold 175. Alternatively, the wall 175A may not be present and the manifold 175 may be defined by an open space between the plurality of first flow channels 145A and the plurality of second flow channels 145B. As shown in FIG. 2, the manifold 175 may be located along the center or diameter of the concentrate spacer 125 and the diluent spacer 130.

[0100] The plurality of first flow channels 145A direct the fluid in a first planar direction parallel to the major plane of the spacers 125, 130 in a portion of the flow path from the inlet port 165 to the outlet port 170 of each spacer. The major plane of the spacer is a plane parallel to the top and / or bottom surface of the spacer. The manifold 175 directs the fluid in a second planar direction parallel to the major plane of the spacers 125, 130 in another portion of the flow path from the inlet port to the outlet port of each spacer. The first and second planar directions may be different or the same. The plurality of second flow channels 145B direct the fluid in a third planar direction parallel to the major plane of the spacers 125, 130 in a portion of the flow path from the inlet port to the outlet port of each spacer. The third planar direction may be different or the same as either the first planar direction or the second planar direction. The positions of the first plurality of channels 145A and the second plurality of channels 145B may be reversed from the positions shown in FIG. 3 for either or both of the spacers 125, 130.

[0101] A portion of the fluid flow through the manifold 175 may be parallel to the direction of fluid flow through the first and / or second flow channels 145A, 145B, for example, when the fluid enters or exits the manifold 175. The fluid is also directed in a planar direction parallel to the major planes of the spacers 125, 130 within the inlet and outlet flow manifolds 155, 160. At least a portion of the fluid flow through the inlet and outlet flow manifolds 155, 160 may be parallel to the longitudinal extension of the first and / or second flow channels 145A, 145B, and another portion of the fluid flow through the inlet and outlet flow manifolds 155, 160 may be parallel to the longitudinal extension of the manifold 175.

[0102] The concentrate and / or diluent spacers 125, 130 may include one or two inlet ports 165 and one or two outlet ports 170. As shown in FIG. 3, any individual port may be either an inlet port 165 or an outlet port 170. Other embodiments may include more inlet and outlet ports. Depending on the port configuration and which ports are inlet or outlet ports, the average flow direction of the fluid through the first and second flow channels 145A, 145B may be toward or away from the manifold 175, as shown for two different spacer port configurations shown in FIGS. 4A and 4B, respectively.

[0103] 4A and 4B are shown with arrows indicating two different additions to the direction of fluid flow through the channels of the diluent spacer 130. It should be understood that similar additions to the direction of fluid flow through the channels of the concentrate spacer 125 are also included in this disclosure. The spacers in FIGS. 4A and 4B, as well as the spacers in the other figures, are shown in a simplified manner that excludes features such as caps and seals.

[0104] In the spacer with the port and fluid flow configuration as shown in FIG. 4A, the first plurality of flow channels 145A is disposed between the manifold 175 and the first inlet port 165. The spacer of FIG. 4A includes a second inlet port 165 on a substantially opposite side of the spacer and opposite the first inlet port 165 of the manifold 175. The second plurality of flow channels 145B is disposed between the manifold 175 and the second inlet port 165. In each spacer, the feed from the two inlet ports enters two sets of flow channels 145A, 145B, which flow in parallel but in opposite directions. The discharge from the flow channels 145A, 145B is collected in the manifold 175 and discharged from a single outlet port 170. The direction of fluid flow through the first plurality of flow channels 145A, or the average flow direction of the fluid, is substantially opposite to the direction of fluid flow through the second plurality of flow channels 145B. This is because the average flow direction of fluid through each of the channels 145A, 145B is from the respective inlet ports 165 toward the centrally located manifold 175. The fluid flow through the channels 145A, 145B may be considered to converge. The average flow direction of fluid through the manifold 175 is substantially perpendicular to the average flow direction of fluid through the first plurality of channels 145A and the average flow direction of fluid through the second plurality of channels 145B. It should be understood that the fluid flow through the channels 145A, 145B, the manifold 175, and other structures described herein with respect to other embodiments may include eddies or vortexes and are not completely laminar, and therefore the term "direction of fluid flow" as used herein should be interpreted as "average direction of fluid flow" unless otherwise specified.

[0105] In some embodiments, the manifold 175 may increase in cross-sectional area, e.g., width, from the end furthest or farthest from the outlet port 170 to the end closest or nearest to the outlet port 170, as shown in FIG. 5. This may allow the manifold 175 to accommodate additional fluid flow as fluid is fed to the manifold 175 from more of the first and second plurality of channels 145A, 145B. Thus, the manifold 175 may include a wall 175A disposed at an acute angle relative to the average flow direction of fluid through the manifold 175, or the manifold 175 may include two walls 175A, each disposed at an acute angle relative to the average flow direction of fluid through the manifold. In other embodiments, the manifold 175 may increase in height from the end furthest or farthest from the outlet port 170 to the end closest or nearest to the outlet port 170 in addition to or instead of increasing in width from the end furthest or farthest from the outlet port 170 to the end closest or nearest to the outlet port 170.

[0106] Referring again to Figures 4A and 4B, the roles of the inlet and outlet ports 165, 170 may be reversed as shown in Figure 4B compared to Figure 4A. In Figure 4B, the spacer includes two outlet ports 170 and one inlet port 165. Fluid flows from the inlet port 165 into the manifold 175 and through the first and second plurality of flow channels 145A, 145B to the first and second outlet ports 170, respectively. In such a configuration, the first plurality of flow channels 145A is disposed between the manifold 175 and the first outlet 170, and the second plurality of flow channels 145B is disposed between the manifold 175 and the second outlet 170. Similar to the inlet ports in Figure 4A, in Figure 4B the first and second outlets 170 are on substantially opposite sides of the spacer and on opposite sides of the manifold 175. The direction of fluid flow through the first plurality of channels 145A is substantially opposite to the direction of fluid flow through the second plurality of channels 145B. This is because fluid flows through both the first and second plurality of channels 145A, 145B from the manifold 175 toward their respective outlets 170. The fluid flow through the first and second plurality of channels 145A, 145B may be considered divergent. The direction of fluid flow through the manifold 170 is substantially perpendicular to the direction of fluid flow through the first plurality of channels 145A and the direction of fluid flow through the second plurality of channels 145B. In some embodiments, in the configuration of FIG. 4B, the manifold 175 may increase in cross-sectional area, e.g., width and / or height, as shown in FIG. 5. The increase in cross-sectional area occurs along a path from the end closer to or closest to the inlet port 165 (the end farther or furthest from the outlet port 170) to the end farther or furthest from the inlet port 165 (the end closer to or closest to the outlet port 170).

[0107] Assuming the overall size of the spacer is maintained the same as current technology spacers, the flow path length per fluid flow path is reduced. For example, the diluent spacer of FIG. 3 (hereafter referred to as the "high flow" spacer) may have fluid flow paths 145A, 145B that are 4.0 inches (10.2 cm) long, as opposed to the 9.1 inch (23.1 cm) long fluid flow path 145 in the diluent spacer of the VNX™ EDI device, i.e., shown in the spacer of FIG. 2. The total volume in the diluent compartment (volume of both sets of paths combined) is 27.53 in. 3 (451.1cm 3 ), which represents 93% of the volume of a VNX™ EDI device spacer. To increase the flow rate per spacer, the residence time in the high flow spacer can be shorter than the residence time in the VNX™ EDI device diluent spacer. Reducing the residence time is generally expected to result in reduced deionization performance, since ionic contaminants have less time to pass vertically through the fluid flow channels 145A, 145B of the diluent spacer 130 and through the anion and / or cation selective membranes 135, 140 into the fluid flow channels 145A, 145B of the adjacent concentrate spacer 125. Methods to combat this effect are described below.

[0108] The embodiment of FIG. 5 described above may address the problem of shorter residence times due to shorter fluid flow path lengths. The ends of each fluid flow path 145A, 145B are not perpendicular to the sides of the fluid flow paths 145A, 145B. The angled fluid flow paths 145A, 145B provide more space for membrane seals, and the tapered manifold 175 reduces changes in flow rate as the effluent from the fluid flow paths 145A, 145B is collected and sent to the outlet port 170. Additionally, as described in more detail below, in the embodiment of FIG. 5, and other embodiments disclosed herein, the size or size distribution of the anion and cation exchange medium beads in the fluid flow paths 145A, 145B of the concentrating and / or diluting spacers 125, 130 may be adjusted, e.g., to reduce the average size, to increase the transport rate of ionic species through the fluid flow paths 145A, 145B of the diluting spacer 130 and into the fluid flow paths 145A, 145B of the concentrating spacer 125.

[0109] FIG. 6 illustrates another embodiment of a diluent spacer 130 that may address the problem of shorter residence times due to shorter fluid flow path lengths. In the spacer of FIG. 6, the multiple fluid flow paths 145A, 145B are configured to vary the rate of fluid flow depending on the distance from the first and second inlet ports 165. Some ionic species may flow from the diluent spacer 130 into the adjacent concentrate spacer 125 at the upstream end of the fluid flow paths 145A, 145B, and the ionic concentration of the fluid may decrease depending on the flow distance through the fluid flow paths 145A, 145B. As the concentration of ionic species in the fluid being treated decreases, the rate of fluid flow may slow depending on the distance through the multiple fluid flow paths 145A, 145B, and the ionic species may take longer to exit the diluent spacer 130 and enter the adjacent concentrate spacer 125. The cross-sectional areas of the first and second multiple flow paths 145A and 145B vary depending on the distance from the first and second inlet ports 165, respectively. The ribs 150 defining the fluid flow channels 145A, 145B increase in height along their respective fluid flow paths, with the thickness or height of the fluid flow channels 145A, 145B varying along the flow paths, being thinnest at the inlet end and thickest at the outlet end. The increased height may be achieved symmetrically about a cross section parallel to the major plane of the spacer, or the height of the ribs may be increased only on the top or bottom side of the spacer 130. The varying cross-sectional area of ​​the fluid flow channels 145A, 145B along the flow paths reduces the flow rate along the flow paths, resulting in greater water splitting and increased contact time between the aqueous solution flowing through the fluid flow channels 145A, 145B and the ion exchange membranes or beads adjacent to or contained within the fluid flow channels 145A, 145B, enhancing removal of SiO2 and other contaminants. The height of the second plurality of flow paths 145B can vary with distance from the second inlet port 165 in the same manner that the height of the first plurality of flow paths 145A varies with distance from the first inlet port 165.

[0110] Similar to the spacers of FIGS. 3-5, the spacer of FIG. 6 includes two inlet ports 165 and a centrally located manifold 175. The manifold 175 is in serial fluid communication with the first plurality of channels 145A between the first inlet port 165 and the outlet port 170, and is configured to direct fluid in a second direction, different from the first direction, through the first plurality of channels 145A in a portion of the flow path from the first inlet port 165 to the outlet port 170. The second plurality of channels 145B is located between the manifold 175 and the second inlet port 165. The manifold 175 is in serial fluid communication with the second plurality of channels 145B between the second inlet port 165 and the outlet port 170, and is configured to direct fluid in a second direction, different from the first direction, through the second plurality of channels 145B in a portion of the flow path from the first inlet port 165 to the outlet port 170.

[0111] To provide a concentrate spacer, for example, where the top surface of the concentrate spacer is disposed on the bottom surface of the dilute spacer, and to properly mate with the dilute spacer when the dilute spacer has ribs of varying height along the flow path, as shown in FIG. 6, the concentrate spacer 125 may include a third plurality of channels 145C and / or a fourth plurality of channels 145D having dimensions complementary to the dimensions of the first plurality of channels 145A and / or the second plurality of channels 145B of the dilute spacer 130. An example of such a concentrate spacer is shown in FIG. 7. As shown in FIG. 7, the height of the ribs 150 of the concentrate spacer 125 decreases with the distance from the outer region of the spacer to the inner region of the spacer, so that they can mate with the ribs 150 of the dilute spacer 130 of FIG. 6 with little or no gap between them, with the ion exchange membrane interposed therebetween. The thickness of the concentrate compartment also varies, but in the opposite direction to the dilute compartment, so that the dilute and concentrate spacers may be stacked without leaving any gaps between their respective ribs.

[0112] As generally described above, one or more of the first plurality of flow paths, the second plurality of flow paths, the third plurality of flow paths, or the fourth plurality of flow paths 145A-145D may each include beads of anion and cation exchange resin having a bimodal size distribution. The diluent spacer 130 and the concentrate spacer 125 may form a cell pair that exhibits a conductivity at least 20% higher than the conductivity of a cell pair including the diluent spacer 130 and the concentrate spacer 125 that each include only uniformly sized anion exchange resin beads and uniformly sized cation exchange resin beads.

[0113] In addition to or instead of increasing the cross-sectional area along the flow path by increasing the height with distance from the inlet port 165, the first and / or second plurality of fluid flow paths 140A, 140B may increase in width along the flow path with distance from the inlet port 165. This also reduces the fluid flow rate with distance through the fluid flow paths 140A, 140B, increases the residence time, and reduces the concentration of ionic species in the fluid being processed, thereby increasing the time for the ionic species to be evacuated from the dilution spacer. As shown in FIG. 8, this may be achieved by making the walls 150 of the first and / or second plurality of flow paths 140A, 140B non-parallel. The walls 150 of the first and / or second plurality of flow paths 140A, 140B are angled and divergent with respect to each other, so that the width of the first and / or second plurality of flow paths 140A, 140B increases with distance from the inlet port 165. This change in width of the fluid flow paths with distance reduces the fluid flow rate and increases the surface area of ​​the ion exchange membranes 135, 140 adjacent to the fluid flow paths 145A, 145B with distance from the inlets of the fluid flow paths 145A, 145B. Both of these factors can increase the transport of ionic contaminants from the dilute spacer 130 to the concentrated spacer 125.

[0114] In other embodiments, the cross-sectional area of ​​the first and / or second plurality of fluid flow paths 145A and / or the second plurality of fluid flow paths 145B may remain substantially the same as a function of distance from the first and / or second inlet port 165, and at least one of the width or height of the first and / or second plurality of fluid flow paths 145A, 145B may vary as a function of distance from the first and / or second inlet port 165. For example, if the width of the fluid flow paths 145A, 145B increases as a function of distance from the inlet of the flow path, the advantage of increasing the area of ​​the ion exchange membrane adjacent to the fluid flow paths 145A, 145B may still be obtained. Thus, even if the flow rate of the fluid along the fluid flow paths 145A, 145B remains substantially constant, ion transport from the diluent spacer 130 to the concentrate spacer 125 may be enhanced as a function of distance along the fluid flow paths 145A, 145B.

[0115] It has been found that when a dilution spacer is provided with multiple flow paths 145A and the aqueous solution to be purified flows in parallel, some of the flow paths may exhibit different flow resistances than the other flow paths, resulting in different residence times of the aqueous solution in different flow paths of the multiple flow paths 145A. This may result in different amounts of contaminants being removed from the aqueous solution in different flow paths. For example, one of the multiple flow paths 145A may contain non-uniformly compressed ion exchange resin beads, providing channeling through the flow path, resulting in a shorter residence time than in the other of the multiple flow paths 145A, and thus a shorter time required to purify the aqueous solution. In a system in which two stages of processing through flow paths arranged in series are performed, it may be desirable to mix the aqueous solutions output from the first of the multiple parallel flow paths 145A to reduce the concentration of impurities in the aqueous solution that was not purified as thoroughly in one of the flow paths as in the other flow paths in the mixed solution before further processing in the downstream fluid flow paths. A spacer that allows mixing of the aqueous solutions output from the parallel fluid flow paths is shown in FIG. 9. In the spacer of FIG. 9, an aqueous solution or fluid to be treated (also called feed water) is introduced into a first plurality of flow paths 145A arranged in parallel through an inlet port 165 via an inlet manifold 155 and passes through the first plurality of flow paths 145A. A mixing zone 180 is fluidly disposed between the first plurality of flow paths 145A and the second plurality of flow paths 145B. The mixing zone 180 is configured to receive fluid from each of the first plurality of flow paths 145A and direct the fluid to each of the second plurality of flow paths 145B. The treated fluid is then directed through an outlet manifold 160 and collected at an outlet port 170. The mixing zone 180 distributes the partially treated fluid from each of the first plurality of flow paths 145A to each of the second plurality of flow paths 145B. This embodiment does not increase the flow rate per spacer, but does improve deionization performance in a "two-pass" process. With proper size and resin selection, the deionization performance of each pass (flow through one set of channels) is comparable to that of current technology dilute spacers. Furthermore, remixing the output from the first pass can reduce pass-to-pass deionization variability and improve deionization in the second pass.

[0116] The mixing zone 180 has at least one wall 180A disposed between the first plurality of flow channels 145A and the second plurality of flow channels 145B. The wall 180A has a plurality of openings 180B configured to disrupt the laminar flow and promote mixing of the fluids in the mixing chamber 180. The mixing zone 180 may include one wall 180A defining a downstream end of the first plurality of flow channels chamber 145A. The first plurality of flow channels 145A may include beads of ion exchange resin, and the plurality of openings 180B in the wall 180A defining the downstream end of the first plurality of flow channels 145A may have dimensions smaller than the beads of ion exchange resin to prevent the beads of ion exchange resin from migrating from the first plurality of flow channels 145A to the mixing zone 180. The mixing chamber 180 may include an internal structure 180C, such as a pillar or a baffle, configured to promote mixing of the fluids introduced into the mixing chamber 180 from the first plurality of flow channels 145A.

[0117] The mixing chamber 180 may further include a second wall 180A disposed between the first plurality of flow paths 145A and the second plurality of flow paths 145B. The second wall 180A may have a second plurality of openings 180B. The second wall 180A may define an upstream end of the second plurality of fluid paths 145B. The second plurality of flow paths 145B may include ion exchange resin beads, and the second plurality of openings 180B may have dimensions smaller than the ion exchange resin beads to prevent the ion exchange resin beads from migrating from the second plurality of flow paths 145B to the mixing zone 180. The openings 180B of the second wall 180A may slow the flow of fluid from the mixing zone 180 to facilitate mixing of the effluent from the first plurality of flow paths 145A and more evenly distribute the mixed effluent to each of the second plurality of flow paths 145B.

[0118] 9, the first and second plurality of channels 145A and 145B are equal in number, each of the first and second plurality of channels 145A is aligned with a corresponding one of the second plurality of channels 145B, and the first and second plurality of channels 145A and 145B have substantially the same dimensions. The term "substantially the same" as used herein with respect to the dimensions of the channels 145A, 145B may mean the same except for differences due to variability inherent in the spacer manufacturing process. In other embodiments, the first and second plurality of channels 145A and 145B may differ in number, may be misaligned, or may have different dimensions.

[0119] The direction of fluid flow through the first plurality of flow channels 145A may be substantially parallel to the direction of fluid flow through the second plurality of flow channels 145B. As used herein, the term "substantially parallel" with respect to the direction of fluid flow through the flow channels may mean parallel except for deviations due to pressure differences associated with the arrangement of the inlet ports 155 and the outlet ports 160 or other asymmetries of the spacer. The rate of fluid flow through the first plurality of flow channels 145A may be substantially the same as the rate of fluid flow through the second plurality of flow channels 145B, subject to differences resulting from, for example, pressure differences associated with the arrangement of the inlet ports 155 and the outlet ports 160 or other asymmetries of the spacer. In other embodiments, the rate of fluid flow through the second plurality of flow channels 145B may be slower than the rate of fluid flow through the first plurality of fluid flow channels 145A, providing a longer residence time for removing ionic impurities from the fluid in the second plurality of flow channels 145B. This may be beneficial because the fluid flowing through the second plurality of fluid flow paths 145B may have a lower concentration of ionic impurities than the fluid flowing through the first plurality of fluid flow paths 145A. This reduction in velocity may be achieved by increasing the cross-sectional area of ​​the second plurality of fluid flow paths 145B relative to the first plurality of fluid flow paths 145A. For example, this may be achieved by forming the second plurality of fluid flow paths 145B to have a wider width or a greater height than the first plurality of fluid flow paths 145A.

[0120] The mixing zone 180 may have a narrower width in the direction of average fluid flow through the mixing zone 180 than the width of the first plurality of channels 145A and / or the second plurality of channels 145B in a direction perpendicular to the direction of average fluid flow through the first plurality of channels 145A and / or the second plurality of channels 145B. The width of the mixing zone 180 may be substantially constant over the length of the mixing zone 180, subject to differences in width due to variability inherent to the manufacturing process of the spacer, for example. The mixing zone 180 may have a longer length in the direction perpendicular to the direction of average fluid flow through the mixing zone 180 than the length of the first plurality of channels 145A and / or the second plurality of channels 145B in the direction of average fluid flow through the first plurality of channels 145A and / or the second plurality of channels 145B. The length of the mixing zone 180 may be substantially constant over the width of the mixing zone 180, subject to differences in length due to variability inherent to the manufacturing process of the spacer, for example.

[0121] EDI devices may be used for general deionization, e.g., deionizing feed water with a conductivity of 50-100 μS / cm to a product with a conductivity of 1-10 μS / cm. In normal practice, strongly dissociated ions are removed near neutral pH. Ion movement across the compartment under an applied DC field is assumed to occur primarily along the surfaces of the ion exchange resins and not within the resin or interstitial fluids between the resins.

[0122] However, most implementations of EDI devices are aimed at producing ultrapure water with resistivity up to >18MΩ-cm. Dissolved boron, silica, and weak acids such as CO2 are removed. Particle diffusion within the resin becomes an important transport mechanism, Use of low cross-linked resin beads and membranes; The inhomogeneous membrane increases the local current on the membrane surface, which increases the local water splitting and generates a local pH shift. A mixture of strong and weak ion exchange resins, and / or Addition of Type II anion resin, This can be promoted in such a way.

[0123] One way to maintain deionization performance at higher flow rates is to use a smaller diameter resin than the current state-of-the-art dilute spacers, thereby increasing the total surface area of ​​the resin beads in the spacer compared to the current state-of-the-art spacers. The equation for estimating the surface area ratio of the high flow spacers disclosed herein to the VNX™ EDI device spacers is:

[0124]

number

[0125] ε = packing density = fraction of duct volume occupied by resin (e.g., 0.64 for dense random packing), V = volume in the tract, N = number of resin beads in the tract; r = average radius of the beads, S = surface area of ​​each bead.

[0126] The suffix 1 represents the current VNX™ EDI device spacer, The suffix 2 represents a high flow spacer.

[0127] Assuming the resin size distribution is uniform, In the current VNX™ EDI device module, the diameter is 600 μm. In the high flow design concept, it is 250 μm.

[0128] and ε1=ε2.

[0129] V1=29.68in 3 (486.4cm 3 ), V2=27.53in 3 (451.1cm 3 ).

[0130]

number

[0131] Doubling the total surface area of ​​resin beads does not automatically double the flow rate. It does increase the flow rate. The percentage increase can be determined experimentally because not all available resins have a uniform size distribution and resin properties vary from one resin type to another.

[0132] Smaller resins will have a higher pressure drop per unit length of fluid flow path, but the length of the fluid flow path in the high flow spacers disclosed herein may be shorter than in VNX™ EDI device module spacers, so the overall pressure drop per spacer may not change significantly. Also, the pressure drop characteristics of the high flow spacers may be determined experimentally.

[0133] A cylinder packed with spherical ion exchange resin beads of uniform diameter has the highest local wall porosity and the lowest resistance to fluid flow. Fluid to be deionized will therefore preferentially flow across the membrane surface, bypassing the bulk resin bed. This "wall effect" can reduce deionization performance. The distance the wall effect extends from the wall varies with the type of packing (from hexagonal close packing to random packing) and is usually on the order of a few bead diameters. The percentage of the total flow that bypasses the bulk resin bed is lowest for resin beds with the smallest diameter resin.

[0134] In EDI devices, the resin is packed between parallel flat walls (membranes). The smaller the ion exchange resin beads, the less the effect of the walls.

[0135] However, for a constant number of beads in the spacer fluid flow paths between the membranes, the relative porosity is likely to be roughly the same for large and small beads, with the smaller beads having the advantage of thinner boundary layers (both in fluid flow and diffusion). As long as the water is split in the membrane (especially for heterogeneous membranes) and the void size is reduced by using smaller beads, it does no harm to have more flow along the membrane surface.

[0136] In mixed beds of cation and anion resins, narrower spacing between the membranes may be advantageous because increasing the number of beads between the membranes beyond three increases the frequency of dead-ends in current transport across the beads.

[0137] The fluid flow channels within the spacer of the EDI device can be filled with a resin with a bimodal size distribution. The diameter can be chosen so that the smaller diameter beads fit between the interstices of the larger beads. Increasing the packing density and surface area of ​​the resin beads per unit volume; Improving electrical conductivity within the resin bed; 3. Allowing for larger intermembrane distances without hitting bead restrictions, and Reducing the wall effect of the membrane; It is.

[0138] In some embodiments, the performance of the EDI device, e.g., reducing liquid channeling and wall effects, and improving the conductivity of the resin bed in the fluid flow paths of the EDI device spacer, can be achieved by selecting the distribution of resin bead sizes in the fluid flow paths. Such performance improvements can be implemented in any of the embodiments of the EDI device spacer disclosed herein. Such performance improvements can be implemented, for example, in an electrodeionization device including a spacer comprising an inlet port, an outlet port, a first plurality of flow paths configured to direct fluid along a portion of the fluid flow path from the inlet port to the outlet port, and a second plurality of flow paths configured to direct fluid along a second portion of the fluid flow path from the inlet port to the outlet port. The second plurality of flow paths can be in series with the first plurality of flow paths, e.g., in the embodiment shown in FIG. 9. The second plurality of flow paths can be configured to flow fluid in a direction opposite to the direction of fluid flow through the first plurality of flow paths, e.g., in the embodiment shown in FIGS. 4A-6 and FIG. 8.

[0139] Ion exchange media beads are disposed within each of the first and second plurality of flow paths, and a size distribution of the ion exchange media beads can vary from the inlet to the outlet of the first plurality of flow paths, from the inlet to the outlet of the second plurality of flow paths, or from the first plurality of flow paths to the second plurality of flow paths.

[0140] The ion exchange media beads may form a mixed bed including cation exchange media beads and anion exchange media beads. In some embodiments, the cation exchange media beads have a different size distribution than the anion exchange media beads, e.g., a size distribution having a different mean, median, or variance. The first plurality of flow paths or the second plurality of flow paths may include a different number ratio of cation exchange media beads to anion exchange media beads. Either or both of the first plurality of flow paths or the second plurality of flow paths may include substantially the same total surface area of ​​cation exchange media beads and anion exchange media beads. It is to be understood that the term "substantially the same" used with respect to the comparison of the total surface area of ​​cation exchange media beads and anion exchange media beads means that the total surface area of ​​the two types of ion exchange beads may differ even if the same total surface area is intended due to variations inherent in the manufacturing process of the spacer and EDI device. In other embodiments, the mixed bed of ion exchange resin beads in either or both of the first or second plurality of flow paths in an EDI device spacer disclosed herein may include substantially equal numbers of cation and anion exchange media beads (same number subject to manufacturing variability) or substantially equal volumes of cation and anion exchange media beads (same volume subject to manufacturing variability).

[0141] As shown in Figure 10, one of the first plurality of flow paths or the second plurality of flow paths may include cation exchange media beads having a first packing density and anion exchange media beads having a second packing density different from the first packing density. In some embodiments, the cation exchange media beads have a higher packing density than the anion exchange media beads, and in other embodiments, the anion exchange media beads have a higher packing density than the cation exchange media beads. In further embodiments, the anion exchange media beads and the cation exchange media beads in the fluid flow paths of the EDI device spacer may have substantially the same packing density, depending on manufacturing variations.

[0142] One of the first plurality of flow paths or the second plurality of flow paths may include cation exchange media beads having a first monomodal size distribution with a first median size and anion exchange media beads having a second monomodal size distribution with a second median size different from the first median size. The term monomodal size distribution as used herein refers to a size distribution having a mean or median value and a spread of sizes related to, for example, manufacturing variations. The two monomodal size distributions may be Gaussian, for example, as shown in FIG. 11, but the size distributions may deviate from a perfect Gaussian distribution or may be of different distribution types, and the total number, total surface area, and / or total volume of different resin types may be the same or different. In other embodiments, the size distributions of the anion exchange media beads and the cation exchange media beads may be substantially the same, although subject to manufacturing variations.

[0143] In some embodiments, the first or second plurality of flow paths may include cation exchange media beads and / or anion exchange media beads having a bimodal size distribution. As used herein, a bimodal resin bead size distribution means that the resin beads include two groups, one having a first mean or median size and size distribution, and the other having a second mean or median size and size distribution, as shown in Figure 12. The size distribution may be distorted from a perfect Gaussian distribution, and the distribution type may be different, and the total number, total surface area, and / or total volume of the different resin size groups may be the same or different.

[0144] The cation exchange media beads and anion exchange media beads in the first and / or second plurality of flow paths may collectively increase in volume and the void volume in the first and / or second plurality of flow paths may decrease by at least 5%, or in other embodiments by at least 2% or at least 10%, during use of the electrodeionization device compared to when they were initially packed into the first and / or second plurality of flow paths.

[0145] In some embodiments, the cation exchange medium beads can have larger beads having substantially the same size and smaller beads having substantially the same size, also shown diagrammatically in Figure 12. As used herein, the term "substantially the same size" resin beads refers to a size distribution of resin beads having a single mean or median and a spread of sizes associated with, for example, manufacturing variations.

[0146] The first and second plurality of flow paths may be arranged in series, for example as shown in FIG. 8, and the average size of the ion exchange media beads may decrease with distance along the flow path through the first and second plurality of flow paths, as shown generally in FIG. 13A and FIG. 13B. This may increase the rate of ion transport from the dilute spacer flow paths to the concentrate spacer flow paths, compensating for the decrease in ion concentration of the fluid being processed with distance through the dilute spacer fluid flow paths. The average size of the ion exchange media beads may smoothly decrease with distance along the flow path through the first and second plurality of flow paths, as shown generally in FIG. 13A, or may include a step function when transitioning from the first plurality of flow paths to the second plurality of flow paths, as shown generally in FIG. 13B. The second plurality of flow paths may be arranged downstream of the first plurality of flow paths, and the average size of the ion exchange media beads may be smaller in the second plurality of flow paths than in the first plurality of flow paths. The average size of the ion exchange media beads can decrease with distance along a flow path through one of the first plurality of flow channels or the second plurality of flow channels, as shown diagrammatically in FIG. 13A.

[0147] The packing density of the ion exchange media beads may vary, for example, increasing from the inlet to the outlet of the first plurality of flow paths, as shown generally in FIG. 14A. The packing density of the ion exchange media beads may vary, for example, increasing from the inlet to the outlet of the second plurality of flow paths, as shown generally in FIG. 14A. The packing density of the ion exchange media beads may vary, for example, increasing from the first plurality of flow paths to the second plurality of flow paths, as shown generally in FIG. 14B. The change in packing density may be continuous or stepwise, and the packing density may increase or decrease. These packing density changes may increase the rate of ion transport from the flow paths of the dilute spacer to the flow paths of the concentrate spacer, compensating for the decrease in ion concentration of the fluid being processed as a function of distance through the fluid flow paths of the dilute spacer. In other embodiments where it is desirable to decrease the flow resistance as a function of the length of the flow path or the length of the first and second plurality of flow paths arranged in series, the ion exchange resin bead packing density may decrease as a function of distance through one or both of the first and second plurality of flow paths.

[0148] The packing density of the ion exchange media beads may be higher near the walls of one of the first or second plurality of flow channels than near the central region near the walls, as shown diagrammatically in FIG. 15. The walls may be walls 150A of ribs 150 separating the flow channels, or may be membranes 135, 140 at the top or bottom of the flow channels. This may prevent wall effects that lead to fluid guiding through the flow channels near the walls. In some embodiments, the anion and cation exchange resin beads near the walls of the first and / or second plurality of first flow channels may be smaller in average size than the anion and cation exchange resin beads near the center of the first and / or second plurality of first flow channels and farther from the walls of the first and / or second plurality of first flow channels, facilitating an increased packing density near the walls.

[0149] 8, in an EDI device including a mixing zone, a first plurality of flow paths 145A may include anion and cation exchange resin beads having a larger average size than the anion and cation exchange resin beads included in a second plurality of flow paths 145B. The first plurality of flow paths 145A may include anion and cation exchange resin beads each having a unimodal size distribution. The second plurality of flow paths 145B may include anion and cation exchange resin beads each having a bimodal size distribution.

[0150] In some embodiments, in any of the spacers disclosed herein, one of the first plurality of channels 145A or the second plurality of channels 145B may include a layer of only cation exchange resin, a layer of only anion exchange resin, and a layer of mixed anion and cation exchange resin. The ion exchange media beads may be stacked in layers along the direction of fluid flow through the channel. This is shown diagrammatically in FIG. 16. In different embodiments, the different layers may occur in different orders along the flow path through the channel, and the layers may have the same or different widths along the flow path.

[0151] In various embodiments disclosed herein, the anion exchange membrane 135 and / or cation exchange membrane 140 (collectively referred to as ion exchange membranes 135, 140) disposed between adjacent spacers may include surface features that increase the surface area of ​​the membrane and / or allow the ion exchange membrane beads to be more uniformly or more densely packed against the surface of the ion exchange membrane. These features may include protrusions, recesses, or ribs. Such ion exchange membranes may be referred to herein as profiled ion exchange membranes. Profiled ion exchange membranes 135, 140 may be used in any of the embodiments disclosed herein. Compared to ion exchange membranes with flat surfaces, the increased surface area of ​​the irregular ion exchange membrane may increase ion transport to and through the membrane. Thus, the irregular ion exchange membrane may increase the rate at which ionic contaminants are transported from the fluid in the flow path of the dilute spacer to the fluid in the flow path of the concentrate spacer.

[0152] An example of a portion of the irregular ion exchange membrane 135, 140 is shown in FIG. 17A. The irregular ion exchange membrane includes a plurality of protrusions in the form of partial spheres 210 extending from its surface 205. In some embodiments, the partial spheres, or other surface features described herein, may be present on both sides of the irregular ion exchange membrane. The partial spheres 210 are shown arranged in a regular array, but in other embodiments, the partial spheres may be arranged in an irregular or random distribution. As shown in FIG. 17B, in addition to increasing the surface area of ​​the irregular ion exchange membrane 135, 140, the partial spheres 210 fill the gaps between the beads of ion exchange resin 215 and the irregular ion exchange membrane 135, 140. This may increase the rate of ion transport from the ion exchange resin beads 215 to the irregular ion exchange membrane 135, 140 due to an increased contact area between the ion exchange resin beads 215 and the irregular ion exchange membrane 135, 140.

[0153] The partial spheres 210 may have dimensions of about 0.18D in height and 0.5D in radius, where D is the average or median diameter of the beads of ion exchange resin 215 in the EDI spacer fluid flow chamber that face the surface 205 of the contoured ion exchange membranes 135, 140, as shown in Figure 17C. The partial spheres 210 may be spaced apart such that the centers of the partial spheres 210 lie at the vertices of an equilateral triangle with center-to-center distance = D, as shown in Figure 17D.

[0154] In another embodiment shown in FIG. 17E, the protrusions on the surface of the irregular ion exchange membrane 135, 140 are in the form of pillars 220 with rounded tops. The rounded tops of the pillars 220 may have a radius comparable or equal to some or all of the ion exchange resin beads in the fluid flow chamber that the irregular ion exchange membrane 135, 140 surface faces, or a radius comparable to the average or median radius of the ion exchange resin beads. The pillars 220 may be spaced apart to promote hexagonal packing of the beads of ion exchange resin 215 on the surface 205 of the irregular ion exchange membrane 135, 140, as shown in FIG. 17F. This may maximize the packing density of the beads of ion exchange resin 215 on or near the surface 205 of the irregular ion exchange membrane 135, 140 and / or throughout the fluid flow chamber that the irregular ion exchange membrane 135, 140 surface faces. The pillars 220 may also fill the gaps between the first layer of ion exchange resin beads 215 and the irregular ion exchange membranes 135, 140, as shown in Figure 17G. This may increase the contact area between the ion exchange resin beads 215 and the irregular ion exchange membranes 135, 140, thereby increasing the rate of ion transport from the ion exchange resin beads 215 to the irregular ion exchange membranes 135, 140. Once the first layer of ion exchange resin beads 215 adopts a hexagonal close-packed arrangement, an additional layer of ion exchange resin beads 215' deposited on the first layer also adopts a hexagonal close-packed arrangement, as shown in Figure 17H.

[0155] The pillars 220 may have a height dimension of about D with a radius of 0.5D at the rounded top of the pillars, where D is the average or median diameter of the beads of ion exchange resin 215 in the EDI spacer fluid flow chamber that face the surface 205 of the contoured ion exchange membrane 135, 140, as shown in Figure 171. The pillars 220 may be spaced such that the centers of the pillars 220 are at the vertices of an equilateral triangle with center-to-center distance = 2D, as shown in Figure 17J.

[0156] In another embodiment shown in FIG. 17K, the irregular ion exchange membrane 135, 140 may include a plurality of recesses 225. The recesses 225 may have a radius comparable or equal to some or all of the ion exchange resin beads 215 in the fluid flow chamber facing the surface of the irregular ion exchange membrane 135, 140, or a radius comparable or equal to the average or median radius of the ion exchange resin beads. The recesses 225 may be spaced apart from one another to promote hexagonal packing of the ion exchange resin beads 215 on the surface 205 of the irregular ion exchange membrane 135, 140, as shown in FIG. 17L. This may maximize the packing density of the ion exchange resin beads 215 on or near the surface 205 of the irregular ion exchange membrane 135, 140 and / or throughout the fluid flow chamber facing the surface of the irregular ion exchange membrane 135, 140. As shown in FIG. 17M, embedding the resin beads 215 into the membrane surface 205 reduces the flow gap between the beads 215 and the membrane 135, 140 and increases the contact area between the ion exchange resin beads 215 and the irregular ion exchange membrane 135, 140, which can increase the rate of ion transport from the ion exchange resin beads 215 to the irregular ion exchange membrane 135, 140.

[0157] The recesses 225 have a depth of about 0.25D and a radius of 0.5D, where D is the average or median diameter of the beads of ion exchange resin 215 in the EDI spacer fluid flow chamber that face the surface 205 of the contoured ion exchange membrane 135, 140, as shown in Figure 17N. The recesses 225 may be spaced apart such that the centers of the recesses 225 lie at the vertices of an equilateral triangle with center-to-center distance = D, as shown in Figure 17O.

[0158] In various embodiments, to achieve the same deionization performance, the flow rate per spacer can be increased with increasing applied current. If the electrical resistance between the membrane and the ion exchange medium is unchanged, increasing the current will be accompanied by an increase in the DC voltage applied between the electrodes, and therefore energy consumption may increase.

[0159] One way to mitigate the effects of increased current is to reduce the electrical resistance of the membrane by using thinner membranes. For example, reducing the thickness of an extruded heterogeneous membrane from 0.02 in. (0.051 cm) to 0.014 in. (0.036 cm) reduces the overall resistance of an LX™ EDI device manufactured by Evoqua Water Technologies by 25%.

[0160] The aspects and embodiments disclosed herein are not limited to electrodialysis devices. Many electrochemical separation devices can benefit from the features and methods disclosed herein. Electrochemical separation devices include, but are not limited to, electrodialysis, electrodialysis reversal, continuous deionization, continuous electrodeionization, electrodeionization, electrodialysis, and capacitive deionization. Other electrochemical devices that can benefit from the features and methods disclosed herein include flow batteries, fuel cells, electrochlorination cells, and caustic chlorine cells.

[0161] The phrases and terms used herein are for purposes of description and not limitation. The term "plurality" as used herein refers to two or more items or components. The terms "comprise," "include," "carry," "have," "contain," and "involve," whether in the written description or in the claims or otherwise, are open-ended terms, i.e., meaning "including, but not limited to." Thus, the use of such terms encompasses the items listed thereafter, and their equivalents, as well as additional items. With respect to the claims, only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed transitional phrases, respectively. The use of ordinal numbers such as "first," "second," and "third" to modify elements of a claim does not, in and of itself, imply that the element of a claim has priority, precedence, or order over elements of other claims, or the chronological order in which the actions of a method are performed, but is merely used as a label to distinguish an element of a claim having a particular name from another element having the same name (other than the use of the ordinal number) and to distinguish the elements of the claim.

Claims

1. 1. An electrochemical device comprising a spacer, a first inlet port; a first outlet port; a first plurality of flow channels configured to direct fluid in a first planar direction parallel to a major plane of the spacer in a portion of a flow path from the first inlet port to the first outlet port; a manifold in serial fluid communication with the first plurality of flow paths between the first inlet port and the first outlet port, the manifold configured to direct fluid in a second planar direction parallel to a major plane of the spacer, different from the first planar direction, in another portion of the flow path from the first inlet port to the first outlet port; 1. An electrochemical device comprising a spacer comprising:

2. an inlet manifold in serial fluid communication between the first inlet port and the first plurality of flow channels, the inlet manifold configured to direct fluid in a third planar direction parallel to a major plane of the spacer and different from the first and second planar directions; an outlet manifold in serial fluid communication between the first outlet port and the first plurality of flow channels, the outlet manifold configured to direct fluid in the third planar direction; The electrochemical device of claim 1 further comprising:

3. The electrochemical device of claim 2 , wherein the manifold is disposed along a diameter of the spacer.

4. The electrochemical device of claim 2 , wherein the first plurality of flow paths are disposed between the manifold and the first inlet.

5. The electrochemical device of claim 1 , further comprising a second inlet.

6. The electrochemical device of claim 5 , wherein the second inlet is on a substantially opposite side of the spacer from the first inlet.

7. The electrochemical device of claim 5 , wherein the second plurality of flow paths are disposed between the manifold and the second inlet.

8. 8. The electrochemical device of claim 7, wherein a direction of fluid flow through the first plurality of flow channels is substantially opposite a direction of fluid flow through the second plurality of flow channels.

9. 8. The electrochemical device of claim 7, wherein a direction of fluid flow through the manifold is substantially perpendicular to a direction of fluid flow through the first plurality of flow channels and a direction of fluid flow through the second plurality of flow channels.

10. 5. The electrochemical device of claim 1, wherein the manifold includes a wall disposed at an acute angle relative to a mean direction of fluid flow through the manifold.

11. 11. The electrochemical device of claim 10, wherein the manifold includes two walls each oriented at an acute angle relative to an average direction of fluid flow through the manifold.

12. 5. The electrochemical device of claim 4, wherein the manifold increases in cross-sectional area from the end furthest from the first outlet port to the end closest to the first outlet port.

13. 13. The electrochemical device of claim 12, wherein the width of the manifold increases from the end furthest from the first outlet port to the end closest to the first outlet port.

14. The electrochemical device of claim 3 , wherein the first plurality of flow paths are disposed between the manifold and the first outlet.

15. The electrochemical device of claim 14 further comprising a second outlet.

16. 16. The electrochemical device of claim 15, wherein the second outlet is on a substantially opposite side of the spacer from the first outlet.

17. 16. The electrochemical device of claim 15, wherein the second plurality of flow paths are disposed between the manifold and the second outlet.

18. 20. The electrochemical device of claim 17, wherein a direction of fluid flow through the first plurality of flow channels is substantially opposite a direction of fluid flow through the second plurality of flow channels.

19. 20. The electrochemical device of claim 17, wherein a direction of fluid flow through the manifold is substantially perpendicular to a direction of fluid flow through the first plurality of flow channels and a direction of fluid flow through the second plurality of flow channels.

20. 15. The electrochemical device of claim 14, wherein the manifold increases in cross-sectional area from the end furthest from the first outlet port to the end closest to the first outlet port.

21. 21. The electrochemical device of claim 20, wherein the manifold increases in width from the end furthest from the first outlet port to the end closest to the first outlet port.

22. 10. The electrochemical device of claim 1 comprising an electrodeionization device, wherein the first plurality of first flow channels each contain beads of anion and cation exchange resin having a bimodal size distribution.

23. 23. The electrochemical device of claim 22, wherein the beads of anion and cation exchange resin near the walls of the first plurality of first flow channels have a smaller average size than the beads of anion and cation exchange resin near the center of the first plurality of first flow channels and farther from the walls of the first plurality of first flow channels.

24. 23. The electrochemical device of claim 22, wherein the manifold includes openings of a size smaller than the size of the beads of ion exchange resin.

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