US20130341201A1

US20130341201A1 - Parallel cell electrochemical production of modified anolyte solution

Info

Publication number: US20130341201A1
Application number: US13/568,506
Authority: US
Inventors: Scott D. McCormick; Christopher Wilker; Jacob Abitboul; Chen Boker; David Sheffer
Original assignee: Proteus Solutions LLC
Current assignee: Washing Systems LLC
Priority date: 2012-06-21
Filing date: 2012-08-07
Publication date: 2013-12-26
Also published as: WO2013191717A1

Abstract

A membrane-based electrochemical cell produces a first anolyte solution and a membrane-less electrochemical cell produces a bleach solution such as from a brine solution. The first anolyte solution and bleach solution are combined to form a modified anolyte solution. A dual electrochemical cell device includes two segments, one having a membrane-based electrochemical cell and the other having a membrane-less electrochemical cell, separated by a partition, and secured together into a single, unitary structure.

Description

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 61/662,912 filed Jun. 21, 2012, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention generally relates to production of anolyte solutions with electrochemical cells.

BACKGROUND

Electrochemical cells typically include an anode, a cathode, and a membrane therebetween. When the anode and cathode are powered, anolyte solution is produced in an anolyte space between the anode and the membrane. Catholyte solution may also be produced in a catholyte space between the membrane and the cathode. In such typical electrochemical cells a liquid, such as a brine solution, is coupled into the anolyte space to produce anolyte solution when the anode and cathode are powered. Pure water is advantageously coupled into the catholyte space, although brine solution could also be coupled into that space instead. Alternatively, pure water may be coupled into the anolyte space and brine solution coupled into the catholyte space.
The anolyte solution, and often the catholyte solution, produced by such membrane-based electrochemical cells have been considered to provide cleaning capabilities such as for laundry, clean-in-place, and surface cleaning purposes. But the anolyte solution produced thereby is usually a low pH acid, which can be corrosive, may have free chlorine which might gas off, and may not be sufficiently stable in storage.

SUMMARY OF THE INVENTION

The present invention, in one aspect, provides a system and method for producing a modified anolyte solution possessing desirable cleaning capabilities, but without the drawbacks of the anolyte solutions produced by typical electrochemical cells. To that end, and in accordance with one feature of the present invention, a membrane-less electrochemical cell is provided to produce a bleach solution from brine solution with the bleach solution combined with anolyte solution from a membrane-based electrochemical cell to produce a modified anolyte solution. In particular, a membrane-less electrochemical cell is characterized in that it has an anode, a cathode, and a fluid space, such as a bleach space, therebetween uninterrupted by a membrane so as to produce bleach solution from brine solution in the bleach space when the anode and cathode thereof are powered.
The modified anolyte solution obtained by mixing the bleach solution from the membrane-less cell with the anolyte solution from the membrane-based cell is still acidic and provides desirable cleaning characteristics. But, unlike the anolyte solution produced by the membrane-based cell, the modified anolyte solution has a higher pH and so is less corrosive, reduces the off-gassing, and is more stable for storage.
The membrane-less cell and the membrane-based cell may be fluidically coupled as appropriate to sources of liquid, such as pure water and/or brine solution, and to each other to mix the anolyte solution and bleach solution to produce the modified anolyte solution. The anolyte space of the membrane-based cell and the fluid space of the membrane-less cell may be coupled to a common source of liquid, such as brine solution, or they may be coupled to different sources of liquid, such as pure water and brine solution, respectively, or to different brine solutions (or different concentrations of otherwise similar brine solutions). The modified anolyte solution may be coupled to an anolyte tank for use and/or storage. Also, the catholyte solution produced by the membrane-based cell may be coupled to a catholyte tank for use and/or storage, or may be disposed of as appropriate. In any event, because the anolyte solution from the first cell is mixed with the bleach solution from the second cell, the two cells may be seen as being in parallel, at least fluidically.
The present invention, in another aspect, provides a dual electrochemical cell device to produce modified anolyte solution. To that end, and in accordance with this aspect of the present invention, a plurality of anode and cathode pairs are separated by a partition and secured together as a single unit to define two segments of electrochemical cells in a unitary structure to either side of the partition. In one segment, each anode and cathode pair has a membrane between the anode and cathode thereof to define a membrane-based electrochemical cell, and in the other segment a fluid space between the anode and cathode of each anode and cathode pair is uninterrupted to define a membrane-less electrochemical cell. The partition is advantageously fluid impermeable such that in one unitary structure, there are two, effectively independent, electrochemical cells.
The membrane-based and membrane-less cells can be fluidically coupled in a number of ways, including in parallel fashion such that anolyte solution from the membrane-based cell is mixed with bleach solution from the membrane-less cell. Alternatively, the anolyte space of the membrane-based cell may be coupled to the fluid space of the membrane-less cell to couple the anolyte solution from the membrane-based cell into the fluid space of the membrane-less cell segment such that when the anode and cathode of the membrane-less cell segment are powered, anolyte solution therein is converted to modified anolyte solution. In that arrangement, the cell segments may be seen as being fluidically in series, rather than in parallel.
By virtue of the foregoing, there is thus provided, in one aspect, a system and method for producing a modified anolyte solution possessing desirable cleaning capabilities, but without the drawbacks of the anolyte solutions produced by typical electrochemical cells. There is further provided, in another aspect, a dual electrochemical cell device. These and other advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the present invention.

FIG. 1 is a diagrammatic depiction of a system of a fluidically parallel membrane-based electrochemical cell and a membrane-less electrochemical cell for producing modified anolyte solution in accordance with the principles of one aspect of the present invention;

FIG. 2 is a diagrammatic depiction of a system for producing modified anolyte solution including the system of fluidically parallel electrochemical cells of FIG. 1;

FIG. 3 is an exploded, schematic view of an alternative embodiment of a membrane-based electrochemical cell for use in place of the membrane-based electrochemical cell of the systems of FIGS. 1 and 2;

FIG. 4 is an exploded, schematic view of an alternative embodiment of a membrane-less electrochemical cell for use in place of the membrane-less electrochemical cell of the systems the systems of FIGS. 1 and 2;

FIG. 5A is an exploded, schematic view of a dual electrochemical cell device having a membrane-based electrochemical cell in one segment, a membrane-less electrochemical cell segment in another segment, and the segments separated from one another by a partition in accordance with another aspect of the present invention;

FIG. 5B is a diagrammatic depiction of the dual electrochemical cell device of FIG. 5A with the cell components of each of the segments and the partition secured together as a single unit or unitary structure;

FIG. 6 is a diagrammatic depiction of the dual electrochemical cell device of FIGS. 5A and 5B, with the segments fluidically coupled in parallel; and

FIG. 7 is a diagrammatic depiction of the dual electrochemical cell device of FIGS. 5A and 5B, with the segments fluidically coupled in series.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to FIG. 1, there is shown a system 10 for producing modified anolyte solution as at 12 in accordance with the principles of the present invention. System 10 includes a first electrochemical cell 14 and a second electrochemical cell 16 fluidically coupled in parallel as will be described herein. The first electrochemical cell 14 may be a conventional membrane-based electrochemical cell and includes a pair of foraminous electrodes 20, 22, the electrode 20 being an anode and the electrode 22 being a cathode. An ion exchange membrane 24 is situated between the anode 20 and the cathode 22 such that the first electrochemical cell 14 may be seen as being a membrane-based electrochemical cell. An anolyte space 30 is provided between the anode 20 and the membrane 24, and a catholyte space 32 is provided between the cathode 22 and the membrane 24.
A first liquid 34 may be introduced into the anolyte space 30 via a first input 35 coupled to the anolyte space 30. The first input 35 may be connected directly into the anolyte space 30 and/or indirectly through the anode 20, such as through apertures 20′ therein (FIG. 3). A second liquid 36 may be introduced into the catholyte space 32 via a second input 37 coupled to the catholyte space 32. The second input 37 may be connected directly into the catholyte space 32 and/or indirectly through the cathode 22, such as through apertures 22′ therein (FIG. 3). When the electrodes 20, 22 are powered such as by a power supply 38 (FIG. 2), a first anolyte solution 40 is produced in the anolyte space 30 from the first liquid 34 and is accessible at a first output 41 coupled to the anolyte space 30. Also, a catholyte solution 42 is produced in the catholyte space 32 from the second liquid 36 and is accessible at a second output 43 coupled to the catholyte space 32. The first output 41 may be connected directly into the anolyte space 30 and/or indirectly through the anode 20, such as through apertures 20′ therein. Similarly, the second output 43 may be connected directly into the catholyte space 32 and/or indirectly through the cathode 22, such as through apertures 22′ therein. As can be seen, inputs 35 and 37 are to one side of electrochemical cell 14 with outputs 41 and 43 being disposed to an opposite side thereof.
Where the membrane 24 is a cation exchange membrane, the first liquid 34 is advantageously a brine solution. The second liquid 36 may be either a brine solution or pure water. Where the membrane is an anion exchange membrane, the second liquid 36 is advantageously a brine solution, and the first liquid 34 may be either a brine solution or pure water.
The second electrochemical cell 16 may be a conventional non-membrane-based electrochemical cell and includes a pair of solid, i.e., non-foraminous, electrodes 50, 52, the solid electrode 50 being an anode and the solid electrode 52 being a cathode. A fluid space 54, such as a bleach space, between the solid electrodes 50, 52 is uninterrupted by a membrane, such that the second electrochemical cell 16 may be seen as being a membrane-less electrochemical cell. A third liquid 60, which is advantageously a brine solution, may be introduced into the bleach space 54 via a third input 61 coupled to the bleach space 54. When electrodes 50, 52 are powered such as by a power supply 38 (FIG. 2), a bleach solution 62, such as a sodium hypochlorite bleach, is produced in the bleach space 54 from the third liquid 60 and is accessible at a third output 63 coupled to the bleach space 54. The third input 61 may be connected directly into the bleach space 54. Similarly, the third output 63 may be connected directly into the bleach space 54. It will be appreciated that while anode 50 and cathode 52 are advantageously solid, if either or both of them were foraminous instead, then the third input 61 or the third output 63 may be connected indirectly into the bleach space 54 through the anode 50 or cathode 52 via apertures (not shown) therein. As can be seen, input 61 is to one side of electrochemical cell 16 with output 63 being disposed to an opposite side thereof.
In accordance with one aspect of the present invention, the cells 14 and 16 are fluidically in parallel. To that end, the anolyte space 30 and bleach space 54 are in fluid communication so as to mix the first anolyte solution 40 and the bleach solution 62 to produce the modified anolyte solution 12. The first and third outputs 41, 63 are coupled together so that the first anolyte solution 40 and the bleach solution 62 mix to produce the modified anolyte solution 12. The first and third outputs 41, 63 are also coupled to a further output 64 from which the modified anolyte solution 12 is accessible.
Inputs 35 and 37 may be coupled together such that the first and second liquids 34 and 36 introduced into the anolyte space 30 and the catholyte space 32 may be the same and from a common source. Or the inputs 35 and 37 may be independent such that first and second liquids 34 and 36 introduced into the anolyte space 30 and the catholyte space 32 may be from different sources and so can be different liquids. Similarly, inputs 35 and 61 may be coupled together such that the first and third liquids 34 and 60 introduced into the anolyte space 30 and the bleach space 54 may be the same and from a common source, particularly where both liquids are to be a brine solution. Alternatively, inputs 37 and 61 may be coupled together such that the second and third liquids 36 and 60 introduced into the catholyte space 32 and the bleach space 54 may be the same and from a common source, particularly where both liquids are to be a brine solution. Further alternatively, all three of inputs 35, 37, and 61, may be coupled together such that the first, second, and third liquids 34, 36, and 60 introduced into the anolyte space 30, the catholyte space 32, and the bleach space 54 may be the same and from a common source, particularly where all three liquids are to be a brine solution. Or all three of the inputs 35, 37, and 61, may be independent such that the first, second, and third liquids 34, 36, and 60 introduced into the anolyte space 30, the catholyte space 32, and the bleach space 54 may be from different sources and so can be different liquids. As a consequence, the brine solution used in cell 14 may be different, or of a different concentration, than the brine solution use in cell 16, by way of example.
A typical brine solution used for the third liquid 60 and/or for either or both of the first and second liquids 34 and 36, is a saline solution wherein the electrolyte is NaCl at a concentration of 0.5 to 2.5 g/l. However, other brine solutions of other salts and/or concentrations may be used. By way of example, the electrolyte could be KCl. In regard to the third liquid 60, irrespective of the electrolyte involved, the solution 62 produced by the cell 14 is considered a bleach solution.
Referring next to FIG. 2, a system 70 for producing modified anolyte solution 12 includes the fluidically parallel first and second electrochemical cells 14, 16 of system 10 with membrane 24 being a cation exchange membrane, as well as a liquid input assembly 72 for producing the first, second, and third liquids 34, 36, 60, and a product output assembly 74 for handling the first anolyte solution 40, the catholyte solution 42, the bleach solution 62, and the modified anolyte solution 12.
The liquid input assembly 72 includes a tap water conduit 78 connectable with a supply of water 80, such as a municipal water source. A tap water control valve 82 is coupled with the tap water conduit 78 and regulates the flow of tap water through the tap water conduit 78. The tap water control valve 82 can be actuated manually or electronically. The tap water conduit 78 is also coupled with a water filter 84, which may be any appropriate water filter the selection of which may depend on the qualities of the supply of water used. For example, the water filter 84 may include diatomaceous earth or carbon media, filter elements of various porosity sizes, such as 25-microns, 10-microns, and 5-microns, combinations of the same, or other appropriate filtering devices. A filtered water conduit 86 receives water that has been processed by the water filter 84 and is coupled with a water softener 88. The selection of the water softener 88 may also depend on the qualities of the supply of water used. For example, the water softener 88 can be a standard ion exchange water softener or a reverse osmosis unit. A water purification device (not shown) can also advantageously be included in the liquid input assembly 72.
Water that has passed through the water filter 84 and the water softener 88 is referred to herein as pure water and coupled through a pure water conduit 90 to be available as the second liquid 36 for the first electrochemical cell 14 via a second conduit 92 coupled to the input 37 and via a third conduit 94 to a brine tank 100 as will be described. Advantageously, the pure water could also be diverted and stored in a tank (not shown) for later use.
The liquid input assembly 72 further includes the brine tank 100 and a brine pump 102. Pure water is coupled with the brine tank 100 via the conduits 90, 94 to create a brine solution precursor. The brine solution precursor formed in the brine tank 100 is pumped at controlled levels by the brine pump 102 through a brine solution precursor conduit 104 and into a fourth conduit 105 which couples pure water from conduit 90 as to mix with the brine solution precursor to form a brine solution to be available as the first liquid 34 for the first electrochemical cell 14 via a fifth conduit 106 coupled to the inlet 35, and as the third liquid 60 via a sixth conduit 107 coupled to the fifth conduit 106 and the inlet 61. The brine pump 102 is advantageously controlled so that the brine solution achieves a target electrical conductivity.
To that end, a controller 108 receives a signal from a conductivity sensor 109 which measures the electrical conductivity of the brine solution in the fifth conduit 106. That signal is used by controller 108 to control the rate or speed of brine pump 102 whereby to adjust the amount of brine precursor solution to mix with the pure water. In one embodiment, the controller 108 generates a control signal to the pump 102 in the range of 4-20 mA.
Input conduit control valves 110 a, 110 b, 110 c are provided in the conduits 92, 106, and 107, respectively for controlling the flow of the respective liquids into the respective spaces of the electrochemical cells 14, 16. The input conduit control valves 110 a, 110 b, 110 c can be actuated manually or electronically.
Controller 108 also causes the power supply 38 to power the anodes and cathodes 20, 22 and 50, 52 of the cells 14, 16 to produce the first anolyte solution 40, the catholyte solution 42, the bleach solution 62.
The product output assembly 74 includes a catholyte conduit 112 and a catholyte tank 114. The catholyte conduit 112 is coupled with the second output 43 and the catholyte tank 114 to fluidically couple the catholyte space 32 and the tank 114 which receives the catholyte solution 42.
The product output assembly 74 also includes an anolyte conduit 116 and a bleach conduit 118 coupled with the first output 41 and the third output 63, respectively, and the further output 64 so as to mix the first anolyte solution 40 and the bleach solution 62 to form the modified anolyte solution 12 to be accessible at the further output 64. The product output assembly 74 also includes a modified anolyte conduit 120 and an anolyte tank 122. The modified anolyte conduit 120 is coupled with the further output 64 and the anolyte tank 122 to fluidically couple the modified anolyte solution 12 to be received in the anolyte tank 122.
The pH of the modified anolyte solution 12 is monitored with a pH sensor 124 coupled to the modified anolyte conduit 120. Signals from the pH sensor 124 are coupled to the controller 108 which generates control signals to the power supply 38 to cause the power supply 38 to power the anode 50 and cathode 52 at a constant current, which may be adjusted or set as desired. The first anolyte solution 40 may be at a pH of about 1-3. The desired pH of the modified anolyte solution 12 is about 4-5. Hence, the controller 108 causes the constant current output from the power supply 38 to adjust to a level sufficient to result in a pH for the bleach solution 60 which will cause the modified anolyte solution 12 to have a pH of approximately 4-5. While only one power supply 38 is shown for both electrochemical cells 14, 16, separate power supplies may be used. For example, power supply 38 may be used to power electrodes 50, 52 of the second electrochemical cell 16 and a separate power supply (not shown) may be used to power the electrodes 20, 22 of the first electrochemical cell 14. That separate power supply may also get control signals from controller 108, but the signals may be preset or user adjustable, rather than in response to any characteristic of the liquids involved in the system 70.
Further, while the catholyte solution 40 is shown as being received in a catholyte tank 114, it could alternatively be disposed of directly rather than via such a tank. In any event, the modified anolyte solution 12 and the catholyte solution 40 are available for immediate use from the tanks 122, 114 respectively, or for later use with the tanks 122, 114 serving as storage vessels for the respective solutions.
In use, the liquids 34, 36, and 60 are coupled with the first electrochemical cell 14 and the second electrochemical cell 16, and the respective anodes 20, 50 and cathodes 22, 52 of the electrochemical cells 14, 16 are powered to create the first anolyte solution 40, the catholyte solution 42, and the bleach solution 62. In particular, a brine solution is introduced into the anolyte space 30 in the first electrochemical cell 14 and the bleach space 54 in the second electrochemical cell 16. Additionally, pure water is introduced into the catholyte space 32 in the first electrochemical cell 14. When the anode 20 and cathode 22 in the first electrochemical cell 14 are powered, first anolyte solution 40 and catholyte solution 42 are produced in the anolyte and catholyte spaces 30, 32, respectively. Similarly, when the anode 50 and cathode 52 in the second electrochemical cell 16 are powered, bleach solution 62 is produced in the bleach space 54. The first anolyte solution 40 and bleach solution 62 are mixed to form the modified anolyte solution 12. The modified anolyte solution 12 can be coupled with, or directed to, the anolyte tank 122, and the catholyte solution 42 can be coupled with, or directed to, the catholyte tank 114. The modified anolyte solution, and the catholyte solution if desired, may be used for cleaning purposes such as for laundry, surface cleaning, or within piping such as for clean-in-place applications.
In particular, the first anolyte solution 40 produced in the first electrochemical cell 14 will have a pH in the range of about 1-3, and the catholyte solution 42 produced in the first electrochemical cell 14 will have a pH in the range of about 11.5-12. The bleach solution 62 produced in the second electrochemical cell 16 will have a pH in the range of about 8.5-9.5, and the modified anolyte solution 12 will have a pH of about 4-5. Thus, mixing the first anolyte solution 40 with the bleach solution 62 provides a modified anolyte solution 12 having a higher pH than the first anolyte solution 40 alone. Without being limited to any particular theory or mechanism, it is believed that a pH of about 4-5 increases the solubility of active chlorine in the modified anolyte solution 12 and decreases the corrosion potential associated with lower pH values. Thereby, the modified anolyte solution 12 has a less extreme pH value than the first anolyte solution 40 and while it provides the desired cleaning properties, it overcomes the drawbacks that would have been expected from the first anolyte solution 40.
In the systems 10 and 70 described herein, the first electrochemical cell 14 includes only one pair of electrodes 20, 22 and one membrane 24. Alternatively, multiple pairs of electrodes 20, 22 each with a respective membrane 24 therebetween could be employed. To that end, and with reference to FIG. 3, an alternative embodiment of a conventional membrane-based first electrochemical cell 14′ is shown in an exploded, schematic view with like parts between cells 14 and 14′ bearing the same reference numbers.
FIG. 3 shows that the first electrochemical cell 14′ includes a plurality of anolyte spaces 30 and catholyte spaces 32. As shown, the plurality of anodes 20 and cathodes 22 are arranged so as to provide adjacent anolyte spaces 30 and catholyte spaces 32. Adjacent respective anolyte spaces 30 and catholyte spaces 32 are separated by a spacer 130. The anodes 20 and cathodes 22 in adjacent anolyte and catholyte spaces 30, 32 are arranged in an opposite manner so that the same types of electrodes (either anodes or cathodes) border the spacers 130 between the spaces 30, 32. For example, a set of components in the first electrochemical cell 14′ may be arranged in the following order: anode-membrane-cathode-spacer-cathode-membrane-anode-spacer. This pattern is repeated for the number of anolyte and catholyte spaces 30, 32 in the cell.
All the anodes 20 in the first electrochemical cell 14′ are electrically coupled to one another and to the power supply 38. Similarly, all the cathodes 22 in the first electrochemical cell 14′ are electrically coupled to one another and to the power supply 38.
A gasket 132 separates adjacent components in the first electrochemical cell 14′. Thus, a gasket 132 is positioned between each anode 20 and membrane 24, between each cathode 22 and membrane 24, and between each cathode 22 or anode 20 and each spacer 130. In addition, spacers 130 and associated end plates 133 are included at each end to close off the last of the plurality of anodes 20 and anolyte spaces 30, and the last of the plurality of cathodes 22 and catholyte spaces 32.
The anodes 20, cathodes 22, and membranes 24 in the first electrochemical cell 14′ are generally planar, and can have any suitable composition. The gaskets 132, spacers 130, and end plates 133 are also planar such that when compressed together from end to end, they can be secured such as by bolts (not shown) drawing the end plates 133 together with the components therebetween brought together into a fluid tight (except for the inlets and outlets) assembly. Advantageously, the anodes 20 are foraminous (thus having apertures 20′therethrough) and are made of pure titanium coated with RuO₂and IrO₂, and the cathodes 22 are foraminous (thus having apertures 22′ therethrough) and are made of uncoated pure titanium, although in other embodiments, they could be solid. Also advantageously, the RuO₂and IrO₂of the anode coating are preferably present in equal amounts, but the ratio may also vary from about 60/40 to about 40/60. The membranes 24 in the first electrochemical cell 14′ are advantageously cation exchange membranes, but could be anion exchange membranes.
As shown, each input 35 is associated with a respective spacer 130 adjacent an anolyte space 30 (or between adjacent anolyte spaces 30) so as to fluidically couple the first liquid 34 into the respective anolyte spaces 30 through the apertures 20′ in the anodes 20. The inputs 35 are also fluidically coupled to the conduit 106 so the same liquid (brine solution) can be coupled to each anolyte space 30. Likewise, each input 37 is associated with a respective spacer 130 adjacent a catholyte space 32 (or between adjacent catholyte spaces 32) so as to fluidically couple the second liquid 36 into the respective catholyte spaces 32 through the apertures 22′ in the cathodes 22.
The inputs 37 are also fluidically coupled to the conduit 92 so that the same liquid (pure water) can be coupled to each catholyte space 32. In a similar manner, each output 41 is associated with a respective spacer 130 adjacent an anolyte space 30 (or between adjacent anolyte spaces 30) so as to fluidically couple the first anolyte solution 40 out of the respective anolyte spaces 30 through the apertures 20′ in the anodes 20. The outputs 41 of the anolyte spaces 30 are fluidically coupled to the anolyte conduit 116 to combine the first anolyte solution 40 from all of the spaces 30 to be mixed with the bleach solution 62. Similarly, each output 43 is associated with a respective spacer 130 adjacent a catholyte space 32 (or between adjacent catholyte spaces 32) so as to fluidically couple the catholyte solution 42 out of the respective catholyte spaces 32 through the apertures 22′ in the cathodes 22. The outputs 43 of the catholyte spaces 32 are fluidically coupled to the catholyte conduit 112 to combine the catholyte solution 42 for receipt by the catholyte tank 114.
Given the generally planar construction of the anodes 20, cathodes 22, and membranes 24, the anolyte and catholyte spaces 30, 32 have a major lengthwise dimension, and the inputs 35, 37 and outputs 41, 43 are arranged on opposite sides of that lengthwise dimension. Thus, each anolyte space 30 and each catholyte space 32 extends lengthwise between an area generally adjacent a respective input 35, 37 to an area generally adjacent a respective output 41, 43.
Referring next to FIG. 4, an alternative embodiment of a conventional non-membrane-based second electrochemical cell 16′ is shown in an exploded, schematic view with like parts between cells 16 and 16′ bearing the same reference numbers. In second electrochemical cell 16′ a spacer 134 is included between the anode 50 and the cathode 52, and gaskets 136 are positioned between the anode 50 and the spacer 134, the cathode 52 and the spacer 134, and between the anode 50 and cathode 52 and respective end plates 137. The third inlet 61 and third output 63 are associated with opposite ends of the spacer 134 to couple the third liquid 60 into, and the bleach solution 62 out of, the bleach space 54 defined within spacer 134 between anode 50 and cathode 52. Further, the anode 50 and cathode 52 of the second electrochemical cell 16′ may advantageously be solid metal plates of pure titanium (the anode may also be coated with RuO₂and IrO₂like the anodes 20 of the first electrochemical cells 14, 14′). Like cell 14′, the components of cell 16′ are advantageously planar and may be compressed and secured together into a fluid tight (except for the inlet 61 and outlet 63) assembly.
In use, the first and second electrochemical cells 14′, 16′ each function in a similar manner as the first and second electrochemical cells 14, 16 described above.
In accordance with a second aspect of the present invention, and as shown in FIGS. 5A, 5B, 6, and 7, a dual electrochemical cell device 200 is provided for producing modified anolyte solution by, in effect, compressing the respective anodes, cathodes, spacers, gaskets, and end plates of the cells 14′ and 16′ together end to end into a fluid tight (except for the inlets and outlets) assembly. To that end, a plurality of anode and cathode pairs 202 are separated by a partition 204 (instead of end walls 133 and 137, which are at respective ends of the device 200 as seen particularly in FIG. 5B) and secured together as a single unitary structure 206. The partition 204 divides the dual cell device 200 into two segments of electrochemical cells, with one electrochemical cell on each side of the partition 204. In particular, a first electrochemical cell 210 is included in a first segment 212, and a second electrochemical cell 214 is included in a second segment 216. The partition is advantageously fluid impermeable such that in the one unitary structure 206, there are two, effectively independent, electrochemical cells 210, 214. The first cell 210 is a membrane-based electrochemical cell and produces a first anolyte solution 218. The first cell 210 may also produce a catholyte solution 220. The first cell 210 is of similar construction and operates in a similar manner as the first electrochemical cells 14 and 14′ described above. The second cell 214 is a membrane-less electrochemical cell, and according to one aspect of the present invention, produces a liquid solution 222. The second cell 214 is of similar construction to that of the second electrochemical cells 16 and 16′ described above.
In particular, one or more anode and cathode pairs 202 in the first cell 210 each include a membrane 230 between the respective anode 232 and cathode 234 thereof. An anolyte space 236 is provided between each anode 232 and each membrane 230, and a catholyte space 238 is provided between each cathode 234 and each membrane 230. The first cell 210 includes inputs and outputs like those described above for cell 14′. The anode 232 and cathode 234 are advantageously foraminous, and the membrane 230 is an ion exchange membrane which is advantageously a cation exchange membrane.
In the second cell 214, a fluid space 244 between an anode 240 and a cathode 242 of that pair 202 is uninterrupted by a membrane. The anode 240 and cathode 242 are advantageously solid. The second cell 214 includes inputs and outputs like those described above for cell 16′. FIG. 5A shows the various components of device 200 in an exploded view, with the components being compressed together into a unitary, fluid tight (except for the inlets and outlets) assembly being shown schematically in FIG. 5B. In that regard, bolts 205, which may be insulated to pass through exposed aspects of the anode and cathode pairs 202, pull ends 133, 137 tightly together with the intervening, generally planar components sandwich therebetween into a generally fluid tight (except for the inlets and outlets thereof) assembly 200.
The first and second cells 210, 214 can be fluidically coupled in a number of ways. As shown in FIG. 6, the first and second cells 210, 214 are fluidically coupled in parallel. To that end, brine solution coupled to the anolyte spaces 236 of the first cell 210 produces therefrom first anolyte solution 218, and brine solution coupled to the fluid space 244 of the second cell 214 produces therefrom a bleach solution 222. The first anolyte solution 218 from the first cell 210 is mixed with the bleach solution 222 from the second cell 214 to form a modified anolyte solution 250.
Alternatively, and as shown in FIG. 7, the first and second cells 210, 214 can be fluidically coupled in series. To that end, brine solution coupled to the anolyte spaces 236 of the first cell 210 produces therefrom first anolyte solution 218 which is introduced into the fluid space 244 of the second cell 214 to produce therefrom a modified anolyte solution 252 when the anode 240 and cathode 242 are powered.
By virtue of the foregoing, there is provided a system and method for producing a modified anolyte solution possessing desirable cleaning capabilities, but without the drawbacks of the anolyte solutions produced by typical electrochemical cells. There is further provided, in another aspect, a dual electrochemical cell device.
While the present invention has been illustrated by a description of particular embodiments thereof and specific examples, and while the embodiments have been described in some detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, the membrane-based cells 14, 14′ and 210 include a single membrane between the anode(s) and the cathode(s) thereof, the principles described herein are equally applicable to other configurations. By way of example, a second membrane could be included between the first membrane and the cathode, with the catholyte space being defined between the second membrane and the cathode. It will be seen, however, that the catholyte space is still necessarily between the first membrane and the cathode as well. Additionally, the space between the two membranes could contain a brine solution with other liquids in the anolyte and catholyte spaces, such as pure water and/or other brine solutions. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.

Claims

Having described the invention, what is claimed is:

1. A system for producing modified anolyte solution comprising:

a first electrochemical cell having a first anode, a first cathode, and an ionic exchange membrane therebetween, and having an anolyte space between the membrane and the first anode and a catholyte space between the membrane and the first cathode, whereby a first anolyte solution is produced from liquid in the anolyte space with the first anode and first cathode being powered; and

a second electrochemical cell having a second anode and a second cathode and having a bleach space between the second anode and the second cathode uninterrupted by a membrane, whereby a bleach solution is produced from a brine solution in the bleach space with the second anode and second cathode being powered;

the anolyte space and the bleach space being in fluid communication so as to mix the first anolyte solution and the bleach solution, whereby to produce a modified anolyte solution as a mixture of the first anolyte solution and the bleach solution.

2. The system of claim 1 further comprising respective outputs coupled to the anolyte space and the bleach space, the respective outputs being coupled so as to provide at a further output the modified anolyte solution.

3. The system of claim 1 further comprising an anolyte tank for receiving the modified anolyte solution.

4. The system of claim 1, whereby a catholyte solution is produced from liquid in the catholyte space with the first anode and first cathode being powered, the system further comprising a catholyte tank for receiving the catholyte solution.

5. The system of claim 4 further comprising an output coupled to the catholyte space, the output being fluidically coupled to the catholyte tank.

6. The system of claim 1, the membrane being a cation exchange membrane.

7. The system of claim 1, the membrane being an anion exchange membrane.

8. The system of claim 1, the first anode and the first cathode being foraminous, and the second anode and the second cathode being solid.

9. The system of claim 1, the first electrochemical cell comprising a plurality of first anodes, a plurality of first cathodes, and a plurality of respective ion exchange membranes therebetween to define a plurality of anolyte spaces between the respective membranes and first anodes and a plurality of catholyte spaces between the respective membranes and first cathodes, whereby a first anolyte solution is produced from liquid in the anolyte spaces with the first anodes and first cathodes being powered.

10. The system of claim 9, the plurality of anolyte spaces and plurality of catholyte spaces being arranged to provide adjacent anolyte spaces and adjacent catholyte spaces.

11. The system of claim 10 further comprising spacers between the anolyte spaces of adjacent anolyte spaces and between the catholyte spaces of adjacent catholyte spaces.

12. The system of claim 1, the first cathode and first anode being generally planar.

13. The system of claim 1, the membrane being generally planar.

14. The system of claim 1, the second cathode and second anode being generally planar.

15. A method of producing modified anolyte solution comprising:

producing a first anolyte solution in an anolyte space between a first anode and an ionic exchange membrane of a first electrochemical cell having the first anode, a first cathode, and the membrane therebetween;

producing a bleach solution in a bleach space between a second anode and a second cathode of a second electrochemical cell having the second anode and the second cathode uninterrupted by a membrane therebetween; and

combining the first anolyte solution and the bleach solution to form a modified anolyte solution.

16. The method of claim 15, producing the first anolyte solution including coupling brine solution to the anolyte space and powering the first anode and cathode.

17. The method of claim 16 further comprising coupling liquid to a catholyte space between the membrane and the cathode of the first electrochemical cell.

18. The method of claim 17 further comprising producing a catholyte solution in the catholyte space.

19. The method of claim 15, producing the bleach solution including coupling brine solution to the bleach space and powering the second anode and cathode.

20. The method of claim 15 wherein the first anode and the first cathode are foraminous and the second anode and the second cathode are solid.

21. A dual electrochemical cell device comprising:

a plurality of anode and cathode pairs

a partition between two of the pairs to define first and second segments, a first of the anode and cathode pairs being in the first segment, a second of the anode and cathode pairs being in the second segment; and

an ion exchange membrane disposed between the anode and cathode of the first pair, a fluid space between the anode and cathode of the second pair being uninterrupted by a membrane, the anode and cathode pairs and the partition being secured together as a single, unitary, generally fluid tight assembly.

22. The device of claim 21, the partition being fluid impermeable.

23. The device of claim 21, the anode and cathode of the first pair being foraminous, and the anode and cathode of the second pair being solid.

24. The device of claim 21, the membrane being a cation exchange membrane.

25. The device of claim 21, the membrane being an anion exchange membrane.

26. The device of claim 21 further comprising a first input and a first output coupled to a catholyte space between the membrane and cathode of the first pair, a second input and a second output coupled to an anolyte space between the membrane and the anodes of the first pair, and a third input and a third output coupled to the fluid space between the anode and the cathode of the second pair.

27. The device of claim 26, second and third outputs being fluidically coupled whereby to combine fluids from the anolyte and fluid spaces.

28. The device of claim 26, the second output being coupled to the third input.

29. The device of claim 26, the anodes and cathodes being generally planar.