U.S. patent application number 14/529233 was filed with the patent office on 2015-02-26 for electrolytic cell with catholyte recycle.
The applicant listed for this patent is Ecolab USA Inc.. Invention is credited to Scott R. Limback, Lylien Tan, Barry R. Taylor, Marvin C. Trulsen, Kevin A. Wuebben.
Application Number | 20150053569 14/529233 |
Document ID | / |
Family ID | 49913033 |
Filed Date | 2015-02-26 |
United States Patent
Application |
20150053569 |
Kind Code |
A1 |
Limback; Scott R. ; et
al. |
February 26, 2015 |
ELECTROLYTIC CELL WITH CATHOLYTE RECYCLE
Abstract
An improved electrolytic cell, its method and system is
disclosed. The electrolytic cell (12) is configured, at least in
one design, to recycle the catholyte to increase chlorine capture
and concentration in the output solution. The cell (12) includes at
least an anode chamber (39) and a cathode chamber (35). And in one
design, a chamber or reservoir (31) for that serves as a source of
anions and cations for the anode and cathode chambers. The outlet
(38) of the cathode chamber is preferably connected in fluid
communication with the inlet (44) of a degassing chamber (14) and
the outlet (46) of the degassing chamber is preferably connected in
fluid communication with the inlet (40) of the anode chamber.
Inventors: |
Limback; Scott R.; (St.
Paul, MN) ; Taylor; Barry R.; (Adrian, MI) ;
Wuebben; Kevin A.; (Apple Valley, MN) ; Trulsen;
Marvin C.; (Woodbury, MN) ; Tan; Lylien;
(Maplewood, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ecolab USA Inc. |
St. Paul |
MN |
US |
|
|
Family ID: |
49913033 |
Appl. No.: |
14/529233 |
Filed: |
October 31, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13546239 |
Jul 11, 2012 |
|
|
|
14529233 |
|
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|
Current U.S.
Class: |
205/349 ;
204/237; 204/278 |
Current CPC
Class: |
C25B 15/08 20130101;
C25B 1/26 20130101; C25B 9/00 20130101; C25B 9/08 20130101 |
Class at
Publication: |
205/349 ;
204/237; 204/278 |
International
Class: |
C25B 1/26 20060101
C25B001/26; C25B 9/00 20060101 C25B009/00; C25B 15/08 20060101
C25B015/08 |
Claims
1. An electrolytic cell configured to increase chlorine capture and
concentration in the cell's output solution, comprising: an anode
chamber and a cathode chamber with inlets and outlets; an
electrolyte feed adapted for providing electrolyte to an
intermediate chamber, the intermediate chamber being between the
anode chamber and the cathode chamber and having an intermediate
chamber inlet and an intermediate chamber outlet which are separate
from the anode chamber inlet and outlet and the cathode chamber
inlet and outlet, the electrolyte providing a source of anions and
cations to the anode and cathode chambers; a degassing chamber
having an inlet and outlet, the inlet connected in fluid
communication with the cathode chamber and the outlet connected in
fluid communication with the anode chamber and wherein the inlet of
the degassing chamber is elevated above the outlet of the anode
chamber to move catholyte through the anode chamber by gravity; the
outlet of the cathode chamber connected in fluid communication with
the inlet of the anode chamber; wherein the degassing chamber
includes a reservoir between the inlet and the outlet for
maintaining a liquid level; and the inlet of the cathode chamber
connected in fluid communication with a liquid source.
2. The electrolytic cell of claim 1 wherein the inlet from the
cathode chamber communicates catholyte from the cathode chamber
through the degassing chamber before recycling through the anode
chamber.
3. The electrolytic cell of claim 2 wherein the inlet of the
degassing chamber is elevated above the outlet of the degassing
chamber.
4. (canceled)
5. The electrolytic cell of claim 2 wherein the degassing chamber
includes an outlet vent elevated above the outlet of the anode
chamber.
6. The electrolytic cell of claim 2 wherein the reservoir has a
liquid level maintained generally at the level of the outlet of the
anode chamber.
7. The electrolytic cell of claim 2 further comprising a manifold
that incorporates the degassing chamber.
8. The electrolytic cell of claim 7 wherein the manifold includes:
a. a liquid inlet connected in fluid communication with the liquid
source and the inlet of the cathode chamber; and b. a solution
outlet connected in fluid communication with the outlet of the
anode chamber.
9. The electrolytic cell of claim 7 wherein the manifold further
comprises: a. a vent outlet connected in communication with the
degassing chamber; b. an anolyte drain outlet connected in fluid
communication with the anode chamber and the degassing chamber; and
c. a catholyte drain outlet connected in fluid communication with
the cathode chamber.
10. The electrolytic cell of claim 1 further comprising a chamber
connected in fluid communication with the electrolyte feed.
11. A method for chlorine capture in an electrolytic cell,
comprising: providing an electrolytic cell having an anode chamber
and a cathode chamber with inlets and outlets; feeding an
electrolyte to the cell for providing a source of anions and
cations to the anode and cathode chambers; recycling catholyte from
the cathode chamber through the anode chamber; providing a
degassing chamber, wherein the degassing chamber includes a
reservoir between the inlet and the outlet for maintaining a liquid
level; and dispensing an output solution from the anode
chamber.
12. The method of claim 11 further comprising communicating
catholyte from the cathode chamber through a degassing chamber
before recycling through the anode chamber.
13. The method of claim 12 venting gas from the catholyte in the
degassing chamber.
14. The method of claim 12 further comprising gravity feeding
catholyte from the degassing chamber through the anode chamber.
15. The method of claim 12 wherein the electrolytic cell includes a
manifold that incorporates the degassing chamber.
16. The method of claim 15 further comprising communicating liquid
in and out of each chamber through the manifold.
17. The method of claim 11 further comprising communicating
electrolytes from the electrolyte feed through the cell.
18. A system for increasing chlorine capture and concentration from
an electrolytic cell, comprising: an electrolytic cell having an
anode chamber and a cathode chamber having inlets and outlets; a
liquid source connected in fluid communication with the inlet of
the cathode chamber; and an electrolyte feed source adapted for
providing a source of anions and cations to the anode and cathode
chambers; and a degassing chamber having an inlet connected in
fluid communication with the outlet of the cathode chamber and an
outlet connected in fluid communication with the inlet of the anode
chamber, wherein the inlet of the degassing chamber is elevated
above the outlet of the anode chamber to move a catholyte through
the anode chamber by gravity, and wherein the degassing chamber
includes a reservoir between the inlet and the outlet for
maintaining a liquid level.
19. The system of claim 18 wherein the the reservoir has a liquid
level maintained generally at the level of the outlet of the anode
chamber.
20. The system of claim 18 wherein the inlet from the cathode
chamber communicates catholyte from the cathode chamber through the
degassing chamber before recycling through the anode chamber.
21. The system of claim 18 further comprising a manifold housing
the degassing chamber.
22. The system of claim 21 wherein the manifold includes one or
more of: a. a liquid inlet connected in fluid communication with
the liquid source and the inlet of the cathode chamber; b. a
solution outlet connected in fluid communication with the outlet of
the anode chamber; c. a vent outlet connected in communication with
the degassing chamber; d. an anolyte drain outlet connected in
fluid communication with the anode chamber and the degassing
chamber; e. a catholyte drain outlet connected in fluid
communication with the cathode chamber.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation Application of U.S. Ser. No.
13/546,239 filed Jul. 11, 2012, herein incorporated by reference in
its entirety.
FIELD OF THE INVENTION
[0002] The invention relates to an electrolytic cell, method and
system with a catholyte recycle feature. In particular, the
invention relates to an electrolytic cell configured to recycle
catholyte by gravity feed for increasing chlorine capture and
concentration from the in situ generation of electrolysis
solutions.
BACKGROUND OF THE INVENTION
[0003] The production of acidic electrolyzed water and alkaline
electrolyzed water by the electrolysis of water in which chlorine
electrolyte has been added is well-known. Commercially available
three-chamber electrolytic cells are one exemplary means for
electrolyzing sodium chloride solutions. In a conventional mode of
operation, these cells have two output solutions that are
simultaneously provided, namely an acidic solution containing
hypochlorous acid and hydrochloric acid in a relatively dilute form
(anolyte), and an alkaline solution containing sodium hydroxide
(catholyte). The hypochlorous acid in the acidic solution is a form
of free chlorine and a very effective germicide. However, in the
acidic solution, hypochlorous acid is relatively unstable; it is in
equilibrium with the molecular chlorine in the solution, which over
time will come out of the solution. Some of the chlorine in the
solution escapes into the vapor head space above a contained body
of the solution. There is also a chlorine odor associated with the
solution, as well as the possibility of chlorine concentrations
developing in the vapor space above the body of chlorine solution
that exceed allowable NIOSH limits. As the need arises to generate
a solution with greater germicidal efficacy (e.g., to create a
solution that can be registered with the EPA as a sanitizer or
disinfectant), the concentrations of chlorine in the vapor space
above the solution become more problematic.
[0004] In addition, the chlorine in hypochlorous acid is a very
aggressive oxidizing agent. Surfactants that might be added to the
solution to enhance wetting properties are readily attacked by the
chlorine in the hypochlorous acid. The same is true for surface
materials with which the solution might come into contact during
its application. Both of these problems become more significant as
the strength of the solution is increased to enhance efficacy. All
of these problems are mitigated by adding a base, such as a sodium
hydroxide, to the acidic solution to raise its pH and to create an
alkaline solution in which the chlorine in the hypochlorous acid
has been converted to its ionic form, the hypochlorite ion.
[0005] In traditional cells, sodium hydroxide is produced during
the operation of the cell. Therefore, a use in this art has been
identified which includes using the alkaline solution in a
self-contained process to neutralize the acidic solution produced
by the cell and generate an alkaline sodium hypochlorite solution.
This can be accomplished by simply mixing the acidic and alkaline
solutions together in a post-cell operation. However, this approach
has disadvantages. For instance, the free chlorine concentration in
the acidic solution is diluted by simply mixing the two streams
together. In addition, combining the two streams in a post-cell
mixing operation does not allow for possible increases in chlorine
capture efficiency.
[0006] Accordingly, it is an objective of the claimed invention to
develop an improved electrolytic cell, method and system for
generating in situ electrolysis solutions such as chlorine bleach
solutions from salt and water.
[0007] A particular object for the invention is an improved
electrolytic cell that provides for increased chlorine capture
efficiency and concentrations by recycling catholyte through the
anode chamber of the electrolytic cell.
[0008] A further object of the invention is to accomplish catholyte
recycling by gravity feed.
[0009] These and other objects of the invention will be readily
ascertained by one skilled in the art based on the description of
the invention.
BRIEF SUMMARY OF THE INVENTION
[0010] In one embodiment, the invention is an electrolytic cell
configured to increase chlorine capture and concentration in the
cell's output solution. The electrolytic cell includes an anode
chamber and a cathode chamber with inlets and outlets, and an
electrolyte feed that provides a source of anions and cations to
the anode and cathode chambers. The outlet of the cathode chamber
is connected in fluid communication with the inlet of the anode
chamber and the inlet of the cathode chamber is connected in fluid
communication with a liquid source. In a preferred form, the cell
includes a degassing chamber having an inlet and outlet. The inlet
of the gassing chamber is connected in fluid communication with the
cathode chamber and the outlet of the degassing chamber is
connected in fluid communication with the anode chamber to
accomplish recycling of the catholyte through the anode chamber.
The inlet of the degassing chamber is also elevated above the
outlet of the anode chamber to move catholyte through the anode
chamber by gravity.
[0011] In another embodiment, the invention is a method for
chlorine capture in an electrolytic cell. An electrolytic cell
having an anode chamber and a cathode chamber with inlets and
outlets is provided. An electrolyte is fed to the cell for
providing a source of anions and cations to the anode and cathode
chambers. Catholyte is recycled from the cathode chamber through
the anode chamber and an output solution is dispensed from the
anode chamber. In a preferred form of the invention, the method
also includes communicating catholyte from the cathode chamber
through a degassing chamber before recycling through the anode
chamber, and gravity feeding catholyte from the degassing chamber
through the anode chamber.
[0012] In another embodiment, the invention is a system for
increasing chlorine capture and concentration from an electrolytic
cell. The system includes an electrolytic cell having an anode
chamber and a cathode chamber having inlets and outlets. A liquid
source is connected in fluid communication with the inlet of the
cathode chamber and an electrolyte feed source provides a source of
anions and cations to the anode and cathode chambers. A degassing
chamber has an inlet connected in fluid communication with the
outlet of the cathode chamber and an outlet connected in fluid
communication with the inlet of the anode chamber. In a preferred
form, the degassing chamber includes a reservoir between the inlet
and the outlet. The reservoir has a liquid level maintained
generally at the level of the outlet of the anode chamber to move
catholyte through the anode chamber by gravity. The system also
includes a manifold housing the degassing chamber.
[0013] While multiple embodiments are disclosed, still the other
embodiments of the present invention will become apparent to those
skilled in the art from the following detailed description, which
shows and describes illustrative embodiments of the invention.
Accordingly, the drawings and detailed description are to be
treated as illustrative in nature and not restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is an exemplary illustration of a system of the
present invention using an electrolytic cell.
[0015] FIG. 2 is another exemplary illustration of a system of the
present invention using the electrolytic cell shown in FIG. 1.
[0016] FIG. 3 is an exemplary schematic illustrating one embodiment
of an electrolytic cell of the present invention.
[0017] FIG. 4 is an exemplary schematic illustrating another
embodiment of an electrolytic cell of the present invention.
[0018] FIG. 5 is a plot illustrating the change in pH of the output
solution versus the input current for both 100% catholyte recycle
and no recycle tests.
[0019] FIG. 6 is a plot illustrating the increase in chlorine
capture rate versus the change in input current for both 100%
catholyte recycle and no recycle tests.
[0020] FIG. 7 is a plot illustrating the change in chlorine capture
versus the input current for both 100% catholyte recycle and no
recycle tests.
[0021] FIG. 8 is a plot illustrating the current efficiency versus
the input current for both 100% catholyte recycle and no recycle
tests.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] The present invention relates to an improved electrolytic
cell, its method, and a system disclosing the same. Various
embodiments of the present invention will be described in detail
with reference to the drawings, wherein like reference numerals
represent like parts throughout the several views. Reference to
various embodiments does not limit the scope of the invention.
Figures represented herein are not limitations of the various
embodiments according to the inventions and are presented for
exemplary illustration of the invention only.
[0023] FIG. 1 illustrates an exemplary system 10 of the present
invention for accomplishing in situ generation of electrolysis
solutions using an electrolytic cell, such as an electrolytic cell
12 with two or more chambers. The system 10 illustrated in FIG. 1
is one exemplary embodiment of a system configured to increase the
chlorine capture efficiency and concentration in an output solution
provided by the cell 12. In the exemplary system 10 illustrated in
FIG. 1 is shown several components for facilitating operation of
the cell 12. The cell 12 is divided by membranes into an
electrolysis chamber with a positively charged electrode (anode), a
middle or intermediate chamber, and an electrolysis chamber with a
negative charge electrode (cathode). Further description of the
electrolytic cells suitable for use according to the invention is
set forth in U.S. patent application Ser. No. 12/743,785 (Ecolab
USA Inc.), which is herein incorporated by reference in its
entirety.
[0024] One of the inputs to the cell 12 is water from a water
source. Water is communicated through a line which is selectively
opened and closed by a valve 26. A pressure regulator 24 may be
incorporated into the line to regulate the pressure of the water
from the source pressure as is appropriate for use in the system
10. A pump 22, such as a peristaltic pump, may also be included in
the line to pump water from the water source into the cathode
chamber 35 through the cathode chamber inlet 36. The pump 22 allows
the volume of water communicated through the inlet 36 to be
controlled, such as at a preferred volumetric rate of flow. The
water passes through the cathode chamber 35, producing an alkaline
solution containing sodium hydroxide (catholyte). Catholyte exits
the cathode chamber 35 through cathode chamber outlet 38. The
catholyte is then communicated to the degassing tower 14 as new
water is pumped into the cathode chamber 35 from pump 22. The
catholyte enters the degassing tower 14 through the degassing tower
inlet 44. The degassing tower 14 separates hydrogen gas from the
catholyte liquid solution received from the cathode chamber 35 of
the electrolytic cell 12. The hydrogen gas exits the degassing
tower 14 through a vent 48 which allows the hydrogen gas to be
released into the atmosphere at atmospheric pressure. In one
design, gas (e.g., hydrogen gas) bubbles are separated from the
catholyte at the point where the catholyte liquid enters the
degassing tower inlet 44 with the gas being vented and the degassed
fluid falling by gravity to the accumulation chamber at the bottom
of the degassing tower 14. The degassing tower 14 includes an
overflow 50 to allow excess catholyte solution to be drained off
into a drain or into a container (e.g., a day tank) for storing the
catholyte solution. The degassing tower 14 also includes a
degassing tower outlet 46 connected in fluid communication with
pump 16 (e.g., a peristaltic pump). The pump 16 pumps the catholyte
solution from the degassing tower 14 into the anode chamber 39 of
the electrolytic cell 12 via the anode chamber inlet 40. Use of the
pump 16 permits the feed rate of catholyte solution into the anode
chamber 39 to be controlled, (e.g., at a rate slightly less than
the rate at which catholyte is discharged from the cathode chamber
35) to avoid pumping air into the anode chamber 39. The catholyte
enters the anode chamber 39, creating an alkaline solution in which
the chlorine and the hypochlorous acid has been converted to its
ionic form, the hypochloric ion, thereby generating alkaline sodium
hypochlorite solution. The output solution is communicated from the
anode chamber by dispensing via anode chamber outlet 42. To
facilitate the electrolytic process, electrolyte such as a brine
solution is formulated in tank 18. The electrolyte is pumped from
the tank 18 through outlet 58 using pump 20. The electrolyte is
communicated through a line into an intermediate chamber in the
electrolytic cell 12 via inlet 32. The electrolyte passes through
the intermediate chamber between the cathode chamber 35 and the
anode chamber 39 and exits the electrolytic cell 12 through outlet
34. The electrolyte then returns back to the tank 18 by traveling
through the line and through tank inlet 52. The tank 18 is fed
water from a water source. A valve 28 may be connected inline for
selectively opening and closing the line to permit flow of water
into the tank 18 through inlet 54. A flow control device 30 may be
included in-line to control the rate of which water is introduced
into the tank 18. One or more sensors, such as a level sensor 56,
may be used in connection with tank 18 to monitor the volume of
electrolyte within the tank.
[0025] As illustrated in FIG. 1, incorporating a pump 16 between
the outlet 38 of the cathode chamber 35 and the inlet 40 of the
anode chamber 39 allows the rate at which catholyte from the
cathode chamber 35 is introduced into the anode chamber 39 to be
controlled. FIG. 2 illustrates another exemplary system 10 of the
present invention, such as where it is desirable to recirculate all
of the catholyte (i.e., "100% recycle") produced by the cathode
chamber 35 through the anode chamber 39 of the electrolytic cell
12.
[0026] In FIG. 2, another exemplary system 10 of the present
invention is illustrated. The system includes components and
features similar to the system 10 illustrated in FIG. 1. However,
in FIG. 2, the outlet 46 of the degassing tower 14 is connected in
fluid communication with the inlet 40 of the anode chamber 39 of
the electrolytic cell 12. This system 10 is different from the
system shown in FIG. 1 in that a pump (i.e., pump 16) is not used
to communicate catholyte from the degassing tower 14 into the inlet
40 of the anode chamber 39. In lieu of the pump 16 illustrated in
FIG. 1, the system 10 in FIG. 2 uses gravity to feed the catholyte
solution from the degassing tower 14 into the inlet 40 of the anode
chamber 39 of the electrolytic cell 12. Gravity feed of the
catholyte from the degassing tower 14 into the anode chamber 39 of
the electrolytic cell 12 is accomplished by positioning the inlet
44 to the degassing tower 14 at a position at least level with or
above the outlet 42 of the anode chamber 39. The flow of output
solution from the anode chamber 39 is controlled by a
non-equilibrium scenario in the head pressure established between
the volume of catholyte in the degassing tower 14 and the output
solution in the anode chamber 39 of the electrolytic cell 12. As
catholyte enters the degassing tower 14 via the inlet 44, a
reservoir of catholyte solution collects within the degassing tower
14. As the level of the reservoir reaches the level of the outlet
42 of the anode chamber, the head pressure on the reservoir of
liquid catholyte solution within the degassing chamber 14 forces
the output solution in the anode chamber 39 out the outlet 42.
Thus, as the rate of flow of catholyte into the degassing tower 14
increases, the rate at which catholyte solution flows into the
anode chamber 39 also increases. In this configuration, all the
catholyte solution produced by the cathode chamber 35 is recycled
through the anode chamber 39 of the electrolytic cell 12. The
recycling process is achieved by gravity feeding the catholyte
solution from the degassing tower 14 through the anode chamber 39.
This configuration also prevents air from being introduced into the
anode chamber 39 of the electrolytic cell 12, since liquid head
pressure is used to move the catholyte solution from the degassing
tower 14 through the anode chamber 39. While the catholyte solution
is in the degassing tower 14 hydrogen gas is released from the
solution and exits through a vent 48 into the atmosphere at
atmospheric pressure. The present invention also contemplates that
a degassing membrane with an accompanying vacuum pump may be used
in place of the degassing tower for degassing the catholyte liquid
solution at a pressure above atmospheric pressure. In this design,
the acquired hydrogen gas could be directed/diverted to another
location, release or collection point. The cell 12 could also be
designed to include a degassing membrane that operates at
atmospheric pressure and does not require a pump by using
atmospheric pressure exerted on the degassing membrane.
EXAMPLE
[0027] Embodiments of the present invention are further defined in
the following non-limiting example. It should be understood that
this example, while indicating a certain embodiment of the
invention, is given by way of illustration only. From the above
discussion and this example, one skilled in the art can ascertain
the essential characteristics of the invention, and without
departing from the spirit and scope thereof, can make various
changes and modifications of the embodiments in the invention to
adapt it to various usages and conditions. Thus, various
modifications of the embodiments of the invention, in addition to
those shown and described herein, will be apparent to those skilled
in the art from the foregoing description. Such modifications are
also intended to fall within the scope of the appended claims.
[0028] FIG. 3 is a schematic illustration of an electrolytic cell
100 configured with the combined features shown in FIG. 2 generally
within line 3-3. The cell illustrated in FIG. 3 is but one
exemplary illustration of an electrolytic cell 100 that includes
the combined components shown within the line 3-3 in FIG. 2.
According to a preferred embodiment of the invention, the
electrolytic cell 100 may be disassembled (i.e., taken apart) into
its component parts for troubleshooting, repairing or replacing
worn or damaged components, or for cleaning. The design of the
electrolytic cell 100, as discussed below, permits plumbing lines
in connection to the inlets and outlets of the cell on a single
side through a single manifold 102 that is a component part of the
electrolytic cell 100. Similar to the electrolytic cell 12 shown in
FIGS. 1-2, the electrolytic cell 100 illustrated in FIG. 3 includes
an anode chamber 104 on one side of the intermediate chamber 108
and a cathode chamber 112 on the opposite side of the intermediate
chamber 108. These chambers may be fabricated from polypropylene;
however, other materials such as polyvinyl chloride (PVC) or
polyethylene are contemplated materials of the present invention.
According to one configuration of the electrolytic cell 100, the
cathode chamber 112 is generally U-shaped. The cathode chamber 112
includes an inlet 122 and an outlet 124. The inlet to the cathode
chamber 112 is located on an external face of manifold 102. The
inlet 122 includes a flow path through the manifold 102 into the
cathode chamber 112. Similarly, the outlet 124 from the cathode
chamber 112 is a flow path in fluid communication with an inlet 126
to the degassing chamber 125. The inlet 126 of the degassing
chamber 125 is positioned or elevated above the location of the
outlet 128 to the degassing chamber 125. The outlet 128 is
connected in fluid communication through the inlet flow path 130 to
the anode chamber 104. In addition to an outlet 128 being connected
in fluid communication with the inlet 130 of the anode chamber 104,
the degassing chamber 125 includes a drain outlet 138. In one
aspect of the invention, a flow control device (e.g., a valve) may
be configured in the degassing chamber 125 to selectively close and
open liquid flow through the drain outlet 138. Similarly, a flow
control device may be used in the flow path of the degassing
chamber 125 to selectively open and close the flow path to the
outlet drain 138 to drain fluid from the anode chamber 104 and the
degassing chamber 125. The degassing chamber 125 also includes a
vent outlet 134 in the manifold 102 providing a flow path for
gasses venting from the degassing chamber 125 into the ambient
environment. The anode chamber 104 is separated from the
intermediate chamber 108 by an anode electrode 114 (e.g., such as a
coated Titanium material) and an anion exchange membrane 106.
Similarly, a cation exchange membrane 116 and a cathode electrode
110 (e.g., such as a bare Hastelloy material) separate the
intermediate chamber 108 from the cathode chamber 112. The
intermediate chamber 108 may include a support member (not shown)
as set forth in U.S. patent application Ser. No. 13/185,874 (Ecolab
USA, Inc.), which is herein incorporated by reference in its
entirety. As further illustrated in FIG. 3, an outlet 132 is
included in the manifold 102 that is in fluid communication via a
flow path to the anode chamber 104. The intermediate chamber 108
includes an inlet 118 in the manifold 102 connected in fluid
communication through a flow path with the intermediate chamber 108
and an outlet 120 in the manifold 102 also connected in fluid
communication with the intermediate chamber 108. The inlet 122 to
the cathode chamber 112 in the manifold 102 may include a drain
outlet 136 whereby liquid in the cathode chamber 112 may be
selectively drained using a flow control device (e.g., a valve) not
shown. As further illustrated in FIG. 3 and discussed above, the
inlet 126 to the degassing chamber 125 is positioned or elevated
above the level of outlet 128 in fluid communication with anode
chamber 104 via inlet 130. The inlet 126 to the degassing chamber
125 is also positioned or located at an elevation above the outlet
132 to the anode chamber 104. In operation, a body of catholyte is
reservoired between the level of the outlet 132 and the inlet 130
to the anode chamber 104. The head pressure of liquid reservoired
in the degassing chamber 125 creates flow through the outlet 132
from the head pressure resulting from gravity acting on the liquid
in the anode chamber 104. Thus, it is preferred that the inlet 126
to the degassing chamber 125 is at least at or above the level of
the outlet 132 to the anode chamber 104 to facilitate movement of
liquid through the anode chamber by gravity.
[0029] In operation, the electrolytic cell 100 provides a
water-electrolyzing device outputting alkaline sodium hypochlorite
solution, which accomplishes one or more of the objectives of the
invention by providing an increase in chlorine capture efficiency
and chlorine concentration in the output solution. In operation,
water is introduced into the electrolytic cell 100 through an inlet
122 to the cathode chamber 112. Simultaneously and continuously
during operation of the cell, an electrolyte, such as a brine
solution, is introduced into the intermediate chamber 108 through
inlet 118. Alkaline water (catholyte) is generated in the cathode
chamber 112 by loading electric current so as to electrolyze the
water in the presence of electrolyte supplied by means of
electrophoresis from the intermediate chamber 108. The catholyte,
which may consist of sodium hydroxide or potassium hydroxide and
hydrogen gas generated in the cathode chamber 112 is discharged
through outlet 124 into the degassing chamber 125 via inlet 126.
During this process, the electrolyte solution in the intermediate
chamber 108 is circulated to maintain the concentration of
electrolytes in the intermediate chamber 108. The catholyte (e.g.,
sodium hydroxide) resides in the degassing chamber 125, thereby
releasing hydrogen gas through the vent outlet 134. The alkaline
solution (catholyte) travels through the outlet 128 of the
degassing chamber 125 into the anode chamber 104 via inlet 130. The
catholyte is electrolyzed in the presence of electrolytes supplied
by means of electrophoresis from the intermediate chamber 108, and
thereby generates an alkaline sodium hypochlorite solution. This is
accomplished by converting the chlorine in the hypochlorous acid to
its ionic form, the hypochlorite ion. The head pressure created by
gravity acting on the reservoir of catholyte liquid in the
degassing chamber 125 forces this solution from the anode chamber
104 through the outlet 132 in the manifold 102 as an output
solution of the electrolytic cell 100. This process is specifically
different than a traditional electrolytic cell in that the
catholyte solution is recycled through the anode chamber instead of
passing fresh water through the anode chamber 104. Suitable
operating conditions for the electrolytic cell 100, particularly
the generation of an alkaline solution (e.g., catholyte) in the
cathode 112, is described or referred to in U.S. patent application
Ser. No. 11/438,454. According to one embodiment of the invention,
all of the catholyte produced by the cathode chamber 112 is
recirculated through the anode chamber 104 under force of gravity
acting on a reservoir of catholyte liquid in the degassing chamber
125. The electrolyte may be pumped through the intermediate chamber
108 as discussed above in the description relating to the system
shown in FIG. 1. One or more of the flow paths within the
electrolytic cell 100 may be configured with a flow control device
(e.g., a valve) to permit one or more of the flow paths to be
selectively opened or closed to drain catholyte or the output
solution from the cell. For example, catholyte may be drained from
the degassing chamber 125 via the drain outlet 138 by opening the
flow path using a flow control device (not shown). Similarly, the
solution within the anode chamber 104 may be drained through the
drain outlet 138. The manifold 102 may include one or more flow
control devices, either electrically or manually operated, for
controlling the flow through drain outlet 138 and/or drain outlet
136. In the event the catholyte in the cathode chamber 112 is
drained from the cell 100, the liquid passes through the flow path
connected in communication with the liquid with the drain outlet
136 in manifold 102. Alternatively, the flow control device may be
configured in the plumbing external to the manifold 102 whereby one
of more of the flow paths into or out of the electrolytic cell are
selectively closed or opened to inhibit or permit liquid flow into
or out of the electrolytic cell 100.
[0030] FIG. 4 is a schematic illustration of another electrolytic
cell 100 Like the electrolytic cell 100 shown in FIG. 3, the
electrolytic cell 100 shown in FIG. 4 is another exemplary
illustration of an electrolytic cell that includes the combined
components shown within the lines 3-3 in FIG. 2. The electrolytic
cell 100 includes a chamber 108 for holding an electrolyte solution
for providing cations and anions. An electrolytic solution is
provided to the chamber 108 through the inlet 118 and exits from
the cell 100 through the outlet 120. An anode chamber 104 and a
cathode chamber 112 are contained within the chamber 108. These
chambers may be fabricated from polypropylene; however, other
materials such as polyvinylchloride (PVC) or polyethylene are
contemplated materials of the present invention. The cathode
chamber 112 includes an inlet 122 and an outlet 124. The inlet to
the cathode chamber may be located on an external face of the
manifold 102. The inlet 122 includes a flow path through the
manifold 102 into the cathode chamber 112. Similarly, the outlet
124 from the cathode chamber 112 is a flow path in fluid
communication with an inlet to the degassing chamber 125. The inlet
126 of the degassing chamber 125 is positioned or elevated above
the location of the outlet 128 to the degassing chamber 125. The
outlet 128 is connected in fluid communication through the inlet
flow path 130 to the anode chamber 104. In addition to an outlet
128 being connected in fluid communication with the inlet 130 of
the anode chamber 104, the degassing chamber includes a drain
outlet 138. The degassing chamber 125 includes a vent outlet 134
that provides a flow path for gasses venting from the degassing
chamber 125 into the ambient environment at atmospheric pressure.
The anode chamber 104 is separated from the electrolytic solution
in chamber 108 by an anode electrode 114 (e.g., such as coated
titanium material) and an anion exchange membrane 106. Similarly, a
cation exchange member 116 and a cathode electrode 110 (e.g., such
as bare Hastelloy) separate the cathode chamber from the
electrolytic solution in chamber 108. The electrolytic solution
(e.g., brine) in the reservoir of chamber 108 serves as a source of
anions and cations that are transferred into the anode chamber 104
and cathode chamber 112, respectively, by electrophoresis. Similar
to the design shown in FIG. 3, an outlet 132 in the manifold 102 is
connected in fluid communication via flow path to the anode chamber
104. Chamber or reservoir 108 includes an inlet 118 in the manifold
102 connected in fluid communication through a flow path with the
chamber or reservoir 108 and an outlet 120 in the manifold 102 also
connected in fluid communication with the chamber or reservoir 108.
The inlet 122 to the cathode chamber 112 in the manifold 102 may
include a drain outlet 136 whereby liquid in the cathode chamber
112 may be selectively drained using a flow control vice (e.g., a
valve) not shown. The inlet 126 to the degassing chamber 125 is
positioned or elevated above the level of the outlet 128 in fluid
communication with the anode chamber 124 via inlet 130. The inlet
126 to the degassing chamber 125 is also positioned or located at
an elevation above the outlet 132 to the anode chamber 104. In
operation, a body of catholyte is reservoired between the level of
the outlet 132 and the inlet 130 to the anode chamber 104. Gas
bubbles (e.g., hydrogen gas) are separated from the catholyte at
the point where the catholyte liquid enters the degassing tower
inlet 144 with the gas being vented and the degassed fluid falling
by gravity to the accumulation chamber at the bottom of the
degassing tower. The head pressure of the liquid reservoir in the
degassing chamber 125 creates flow through the anode chamber 104
and outlet 132 of the anode chamber. Thus, it is preferred that the
inlet 126 to the degassing chamber 125 is at least at or above the
level of the outlet 132 to the anode chamber 104 to facilitate
movement of liquid through the anode chamber 104 by gravity. Thus,
as addressed above, the electrolytic cell may consist of as few as
two chambers or more than two chambers to perform the process of
electrophoresis.
[0031] FIGS. 10-13 illustrate plots showing data acquired by
exploratory testing of an electrolytic cell 100 according to the
exemplary embodiments of the invention which are shown. The
electrolytic cell 100 configured to recycle catholyte into the
anode chamber 104 from the cathode chamber 112 demonstrated
improved efficiencies over traditional cells that do not recycle
the catholyte into the anode chamber. In particular, the
electrolytic cell produced an output solution having a higher pH
using less electrical current than traditional cells where the
catholyte is not recycled through the anode chamber 104.
[0032] FIG. 11 illustrates another plot of chlorine capture versus
the electrical current applied to the electrodes for achieving
electrolysis. The plot illustrates evidence of the invention
meeting its objectives by providing increased chlorine capture
using less electrical current by recycling catholyte from the
cathode chamber through the anode chamber 104, as illustrated in
the embodiments identified in the invention. Note that less
chlorine is captured at the expense of the same current using the
traditional method of introducing water into both of the cathode
chamber 112 and anode chamber 104 and producing a working solution
in a post-mixing arrangement.
[0033] FIG. 12 provides a plot illustrating further evidence of the
increase in chlorine capture rate accomplished by recycling the
catholyte from the cathode chamber 112 through the anode chamber
104.
[0034] Lastly, the plot in FIG. 13 illustrates the efficiency of
the electrolytic cell of this invention given the amount of
electrical current required to operate the cell and produce the
same results. Note that the electrolytic cell using 100% catholyte
recycle more efficiently uses the same amount of current provided
to the electrodes than the traditional no-recycle configuration
that generates chlorine solutions by electrolysis accompanied by a
post-mixing operation.
[0035] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the inventions
and all such modifications are intended to be included within the
scope of the following claims.
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