ELECTROLYTIC CELL WITH CATHOLYTE RECYCLE
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.
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 INVENTIONThe 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 INVENTIONThe 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.
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.
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.
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.
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.
A further object of the invention is to accomplish catholyte recycling by gravity feed.
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 INVENTIONIn 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.
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.
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.
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.
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.
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.
As illustrated in
In
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.
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
Lastly, the plot in
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.
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.
Type: Application
Filed: Oct 31, 2014
Publication Date: Feb 26, 2015
Inventors: Scott R. Limback (St. Paul, MN), Barry R. Taylor (Adrian, MI), Kevin A. Wuebben (Apple Valley, MN), Marvin C. Trulsen (Woodbury, MN), Lylien Tan (Maplewood, MN)
Application Number: 14/529,233
International Classification: C25B 1/26 (20060101); C25B 9/00 (20060101); C25B 15/08 (20060101);