Point-of-use generation of chlorinated alkaline cleaning solutions by electrolysis

• US 6,719,891 B2
• Filed: 11/21/2001
• Issued: 04/13/2004
• Est. Priority Date: 11/21/2001
• Status: Expired due to Term

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Ecolab, Inc.
• Inventors: Ruhr, Richard, Anderson, Bryan, Schilling, Joel, Peitersen, Nathan, Matson, Harold, Peters, Sara, Pankratz, Paul, Shulman, Mike
• Primary Examiner(s): Phasge, Arun S.
• Application Number:
  US09/990,134
• Publication Number:
  US 20030098244A1
• Time in Patent Office: 874 Days
• Field of Search: 205/500, 205/620, 205/687
• US Class Current: 205/500
• CPC Class Codes: A61L 2/035 Electrolysis
• CPC Class Codes: A61L 2/18 Liquid substances or solutions comprising solids or dissolved gases
• CPC Class Codes: C02F 1/4674 with halogen or compound of halogens, e.g. chlorine, bromine
• CPC Class Codes: C02F 2201/46115 Electrolytic cell with membranes or diaphragms
• CPC Class Codes: C02F 2201/4612 Controlling or monitoring
• CPC Class Codes: C02F 2209/06 pH
• CPC Class Codes: C11D 17/041 Compositions releasably affixed on a substrate or incorporated into a dispensing means
• CPC Class Codes: C11D 3/044 Hydroxides or bases
• CPC Class Codes: C11D 3/3956 Liquid compositions
• CPC Class Codes: C25B 9/00 Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features

Abstract

An on-site apparatus and method for preparing aqueous cleaning compositions, including an electrolytic cell for producing and dispensing chlorine and sodium hydroxide for use in various cleaning and/or sanitizing formulations at the point of use.

Claims

1. A process for generating cleaning compositions selected from the groan consisting of sanitizers and bleaches at the point of use, the process including a dispensing system for mixing a plurality of concentrated chemical compositions according to a predetermined recipe, the recipe providing at least one concentrated chemical composition including at least one of a buffer, a surfactant, a solvent or a water conditioning agent and combining said concentrated chemical composition with chlorine, sodium hydroxide, or mixture thereof, wherein said process employs an on-site generator of chlorine and sodium hydroxide by electrolysis of a sodium chloride solution, wherein the sanitizers are formed at a pH of about 4 to about 7, and the bleaches are formed at a pH of about 9 or higher by combining sodium hydroxide and chlorine formed during said process.

2. The process of claim 1 wherein said dispensing system has a delivery system for delivering chlorine.

3. The process of claim 2 wherein said chlorine is delivered into a liquid chemical composition having a pH of about 4.5.

4. The process of claim 1 wherein said chlorine is delivered into a liquid chemical composition having a pH of about 4 to about 5.

5. The process of claim 1 wherein said dispensing system has a delivery system for delivering sodium hydroxide.

6. The process of claim 1 wherein said chlorine and said sodium hydroxide are delivered to a common vessel to produce a chemical composition having a pH of about 9 or greater.

7. The process of claim 1 wherein said concentrated chemical composition is diluted with water at a ratio of up to 1:

400.

8. The process of claim 1 wherein said on-site generator is an electrolytic cell.

9. The process of claim 8 wherein said electrolytic cell is a diaphragm cell, a bipolar diaphragm cell, a membrane cell or a mercury cell.

10. The process of claim 8 wherein said electrolytic cell is a membrane cell.

11. The process of claim 1 wherein said bleaches are formed by combining sodium hydroxide formed during said process with said chlorine fanned during said process, wherein said sodium hydroxide is combined in said bleach at a concentration of about 0.1 wt-% to about 1.5 wt-% and said chlorine is combined in said bleach at a concentration of about 5 wt-% or more available chlorine.

12. The process of claim 11 wherein said sodium hydroxide in said bleach is about 0.5 wt-% and said available chlorine in said bleach is about 1.5 wt-% to about 10 wt-%.

13. A process for manufacturing cleaning solutions comprising the steps of:

a) generating chlorine, sodium hydroxide, or a mixture thereof using an electrolytic coil;

b) collecting chlorine in a first vessel and sodium hydroxide in a second vessel;

c) providing a plurality of concentrated chemical compositions in a plurality of vessels, each vessel storing one of said plurality of concentrated chemical compositions;

d) selecting a predetermined cleaning composition selected from the group consisting of sanitizers at a pH of about 4 to about 7 and bleaches at a of about 9 or higher to be produced using a microprocessor controller, the predetermined cleaning composition including a predetermined amount of at least one of said plurality of concentrated chemical compositions and a predetermined amount of at least one of chlorine, sodium hydroxide, or mixture thereof; and

e) directing said predetermined amount of said at least one of said plurality of concentrated chemical compositions, and said predetermined amount of at least one of said chlorine, sodium hydroxide, or mixture thereof into a vessel thereby generating a desired cleaning composition.

14. The process of claim 13 wherein said electrolytic cell comprises an anode compartment, a cathode compartment, and a membrane separating the two compartments.

15. The process of claim 13 wherein said chlorine gas enters a solution buffered to a pH of about 4.5.

16. The process of claim 15 wherein said solution is buffered with mono-, di-, or tri-, sodium or potassium phosphates, sodium or potassium citrates, or mixtures thereof.

17. The process of claim 13 wherein said chlorine gas enters a solution buffered to a pH of about 4 to about 5 producing hypochlorous acid as a primary species.

18. The process of claim 17 wherein said solution is buffered with sodium citrate, potassium citrate, or mixture thereof.

19. The process of claim 13 wherein before step 3) said chlorine and said sodium hydroxide are mixed and said resultant composition has a pH of greater than about 9 producing sodium hypochlorite as the primary species.

20. The process of claim 13 further comprising the step of diluting said cleaning composition with water.

21. The process of claim 13 wherein said predetermined amount of sodium hydroxide delivered is about 0.1 wt-% to about 1.5 wt-% and said predetermined amount of available choline delivered is about 5 wt-% or greater.

22. The process of claim 21 wherein said predetermined amount of sodium hydroxide delivered is about 0.5 wt-% and said predetermined amount of available chlorine delivered is about 1.5 wt-% to about 10 wt-%.

23. An apparatus for the preparation of multi-component chemical cleaning compositions at the point of use comprising:

a) at least one electrolytic cell for generating at least one of chlorine, sodium hydroxide or mixture thereof;

b) a plurality of concentrated chemical compositions in a plurality of vessels, each vessel storing one of said plurality of concentrated chemical compositions;

c) a controller for selecting a predetermined amount of at least one of a plurality of concentrated chemical compositions; and

d) a delivery system in communication with said controller wherein said delivery system delivers said predetermined amount of said at least one of sodium hydroxide, chlorine, or mixture thereof and said predetermined amount of at least one of said plurality of chemical compositions to a common vessel, said combination of sodium hydroxide, chlorine, and said plurality of chemical compositions are combined to form at least one of a sanitizer having a pH of about 4 to about 7, a bleach having a pH of about 9 or greater, or both.

24. The apparatus of claim 23 further comprising a computer configured to download the desired cleaning composition to the controller.

25. The apparatus of claim 23 wherein at least one of said plurality of chemical compositions has a pH of about 4.5.

26. The apparatus of claim 23 wherein at least one of said plurality of chemical compositions has a pH of about 4 to about 5 and said chlorine is delivered to said composition having a pH of about 4 to about 5.

27. The apparatus of claim 23 having an additional delivery system and an addition vessel wherein said additional delivery system delivers chlorine and sodium hydroxide to said additional vessel to produce a mixture having a pH of about 9.

28. The apparatus of claim 23 wherein said electrolytic cell is a diaphragm cell, a bipolar diaphragm cell, a membrane cell or a mercury cell.

29. The apparatus of claim 23 wherein said predetermined amount of sodium hydroxide delivered is about 0.1 wt-% to about 1.5 wt-% and said predetermined amount of available chlorine delivered is about 5 wt-% or greater.

30. The apparatus of claim 23 wherein said predetermined amount of sodium hydroxide delivered is about 0.5 wt-% and said predetermined amount of available chlorine delivered is about 1.5 wt-% to about 10 wt-%.