Claims
- 1. A process for producing chloride dioxide comprising the steps of:(a) forming an aqueous premixture of from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and at least lone of a protective colloid, a radical scavenger of a phosphonic acid based complexing agent, wherein the pH of the premixture is from about 1 to about 4, said premixture having a rate of decomposition of hydrogen peroxide of no more than 5% by weight after fourteen days; (b) storing said premixture in a vessel; (c) transporting said stored premixture to a chlorine dioxide site having a reactor; (d) feeding a mineral acid and said transported premixture to said reactor; (e) reducing chlorate ions in the reaction mixture in said reactor to form chlorine dioxide, wherein the degree of chlorate conversion to chlorine dioxide in said reactor is from about 75% to 100%; and (f) recovering a product Containing chlorine dioxide from said reactor.
- 2. A process as claimed in claim 1, wherein said process is continuous.
- 3. A process as claimed in claim 1, wherein said chlorine dioxide reactor is a tubular reactor, and wherein step (d) comprises feeding said premixture and said mineral acid to a first end of said tubular reactor, aid wherein step (f) comprises recovering a product containing chlorine dioxide at a second end of said tubular reactor.
- 4. A process as claimed in claim 1, wherein said premixture includes at least one phosphonic acid based complexing agent.
- 5. A process as claimed in claim 1, wherein said premixture includes at least on protective colloid.
- 6. A process as claimed in claim 5, wherein said at least one protective colloid comprises a tin compound.
- 7. A process as claimed in claim 1, wherein said premixture comprises from about 40 to about 55 wt % water.
- 8. A process as claimed in claim 1, wherein the pH of said premixture is from about 1.5 to about 3.5.
- 9. A process as claimed in claim 1, wherein the mineral acid is sulfuric acid.
- 10. A process as claimed in claim 1, wherein the product recovered in step (c) is an aqueous solution containing chlorine dioxide, oxygen and an alkali metal salt of the mineral acid.
- 11. A process as claimed in claim 1, wherein said premixture has a chloride ion content, of less than about 0.5 wt % calculated as NaCl in NaClO3.
- 12. A process as claimed in claim 1, wherein said premixture comprises from about 0.1 to about 5 moles per liter of said phosphonic acid based complexing agent.
- 13. A process for producing chloride dioxide comprising the steps of:(a) forming an aqueous premixture of from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and at least one of a protective colloid, a radical scavenger or a phosphonic acid based complexing agent, wherein the pH of the premixture is from about 1 to about 4, said premixture having a rate of decomposition of hydrogen peroxide of no more than about 5% by weight after fourteen days; (b) transporting said premixture to a chlorine dioxide reactor site having a reactor; (c) storing said transported premixture on said site; (d) feeding a mineral acid and said premixture to said reactor; (e) reducing chlorate ions in the reaction mixture in said reactor to form chlorine dioxide, wherein the degree of chlorate conversion to chlorine dioxide in said reactor is from about 75% to 100%; and (f) recovering a product containing chlorine dioxide from said reactor.
- 14. A process as claimed in claim 13, wherein said process is continuous.
- 15. A process as claimed in claim 13, wherein said chlorine dioxide reactor is a tubular reactor, and wherein step (d) comprises feeding said premixture, and said mineral acid to a first end of said tubular reactor and wherein step (f) comprises recovering a product containing chlorine dioxide at a second end of said tubular reactor.
- 16. A process as claimed in claim 13, wherein said premixture includes at least one phosphonic acid based complexing agent.
- 17. A process as claimed in claim 13, wherein said premixture includes at least one protective colloid.
- 18. A process as claimed in claim 17, wherein said at least one protective colloid includes a tin compound.
- 19. A process as claimed in claim 13, wherein said premixture includes at least one radical scavenger.
- 20. A process as claimed in claim 13, wherein said premixture comprises from about 0.1 to about 5 moles per liter of said phosphonic acid based complexing agent.
- 21. A process as claimed in claim 13, wherein said phosphonic acid based complexing agent is selected from the group consisting of 1-hydroxyethylidene-1-1,2-diphosphonic acid, 1-aminoethane-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylene diamine tetra (methylenephosphonic acid), hexamethylene diamine tetra (methylenephosphonic acid), diethylenetriamine penta (methylenephosphonic acid), diethylenetriamine hexa (methylenephosphonic acid), morpholinomethane diphosphonic acid, N,N-dimethyl aminodimethyl diphosphonic acid, aminomethyl diphosphonic acid, and salts thereof.
- 22. A process as claimed in claim 13, wherein said premixture comprises from about 40 to about 55 wt % water.
- 23. A process as claimed in claim 13, wherein said premixture comprises from about 1 to about 10 mmoles per liter of alkali metal nitrate.
- 24. A process as claimed in claim 13, wherein the content of chloride ions in said premixture is less than about 0.5 mmoles per liter.
- 25. A process as claimed in claim 13, wherein the molar ratio of H2O2 to ClO3− in the premixture is from about 0.2:1 to about 2:1.
- 26. A process as claimed in claim 13, wherein the premixture comprises from about 3 to about 6 moles/liter of alkali metal chlorate, from about 3 to about 5 moles/liter of hydrogen peroxide and from about 0.5 to about 3 mmoles/liter of at least one phosphonic acid based complexing agent.
- 27. A process as claimed in claim 13, wherein the pH of said premixture is from about 1.5 to about 3.5.
- 28. A process as claimed in claim 13, wherein the mineral acid is sulfuric acid.
- 29. A process as claimed in claim 13, wherein the product recovered in step (c) is an aqueous solution containing chlorine dioxide, oxygen and an alkali metal salt of the mineral acid.
- 30. A process as claimed in claim 13, wherein said premixture has a chloride ion content of less than about 0.5 wt % calculated as NaCl in NaClO3.
Parent Case Info
This application is a division of application Ser. No. 09/390,321 filed Sep. 7, 1999 which is a continuation-in-part of application Ser. No. 09/330,074 filed Jun. 11, 1999, now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2307818 |
May 2000 |
CA |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09/330374 |
Jun 1999 |
US |
Child |
09/390321 |
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US |