Process for production of chlorine dioxide

1 . A process for production of chlorine dioxide comprising;

reacting in an aqueous reaction medium in a reaction vessel an alkali metal chlorate or chloric acid and methanol to generate chlorine dioxide,

withdrawing from the reaction vessel a gas comprising chlorine dioxide and gaseous by-products,

condensing part of the gas withdrawn to obtain a condensate; and

removing said condensate from the non-condensed gas without re-circulating it back to the process for production of chlorine dioxide.

2 . A process according to claim 1 , wherein said reaction medium is maintained at a temperature from about 15° C. to about 100° C.

3 . A process according to any one of the claim 1 or 2 , wherein said reaction medium is maintained at an acidity from about 2 to about 11 N.

4 . A process according to any one of the preceding claims, wherein the reaction medium is maintained at a temperature and pressure corresponding to its boiling point.

5 . A process according to any one of the preceding claims, wherein the reaction medium is maintained at a pressure from about 8 to about 80 kPa.

6 . A process according to any one of the preceding claims, further comprising precipitating solid alkali metal sulfate in the reaction medium.

7 . A process according to any one of the preceding claims, wherein said gaseous by-products withdrawn from the reaction vessel comprise formic acid.

8 . A process according to any one of the preceding claims, wherein part of the gas withdrawn from the reaction vessel is condensed at a temperature from about 2 to about 50° C.

9 . A process according to claim 8 , wherein part of the gas withdrawn from the reaction vessel is condensed at a temperature from about 15 to about 35° C.

10 . A process according to any one of the preceding claims, wherein a part of or all the removed condensate is used in a bleaching process.

11 . A process according to any one of the preceding claims, wherein a part of or all the removed condensate is used as a biocide.

12 . A process according to any one of the preceding claims, further comprising bringing said non-condensed gas, after removal of the condensate, to an absorption tower, where it is contacted with a flow of water to form an aqueous solution containing chlorine dioxide.

13 . A process according to claim 12 , further comprising bringing said aqueous solution containing chlorine dioxide to a storage tank.

14 . A process according to any one of the preceding claims, further comprising concentrating the condensate by membrane separation or azeotropic distillation.

15 . A process according to any one of the preceding claims, further comprising removing the chlorine dioxide from the condensate and using a resulting formic acid or formiate solution as a chemical feed in a bio treatment system.