Process for nitrous oxide purification

1. A method for purification of a nitrous oxide gas containing O 2 , said method comprising:

feeding said nitrous oxide gas and a reducing agent selected from the group consisting of hydrogen, carbon monoxide, ammonia and mixtures thereof into a de-oxidation reactor;

performing de-oxidation by reacting said reducing agent with O 2 using a de-oxidation catalyst selected from the group consisting of palladium, platinum and mixtures thereof to form an inert, in order to deplete said O 2 in said nitrous oxide gas, while limiting the amount of nitrous oxide removed from said nitrous oxide gas.

2. A method according to claim 1 , wherein said reducing agent is hydrogen.

3. A method according to claim 1 , wherein said inert comprises water or carbon dioxide.

4. A method according to claim 1 , wherein said inert is water.

5. A method according to claim 1 , wherein said nitrous oxide gas further comprises NOx, nitrogen, carbon monoxide, carbon dioxide or organic compounds.

6. A method according to claim 5 , wherein said NOx is removed from said nitrous oxide gas by selective catalytic reduction using ammonia or a precursor thereof and a selective catalytic reduction catalyst.

7. A method according to claim 6 , wherein said selective catalytic reduction catalyst is selected from the group consisting of oxides of vanadium, titanium and mixtures thereof.

8. A method according to claim 6 , wherein said selective catalytic reduction is performed in a selective catalytic reduction reactor separate from said de-oxidation reactor.

9. A method according to claim 8 , wherein said selective catalytic reduction reactor is a lateral flow reactor.

10. A method according to claim 6 , wherein steam is used as a carrier gas for said nitrous oxide gas during said selective catalytic reduction.

11. A method according to claim 6 , wherein prior to said selective catalytic reduction, an oxygen containing gas is passed over said selective catalytic reduction catalyst.

12. A method according to claim 5 , wherein said carbon monoxide and organic compounds are removed from said nitrous oxide gas during said de-oxidation.

13. A method according to claim 1 , wherein said nitrous oxide gas comprises adipic acid off-gas.

14. A method according to claim 13 , wherein said off-gas comprises between 1000 ppmv and 10 vol. % O 2 , and between 100 ppmv and 1% NOx.

15. A method according to claim 1 , wherein up to 99 vol. % of said O 2 is removed from said nitrous oxide gas.

16. A method according to claim 1 , wherein said de-oxidation step is performed with more than one reactor.