Wet scrubbing apparatus and method for controlling NOx emissions

• US 20070189949A1
• Filed: 03/28/2007
• Published: 08/16/2007
• Est. Priority Date: 07/09/2003
• Status: Active Grant

• Current Assignee: Belco Technologies Corporation (Corteva, Inc.)
• Original Assignee: Belco Technologies Corporation (Corteva, Inc.)
• Inventors: Morin, Andrew, Hsieh, Joseph, Philibert, Dominique, Eagleson, Scott, Gilman, Kevin
• Granted Patent: US 7,534,400 B2
• Time in Patent Office: Days
• US Class Current: 423/235
• CPC Class Codes: B01D 2251/104 Ozone
• CPC Class Codes: B01D 2257/402 Dinitrogen oxide
• CPC Class Codes: B01D 2257/404 Nitrogen oxides other than dinitrogen oxide
• CPC Class Codes: B01D 53/56 Nitrogen oxides B01D53/60 takes precedence
• CPC Class Codes: B01D 53/79 Injecting reactants
• CPC Class Codes: Y02C 20/10 of nitrous oxide (N2O)

Abstract

An apparatus for controlling NOx emissions which includes a chamber having a wall surface and an interior, a flue gas entrance and a flue gas exit for a flue gas to enter and exit the interior of the chamber, a gas quenching zone in which the temperature of the gas can be lowered, an ozone injection and retention zone in the chamber, and a liquid spray zone including at least one spray nozzle for spraying a liquid towards the wall surface.

Claims

1. An apparatus for controlling NOx emissions comprising:

a chamber having a wall surface and an interior;

a flue gas entrance and a flue gas exit for a flue gas to enter and exit said interior of said chamber;

a gas quenching zone in which the temperature of the gas can be lowered;

an ozone injection and retention zone in said chamber; and

a liquid spray zone including at least one spray nozzle for spraying a liquid towards the wall surface so that a portion of said ozone injection and retention zone is substantially free of liquid droplets.

2. An apparatus according to claim 1, further including:

an ozone supply;

an ozone injection nozzle to inject a predetermined amount of ozone into said ozone injection and retention zone;

a liquid supply in said liquid spray zone;

a gas quenching liquid supply; and

at least one gas quenching nozzle.

3. An apparatus according to claim 2, wherein said liquid spray zone is located above said ozone injection and retention zone, and said flue gas entrance is below said liquid spray zone.

4. An apparatus according to claim 2, wherein said liquid spray zone of said apparatus is located below said ozone injection and retention zone, and said flue gas entrance and said gas quenching zone are above said liquid spray zone.

5. An apparatus according to claim 2, wherein said liquid comprises a calcium, magnesium, or sodium reagent.

6. An apparatus according to claim 2, wherein said ozone injection and retention zone has a length that is sufficient to permit a flue gas traveling through said ozone injection and retention zone a residence time ranging from 0.5-10 seconds.

7. An apparatus according to claim 6, wherein said length is sufficient to permit said flue gas to have a residence time of about 3-7 seconds in said ozone injection and retention zone.

8. An apparatus according to claim 2, wherein said flue gas is quenched to a temperature of below 200°

F. in said gas quenching zone.

9. An apparatus according to claim 2, wherein said gas quenching nozzle sprays a liquid towards the wall surface, so that a portion of said ozone injection and retention zone is substantially free of liquid droplets.

10. An apparatus for controlling NOx emissions comprising:

a chamber having a wall surface and an interior;

a flue gas entrance and a flue gas exit for a flue gas to enter and exit said interior of said chamber;

a gas quenching zone in which the temperature of the gas can be lowered;

an ozone injection and retention zone in said chamber; and

a liquid spray zone in said chamber,

said gas quenching zone including at least one spray nozzle for spraying a liquid towards the wall surface, so that a portion of said ozone injection and retention zone is substantially free of liquid droplets.

11. An apparatus according to claim 10, further including:

an ozone supply;

an ozone injection nozzle to inject a predetermined amount of ozone into said ozone injection and retention zone;

a liquid supply in said liquid spray zone;

a gas quenching liquid supply; and

at least one gas quenching nozzle.

12. An apparatus according to claim 11, wherein said liquid spray zone is located above said ozone injection and retention zone, and said flue gas entrance is below said liquid spray zone.

13. An apparatus according to claim 11, wherein said liquid spray zone of said apparatus is located below said ozone injection and retention zone, and said flue gas entrance and said gas quenching zone are above said liquid spray zone.

14. An apparatus according to claim 11, wherein said ozone injection and retention zone has a length that is sufficient to permit a flue gas traveling through said ozone injection and retention zone a residence time ranging from 0.5-10 seconds.

15. An apparatus according to claim 14, wherein said length is sufficient to permit said flue gas to have a residence time of about 3-7 seconds in said ozone injection and retention zone.

16. An apparatus according to claim 11, wherein said flue gas is quenched to a temperature of below 200°

F. in said gas quenching zone.

17. An apparatus according to claim 11, wherein said gas quenching nozzle sprays a liquid towards the wall surface, so that said ozone and injection and retention zone is substantially free of liquid droplets.

18. A combustion system comprising:

a boiler; and

an apparatus for controlling NOx emissions comprising;

a chamber having a wall surface and an interior;

a flue gas entrance and a flue gas exit for a flue gas to enter and exit said interior of said chamber;

a gas quenching zone in which the temperature of the gas can be lowered;

an ozone injection and retention zone in said chamber; and

a liquid spray zone including at least one spray nozzle for spraying a liquid towards the wall surface so that a portion of said ozone injection and retention zone is substantially free of liquid droplets.

19. An apparatus according to claim 18, further including:

an ozone supply;

an ozone injection nozzle to inject a predetermined amount of ozone into said ozone injection and retention zone;

a liquid supply in said liquid spray zone;

a gas quenching liquid supply; and

at least one gas quenching nozzle.

20. An apparatus according to claim 19, wherein said liquid spray zone is located above said ozone injection and retention zone, and said flue gas entrance is below said liquid spray zone.

21. An apparatus according to claim 19, wherein said liquid spray zone of said apparatus is located below said ozone injection and retention zone, and said flue gas entrance and said gas quenching zone are above said liquid spray zone.

22. An apparatus according to claim 19, wherein said ozone injection and retention zone has a length that is sufficient to permit a flue gas traveling through said ozone injection and retention zone a residence time ranging from 0.5-10 seconds.

23. An apparatus according to claim 22, wherein said length is sufficient to permit said flue gas to have a residence time of about 3-7 seconds in said ozone injection and retention zone.

24. An apparatus according to claim 19, wherein said gas quenching nozzle sprays a liquid towards the wall surface, so that a portion of said ozone injection and retention zone is substantially free of liquid droplets.

25. A combustion system comprising:

a boiler; and

an apparatus for controlling NOx emissions comprising;

a chamber having a wall surface and an interior;

a flue gas entrance and a flue gas exit for a flue gas to enter and exit said interior of said chamber;

a gas quenching zone in which the temperature of the gas can be lowered;

an ozone injection and retention zone in said chamber; and

a liquid spray zone in said chamber,

said gas quenching zone including at least one spray nozzle for spraying a liquid towards the wall surface so that a portion of said ozone injection and retention zone is substantially free of liquid droplets.