Wet scrubbing apparatus and method for controlling NOx emissions

• US 7,214,356 B2
• Filed: 10/01/2003
• Issued: 05/08/2007
• Est. Priority Date: 07/09/2003
• Status: Expired due to Term

• Current Assignee: Belco Technologies Corporation (Corteva, Inc.)
• Original Assignee: Belco Technologies Corporation (Corteva, Inc.)
• Inventors: Morin, Andrew, Hsieh, Joseph, Philibert, Dominique, Gilman, Kevin R., Eagleson, Scott
• Primary Examiner(s): Johnson; Edward M.
• Application Number:
  US10/677,052
• Publication Number:
  US 20050008555A1
• Time in Patent Office: 1,315 Days
• Field of Search: 423/235, 423/239.1
• 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. A method of controlling NOx emissions comprising:

permitting flue gas to enter an interior of a chamber;

quenching flue gas to lower the temperature of the flue gas;

injecting ozone into an ozone injection zone of the interior of the chamber;

spraying a liquid towards the walls of the chamber to capture reaction products of the oxidation process; and

maintaining a portion of the ozone injection zone of the chamber substantially free of droplets of the liquid.

2. The method according to claim 1, wherein the liquid includes a sodium, calcium, or magnesium reagent.

3. A method according to claim 1, wherein the injection of ozone into the interior of the chamber occurs below the spraying the liquid, and the entrance of a flue gas is below spraying the liquid.

4. A method according to claim 1, wherein the spraying of a liquid includes the step of injecting a liquid through 3 or more spray nozzles.

5. A method according to claim 1, further comprising maintaining a liquid to gas ratio between 5–

80 gallons per 1000 feet³ of gas flow.

6. A method according to claim 1, further comprising allowing flue gas to travel through the apparatus at a rate from 3–

26 feet per second.

7. A method according to claim 1, wherein NOx emissions are less than 40 ppmdv.

8. A method according to claim 3, further comprising maintaining a percentage of NOx removal that is greater than or equal to 50%.

9. A method according to claim 1, further comprising quenching the flue gas to a temperature of between 120°

–

80°

F.

10. A method according to claim 1, wherein the quenching of the flue gas occurs at the entrance into the interior of the chamber, and includes spraying liquid through the gas as it enters the chamber.

11. A method of controlling NOx emissions comprising the steps of:

introducing a flue gas into a chamber;

quenching flue gas;

injecting ozone into an ozone injection and retention zone in the interior of the chamber;

spraying a liquid towards the walls of the chamber to capture reaction products of the oxidation process so as to maintain a substantially droplet-free chamber interior in the vicinity of the ozone injection and retention zone.

12. A method according to claim 11, wherein the injecting ozone into the interior of the chamber occurs prior to spraying a liquid.

13. A method according to claim 11, wherein spraying the liquid comprises spraying the liquid through 3 or more spray nozzles.

14. A method according to claim 11, further comprising maintaining a liquid to gas ratio between 5–

80 gallons per 1000 feet³ of gas flow.

15. A method according to claim 11, further comprising allowing flue gas to travel through the apparatus at a rate of from 3–

26 feet/second.

16. A method according to claim 11, wherein NOx emissions are less or equal to 50 ppmdv.

17. A method according to claim 11, further comprising maintaining a percentage of NOx removal greater than or equal to 50%.

18. A method according to claim 11, further comprising quenching the flue gas to a temperature of between 140°

–

160°

F.

19. A method of dontrolling NOx emissions comprising:

permitting flue gas to enter an interior of a chamber;

spraying a quenching liquid toward the walls of the chamber to lower the temperature of the flue gas;

injecting ozone into an ozone injection zone of the interior of the chamber; and

maintaining a portion of the ozone injection zone of the chamber substantially free of droplets of the quenching liquid.

20. The method of claim 19 further comprising the step of spraying a product-capturing liquid towards the walls of the chamber to capture reaction products of the oxidation process.

21. A method of controlling NOx emissions comprising:

permitting flue gas to enter an interior of a chamber;

spraying a product-capturing liquid towards the walls of the chamber to capture reaction products of the oxidation process;

injecting ozone into an ozone injection zone of the interior of the chamber; and

maintaining a portion of the ozone injection zone of the chamber substantially free of droplets of the product-capturing liquid.

22. The method of claim 21 further comprising the step of spraying a quenching liquid toward the walls of the chamber to lower the temperature of the flue gas.