Wet scrubbing apparatus and method for controlling NOx emissions
View Patent ↗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.
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 feet 3 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 feet 3 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.