US Patent 7534400 Wet scrubbing apparatus for controlling NOx emission

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.