A method for reducing nitrogen oxide emissions of a recovery boiler, and a recovery boiler

摘要

A method for reducing nitrogen oxides of a recovery boiler, and a recovery boiler, where the furnace (2) of the recovery boiler is supplied with primary air from primary air nozzles (4), black liquor from liquor nozzles (6a, 6b), secondary air from secondary air nozzles (5) above the primary air nozzles (4) but still below the liquor nozzles (6a, 6b), tertiary air from tertiary air nozzles (7) above the liquor nozzles (6a, 6b), and quaternary air from quaternary air nozzles (8) above the tertiary air nozzles (7). Black liquor is supplied to the furnace (2) from first liquor nozzles (6a) and second liquor nozzles (6b), which liquor nozzles (6a, 6b) are arranged substantially on the same level with respect to the height of the furnace (2), and the droplet size of liquor fed from the second liquor nozzles (6b) is substantially smaller than the droplet size of liquor fed from the first liquor nozzles (6a).