| 摘要 |
PURPOSE: To reduce NOX concentration by controlling the addition volume of ammonia necessary for giving a reduced NOX concentration as desired in the flue gas being emitted into the atmosphere so that the amount of unreacted ammonia will not be excess. CONSTITUTION: A flue gas flow containing NOX of about at least 20 parts by volume per flue gas (11) of 1 million parts by volume is taken out of a burning process, to which ammonia gas is controllably added from a nozzle (17). The flue gas flow is then introduced into a catalytic denitrification unit (18) containing a denitrification catalyst material, where the NOX concentration is reduced. Based on the comparison of NOX concentration measured in the flue gas in the downflow side of the unit (18) and a desirable NOX concentration, a trim signal is gained. And, while controlling the addition volume of ammonia necessary for giving a reduced NOX concentration as desired in the flue gas being emitted into the atmosphere, an additional spray volume of ammonia is fed based on the trim signal. |
