| 摘要 |
PROBLEM TO BE SOLVED: To realize a highly efficient denitrification with restricting discharge of unreacted NH3 by using a reduced amount of catalyst. SOLUTION: Boiler combustion exhaust gas from a furnace 8 is guided into a denitrification apparatus 1 where a flow is formed in a perpendicular (vertical) direction, and in the denitrification apparatus 1 denitrification catalyst 4 and NH3 decomposing catalyst 2 are arranged in this order from an upstream side with respect to the boiler combustion exhaust gas. A NH3 injecting apparatus 6 is provided in a front stream side of the denitrification apparatus 4 and an air injecting apparatus 5 for injecting outlet air of an air heater 7 is installed between the denitrification catalyst 4 and the NH3 decomposing catalyst 2. Because the air injecting apparatus 5 for injecting the outlet air of the air heater 7 is provided between the denitrification catalyst 4 and the NH3 decomposing catalyst 2, oxygen content at an inlet of the NH3 catalyst 2 becomes high. Therefore, NH3 decomposing performance of the NH3 decomposing catalyst 2 can be enhanced. As the NH3 decomposing catalyst 2, a catalyst consisting of a first constituent endowed with a reducing activity endowed by NH3 of NOx and a second constituent endowed with an activity of producing NOx from NH3 . |
