| abstract |
An exhaust smoke denitrating apparatus in which using an NH 3 injection unit, compressed air is fed from blower to ejector for extracting of exhaust gas from HRSG 1 , and with thus obtained mixed gas, NH 3 -containing gas is produced from NH 3 water by NH 3 water evaporator, the NH 3 -containing gas injected through NH 3 -containing gas injection nozzle of the HRSG 1 disposed on a front stream side of denitration catalyst layer. As any high-temperature exhaust gas is cooled and diluted by compressed air, there is no danger of oxidation of NH 3 during the stage of evaporation of NH 3 water. The moisture level of exhaust gas can be lowered, thereby enabling inhibition of any drain generation in exhaust gas extraction piping. Air warming within NH 3 water evaporation system can be carried out at an early stage. The temperature of NH 3 -containing gas obtained by evaporation of NH 3 water can be lowered, and a lowering of thermal stress within NH 3 -containing gas piping can be easily accomplished, so that denitration of exhaust gas can be easily accomplished. Even when sulfur oxides are contained in exhaust gas, it is feasible to avoid any problem of clogging of the NH 3 water injection nozzle. |