EXHAUST SMOKE DENITRATING APPARATUS AND METHOD OF EXHAUST SMOKE DENITRATION

摘要

An exhaust smoke denitrating apparatus in which using an NH₃ injection unit, compressed air is fed from blower to ejector for extracting of exhaust gas from HRSG1, and with thus obtained mixed gas, NH₃-containing gas is produced from NH₃ water by NH₃ water evaporator, the NH₃-containing gas injected through NH₃-containing gas injection nozzle of the HRSG1 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 NH₃ during the stage of evaporation of NH₃ 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 NH₃ water evaporation system can be carried out at an early stage. The temperature of NH₃-containing gas obtained by evaporation of NH₃ water can be lowered, and a lowering of thermal stress within NH₃-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 NH₃ water injection nozzle.