PROBLEM TO BE SOLVED: To provide a flue gas denitration device and a flue gas denitration method capable of eliminating a region where a denitration outlet NH3 concentration is locally high despite the magnitude of a load at a time of using a combustor, and suppressing the influence of NH3 on devices located downstream in a flue gas flow direction of a denitration catalyst.;SOLUTION: A flue gas denitration device 10 for removing NOx contained in flue gas by injecting NH3 into the flue gas generated in a coal fired boiler, includes: a denitration catalyst 13; a downstream measurement unit 15 measuring denitration outlet NOx concentrations at a plurality of locations downstream, in a direction of a flue gas flow, of the denitration catalyst 13 and in a plane with respect to the flue gas flow; and a flue gas circulation mechanism 20 vacuuming discharged flue gas flowing at a measurement point at which a locally low denitration outlet NOx concentration is measured among a plurality of measurement points by the downstream measurement unit 15, and neighborhoods of the measurement point to return the flow gas to upstream, in the direction of the flue gas flow, of the denitration catalyst 13.;COPYRIGHT: (C)2015,JPO&INPIT
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