Denitration apparatus used for a coal-fired boiler

摘要

The present invention provides a denitration apparatus that can reduce cost for additionally providing the denitration apparatus without deteriorating efficiency of a whole plant. A denitration apparatus according to the present invention includes: a coal-fired boiler (5); an economizer (1) provided to the coal-fired boiler (5); an upstream duct (7) that guides the exhaust gas from the upstream side of the economizer (1); a downstream duct (8) that guides the exhaust gas from the downstream side of the economizer (1); a first air preheater (2-1)provided at the downstream side of the upstream duct (7); a second air preheater (2-2) provided at the downstream side of the downstream duct (8); a denitration reactor (6) provided at the upstream side of the first air preheater (2-1) or the second air preheater (2-2); a first bypass duct (9-1) provided at the upstream side of the denitration reactor (6) for connecting the upstream duct (7) and the downstream duct (8); and a second bypass duct (9-2) provided at the downstream side of the denitration reactor (6) for connecting the upstream duct (7) and the downstream duct (8).