Exhaust heat recovery boiler

摘要

An exhaust heat recovery boiler in which an exhaust gas discharged from a gas turbine into a boiler duct to recover a heat of the exhaust gas and ammonia is injected to and mixed with the exhaust gas to reduce nitrogen oxide contained in the exhaust gas, the exhaust heat recovery boiler comprising: a boiler duct of a horizontal installation type having an inner hollow portion along which an exhaust gas flows from an upstream side to a downstream side; a superheater; an evaporator; a denitration reactor; and an economizer, which are disposed inside the boiler duct in this order from the upstream side to the downstream side of the exhaust gas flow therein. A drum is disposed outside the boiler duct and connected to the evaporator and a downcomer pipe extending from the drum into the boiler duct. An ammonia injection unit is disposed inside the boiler duct for injecting ammonia, and the ammonia injection unit is disposed upstream side of the evaporator closely to the downcomer pipe unit on either one of upstream side and downstream side of the downcomer pipe unit. <IMAGE>