Kabushiki Kaisha Toshiba

Toshiba Engineering Co.

Toshie Kataoka

Haruo Oguchi

Shirou Hino

A power generation plant possessing a gas turbine includes a nitrogen oxide removal apparatus for injecting a reducing material such as ammonia into exhaust gas from the gas turbine to reduce NOx emission under a predetermined level. To a feedback control system for estimating such an amount of the reducing material to be injected that a measured NOx amount at an outlet of the nitrogen oxide removal apparatus will get toward a NOx setpoint there is added a feedback control system for estimating an injection amount of the reducing material required for a NOx flow rate at an inlet of the nitrogen oxide removal apparatus based upon a mole ratio of the reducing material to the NOx. The measured NOx at the inlet of the nitrogen oxide removal apparatus is corrected based upon the combustion conditions of the gas turbine unit. NOx setpoint and the mole ratio are estimated based upon the operating conditions of a plant related to nitrogen oxide removal efficiency. Even in the plant state where variations of NOx production are severe, NOx and the reducing material exhausted into the atmosphere are maintained at an acceptable level.

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Kawasaki, Japan

Toshie Kataoka