Babcock-hitachi Kabushiki Kaisha

Kenji Higashikawa

Taro Sakata

Masataka Ogasawara

Kimihiro Nonaka

Akio Nishiyama

In a pressurized fluidized bed boiler, furnace means is divided into at least two separate furnaces: a furnace with an evaporator and a superheater disposed therethrough, and a furnace with the superheater and a reheater disposed therethrough. The furnaces are accommodated in separate pressure vessels, respectively. Air is supplied into the pressure vessels through air pipes connected to the pressure vessels, where it is used for pressurizing the pressure vessels, and then supplied into the furnaces through their lower portions, where it is used as a combustion air. An oxygen concentration meter is mounted in an exhaust gas pipe in an outlet of the furnace, and an air flow rate adjusting valve 3 is mounted outside each of the pressure vessels. Thus, a more precise control of air-fuel ratio can be performed independently for every furnaces by controlling the air flow rate adjusting valves on the basis of at least one of an oxygen concentration signal from the oxygen concentration meter and a fuel supply amount signal from a fuel supply pump motor.

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Kure, Japan

Kenji Higashikawa