Babcock-hitachi Kabushiki Kaisha

Hitachi, Ltd.

Taro Sakata

Osamu Itou

Masayuki Taniguchi

Hirofumi Okazaki

Kenji Yamamoto

Yoshiki Noguchi

Shigehisa Sugita

Shigeyoshi Kawano

Kazuo Ikeuchi

Kenji Higashikawa

Masataka Ogasawara

Akio Nishiyama

Kimihiro Nonaka

Conventionally, a coarse mesh having a same size in that a calculation cell was used regardless to whether the location is near or remote from radiation elements such as calculation cells and wall face elements. Therefore, it took very long calculation time to calculate an energy exchange between a remote location covered by a coarse mesh and a noted cell. Further, there were many non-influential cells for calculation in a location remote from a noted radiation element for radiation calculation, the calculation accuracy was low. The present invention is to propose a method of calculating radiation which is provided with a measure for completing the calculation rapidly while keeping calculation accuracy high. In that, near at a calculation cell from which radiation energy is emitted or at a calculation cell P into which radiation energy is absorbed, a small (level) cell is used and at a remote location from the calculation cell P, a large (level n) cell formed by combining plural small cells is used. Further, a largest calculation cell which comes into field of view angle &#x394;&#x3a9; covered by a ray is selected. As a result, the accuracy of the radiation calculation is enhanced, the calculation time is shortened and amount of memory necessary for the calculation can be reduced.

Method of calculating radiation

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.

Pressurized fluidized bed boiler

A pressurized fluidized-bed boiler power plant comprises: a pressurized fluidized-bed boiler including a fluidized-bed boiler and a pressure vessel containing the fluidized bed; a single-shaft gas turbine including a gas turbine, an air compressor and an electric generator; and a steam turbine unit in which steam generated by the pressurized fluidized-bed boiler drives a turbine so that electricity is generated. In the power plant, an air cooler is situated on a duct for conveying the compressed air from the compressor to the boiler or at an inlet of the compressor. Alternatively, there may be provided a device for conveying the compressed air from the compressor by way of the air cooler to a space formed by the fluidized-bed boiler and the pressure vessel of the pressurized fluidized-bed boiler. During operation, the compressed air is cooled to a temperature level allowable for the pressure vessel before it is supplied to the boiler.

Pressurized fluidized-bed boiler power plant

Growing community of inventors

Yasuura, Japan

Taro Sakata