Hitachi, Ltd.

Atsushi Yokogawa

Nobuo Kurihara

Yoshio Sato

Atsumi Watanabe

Mitsuyo Nishikawa

Hisanori Miyagaki

Toshihiko Higashi

Yoshihiro Shimada

Yasuo Morooka

A combustion control method wherein manipulated variables or the amounts of fuel and air in at least one combustion zone of a boiler are regulated so that both the amount of nitrogen oxides and the amount of unburned coal in the ash at an outlet of a burner furnace or at least one of them passes the regulation standards and satisfies the requirements for operating a plant. The method is characterized by varying the amounts of fuel and air in performing trial operations on manipulated variables to evaluate the nitrogen oxides at the furnace outlet, the unburned coal in the ash at the furnace outlet and the stability of combustion, and declaring as optimum manipulated variables those amounts of fuel and air used for performing the trial operations which achieve results such that the combustion is found to be stabilized, at least the nitrogen oxides at the furnace outlet satisfy the requirement and the thermal efficiency of the boiler is judged to be at the highest level by a boiler thermal efficiency judging section.

Combustion control method

This invention relates to the supervision of a combustion state of a combustion furnace. A flame formed concentrically with the direction of a fuel jetted from a burner being the center is measured from its side, and two oxidizing flame zones as high luminance zones are extracted. Using the shape parameters of the flame, an index for reducing NOx and unburnt components in ash are calculated and estimated so as to supervise the combustion state. The positions or centroids of the flames and the distance between the centroids are used as the shape parameters, and the flame shape is divided into two zones for easy display of each zone.

Method and apparatus for supervising combustion state

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Hitachi, Japan

Atsushi Yokogawa