PURPOSE: To restrict the variations of reheated steam temperature by providing a dynamic characteristic model of on-line operation into which a fuel amount and an air ratio to each burner are successively inputted, and adjusting the burner air ratio when a deviation between an actually measured value and a calculated value on the basis of the model is excessive.
CONSTITUTION: A dynamic characteristic model 40 obtains a calculated value 51 of fire furnace outlet gas temperature based upon the analysis of combustion in a fire furnace and of radiation on the basis of a synthesized signal 58 of a fine powdered coal amount estimation signal 69 of each burner at that time, a previously supposed fuel ratio, and fire furnace contamination conditions. A fuel ratio estimator 43 concludes the previously supposed signal 48 is overestimated and reduces it with the aid of an optimum coefficient estimated by the technique of an expanded Karman filter provided a calculated value 49 of steam temperature at a water wall outlet is smaller than an actually measured signal 47. Further, the fuel estimator 43 increases the signal 48 provided the relationship between the calculated value 49 and the actually measured value signal 47 is opposite to the above description, and finally converges the signal 48 to a true value. An air ratio instruction evaluator 44 evaluates an air ratio instruction signal 56 of each burner based upon the signal 48.
TSUMURA SHUNICHI
YAMAMOTO KOJI
KAWASE TAKAYO
SHIMODAIRA KATSUMI
