METHOD FOR DECIDING VARIATION OF FURNACE HEAT IN BLAST FURNACE

PROBLEM TO BE SOLVED: To provide a deciding method of the variation of furnace heat in a blast furnace, by which the variation of the furnace heat in the blast furnace can simply and quickly be detected. SOLUTION: In the deciding method for deciding the variation of the furnace heat in the blast furnace by using process data in the blast furnace, the gas utilizing ratio and the ventilation at the lower part of the furnace are calculated and the variations with time of the gas utilizing ratios, the ventilations at the lower part of the furnace and the measured results of molten iron temperature in an iron tapping hole, are obtained and in the case the variating direction of these three characteristic values agrees with a prescribed combination, it is decided that the furnace heat is varied. Further, concerning the gas utilizing ratio, the ventilation at the lower part of the furnace and the molten iron temp. in the iron tapping hole, in the case all of these three characteristic values are varied at not lower than the setting value set based on a standard deviation of each value in a prescribed time, it is decided that the furnace heat is varied.