METHOD FOR CONTROLLING TEMPERATURE AT FURNACE BOTTOM IN BLAST FURNACE

PURPOSE:To quickly control local raising of temp. at furnace bottom while preventing operational trouble in a blast furnace by controlling the supplying rate of a Ti source according to variance of difference of blasting rates for tuyeres between tyeres subjected blasting and no blasting of the Ti source in the method of blasting the Ti source. CONSTITUTION:When the detected temp. at the furnace bottom in the blast furnace 1 exceeds a set value, the powdery Ti source is blown from plural pieces of tuyeres by using blast source 7 and Ti source supplying device 6 to maintain the furnace bottom temp. to the normal value. Now, at the time of detecting the temp. exceeding the set value from a temp. detecting meter, by opening the corresponding pressure control value 9, supplying of the Ti source from some tuyere 3 is started. The blasting values detected with a flow meter 10 of the blast branching pipe 4, which supplies the Ti source, and of the other blast branching pipe which does not supply the Ti source, are continuously inputted to a computer 11. The difference of average flow rates between the former and the latter is calculated and opening degree of the pressure control valve 9 is made to small or larger according to the value of difference of positive or negative, and when the above difference approaches near zero, the opening degree is kept.