METHOD FOR PREVENTING DETERIORATION OF AIR PERMEABILITY OF BLAST FURNACE BY REDUCING INJECTION QUANTITY OF PULVERIZED COAL IN PROPORTION TO REDUCED AMOUNT OF BLAST BLOWN INTO BLAST FURNACE

摘要

PURPOSE: To provide a method for controlling an injection quantity of pulverized coal according to reduction of an amount of blast blown into blast furnace, the method for preventing deterioration of combustion capacity by interlockingly controlling a set injection quantity value according to reduction of the blast amount when an amount of blast blown into the blast furnace is reduced by the abnormal operation state. CONSTITUTION: The method comprises a step of setting a blast reduction control section of which upper limit is a normal amount of blast supplied during normal blast furnace operation, and of which lower limit is a blast amount at a time point when a static blast amount control for ensuring weight of charging material is converted into a static blast pressure control during reduced blast operation of the blast furnace; a step of uniformly dividing the set blast reduction control section in a distance corresponding to a certain percentage of the normal blast amount; a step of designating a pulverized coal injection set value to prepare for reduction of blast amount by uniformly dividing a space between the maximum pulverized coal injection set value and the minimum pulverized coal injection set value as many as the number of the blast reduction control sections after taking the maximum quantity of pulverized coal combustible without enriched oxygen as a maximum pulverized coal injection set value corresponding to an upper limit point of the blast reduction control sections and taking 50% of the maximum pulverized coal injection set value as a minimum pulverized coal injection quantity set value at a lower limit point of the blast reduction control sections; a step of checking whether abnormal blast reduction is instructed in blast furnace operation or not; and a step of controlling injection of pulverized coal by a pulverized coal injection quantity set value corresponding to a blast amount checked in the set blast reduction control section by checking a blast amount of the blast furnace if the abnormal blast reduction is instructed as a result of the check.