MAXIMUM INJECTION RATE OF PULVERIZED COAL INTO BLAST-FURNACE WITH CONSIDERATION OF UNBURNT CHAR

Experiments concerning the combustion and consumption of pulverized coal (PC) with high volatile matter content were conducted using an experimental apparatus capable of simulating the heat transfer and reaction in the lower part of the blast furnace. First. the calculating method of PC combustion efficiency in the raceway was proposed and the effects of blast conditions on the efficiency were investigated. Secondly, the calculating method of PC consumption efficiency at the apparatus top was proposed and the effects of blast conditions on the efficiency were investigated. Thirdly, the unburnt char weight accumulating in the apparatus was measured and the limited char weight not to cause the permeability deterioration in the apparatus was found. As a result of these analyses. the following conclusion was obtained concerning the maximum PC injection rate : Under the conditions of blast temperature of 1300-degrees-C, blast humidity of 5 X 10(-3) kg/Nm3 and oxygen enrichment of 2%. the limited PC injection rate is 245 X 10(-3) kg/Nm3 in the apparatus that prevents the discharge of char from the apparatus top, and the limited PC injection rate is 190 X 10(-3) kg/Nm3 that does not cause the permeability deterioration even when char accumulates in the apparatus.