DETECTION OF CHARGED MATERIAL LEVEL DURING EMPTYING AND BLOWING-OUT OPERATION OF BLAST FURNACE

PURPOSE:To detect the position of charged material levels, more particularly, the level arriving at the tuyere line and to make safe operations possible by estimating the position of the charged material level from the concn. of the O2 in a furnace observed at the end period of blowing-out when the reduction of the stock line has progressed. CONSTITUTION:While the compsns. of the gases in a blast furnace 1 are detected with a gas analyzer provided at the furnace top in the end period of blowing-out when the charging materials 2 in the furnace are down to near the level of tuyeres 10, whether these are within an explosion region or not is monitored. As the materials 2 turn from the state of concealing the tuyeres 10 to the state of exposing a part thereof, the gases in the furnace turn from CO to a mixture of CO and CO2 and if the blasting temp. is reduced at this time, there is possiblity of an explosion. In order to prevent this, the blasting temp. is reduced and the concn. of the O2 in the furnace is measured after it is confirmed that the compsn. of the gases in the furnace are out of the explosion region by the above-mentioned monitoring. If this unreacted O2 is not detected, the blasting temp. is returned to the original one, and when it is detected, it can be estimated that all the tuyeres are exposed. Therefore, the gases in the furnace are only the CO2 or unreacted O2 and if the blasting is stopped at this time, the explosion is averted.