COREX预还原竖炉煤气析碳行为分析

COREX预还原竖炉还原煤气中CO浓度较高,竖炉内部较大温度范围都存在发生析碳反应的可能性。从竖炉操作压力和温度两个方面,分析了竖炉内不同区域内的析碳行为,同时重点分析了预还原竖炉内析碳反应对金属化率和下降管析碳量的影响。理论分析表明,析碳比例增加1%,竖炉金属化率平均降低3.4%;采用冷煤气作为冷却介质时,析碳量明显增加,此时不宜将下降管温度控制在750℃以下,且反窜煤气比例超过10%时,应及时切换成用N2冷却。

Carbon precipitation in gas during COREX shaft furnace operation

In COREX direction reduction shaft furnace process,CO concentration is higher and the carbon precipitation reaction occurs in large temperature range.The carbon precipitation behavior in different furnace areas is analyzed from the aspects of operation pressure and temperature.Meanwhile,the effect of carbon precipitation reaction on metallization rate and the amount of carbon precipitation in DRI downpipe is discussed.The theoretical analysis indicates that when the ratio of carbon precipitation is increased 1%,the metallization rate will be decreased averagely 3.4%;when the cold gas is used as cooling media,the amount of carbon precipitation will be obviously increased,the temperature of downpipe at the moment is not inadvisable to be controlled below 750℃;and when the rate of back fleeing gas is more than 10%,the cooling media should be switched over to N2 in time.