焦炭反应性对高炉块状带含铁炉料还原的影响

研究了五种具有不同反应性的焦炭对高炉块状带含铁炉料还原的影响规律,并对料层的压差、CO体积分数以及含铁炉料的还原程度进行了分析.当炉内通入的原始气体中CO体积分数(仅考虑CO和CO₂)为72.22%时,随着焦炭反应性的增强,焦炭气化速率加快,含铁炉料颗粒周围的CO体积分数升高,含铁炉料的还原度依次增高,还原度从使用低活性焦炭时的33.18%增大到使用高活性焦炭时的53.83%;而当原始气体成分中CO体积分数为66.67%时(低于900℃还原FeO的平衡气相体积分数),使用高反应性焦炭也可还原出金属铁.由此可见,适当增加入炉焦炭的反应性,可促进焦炭与含铁炉料间的耦合反应,提升料层CO体积分数,提高含铁炉料进入软熔带区域的金属化率.

Influence of coke reactivity on the ferric burden reduction of the lumpy zone in a blast furnace

The influence of coke reactivity on the ferric burden reduction of the lumpy zone in a blast furnace was studied by using five kinds of coke with different reactivities.The pressure drop and CO volume fraction of the burden layer as well as the burden reduction degree were also analyzed.It is found that the coke gasification rate,CO volume fraction of the burden surface,and burden reduction degree increase with the increase of coke reactivity.When the CO volume fraction(only considering CO and CO₂) of the original gas is 72.22%the burden reduction degree increases from 33.18%for low-reactivity coke to 53.83%for high-reactivity coke.When the CO volume fraction of the original gas is 66.67%,which is slightly lower than the CO theoretical equilibrium volume fraction of FeO reduction at 900℃, metallic iron can be obtained by means of high-reactivity coke.Therefore,appropriately increasing the coke reactivity in a blast furnace can promote the coupling reaction between coke and ferric burden,improve the CO volume fraction of the burden layer,and increase the burden metallization rate before going into the cohesive zone.