高炉内H2体积分数对焦炭气化反应的影响

 为了明确高炉富氢冶炼条件下焦炭的气化行为,利用高温模拟试验研究了高炉内φ(H₂)对焦炭气化反应和孔隙结构的影响,得到了不同φ(H₂)下矿石的还原与焦炭气化反应的关系、焦炭气化最严重的温度区间及焦炭微观孔隙结构的变化。研究结果表明,矿石的还原度和焦炭的失重率在升温过程中都逐渐增加。随着φ(H₂)的增加,焦炭的气化率增加幅度最大的温度区间逐渐向低温区移动,主要由于随着φ(H₂)的增加,矿石的还原反应逐渐趋向于在低温区进行,使得其在高温区产生的可供焦炭气化反应的CO₂和H₂O的总量降低;φ(H₂)由5%增加至10%时,焦炭的气化率增加幅度最大;随着φ(H₂)的增加,焦炭的平均壁厚逐渐降低,孔隙率、比表面积及总孔容都逐渐增加;焦炭大孔所占比例逐渐增加,焦炭气孔壁的薄壁结构所占比例逐渐增加。

Effect of H2 volume percent on gasification reaction of coke in blast furnace

In order to clarify the gasification behavior of coke under the condition of hydrogen-rich smelting in the blast furnace,the effect of φ(H₂) on gasification reaction and pore structure of coke were studied by high temperature simulation experiment. The relationships between ore reduction and coke gasification reaction under different φ(H₂),the most serious temperature range of coke gasification and the change of coke micro pore structure were obtained. The results show that the reduction degree of iron ore and the weight loss rate of coke increase gradually during the heating process. The temperature at which the weight loss rate of coke increases the most decreases with increasing φ(H₂). The main reason is that with the increase of φ(H₂),the reduction of ore tends to be carried out in the low-temperature zone,which makes the total amount of CO₂ and H₂O produced in the high-temperature zone for coke gasification reduce. When the φ(H₂) increases from 5% to 10%,the weight loss rate of coke increases the most. With an increasing φ(H₂) in the gas,the average wall thickness of the coke decreases gradually,the porosity,specific surface area and total pore volume increase gradually,the proportion of large pores increases,the proportion of thin-walled structures increases.