Thermal reactivity and flowability of pulverized coal blending with iron-bearing dust injection in blast furnace process

Pulverized coal (PC) blending with iron-bearing dust (IBD) injection technology in blast furnace (BF) iron-making process was proposed to valorize the IBD. Three aspects containing the co-flow property of PC and IBD, thermal reactivity and corresponding kinetics during the PC combustion process, as well as thermal variation and unburned PC distribution in BF were the main focuses of the present work. It has found that the Carr-flowability indexes of PC and IBD appear little difference. Their blends can be smoothly transported when adding portion of the IBD is less than 6%. In addition, comprehensive combustibility index (S), ignition index (Ci), and burnout index (Db) of the PC are improved when the mass fraction of the IBD enhances from 0% to 3%, and 6%, which proves that blending with the IBD can accelerate the PC combustion process. Moreover, the combustion activation energy (E) decreases after adding the IBD, which supports the improved thermal reactivity. Also, the accumulation of unburned PC in BF presents a decline tendency, which may promote the permeability of BF and help enhancing the pulverized coal injection dosage.

Automated summary

Pulverized coal blending with iron-bearing dust injection technology in blast furnace iron-making process can effectively utilize the iron-bearing dust. This study focused on the co-flow property, thermal reactivity, and unburned coal distribution in the blast furnace. It was found that the blends of pulverized coal and iron-bearing dust can be smoothly transported and accelerate the combustion process. The addition of iron-bearing dust improved the comprehensive combustibility, ignition, and burnout of the coal. The combustion activation energy decreased after adding the iron-bearing dust, and the accumulation of unburned coal in the blast furnace decreased.