Combustion performance of pulverized coal and corresponding kinetics study after adding the additives of Fe₂O₃ and CaO

Abstract

Combustion performance of pulverized coal (PC) in blast furnace (BF) process is regarded as a criteria parameter to assess the proper injection dosage of PC. In this paper, effects of two kinds of additives, Fe₂O₃ and CaO, on PC combustion were studied using the thermogravimetric method. The results demonstrate that both the Fe₂O₃ and CaO can promote combustion performance index of PC including ignition index (C _i), burnout index (D _b), as well as comprehensive combustibility index (S _n). The S _n increases from 1.37 × 10⁻⁶ to 2.16 × 10⁻⁶ %²·min⁻²·°C⁻³ as the Fe₂O₃ proportion increases from 0 to 5.0wt%. Additionally, the combustion kinetics of PC was clarified using the Coats-Redfern method. The results show that the activation energy (E) of PC combustion decreases after adding the above additives. For instance, the E decreases from 56.54 to 35.75 kJ/mol when the Fe₂O₃ proportion increases from 0 to 5.0wt%, which supports the improved combustion performance. Moreover, it is uneconomic to utilize pure Fe₂O₃ and CaO in production. Based on economy analysis, we selected the iron-bearing dust (IBD) which contains much Fe₂O₃ and CaO component to investigate, and got the same effects. Therefore, the IBD is a potential option for catalytic PC combustion in BF process.

Keywords

pulverized coal / combustion performance / blast furnace / kinetics / additives

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