Kinetic study on co-combustion of pulverized anthracite and bituminite for blast furnace injection

Combustion behavior of single pulverized coals (PCs) and co-combustion characteristics of anthracite (AT) and bituminite (BT) blends with 20 wt.% volatile were studied by thermogravimetric experiments. The results indicated that reaction characteristics of PCs were closely related to their functional group structure and consequently, the pyrolysis of PCs with highly active functional groups initiated at lower temperatures. It was also noticed that the discrepancy of functional group structures between AT and BT might impair their interaction during combustion. The early exhaust of BT at low temperatures would possibly lead to an independent combustion of volatile and residual carbon and eventually the inefficient combustion of their blend. However, the mixing of AT and BT with similar functional group structures was more likely to achieve blends with superior combustion property. Simultaneously, non-isothermal kinetic analysis manifested that the combustion of blends followed random pore model (RPM), and therefore, the parameters calculated by RPM were more accurate to describe their combustion behavior. The kinetic calculation results showed that the activation energy required for decomposition of blends in early combustion stage was much lower owing to the excellent activity of volatile, while residual carbon with stable aromatic hydrocarbon demanded more energy to initiate its combustion.