Evaluation of oxygen partial pressure, absolute pressure, and heating rate effects on the thermochemical conversion of a low volatile coal

Knowledge of the thermochemical conversion behavior of pulverized coal (PC) in the raceway zone of a blast furnace helps improve process efficiency. Determining the kinetic parameters of PC under process conditions is difficult, as direct measurements are limited. The Alternative Reducing Agents (ARA) reactor is capable of reproducing the reaction conditions and was used to investigate the reactivity of a low volatile coal. Multiple experiments under different operational conditions were carried out to isolate the effects of oxygen partial pressure, absolute pressure, temperature, and heating rate. The high heating rate is provided by a hydrogen burner at the particle injection point, increasing the particle heating rate by a factor of 2 to 4. The results of the pyrolysis experiments demonstrate that higher pressure inhibits the pyrolysis and show no significant influence of temperature for experiments above 1200 °C. The activation of the burner did not increase the burnout of the pyrolysis experiments. The combustion experiments showed an increasing burnout with higher oxygen partial pressure and lower absolute pressure. The operational temperature did not significantly change the oxygen reaction order in the experiments without the burner. The burner activation increased burnout by increasing the heating rate and gas temperature.