Thermochemical conversion of pulverized carbon carriers under super high heating rates and elevated pressures

Understanding the thermochemical conversion of pulverized carbon carriers under conditions mimicking blast furnace raceways is vital for improving efficiency and reducing emissions in high-temperature industrial processes. This study presents experimental investigations on the conversion behavior of three coal types—anthracitic, bituminous, and sub-bituminous—subjected to high heating rates (up to 106 K/s) and elevated pressures (2 bar(g)) using the novel Alternative Reducing Agent (ARA) reactor. The reactor enables particle conversion analysis under controlled entrained-flow conditions, simulating the intense thermal environment of blast furnaces.To isolate the effect of heating rate, experiments were conducted under three conditions: with hydrogen burner (high heating rate), without burner (low heating rate), and at matched outlet temperatures (to decouple heating rate from thermal exposure). Burnout ratios, ash content, and particle size distributions were assessed via the ash tracer method and laser diffraction analysis. Scanning Electron Microscopy (SEM) provided insights into morphological transformations.Results show that higher heating rates enhance coal reactivity, reduce char residue, and intensify pore formation, particularly in bituminous and sub-bituminous coals. The anthracitic coal displayed less pore development and ash flake deposition. Matching temperature conditions yielded intermediate burnout levels but significantly more residue than the high heating rate cases, confirming the heating rate’s impact on reactivity.The ARA reactor’s capability to simulate raceway conditions under controlled settings offers a valuable platform for further studies into rapid coal conversion and supports the development of more sustainable ironmaking technologies.