Numerical simulation of oxygen-enriched combustion in a precalciner using coal gangue-blended pulverized fuel

Abstract

This study emphasizes the potential role of coal gangue as an alternative fuel and oxygen-enriched combustion technology within TTF precalciners(Twin-Tank Furnace) in mitigating carbon emissions from cement production. The research primarily unfolds in two segments. Initially, the investigation addresses the influence of blending varying proportions of coal gangue under an air atmosphere on the internal temperature field and raw material decomposition components within the precalciner, aiming to discern the optimal blending ratio. Subsequently, the study simulates combustion under different oxygen-enriched atmospheres at the ideal coal-gangue blending ratio, establishing the combustion patterns under these conditions. Although the mixed fuel prompts symmetry in the flow field and temperature field, the distinct combustion characteristics of coal gangue and coal powder-following a 20% coal gangue blend-lead to an accelerated mainstream velocity and abbreviated fuel residence time. Consequently, the exit temperature and CO2 concentration diminish with increasing blending content, reaching an optimal raw material decomposition rate of 91.12% within the precalciner when blended with 20% coal gangue. Furthermore, in oxygen-enriched combustion, as the oxygen content escalates, both the average temperature at the precalciner's exit and the raw material decomposition rate witness an upsurge, whereas the average CO2 concentration at the outlet experiences a decline.