Flash spray characteristics of a coal-liquid carbon dioxide slurry

Liquid carbon dioxide (LCO2) could potentially be utilized in coal gasification plants for effectively transporting coal particles, replacing conventional carriers such as water (H2O), particularly in wet-fed gasifiers. However, it is essential to understand the atomization behavior of LCO2 leaving an injector nozzle under both coal-free and coalfed conditions. We examined the atomization behavior of a coal-LCO2 slurry during the throttling process. The injector nozzle was mounted downstream of a high-pressure spray system. The effect of upstream pressure on flash atomization and devolatilization behavior was presented. Compared with the coal-LCO2 mixture, the spray pattern of the coal-water mixture was significantly different, since it evidenced a Rayleigh-type breakup mode. This difference indicates that the coal-water slurry did not transport the coal as effectively as the coal-LCO2 slurry.