Liquid carbon dioxide-assisted (LCO 2 -assisted) atomization can be used in coal-water slurry gasification plants to prevent the agglomeration of coal particles. It is essential to understand the atomization behavior of the water-LCO 2 mixture leaving the injector nozzle under various conditions, including the CO 2 blending ratio, injection pressure, and chamber pressure. In this study, the flash-atomization behavior of a water-LCO 2 mixture was evaluated with regard to the spray angle and penetration length during a throttling process. The injector nozzle was mounted downstream of a high-pressure spray-visualization system. Based on the results, the optimal condition for the effective transport of coal particles was proposed.

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This work presents primary results of a parameter study for entrained flow gasification using a steady-flow reactor model. The influences of important parameters such as coal types, gasifier pressure, gas/coal feeding rate, and coal particle size were studied based on coal conversion and gas product species. The prediction results were compared and validated against those published previously. In particular, a relative importance of reaction stoichiometry, temperature, reaction time (kinetics), or residence time considered in this simulation work was evaluated to affect the gas composition produced from different coals. The optimal carbon monoxide concentration was observed at an oxygen-to-fuel ratio of 0.8, while a greatest carbon conversion was found at a steam-to-fuel ratio of 0.4. Coal particle size has a strong influence on carbon conversion. However, the coal feeding rate has no effect on carbon conversion despite differences in residence time.