Abstract Based on the bench-scale impinging entrained-flow gasifier with coal water slurry (CWS) as the feedstock and the development of advanced visualization techniques, the in-situ atomization and flame characteristics of CWS were investigated. A new imaging system was applied to capture the images around the burners in the operating condition. After image post-processing, the instantaneous flame, time-averaged flame and oscillation of the flame were discussed. With the statistical method, the droplet size distribution, oscillation of the droplet concentration and time-dependent droplet size were obtained to analyze the efficiency and stability of the atomization process. The instantaneous flame shows that the atomization and gasification process is turbulent. The time-average CWS flame shows that the atomization angle decreases with an increase in the ratio of elemental oxygen to elemental carbon (O/C ratio). The oscillation of the flame and the atomization process demonstrate that in-situ atomization is closely related to the CWS flame. The diameter and number of droplets after primary atomization decrease with the increase of the O/C ratio. The decreases in median diameter and unconsumed CWS rate demonstrate that the increase in O/C ratio improves the efficiency of the atomization process. The reduction in oscillation scopes of the droplet concentration and size demonstrates that the increase in O/C ratio improves the stability of the atomization process. In addition, the droplet concentration c in three different O/C conditions is 17.8 kg·m−3, 5.9 kg·m−3 and 1.6 kg·m−3 which demonstrates that the CWS is the dilute phase in the OMB gasifier.

中文翻译：

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撞击式气流床气化炉中水煤浆的原位雾化及火焰特性

摘要 以水煤浆（CWS）为原料的台架冲击夹带流气化炉和先进的可视化技术的发展，研究了水煤浆的原位雾化和火焰特性。应用新的成像系统来捕获运行条件下燃烧器周围的图像。经过图像后处理，讨论了瞬时火焰、时均火焰和火焰的振荡。用统计方法，得到雾化过程的雾化效率和稳定性，得到雾滴粒径分布、雾滴浓度波动和雾滴粒径随时间的变化规律。瞬时火焰表明雾化气化过程是湍流的。时均 CWS 火焰表明，随着元素氧与元素碳之比（O/C 比）的增加，雾化角减小。火焰的振荡和雾化过程表明原位雾化与水煤浆火焰密切相关。初级雾化后液滴的直径和数量随着 O/C 比的增加而减小。中值直径和未消耗 CWS 率的降低表明 O/C 比的增加提高了雾化过程的效率。液滴浓度和尺寸振荡幅度的减小表明O/C比的增加提高了雾化过程的稳定性。此外，三种不同O/C条件下的液滴浓度c分别为17.8 kg·m-3、5.9 kg·m-3和1。