Abstract In this study, the characterization of the fly and bottom ashes from an industrial gasification plant for biomass syngas production were investigated and compared in terms of particle size distribution, chemical composition, fusibility, mineralogy and morphology. The experimental results indicated that the characteristic particle sizes of the bottom ashes from gasifier were larger than those of the fly ashes from cyclone or sprayer. By contrast, the fly ashes contained higher contents of potassium, sulphur and chlorine. The base-to-acid ratio (Rb/a) values for those fine fractions in the bottom residues and the fly particles from cyclone were in high deposition range (Rb/a > 1.0) while that for the slags in the bottom ash or the fly particles from sprayer was in medium deposition range (0.5–1.0). As regards the fouling index (Fu), the value of cyclone ash (Fu = 41.2) was higher than those of the other ashes, reflecting its relatively higher deposition tendency on heat transfer surfaces. Besides, the fusion temperatures of the fly ashes were lower than those of bottom ashes. The rounded forms of fly particles could be regarded as the indicative of ash melting. Comparison of thermograms indicated that the bottom ash contained more organics than fly ash, thus explaining its relatively higher weight loss during ash fusion. In practice, more attention should be paid on the rational control of operating temperature, which could relieve the occurrence of ash deposition/agglomeration to some extent.

中文翻译：

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工业规模气化厂农残气化过程中底灰和飞灰的表征比较——实验与分析

摘要 在本研究中，研究了用于生物质合成气生产的工业气化装置的飞灰和底灰的粒度分布、化学成分、可熔性、矿物学和形态学的表征和比较。实验结果表明，气化炉底灰的特征粒径大于旋风或喷雾器底灰的特征粒径。相比之下，飞灰的钾、硫和氯含量更高。底渣中细小部分和旋风分离器飞粉颗粒的碱酸比 (Rb/a) 值处于高沉积范围 (Rb/a > 1.0)，而底灰中的炉渣或来自旋风分离器的飞粉颗粒的碱酸比 (Rb/a) 值处于高沉积范围内 (Rb/a > 1.0)。来自喷雾器的苍蝇颗粒处于中等沉积范围（0.5-1.0）。关于结垢指数（Fu），旋风灰分值（Fu=41.2）高于其他灰分，反映其在传热面上的沉积倾向相对较高。此外，飞灰的熔化温度低于底灰。飞粉颗粒的圆形可被视为灰分熔化的标志。热谱图的比较表明，底灰比飞灰含有更多的有机物，从而解释了其在灰融合过程中相对较高的重量损失。在实践中，应更加注意操作温度的合理控制，这可以在一定程度上缓解积灰/结块的发生。飞灰的熔化温度低于底灰。飞粉颗粒的圆形可被视为灰分熔化的标志。热谱图的比较表明，底灰比飞灰含有更多的有机物，从而解释了其在灰融合过程中相对较高的重量损失。在实践中，应更加注意操作温度的合理控制，这可以在一定程度上缓解积灰/结块的发生。飞灰的熔化温度低于底灰。飞粉颗粒的圆形可被视为灰分熔化的标志。热谱图的比较表明，底灰比飞灰含有更多的有机物，从而解释了其在灰融合过程中相对较高的重量损失。在实践中，应更加注意操作温度的合理控制，这可以在一定程度上缓解积灰/结块的发生。