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Journal of Thermal Science

热科学学报

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2023 , Vol. 32 >Issue 1: 448 - 456

DOI: https://doi.org/10.1007/s11630-022-1737-z

燃烧和反应

Effect of Blending Ratio on the Sodium Release Behaviors, Ash Slagging Characteristics and Char Gasification Performances during Co-gasification of Zhundong Coal with Wuhai Coal

  • GUO Shuai ,
  • WANG Xiaofang
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  • Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China

网络出版日期: 2023-11-28

基金资助

This work was financially supported by National Natural Science Foundation of China (No. 22008236).

版权

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2022
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Effect of Blending Ratio on the Sodium Release Behaviors, Ash Slagging Characteristics and Char Gasification Performances during Co-gasification of Zhundong Coal with Wuhai Coal

  • GUO Shuai ,
  • WANG Xiaofang
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  • Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China

Online published: 2023-11-28

Supported by

This work was financially supported by National Natural Science Foundation of China (No. 22008236).

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2022
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摘要

在准东煤循环流化床气化时常遭遇一些灰相关问题，如炉膛底部结渣、换热器表面积灰等。较低的灰熔点和强烈的碱金属钠挥发是导致上述问题的罪魁祸首。在工程上，配煤是被认为提高灰熔点和控制钠挥发的可靠手段。在此项研究中，乌海煤被选用作为配煤煤种，配煤比例从0%到40%不等，间隔为10%。混合样品在实验室管式炉中950℃、水蒸气气氛下完成气化。分别采用ICP-OES、AFTs、XRD和TG等手段对一些重要指标如钠挥发量、灰熔融特性及气化特性进行分析。结果显示，配煤可以有效减少钠的挥发行为。对于灰结渣特性，可以惊奇地发现四个特征温度中的三个与配比呈现U型关系，这意味着低配比时可能引起更为严重的灰结渣问题，这归因于易熔融的含钠硅酸盐和硅铝酸盐比例显著增加。另外，配煤可以显著增加ST与DT差值，暗示床层抗温度波动能力显著增强。由于高含量的碱/碱土金属存在，在共气化时可以显著观察到协同作用。综合考虑上述多个重要指标，推荐乌海煤配比比例大约30%。

关键词： co-gasification; coal blending; ash slagging; sodium release

本文引用格式

GUO Shuai , WANG Xiaofang . Effect of Blending Ratio on the Sodium Release Behaviors, Ash Slagging Characteristics and Char Gasification Performances during Co-gasification of Zhundong Coal with Wuhai Coal[J]. 热科学学报, 2023 , 32(1) : 448 -456 . DOI: 10.1007/s11630-022-1737-z

Abstract

Some ash related problems, such as slagging at furnace bottom and fouling at the air pre-heater surface, are frequently encountered during circulating fluidized bed gasification (CFBG) of Zhundong coal. Low ash fusion temperatures (AFTs) and intense sodium release should be responsible for those problems. In industry, coal blending is deemed to be a feasible method to both improve AFTs and control sodium release. In this work, Wuhai coal was selected as blending coal. The ratio is varied from 0% to 40% by mass with 10% interval. The mixed samples were gasified by steam at 950°C in a lab-scale furnace. Some key indices, such as sodium release behaviors, ash slagging characteristics and char gasification performances, were investigated by ICP-OES, AFTs, XRD and TG analyzers, respectively. The results indicated that coal blending could significantly decrease sodium release behaviors. For ash slagging characteristics, it is surprised to find that three out of four AFTs (deformation temperature, softening temperature, hemispherical temperature) show an U-shaped correlation with blending ratio, indicating that a low ratio possibly causes more severe ash slagging problem. It is ascribed to the formation of substantial percentage of fusible Na-containing silicates and aluminosilicates. In addition, coal blending greatly increases ST-DT, implying that the ability of resistance to bed temperature fluctuation is markedly enhanced. Due to the high level of alkali and alkaline species, the synergistic effect is clearly observed during co-gasification. Taking all key indices into consideration, 30% blending ratio of Wuhai coal is recommended.

Key words： co-gasification; coal blending; ash slagging; sodium release

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