CIESC Journal ›› 2022, Vol. 73 ›› Issue (10): 4648-4658.DOI: 10.11949/0438-1157.20220770

• Energy and environmental engineering • Previous Articles     Next Articles

Effects of atmosphere and chemical composition on fusion characteristics of high-iron coal ash

Chong HE1(), Jin BAI2, Jing GUO3, Lingxue KONG2, Hao LU2, Huaizhu LI2, Yuhong QIN1, Wen LI2   

  1. 1.College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, Shanxi, China
    2.State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China
    3.College of Safety and Emergency Management Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
  • Received:2022-06-01 Revised:2022-07-22 Online:2022-11-02 Published:2022-10-05
  • Contact: Chong HE

气氛和化学组成对高铁煤灰熔融特性的影响机理

贺冲1(), 白进2, 郭晶3, 孔令学2, 鲁浩2, 李怀柱2, 秦育红1, 李文2   

  1. 1.太原理工大学环境科学与工程学院,山西 晋中 030600
    2.中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西 太原 030001
    3.太原理工大学安全与应急管理工程学院,山西 太原 030024
  • 通讯作者: 贺冲
  • 作者简介:贺冲(1989—),男,博士,讲师,hechong@tyut.edu.cn
  • 基金资助:
    国家自然科学基金项目(22108190)

Abstract:

Using ash melting point apparatus, XRD and thermodynamic simulation, the influence mechanism of atmosphere and chemical composition on the melting characteristics of high-speed iron coal ash was studied. The results indicate that the fusion temperature of high-iron coal ash decreases with the increasing iron content, or calcium content, or S/A (the mass ratio of SiO2 to Al2O3). Further, the fusion behavior of high calcium or high S/A and high-iron ash under mild reducing atmosphere (MR) follows the “melting-dissolution” mechanism due to the existence of the initial melting stage, while the fusion of low calcium or low S/A and high-iron ash under air belongs to the “softening-melting” mechanism. The iron accelerates the melting of quartz and anorthite under MR, and the calcium promotes the melting of quartz and corundum or transformations of these minerals to the calcium-based aluminosilicates. Under MR, the liquid content increases with the iron content or S/A, and the liquid viscosity decreases with the increasing calcium content or iron content, improving the mass transfer. In contrast, the crystallization of iron-containing solid solutions which were found in the low-calcium or low S/A and high iron ash leads to a higher liquid viscosity or lower liquid content under air, inhibiting the mass transfer of ash melting.

Key words: coal ash, gasification, fusion characteristic, crystallization, phase change, chemical composition, atmosphere

摘要:

采用灰熔点仪、XRD和热力学模拟,研究气氛和化学组成对高铁煤灰熔融特性的影响机理。研究结果表明,灰熔融温度随铁含量、钙含量或硅铝比增加而降低。弱还原气氛下低钙或低硅铝比煤灰熔融存在明显的初始熔融阶段,熔融过程遵循“软化-熔融”机理,而空气气氛下高钙或高硅铝比煤灰熔融过程属于“熔融-溶解”机理。弱还原气氛下铁含量增加显著促进石英和钙长石熔融,空气气氛下钙含量增加促进刚玉和石英熔融或转化为钙基硅铝盐。弱还原气氛下液相含量随硅铝比或铁含量增加而增加,液相黏度随钙含量或铁含量增加而降低,促进熔融传质;空气气氛下低钙或低硅铝比煤灰中铁存在于含铁固溶体,导致液相黏度高或液相含量低,熔融传质受阻。

关键词: 煤灰, 气化, 熔融特性, 结晶, 相变, 化学组成, 气氛

CLC Number: