Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags

doi:10.1016/j.cjche.2022.03.003

中国化学工程学报 ›› 2023, Vol. 53 ›› Issue (1): 1-13.DOI: 10.1016/j.cjche.2022.03.003

• Full Length Article • 下一篇

Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags

Meng Li¹, Jianliang Xu¹, Huixia Xiao¹, Xia Liu¹, Guangsuo Yu^1,2, Xueli Chen¹

1. Institute of Clean Coal Technology, East China University of Science and Technology, Shanghai 200237, China;
2. State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, China

收稿日期:2021-10-03 修回日期:2022-03-09 出版日期:2023-01-28 发布日期:2023-04-08
通讯作者: Jianliang Xu,E-mail:xujl@ecust.edu.cn;Xueli Chen,E-mail:cxl@ecust.edu.cn
基金资助:
This research was financially supported by the National Natural Science Foundation of China (21878082).

Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags

Meng Li¹, Jianliang Xu¹, Huixia Xiao¹, Xia Liu¹, Guangsuo Yu^1,2, Xueli Chen¹

1. Institute of Clean Coal Technology, East China University of Science and Technology, Shanghai 200237, China;
2. State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, China

Received:2021-10-03 Revised:2022-03-09 Online:2023-01-28 Published:2023-04-08
Contact: Jianliang Xu,E-mail:xujl@ecust.edu.cn;Xueli Chen,E-mail:cxl@ecust.edu.cn
Supported by:
This research was financially supported by the National Natural Science Foundation of China (21878082).

摘要/Abstract

摘要： The crystallization has significant influence on fluidity of slag and slag discharge of entrained-flow-bed (EFB) gasifier. The crystallization characteristics and fluidity of five synthetic slags with different MgO/CaO ratios prepared on the basis of the range of oxide contents of Zhundong coal ash were investigated in this study. The results show that with the MgO/CaO ratio increase, the initial crystallization temperature increases, and the main temperature range of crystallization ratio growth moves to higher temperature range gradually which causes T_p25 (T_p25 is the temperature corresponding to the viscosity of 25 Pa·s) to increase. Mg-rich crystals are formed preferentially than Ca-rich crystals when adding the same amount of MgO and CaO during cooling. The effective slagging operating temperature range decrease from 217 ℃ for the slag with a 0:4 MgO/CaO ratio to 44 ℃ for the slag with a 4:0 MgO/CaO ratio with the MgO/CaO ratio increase. The slags with 2:2 and 1:3 MgO/CaO ratios show similar effective slagging operating temperature range, T_p25 and the temperature corresponding to the viscosity of 2 Pa·s. However, compared with the slag with a 1:3 MgO/CaO ratio, the crystallization ratio and rate of slag with a 2:2 MgO/CaO ratio are lower within lower temperature range (1300–1200 ℃), causing its lower critical viscosity temperature and wider actual operating temperature range. Of the five slags, the widest effective slagging operating temperature range and the lowest T_p25 of the slag with a 0:4 MgO/CaO ratio due to its low crystallization ratio, and wider actual operating temperature range of the slag with a 2:2 MgO/CaO ratio make the two slags suitable for slag discharge of EFB gasifier.

关键词: Crystallization characteristics, Fluidity, Slags, MgO/CaO

Abstract: The crystallization has significant influence on fluidity of slag and slag discharge of entrained-flow-bed (EFB) gasifier. The crystallization characteristics and fluidity of five synthetic slags with different MgO/CaO ratios prepared on the basis of the range of oxide contents of Zhundong coal ash were investigated in this study. The results show that with the MgO/CaO ratio increase, the initial crystallization temperature increases, and the main temperature range of crystallization ratio growth moves to higher temperature range gradually which causes T_p25 (T_p25 is the temperature corresponding to the viscosity of 25 Pa·s) to increase. Mg-rich crystals are formed preferentially than Ca-rich crystals when adding the same amount of MgO and CaO during cooling. The effective slagging operating temperature range decrease from 217 ℃ for the slag with a 0:4 MgO/CaO ratio to 44 ℃ for the slag with a 4:0 MgO/CaO ratio with the MgO/CaO ratio increase. The slags with 2:2 and 1:3 MgO/CaO ratios show similar effective slagging operating temperature range, T_p25 and the temperature corresponding to the viscosity of 2 Pa·s. However, compared with the slag with a 1:3 MgO/CaO ratio, the crystallization ratio and rate of slag with a 2:2 MgO/CaO ratio are lower within lower temperature range (1300–1200 ℃), causing its lower critical viscosity temperature and wider actual operating temperature range. Of the five slags, the widest effective slagging operating temperature range and the lowest T_p25 of the slag with a 0:4 MgO/CaO ratio due to its low crystallization ratio, and wider actual operating temperature range of the slag with a 2:2 MgO/CaO ratio make the two slags suitable for slag discharge of EFB gasifier.

Key words: Crystallization characteristics, Fluidity, Slags, MgO/CaO

Meng Li, Jianliang Xu, Huixia Xiao, Xia Liu, Guangsuo Yu, Xueli Chen. Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags[J]. 中国化学工程学报, 2023, 53(1): 1-13.

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Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags

Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags

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