SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2021, Vol. 35 ›› Issue (7): 239-246.DOI: 10.1016/j.cjche.2020.08.033

• Energy Science and Technology • 上一篇    下一篇

Modification of ash flow properties of coal rich in calcium and iron by coal gangue addition

Huaizhu Li1,2, Lingxue Kong2, Jin Bai2, Zongqing Bai2, Zhenxing Guo2, Wen Li2   

  1. 1. Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education, Xuzhou 221116, China;
    2. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
  • 收稿日期:2020-07-10 修回日期:2020-08-14 出版日期:2021-07-28 发布日期:2021-09-30
  • 通讯作者: Lingxue Kong, Jin Bai
  • 基金资助:
    This work was supported by the Fundamental Research Funds for the Central Universities (2017CXNL04).

Modification of ash flow properties of coal rich in calcium and iron by coal gangue addition

Huaizhu Li1,2, Lingxue Kong2, Jin Bai2, Zongqing Bai2, Zhenxing Guo2, Wen Li2   

  1. 1. Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education, Xuzhou 221116, China;
    2. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
  • Received:2020-07-10 Revised:2020-08-14 Online:2021-07-28 Published:2021-09-30
  • Contact: Lingxue Kong, Jin Bai
  • Supported by:
    This work was supported by the Fundamental Research Funds for the Central Universities (2017CXNL04).

摘要: Flow property of coal ash and slag is an important parameter for slag tapping of entrained flow gasifier. The viscosity of slag with high contents of calcium and iron exhibits the behavior of a crystalline slag, of which viscosity sharply increases when temperature is lowered than temperature of critical viscosity (TCV). The fluctuation in temperature near the TCV can cause an accumulation of slag inside the gasifier. In order to prevent slag blockage, it is necessary to adjust the ash composition by additive to modify the flow property of coal rich in calcium and iron. Main components of coal gangue are Al2O3 and SiO2, which is a potential additive to modify the ash flow properties of these coals. In this work, we investigated the ash flow properties of a typical coal rich in calcium and iron by adding coal gangue with different SiO2/Al2O3 ratio. The results showed that the ash fusion temperatures (AFTs) firstly decreased, and then increased with increasing amount of coal gangue addition. Chemical composition of coal ash rich in calcium and iron moved from gehlenite primary phase to anorthite, quartz and corundum primary phases. The slags with coal gangue addition behaved as a glassy slag, of which the viscosity gradually increased as temperature decreased. Besides, a high SiO2/Al2O3 ratio of coal gangue was beneficial to modify the slag viscosity behavior. Addition of coal gangue with a high SiO2/Al2O3 ratio impeded formation of crystalline phases during cooling. This work demonstrated that coal gangue addition was an effective way to improve the ash flow properties of the coal rich in calcium and iron for the entrained flow gasifier.

关键词: Coal gangue, Coal rich in calcium and iron, Ash fusion temperatures, Viscosity-temperature characteristic, Phase transformation

Abstract: Flow property of coal ash and slag is an important parameter for slag tapping of entrained flow gasifier. The viscosity of slag with high contents of calcium and iron exhibits the behavior of a crystalline slag, of which viscosity sharply increases when temperature is lowered than temperature of critical viscosity (TCV). The fluctuation in temperature near the TCV can cause an accumulation of slag inside the gasifier. In order to prevent slag blockage, it is necessary to adjust the ash composition by additive to modify the flow property of coal rich in calcium and iron. Main components of coal gangue are Al2O3 and SiO2, which is a potential additive to modify the ash flow properties of these coals. In this work, we investigated the ash flow properties of a typical coal rich in calcium and iron by adding coal gangue with different SiO2/Al2O3 ratio. The results showed that the ash fusion temperatures (AFTs) firstly decreased, and then increased with increasing amount of coal gangue addition. Chemical composition of coal ash rich in calcium and iron moved from gehlenite primary phase to anorthite, quartz and corundum primary phases. The slags with coal gangue addition behaved as a glassy slag, of which the viscosity gradually increased as temperature decreased. Besides, a high SiO2/Al2O3 ratio of coal gangue was beneficial to modify the slag viscosity behavior. Addition of coal gangue with a high SiO2/Al2O3 ratio impeded formation of crystalline phases during cooling. This work demonstrated that coal gangue addition was an effective way to improve the ash flow properties of the coal rich in calcium and iron for the entrained flow gasifier.

Key words: Coal gangue, Coal rich in calcium and iron, Ash fusion temperatures, Viscosity-temperature characteristic, Phase transformation