Abstract:

The content of alkali metal sodium in Zhundong coal is high, and the fly ash generated during the gasification process leads to problems such as dust accumulation and corrosion in the heat exchanger, which poses a great challenge to the safe and stable operation of the gasifier. Ash fusion behavior is an important parameter to reveal the ash deposition behavior. In this study, oil shale (OS) as an additive with high contents of Si and Al was selected to investigate its effect on the ash fusion behavior of Zhundong high-sodium coal. The results showed that the initial sintering temperature and liquid phase sintering temperature section of Hongshaquan (HSQ) coal and Jiangerkuang (JEK) coal were increased with the increasing OS additions, which alleviate the deposition tendency of coal ash. Minerals analysis illustrated that the addition of OS decreased the anhydrite content and increased the quartz content in raw coal ashes. Meanwhile, sillimanite was formed, which increases the ash fusion temperatures (AFTs) of Zhundong high-sodium coal. For HSQ and JEK coal, when the OS addition was 15% and 20%, the ash deposition can be effectively avoided for the elevated AFTs. Finally, the prediction of deformation temperature and flow temperature was conducted based on artificial neural network and ash compositions.

Key words: Zhundong coal, oil shale, deposition, ash fusion behavior, mineral, neural network, fouling

摘要：

准东煤中碱金属钠的含量高，在气化过程中生成的飞灰导致换热器积灰、腐蚀等问题的发生，对气化炉的安全稳定运行带来极大的挑战。煤灰的熔融行为是阐明飞灰沉积行为的重要参数，选取含Si、Al较高的油页岩为添加剂，研究了油页岩添加对准东高钠煤灰熔融行为的影响及机理，探讨使用油页岩解决准东高钠煤气化利用中的飞灰沉积问题。结果表明，随着油页岩添加量的增加，准东高钠煤红沙泉和将二矿煤灰的初始烧结温度与液相烧结温度区间长度增加，煤灰的沉积倾向减轻；矿物质分析显示，油页岩的添加降低了初始煤灰中硫酸钙的含量，提高石英的含量，同时熔融过程中生成大量夕线石，是准东高钠煤灰熔点升高的主要原因。对于红沙泉与将二矿煤，分别添加15%和20%的油页岩可有效提高煤灰的熔融特征温度，避免在气化过程中飞灰发生沉积。最后，基于神经网络模型，建立了准东高钠煤添加油页岩后的煤灰变形温度(DT)及流动温度(FT)的预测模型。

关键词: 准东煤, 油页岩, 沉积物, 煤灰熔融行为, 矿物质, 神经网络, 结垢