Transformation of alkali and alkaline earth metals in Zhundong coal during pyrolysis in an entrained flow bed reactor

Publication date: Available online 13 July 2019Source: Journal of Analytical and Applied PyrolysisAuthor(s): Dingcheng Liang, Qiang Xie, Zheng Wei, Chaoran Wan, Guangsheng Li, Junya CaoAbstractThe transformation of alkali and alkaline earth metals (AAEMs) in Zhundong coal during pyrolysis in an entrained flow bed reactor was elucidated, which provides theoretical guidance for selecting suitable processing technology for Zhundong coal. A typical coal was sampled, and a series of pyrolysis experiments with gradual and small increments in temperature was performed using an entrained flow bed reactor. Chars from pyrolysis at different temperatures were characterised using an improved sequential extraction method, inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), and field emission scanning electron microscopy coupled with energy dispersive spectroscopy (FESEM-EDS) to determine the occurrence modes, chemical composition, and the distribution of AAEMs on the surface of coal char as a function of the change in pyrolysis temperature. In addition, thermodynamic “FactSage” software was used to simulate the evolution of AAEM species during the entire pyrolysis process. Thus, a transformation mechanism of AAEMs in Zhundong coal during pyrolysis is proposed. The results show that as the pyrolysis temperature increases, the contents of water-soluble and exchangeable sodium in coal char decrease, and their release results in a decrease in total...
Source: Journal of Analytical and Applied Pyrolysis - Category: Chemistry Source Type: research