Effect of Quenching Temperatures on Melting Characteristics of Coal Ash in a Reducing Atmosphere

详细信息    查看全文

• 作者：Haigang Wang ; Penghua Qiu ; Yaoqiang Li ; Zongjie Han ; Shijun Wu ; Gangbo Zhao
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：April 19, 2012
• 年：2012
• 卷：26
• 期：4
• 页码：2204-2219
• 全文大小：1498K
• 年卷期：v.26,no.4(April 19, 2012)
• ISSN：1520-5029

文摘

Two representative Chinese bituminous coals (one with rich Ca content, having a low melting temperature, and the other with rich Fe content, having a high melting temperature) were selected for this study to investigate the effect of quenching temperatures on melting characteristics of coal ash in a reducing atmosphere (6:4 CO/CO₂). The final structures were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray (SEM鈥揈DX), and differential thermal analysis (DTA). The results show that, with the quenching temperature increasing, the crystalline volume percentage experiences a maximum value. However, the thermal properties (the glass transition temperature and the melting temperature) determine the maximum crystalline volume percentage temperature. There is a large variation in the phase compositions with an increase of the quenching temperatures, but the maximum diffraction peak intensities of most minerals simultaneously occur. A comparison of the coal ash samples after quench and direct heat treatment shows that there is a low crystalline volume percentage and simple phase compositions for the quenching process at corresponding temperatures, which are due to a preheat treatment at high temperatures prior to quench. Anorthite can form a better crystal shape in the coal ash sample with a low melting temperature and high Ca content for the quenching process. The diffusion controls the dissolution of the Fe鈥揙 particle, especially for the high melting temperature coal ash with a high Fe content.