Effect of Key Minerals on the Ash Melting Behavior in a Reducing Atmosphere

详细信息    查看全文

• 作者：Haigang Wang ; Penghua Qiu ; Xu Shi ; Jifeng Zhang ; Yuqing Chen ; Shaohua Wu
• 刊名：Energy & Fuels
• 出版年：2011
• 出版时间：August 18, 2011
• 年：2011
• 卷：25
• 期：8
• 页码：3446-3455
• 全文大小：1300K
• 年卷期：v.25,no.8(August 18, 2011)
• ISSN：1520-5029

文摘

A coal sample was ashed at 600 掳C in air for 12 h, then pressed into pellets, and further treated in a reducing mixture of 60% CO and 40% CO₂ for 1 h at different temperatures ranging from 700 to 1200 掳C in 100 掳C intervals. Scanning electron microscopy linked with energy-dispersive X-ray analysis and X-ray diffraction were used to investigate the effects of key minerals on the ash melting behavior. No significant change was found in color and size of ash samples treated at 700鈥?00 掳C. However, from 1000 to 1100 掳C, substantial liquid-phase formation resulted in a greater shrinkage level and closed spherical pore formation in the pellet. A Na illite most likely existed in the parent coal. Most of Na and K coalesced with Si and Al during heating. A small number of Na鈥揔-enriched aluminosilicate particles were responsible for the formation of a liquid phase at 900 掳C. The Fe鈥揙 phase formed aluminosilicates less readily than lime. The temperature significantly influenced the fragmentation extent of calcite. The formation of substantial Fe minerals and Fe鈥揅a minerals required a particular temperature condition. In this study, this temperature condition was about 1000 掳C. Fe minerals and Fe鈥揅a minerals played an important role in determining the molten percentage of coal ash at relatively low temperatures. Evidence for this was that some molten Fe鈥揅a aluminosilicate particles were identified at 1000 and 1100 掳C and most Fe minerals and Fe鈥揅a minerals formed liquid phases.