Melting Behavior of Typical Ash Particles in Reducing Atmosphere

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• 作者：Haigang Wang ; Penghua Qiu ; Shijun Wu ; Yun Zhu ; Yaoqiang Li ; Guangbo Zhao
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：June 21, 2012
• 年：2012
• 卷：26
• 期：6
• 页码：3527-3541
• 全文大小：1356K
• 年卷期：v.26,no.6(June 21, 2012)
• ISSN：1520-5029

文摘

Two coal ashes (one with high-melting temperature and one with low-melting temperature) obtained at 600 掳C in air were pressed into pellets and further treated for 1 h at different temperatures from 700 to 1200 掳C at the interval of 100 掳C in reducing atmosphere (mole ratio CO:CO₂ = 60:40) to investigate the melting behavior of typical ash particles. The final structures were characterized by XRD and SEM-EDX. The results showed that most Na, K, Ca, and Fe took the form of aluminosilicates. Although the low-melting particles (Na鈥揔-enriched aluminosilicate particles and Ca鈥揊e-enriched aluminosilicate particles) were small in number percentage, these particles were already melted at 1000 掳C. It is possible that Fe was enriched more readily in particles than Ca. The extent of fragmentation of calcite particle was closely related to the calcite type. The calcite particles with layered textures fragmented more. Gaussian distribution successfully simulated the calcite particle size distribution after calcite particle fragmentation. The detailed mechanism analysis showed that the Fe鈥揙 particle dissolution was primarily controlled by diffusion. The Fe鈥揙 crystals from pyrite and siderite showed similar patterns of crystal growth.