先锋褐煤的热处理和水热处理改质

Modification of Xianfeng lignite by thermal treatment and hydrothermal treatment

通过先锋褐煤热处理和水热处理,结合处理煤结构与性质表征,研究了热处理和水热处理对先锋褐煤结构、抽提和溶胀性能的影响,探讨了热处理过程水的作用。结果表明,低于热解温度下的热处理以非共价键解缔合及部分弱共价键热解为主,水与煤的水热反应能够抑制水热处理过程中煤的热解和小分子化合物释放。高温热处理以热解和脱氧为主,水热反应可以稳定煤热解活性基团,避免其二次裂解和交联,在一定程度上提高处理煤的混合溶剂抽提率,改善其溶胀性能。

Modification of low rank coal by thermal treatment is the key to its high-efficiency conversion and utilization. In this paper, the thermal treatment and hydrothermal treatment of Xianfeng lignite were carried out. By combination of the characterizations of structure and properties of treated coals, the modification of thermal treatment and the interaction of water in the hydrothermal process were investigated. The results indicate that the disassociation of non-covalent bonds and the pyrolysis of weak covalent bonds dominate in the treatment process below the pyrolystic temperature of lignite. The hydrothermal reaction can inhibit the pyrolysis of coal matrix and the release of small molecular compounds in the process of hydrothermal treatment. At higher than the pyrolysis of lignite, the thermal treatment shows obvious pyrolysis and deoxygenation. The hydrothermal reaction can provide active hydrogen to stabilize the pyrolysis fragment and avoid the secondary pyrolysis and condensation, so that the extraction and swelling properties of hydrothermal treated coal in mixed solvent were improve at certain extent.