褐煤模型化合物中官能团持水性质的理论研究

Theoretical Study on Water-holding Properties of the Functional Group of Lignite Model Compounds

采用密度泛函方法,研究了褐煤分子中官能团与水分子的相互作用;确定了不同官能团持水性的相对强弱,讨论了水分高低和结构环境对其持水性和脱水过程的影响,建立了脱水过程近似热力学关系式.计算结果表明,单个官能团的持水性呈现一定的饱和度,其周围化学环境对持水能力影响显著.压力增加会提高脱水温度,但影响不显著,加压有助于水分以水团簇形式脱去,降低脱水能耗.

Density functional calculations have been used to explore the interactions between the water and the functional group of lignite structural components,and the effects of water-holding capacity and local chemical environment on moisture adsorption and desorption of lignite model compounds have been discussed.An approximate thermodynamic relation has been derived based on the thermodynamic cycle to evaluate the temperature and pressure influence in dewatering process.The results indicate that the dependence of the critical dewatering temperature on pressure is not remarkable.Under elevated pressure,the desorbed water molecules may prefer in an aggregate state,which can lower the dewatering energy consumption.