天然气体系三相平衡计算交互作用因子K_(ij)的取值

Calculation of interaction parameter on phase equilibrium in natural gas

为解决LNG产业链中的重烃析出问题,研究建立了天然气体系三相相平衡理论模型并自主研发了热力学计算软件。计算模型中的K_(ij)代表纯物质变成混合物时所有的物理性质变化,是温度、组成以及组分性质的函数。目前对于物质混合过程的物理化学变化没有全面的认识,所以K_(ij)没有具体的表达式。计算了天然气混合体系中不同K_(ij)的相平衡计算,以选取合适的K_(ij)值来提高模型计算结果的准确性。

To solve the heavy hydrocarbon precipitation problems in LNG industry,the theoretical model of three phase equilibrium is established and the thermodynamic calculation software is developed independently.The interaction parameter K_（ij） in calculation model represents all the physical properties changing when the pure substance becomes mixture,and it＇s the function of T,x and component properties.It can＇t be calculated by a formula as physical chemistry changes of the mixing process have not been understood comprehensively now.The phase equilibrium in different K_（ij） is calculated in order to select the appropriate K_（ij）to improve the accuracy of the model calculation results.