天然气体系中环己烷的气液固三相平衡计算

Calculation on gas-liquid-solid phase equilibrium of cyclohexane in natural gas

关键词:  液化天然气  环己烷  三相平衡  固相逸度  固相析出 

Key words:  liquefied natural gas  cyclohexane  three-phase equilibrium  solid fugacity  solid precipitation

摘要:

国内天然气能源消耗的增加导致供需矛盾日益严重,LNG运输已成为中短距离运输天然气的主要形式。但在天然气液化过程中,天然气中的重烃在低温下会析出固相堵塞设备和管道,造成安全隐患。为此,研究建立了天然气体系三相相平衡理论模型并进行了计算,通过自主研发的热力学计算软件,使用PR方程,对我国某地区的天然气体系中的环己烷进行了气液固三相平衡计算,并计算了该体系中环己烷的一些热力学数据及固相析出条件。通过与国外商业软件进行计算对比,结果准确度较高,可以为天然气的液化工艺设计提供可靠的数据支持和基础的理论依据。所建立的热力学模型、获得的基础数据和研究结果,对我国的LNG工业领域的基础研究具有一定的理论意义。 

Abstract:

The contradiction between supply and demand caused by the rise in domestic natural gas consumption is increasingly serious. Thus LNG has been the main method of short-distance natural gas transport. While in the process of liquefying natural gas, solid phase precipitating from heavy hydrocarbon at low temperatures blocks equipment and pipeline, which causes potential security risks. To remove the peril, the gas-liquid-solid three-phase equilibrium model of the natural gas system was built and calculated. By independent research and development of the thermodynamic calculation software and the use of this model and PR equation, cyclohexane of the natural gas system in a certain area, thermodynamic data and the conditions of solid separation were carried out. By comparison with calculation results of foreign commercial software, it has shown high accuracy and could provide theoretical foundation and basic data support for natural gas liquefaction process design. Therefore, the thermodynamic model, basic data and results obtained from this research have significant theoretical meaning for the LNG industry of China.