重组分对天然气相态特征的影响

组分分析是进行相平衡计算，分析天然气相态特征的基础。以相平衡计算为基础，采用PR方程计算了不同组分含量天然气的相态曲线。为了说明重组分含量的多少是否能反映天然气的相态特征，特别假设了第三组气样，它们的重组分总含量基本一致，但具体组分不同。分析表明，少量重组分的存在，会明显地提高天然气的临界冷凝压力和临界冷凝温度，少量的重组分对天然气的相态特征有很大的影响；不同重组分的具体影响有所不同。应避免将C₆或C₇以上组分合并为一项处理，仅根据重组分的总含量并不能准确反映出天然气的相态特征，对重组分的分析应尽可能精确。

INFLUENCE OF HEAVY HYDROCARBONS ON PHASE BEHAVIOR OF NATURAL GAS

Composition analysis is the foundation for phase equilibrium computation and phase behavior analysis of natural gas.Based on the phase equilibrium,this study calculated by the PR equation on several phase curves of different-content natural gases.In order to explain whether the quantity of heavy hydrocarbons can reflect the phase behavior of natural gas,this study assumed the gas samples of Group 3,in which there are different compositions but the same amount of heavy hydrocarbons.This analysis showed that a tiny amount of heavy hydrocarbon in natural gas could not only obviously help increase the critical condensate temperature and pressure but also have great effect on the phase behavior of natural gas with different influence by different compositions of heavy hydrocarbons.This study suggests that the analysis on heavy hydrocarbons should be required with such high accuracy that neither is the component of C6 or C7 incorporated as one component nor the total quantity of heavy hydrocarbons is regarded as only one criterion.