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在有些油气田在，二氧化碳的含量比较高。如我国莺－琼盆地的崖13－1油气田的二氧化碳含量为9．6％，东海平湖油田中二氧化碳含量为3．95％。当其在多组分混合物中的分压小于0．516MPa，温度低于－56．5℃时，将成为固相，堵塞管道；同时在天然气液化流程中液化二氧化碳是不经济的。为此在天然气液化前要除去它，通过相变分离是除去二氧化碳的一种方法。文章测量了N2、CH4和CO2三元体系在温度为227．15K，压力为2．0MPa、2．5MPa、3．0MPa下的相平衡数据；用试验数据关联了试验温度下SRK方程和PR方程中的CO2与N2、CO2与CH4的二元交互作用系数；并对试验数据在联及验证性计算。最后进行了计算值与试验值之间的比较。

An Experiment on Vapor-liquid Equilibrium of CH4-N2-CO2

??The CO₂ content in some oil and gas field in China is relatively high.For instance,the CO₂ content in 13-1 oil and gas field in Yin Qiong basin is 9.6% and that in Pinghu oil field in East China Sea is 3.95%.When the fractional pressure of CO₂ in multi component mixture is less than 0.516 MPa and the temperature is lower than -56.5??,CO₂ will become solid phase and will plug pipeline.Moreover,liquef action of CO₂ in the process of liquefying natural gas is not economic.For this reason,CO₂ should be eliminated before liquefying natural gas.Phase chan ge seperation is a method for eliminating CO₂.In this paper,the phase equil ibrium data of N₂,CH₄ and CO₂ at the temperature of 227.15K and the pressure of 2.0MPa,2.5MPa and 3.0MPa are measured.By using these data,the dua lity interaction coefficients-KN₂ CO₂ and K CH₄ CO₂ in the SRK and PR equations at the experimental temperature are calculated and the experiment data are correlated and verified.At last,the calculated value is compared with the experimented one.