C-H-O-N-S流体混合物的PVTx和气液相平衡性质预测

发布时间：2018-03-01 16:27

本文关键词： 天然气状态方程 PVTx性质气液相平衡　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：天然气混合物可近似为C-H-O-N-S体系,主要含CH_4、C_2H_6、C_3H_8、CO_2、N_2,以及H_2S和SO_2(少量)。因此确定含硫天然气流体混合物的压力-体积-温度-组成(PVTx)和气液相平衡(VLE)性质,对于探讨油气来源、油气储运和油气开采具有重要的意义。同时,含硫天然气流体混合物的PVTx和VLE性质,也是油气包裹体研究中确定捕获温度与捕获压力的基础。通常确定流体PVTx和VLE性质的方法有实验和热力学计算模拟。由于实验数据的有限性,本文借助于最常用的有良好外延性的Helmholtz状态方程,对流体混合物的PVTx和VLE性质进行预测:在吕孟欣(2015)和Lemmon and Jacobsen(1999)热力学模型的基础上,依据对应态原理和已有的实验数据,建立了一个通用的含硫天然气流体混合物(CH_4-C_2H_6-C_3H_8-N_2-CO_2-H_2S-SO_2)的Helmholtz自由能方程。该方程形式上是温度、密度和组成的函数,不仅形式简单、适用范围宽广,而且预测精度高,与实验数据精度相当。方程中四个混合参数通过可靠的二元体系的PVTx和VLE数据,采用非线性最小二乘法拟合得到。多元流体混合物的热力学性质的计算完全是预测性的。本方程适用于从三相点温度和压力到650K和2000 bar的温度压力范围,预测的精度与kunz et al.(2007)建立的GERG-2008状态方程的精度接近。采用国际上流行的计算语言Fortran95编写整个状态方程的计算程序。程序语言结构简单,可以很方便地应用于相应体系的包裹体研究。
[Abstract]:The natural gas mixture can be approximated as a C-H-O-N-S system, consisting mainly of CHS 4C2H2H6 / C3H8S / CO2S / N2, as well as a small number of H2S and SO2S. Therefore, the properties of pressure-volume-temperature-composition PVTx and gas-liquid equilibrium VLEs of a mixture of sulfur-containing natural gas fluids are determined, and for the purpose of exploring the source of oil and gas, It is of great significance to store and transport oil and gas and produce oil and gas. At the same time, the PVTx and VLE properties of the fluid mixture containing sulfur natural gas, It is also the basis of determining the trapping temperature and pressure in the study of oil and gas inclusions. Usually, the methods of determining the properties of PVTx and VLE of fluid are experimental and thermodynamic simulation. Because of the limitation of experimental data, In this paper, with the aid of the most commonly used Helmholtz equation of state with good extrapolation, the PVTx and VLE properties of fluid mixtures are predicted: based on the thermodynamic models of Mengxin Lu 2015 and Lemmon and Jacobsen 1999), the corresponding state principle and the available experimental data are used. The Helmholtz free energy equation of a general sour natural gas fluid mixture, Ch _ 4-C _ s _ 2H _ 6-C _ _ _. The four mixed parameters in the equation pass through the PVTx and VLE data of the reliable binary system. The calculation of thermodynamic properties of multicomponent fluid mixtures is completely predictive. This equation is applicable to the temperature and pressure range from three-phase temperature and pressure to 650 K and 2000 bar. The accuracy of the prediction is close to that of the GERG-2008 equation of state established by kunz et al.2007). The calculation program of the whole equation of state is compiled by using the international popular computing language Fortran95. The structure of the program language is simple. It can be easily applied to the study of inclusions in the corresponding systems.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE31

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