摘要
LNG(液化天然气)密度的精确计算对于能源贸易至关重要,可采用ISO 20765-2标准中推荐的GERG-2008状态方程对密度进行计算。然而现有算法在求解LNG密度时不能稳定获得正确解,通过采用不同迭代初值及二分区间,发现GERG-2008在LNG求解温度范围内,存在多个密度解。文中通过研究GERG-2008方程特点,分析LNG密度解的存在情况,并通过给定牛顿迭代初值,使GERG-2008能够稳定求得LNG密度解。使用该方法计算100—180 K、0—10 MPa条件下共计12种LNG组分,并将密度计算结果与实验值进行对比。结果表明:计算值与实验值之间的平均相对偏差为0—2.1%,相比于PC-SAFT、SRK方程计算精度分别提高了0.66%、4.79%。在LNG温度和压力下,GERG-2008方程的计算精度受温度与压力的影响小,可作为LNG密度求解的理想方法。
Accurate calculation of LNG(liquefied natural gas)density is essential for energy trade,and the GERG-2008 equation of state,recommended by ISO 20765-2,can be utilized for the calculation.However,the existing algorithms cannot consistently obtain the correct solutions when calculating LNG density.By employing various initial values for iteration and utilizing bisection methods,it is found that multiple density solutions exist within the temperature range relevant for LNG using GERG-2008 equation.This study explored the characteristics of GERG-2008 equation to analyze the conditions under which multiple density solutions arising.By providing appropriate initial values for Newton′s iteration,GERG-2008 equation can stably obtain the determination of LNG density.The method was applied to calculate the densities of 12 different LNG components under conditions ranging from 100-180 K and 0-10 MPa,and the calculated results were compared to experimental values.The results indicate that the average relative deviation between calculated and experimental values ranges from 0-2.1%,representing improvements in accuracy of 0.66%and 4.79%compared to PC-SAFT and SRK equations,respectively.Under the temperature and pressure conditions of LNG,the calculation accuracy of GERG-2008 equation is minimally affected by temperature and pressure,making it as an ideal method for solving LNG density.
作者
贾文龙
王秀娟
吴瑕
杨帆
廖钰朋
高谦
JIA Wenlong;WANG Xiujuan;WU Xia;YANG Fan;LIAO Yupeng;GAO Qian(School of Petroleum and Natural Gas Engineering,Southwest Petroleum University,Chengdu 610500,Sichuan Province,China)
出处
《化学工程》
北大核心
2025年第9期39-45,共7页
Chemical Engineering(China)
基金
国家自然科学基金资助项目(52274065,52074238)。
作者简介
贾文龙(1986-),男,博士,教授,研究方向为油气管道输送等,电话:13980811257,E-mail:jiawenlong@126.com。
