液化天然气中CO_(2)的溶解度计算新方法  

A new method for calculating the solubility of carbon dioxide in liquefied natural gas

作　　者：蔡伟华 高磊[1] 王照曦 段欣悦 边江[2] 花亦怀 车勋建 CAI Weihua;GAO Lei;WANG Zhaoxi;DUAN Xinyue;BIAN Jiang;HUA Yihuai;CHE Xunjian(School of Energy and Power Engineering,Northeast Electric Power University,Jilin,Jilin 132012,China;College of Pipeline and Civil Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Technology R&D Center,CNOOC Gas&Power Group,Beijing 100028,China)

机构地区：[1]东北电力大学能源与动力工程学院 [2]中国石油大学(华东)储运与建筑工程学院 [3]中海石油气电集团技术研发中心

出　　处：《天然气工业》2023年第7期108-116,共9页Natural Gas Industry

基　　金：国家自然科学基金企业创新发展联合基金重点项目“新型FLNG装置天然气带压液化复杂流动与换热的基础问题”(编号:U21B2067)。

摘　　要：液化天然气技术是深远海天然气利用最为可行的技术方案,其中带压液化天然气(PLNG)技术可显著提升LNG中CO_(2)的溶解度,但利用相平衡实验获得CO_(2)溶解度的方法较为复杂,且理论方法难以在宽温区范围内保证CO_(2)溶解度计算的准确度。为了能快速计算具有高准确度的液化天然气中CO_(2)的溶解度,提出了分温区拟合二元交互作用系数的方法,应用HYSYS软件和理论自编程法分别对CH_(4)—CO_(2)二元系和CH_(4)—CO_(2)—N_(2)/C_(2)H_(6)三元系溶液中CO_(2)的溶解度进行计算。研究结果表明:(1)采用HYSYS软件和理论自编程法分别计算的CO_(2)在二元系溶液和三元系溶液中的溶解度,与实验数据的平均相对误差均小于8%;(2)使用拟合的二元交互系数后,HYSYS软件计算CO_(2)在液态CH_(4)中的溶解度数据与实验值的平均相对误差从6.63%降到1.69%,且HYSYS软件和理论自编程法计算三元系溶液中CO_(2)的溶解度准确性均得到了提高。结论认为,通过使用分温区拟合二元交互作用系数,HYSYS软件和理论自编程法可快速计算高准确度的CO_(2)溶解度数据,该新方法为天然气液化工艺流程的设计提供了理论指导和技术支撑。The liquefied natural gas(LNG)technology is the most feasible technical solution to deepsea natural gas utilization,and the pressurized liquefied natural gas(PLNG)technology can significantly enhance the solubility of CO_(2) in LNG.However,it is complicated to obtain the CO_(2) solubility through phase equilibrium experiments,and the theoretical calculation method can hardly ensure the calculation accuracy of CO_(2) solubility in a wide temperature range.In order to calculate the solubility of CO_(2) in LNG with high accuracy quickly,this paper proposes the method of fitting binary interaction coefficients by partitioned temperature zones,and calculates the solubility of CO_(2) in CH_(4)-CO_(2) binary system solution and CH_(4)-CO_(2)-N_(2)/C_(2)H_(6) ternary system solution by using HYSYS software and the theoretical self-programming method,respectively.And the following research results are obtained.First,the solubility of CO_(2) in binary and ternary system solutions are calculated by using HYSYS software and the theoretical self-programming method respectively,and their average relative errors to the experimental data are less than 8%.Second,after the fitted binary interaction coefficients are introduced,the average relative error between the solubility of CO_(2) in liquid CH_(4) calculated by HYSYS software and the experimental value is decreased from 6.63% to 1.69%,and the accuracy of the solubility of CO_(2) in the ternary system solution calculated by HYSYS and theoretical selfprogramming is also improved.In conclusion,the HYSYS software and theoretical self-programming method can quickly calculate CO_(2) solubility with a high degree of accuracy by using binary interaction coefficients fitted to the partitioned temperature zones.This new method provides theoretical guidance and technical support for the design of LNG process.

关 键 词：液化天然气 CO_(2) 溶解度 二元交互系数 HYSYS 理论自编程 甲烷 分温区 

分 类 号：TE64[石油与天然气工程—油气加工工程]