基于CPA状态方程预测烷烃-水体系相平衡  

Prediction of multiphase equilibrium of n-alkene/water binaries by using CPA EoS

作　　者：吴瑕[1] 牛淑昊 贾文龙[1] 李长俊[1] 彭冬婳[2] 陈鹏 WU Xia;NIU Shu-hao;JIA Wen-long;LI Chang-jun;PENG Dong-hua;CHEN Peng(College of Petroleum Engineering,Southwest Petroleum University,Chengdu 610500,Sichuan Province,China;PetroChina Southwest Oil&Gas Filed Company,Chengdu 610000,Sichuan Province,China;PetroChina Southwest Pipeline Company,Chengdu 610000,Sichuan Province,China)

机构地区：[1]西南石油大学石油与天然气工程学院,四川成都610500 [2]中国石油西南油气田分公司,四川成都610000 [3]中国石油西南管道分公司,四川成都610000

出　　处：《化学工程》2018年第9期43-47,共5页Chemical Engineering(China)

基　　金：国家自然科学基金青年基金项目(51604233;51504206);国家自然科学基金面上项目(51474184)

摘　　要：采用考虑了极性分子间氢键缔合作用的立方型附加缔合项(CPA)状态方程计算了烷烃-水体系的气液相平衡。通过调整CPA状态方程中的二元交互作用系数,拟合了n-C_7,n-C_(10),n-C_(16),n-C_(20),n-C_(24),n-C_(28),n-C_(32),n-C_(36)与水二元混合物的气液液三相平衡(VLLE)曲线,提出了适用于n-C_7以上烷烃的烃-水体系二元交互作用系数关联式;对于n-C_(36)以上的烷烃,二元交互作用系数建议取值为-0.038。以此为基础,预测了n-C_6,n-C_7,n-C_8,n-C_9,n-C_(10),nC_(12),n-C_(16),n-C_(20)与水二元混合物液相中的水的摩尔分率,预测值与实验值之间平均绝对偏差为0. 018 10。取得成果能够同时对烃-水体系的VLLE曲线和烃水互溶度进行准确的预测,为下一步研究多组分天然气-水、油-水混合物的相态特征奠定了基础。A Cubic-Plus-Association(CPA)Equation of Sate(EoS)that represents the hydrogen-bond association between polar components was applied to calculate the multiphase equilibrium of n-alkane/water binaries.The Vapor-Liquid-Liquid Equilibrium(VLLE)curves of n-C 7,n-C 10,n-C 16,n-C 20,n-C 24,n-C 28,n-C 32,n-C 36 and water binaries were fitted by using the CPA EOS and adjusting the binary interaction parameters(BIP)of the CPA EoS.As a result,a BIP formula used for the n-alkane heavier than n-C 7 and water binaries was proposed.In particular,a constant BIP value-0.038 was suggested for n-alkane heavier than n-C 36.Furthermore,the CPA EoS and the BIP formula were applied to predict the water content in the hydrocarbon-rich liquid phase of n-C 6,n-C 7,n-C 8,n-C 9,n-C 10,n-C 12,n-C 16,n-C 20 and water binaries.The results demonstrate that the average absolute deviation between the experimental and calculated water mole fraction in the liquid phase is 0.018 10 in terms of mole fraction.The achievement is not only able to predict the VLLE curves and mutual solubility of water and hydrocarbon binaries,but also provides a basis for the multiphase behavior research of gas-water and oil-water mixtures.

关 键 词：CPA状态方程 二元交互作用系数 烷烃 水 气液相平衡 

分 类 号：TQ013.1[化学工程]