CIESC Journal ›› 2019, Vol. 70 ›› Issue (9): 3228-3237.DOI: 10.11949/0438-1157.20181314

• Thermodynamics • Previous Articles     Next Articles

Selection of cubic equations of state for separation of CO2-C2H6 azeotrope

Haiqin WANG1,2(),Minglong FAN2,Zubin ZHANG1,2()   

  1. 1. Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety
    2. School of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, Shandong, China
  • Received:2018-11-12 Revised:2019-05-17 Online:2019-09-05 Published:2019-09-05
  • Contact: Zubin ZHANG

CO2-C2H6共沸物分离的立方型状态方程选取

王海琴1,2(),范明龙2,张足斌1,2()   

  1. 1. 山东省油气储运安全省级重点实验室
    2. 中国石油大学(华东)储运与建筑工程学院, 山东 青岛 266580
  • 通讯作者: 张足斌
  • 作者简介:王海琴(1969—),女,博士,副教授,whq@upc.edu.cn
  • 基金资助:
    国家自然科学基金项目(51306210)

Abstract:

Accurate selection of vapor-liquid equilibrium thermodynamic model is essential to the design and operation of CO2-C2H6 azeotrope separation process. On the basis of collected experimental data, the reliabilities of four types of cubic equations of state including vdW, RK, SRK and PR combined with vdW, Margles and CVD mixing rules for predicting vapor-liquid equilibrium properties of CO2 pure substance, CO2-C2H6 azeotrope and n-C5H12-CO2-C2H6 ternary system are evaluated according to the principle of vapor-liquid fugacity equilibrium. In addition, average absolute deviation is adopted to select cubic state equations. The results show that the SRK equation of state calculates the vapor-liquid equilibrium property of CO2 pure material with the highest precision. The PR equation of state combined with Margles mixing rule can accurately calculate the vapor-liquid equilibrium characteristics of CO2-C2H6 azeotrope system. However, for n-C5H12-CO2-C2H6 ternary system, the calculating accuracy of SRK combined with Margles mixing rule is obviously better than that of vdW, RK and PR. Furthermore, binary interaction parameters have obvious effects on the calculating accuracy of cubic equations of state for the mixture system. In order to improve the calculation accuracy, the binary interaction parameter is calibrated for all of the studied EOSs regarding CO2-C2H6 azeotropic system and n-C5H12-CO2-C2H6 ternary system.

Key words: CO2-C2H6 azeotrope, cubic equation of state, fugacity equilibrium, mixing rule, binary interaction parameters, average absolute deviation

摘要:

汽液平衡热力学模型的准确选取对CO2-C2H6共沸物分离流程的设计和操作分析至关重要。在汽液平衡实验数据的基础上,依据逸度平衡原则,评估vdW、RK、SRK和PR立方型状态方程结合vdW、Margles和CVD混合规则预测CO2纯物质、CO2-C2H6共沸物和n-C5H12-CO2-C2H6三元体系汽液平衡的可靠性,采用平均绝对误差的方法进行状态方程的选取。结果表明:SRK状态方程计算CO2纯物质汽液平衡性质的精度最高;PR状态方程结合Margles混合规则可以准确计算CO2-C2H6共沸体系汽液平衡特性;对于n-C5H12-CO2-C2H6三元体系,SRK状态方程结合Margles混合规则计算精度明显优于vdW、RK和PR状态方程。通过试差迭代法优化CO2-C2H6共沸体系和n-C5H12-CO2-C2H6三元体系的二元交互作用参数,状态方程的计算精度得到明显提高。

关键词: CO2-C2H6共沸物, 立方型状态方程, 逸度平衡, 混合规则, 二元交互作用参数, 平均绝对误差

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