RG-CPA方程计算超临界CO_2-醇体系汽液相平衡  

Modelling VLE of supercritical CO_2 + alkanol mixtures using RG-CPA EOS

作　　者：许心皓[1] 段远源[1] 杨震[1] 

机构地区：[1]清华大学热能工程系,北京100084

出　　处：《化工学报》2012年第5期1331-1337,共7页CIESC Journal

基　　金：国家重点基础研究发展计划项目(2009CB219805);国家自然科学基金项目(51076074)~~

摘　　要：综合考虑缔合作用和密度涨落的影响,将经重整化群修正的CPA方程(RG-CPA方程)扩展到二元体系汽液相平衡的计算。通过一个温度下的汽液相平衡数据回归得到二元交互作用参数,预测其他温度下的相平衡。采用这种方法计算了超临界CO2与醇二元体系的汽液相平衡性质和临界曲线。结果表明,RG-CPA方程预测超临界CO2与醇二元体系的气液相组成和密度具有较高的精度,液相组分平均绝对偏差为0.032,气相组分平均绝对偏差为0.019。与原始CPA方程相比,RG-CPA方程能更好地预测气液临界曲线。Considering the contribution of association and the density fluctuations,an equation of state（EOS）based on the original cubic-plus-association（CPA）EOS and the renormalization group theory（RG）was extended to binary mixtures.The binary interaction parameters were obtained by fitting the vapor-liquid equilibrium（VLE）data at one temperature,and then were used to predict the VLE data at other temperatures.The RG-CPA EOS was used to predict the VLE and the critical line of the supercritical CO2-1-alkanol（n=1—8）binary mixtures,which are nonideal systems with association.Using temperature independent binary interaction parameters,satisfactory results for composition and density of both vapor and liquid phases were obtained by the RG-CPA EOS.The overall average absolute derivations of composition in liquid and vapor were 0.032 and 0.019 respectively.In addition,the RG-CPA EOS can successfully reproduce the vapor liquid critical line of these binary mixtures,which is much better than the original CPA EOS.

关 键 词：汽液相平衡 超临界CO2 缔合 重整化群 

分 类 号：TQ013.1[化学工程]