摘要
针对二氧化碳-离子液体(CO_(2)-ILs)体系热力学性质数据较少的问题,采用状态方程+活度系数法(EOS+γ法)计算了CO_(2)-[C_(2)-mim][Tf_(2)N]、CO_(2)-[C_(4)-mim][Tf_(2)N]、CO_(2)-[C_(6)-mim][Tf_(2)N]和CO_(2)-[C_(8)-mim][Tf_(2)N]4种新型制冷工质对的汽液相平衡数据。在相平衡基础上,通过SRK(Soave-Redlich-Kwong)状态方程+WS(Wong-Sandler)混合规则+UNIFAC活度系数模型,关联得出混合体系的超额吉布斯自由能GE、超额焓HE和超额熵SE。计算结果表明,CO_(2)-ILs制冷工质对的超额性质均随温度、压力、CO_(2)液相摩尔分数以及离子液体中阳离子上烷基链长度等因素变化,GE均为负值,最大值为-1066.88 J·mol^(-1),且GE随温度、压力和ILs阳离子碳基链长度增大而减小,HE均为正值,最大值为407.24 J·mol^(-1),且H^(E)随温度、CO_(2)溶解度及ILs阳离子碳基链长度增大而减小,SE最大值为7.88 J·mol^(-1)·K-1,且SE随温度和压力的增大而减小、随ILs阳离子碳基链长度增大而增大。根据汽液相平衡时计算的压力平均相对偏差,可证明所选模型在计算CO_(2)-[C_(n)-mim][Tf_(2)N](n=2,4,6,8)系统超额性质的准确性。
In order to solve the problem of thermodynamic data limitation of carbon dioxide ionic liquid(CO_(2)-ILs)systems,phase equilibria of four new refrigeration working pairs(CO_(2)-[C_(2)-mim][Tf_(2)N],CO_(2)-[C_(4)-mim][Tf_(2)N],CO_(2)-[C_(6)-mim][Tf_(2)N]and CO_(2)-[C_(8)-mim][Tf_(2)N])were calculated by the selected equation of state+activity efficient method(EOS+γmethod).The excess Gibbs free energy(GE),excess enthalpy(HE)and excess entropy(SE)of the binary systems were correlated according to the selected SRK(Soave-Redlich-Kwong)equation of state+WS(Wong-Sandler)mixing rule+UNIFAC activity coefficient model based on phase equilibria.The results show that excess properties of this system are affected by factors including temperature,pressure,CO_(2)molar fraction and cationic carbon chain length of the ionic liquids.The calculation results show that GE decreases with the increase of temperature,pressure and length of ILs cationic carbon chain.The maximum of GE is^(-1)066.88 J×mol^(-1).H^(E) decreases with the increase of temperature,molar fraction of CO_(2)and length of ILs cationic carbon chain.The maximum of HE is 407.24 J×mol^(-1).SE decreases with the increase of temperature and pressure,and increases with the increase of length of ILs cationic carbon chain.The maximum of SE is 7.88 J×mol^(-1)×K^(-1).The accuracy of the model for excess property calculation can be proved by calculating ARD pressure values at vapor-liquid equilibrium.
作者
何丽娟
杨建滋
韩雨泽
杨文轩
HE Lijuan;YANG Jianzi;HAN Yuze;YANG Wenxuan(Institute of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China;Institute of Information Science and Engineering,Guilin University of Technology,Guilin 541006,China)
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2024年第1期40-48,共9页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金(51566014)
内蒙古自然科学基金(2021MS05035)
内蒙古自治区直属高校基本科技项目。
