用PR方程新的混合规则预测高压汽液平衡  

Prediction of high pressure vapor-liquid equilibria using a new mixing rule for the PR equation of state

作　　者：于养信[1] 陈中[1] 高光华[1] 

机构地区：[1]清华大学化学工程系,北京100084

出　　处：《清华大学学报（自然科学版）》2002年第5期595-598,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金重点资助项目 ( 2 9736 170 )

摘　　要：为了预测高压汽液平衡 ,提出了 PR方程新的混合规则。它建立在无限大压力下由状态方程计算出的超额Helmholtz自由能与由活度系数模型得到的超额 Helm holtz自由能相等的基础上 ,并假定液体体积与状态方程参数 b成正比。使用 U NIFAC方程计算超额 Helmholtz自由能 ,利用该混合规则 ,对 6个体系在不同温度和压力下的汽液平衡进行了预测。结果表明混合规则可成功地用于高压汽液平衡的预测 ,其精度比A new mixing rule for the PR equation of state is proposed to predict vapor-liquid equilibria at high pressures. The mixing rule is based on equating the excess Helmholtz free energy at infinite pressure from the PR equation of state to that from an activity coefficient model, assuming that the liquid volume is proportional to the parameter b in the equation of state. By using the UNIFAC equation to calculate the excess Helmholtz free energy, the present mixing rule was applied to predict the vapor-liquid equilibria of six binary systems at different temperatures and pressures. The results show that the present mixing rule can be successfully used to predict vapor-liquid equilibria at high pressures, and its accuracy is slightly better than that of the MHV2 model.

关 键 词：高压汽液平衡 PR方程 混合规则 预测 立方状态方程 超额Helmholtz自由能 非理想体系 

分 类 号：O642.4[理学—物理化学]