丙烷超临界状态下乙烯淤浆聚合体系组分的物性计算

Physical properties computation of pure components for ethylene slurry polymerization system on supercritical condition of propane

以生产HDPE过程中丙烷溶剂处于超临界状态下乙烯淤浆聚合过程为研究对象,应用POLYMER PLUS为计算平台,建立含聚乙烯的复杂体系的热力学物性参数的计算方法。通过研究,可见PC-SAFT方程可以准确地计算所研究聚合物系统各组分的热力学物性;处于超临界状态的丙烷的热力学参数可以通过饱和蒸汽压、液相密度以及超临界密度数据拟合得到,且计算丙烷的饱和液相密度和超临界密度的偏差在1.9%以内;聚乙烯的热力学方程参数以及聚乙烯与丙烷的交互参数可以通过聚合物和丙烷在液态和超临界状态时的液相密度拟合得到,计算的聚乙烯和丙烷的混合密度偏差在0.78%以内;应用PC-SAFT方程计算操作条件范围内的聚乙烯热能和聚合热的偏差也在3%以内。

It indicates that PC-SAFT can accurately predict the physical properties of the components involved in the slurry polymerization process based on the research of ethylene slurry polymerization system on supercritical condition of propane by POLYMER PLUS software.The thermodynamic parameter of propane component on supercritical condition can be confirmed by saturation pressure,liquid density and supercritical density,the calculation deflection is under 1.9%.The thermodynamic parameter of polyethylene and binary k_（ij） parameter of the propane and polyethylene can be confirmed by the density of polymer slurry and the density of propane under liquid and supercritical condition,the calculation deflection of mixed density of propane and polyethylene is under 0.78%.The heat capacity and Heat of Ethylene Polymerization also can be estimated well by PC-SAFT EOS.