基于不同的SAFT类状态方程研究甲烷的热物性

Thermophysical properties of methane studied by different SAFT-type equation of state

主要选取了Soft-SAFT,PC-SAFT,SAFT-VR Mie 2006,SAFT-VR Mie 2013四种典型的SAFT类状态方程,并结合Matlab编程,在90-190 K温度区间内,计算了甲烷的热物性并对比分析了不同状态方程的预测性能。结果显示,在整个饱和态区间内,PC-SAFT对于甲烷相平衡和二阶偏导特性总体上具有最小的预测偏差;改进后的Mie 2013方程比Mie 2006方程显示出更好的预测精度;而Soft-SAFT方程仅对甲烷饱和液相密度具有较好的预测特性;SAFT类状态方程对于甲烷相平衡特性的预测均优于对应的二阶偏导特性;另外,更多的方程参数及更复杂的方程形式并不能保证更精确的预测结果。

The four typical SAFT-type equation of state （EoSs） were selected Soft-SAFT, PC-SAFT, SAFT-VR Mie 2006,SAFT-VR Mie 2013. With the Matlab programming, we calculated the thermophysical properties and evaluated the capability of different EoSs were calculated in the temperature range of 90--190 K. The results showed that： PC-SAFT has the smallest deviation for both phase behavior and second-deriva- tive properties of methane over the whole saturated state. The modified Mie 2013 EoS has showed a better prediction than Mie 2006 EoS. For Soft-SAFT EoS, only the saturated density was satisfactorily predicted. It was also observed that phase equilibrium properties were better predicted than the corresponding second- derivative properties for all the SAFT-type EoSs. In addition, the more parameters and complicated forma- tion cannot always ensure more accurate results.