用基团贡献法预测原油平衡闪蒸气化率

用正构烷烃模型分子法确定假组分的基团组成，根据ＵＮＩＦＡＣ基团贡献法饱和蒸气压模型与活度系数模型，以及修正的活度系数模型，计算了假组分的相平衡常数Ｋ，并预测了大庆原油平衡闪蒸气化率。结果表明，用平均沸点确定基团组成，ＲｉａｚｉＤａｕｂｅｒｔ关联式计算相对分子质量的ＲａｕＫ模型的预测值与实验值的偏差最小，为３．３６％；用ＡＰＩ式计算相对分子质量的ＫｉｋＫ模型和ＬａｒＫ模型次之，预测偏差低于５．５％，均可满足工程计算的要求。而且运用正构烷烃模型分子ＵＮＩＦＡＣ基团贡献法时，仅需平均沸点或相对分子质量之中的一个物性参数即可确定假组分的基团组成，计算过程更加简单。

/ PREDICTION OF FLASH VAPORIZATION RATIOS OF CRUDE OIL WITH GROUP CONTRIBUTION METHOD

The group composition of a pseudo component molecule is determined by the normal paraffin model molecule method. By the use of the UNIFAC vapor pressure model activity coefficient model and modified activity coefficient model, the phase balance constants are calculated. The flash vaporization ratios of Daqing crude oil are predicted. It shows that the relative average deviation from Rau K model is 3.36% (molecular weight is calculated by Riazi Daubert and the average boiling point is determined by the group composition). The relative average deviations from Kik K and Lar K models are below 5.5%, which are satisfactory for engineering. The model needs only one of parameters, average boiling point or molecular weight, for determining the group composition of a pesudo component molecule.