利用状态方程计算石油馏分相平衡的连续热力学方法

A CONTINUOUS THERMODYNAMIC METHOD FOR THE PHASE EQUILIBRIUM CALCULATION OF PETROLEUM FRACTIONS BASED ON EQUATION OF STATES

对石油馏分的相平衡计算，传统的方法是采用虚拟组分，利用状态方程进行求解。针对石油馏分组成复杂、沸点互相重叠交叉严重的特点，提出了直接利用馏分实沸点蒸馏曲线（ＴＢＰ曲线）作为分布函数进行混合物相平衡计算的连续热力学方法（ＣＤＭ法）。讨论了利用ＳＲＫ状态方程计算相平衡的连续热力学步骤，并对原油和馏分油进行了闪蒸及泡点计算。与虚拟组分法（ＰＳ法）相比，新方法的计算量小，计算速度快，计算结果与实验结果比较符合，是一种对石油馏分热力学进行预测和模拟的较好方法。

Traditional method of phase equilibrium calculation for complex petroleum mixtures is pseudo components method.In this paper,a new continuous thermodynamic method is proposed,in which the true boiling point distillation curve has been taken as a continuous distribution function,and the independent variable is the temperature of the normal boiling point.This new method can be used for any arbitrary distribution of fraction.The way for calculation phase equilibrium using SRK equation of state based on continuous thermodynamics is also discussed.Flash distillation of a real crude system and the bubble point for a dewaxing oil fraction are illustrated in the calculation.Compared with pseudo components method,the computation accuracy and efficiency have been improved with this proposed new method used.Good agreement is observed between calculation and experimental results.