Phase stability with cubic equations of state: Global optimization approach
Phase stability with cubic equations of state: Global optimization approach
复制标题
三次状态方程的相稳定性：全局优化方法
DOI：
10.1002/aic.690460715
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发表时间：
2000
期刊：
影响因子：
3.7
通讯作者：
C. Floudas
中科院分区：
文献类型：
--
作者：
S. T. Harding;C. Floudas
相平衡和化学平衡的计算对于化工过程的设计和模拟是至关重要的。最小化吉布斯自由能的方法提供了平衡解，这些平衡解仅是真正平衡解的候选者，因为在吉布斯自由能最小化问题可以公式化之前必须假设相的数量和类型。切平面稳定性准则用于确定候选平衡解的稳定性。吉布斯能最小化和切平面稳定性问题是具有挑战性的，由于高度非线性的热力学函数。本文提出了一种求解切平面稳定性问题的全局优化方法，为候选平衡解的稳定性提供了理论保证，同时提高了计算效率。立方状态方程的使用，因为它们能够准确地预测在很宽的压力范围内的非理想汽相和液相的行为。分析了稳定性问题的数学形式，并对具有特殊结构的非线性函数进行了辨识，以加快算法的收敛速度。这种方法应用于SRK、Peng-Robinson和货车van der Waals立方型状态方程时，可以处理各种混合规则。给出了两个八分量问题的计算结果。
Calculation of phase and chemical equilibria is of fundamental importance for the design and simulation of chemical processes. Methods of minimizing the Gibbs free energy provide equilibrium solutions that are candidates only for the true equilibrium solution, because the number and type of phases must be assumed before the Gibbs energy minimization problem can be formulated. The tangent plane stability criterion was used to determine the stability of a candidate equilibrium solution. The Gibbs energy minimization and tangent plane stability problems are challenging due to highly nonlinear thermodynamic functions. This work develops a global optimization approach for the tangent plane stability problem that provides a theoretical guarantee about the stability of the candidate equilibrium solution with computational efficiency. Cubic equations of state were used due to their ability to accurately predict the behavior of nonideal vapor and liquid phases across a broad range of pressures. The mathematical form of the stability problem was analyzed and nonlinear functions with special structure were identified to achieve faster convergence of the algorithm. This approach, when applied to the SRK, Peng-Robinson, and van der Waals cubic equations of state, could address a variety of mixing rules. Computational results on problems with two-eight components are presented.