New reduced parameters for flash calculations based on two-parameter BIP formula

摘要

Phase equilibrium calculations constitute a significant percentage of computational time in compositional simulation, especially as the number of components and phases increase. Reduced methods address this problem by carrying out phase equilibrium calculations using a reduced number of independent parameters. These methods have shown to speed up flash calculations, decrease simulation times, and also improve convergence behavior. In this paper, we present new reduced parameters using the two-parameter binary interaction parameter formula originally proposed by Li and Johns (2006). The new reduced parameters are applied to solve two-phase flash calculations for five different fluid descriptions. The results show a significant reduction in the number of iterations required to achieve convergence compared to the Li and Johns original approach. The improved method is also shown to converge more often than other flash calculation methods for the cases studied. We further compare computational times with the new reduced approach to conventional flash calculations based on the minimization of Gibbs energy using an optimized compiler.