Finite‐element steady state simulation of multiphase distillation

Abstract A finite‐element method is given for efficient simulation of multiphase distillation systems. Breakpoints are adaptively located to coincide with phase discontinuities. Thermodynamic criteria for the states at these discontinuities are included in the equation system. The adjustable breakpoint locations are calculated simultaneously with the other system variables by global Newton iteration. Worked examples demonstrate the accuracy and efficiency of the method.