The problem of column simulation and optimization is studied in this paper. Equations for column simulation are derived based on strict thermodynamic properties calculations. Three kinds of optimization problem formulations are constructed and the reduced version of simultaneous method which takes advantage of the specialized structure of mathematical model for column simulation is preferred. Nonlinear constrained optimization is implemented with sequential quadratic programming codes. It is emphasized that the open structure of the simultaneous method is suitable for all simulation

and optimization problems. The differences lie only in the definitions of free variables and equality constraints. Example calculations show the performance and flexibili-ty of the proposed method.