Combining reaction kinetics to the multi-phase Gibbs energy calculation

Development of robust and efficient methods for the computation of multi-phase systems has long been a challenge in both chemical and petroleum engineering as well as in materials science. Several techniques have been developed, particularly those which apply the Gibbs free energy minimization. In addition to calculation of global equilibrium problems, practical process simulation would benefit from algorithms, where reaction rates could be taken into account. In the present work, the method of Lagrange multipliers has been used to incorporate such additional constraints to the minimization problem, which allow a mechanistic reaction rate model to be included in the Gibbsian multi-component calculation. The method can be used to calculate the thermodynamic properties of a multi-phase system during a chemical change. The applications include computational materials science, industrial process modeling with known reaction rates combined with complex heat and mass transfer effects and studies of other non-equilibrium systems.