Introducing mechanistic kinetics to the Lagrangian Gibbs energy calculation

The Gibbs free energy minimum is usually calculated with the method of Lagrangian multipliers with the mass balance conditions as the necessary subsidiary conditions. Solution of the partial derivatives of the Lagrangian function provides the equilibrium condition of zero affinity for all stoichiome...

Full description

Saved in:
Bibliographic Details
Published in:Computers & chemical engineering 2006-05, Vol.30 (6), p.1189-1196
Main Authors: Koukkari, Pertti, Pajarre, Risto
Format: Article
Language:English
Subjects:
Gibbs energy minimization
Kinetic constraints
Lagrange multipliers
Process modeling
Reaction rate
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The Gibbs free energy minimum is usually calculated with the method of Lagrangian multipliers with the mass balance conditions as the necessary subsidiary conditions. Solution of the partial derivatives of the Lagrangian function provides the equilibrium condition of zero affinity for all stoichiometric equilibrium reactions in the multi-phase system. By extension of the stoichiometric matrix, reaction rate constraints can be included in the Gibbsian calculation. Zero affinity remains as the condition for equilibrium reactions, while kinetic reactions receive a non-zero affinity value, defined by an additional Lagrange multiplier. This can be algorithmically connected to a known reaction rate for each kinetically constrained species in the system. The presented method allows for several kinetically controlled reactions in the multi-phase Gibbs energy calculation.
ISSN:0098-1354
1873-4375
DOI:10.1016/j.compchemeng.2006.03.001