Use of the Stoichiometric Relationships in Complex Reaction Systems—Reaction Invariants

The possibility of extending the stoichiometry-based relationships between the changes of the species concentration in systems with higher complexity than those discussed in Chap. 2 is explored here. The concept of reaction invariants is employed to this end. Distributed flow systems in more than one spatial coordinate, as in homogeneous and catalytic packed-bed reactors, are analysed by considering effects such as dispersion, unsteady state, and the presence of permeable walls (e.g., membrane walls). Specific situations of practical interest are identified that do allow the existence of reaction invariants. Possible advantages of using stoichiometric relationships for the solution procedure of the mass conservation equations are also discussed.