Identification of Redundant Reaction Steps Based on Entropy Production

4 Identification of Redundant Reaction Steps Based on Entropy Production 

All of the previous methods identify redundant reactions via the inspection of the reaction rates or by the study of sensitivity matrices deduced from the kinetic system of differential equations. A very different approach is the application of thermodynamic functions for the identification of redundant reactions. This approach has common features with the derivation of numerical reduced models based on thermodynamics reasoning (see Sect. 7.10.4). 

Kooshkbaghi et al. (2014) published a systematic approach based on the relative contribution of each elementary reaction to the total entropy production. In a closed system, the total entropy production per unit volume is a positive semidefinite function that can be calculated in the following way  

The entropy production vanishes at equilibrium. The relative contribution of each reaction step to the total entropy production is given by 

Here R is the gas constant and Vfj and r/,j are the rates of the /-th forward and backward reaction steps, respectively. Kooshkbaghi et al. (2014) investigated the effect of eliminating all reaction steps having qj relative entropy production less than a threshold e for an example of an -heptane ignition mechanism. Their 

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