Species Elimination via Trial and Error

The redundancy of individual species was also investigated by Turanyi (1990b) via a trial-and-error approach. A series of reduced mechanisms were created where in each one, all the consuming reactions of the tested species were removed. If the resulting simulation error (i.e. the deviation between the solutions of the full and reduced models) was small, then this species could be eliminated from the mechanism. The disadvantage of this method is that it is not able to identify species that can be eliminated in groups. An extension of this approach to the elimination of groups of species will be discussed in Sect. 7.6.1. 

23 Connectivity Method Connections Between the Species Defined by the Jacobian 

The connectivity method (CM) (Turanyi 1990c) identifies redundant species via the investigation of the Jacobian. Element (yjfj) dfjdy of the normalised Jacobian shows the percentage change of the production rate of species j due to a 1 % change in the concentration of species i. If the square of this effect is summed over all important species, then the value B,- shows the effect of a change in the concentration of each species on the concentrations of aU important species  

Species characterised by large B, values are closely connected to the important species and therefore are necessary species. In the next step, these necessary species are also included in the summation, and the B, values are recalculated. Species characterised by the largest B, values are again included in the summation, and this iteration is continued until all species that have close connection to the important species, directly or through other species, are identified. The rest of the species are considered to be redundant. 

Such an approach is taken in the Simulation Error Minimization Connectivity Method (SEM-CM) (Nagy and Turmyi 2009 Zsely et al. 2011). Using this method, several trial reduced mechanisms are created, and the simulation results obtained 

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