Extent of reaction and bifurcation diagrams

Diagrams such as Fig. 6.3, which show the dependence of the stationary-state composition on a particular parameter, are known as bifurcation diagrams. It is customary, when trying to judge the efficiency of various processes for instance, to discuss the extent of reaction rather than the concentration of the reactant. The former is the fractional conversion of A into products and is given by the difference between the inflow concentration of A and its stationary-state value, i.e. how much A has reacted, divided by the original (inflow) concentration. For the extent of reaction we use the symbol y, and under stationary-state conditions 

This is a dimensionless group y = 0 corresponds to no conversion y = 1 to complete conversion. 

at short residence times, where there is little conversion, the extent of conversion increases almost linearly with tres at long residence times the system tends to complete reaction yss - 1. 

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