Reactors with Wrong-Way Behavior

The HDA reactor is unpacked and therefore cannot exhibit the wrongway behavior discussed in Chap. 4. However, it is quite common that gas phase reactions are carried out over a catalyst so it is important to understand the implications of the wrong-way behavior on the control of reactors with feed-effluent heat exchangers. 

To that end we have constructed a simulation of a fictitious system that has a severe inverse response. We show the design in Fig. 5.28 and give the design parameters in Table 5.1. The reactor has a large Lewis number (Le = 25), nearly complete per pass conversion of the reactant, and little axial dispersion. These are all factors necessary for wrong-way behavior. In fact the example plot of wrong-way behavior shown in Chap. 4 was generated from this reactor. 

We start by exploring the open-loop characteristics of the autothermal system with a 12 percent bypass rate. We already showed the steady- 

TABLE 5.1 Design Data for Reactor with Inverse Response 

20 kcal kmol-K 20 kcal/kmol K 100 kmol/h 15 atm 3S05C 

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