Control parameters, nonlinear chemical dynamics

Excitable systems as considered here are many particle systems far from eqnilibrium. Hence variables as voltage drop (neurons), light intensity (lasers) or densities (chemical reactions) are always subject to noise and fluctations. Their sources might be of quite different origin, first the thermal motion of the molecules, the discreteness of chemical events and the quantum uncertainness create some unavoidable internal fluctuations. Bnt in excitable systems, more importantly, the crucial role is played by external sources of fluctuations which act always in nonequilibrium and are not counterbalanced by dissipative forces. Hence their intensity and correlation times and lengths can be considered as independent variables and, subsequently, as new control parameters of the nonlinear dynamics. 

The nonlinear and nonstationary nature of a typical chemical process leads to a change in its dynamic characteristics during operation. To cope with this situation, a controller should be able to adjust its parameters in an optimum manner. Thus we are naturally led to the adaptive control systems which were discussed in Chapter 22. 

The purpose of this book is to present a comprehensive treatment of both steady-state design and dynamic control of reactive distillation systems using rigorous nonlinear models. Both generic ideal chemical systems and actual chemical systems are studied. Economic comparisons between conventional multiunit processes and reactive distillation are presented. Reactive distillation columns in isolation and in plantwide systems are considered. There are many parameters that affect the design of a reactive distUlation column. Some of these effects are counterintuitive because they are different than in conventional distillation. This is one of the reasons reactive distillation is such a fascinating subject. 

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