Optimal Control of Step Growth Polymerizations

In the earlier chapters, the simulation of step growth polymerization in ideal (batch, plug flow or homogeneous, continuous flow stirred tank) reactors has been discussed. In order to simulate real reactors, the effects of several factors like residence time distribution in a continuous flow stirred tank reactor (for the case of perfect macromixing, Section 2.8), recycle in a plug flow reactor (Section 2.7), mass transfer limitations (Chapter 5), etc., were also investigated. It was shown that these variables have considerable effect on the performance of the reactor. In this chapter, attention is focused on the optimal control and operation of ideal reactors (PFRs and HCSTRs). For a given residence time of a batch reactor or an HCSTR, the variables that can be independently changed (degrees of freedom) are (a) the time history of the reactor temperature and (b) feed composition. Optimal conditions for these independent (or control) variables are determined in this chapter for simple ARB systems in order to establish the principles used. Optimization of industrially important systems like nylon 6 or PET polymerization is discussed in later chapters.