Application of a plant-wide control design to the HDA process

With the increasing interest in and the need for plant-wide design and control, it is desirable to develop rigorous models for realistic and large-scale processes with recycle streams, energy integration and non-ideal systems, and use them for evaluating plant-wide control schemes. In this study, a rigorous model for the hydrodealkylation of toluene (HDA) process is developed using the commercial software, hysys.plant. After reviewing the reported methods for plant-wide control, a systematic method, namely, Control Configuration Design (CCD) method, is selected for application to the HDA process. The resulting control structures from the application of this method are evaluated and compared through rigorous dynamic simulation. The results show that the CCD method successfully yields workable base-level regulatory control structures for the HDA process. The control structures obtained by the CCD method are also compared with that reported by Luyben et al. (Plant-wide Process Control, McGraw-Hill, 1998) using their nine-step method.