The need for the development of clean but still profitable processes and the study of low environmental impact and economically convenient management policies for them are two challenges for the years to come. This paper tries to give a first answer to the second of these needs, limited to the area of discontinuous productions. It deals with the development of a robust methodology for the profitable and clean management of (fed-)batch units under uncertainty, which can be referred to as a robust sustainability-oriented model-based optimization & control strategy. This procedure is specifically designed to ensure elevated process performances along with low-cost utilities usage reduction in realtime, simultaneously allowing for the effect of any external perturbation. In this way, conventional offline methods for process sustainable optimization can be easily overcome since the most suitable management policy, aimed at process sustainability, can be dynamically determined and applied in any operating condition. This leads to a significant step forward with respect to the nowadays options in terms of sustainable process management, that drives towards a cleaner and more energy-efficient future. The proposed theoretical framework is validated and tested on a case study based on the well-known fed-batch version of the Williams-Otto process to demonstrate its tangible benefits. The results achieved in this case study are promising and show that the framework is very effective in case of typical process operation while it is partially effective in case of unusual/unlikely critical process disturbances. Future works will go towards the removal of this weakness and further improvement in the algorithm robustness.
KeywordsDynamic optimization, non-linear model-predictive control, scenario-based programming, (fed-)batch processes sustainable management, low-cost utilities usage reduction.
IntroductionRecently, the social claim for the reduction in the pollution/environmental impact, originating from industrial activities, has paved the way to new research studies in the area of sustainable process design, optimization and real-time operation along with sustainable corporate-scale management. The primary aims of these new research areas consist of: the development of new process configurations and the revamping of the existing ones towards improved sustainability; the online or offline search for sustainable operating conditions, limited to the single plant or extended to the whole corporate scale. Many authors have been testing problems belonging to these research fields. Their efforts have produced a huge number of contributions concerning sustainable process design, offline optimization and corporate-scale management. For instance, studies concerning the optimization of supply-chain networks subject to additional sustainability constraints can be found in several papers. In detail, Giarola et al. (2014) and Ng and Lam (2013) study the problem limited to the field of bio-refineries while Vance et al. (2013) fo...