Integrating economic targets for simulaltaneous structural and operational decision making in the design of the control recipe

Abstract

The interest in improving plant management is promoted by the benefits of dealing with more complex and versatile systems, which can adapt their production strategy to market fluctuations. In the present work, the capacity to adapt batch processes operation by solving flexible control recipes including structural and operational decisions is tackled. The problem is extrapolated from design and synthesis of processing networks, to find improved recipe solutions in multipurpose batch plants with given equipment sets for different economic scenarios. Process cell superstructure and process dynamics are modelled using algebraic – differential equations and general disjunctive programming (GDP). The obtained problem is a mixed-logic dynamic optimization (MLDO) problem, subsequently translated to a mixed-integer non-linear programming (MINLP) one. Denbigh Reaction case study is used as an example, by defining and comparing a fixed control recipe which is designed attending to processing objective function (i.e. product selectivity) and flexible recipes for different unitary costs scenarios and economic objective functions (i.e. profit and profitability). Improved operation is obtained from the economic point of view. This problem can be also considered for adaptation of operation strategies to new process requirements in a given plant where new equipment installation is not considered.