A MultiObjective Reactive Distillation Optimization Model for Fischerxe2x80x93Tropsch Synthesis Abstract   In the design of a reactive distillation column, aspects such as column configuration, catalyst loading, tray temperature, and side extraction rates should be well considered. Though preferences in Fischerxe2x80x93Tropsch (FT) synthesis may vary, it is acknowledged that the final product contains a wide range of hydrocarbons including fuel gas, gasoline, diesel, and linear wax. Zhang etxc2xa0al. (2018) previously developed an equationoriented framework for optimal synthesis of integrated reactive distillation systems for FT processes.  Here, we extend the mass, equilibrium, summation, and heat equations to a mathematical program with complementarity constraints to deal with possible dry trays in the nonreactive sections. The purpose of describing disappearing phases is to avoid infeasibilities due to multiple bilinear terms in the model for complicated model structures. The model is implemented by solving initialization steps and a sequence of nonlinear programming problems to determine an optimal structure and operating conditions.  Design specifications for multiple products could be set as individual objectives to determine design limits. Moreover, a balance of multiple objectives could be reached by formulating the reactive distillation model as a multiobjective optimization problem. In this work, we employ the augmented xcfxb5constraint method. The results show that significant design insights can be gained from the Paretooptimal front regarding acceptable tradeoffs among various objectives.

An Optimal Control Approach to Scheduling and Production in a Process using Decaying Catalysts Abstract   This article presents a novel approach to optimise scheduling and production planning to meet seasonal demand in an industrial process using decaying catalysts, based on its formulation as a multistage mixedinteger optimal control problem (MSMIOCP). Unlike existing methodologies, the MSMIOCP formulation allows to solve this problem as a standard nonlinear optimisation problem without combinatorial optimisation methods, which can be advantageous in providing reliable, robust and efficient solutions. Using this formulation, four case studies of this problem, differing in reaction or deactivation kinetics, are investigated. Two different solution implementations are used, each having their own relative advantages. The first implementation demonstrates a bangbang behaviour for the linear scheduling controls, consistent with a theoretical analysis, but faces integration problems and does not always produce high quality solutions. The second implementation, while not demonstrating the bangbang property, always produces high quality solutions and shows the advantages of the MSMIOCP formulation over existing methodologies.