Recycle of mass and energy is a feature present in almost all plants and industries. It is an inevitable characteristic found in actual industries due to the differences between the designed processes and the actual implementation. When a process is set in, engineers identify inefficiencies in the planned performance, and the use of recycle tries to reduce this difference. Although recycling helps to improve the plant¿s overall performance compared with the serial arrangement, its effect on plant dynamic behavior is seldom considered, and those changes start to affect features of the process like controllability and stability. Similarly, recycling affects the feasible region of individual equipment and its effect is not verified either.
Several works have demonstrated that advanced control strategies allow the improvement of the dynamic behavior of complex plants. Different techniques, like Model Based Predictive Control (MPC) and Plantwide Control (PWC), show that their implementation reduces the recycling effects. However, there is no explicit methodology to design those controllers to face the impacts of recycling over dynamic behavior and/or feasibility. Even, there is no tuning procedure to design the controllers that allow the optimization of the dynamic performance of plants, including the control system. In this sense, this works presents an analysis to characterize the effects of recycles over dynamic behavior of plants and how they affect the feasible operative region. Based on the previous analysis, a methodology of control will be proposed to design a PWC strategy, facing explicitly the dynamical phenomena of recycling on processes |