Networks with large solvent recycle: Dynamics, hierarchical control, and a biorefinery application



A class of networks featuring large recycle of solvent is analyzed. This feature is central to numerous integrated processes which use solvents in various reaction and separation steps. A prototype network capturing the essential features of such networks is identified. Rigorous dynamic analysis reveals the presence of two time-scale dynamics exhibited by this prototype network. A systematic framework for model reduction and a subsequent hierarchical control design is proposed. The advantages of the proposed design over direct model-based control are demonstrated via a simulation case study. Finally, the application of the proposed framework to a newly proposed process for the production of 5-hydroxymethylfurfural from fructose is also presented. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1764–1777, 2012