Novel control strategy for intensified glycerol carbonate (GC) manufacturing process

Background: The overly produced by-product, glycerol (GLY), from the bio-diesel industry has resulted in serious environmental issues. Hence, processes that convert GLY to glycerol carbonate (GC) have recently been pro-posed. Subsequent to our previous study, the current paper uncovers the controllability of the reactive -distillation (RD) based GC manufacturing process.Method: Three control strategies without using composition loops were established. Their performance was evaluated based on the rejection of different types of disturbances (i.e. +/- 10% flowrate change,-10% change in the two feed streams, and 10%/20% catalyst deactivation). Notably, catalyst deactivation holds industrial sig-nificance, but has been barely studied in most control studies for the RD-based processes.Significant findings: Disturbances in feed flowrate and compositions are satisfactorily rejected by all the control structures. However, only the enhanced one (i.e. CS3) handles catalyst deactivation well. The reasons to suc-cessful controls are: (1) implementing a cascade temperature-control structure to the reactive distillation column stabilizes the changes in reaction conversion under dynamic operations; (2) employing temperature-difference control to a downstream column improves the indication of conversion by its bottom temperature. Further-more, the proposed concept of control is also applicable to other RD-based processes, which also use the highest -boiling species as a limited reactant.