Unique influences of reboiler inventory control on the operation of totally reboiled reactive distillation columns

In this work, the dynamics and operation of the totally reboiled reactive distillation columns are visualized in terms of transfer function based process models. This kind of processes is found to be characterized by under-damped step responses due to the special topological configuration and the intricate interplay between the reaction operation and the separation operation involved. The under-dampness can be substantially alleviated through the tight inventory control of bottom reboiler and this presents beneficial effects to process dynamics and operation. Two totally reboiled reactive distillation columns, separating, respectively, a hypothetical synthesis reaction from reactants A and B to product C, and a real decomposition reaction from 1, 4-butanediol to tetrahydrofuran and water, are employed to demonstrate these uncommon behaviors. The results obtained give full support to the above qualitative interpretation. Despite the strong influences of reaction kinetics and thermodynamic properties of the reacting mixtures, the totally reboiled reactive distillation columns are generally considered to present such unique behaviors and require tight inventory control of bottom reboiler to facilitate their control system development.