Two-point control of a reactive distillation column for composition and conversion

Reactive distillation is a hybrid process with dual process objectives: rea ctant conversion and product composition. Control schemes for reactive dist illation frequently neglect the effect of the principal operating parameter s on the reactant conversion, and this has a detrimental effect on the over all process profitability. An ETBE reactive distillation column has been us ed as a case study to show how a two-point control configuration, which rec ognises the importance of both composition and conversion, can be developed and implemented for a reactive distillation process. The combined composit ion and conversion control configuration was tested using SpeedUp dynamic s imulations and proved to be effective in maintaining a high isobutylene con version despite process disturbances. The two-point control scheme also had superior disturbance rejection capability, especially for feed rate change s, and composition set-point sensitivity compared with a one-point control scheme. (C) 1998 Elsevier Science Ltd. All rights reserved.