Conceptual Design of Equilibrium Reactor−Reactive Distillation Flowsheets

Abstract

Economic and environmental reasons have led to process intensifications in the process industries. Reactive distillation is the most prominent example. However, often it is a challenge to satisfy the requirement for sufficient catalyst volume for the reaction while providing the interfacial area needed for mass transfer. The combination of a reactive distillation column with a pre-reactor is a valuable alternative. This paper presents an approach to identify promising designs for such flowsheets and the optimum distribution of the reaction extent between the pre-reactor and the reactive distillation column. The methodology uses a boundary value method for the design of the column; chemical equilibrium is assumed. The column usually consists of a reactive “core”, two rectifying sections, and one stripping section. The methodology will be demonstrated for the production of ethyl-tert-butyl-ether (ETBE).

A unifying framework for optimization-based design of integrated reaction–separation processes

“…The large internal recycle in column C2, which causes its high energy cost, can help to overcome the thermodynamic restriction of the low reaction rate to possibly result in lower catalyst cost. The reactive distillation column might also be more energy-efficient since heat generated by the exothermic reaction can compensate the reboiler heat input (Daniel and Jobson, 2007). Therefore, two additional variants are added to the variant tree: alternative 1.4, which extends variant 1.2 by including VRC for column C4 (C9) and alternative 1.5, which incorporates VRC for column C4 and replaces column C2 by a reactive distillation column (C10).…”

“…6. In contrast to a previous study on the ETBE process (Daniel and Jobson, 2007), which utilizes the boundary value method and assumes chemical equilibrium, the reactive column C10 of Table 4 Optimization results using rigorous models: cost contributions for process alternatives displayed in Fig. 5.…”

Rate-based analysis of reactive distillation sequences with different degrees of integration

“…Different methods, e.g., rectification body method (Lee et al, 2003) and boundary value method (Daniel and Jobson, 2007), have been presented in the literature for RD design. However, their implementation is not trivial.…”

Konzeptioneller Entwurf von Reaktions‐Destillations‐Prozessen mit Näherungsverfahren

“…Es handelt sich dabei zum einen um die konventionellen Oxeno-und Hüls-Prozesse [6,31] und zum anderen um die Reaktivdestillation [29,32], die hier aber nicht betrachtet wird. Die konventionellen Prozesse zur ETBE-Erzeugung ohne Ethanolrückgewinnung werden in diesem Abschnitt kurz skizziert, eine weitergehende Prozessbeschreibung findet sich in den erwähnten Quellen.…”