Internal Heat Integration and Controllability of Double Feed Reactive Distillation Columns, 2. Effect of Catalyst Redistribution

• Published in: Industrial & engineering chemistry research 2008-10, Vol.47 (19), p.7304-7311
• Main Authors: Pavan Kumar, M. V, Kaistha, Nitin
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Distillation; Exact sciences and technology; General and physical chemistry; Process Design and Control; Reactors; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie071639f

The effect of internal heat integration by catalyst redistribution on the controllability of an ideal and a methyl acetate reactive distillation (RD) column is studied. Conventional designs with feeds immediately above and below the reactive section are internally heat integrated by (a) extending the reactive section into the stripping section with catalyst redistribution, followed by (b) altering the feed tray locations. For the ideal RD system, only reactive section extension results in a design with a reboiler energy savings of 7.7%. The design obtained by reactive section extension followed by altered feed tray locations gives greater energy savings of 18.2%. For the methyl acetate system, simple reactive section extension with no change in the feed tray locations gives the most energy-efficient design with an energy savings of 39.7%. A comparison of the closed-loop performance of the two-point temperature control structures for the different designs demonstrates that temperature inferential control can be used to regulate the internally heat-integrated designs of both the ideal and methyl acetate systems. The controllability of the ideal RD column with full internal heat integration (both items (a) and (b) above) is found to be inferior to the conventional design. For the methyl acetate system, the controllability of the internally heat-integrated design is improved, relative to the conventional design.