(140b) Design Procedure For Integrated Reaction And Distillation

Reactive distillation offers potential reductions in the investment and operating costs, and less impact on environment. In some cases, it simplifies processes by integrating many single-operations into one physical shell. We have developed a feasibility evaluation method for reactive distillation systems with an arbitrary single reaction and then can predict whether a given combination of reaction and V-L-(L) separation can lead to the production of pure products in azeotropic mixtures. Major findings were1-3: 1) With an unstable node (UN) product that is reachable from all distillation regions by simple distillation, a reactive batch rectifier can produce pure products with reactions of the form aA+bB cC+dD or bB cC +dD. With one stable node (SN) product, its symmetric result is observed by using a batch reactive stripper. 2) With UN and SN products in reactions of the form aA+bB cC+dD or bB cC +dD, pure products can be produced in batch middle vessel columns and continuous single-feed columns when the products are in the same distillation region as a part of the reaction equilibrium curve. 3) If one of the products is a saddle (S) and no azeotrope exists between the products, then a single-feed column with a reaction of the form aA+bB cC+dD or bB cC +dD is still feasible, but only with large reaction equilibrium constants. 4) If both of the products are saddles and one of the products forms a minimum-boiling azeotrope with another product, then a batch rectifier with a side-feed entrainer or a continuous double-feed column can feasibly produce pure products with reactions of the form aA+bB cC+dD or bB cC +dD.

In this presentation, we will show how to explore the possibility of producing desired products from a combined mult-reaction and V-L-L separation by improving selectivity. We will introduce a simple method for estimating time-dependent still pot compositions in batch reactive distillation systems and its applicability for the feasibility evaluation.

1. Guo, Z., M. Ghufran, and J. W. Lee, ?Feasible products in Batch Reactive Distillation.? AIChE J., 49, 3161-3172 (2003). 2. Guo, Z. and J. W. Lee, ?Feasible products in Batch Reactive Extractive Distillation.? AIChE J., 50, 1484- 1492 (2004). 3. Guo, Z., J. Chin, and J. W. Lee, ?Feasibility of Continuous Reactive Distillation with Azeotropic Mixtures.? Ind. Eng. Chem. Res., 43, 3758-3769 (2004).