BATCH REACTIVE DISTILLATION BREAD

Reactive Distillation processes combine the benefits of traditional unit operations with a substantial progress in reducing capital and operating costs and environmental impact (BP Review, 1997 Taylor and Krishna, 2000). 

However, conventional batch distillation with chemical reaction (reaction and separation taking place in the same vessel and hence referred to as Batch REActive Distillation- BREAD) is particularly suitable when one of the reaction products has a lower boiling point than other products and reactants. The higher volatility of this product results in a decrease in its concentration in the liquid phase, therefore increasing the liquid temperature and hence reaction rate, in the case of irreversible reaction. With reversible reactions, elimination of products by distillation favours the forward reaction. In both cases higher conversion of the reactants is expected than by reaction alone. Therefore, in both cases, higher amount of distillate (proportional to the increase in conversion of the reactant) with desired purity is expected than by distillation alone (as in traditional approach) (Mujtaba and Macchietto, 1997). 

An extensive literature survey shows that very little attention has been given to modelling and simulation of batch reactive distillation, let alone optimisation of such process. The published literature deals with the mathematical modelling and numerical integration of the resulting dynamic equations systems, with few presenting computer simulation vs experimental results. Only few authors have discussed the design, control and optimal operational aspects of batch reactive distillation processes. 

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In this section optimal operation problem of BREAD processes is presented as a proper dynamic optimisation problem incorporating a detailed dynamic model (Type V- CMH). The problem formulation and solution exploit the methods developed for non-reactive batch distillation by Mujtaba and Macchietto (1991, 1993,1998). These methods are also discussed in Chapters 5 and 6. 

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