(117e) Heat Integrated Reactive Distillation of Mesityl Oxide Process

Significant advances have been made by industry and academic research organizations to establish the commercial advantages of Reactive Distillation (RD).  It is an effective but challenging technique for energy-efficient synthesis of major commodity chemicals with added advantages of process simplification.  However, the following key technical barriers hinder wider application of RD:  a) effective ways to improve contact between the catalyst and reacting phases; b) effective thermal management approaches to maintain an optimal global temperature profile that would also influence global distribution of reactants and the localized temperature distribution in the catalyst bed; and c) a fundamental rate-based model to elucidate the effect improvements in thermal management and catalyst contact might have on the localized reactive multi-phase flows.  This presentation will focus on the potential benefits of implementing several different thermal management approaches to a reactive distillation system.  The production of diacetone alcohol (DAA) and mesityl oxide (MO) from acetone dimerization and subsequent dehydration is used for illustration.  This reaction system is a good candidate for RD and experimental results have been previously reported in the literature.  Current literature analysis shows that the selectivity for DAA is quite sensitive to the reboiler heat duty, which indicates the thermal management in this RD process can play key role in optimizing the product selectivity, conversion rate, and energy efficiency.  In this analysis an Aspen+ model for a heat integrated reactive distillation (HIRD) was developed.  In one configuration, the latent heat from the overhead condenser was recovered and introduced at selected stages to determine the optimum heat integration.  Other configurations evaluated involved both the addition and removal of heat at different stages.  While the primary focus of the presentation will be on configurations with the greatest energy savings at constant throughput and purity, the effect of HIRD on production rate at a constant energy requirement will also be discussed.