DETRIMENTAL INFLUENCE OF EXCESSIVE FRACTIONATION ON REACTIVE DISTILLATION

Reactive distillation has been demonstrated to reduce the capital cost and increase reactant conversion in MTBE production. These advantages are potentially transferable to the production of ETBE, TAME, and oth er tertiary ethers. However, the design of reactive distillation colum ns is complicated by interaction between phase and reaction equilibriu m. Whereas in conventional distillation, an increase in fractionation is always associated with an improvement in process performance (separ ation of key components), the same does not necessarily apply to react ive distillation. Using the production of ETBE as an example, several reactive distillation columns were designed for various feed compositi ons and design philosophies. It was found that the best designs incorp orated high reflux ratios with a restricted number of theoretical stag es, and that increasing the number of theoretical stages could actuall y be detrimental to process performance.