Feasibility of equilibrium-controlled reactive distillation process: application of residue curve mapping

Abstract The residue curve mapping technique (RCM) has been considered a powerful tool for the flow-sheet development and preliminary design of conventional multi-component separation processes. It does not only represent a good approximation to actual equilibrium behavior, but also it allows performing feasibility analysis of separation processes where non-ideal and azeotropic mixtures are involved. Applications of RCM to reactive distillation processes have recently been reported, but a generalized and systematic approach is still missing for the case of reactive feeds outside the conventional composition ranges and represents the aim of this contribution. An RCM-based feasibility analysis has been applied to the homogeneous reactive distillation synthesis of methyl tert-butyl ether (MTBE) at 11 atm from isobutene (IB) and methanol (MeOH) and in the presence of n-Butane (nC4). The reaction space, defined in terms of transformed composition variables, has been divided into sub-regions characterized by separation boundaries. A feasibility analysis of the reactive distillation process has been performed based upon the location of the reacting mixture, defined by [xMeOHF, xIBF, xnC4]∈[0, 1], and initial separation sequences have been generated according to the feed transformed-composition. In all the cases, high purity MTBE has been obtained.