Simulation of kinetic effects in reactive distillation

This paper describes a simulation and modeling methodology for kinetically controlled, stage-wise reactive distillation columns, taking into account equimolar or non-equimolar reactions, side-reactions, effects of heat of reaction, non-constant latent heat effects, a distribution of liquid holdups on the reactive stages and hybrid sections in a column. A Damkohler number, which is the ratio of a characteristic liquid residence time to a characteristic reaction time, is introduced into the mathematical model. By changing the Damkohler number, the transition behavior from the nonreactive to the equilibrium reactive limits can be described. Combining the model type and the holdup distribution type on the reactive stages, four simulation strategies are studied: (1) non-heat effects model and constant molar holdup; (2) non-heat effects model and non-constant molar holdup; (3) heat effects model and constant molar holdup; (4) heat effects model and non-constant molar holdup. These strategies can be used to handle very diverse reactive distillation systems. The modeling tool capabilities are demonstrated with case studies for the metathesis of 2-pentene, MTBE synthesis and the hydration of ethylene oxide to ethylene glycol. For MTBE synthesis, the output multiplicities present at chemical reaction equilibrium disappear at lower extents of reaction (i.e. at lower residence times or Damkohler numbers). (C) 2000 Elsevier Science Ltd. All rights reserved.