R. Baur et al., Dynamic behaviour of reactive distillation tray columns described with a nonequilibrium cell model, CHEM ENG SC, 56(4), 2001, pp. 1721-1729
In this paper we develop a generic, dynamic, nonequilibrium (NEQ) cell mode
l for reactive distillation (RD) tray columns. The features of our model ar
e (1) the use of Maxwell-Stefan equations for describing mass transfer betw
een fluid phases, (2) the reaction is assumed to take place in the liquid p
hase, both within the diffusion layer and in the bulk, (3) the coupling bet
ween mass transfer and chemical reactions within the diffusion layer is acc
ounted for, and (4) the use of multiple well-mixed cells in the liquid and
vapour flow directions in order to account for staging in either fluid phas
e. The utility of the developed model is demonstrated by carrying out simul
ations of a RD column for production of ethylene glycol (EG) by hydration o
f ethylene oxide. The introduction of staging in the vapour and liquid phas
es improves the conversion to EG and also reduces the formation of the unwa
nted di-ethylene glycol. Furthermore, there are marked differences between
the dynamic column response to feed perturbations between the developed NEQ
model and the more commonly used equilibrium (EQ) stage model. (C) 2001 El
sevier Science Ltd. All rights reserved.