Phase behavior in chemical reactors

Abstract

In this work, chemical reactor modelling is discussed from a phase behaviour point of view. In trickle-bed reactors (TBR), the origin of many critical phenomena lies especially in dynamic phase changes and in the distribution of phases.

For phase behaviour modelling purposes, two types of dynamic reactor models are presented: a trickle-bed reactor model and a gas phase particle model. In both models, special attention is focused on modelling the phase behaviour.

In catalytic multiphase reactors, the same reaction can take place both in gas phase and in liquid phase. Therefore the effects that a phase can have on the reaction rate are discussed. Also a relation between a gas phase and a liquid phase adsorption coefficient is derived. Furthermore, the same kinetic model is used for isooctene hydrogenation in gas and in liquid phase.

With respect to the modelling of phase equilibria, two types of non-ideal mixtures are presented. The applicability of SRK Boston-Mathias modification in calculating hydrogen solubility's in heavy hydrocarbons is tested. In addition, vapour-liquid equilibriua (VLE) are calculated for non ideal mixtures containing alcohol and hydrocarbon.

Also numerical solving methods of a multiphase reactor model are discussed. The method of moments is presented and applied to the calculation of dynamic plug flow reactor state profiles.