Investigation of Isobutene Dimerization Process In Reactive Distillation Using Rigorous Three-Phase Non-Equilibrium Stage Model

Amit Katariya1, Mariyana Chalakova2, Hannsjörg Freund1, Sanjay M. Mahajani3, and Kai Sundmacher4. (1) Physical and Chemical Process Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstr. 1, Magdeburg, 39106, Germany, (2) Process System Engineering, Otto-von-Guericke-University, Universitatplatz 2, Magdeburg, 39106, Germany, (3) Department of Chemical Engineering, Indian Institute of Technology, Bombay, I.I.T. Bombay, Powai, Mumbai 400076, India, (4) Process Systems Engineering, Otto-von-Guericke-Univ. Magdeburg, Universitaetsplatz 2, Magdeburg, 39016, Germany

Dimerization of isobutene is an important step in the production of isooctane, which is a potential gasoline fuel additive used for enhancing the octane number. The process for the production of isooctane involves dimerization of isobutene followed by subsequent hydrogenation of the formed dimer to isooctane. In the conventional scheme there are serious selectivity issues involved due to the presence of subsequent oligomerization reactions. Recently, dimerization has been successfully carried out in a reactive distillation column, and it was possible to significantly improve the yield of the desired dimer.

The present study involves the investigation of the process performance in the presence of mass and heat transfer limitations. It has also been found that mass transfer inside the catalyst pores is significant and has to be considered while modeling the process. Hence a rigorous three phase non-equilibrium (NEQ) stage model has been developed. The modeling of the mass transfer inside the catalyst pores in the presence of multiple non-linear reactions, and incorporating such model in a rigorous NEQ model is computationally intensive and challenging.