The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Modelling a Process for Dimerisation of 2-Methylpropene

Tuomas Ouni

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Chemical Technology for public examination and debate in Auditorium KE2 at Helsinki University of Technology (Espoo, Finland) on the 19th of November, 2005, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-7926-6)   [2275 KB]
Dissertation is also available in print (ISBN 951-22-7925-8)

Abstract

Isooctane can be used to replace methyl-tert-butyl ether (MTBE) as a fuel additive. Isooctane is hydrogenated from isooctene, which is produced by dimerizing 2-methylpropene. In dimerization, two 2-methylpropene molecules react on ion-exchange resin catalyst to produce isooctene isomers (2,4,4-trimethyl-1-pentene, 2,4,4-trimethyl-2-pentene). Presence of 2-methyl-2-propanol (TBA) improves reaction selectivity. Trimers and tetramers are formed as side products. Water and alkenes have reaction equilibrium with corresponding alcohols.

The process configuration for isooctene production is a side reactor concept, and consists of reactor part, separation part (distillation tower) and a recycle structure (Figure 1). Units of miniplant at Helsinki University of Technology imitates the actual units of the isooctene production line in smaller scale, providing valuable information about the process and about the behaviour of individual units, as well as about the dynamics and operability of the process.

Ideology behind Miniplant is to separate thermodynamical models from hardware-specific models, so that they could be used as such in other contexts, e.g. in industrial scale. In the specific case of 2-methylpropene dimerisation the key thermodynamical models are vapour-liquid and liquid-liquid equilibrium as well as reaction kinetics. Hardware specific models include distillation column with spring-shaped packings and tubular catalytic reactor with heating coil and a thermowell. Developing these models through experiments and simulations was the primary target of this work.

This thesis consists of an overview and of the following 5 publications:

  1. Ouni T., Jakobsson K., Pyhälahti A. and Aittamaa J., Enhancing productivity of side reactor configuration through optimizing the reaction conditions. Chemical Engineering Research and Design 82 (2004) 167-174. © 2004 Institution of Chemical Engineers (IChemE). By permission.
  2. Ouni T., Uusi-Kyyny P., Pokki J.-P. and Aittamaa J., Isothermal vapor liquid equilibrium for binary 2-methylpropene + methanol to butanol systems. Journal of Chemical and Engineering Data 49 (2004) 787-794.
  3. Honkela M., Ouni T. and Krause O., Thermodynamics and kinetics of the dehydration of tert-butyl alcohol. Industrial & Engineering Chemistry Research 43 (2004) 4060-4065.
  4. Ouni T., Honkela M., Kolah A. and Aittamaa J., Isobutene dimerisation in a miniplant-scale reactor. Chemical Engineering and Processing, accepted for publication in October 2005. © 2005 Elsevier Science. By permission.
  5. Ouni T., Zaytseva A., Uusi-Kyyny P., Pokki J.-P. and Aittamaa J., Vapour–liquid equilibrium for the 2-methylpropane + methanol, +ethanol, +2-propanol, +2-butanol and +2-methyl-2-propanol systems at 313.15 K. Fluid Phase Equilibria 232 (2005) 90-99. © 2005 Elsevier Science. By permission.

Keywords: miniplant, distillation, reactor design, isobutene, side reactor concept

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© 2005 Helsinki University of Technology

Last update 2011-05-26